Publications by authors named "Michael Lell"

151 Publications

[Updated S2k AWMF guideline on obstructive sialadenitis].

Laryngorhinootologie 2021 10 6;100(10):793-798. Epub 2021 Oct 6.

HNO, Universitätsklinikum der FSU Jena, Germany.

The update of this guideline was an important step to define standards for the use of sialendoscopy and other emerging minimally invasive techniques for the therapy of sialolithiasis and other obstructive salivary gland diseases. The current actualization was necessary to adapt the diagnostic and therapeutic algorithms to the current scientific knowledge. In this article they are presented in a shortened version with a focus on conservative therapeutic measures which are especially relevant for daily practice.
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http://dx.doi.org/10.1055/a-1298-4241DOI Listing
October 2021

Effectiveness of Radiation Protection Caps for Lowering dose to the Brain and the Eye Lenses.

Cardiovasc Intervent Radiol 2021 Aug 13;44(8):1260-1265. Epub 2021 May 13.

Institute of Radiology, Universitätsklinikum Erlangen, Friedrich-Alexander-University Erlangen-Nuremberg, Maximiliansplatz 3, 91054, Erlangen, Germany.

Purpose: This work was designed to study the effectiveness of radiation protection caps in lowering the dose to the brain and the eye lens during fluoroscopically guided interventions.

Materials And Methods: Two types of radiation protection caps were examined with regards to their capacity to lower the radiation dose. One cap is equipped with lateral flaps, the other one is not. These caps were fitted to the head of an anthropomorphic Alderson-Rando (A.-R.) phantom. The phantom was positioned aside an angiographic table simulating the position of the first operator during a peripheral arterial intervention. One of the brain slices and both eyes of the A.-R. phantom were equipped with thermoluminescence dosimeters (TLDs).

Results: The analysis of the data showed that the cap without lateral flaps reduced the dose to the brain by 11,5-27,5 percent depending on the position within the brain. The cap with lateral protection flaps achieved a shielding effect between 44,7 and 78,9 percent. When evaluating the dose to the eye, we did see an increase of dose reduction from 63,3 to 66,5 percent in the left eye and from 45,8 to 46,8 percent in the right eye for the cap without lateral protection. When wearing the cap with lateral protection we observed an increase of dose reduction from 63,4 to 67,2 percent in the left eye and from 45,8 to 50,0 percent in the right eye.

Conclusion: Radiation protection caps can be an effective tool to reduce the dose to the brain and the eyes.
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http://dx.doi.org/10.1007/s00270-021-02831-3DOI Listing
August 2021

Deep learning-based coronary artery motion estimation and compensation for short-scan cardiac CT.

Med Phys 2021 Jul 26;48(7):3559-3571. Epub 2021 May 26.

German Cancer Research Center (DKFZ), Heidelberg, Germany.

Purpose: During a typical cardiac short scan, the heart can move several millimeters. As a result, the corresponding CT reconstructions may be corrupted by motion artifacts. Especially the assessment of small structures, such as the coronary arteries, is potentially impaired by the presence of these artifacts. In order to estimate and compensate for coronary artery motion, this manuscript proposes the deep partial angle-based motion compensation (Deep PAMoCo).

Methods: The basic principle of the Deep PAMoCo relies on the concept of partial angle reconstructions (PARs), that is, it divides the short scan data into several consecutive angular segments and reconstructs them separately. Subsequently, the PARs are deformed according to a motion vector field (MVF) such that they represent the same motion state and summed up to obtain the final motion-compensated reconstruction. However, in contrast to prior work that is based on the same principle, the Deep PAMoCo estimates and applies the MVF via a deep neural network to increase the computational performance as well as the quality of the motion compensated reconstructions.

Results: Using simulated data, it could be demonstrated that the Deep PAMoCo is able to remove almost all motion artifacts independent of the contrast, the radius and the motion amplitude of the coronary artery. In any case, the average error of the CT values along the coronary artery is about 25 HU while errors of up to 300 HU can be observed if no correction is applied. Similar results were obtained for clinical cardiac CT scans where the Deep PAMoCo clearly outperforms state-of-the-art coronary artery motion compensation approaches in terms of processing time as well as accuracy.

Conclusions: The Deep PAMoCo provides an efficient approach to increase the diagnostic value of cardiac CT scans even if they are highly corrupted by motion.
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http://dx.doi.org/10.1002/mp.14927DOI Listing
July 2021

High Intensity Resistance Exercise Training vs. High Intensity (Endurance) Interval Training to Fight Cardiometabolic Risk Factors in Overweight Men 30-50 Years Old.

Front Sports Act Living 2020 16;2:68. Epub 2020 Jun 16.

Institute of Medical Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.

Cardiovascular and cardiometabolic diseases are leading causes of death worldwide. Exercise favorably affects this problem, however only few invest (enough) time to favorably influence cardiometabolic risk-factors and cardiac morphology/performance. Time-effective, high-intensity, low-volume exercise protocols might increase people's commitment to exercise. To date, most research has focused on high-intensity interval training (HIIT), the endurance type of HIT, while corresponding HIT-resistance training protocols (HIT-RT) are rarely evaluated. In this study we compared the effect of HIIT vs. HIT-RT, predominately on cardiometabolic and cardiac parameters in untrained, overweight-obese, middle-aged men. Eligible, untrained men aged 30-50 years old in full-time employment were extracted from two joint exercise studies that randomly assigned participants to a HIIT, HIT-RT or corresponding control group. HIIT predominately consisted of interval training 90 s-12 min, (2-4 sessions/week), HIT-RT (2-3 sessions/week) was applied as a single set resistance training to muscular failure. Core intervention length of both protocols was 16 weeks. Main inclusion criteria were overweight-obese status (BMI 25-35 kg/m) and full employment (occupational working time: ≥38.5 h/week). Primary study-endpoint was the Metabolic Syndrome (MetS) Z-Score, secondary study-endpoints were ventricular stroke volume index (SVI) and myocardial mass index (MMI) as determined by Magnetic Resonance Imaging. The Intention to treat (ITT) principle was applied to analyze the summarized data set. Twenty-seven eligible men of the HIT-RT and 30 men of the HIIT group were included in the ITT. Both interventions significantly ( < 0.001) improve the MetS Z-Score, however the effect of HIIT was superior ( = 0.049). In parallel, HIT-RT and HIIT significantly affect SVI and MMI, with the effect of HIIT being much more pronounced ( < 0.001). Although HIIT endurance exercise was superior in favorably affecting cardiometabolic risk and particularly cardiac performance, both exercise methods positively affect cardiometabolic risk factors in this overweight to obese, middle-aged cohort of males with low time resources. Thus, the main practical application of our finding might be that in general overweight-obese people can freely choose their preferred exercise type (HIIT-END or HIT-RT) to improve their cardiometabolic health, while investing an amount of time that should be feasible for everybody. NCT01406730, NCT01766791.
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http://dx.doi.org/10.3389/fspor.2020.00068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7739822PMC
June 2020

Diagnostic value of 3D dynamic contrast-enhanced magnetic resonance imaging in lymph node metastases of head and neck tumors: a correlation study with histology.

Acta Radiol Open 2020 Aug 26;9(8):2058460120951966. Epub 2020 Aug 26.

Department of Radiology, University Hospital Erlangen, Erlangen, Germany.

Background: Accurate staging of cervical lymph nodes (LN) is pivotal for further clinical management of patients with head and neck cancer. Functional magnetic resonance imaging (MRI) such as three-dimensional (3D) dynamic contrast-enhanced (DCE) acquisition might improve the diagnosis of cervical LN metastases.

Purpose: To evaluate the additional diagnostic value of high-resolution 3D T1-weighted DCE in detecting LN metastasis compared to standard morphological imaging criteria in patients with head and neck tumors as correlated to histopathology.

Material And Methods: Standard MRI with 3D DCE acquisition at voxel sizes of 1 × 1×1 mm was performed in 15 patients before surgery; 92 LN of the head and neck were histopathologically analyzed. A logistic regression analysis of semi-quantitative DCE parameters, time-intensity curve (TIC) shapes, and morphological criteria was performed to differentiate benign from malignant LN.

Results: Standard MRI was sufficient for diagnosis of malignancy in LN with a short-axis diameter ≥ 15 mm (n = 17). For LN metastases with a short-axis diameter <15 mm (n = 12), however, the combination of 3D DCE MRI parameters, TIC shapes, and LN diameter significantly increased the sensitivity and specificity of diagnosing metastases (DCE + TIC shape + LN diameter: 92% and 88% vs. DCE only: 83% and 68% ( < 0.01) vs. LN diameter only: 83% and 77% ( = 0.04).

Conclusion: MRI including isotropic high-resolution 3D DCE acquisition combined with morphological criteria allows an accurate assessment of small cervical LN metastases in patients with head and neck cancer. For LN ≥ 15 mm diameter, morphologic imaging may suffice to diagnose metastatic disease to the LN.
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http://dx.doi.org/10.1177/2058460120951966DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7453466PMC
August 2020

[Artificial intelligence-based algorithms : Decision-making support for computed tomography of the chest].

Radiologe 2020 Oct;60(10):952-958

Institut für Radiologie und Nuklearmedizin, Klinikum Nürnberg, Paracelsus Medizinische Privatuniversität, Prof. Ernst-Nathan-Str. 1, 90419, Nürnberg, Deutschland.

Artificial intelligence (AI) algorithms are increasingly used in radiology. The main areas of application are, for example, the detection of lung lesions and the diagnosis of chronic obstructive and interstitial lung diseases. The aim of our study was to train and evaluate a package of algorithms that analyze data from computed tomographic (CT) images of the chest and provide quantitative measurements to the radiologist. The following algorithms were trained: lung lesion detection and measurement, lung lobe segmentation, vessel segmentation and measurement, coronary calcium scoring, measurement and density analysis of vertebral bodies. AI-supported algorithms will become part of daily routine of the radiologist in the future. Tasks that do not require medical expertise can be performed by AI. However, our results show that, based on the current accuracy, verification by an experienced radiologist is necessary.
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http://dx.doi.org/10.1007/s00117-020-00714-1DOI Listing
October 2020

Predictive Value of VIBE using Subtraction to Evaluate Idiopathic Facial Palsy after Starting Therapy.

Rofo 2020 Dec 9;192(12):1183-1189. Epub 2020 Jun 9.

Radiology, Erlangen University Hospital, Erlangen, Germany.

Purpose:  To determine the predictive value of 3-dimensional spoiled gradient-echo volumetric interpolated breath-hold examination (VIBE) using subtraction to evaluate the short-term effect of therapy for facial palsy.

Materials And Methods:  We included 97 patients with idiopathic facial palsy (52 male, 45 female; aged 50.7 ± 19.4 years) who underwent MR imaging with a contrast agent after starting therapy. The mean interval between onset and therapy was 1.55 ± 1.69 days, between therapy and MR imaging was 3.19 ± 2.78 days, and between MR imaging and assessment of the therapeutic effect was 3.50 ± 0.71 days. The degree of therapeutic effect was determined using a 4-grade scale based on the House-Brackmann scale for grading facial nerve function. Two radiologists reviewed VIBE with pre- and postcontrast subtraction using the 4-point scale. We evaluated the diagnostic performance and compared the degree of therapeutic effect and enhancement of facial nerves that were divided into 5 segments bilaterally.

Results:  We identified 98 facial palsy initially and significant enhancement in 55 facial nerves after the start of therapy and residual palsy in 87. Sensitivity for all facial palsy was 62.0 %, specificity was 90.9 %, positive predictive value was 98.2 %, negative predictive value was 23.3 %, and accuracy was 65.3 %. Eleven patients recovered completely, 1 showed significant enhancement, and the remaining 10 did not show significant enhancement of the facial nerve.

Conclusion:  VIBE has a potential to predict the prognostic outcome and assess facial palsy after the start of therapy.

Key Points:   · Three-dimensional spoiled gradient-echo volumetric interpolated breath-hold examination (VIBE) using subtraction can be useful to predict residual facial palsy after initial therapy.. · Strong enhancement of the facial nerve on VIBE using subtraction was associated with residual facial palsy after the start of therapy.. · Patients with a favorable prognosis did not show strong enhancement..

Citation Format: · Tomita H, Detmar K, Nakajima Y et al. Predictive Value of VIBE using Subtraction to Evaluate Idiopathic Facial Palsy after Starting Therapy. Fortschr Röntgenstr 2020; 192: 1183 - 1189.
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http://dx.doi.org/10.1055/a-1160-6047DOI Listing
December 2020

3D-Visualization of Neurovascular Compression at the Ventrolateral Medulla in Patients with Arterial Hypertension.

Clin Neuroradiol 2021 Jun 27;31(2):335-345. Epub 2020 May 27.

Department of Neurosurgery, Friedrich-Alexander University, Erlangen-Nuremberg (FAU), Erlangen, Germany.

Purpose: Controversy exists on the association of arterial hypertension (HTN) and neurovascular compression (NVC) at the ventrolateral medulla (VLM). No standardized and reproducible technique has been introduced yet for detection of NVC in HTN. This study aimed to generate, analyze and compare different results of exact reproducible anatomical 3D-representations of the VLM in patients with HTN, based on magnetic resonance imaging (MRI).

Methods: A 3T scanner provided MRI (T2-constructive interference in steady state (CISS) high resolution imaging and three-dimensional Time-of-flight (3D-TOF) angiography) from the posterior fossa of 44 patients with clinical treatment-resistant HTN. Image processing consists of segmentation of the CISS data, registration and fusion of the CISS and TOF data and visualization. For each patient two 3D-visualizations (before and after fusion) were obtained. The reproduction quality of the vessels, flow-related signal variability and pulsation artifacts were analyzed and compared, using a ranking score.

Results: Integrating vascular information from TOF into CISS data reduced artifacts in 3D-visualizations of exclusively processed CISS data. The quality of 3D-visualization of the vessels near the brain stem was significantly improved (p = 0.004). The results were reproducible and reliable. The quality of the 3D-presentations of neurovascular relationships at the VLM improved significantly (p < 0.001).

Conclusion: The 3D-visualization of fused image data provides an excellent overview of the relationship between cranial nerves and vessels at the VLM and simplifies the detection of NVC in HTN. It provides a powerful tool for future clinical and scientific research. Although microvascular decompression (MVD) in treatment resistant HTN is not a standard procedure, it can be discussed in selected patients with intractable severe HTN.
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http://dx.doi.org/10.1007/s00062-020-00916-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8211615PMC
June 2021

Automatic multi-organ segmentation in dual-energy CT (DECT) with dedicated 3D fully convolutional DECT networks.

Med Phys 2020 Feb 1;47(2):552-562. Epub 2020 Jan 1.

Pattern Recognition Lab, Universität Erlangen-Nürnberg, Erlangen, 91058, Germany.

Purpose: Dual-energy computed tomography (DECT) has shown great potential in many clinical applications. By incorporating the information from two different energy spectra, DECT provides higher contrast and reveals more material differences of tissues compared to conventional single-energy CT (SECT). Recent research shows that automatic multi-organ segmentation of DECT data can improve DECT clinical applications. However, most segmentation methods are designed for SECT, while DECT has been significantly less pronounced in research. Therefore, a novel approach is required that is able to take full advantage of the extra information provided by DECT.

Methods: In the scope of this work, we proposed four three-dimensional (3D) fully convolutional neural network algorithms for the automatic segmentation of DECT data. We incorporated the extra energy information differently and embedded the fusion of information in each of the network architectures.

Results: Quantitative evaluation using 45 thorax/abdomen DECT datasets acquired with a clinical dual-source CT system was investigated. The segmentation of six thoracic and abdominal organs (left and right lungs, liver, spleen, and left and right kidneys) were evaluated using a fivefold cross-validation strategy. In all of the tests, we achieved the best average Dice coefficients of 98% for the right lung, 98% for the left lung, 96% for the liver, 92% for the spleen, 95% for the right kidney, 93% for the left kidney, respectively. The network architectures exploit dual-energy spectra and outperform deep learning for SECT.

Conclusions: The results of the cross-validation show that our methods are feasible and promising. Successful tests on special clinical cases reveal that our methods have high adaptability in the practical application.
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http://dx.doi.org/10.1002/mp.13950DOI Listing
February 2020

Recent and Upcoming Technological Developments in Computed Tomography: High Speed, Low Dose, Deep Learning, Multienergy.

Invest Radiol 2020 01;55(1):8-19

Division of X-ray Imaging and CT (E025), German Cancer Research Center (DKFZ), Heidelberg, Germany.

The advent of computed tomography (CT) has revolutionized radiology, and this revolution is still going on. Starting as a pure head scanner, modern CT systems are now able to perform whole-body examinations within a couple of seconds in isotropic resolution, single-rotation whole-organ perfusion, and temporal resolution to fulfill the needs of cardiac CT. Because of the increasing number of CT examinations in all age groups and overall medical-driven radiation exposure, dose reduction remains a hot topic. Although fast gantry rotation, broad detector arrays, and different dual-energy solutions were main topics in the past years, new techniques such as photon counting detectors, powerful x-ray tubes for low-kV scanning, automated image preprocessing, and machine learning algorithms have moved into focus today.The aim of this article is to give an overview of the technical specifications of up-to-date available CT systems and recent hardware and software innovations for CT systems in the near future.
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http://dx.doi.org/10.1097/RLI.0000000000000601DOI Listing
January 2020

Effects of Conventional Uric Acid-Lowering Therapy on Monosodium Urate Crystal Deposits.

Arthritis Rheumatol 2020 01 10;72(1):150-156. Epub 2019 Dec 10.

Friedrich-Alexander University Erlangen-Nuremberg and Universitätsklinikum Erlangen, Erlangen, Germany.

Objective: Few studies have systematically and quantitatively addressed the impact of urate-lowering therapy on monosodium urate (MSU) deposits. This study was undertaken to analyze the effect of lifestyle measures and conventional urate-lowering therapy on MSU deposits in patients with gout.

Methods: In this prospective study, subjects with gout according to the American College of Rheumatology/European League Against Rheumatism classification criteria and presence of MSU deposits seen on dual-energy computed tomography (DECT) scans received either lifestyle intervention or conventional urate-lowering therapy for a mean period of 18 months before a follow-up DECT scan. Detected MSU deposits were quantified by volumetric measurement and validated by semiquantitative scoring, and baseline and follow-up measurements were compared.

Results: Baseline and follow-up DECT scans were available for all 83 subjects. Six subjects discontinued treatment, and 77 subjects underwent a lifestyle intervention (n = 24) or were treated with allopurinol (n = 29), febuxostat (n = 22), or benzbromarone (n = 2) over the entire observation period. The mean serum uric acid (UA) level decreased from 7.2 to 5.8 mg/dl in the overall population. In patients who discontinued treatment, no change in MSU deposits or serum UA levels was observed. The burden of MSU deposits significantly decreased in patients undergoing lifestyle intervention (MSU volume P = 0.007; MSU score P = 0.001), and in patients treated with allopurinol (MSU volume and score P < 0.001) or febuxostat (MSU volume P < 0.001; MSU score P = 0.001). No significant decline in MSU deposits was noted in patients who discontinued treatment.

Conclusion: These data show that lifestyle intervention and xanthine oxidase inhibitors significantly decrease the MSU deposit burden. Hence, conventional gout therapy not only lowers serum UA levels, but also reduces pathologic MSU deposits.
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http://dx.doi.org/10.1002/art.41063DOI Listing
January 2020

Transhepatic forceps biopsy after PTCD for histological assessment of bile duct stenoses or occlusions.

Z Gastroenterol 2019 Feb 12;57(2):133-138. Epub 2019 Feb 12.

Institute of Radiology and Nuclear Medicine, Klinikum Nürnberg Nord, Nürnberg, Germany.

Purpose:  The goal of this study was to evaluate the experience of 11 years of wire-guided forceps biopsy via PTCD in patients with obstructive jaundice.

Materials And Methods:  In a retrospective approach, 56 biopsies in 51 patients were analyzed (22 female, 29 male). Data was collected from 2006 to 2016. Mean age was 71 years (range: 34 - 86 years). Data was extracted from dig. Patients' records (KIS, PACS, RIS) to be analyzed in Microsoft Excel.

Results:  All 56 procedures were technically successful. Stenosis in anastomoses were benign due to scarring in 7 patients and in 9 due to papillitis or others. In 4 patients, results in anastomosis were malignant. In 19 patients without anastomosis, CCC was the diagnosis, thereof 10 klatskin, 9 stenosis in other locations, followed by gastric, pancreatic, and colon carcinoma in 5, 3, and 2 patients. Three patients had a CUP (multimetering in case of more than 1 related category). Overall results were 35 mal. and 16 benign, 76.8 % of all proc. had a correct histopathologic result, and 23.2 % were false negative. Sensitivity was 65.8 %, which results in negative predictive value of 58.1 %. There was no false positive and so specificity was 100 %, as was the positive predictive value. False negative results (no malignancy but clinically and imaging suspect) were corrected by rerunning the procedure, by CT-guided biopsy or by 1 PET-CT. In 1 case the surg. sample brought the result. Minor complications occurred in 8 patients: shivering in 1 case, distinct but hemodynamically not relevant hemobilia in 5 cases, 2 portovenal bleedings. All bleedings were short-term and self-limiting.

Conclusion:  Despite good feasibility, low peri- and post-interv. risk and high validity the forceps biopsy via PTCD is not widely used. For experienced interventionalists, it is an effective method for obtaining histology.
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http://dx.doi.org/10.1055/a-0821-7060DOI Listing
February 2019

Evaluation of ventricular septal defects using high pitch computed tomography angiography of the chest in children with complex congenital heart defects below one year of age.

J Cardiovasc Comput Tomogr 2019 Jul - Aug;13(4):226-233. Epub 2019 Feb 1.

University Hospital Erlangen, Department of Radiology, Maximiliansplatz 1, 91054, Erlangen, Germany; Imaging Science Institute Erlangen, Ulmenweg 18, 91054, Erlangen, Germany. Electronic address:

Background: Aim of this study was to assess the accuracy of ventricular septal defects (VSD) using high pitch computed tomography angiography (CTA) of the chest in children below 1 year of age, compared to the intraoperative findings and echocardiography.

Methods: Out of 154 patients that underwent Dual-Source CTA of the chest using a high-pitch protocol at low tube voltages (70-80 kV), 55 underwent surgical repair of a VSD (median age 8 days, range 1-348 days). The margins of the VSDs and their relation to the surrounding structures were reproduced by en-face views using multiplanar reformations (MPR). Absolute diameter, normalized area and relative area compared to the aortic valve annulus were used for discrimination between restrictive and non-restrictive defects. Localization was classified into four subtypes. The results were compared to two-dimensional echocardiography and intraoperative findings.

Results: Median absolute size of VSDs did not differ significantly between CTA-measurements (10.8 mm, range 2.8-18.1 mm) and intraoperative findings (12.0 mm, 3.0-25.0 mm, p = 0.09). Echocardiographic values were significantly lower (9.6 mm, 3.0-18.5 mm, both p < 0.01). The classification of the location and orientation matched the intraoperative situs in 96.4% of all cases using CT and in 87.3% using echocardiography. Echocardiography missed the relation to valves in 11% of all cases. Pre-interventional sensitivity and specificity for detection of a VSD were 97.2/98.9% compared to echocardiography. Median radiation dose was 0.32 mSv (range 0.12-2.00 mSv) and differed significantly between second and third generation Dual-Source CT (0.43 vs. 0.22 mSv, p = 0.003).

Conclusion: Size and subtype of VSDs can be accurately assessed by CTA of the chest in patients with complex congenital heart defects at a very low radiation dose.
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http://dx.doi.org/10.1016/j.jcct.2019.01.023DOI Listing
February 2020

Impact of voxel size and scan time on the accuracy of three-dimensional radiological imaging data from cone-beam computed tomography.

J Craniomaxillofac Surg 2018 Dec 19;46(12):2190-2196. Epub 2018 Sep 19.

Department of Prosthodontics (Head: Professor Dr. M. Wichmann), Erlangen University Hospital, Glückstraße 11, 91054, Erlangen, Germany. Electronic address:

Purpose: Three-dimensional (3D) radiological imaging plays an important role in surgical planning used in modern dentistry. The aim of this study was to optimize imaging parameters with a special focus on voxel size and scan time.

Material And Methods: A virtual 3D master model of a macerated human skull was generated using an industrial optical noncontact white light scanner. The skull was X-rayed with cone-beam computed tomography that was applied using different settings for voxel size and acquisition time (voxel edge length of 0.3 mm, scan times 4.8 s and 8.9 s; voxel edge length of 0.2 mm, scan times 14.7 s and 26.9 s). The scan was repeated 10 times at each setting. The CBCT scans were converted into 3D virtual models (actual value), which were superimposed with the 3D master model (reference value) to detect absolute differences.

Results: The mean value of deviation increased with increasing voxel size and decreasing scan time. For a voxel edge length of 0.3 mm, the mean values of deviation were 0.33 mm and 0.22 mm with scan times of 4.8 s and 8.9 s, respectively. For a voxel edge length of 0.2 mm, the mean deviations were 0.16 mm and 0.14 mm with scan times of 14.7 s and 26.9 s, respectively.

Conclusions: When using small voxel sizes, the scan time does not have a significant impact on image accuracy and therefore the scan time can be shortened. However, for larger voxel sizes, shorter scan times can lead to increased inaccuracy.
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http://dx.doi.org/10.1016/j.jcms.2018.09.002DOI Listing
December 2018

Towards context-sensitive CT imaging - organ-specific image formation for single (SECT) and dual energy computed tomography (DECT).

Med Phys 2018 Oct 31;45(10):4541-4557. Epub 2018 Aug 31.

German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.

Purpose: The purpose of this study was to establish a novel paradigm to facilitate radiologists' workflow - combining mutually exclusive CT image properties that emerge from different reconstructions, display settings and organ-dependent spectral evaluation methods into a single context-sensitive imaging by exploiting prior anatomical information.

Methods: The CT dataset is segmented and classified into different organs, for example, the liver, left and right kidney, spleen, aorta, and left and right lung as well as into the tissue types bone, fat, soft tissue, and vessels using a cascaded three-dimensional fully convolutional neural network (CNN) consisting of two successive 3D U-nets. The binary organ and tissue masks are transformed to tissue-related weighting coefficients that are used to allow individual organ-specific parameter settings in each anatomical region. Exploiting the prior knowledge, we develop a novel paradigm of a context-sensitive (CS) CT imaging consisting of a prior-based spatial resolution (CSR), display (CSD), and dual energy evaluation (CSDE). The CSR locally emphasizes desired image properties. On a per-voxel basis, the reconstruction most suitable for the organ, tissue type, and clinical indication is chosen automatically. Furthermore, an organ-specific windowing and display method is introduced that aims at providing superior image visualization. The CSDE analysis allows to simultaneously evaluate multiple organs and to show organ-specific DE overlays wherever appropriate. The ROIs that are required for a patient-specific calibration of the algorithms are automatically placed into the corresponding anatomical structures. The DE applications are selected and only applied to the specific organs based on the prior knowledge. The approach is evaluated using patient data acquired with a dual source CT system. The final CS images simultaneously link the indication-specific advantages of different parameter settings and result in images combining tissue-related desired image properties.

Results: A comparison with conventionally reconstructed images reveals an improved spatial resolution in highly attenuating objects and in air while the compound image maintains a low noise level in soft tissue. Furthermore, the tissue-related weighting coefficients allow for the combination of varying settings into one novel image display. We are, in principle, able to automate and standardize the spectral analysis of the DE data using prior anatomical information. Each tissue type is evaluated with its corresponding DE application simultaneously.

Conclusion: This work provides a proof of concept of CS imaging. Since radiologists are not aware of the presented method and the tool is not yet implemented in everyday clinical practice, a comprehensive clinical evaluation in a large cohort might be topic of future research. Nonetheless, the presented method has potential to facilitate workflow in clinical routine and could potentially improve diagnostic accuracy by improving sensitivity for incidental findings. It is a potential step toward the presentation of evermore increasingly complex information in CT and toward improving the radiologists workflow significantly since dealing with multiple CT reconstructions may no longer be necessary. The method can be readily generalized to multienergy data and also to other modalities.
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http://dx.doi.org/10.1002/mp.13127DOI Listing
October 2018

[The new German guideline on rhinosinusitis - an abbreviated version].

Laryngorhinootologie 2018 05 2;97(5):309-312. Epub 2018 May 2.

Praxis für Allgemeinmedizin, Kassel.

At the beginning of this year, the new German guideline on rhinosinusitis was published as a joint guideline of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery and the German College of General Practitioners and Family Physicians. The guideline was designed for the treatment of adult patients with inflammatory diseases of the paranasal sinuses and is addressed to all medical specialties involved in the management of these diseases. The current challenge is the implementation of this guideline in the clinical daily routine. For this purpose, an abbreviated version (miniature) was designed.
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http://dx.doi.org/10.1055/s-0044-100795DOI Listing
May 2018

Influence of scan time point and volume of intravenous contrast administration on blood-pool and liver SUVmax and SUVmean in [18F] FDG PET/CT.

Nuklearmedizin 2018 Apr 28;57(2):50-55. Epub 2018 Mar 28.

Aim: To investigate the influence of scan time point and volume of intravenous contrast material in 18F-FDG PET/CT on maximum and mean standardized uptake values (SUV/) in bloodpool and liver.

Methods: In 120 patients scheduled for routine whole-body 18F-FDG PET/CT the maximum and mean standardized uptake values (SUV/SUV) in the liver and blood pool were measured after varying scan time-point (delay 0 s-140 s post injectionem) and volume of contrast material (CM; 0 ml, 80 ml, 100 ml of 300 mg/ml of Iodine). Six groups of 20 patients were investigated: (1) without intravenous CM, (2-5) injection of 100 ml CM with a delay of 80 s (2), 100 s (3), 120 s (4), 140 s (5), and 80 ml CM and a delay of 100 s (6). SUV, SUV, maximum Hounsfield units (HU) and average Hounsfield units (HU) were calculated with the use of manually drawn regions of interests (ROIs) over the aortic arch and healthy liver tissue.

Results: SUV in bloodpool was significantly higher in group 3, 4 and 6 compared to group 1. Groups 2 and 5 also showed higher mean values of SUV, but the difference was not significant. SUV in bloodpool was also higher in groups 2, 3, 4, 5 and 6 compared to group 1, but the differences were only statistically significant in group 3. Both SUV and SUV in healthy liver tissue did not show significant differences when compared to the non contrast-enhanced control group.

Conclusion: SUV and to a lesser extent SUV measured in CM enhanced FDG PET/CT in blood pool could be significantly altered in high contrast CT examinations. This should be kept in mind in PET/CT protocols and evaluation relying on SUV and SUV, for example when used in the assessment of therapy response, especially in highly vascularized tumor lesions. ZIEL:: Das Ziel dieser Studie war den Einfluss von unterschiedlichen Messzeitpunkten und Volumina bei der Gabe von intravenösem Kontrastmittel in der 18F-FDG PET/CT auf SUV und SUV im Blutpool und Lebergewebe zu untersuchen.

Methoden: In 120 Patienten, geplant für eine Ganzkörper 18F-FDG -PET/CT, wurden die maximalen und durchschnittlichen standardisierten Aufnahmewerte (SUV/SUV) in der Leber und im Blutpool, jeweils nach unterschiedlichen Messzeitpunkten (Verzögerung 0 s-140 s post injectionem) und verschiedenen Volumina von Kontrastmittel (KM; 0 ml, 80 ml, 100 ml mit einer Konzentration von 300 mg/ml Jod) gemessen. Sechs Gruppen von je 20 Patienten wurden untersucht: (1) ohne intravenöses KM, (2-5) Injektion von 100 ml KM mit einer Verzögerung von 80 s (2), 100 s (3), 120 s (4), 140 s (5), und 80 ml KM mit einer Verzögerung von 100 s (6). Es wurden jeweils die SUV, SUV, die maximalen and die durchschnittlichen Hounsfield Einheiten (HU, HU) anhand manuell gezeichneter Bereiche von Interesse (ROIs) im Aortenbogen und im gesunden Lebergewebe berechnet.

Ergebnisse: Die SUV im Blutpool waren im Vergleich zur Gruppe 1 signifikant höher in Gruppe 3, 4 und 6. Die Gruppen 2 und 5 zeigten ebenfalls höhere Durchschnittswerte von SUV, der Unterschied war jedoch nicht signifikant. Die SUV im Blutpool waren im Vergleich zur Gruppe 1 ebenfalls höher in den Gruppen 2, 3, 4, 5 und 6, allerdings waren die Unterschiede nur in Gruppe 3 statistisch signifikant. Im Lebergewebe zeigten sowohl SUV, als auch SUV keine signifikanten Unterschiede im Vergleich zu der nativen Kontrollgruppe.

Schlussfolgerungen: In der Kontrastmittel-gestützten FDG PET/CT können die SUV und in geringerem Ausmaß auch SUV im Blutpool durch Hochkontrast-CT Untersuchungen signifikant beeinflusst werden. Dies sollte bei PET/CT Protokollen bzw. Auswertungen, die auf SUV und SUV beruhen, berücksichtigt werden, zum Beispiel bei der Beurteilung des Therapieansprechens insbesondere bei stark vaskularisiertem Tumorgewebe.
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http://dx.doi.org/10.3413/Nukmed-0919-17-08DOI Listing
April 2018

MRI to investigate iliac artery wall thickness in triathletes.

Phys Sportsmed 2018 09 20;46(3):393-398. Epub 2018 Mar 20.

a Department of Vascular Surgery , University Hospital , Erlangen , Germany.

Objectives: Endofibrosis was first described in endurance athletes. This rare disease is characterized by intimal hyperplasia of iliac arteries. Due to non-specific symptoms diagnosing could be very challenging and delayed. This represents a serious problem not only for affected athletes but also for consulting physicians. The aim of this study was to analyze intimal thickness of iliac arteries using non-contrast magnetic resonance imaging (MRI) in competitive triathletes suffering from exercise induced leg pain consistent with symptoms caused by endofibrosis.

Methods: 18 highly trained triathletes (16 triathletes, 12 male) with a mean age of 45.4 ± 10.2 years were investigated by non-contrast MRI. We divided subjects into two groups: 10 complaint about exercise- induced leg pain and 7 were free of any symptoms. In all 10 symptomatic athletes consulting physicians excluded musculoskeletal or neurological disorders before and we suspected endofibrosis. One patient was excluded from statistical analysis due to a known recurrent external iliac artery (EIA) occlusion after surgical repair 6 month ago.

Results: Mean wall thickness (T) of all 17 subjects was 1.34 ± 0.11mm for the common iliac artery (CIA) and 1.74 ± 0.18mm for the EIA. We found no significant differences by comparing T of symptomatic (s) and asymptomatic (a) legs. There were no significant differences in mean ratio of patent artery to whole artery between the symptomatic and asymptomatic legs for the CIA (0.81 vs 0.82, p = 0.87) and for the EIA (0.71 vs 0.72, p = 0.78). MRI shows a thickening of the left EIA (4.41mm) in the patient who suffered from recurrent occlusion of the left EIA and after surgical repair and histological examination confirmed an endofibrotic lesion.

Conclusion: Non-contrast MRI seems to be an appropriate diagnostic tool to exclude endofibrosis in triathletes, but it cannot be recommended as initial screening modality for athletes suffering from exercise-induced leg pain.
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http://dx.doi.org/10.1080/00913847.2018.1450060DOI Listing
September 2018

Advanced Modeled Iterative Reconstruction (ADMIRE) Facilitates Radiation Dose Reduction in Abdominal CT.

Acad Radiol 2018 10 1;25(10):1277-1284. Epub 2018 Mar 1.

Institute of Radiology, University Hospital Erlangen-Nuernberg, University of Erlangen-Nuernberg, Maximiliansplatz 1, 91054 Erlangen, Germany.

Rationale And Objectives: This study aimed to determine the potential degree of radiation dose reduction achievable using Advanced Modeled Iterative Reconstruction (ADMIRE) in abdominal computed tomography (CT) while maintaining image quality. Moreover, this study compared differences in image noise reduction of this iterative algorithm with radiation dose reduction.

Methods: Eleven consecutive patients scheduled for abdominal CT were scanned according to our institute's standard protocol (100 kV, 289 reference mAs). Using a proprietary reconstruction software, CT images of these patients were reconstructed as either full-dose weighted filtered back projections or with simulated radiation dose reductions down to 10% of the full-dose level and ADMIRE at either strength 3 or strength 5. Images were marked with arrows pointing on anatomic structures of the abdomen, differing in their contrast to the surrounding tissue. Structures were grouped into high-, medium-, and low-contrast subgroups. In addition, the intrinsic noise of these structures was measured. That followed, image pairs were presented to observers, with five readers assessing image quality using two-alternative-forced-choice comparisons. In total, 3000 comparisons were performed that way.

Results: Both ADMIRE 3 and 5 decreased noise of the anatomic structures significantly compared to the filtered back projection, with an additional significant difference between ADMIRE 3 and 5. Radiation dose reduction potential for ADMIRE ranged from 29.0% to 53.5%, with no significant differences between ADMIRE 3 and 5 within the contrast subgroups.The potential levels of radiation dose reduction for ADMIRE 3 differed significantly between high-, medium-, and low-contrast structures, whereas for ADMIRE 5, there was only a significant difference between the high- and the medium-contrast subgroups.

Conclusion: Although ADMIRE 5 permits significantly higher noise reduction potential than ADMIRE 3, it does not facilitate higher levels of radiation dose reduction. ADMIRE nonetheless holds remarkable potential for radiation dose reduction, which features a certain dependency on the contrast of the structure of interest. Applying ADMIRE with a strength of 3 in abdominal CT may permit radiation dose reduction of about 30%.
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http://dx.doi.org/10.1016/j.acra.2018.01.014DOI Listing
October 2018

Diagnostics and therapy of vestibular schwannomas - an interdisciplinary challenge.

GMS Curr Top Otorhinolaryngol Head Neck Surg 2017 18;16:Doc03. Epub 2017 Dec 18.

Department of Neurosurgery, Helios Hospital of Erfurt, Germany.

Vestibular schwannomas (VS) expand slowly in the internal auditory canal, in the cerebellopontine angle, inside the cochlear and the labyrinth. Larger tumors can displace and compress the brainstem. With an annual incidence of 1:100,000 vestibular schwannoma represent 6-7% of all intracranial tumors. In the cerebellopontine angle they are by far the most neoplasm with 90% of all lesions located in this region. Magnetic resonance imaging (MRI), audiometry, and vestibular diagnostics are the mainstays of the clinical workup for patients harboring tumors. The first part of this paper delivers an overview of tumor stages, the most common grading scales for facial nerve function and hearing as well as a short introduction to the examination of vestibular function. Upholding or improving quality of life is the central concern in counseling and treating a patient with vestibular schwannoma. Preservation of neuronal function is essential and the management options - watchful waiting, microsurgery and stereotactic radiation - should be custom-tailored to the individual situation of the patient. Continuing interdisciplinary exchange is important to monitor treatment quality and to improve treatment results. Recently, several articles and reviews have been published on the topic of vestibular schwannoma. On the occasion of the 88 annual meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck surgery a special volume of the journal "HNO" will be printed. Hence this presentation has been designed to deviate from the traditional standard which commonly consists of a pure literature review. The current paper was conceptually woven around a series of interdisciplinary cases that outline examples for every stage of the disease that show characteristic results for management options to date. Systematic clinical decision pathways have been deduced from our experience and from results reported in the literature. These pathways are graphically outlined after the case presentations. Important criteria for decision making are size and growth rate of the tumor, hearing of the patient and the probability of total tumor resection with preservation of hearing and facial nerve function, age and comorbidity of the patient, best possible control of vertigo and tinnitus and last but not least the patient's preference and choice. In addition to this, the experience and the results of a given center with each treatment modality will figure in the decision making process. We will discuss findings that are reported in the literature regarding facial nerve function, hearing, vertigo, tinnitus, and headache and reflect on recent studies on their influence on the patient's quality of life. Vertigo plays an essential role in this framework since it is an independent predictor of quality of life and a patient's dependence on social welfare. Pathognomonic bilateral vestibular schwannomas that occur in patients suffering from neurofibromatosis typ-2 (NF2) differ from spontaneous unilateral tumors in their biologic behavior. Treatment of neurofibromatosis type-2 patients requires a multidisciplinary team, especially because of the multitude of separate intracranial and spinal lesions. Off-label chemotherapy with Bevacizumab can stabilize tumor size of vestibular schwannomas and even improve hearing over longer periods of time. Hearing rehabilitation in NF2 patients can be achieved with cochlear and auditory brainstem implants.
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http://dx.doi.org/10.3205/cto000142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5738934PMC
December 2017

Impact of Contrast Media Concentration on Low-Kilovolt Computed Tomography Angiography: A Systematic Preclinical Approach.

Invest Radiol 2018 05;53(5):264-270

Objectives: Low peak kilovoltage (kVp) protocols in computed tomography angiography (CTA) demand a review of contrast media (CM) administration practices. The aim of this study was to systematically evaluate different iodine concentrations of CM in a porcine model.

Materials And Methods: Dynamic 70 kVp CTA was performed on 7 pigs using a third-generation dual-source CT system. Three CM injection protocols (A-C) with an identical total iodine dose and iodine delivery rate (150 mg I/kg, 12 s, 0.75 g I/s) differed in iodine concentration and flow rate (protocol A: 400 mg I/mL, 1.9 mL/s; B: 300 mg I/mL, 2.5 mL/s; C: 150 mg I/mL, 5 mL/s). All protocols were applied in a randomized order and compared intraindividually. Arterial enhancement at different locations in the pulmonary artery, the aorta, and aortic branches was measured over time. Time attenuation curves, peak enhancement, time to peak, and bolus tracking delay times needed for static CTA were calculated. The reproducibility of optimal parameters was tested in single-phase CTA.

Results: The heart rates of the pigs were comparable for all protocols (P > 0.7). The injection pressure was significantly higher for protocol A (64 ± 5 psi) and protocol C (55 ± 3 psi) compared with protocol B (39 ± 2 psi) (P < 0.001). Average arterial peak enhancement in the dynamic scans was 359 ± 51 HU (protocol A), 382 ± 36 HU (B), and 382 ± 60 HU (C) (A compared with B and C: P < 0.01; B compared with C: P = 0.995). Time to peak enhancement decreased with increasing injection rate. The delay time for bolus tracking depended on the injection rate as well and was highest for protocol A (4.7 seconds) and lowest for protocol C (3.9 seconds) (P = 0.038). The peak enhancement values of the dynamic scans highly correlated with those of the single-phase CTA scans.

Conclusions: In 70 kVp CTA, 300 mg I/mL iodine concentrations showed to be superior to high-concentration CM when keeping the iodine delivery rate constant. Besides, iodine concentrations as low as 150 mg I/mL can be administered without compromising vascular enhancement. This opens up new possibilities in CM administration.
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May 2018

Myocardial adaption to HI(R)T in previously untrained men with a randomized, longitudinal cardiac MR imaging study (Physical adaptions in Untrained on Strength and Heart trial, PUSH-trial).

PLoS One 2017 7;12(12):e0189204. Epub 2017 Dec 7.

Department of Radiology and Nuclear Medicine, Hospital of Nuremberg, Paracelsus Medical University, Nuremberg, Bavaria, Germany.

Objective: Although musculoskeletal effects in resistance training are well described, little is known about structural and functional cardiac adaption in formerly untrained subjects. We prospectively evaluated whether short term high intensity (resistance) training (HI(R)T) induces detectable morphologic cardiac changes in previously untrained men in a randomized controlled magnetic resonance imaging (MRI) study.

Materials And Methods: 80 untrained middle-aged men were randomly assigned to a HI(R)T-group (n = 40; 43.5±5.9 years) or an inactive control group (n = 40; 42.0±6.3 years). HI(R)T comprised 22 weeks of training focusing on a single-set to failure protocol in 2-3 sessions/week, each with 10-13 exercises addressing main muscle groups. Repetitions were decreased from 8-10 to 3-5 during study period. Before and after HI(R)T all subjects underwent physiologic examination and cardiac MRI (cine imaging, tagging).

Results: Indexed left (LV) and right ventricular (RV) volume (LV: 76.8±15.6 to 78.7±14.8 ml/m2; RV: 77.0±15.5 to 78.7±15.1 ml/m2) and mass (LV: 55.5±9.7 to 57.0±8.8 g/m2; RV: 14.6±3.0 to 15.0±2.9 g/m2) significantly increased with HI(R)T (all p<0.001). Mean LV and RV remodeling indices of HI(R)T-group did not alter with training (0.73g/mL and 0.19g/mL, respectively [p = 0.96 and p = 0.87]), indicating balanced cardiac adaption. Indexed LV (48.4±11.1 to 50.8±11.0 ml/m2) and RV (48.5±11.0 to 50.6±10.7 ml/m2) stroke volume significantly increased with HI(R)T (p<0.001). Myocardial strain and strain rates did not change following resistance exercise. Left atrial volume at end systole slightly increased after HI(R)T (36.2±7.9 to 37.0±8.4 ml/m2, p = 0.411), the ratio to end-diastolic LV volume at baseline and post-training was unchanged (0.47 vs. 0.47, p = 0.79).

Conclusion: 22 weeks of HI(R)T lead to measurable, physiological changes in cardiac atrial and ventricular morphologic characteristics and function in previously untrained men.

Trial Regristration: The PUSH-trial is registered at the US National Institutes of Health (ClinicalTrials.gov), NCT01766791.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0189204PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5720775PMC
December 2017

[Diagnosis and Management of Vestibular Schwannomas - An Interdisciplinary Challenge].

Laryngorhinootologie 2017 Apr 16;96(S 01):S152-S182. Epub 2017 Oct 16.

Hals-Nasen-Ohren-Klinik, Universitätsklinikum Erlangen.

Vestibular schwannomas expand slowly in the internal auditory canal, in the cerebellopontine angle, inside the cochlear and the labyrinth. Larger tumors can displace and compress the brainstem. With an annual incidence of 1:100 000 vestibular schwannoma represent 6-7% of all intracranial tumors. In the cerebellopontine angle they are by far the most neoplasm with 90% of all lesions located in this region. Magnetic resonance imaging (MRI), audiometry, and vestibular diagnostics are the mainstays of the clinical workup for patients harboring tumors. The first part of this paper delivers an overview of tumor stages, the most common grading scales for facial nerve function and hearing as well as a short introduction to the examination of vestibular function.Upholding or improving quality of life is the central concern in counseling and treating a patient with vestibular schwannoma. Preservation of neuronal function is essential and the management options - watchful waiting, microsurgery and stereotactic radiation - should be custom-tailored to the individual situation of the patient. Continuing interdisciplinary exchange is important to monitor treatment quality and to improve treatment results. Recently, several manuscripts and reviews have been published on the topic of vestibular schwanomma. On the occasion of the 88 annual meeting of the German Society of Oto-rhino-laryngology, Head and Neck surgery a special volume of the journal "HNO" will be printed. Hence this presentation has been designed to deviate from the traditional standard which commonly consists of a pure literature review. The current paper was conceptually woven around a series of interdisciplinary cases which outlines examples for every stage of the disease that show characteristic results for management options to date. Systematic clinical decision pathways have been deduced from our experience and from results reported in the literature. These pathways are graphically outlined after the case presentations. Important criteria for decision making are size and growth rate of the tumor, hearing of the patient and the probability of total tumor resection with preservation of hearing and facial nerve function, age and co-morbidity of the patient, best possible control of vertigo and tinnitus and last but not least the patient's preference and choice. In addition to this, the experience and the results of a given center with each treatment modality will figure in the decision making process.We will discuss findings that are reported in the literature regarding facial nerve function, hearing, vertigo, tinnitus, and headache and reflect on recent studies on their influence on the patient's quality of life. Vertigo plays an essential role in this framework since it is an independent predictor of quality of life and a patient's dependence on social welfare.Pathognomonic bilateral vestibular schwannoma that occur in patients suffering from neurofibromatosis typ-2 (NF2) differ from spontaneous unilateral tumors in their biologic behavior. Treatment of neurofibromatosis type-2 patients requires a multidisciplinary team, especially because of the multitude of separate intracranial and spinal lesions.Off-label chemotherapy with Bevacizumab can stabilize tumor size of vestibular schwannomas and even improve hearing over longer periods of time. Hearing rehabilitation in NF2 patients can be achieved with cochlea and auditory brainstem implants.
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http://dx.doi.org/10.1055/s-0042-122386DOI Listing
April 2017

Does formalin fixation influence MSCT/CBCT accuracy?

Surg Radiol Anat 2018 Jan 21;40(1):31-37. Epub 2017 Aug 21.

Department of Prosthodontics, Erlangen University Hospital, Glueckstraße 11, 91054, Erlangen, Germany.

Purpose: Advanced imaging modalities, such as multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT), greatly facilitate diagnostic medicine. In radiological research, it is important to know how accurately a scanned object is visualized, and whether the methodology leads to image distortion. The objective of this study was to evaluate whether formalin fixation impacted the accuracy of virtual 3D bone models generated via CBCT and MSCT using a software-based evaluation method that excluded human measurement errors.

Methods: A head specimen, with and without formalin preservation, was subjected to MSCT and CBCT scans using the manufacturers' predefined scanning protocols. Digital models of the lower jaw were constructed and superimposed with a master model generated based on optical scanning with an industrial non-contact scanner. Means and standard deviations were calculated to assess accuracy, and a t test was used for comparisons between the fixed and unfixed specimens.

Results: The extent of discrepancy between the fixed and unfixed specimens was analyzed using a total of 200 points (n = 200) in each specimen state. The mean deviation between states was 0.01 mm for MSCT (at both 80 and 140 kV). Mean values from CBCT at 0.4 voxel did not differ between states.

Conclusions: Our results suggest that formalin fixation of an anatomical specimen does not substantially affect the accuracy of a three-dimensional image generated with CBCT and MSCT. Thus, fixed specimen can be used in future investigations of 3D models without concerns regarding the accuracy.
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http://dx.doi.org/10.1007/s00276-017-1908-xDOI Listing
January 2018

Image quality, diagnostic accuracy, and potential for radiation dose reduction in thoracoabdominal CT, using Sinogram Affirmed Iterative Reconstruction (SAFIRE) technique in a longitudinal study.

PLoS One 2017 5;12(7):e0180302. Epub 2017 Jul 5.

Department of Radiology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.

Objective: To step-wise evaluate image quality of sinogram-affirmed iterative reconstruction (SAFIRE) in reduced-dose (RD) thoracoabdominal computed tomography (CT) compared to full-dose (FD) and RD filtered back projection (FBP) in a longitudinal study.

Materials And Methods: 122 patients were included in this prospective study. 49 patients (14 men: mean age ± SD, 56±0.4 years; 35 women: 58±1.3 years) completed FD, RD1 (80%-dose) and RD2 (60%-dose) thoracoabdominal CT. Each CT dataset was reconstructed with FBP and SAFIRE. For quantitative image analysis image noise was measured in defined tissue regions. Qualitative image evaluation was performed according to the European Guidelines on Quality criteria for CT. Additionally artifacts, lesion conspicuity, and edge sharpness were assessed.

Results: Compared to FD-FBP noise in soft tissue increased by 12% in RD1-FBP and 27% in RD2-FBP reconstructions, whereas SAFIRE lead to a decrease of 28% (RD1) and 17% (RD2), respectively (all p <0.001). Visually sharp reproduction, lesion conspicuity, edge sharpness of pathologic findings, and overall image quality did not differ statistically significant between FD-FBP and RD-SAFIRE datasets. Image quality decreased in RD1- and RD2-FBP compared to FD-FBP, reaching statistically significance in RD2 datasets (p <0.001). In RD1- and RD2-FBP (p <0.001) streak artifacts were noted.

Conclusion: Using SAFIRE the reference mAs in thoracoabdominal CT can be reduced by at least 30% in clinical routine without loss of image quality or diagnostic information.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180302PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5498038PMC
October 2017

Protein Supplementation to Augment the Effects of High Intensity Resistance Training in Untrained Middle-Aged Males: The Randomized Controlled PUSH Trial.

Biomed Res Int 2017 1;2017:3619398. Epub 2017 Jun 1.

Institute of Medical Physics, Friedrich-Alexander University of Erlangen-Nürnberg, Henkestraße 91, 91052 Erlangen, Germany.

High intensity (resistance exercise) training (HIT) defined as a "single set resistance exercise to muscular failure" is an efficient exercise method that allows people with low time budgets to realize an adequate training stimulus. Although there is an ongoing discussion, recent meta-analysis suggests the significant superiority of multiple set (MST) methods for body composition and strength parameters. The aim of this study is to determine whether additional protein supplementation may increase the effect of a HIT-protocol on body composition and strength to an equal MST-level. One hundred and twenty untrained males 30-50 years old were randomly allocated to three groups: (a) HIT, (b) HIT and protein supplementation (HIT&P), and (c) waiting-control (CG) and (after cross-over) high volume/high-intensity-training (HVHIT). HIT was defined as "single set to failure protocol" while HVHIT consistently applied two equal sets. Protein supplementation provided an overall intake of 1.5-1.7 g/kg/d/body mass. Primary study endpoint was lean body mass (LBM). LBM significantly improved in all exercise groups ( ≤ 0.043); however only HIT&P and HVHIT differ significantly from control ( ≤ 0.002). HIT diverges significantly from HIT&P ( = 0.017) and nonsignificantly from HVHIT ( = 0.059), while no differences were observed for HIT&P versus HVHIT ( = 0.691). In conclusion, moderate to high protein supplementation significantly increases the effects of a HIT-protocol on LBM in middle-aged untrained males.
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http://dx.doi.org/10.1155/2017/3619398DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5471590PMC
March 2018

Relationship between low tube voltage (70 kV) and the iodine delivery rate (IDR) in CT angiography: An experimental in-vivo study.

PLoS One 2017 20;12(3):e0173592. Epub 2017 Mar 20.

MR and CT Contrast Media Research, Bayer Healthcare, Berlin, Germany.

Objective: Very short acquisition times and the use of low-kV protocols in CTA demand modifications in the contrast media (CM) injection regimen. The aim of this study was to optimize the use of CM delivery parameters in thoraco-abdominal CTA in a porcine model.

Materials And Methods: Six pigs (55-68 kg) were examined with a dynamic CTA protocol (454 mm scan length, 2.5 s temporal resolution, 70 s total acquisition time). Four CM injection protocols were applied in a randomized order. 120 kV CTA protocol: (A) 300 mg iodine/kg bodyweight (bw), IDR = 1.5 g/s (flow = 5 mL/s), injection time (ti) 12 s (60 kg bw). 70 kV CTA protocols: 150 mg iodine/kg bw: (B) IDR = 0.75 g/s (flow = 2.5 mL/s), ti = 12 s (60 kg bw); (C) IDR = 1.5 g/s (flow = 5 mL/s), ti = 12 s (60 kg bw); (D) IDR = 3.0 g/s (flow = 10 mL/s), ti = 3 s (60 kg bw). The complete CM bolus shape was monitored by creating time attenuation curves (TAC) in different vascular territories. Based on the TAC, the time to peak (TTP) and the peak enhancement were determined. The diagnostic window (relative enhancement > 300 HU), was calculated and compared to visual inspection of the corresponding CTA data sets.

Results: The average relative arterial peak enhancements after baseline correction were 358.6 HU (A), 356.6 HU (B), 464.0 HU (C), and 477.6 HU (D). The TTP decreased with increasing IDR and decreasing ti, protocols A and B did not differ significantly (systemic arteries, p = 0.843; pulmonary arteries, p = 0.183). The delay time for bolus tracking (trigger level 100 HU; target enhancement 300 HU) for single-phase CTA was comparable for protocol A and B (3.9, 4.3 s) and C and D (2.4, 2.0 s). The scan window time frame was comparable for the different protocols by visual inspection of the different CTA data sets and by analyzing the TAC.

Conclusions: All protocols provided sufficient arterial enhancement. The use of a 70 kV CTA protocol is recommended because of a 50% reduction of total CM volume and a 50% reduced flow rate while maintaining the bolus profile. In contrast to pulmonary arterial enhancement, the systemic arterial enhancement improved only slightly increasing the IDR from 1.5 g/s to 3 g/s because of bolus dispersion of the very short bolus (3s) in the lungs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173592PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5358883PMC
August 2017

Radiation dose reduction in parasinus CT by spectral shaping.

Neuroradiology 2017 Feb 16;59(2):169-176. Epub 2017 Jan 16.

Department of Radiology, University Hospital Erlangen, Maximiliansplatz 1, 91054, Erlangen, Germany.

Introduction: Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT.

Methods: All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs). One hundred consecutive patients were prospectively enrolled and randomly assigned to the study or control group. All patients signed written informed consent. The study protocol was approved by the local Institutional Review Board and applies to the HIPAA. Subjective and objective image quality (attenuation values, image noise, and contrast-to-noise ratio (CNR)) were assessed. Radiation exposure was assessed as volumetric CT dose index, and effective dose was estimated. Mann-Whitney U test was performed for radiation exposure and for image noise comparison.

Results: All scans were of diagnostic image quality. Image noise in air, in the retrobulbar fat, and in the eye globe was comparable between both groups (all p > 0.05). CNR did not differ significantly between both groups (p = 0.7). Radiation exposure (1.7 vs. 2.1 mGy, p < 0.01) and effective dose (0.055 vs. 0.066 mSv, p < 0.01) were significantly reduced in the study group.

Conclusion: Radiation dose can be further reduced by 17% for low-dose parasinus CT by tin prefiltration maintaining diagnostic image quality.
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http://dx.doi.org/10.1007/s00234-016-1780-0DOI Listing
February 2017

Impact of whole body electromyostimulation on cardiometabolic risk factors in older women with sarcopenic obesity: the randomized controlled FORMOsA-sarcopenic obesity study.

Clin Interv Aging 2016 18;11:1697-1706. Epub 2016 Nov 18.

Institute of Medical Physics, Faculty of Medicine, Friedrich-Alexander University of Erlangen-Nürnberg.

Background: Sarcopenic obesity (SO) is characterized by a combination of low muscle and high fat mass with an additive negative effect of both conditions on cardiometabolic risk. The aim of the study was to determine the effect of whole-body electromyostimulation (WB-EMS) on the metabolic syndrome (MetS) in community-dwelling women aged ≥70 years with SO.

Methods: The study was conducted in an ambulatory university setting. Seventy-five community-dwelling women aged ≥70 years with SO living in Northern Bavaria, Germany, were randomly allocated to either 6 months of WB-EMS application with (WB-EMS&P) or without (WB-EMS) dietary supplementation (150 kcal/day, 56% protein) or a non-training control group (CG). WB-EMS included one session of 20 min (85 Hz, 350 μs, 4 s of strain-4 s of rest) per week with moderate-to-high intensity. The primary study endpoint was the MetS Z-score with the components waist circumference (WC), mean arterial pressure (MAP), triglycerides, fasting plasma glucose, and high-density lipoprotein cholesterol (HDL-C); secondary study endpoints were changes in these determining variables.

Results: MetS Z-score decreased in both groups; however, changes compared with the CG were significant (=0.001) in the WB-EMS&P group only. On analyzing the components of the MetS, significant positive effects for both WB-EMS groups (≤0.038) were identified for MAP, while the WB-EMS group significantly differed for WC (=0.036), and the WB-EMS&P group significantly differed for HDL-C (=0.006) from the CG. No significant differences were observed between the WB-EMS groups.

Conclusion: The study clearly confirms the favorable effect of WB-EMS application on the MetS in community-dwelling women aged ≥70 years with SO. However, protein-enriched supplements did not increase effects of WB-EMS alone. In summary, we considered this novel technology an effective and safe method to prevent cardiometabolic risk factors and diseases in older women unable or unwilling to exercise conventionally.
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http://dx.doi.org/10.2147/CIA.S116430DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5123721PMC
March 2017

Chronic recurrent multifocal osteomyelitis in association with pyoderma gangraenosum.

BMC Oral Health 2016 Sep 1;16(1):85. Epub 2016 Sep 1.

Department of Oral and Maxillofacial Surgery, University of Erlangen-Nürnberg, Glückstrasse 11, 91054, Erlangen, Germany.

Background: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare acquired inflammatory skeletal disorder of unknown origin. CRMO was first described by Gideon in 1972 and mainly affects children and young adults of female gender. The CRMO is part of the clinical picture of non-bacterial Osteomyelitis (NBO) and typically presents a relapsing recurring course with both remission and spontaneous exacerbation. CRMO is typically encountered in the limbs and the metaphysis of long bones in particular. Usually the clinical symptoms include painful swellings of the affected regions. This case report describes the rare case of a CRMO of the mandible in association with pyoderma gangraenosum.

Case Presentation: A 14-year old female caucasian patient, residing in the south of Germany, presented in the oncological outpatient clinic of our Department of Paediatrics and Adolescent Medicine in June 2014 complaining of increasing neck pain and progressive swelling at her left cheek ongoing for about 6 weeks. These symptoms had been occurring quarterly for 4 years, but had never been as pronounced. Blood biochemistry showed a moderately elevated CRP (35 mg/l) and a significantly increased blood sedimentation rate (BSR 48/120 mm). The panoramic radiograph, however, revealed a bone alteration in the left mandibular region. Further investigations confirmed the diagnosis of CRMO.

Conclusion: The present case underlines the fact that rare diseases might occasionally present with even more rare symptoms. These occasions can obviously be considered to present a considerable diagnostic challenge.
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http://dx.doi.org/10.1186/s12903-016-0275-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009688PMC
September 2016
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