Publications by authors named "Patric Kröpil"

70 Publications

Impact of standardized computed tomographic angiography for minimally invasive mitral and tricuspid valve surgery.

J Cardiothorac Surg 2021 Mar 20;16(1):34. Epub 2021 Mar 20.

Department of Cardiac Surgery, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany.

Background: Femoral cannulation for extracorporeal circulation (ECC) is a standard procedure for minimally invasive cardiac surgery (MICS) of the atrio-ventricular valves. Vascular pathologies may cause serious complications. Preoperative computed tomography-angiography (CT-A) of the aorta, axillary and iliac arteries was implemented at our department.

Methods: Between July 2017 and December 2018 all MICS were retrospectively reviewed (n = 143), and divided into 3 groups.

Results: In patients without CT (n = 45, 31.5%) ECC was applied via femoral arteries (91.1% right, 8.9% left). Vascular related complications (dissection, stroke, coronary and visceral ischemia, related in-hospital death) occurred in 3 patients (6.7%). In patients with non-contrast CT (n = 35, 24.5%) only femoral cannulation was applied (94.3% right) with complications in 4 patients (11.4%). CT-angiography (n = 63, 44.1%) identified 12 patients (19.0%) with vulnerable plaques, 7 patients (11.1%) with kinking of iliac vessels, 41 patients (65.1%) with multiple calcified plaques and 5 patients (7.9%) with small femoral artery diameter (d ≤ 6 mm). In 7 patients (11.1%) pathologic findings led to alternative cannulation via right axillary artery, additional 4 patients (6.3%) were cannulated via left femoral artery. Only 2 patients (3.2%) suffered from complications.

Conclusions: CT-A identifies vascular pathologies otherwise undetectable in routine preoperative preparation. A standardized imaging protocol may help to customize the operative strategy.
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http://dx.doi.org/10.1186/s13019-021-01400-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7981880PMC
March 2021

Is the prediction of one or two ipsilateral positive lymph nodes by computerized tomography and ultrasound reliable enough to restrict therapeutic neck dissection in oral squamous cell carcinoma (OSCC) patients?

J Cancer Res Clin Oncol 2021 Feb 1. Epub 2021 Feb 1.

Department of Oral and Maxillofacial Surgery, Medical Faculty, University Hospital of the Heinrich-Heine-University, Düsseldorf, Germany.

Introduction: Proper management of the clinically involved neck in OSCC patients continues to be a matter of debate. Our aim was to analyze the accuracy of computerized tomography (CT) and ultrasound (US) in anticipating the exact location of lymph node (LN) metastases of OSCC patients across the AAO-HNS (American Academy of Otolaryngology-Head and Neck Surgery) levels ipsi- and contralaterally. Furthermore, we wanted to assess the suitability of therapeutic selective neck dissection (SND) in patients with one or two ipsilateral positive nodes upon clinical staging (cN1/cN2a and cN2b(2/x) patients).

Methods: We prospectively analyzed the LN status of patients with primary OSCC using CT and US from 2007 to 2013. LNs were individually assigned to a map containing the AAO-HNS levels; patients bearing a single or just two ipsilateral positive nodes (designated cN1/cN2a or cN2b(2/x) patients either by CT (CT group) or US alone (US group) or in a group combining findings of CT and US (CTUS group)) received an ipsi-ND (I-V) and a contra-ND (I-IV). 78% of the LNs were sent individually for routine histopathological examination; the remaining were dissected and analyzed per neck level.

Results: Upon the analysis of 1.670 LNs of 57 patients, the exact location of pathology proven LN metastases in cN1 patients was more precisely predicted by US compared to CT with confirmed findings only in levels IA, IB und IIA. Clearly decreasing the number of missed lesions, the findings in the CTUS group nearly kept the spatial reliability of the US group. The same analysis for patients with exactly two supposed ipsilateral lesions (cN2b(2/x)) yielded confirmed metastases from levels I to V for both methods individually and in combination and, therefore, render SND insufficient for these cases.

Conclusion: Our findings stress the importance of conducting both, CT and US, in patients with primary OSCC. Only the combination of their findings warrants the application of therapeutic SND in patients with a single ipsilateral LN metastasis (cN1/cN2a patients) but not in patients with more than one lesion upon clinical staging (≥ cN2b).
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http://dx.doi.org/10.1007/s00432-021-03523-8DOI Listing
February 2021

Human iPSC-derived iMSCs improve bone regeneration in mini-pigs.

Bone Res 2019 24;7:32. Epub 2019 Oct 24.

2Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich Heine University, Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany.

Autologous bone marrow concentrate (BMC) and mesenchymal stem cells (MSCs) have beneficial effects on the healing of bone defects. To address the shortcomings associated with the use of primary MSCs, induced pluripotent stem cell (iPSC)-derived MSCs (iMSCs) have been proposed as an alternative. The aim of this study was to investigate the bone regeneration potential of human iMSCs combined with calcium phosphate granules (CPG) in critical-size defects in the proximal tibias of mini-pigs in the early phase of bone healing compared to that of a previously reported autograft treatment and treatment with a composite made of either a combination of autologous BMC and CPG or CPG alone. iMSCs were derived from iPSCs originating from human fetal foreskin fibroblasts (HFFs). They were able to differentiate into osteoblasts in vitro, express a plethora of bone morphogenic proteins (BMPs) and secrete paracrine signaling-associated cytokines such as PDGF-AA and osteopontin. Radiologically and histomorphometrically, HFF-iMSC + CPG transplantation resulted in significantly better osseous consolidation than the transplantation of CPG alone and produced no significantly different outcomes compared to the transplantation of autologous BMC + CPG after 6 weeks. The results of this translational study imply that iMSCs represent a valuable future treatment option for load-bearing bone defects in humans.
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http://dx.doi.org/10.1038/s41413-019-0069-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6813363PMC
October 2019

Relevance of Leaflet Prolapse to the Indication Policy for Aortic Valve-Sparing Root Replacement.

Heart Surg Forum 2019 06 3;22(3):E241-E246. Epub 2019 Jun 3.

Department of Cardiovascular Surgery, University Hospital, Dusseldorf, Germany.

Background: In aortic root replacement, "preexisting" or "induced" aortic leaflet prolapse is related to advanced aortic root pathology and can indicate valve repair. Efforts should be made to perform root replacement before leaflet prolapse is in its maximum extent.

Materials And Methods: Thirty-nine patients with chronic aortic root dilatation and aortic valve regurgitation (AR) underwent a reimplantation procedure. Contrary to 32 of the 39 patients (group A), 7 of the 39 patients (group B) underwent cusp plication for prolapse. For both groups, data related to the diameter at the level of maximal tubular extension, sinotubular junction, sinus of Valsalva, aorto-ventricular junction (AVJ), and aortic annulus were obtained from preoperative computed tomography scans and analyzed comparatively.

Results: Group B showed a higher mean AR grade (P = .007), a higher mean diameter at the level of the aortic annulus (P = .038), AVJ (P = .037), and aortic sinus (P <.001) and a higher sinus dilatation index (existing-to-predicted diameter ratio) (P <.001) than group A. The sinus of Valsalva displayed the best predictive value regarding a plicature-indicating prolapse (P <.001; 95% confidence interval [CI]: 0.809-1.013). A diameter >40 mm was accompanied by an odds ratio (OR) of 24.6 (95% CI: 1.29-496.02). During the follow-up period of 29.0 ± 18.4 months (range: 6-62 months), 1 patient (group A) required reoperation 5 years postoperatively for progressive AR.

Conclusion: The sinus of Valsalva diameter seems to have the greatest prognostic value for the development of prolapse. Our data suggest that root repair should be considered earlier in time before leaflet prolapse is complete, which most likely occurs when root dilatation becomes an aneurysm.
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http://dx.doi.org/10.1532/hsf.2201DOI Listing
June 2019

Potential of a machine-learning model for dose optimization in CT quality assurance.

Eur Radiol 2019 Jul 19;29(7):3705-3713. Epub 2019 Feb 19.

Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225, Dusseldorf, Germany.

Objectives: To evaluate machine learning (ML) to detect chest CT examinations with dose optimization potential for quality assurance in a retrospective, cross-sectional study.

Methods: Three thousand one hundred ninety-nine CT chest examinations were used for training and testing of the feed-forward, single hidden layer neural network (January 2016-December 2017, 60% male, 62 ± 15 years, 80/20 split). The model was optimized and trained to predict the volumetric computed tomography dose index (CTDI) based on scan patient metrics (scanner, study description, protocol, patient age, sex, and water-equivalent diameter (D)). The root mean-squared error (RMSE) was calculated as performance measurement. One hundred separate, consecutive chest CTs were used for validation (January 2018, 60% male, 63 ± 16 years), independently reviewed by two blinded radiologists with regard to dose optimization, and used to define an optimal cutoff for the model.

Results: RMSE was 1.71, 1.45, and 1.52 for the training, test, and validation dataset, respectively. The scanner and D were the most important features. The radiologists found dose optimization potential in 7/100 of the validation cases. A percentage deviation of 18.3% between predicted and actual CTDI was found to be the optimal cutoff: 8/100 cases were flagged as suboptimal by the model (range 18.3-53.2%). All of the cases found by the radiologists were identified. One examination was flagged only by the model.

Conclusions: ML can comprehensively detect CT examinations with dose optimization potential. It may be a helpful tool to simplify CT quality assurance. CT scanner and D were most important. Final human review remains necessary. A threshold of 18.3% between the predicted and actual CTDI seems adequate for CT quality assurance.

Key Points: • Machine learning can be integrated into CT quality assurance to improve retrospective analysis of CT dose data. • Machine learning may help to comprehensively detect dose optimization potential in chest CT, but an individual review of the results by an experienced radiologist or radiation physicist is required to exclude false-positive findings.
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http://dx.doi.org/10.1007/s00330-019-6013-6DOI Listing
July 2019

Noise insertion in CT for cocaine body packing: where is the limit of extensive dose reduction?

Eur J Med Res 2018 Dec 7;23(1):59. Epub 2018 Dec 7.

Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany.

Background: To evaluate the detection rate and image quality in CT-body-packer-screening at different radiation-dose levels and to determine a dose threshold that enables a reliable detection of incorporated body packs and incidental findings with a maximum of dose saving.

Materials And Methods: We retrospectively included 27 individuals who underwent an abdominal CT with automated exposure control due to suspected body packing. CT images were reconstructed at different radiation-dose levels of 50%, 10, 5% and 1% using iterative reconstructions. All 135 CT reconstructions were evaluated by three independent readers. Reviewers determined the presence of foreign bodies and evaluated the image quality using a 5-point ranking scale. In addition, visualization of incidental findings was assessed.

Results: A threshold of 5% (effective dose 0.11 ± 0.07 mSv) was necessary to correctly identify all 27 patients with suspected body packing. Extensive noise insertion to a dose level of 1% (0.02 ± 0.01 mSV) led to false-positive solid cocaine findings in three patients. Image quality was comparable between 100 and 50%. The threshold for correct identification of incidental findings was 10% of the initial dose (effective dose 0.21 ± 0.13 mSv).

Conclusions: Our results indicate that dose of abdominal CT for the detection of intracorporeal cocaine body packets can be markedly reduced to up to 5% of the initial dose while still providing sufficient image quality to detect ingested body packets. However, a minimum effective dose of 0.21 mSv (10% of initial dose) seems to be required to properly identify incidental findings.
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http://dx.doi.org/10.1186/s40001-018-0356-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6284291PMC
December 2018

Performance and clinical impact of machine learning based lung nodule detection using vessel suppression in melanoma patients.

Clin Imaging 2018 Nov - Dec;52:328-333. Epub 2018 Sep 11.

University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Germany.

Purpose: To evaluate performance and the clinical impact of a novel machine learning based vessel-suppressing computer-aided detection (CAD) software in chest computed tomography (CT) of patients with malignant melanoma.

Materials And Methods: We retrospectively included consecutive malignant melanoma patients with a chest CT between 01/2015 and 01/2016. Machine learning based CAD software was used to reconstruct additional vessel-suppressed axial images. Three radiologists independently reviewed a maximum of 15 lung nodules per patient. Vessel-suppressed reconstructions were reviewed independently and results were compared. Follow-up CT examinations and clinical follow-up were used to assess the outcome. Impact of additional nodules on clinical management was assessed.

Results: In 46 patients, vessel-suppressed axial images led to the detection of additional nodules in 25/46 (54.3%) patients. CT or clinical follow up was available in 25/25 (100%) patients with additionally detected nodules. 2/25 (8%) of these patients developed new pulmonary metastases. None of the additionally detected nodules were found to be metastases. None of the lung nodules detected by the radiologists was missed by the CAD software. The mean diameter of the 92 additional nodules was 1.5 ± 0.8 mm. The additional nodules did not affect therapeutic management. However, in 14/46 (30.4%) of patients the additional nodules might have had an impact on the radiological follow-up recommendations.

Conclusion: Machine learning based vessel suppression led to the detection of significantly more lung nodules in melanoma patients. Radiological follow-up recommendations were altered in 30% of the patients. However, all lung nodules turned out to be non-malignant on follow-up.
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http://dx.doi.org/10.1016/j.clinimag.2018.09.001DOI Listing
January 2019

Pulmonale Komplikationen bei Leptospirose: Selten, aber potentiell letal – die Bedeutung des Röntgen-Thorax.

Rofo 2018 Sep 5;190(9):861-862. Epub 2018 Apr 5.

University Dusseldorf, Medical Faculty, Division of Cardiology, Pulmonology and Vascular Medicine, D-40225 Dusseldorf, Germany.

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http://dx.doi.org/10.1055/a-0591-4137DOI Listing
September 2018

Tailoring CT Dose to Patient Size: Implementation of the Updated 2017 ACR Size-specific Diagnostic Reference Levels.

Acad Radiol 2018 12 23;25(12):1624-1631. Epub 2018 Mar 23.

University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstraße 5, 40225 Dusseldorf, Germany.

Rationale And Objectives: To use an automatic computed tomography (CT) dose monitoring system to analyze the institutional chest and abdominopelvic CT dose data as regards the updated 2017 American College of Radiology (ACR) diagnostic reference levels (DRLs) based on water-equivalent diameter (Dw) and size-specific dose estimates (SSDE) to detect patient-size subgroups in which CT dose can be optimized.

Materials And Methods: All chest CT examinations performed between July 2016 and April 2017 with and without contrast material, CT of the pulmonary arteries, and abdominopelvic CT with and without contrast material were included in this retrospective study. Dw and SSDE were automatically calculated for all scans using a previously validated in-house developed Matlab software and stored into our CT dose monitoring system. CT dose data were analyzed as regards the updated ACR DRLs (size groups: 21-25 cm, 25-29 cm, 29-33 cm, 33-37 cm, 37-41 cm). SSDE and volumetric computed tomography dose index (CTDIvol) were used as CT dose parameter.

Results: Overall, 30,002 CT examinations were performed in the study period, 3860 of which were included in the analysis (mean age 62.1 ± 16.4 years, Dw 29.0 ± 3.3 cm; n = 577 chest CT without contrast material, n = 628 chest CT with contrast material, n = 346 CT of chest pulmonary, n = 563 abdominopelvic CT without contrast material, n = 1746 abdominopelvic CT with contrast material). Mean SSDE and CTDIvol relative to the updated DRLs were 43.3 ± 26.4 and 45.1 ± 27.9% for noncontrast chest CT, 52.3 ± 23.1 and 52.0 ± 23.1% for contrast-enhanced chest CT, 68.8 ± 29.5 and 70.0 ± 31.0% for CT of pulmonary arteries, 41.9 ± 29.2 and 43.3 ± 31.3% for noncontrast abdominopelvic CT, and 56.8 ± 22.2 and 58.8 ± 24.4% for contrast-enhanced abdominopelvic CT. Lowest dose compared to the DRLs was found for the Dw group of 21-25 cm in noncontrast abdominopelvic CT (SSDE 30.4 ± 21.8%, CTDIvol 30.8 ± 21.4%). Solely the group of patients with a Dw of 37-41 cm undergoing noncontrast abdominopelvic CT exceeded the ACR DRL (SSDE 100.3 ± 59.0%, CTDIvol 107.1 ± 63.5%).

Conclusions: On average, mean SSDE and CTDIvol of our institutional chest and abdominopelvic CT protocols were lower than the updated 2017 ACR DRLs. Size-specific subgroup analysis revealed a wide variability of SSDE and CTDIvol across CT protocols and patient size groups with a transgression of DRLs in noncontrast abdominopelvic CT of large patients (Dw 37-41 cm).
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http://dx.doi.org/10.1016/j.acra.2018.03.005DOI Listing
December 2018

Heparin-bonded stent graft treatment for major visceral arterial injury after upper abdominal surgery.

Eur Radiol 2018 Aug 26;28(8):3221-3227. Epub 2018 Feb 26.

Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, 40225, Dusseldorf, Germany.

Purpose: To analyse technical success, complications, and short- and intermediate-term outcomes after heparin-bonded stent graft implantation for the treatment of major abdominal vessel injury after upper abdominal surgery.

Methods: This retrospective, IRB-approved analysis included 29 consecutive patients (female: n = 6, male: n = 23, mean age 65.9 ± 11.2 years). All patients underwent angiography and attempted heparin-bonded stent-graft implantation because of a major visceral arterial injury after upper abdominal surgery. Electronic clinical records, angiographic reports and imaging datasets were reviewed to assess technical success and complications. Telephone interviews were performed to obtain follow-up information and to estimate short- (> 30 days) and intermediate-term (> 90 days) outcomes.

Results: Successful stent graft placement was achieved in 82.8% (24/29). Peri-interventional complications were observed in 20.7% (6/29) and delayed, angiography-associated complications were observed in 34.5% (10/29) of the patients. Symptomatic re-bleeding occurred in 24.1% (7/29). Short-term survival (> 30 days) was 72.4% (21/29). Intermediate survival (> 90 days) was 37.9% (11/29).

Conclusion: Treatment of major vascular injuries with heparin-bonded stent grafts is feasible with a high technical success rate. However, survival depends on the underlying surgical condition, making interdisciplinary patient management mandatory.

Key Points: • Stent graft implantation is challenging, but has a high technical success rate. • Complications are frequent but surgical conversion is rarely necessary. • Survival depends on the underlying surgical condition causing the vascular injury. • Interdisciplinary management is crucial for the survival of these patients.
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http://dx.doi.org/10.1007/s00330-017-5288-8DOI Listing
August 2018

Institutional computed tomography diagnostic reference levels based on water-equivalent diameter and size-specific dose estimates.

J Radiol Prot 2018 Jun 20;38(2):536-548. Epub 2017 Dec 20.

University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Düsseldorf, Germany.

Size-specific institutional diagnostic reference levels (DRLs) were generated for chest and abdominopelvic computed tomography (CT) based on size-specific dose estimates (SSDEs) and depending on patients' water-equivalent diameter (Dw). 1690 CT examinations were included in the IRB-approved retrospective study. SSDEs based on the mean water-equivalent diameter of the entire scan volume were calculated automatically. SSDEs were analyzed for different patient sizes and institutional DRLs (iDRLS; 75% percentiles) based on Dw and SSDEs were generated. iDRLs were compared to the national DRLs. Mean volumetric computed tomography dose index (CTDIvol), Dw and SSDEs for all 1690 CT examinations were 7.2 ± 4.0 mGy (0.84-47.9 mGy), 29.0 ± 3.4 cm and 8.5 ± 3.8 mGy (1.2-37.7 mGy), respectively. Overall, the mean SSDEs of all CT examinations were higher than the CTDIvol in chest CT, abdominopelvic CT and upper abdominal CT, respectively (p < 0.001 for all). There was a strong linear correlation between Dw and SSDEs in chest (R = 0.66), abdominopelvic (R = 0.98) and upper abdominal CT (R = 0.96) allowing for the implementation of size-specific institutional DRLs based on SSDEs and patients' Dw. We generated size-specific, Dw-dependent institutional DRLs based on SSDEs, which allow for easier and more comprehensive analyses of CT radiation exposure. Our results indicate that implementation of SSDEs into national DRLs may be beneficial.
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http://dx.doi.org/10.1088/1361-6498/aaa32cDOI Listing
June 2018

Accuracy of Size-Specific Dose Estimate Calculation from Center Slice in Computed Tomography.

Radiat Prot Dosimetry 2018 02;178(3):343

Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany.

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http://dx.doi.org/10.1093/rpd/ncx119DOI Listing
February 2018

Iterative metal artefact reduction (MAR) in postsurgical chest CT: comparison of three iMAR-algorithms.

Br J Radiol 2017 Nov 22;90(1079):20160778. Epub 2017 Aug 22.

1 Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Dusseldorf, Germany.

Objectives: The purpose of this study was to evaluate the impact of three novel iterative metal artefact (iMAR) algorithms on image quality and artefact degree in chest CT of patients with a variety of thoracic metallic implants.

Methods: 27 postsurgical patients with thoracic implants who underwent clinical chest CT between March and May 2015 in clinical routine were retrospectively included. Images were retrospectively reconstructed with standard weighted filtered back projection (WFBP) and with three iMAR algorithms (iMAR-Algo1 = Cardiac algorithm, iMAR-Algo2 = Pacemaker algorithm and iMAR-Algo3 = ThoracicCoils algorithm). The subjective and objective image quality was assessed.

Results: Averaged over all artefacts, artefact degree was significantly lower for the iMAR-Algo1 (58.9 ± 48.5 HU), iMAR-Algo2 (52.7 ± 46.8 HU) and the iMAR-Algo3 (51.9 ± 46.1 HU) compared with WFBP (91.6 ± 81.6 HU, p < 0.01 for all). All iMAR reconstructed images showed significantly lower artefacts (p < 0.01) compared with the WFPB while there was no significant difference between the iMAR algorithms, respectively. iMAR-Algo2 and iMAR-Algo3 reconstructions decreased mild and moderate artefacts compared with WFBP and iMAR-Algo1 (p < 0.01).

Conclusion: All three iMAR algorithms led to a significant reduction of metal artefacts and increase in overall image quality compared with WFBP in chest CT of patients with metallic implants in subjective and objective analysis. The iMARAlgo2 and iMARAlgo3 were best for mild artefacts. IMARAlgo1 was superior for severe artefacts. Advances in knowledge: Iterative MAR led to significant artefact reduction and increase image-quality compared with WFBP in CT after implementation of thoracic devices. Adjusting iMAR-algorithms to patients' metallic implants can help to improve image quality in CT.
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http://dx.doi.org/10.1259/bjr.20160778DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5963368PMC
November 2017

ACCURACY OF SIZE-SPECIFIC DOSE ESTIMATE CALCULATION FROM CENTER SLICE IN COMPUTED TOMOGRAPHY.

Radiat Prot Dosimetry 2018 Jan;178(1):8-19

Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40 225 Düsseldorf, Germany.

To evaluate the accuracy of size-specific dose estimate (SSDE) calculation from center slice with water-equivalent diameter (Dw) and effective diameter (Deff). A total of 1812 CT exams (1583 adult and 229 pediatric) were included in this retrospective study. Dw and Deff were automatically calculated for all slices of each scan. SSDEs were calculated with two methods: (1) from the center slice; and (2) from all slices of the volume, which was regarded as the reference standard. Impact of patient weight, height and body mass index (BMI) on SSDE accuracy was assessed. The mean difference between overall SSDE and the center slice approach ranged from 2.0 ± 1.7% (range: 0-15.5%) for pediatric chest to 5.0 ± 3.2% (0-17.2%) for adult chest CT. Accuracy of the center slice SSDE approach correlated with patient size (BMI: r = 0.15-0.43; weight r = 0.26-0.49) which led to SSDE overestimation in small and underestimation in large patients. SSDE calculation using the center slice leads to an error of 2-5%; however, SSDE is underestimated in large patients and overestimation in small patients.
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http://dx.doi.org/10.1093/rpd/ncx069DOI Listing
January 2018

Optimizing radiation exposure in screening of body packing: image quality and diagnostic acceptability of an 80 kVp protocol with automated tube current modulation.

Forensic Sci Med Pathol 2017 Jun 7;13(2):145-150. Epub 2017 Mar 7.

Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Moorenstr 5, D-40225, Dusseldorf, Germany.

The aim of this study was to evaluate the objective and subjective image quality of a novel computed tomography (CT) protocol with reduced radiation dose for body packing with 80 kVp and automated tube current modulation (ATCM) compared to a standard body packing CT protocol. 80 individuals who were examined between March 2012 and July 2015 in suspicion of ingested drug packets were retrospectively included in this study. Thirty-one CT examinations were performed using ATCM and a fixed tube voltage of 80 kVp (group A). Forty-nine CT examinations were performed using a standard protocol with a tube voltage of 120 kVp and a fixed tube current time product of 40 mAs (group B). Subjective and objective image quality and visibility of drug packets were assessed. Radiation exposure of both protocols was compared. Contrast-to-noise ratio (group A: 0.56 ± 0.36; group B: 1.13 ± 0.91) and Signal-to-noise ratio (group A: 3.69 ± 0.98; group B: 7.08 ± 2.67) were significantly lower for group A compared to group B (p < 0.001). Subjectively, image quality was decreased for group A compared to group B (2.5 ± 0.8 vs. 1.2 ± 0.4; p < 0.001). Attenuation of body packets was higher with the new protocol (group A: 362.2 ± 70.3 Hounsfield Units (HU); group B: 210.6 ± 60.2 HU; p = 0.005). Volumetric Computed Tomography Dose Index (CTDIvol) and Dose Length Product (DLP) were significantly lower in group A (CTDIvol 2.2 ± 0.9 mGy, DLP 105.7 ± 52.3 mGycm) as compared to group B (CTDIvol 2.7 ± 0.1 mGy, DLP 126.0 ± 9.7 mGycm, p = 0.002 and p = 0.01). The novel 80 kVp CT protocol with ATCM leads to a significant dose reduction compared to a standard CT body packing protocol. The novel protocol led to a diagnostic image quality and cocaine body packets were reliably detected due to the high attenuation.
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http://dx.doi.org/10.1007/s12024-017-9848-7DOI Listing
June 2017

Contrast-Enhanced Computed Tomography in Intensive Care Unit Patients With Acute Clinical Deterioration: Impact of Hyperattenuating Adrenal Glands.

Can Assoc Radiol J 2017 Feb 20;68(1):21-26. Epub 2016 Dec 20.

Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstrasse 5, 40225, Dusseldorf, Germany.

Purpose: The study sought to assess the frequency and prognostic value of hyperattenuating adrenal glands on contrast-enhanced computed tomography (CT) scans of surgical intensive care unit (ICU) patients with acute clinical deterioration.

Methods: Eighty-eight consecutive ICU patients (63.2 ± 14.5 years of age) were included in this retrospective analysis. All patients underwent biphasic contrast-enhanced CT due to an acute clinical deterioration. Hyperattenuation of the adrenal glands was assessed subjectively and objectively. Subjective presence or absence of hyperattenuating adrenal glands was assessed by 2 blinded radiologists (J.B. and R.S.L.) in consensus. Hounsfield units (HU) were measured in the adrenal glands and in the inferior vena cava. Objective hyperattenuation was defined as HU (adrenal glands) > HU (inferior vena cava) with a 15-HU threshold. Death within 14 days following CT was set as endpoint and acquired from electronic patient data.

Results: Thirty-eight patients (43.2%, Group A) exhibited hyperattenuation of the adrenal glands, whereas 50 patients (56.8%, Group B) did not. Concerning the objective analysis, 31 patients (35.2%, Group A) exhibited hyperdense adrenal glands, whereas 53 patients (64.8%, Group B) did not. Overall 27 of 88 patients (30.6%) died within 14 days following the CT examination. Lethal outcome was significantly more frequent among patients in Group A and A (19 of 38 patients [50.0%] and 15 of 31 patients [48.4%]) as compared with patients in Group B (8 of 50 patients [16.0%]) and Group B (12 of 57 patients [21.1%]; P < .05). Subjective and objective analysis correlated significantly (P < .05).

Conclusions: Hyperattenuation of adrenal glands on contrast-enhanced CT of ICU patients with acute clinical deterioration is associated with a high mortality and might serve as a prognostic marker for patients' outcome.
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http://dx.doi.org/10.1016/j.carj.2016.07.006DOI Listing
February 2017

Intermuscular technique for implantation of the subcutaneous implantable cardioverter defibrillator: long-term performance and complications.

Europace 2017 Dec;19(12):2036-2041

City University London, Northampton Sq., London, UK.

Aims: The subcutaneous cardioverter defibrillator was designed to overcome electrode complications of transvenous defibrillation systems. While largely achieved, pocket complications have increased. Subcutaneous implantation of the pulse generator leaves it prone to erosion, extrusion, discomfort, and poor cosmesis.

Methods And Results: We use a demonstration electrode and pulse generator with fluoroscopy, prior to prepping and draping, to maximize the left ventricular mass between them. We adapted a submuscular abdominal ICD technique to implant the S-ICD intermuscularly between the anterior surface of serratus anterior and the posterior surface of latissimus dorsi. Surgery in our patients beyond the subcutaneous tissue was bloodless, as muscle layers were carefully separated but not incised, which also protected the long thoracic nerve. Two layers of muscle protect the pulse generator. We have implanted 82 consecutive patients with this technique, taking ∼65 min. All patients were converted with 65 J standard polarity shock during induced arrhythmia conversion testing, with six (7.3%) patients requiring a repositioning of the pulse generator prior to successful conversion. Seven spontaneous episodes of ventricular fibrillation were detected in three (3.6%) patients, all successfully converted back to sinus rhythm. Long-term patient outcomes have been good with low complication rates over the mean ± standard deviation 3.6 ± 1.2 years.

Conclusion: Our intermuscular technique and implant methodology is successful for placement of the subcutaneous defibrillator pulse generator. Our technique leads to an excellent cosmetic result and high levels of patient satisfaction. Rates of first shock conversion during defibrillation testing, inappropriate shocks, and complications during follow-up compare favourably with previous published case series. There were no left arm movement limitations post-operatively.
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http://dx.doi.org/10.1093/europace/euw297DOI Listing
December 2017

Metal Artifact Reduction in Computed Tomography After Deep Brain Stimulation Electrode Placement Using Iterative Reconstructions.

Invest Radiol 2017 Jan;52(1):18-22

From the *Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf; and †Computed Tomography, Siemens Healthcare GmbH, Forchheim, Germany.

Objectives: Diagnostic accuracy of intraoperative computed tomography (CT) after deep brain stimulation (DBS) electrode placement is limited due to artifacts induced by the metallic hardware, which can potentially mask intracranial postoperative complications. Different metal artifact reduction (MAR) techniques have been introduced to reduce artifacts from metal hardware in CT. The purpose of this study was to assess the impact of a novel iterative MAR technique on image quality and diagnostic performance in the follow-up of patients with DBS electrode implementation surgery.

Materials And Methods: Seventeen patients who had received routine intraoperative CT of the head after implantation of DBS electrodes between March 2015 and June 2015 were retrospectively included. Raw data of all patients were reconstructed with standard weighted filtered back projection (WFBP) and additionally with a novel iterative MAR algorithm. We quantified frequencies of density changes to assess quantitative artifact reduction. For evaluation of qualitative image quality, the visibility of numerous cerebral anatomic landmarks and the detectability of intracranial electrodes were scored according to a 4-point scale. Furthermore, artifact strength overall and adjacent to the electrodes was rated.

Results: Our results of quantitative artifact reduction showed that images reconstructed with iterative MAR (iMAR) contained significantly lower metal artifacts (overall low frequency values, 1608.6 ± 545.5; range, 375.5-3417.2) compared with the WFBP (overall low frequency values, 4487.3 ± 875.4; range, 2218.3-5783.5) reconstructed images (P < 0.004). Qualitative image analysis showed a significantly improved image quality for iMAR (overall anatomical landmarks, 2.49 ± 0.15; median, 3; range, 0-3; overall electrode characteristics, 2.35 ± 0.16; median, 2; range, 0-3; artifact characteristics, 2.16 ± 0.08; median, 2.5; range, 0-3) compared with WFBP (overall anatomical landmarks, 1.21 ± 0.64; median, 1; range, 0-3; overall electrode characteristics, 0.74 ± 0.37; median, 1; range, 0-2; artifact characteristics, 0.51 ± 0.15; median, 0.5; range, 0-2; P < 0.002).

Conclusions: Reconstructions of cranial CT images with the novel iMAR algorithm in patients after DBS implantation allows an efficient reduction of metal artifacts near DBS electrodes compared with WFBP reconstructions. We demonstrated an improvement of quantitative and qualitative image quality of iMAR compared with WFBP in patients with DBS electrodes.
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http://dx.doi.org/10.1097/RLI.0000000000000296DOI Listing
January 2017

Stent Lumen Visibility in Single-energy CT Angiography: Does Tube Potential Matter?

Acad Radiol 2016 06 6;23(6):752-9. Epub 2016 May 6.

Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40225 Dusseldorf, Germany.

Rationale And Objectives: There has been a trend toward lowering tube potential in computed tomography angiography (CTA) examinations to reduce radiation dose or contrast medium dose. The aim of this study was to evaluate the influence of tube potential on peripheral artery in-stent lumen visibility in CTA examinations.

Materials And Methods: Nine different peripheral artery stents were placed in a vessel phantom (inner diameter: 5 mm, surrounded by water) and scanned consecutively using a 128-row CT scanner with 70, 80, 100, 120, and 140 kV and two different concentrations of contrast medium to simulate contrast-enhanced blood. Medium-smooth and ultra-sharp reconstruction kernels with filtered back projection (B30f, B46f) and iterative reconstruction technique (I30f, I46f) were used. Visible in-stent lumen diameter and artifact width were evaluated using a semiautomatic software tool. All stents were scanned with digital angiography, which was regarded as the reference standard.

Results: Averaged over all stents, visible in-stent lumen diameter ranged from 1.30 ± 0.21 mm (CM2/70 kV/I30f) to 3.13 ± 0.32 mm (CM1/120 kV/I46f). In-stent lumen diameters were significantly higher for 120 and 140 kV compared to 70 kV (2.39 ± 0.73 and 2.39 ± 0.66 mm vs 1.99 ± 0.69 mm; P = 0.01 and P = 0.005). Ultra-sharp reconstruction kernels lead to significantly better in-stent lumen visibility than smooth reconstruction kernels (B46f: 2.74 ± 0.34 mm vs B30f: 1.57 ± 0.36 mm; P < 0.001, respectively). Furthermore, in-stent lumen visibility was improved for iterative reconstructions compared to filtered back projection (I46f: 2.93 ± 0.30 mm vs B46f: 2.74 ± 0.34 mm; P < 0.001). Contrast medium concentration did not influence in-stent lumen visibility.

Conclusions: Despite all known benefits of low kV CTA protocols, the use of a very low tube potential may hamper in-stent lumen visibility. A sharp kernel may be of value when evaluating the inner lumen of vascular stents.
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http://dx.doi.org/10.1016/j.acra.2016.03.012DOI Listing
June 2016

Comparison of Manual and Automated Preprocedural Segmentation Tools to Predict the Annulus Plane Angulation and C-Arm Positioning for Transcatheter Aortic Valve Replacement.

PLoS One 2016 13;11(4):e0151918. Epub 2016 Apr 13.

Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, Düsseldorf, Germany.

Background: Preprocedural manual multi-slice-CT-segmentation tools (MSCT-ST) define the gold standard for planning transcatheter aortic valve replacement (TAVR). They are able to predict the perpendicular line of the aortic annulus (PPL) and to indicate the corresponding C-arm angulation (CAA). Fully automated planning-tools and their clinical relevance have not been systematically evaluated in a real world setting so far.

Methods And Results: The study population consists of an all-comers cohort of 160 consecutive TAVR patients with a drop out of 35 patients for technical and anatomical reasons. 125 TAVR patients underwent preprocedural analysis by manual (M-MSCT) and fully automated MSCT-ST (A-MSCT). Method-comparison was performed for 105 patients (Cohort A). In Cohort A, CAA was defined for each patient, and accordance within 10° between M-MSCT and A-MSCT was considered adequate for concept-proof (95% in LAO/RAO; 94% in CRAN/CAUD). Intraprocedural CAA was defined by repetitive angiograms without utilizing the preprocedural measurements. In Cohort B, intraprocedural CAA was established with the use of A-MSCT (20 patients). Using preprocedural A-MSCT to indicate the corresponding CAA, the levels of contrast medium (ml) and radiation exposure (cine runs) were reduced in Cohort B compared to Cohort A significantly (23.3±10.3 vs. 35.3 ±21.1 ml, p = 0.02; 1.6±0.7 vs. 2.4±1.4 cine runs; p = 0.02) and trends towards more safety in valve-positioning could be demonstrated.

Conclusions: A-MSCT-analysis provides precise preprocedural information on CAA for optimal visualization of the aortic annulus compared to the M-MSCT gold standard. Intraprocedural application of this information during TAVR significantly reduces the levels of contrast and radiation exposure.

Trial Registration: ClinicalTrials.gov NCT01805739.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0151918PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4830561PMC
August 2016

Microparticle-Induced Coagulation Relates to Coronary Artery Atherosclerosis in Severe Aortic Valve Stenosis.

PLoS One 2016 24;11(3):e0151499. Epub 2016 Mar 24.

Division of Cardiology, Pulmonology, and Vascular Medicine, Medical Faculty, University Düsseldorf, Düsseldorf, Germany.

Background: Circulating microparticles (MPs) derived from endothelial cells and blood cells bear procoagulant activity and promote thrombin generation. Thrombin exerts proinflammatory effects mediating the progression of atherosclerosis. Aortic valve stenosis may represent an atherosclerosis-like process involving both the aortic valve and the vascular system. The aim of this study was to investigate whether MP-induced thrombin generation is related to coronary atherosclerosis and aortic valve calcification.

Methods: In a cross-sectional study of 55 patients with severe aortic valve stenosis, we assessed the coronary calcification score (CAC) as indicator of total coronary atherosclerosis burden, and aortic valve calcification (AVC) by computed tomography. Thrombin-antithrombin complex (TATc) levels were measured as a marker for thrombin formation. Circulating MPs were characterized by flow cytometry according to the expression of established surface antigens and by measuring MP-induced thrombin generation.

Results: Patients with CAC score below the median were classified as patients with low CAC, patients with CAC Score above the median as high CAC. In patients with high CAC compared to patients with low CAC we detected higher levels of TATc, platelet-derived MPs (PMPs), endothelial-derived MPs (EMPs) and MP-induced thrombin generation. Increased level of PMPs and MP-induced thrombin generation were independent predictors for the severity of CAC. In contrast, AVC Score did not differ between patients with high and low CAC and did neither correlate with MPs levels nor with MP-induced thrombin generation.

Conclusion: In patients with severe aortic valve stenosis MP-induced thrombin generation was independently associated with the severity of CAC but not AVC indicating different pathomechanisms involved in coronary artery and aortic valve calcification.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0151499PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807100PMC
August 2016

CT pulmonary angiography: simultaneous low-pitch dual-source acquisition mode with 70 kVp and 40 ml of contrast medium and comparison with high-pitch spiral dual-source acquisition with automated tube potential selection.

Br J Radiol 2016 Jun 23;89(1062):20151059. Epub 2016 Mar 23.

Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany.

Objective: To assess the feasibility of a 70-kVp CT pulmonary angiography (CTPA) protocol using simultaneous dual-source (SimDS) acquisition mode with 40 ml of contrast medium (CM) and comparison with a high-pitch spiral dual-source (SpiralDS) acquisition protocol with automated tube potential selection (ATPS).

Methods: Following the introduction of a new 70-kVp/40-ml SimDS-CTPA protocol in December 2014 for all patients with a body mass index (BMI) below 35 kg m(-2), the first 35 patients were retrospectively included in this study and assigned to Group A (BMI: 27 ± 4 kg m(-2), age: 66 ± 15 years). The last 35 patients with a BMI below 35 kg m(-2) who had received SpiralDS-CTPA with ATPS were included for comparison (Group B) (70 ml CM; BMI: 27 ± 4 kg m(-2), age: 68 ± 16 years). Subjective image quality (image quality) was assessed by two radiologists (from 1, non-diagnostic, to 4, excellent). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), volumetric CT dose index (CTDIvol), dose-length product (DLP) and effective dose were assessed.

Results: All examinations were of diagnostic image quality. Subjective image quality, SNR and CNR were comparable between Groups A and B (3.7 ± 0.6 vs 3.7 ± 0.5, 14.6 ± 6.0 vs 13.9 ± 3.7 and 12.4 ± 5.7 vs 11.6 ± 3.3, respectively; p > 0.05). CTDIvol, DLP and effective dose were significantly lower in Group A than in Group B (4.5 ± 1.6 vs 7.5 ± 2.1 mGy, 143.3 ± 44.8 vs 278.3 ± 79.44 mGy cm and 2.0 ± 0.6 vs 3.9 ± 1.1 mSv, respectively; p < 0.05).

Conclusion: 70-kVp SimDS-CTPA with 40 ml of CM is feasible and provides diagnostic image quality, while radiation dose and CM can be reduced by almost 50% and 40%, respectively, compared with a SpiralDS-CTPA protocol with ATPS.

Advances In Knowledge: 70-kVp SimDS-CTPA with 40 ml of CM is feasible in patients with a BMI up to 35 kg m(-2) and can help reduce radiation exposure and CM in these patients.
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http://dx.doi.org/10.1259/bjr.20151059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5258170PMC
June 2016

Metal artifact reduction (MAR) based on two-compartment physical modeling: evaluation in patients with hip implants.

Acta Radiol 2017 Jan 2;58(1):70-76. Epub 2016 Mar 2.

University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf, Germany.

Background: Artifacts from metallic implants can hinder image interpretation in computed tomography (CT). Image quality can be improved using metal artifact reduction (MAR) techniques.

Purpose: To evaluate the impact of a MAR algorithm on image quality of CT examinations in comparison to filtered back projection (FBP) in patients with hip prostheses.

Material And Methods: Twenty-two patients with 25 hip prostheses who underwent clinical abdominopelvic CT on a 64-row CT were included in this retrospective study. Axial images were reconstructed with FBP and five increasing MAR levels (M30-34). Objective artifact strength (OAS) (SI-SI) was assessed by region of interest (ROI) measurements in position of the strongest artifact (SI) and in an osseous structure without artifact (SI) (in Hounsfield units [HU]). Two independent readers evaluated subjective image quality regarding metallic hardware, delineation of bone, adjacent muscle, and pelvic organs on a 5-point scale (1, non-diagnostic; 5, excellent image quality). Artifacts in the near field, far field, and newly induced artifacts due to the MAR technique were analyzed.

Results: OAS values were: M34: 243.8 ± 155.4 HU; M33: 294.3 ± 197.8 HU; M32: 340.5 ± 210.1 HU; M31: 393.6 ± 225.2 HU; M30: 446.8 ± 224.2 HU and FBP: 528.9 ± 227.7 HU. OAS values were significantly lower for M32-34 compared to FBP (P < 0.01). For overall subjective image quality, results were: FBP, 2.0 ± 0.2; M30, 2.3 ± 0.8; M31, 2.6 ± 0.5; M32, 3.0 ± 0.6; M33, 3.5 ± 0.6; and M34, 3.8 ± 0.4 (P < 0.001 for M30-M34 vs. FBP, respectively). Increasing MAR levels resulted in new artifacts in 17% of reconstructions.

Conclusion: The investigated MAR algorithm led to a significant reduction of artifacts from metallic hip implants. The highest MAR level provided the least severe artifacts and the best overall image quality.
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http://dx.doi.org/10.1177/0284185116633911DOI Listing
January 2017

CT angiography of the aorta using 80 kVp in combination with sinogram-affirmed iterative reconstruction and automated tube current modulation: Effects on image quality and radiation dose.

J Med Imaging Radiat Oncol 2016 Apr 7;60(2):187-93. Epub 2016 Jan 7.

Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany.

Introduction: The objective of this study was to evaluate image quality and radiation dose of a CT angiography (CTA) protocol using 80 kVp in combination with iterative reconstruction and automated tube current modulation.

Methods: Ninety-five aortic CTA examinations were included in this study. A novel 80 kVp aortic CTA-protocol with iterative reconstruction was introduced in our department in March 2012 for patients with a body mass index (BMI) below 32 kg/m(2). The first 72 consecutive examinations were retrospectively assigned to group A (56 patients, 42 men, 14 women, mean age 69.6 ± 10.7 years, BMI range 19.7-31.1 kg/m(2)). For comparison, the last 23 consecutive examinations performed with the old protocol (100 kVp) were assigned to group B (21 patients, 13 men, 8 women, mean age 67.4 ± 11.1 years, BMI range 19.7-31.9 kg/m(2)). Thoracic and abdominal contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and aortic attenuation were assessed. Subjective image quality was rated on a 5-point scale (1 = non diagnostic; 5 = excellent). Furthermore, dose length product (DLP) and volumetric computed tomography dose index (CTDIvol) were analysed.

Results: All examinations achieved diagnostic image quality. Attenuation of the aorta was significantly higher in group A compared with B (thoracic: 443.5 ± 90.5 Hounsfield units (HU) vs. 296.0 ± 61.0 HU; abdominal: 426.3 ± 94.2 HU vs. 283.6 ± 60.5 HU; P < 0.05, respectively). CNR, SNR and subjective image quality were comparable between both groups (CNR: 12.8 ± 3.7 vs. 13.0 ± 7.4; SNR 14.4 ± 3.9 vs. 14.9 ± 8.2; subjective image quality: 4.3 ± 0.6 vs. 4.5 ± 0.6; P > 0.05, respectively). CTDIvol and DLP were significantly lower in group A (1.9 ± 0.5 mGy; 139.2 ± 41.1 mGy × cm) as compared with group B (4.2 ± 1.4 mGy; 292.1 ± 91.5 mGy × cm; P < 0.001, respectively).

Conclusion: Low-dose CTA of the aorta using 80 kVp with iterative reconstruction enables a significant dose reduction of up to 50% compared with a 100 kVp protocol in patients with a BMI below 32 kg/m(2) while diagnostic image quality is maintained.
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http://dx.doi.org/10.1111/1754-9485.12425DOI Listing
April 2016

Does body mass index outperform body weight as a surrogate parameter in the calculation of size-specific dose estimates in adult body CT?

Br J Radiol 2016 23;89(1059):20150734. Epub 2015 Dec 23.

University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.

Objective: To assess the value of body mass index (BMI) in comparison with body weight as a surrogate parameter for the calculation of size-specific dose estimates (SSDEs) in thoracoabdominal CT.

Methods: 401 CT examinations in 235 patients (196 chest, 205 abdomen; 95 females, 140 males; age 62.5 ± 15.0 years) were analysed in regard to weight, height and BMI (kg m(-2)). Effective diameter (Deff, cm) was assessed on axial CT images. The correlation between BMI, weight and Deff was calculated. SSDEs were calculated based on Deff, weight and BMI and lookup tables were developed.

Results: Overall height, weight, BMI and Deff were 172.5 ± 9.9 cm, 79.5 ± 19.1 kg, 26.6 ± 5.6 kg m(-2) and 30.1 ± 4.3 cm, respectively. There was a significant correlation between Deff and BMI as well as weight (r = 0.85 and r = 0.84; p < 0.05, respectively). Correlation was significantly better for BMI in abdominal CT (r = 0.89 vs r = 0.84; p < 0.05), whereas it was better for weight in chest CT (r = 0.87 vs r = 0.81; p < 0.05). Surrogated SSDEs did not differ significantly from the reference standard with a median absolute relative difference of 4.2% per patient (interquartile range 25-75: 3.1-7.89, range 0-25.3%).

Conclusion: BMI and weight exhibit a significant correlation with Deff in adult patients and can be used as surrogates in the calculation of SSDEs. Using the herein-developed lookup charts, SSDEs can be calculated based on patients' weight and BMI.

Advances In Knowledge: In abdominal CT, BMI has a superior correlation with effective diameter compared with weight, whereas weight is superior in chest CT. Patients' BMI and weight can be used as surrogates in the calculation of SSDEs.
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http://dx.doi.org/10.1259/bjr.20150734DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4986493PMC
July 2016

Diagnostic value of CT-localizer and axial low-dose computed tomography for the detection of drug body packing.

J Forensic Leg Med 2016 Jan 2;37:55-60. Epub 2015 Nov 2.

University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf, Germany.

Objectives: The purpose of this study was to assess the diagnostic performance of CT-localizers in the detection of intracorporal containers.

Methods: This study was approved by the research ethics committee of our clinic. From March 2012 to March 2013, 108 subjects were referred to our institute with suspected body packing. The CT-localizer and the axial CT-images were compared by two blinded observers retrospectively. Presence of body packs was assessed in consensus. Sensitivity and specificity, PPV and NPV of the CT-localizer were calculated.

Results: Packets were detected in the CT-localizer of 19 suspects. In 28 of 108 cases packs were detected in axial CT-images. Sensitivity of CT-localizer for detection of packs was 0.68, and specificity was 1.00. There were no cases rated as false positive. The PPV was 1.0 and the NPV was 0.89. The omission of the axial CT-images would have led to a mean radiation dose reduction of 1.94 ± 0.5 mSv.

Conclusions: The value of CT-localizers lies in their high PPV. Localizers are limited by low sensitivity, compared to axial CT-images in screening of potential body packers. However, in positive cases their high PPV may possibly allow to omit the complete axial abdominal CT to achieve even lower radiation exposure.
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http://dx.doi.org/10.1016/j.jflm.2015.10.009DOI Listing
January 2016

Value of 3D TEE for LAA Morphology.

JACC Cardiovasc Imaging 2015 Sep;8(9):1107-1110

Division of Cardiology, Pulmonology, and Vascular Medicine, Medical Faculty, University of Düsseldorf, Düsseldorf, Germany. Electronic address:

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http://dx.doi.org/10.1016/j.jcmg.2014.07.030DOI Listing
September 2015

Peritoneal sarcomatosis: site of origin for the establishment of an in vitro and in vivo cell line model to study therapeutic resistance in dedifferentiated liposarcoma.

Tumour Biol 2016 Feb 15;37(2):2341-51. Epub 2015 Sep 15.

Department of Surgery (A), Heinrich-Heine-University and University Hospital Duesseldorf, Moorenstr. 5, Bldg. 12.46, 40225, Duesseldorf, Germany.

Approximately 50-70 % of patients with retroperitoneal or intraabdominal sarcoma develop a relapse after surgical therapy, including peritoneal sarcomatosis, an extremely rare site of metastatic disease which is associated with an extremely poor prognosis. Accordingly, the establishment of a permanent cell line derived from peritoneal sarcomatosis might provide a helpful tool to understand the biological behavior and to develop new therapeutic strategies. Thus, we established and characterized a liposarcoma cell line (Lipo-DUE1) from a peritoneal sarcomatosis that was permanently cultured without showing any morphological changes. Lipo-DUE1 cells exhibited a spindle-shaped morphology and positive staining for S100. Tumorigenicity was demonstrated in vitro by invasion and migration assays and in vivo by using a subcutaneous xenograft mouse model. In addition, aCGH analysis revealed concordant copy number variations on chromosome 12q in the primary tumor, peritoneal sarcomatosis, and Lipo-DUE1 cells that are commonly observed in liposarcoma. Chemotherapeutic sensitivity assays revealed a pronounced drug-resistant phenotype of Lipo-DUE1 cells to conventionally used chemotherapeutic agents. In conclusion, we describe for the first time the establishment and characterization of a liposarcoma cell line derived from a peritoneal sarcomatosis. Hence, in the future, the newly established cell line Lipo-DUE1 might serve as a useful in vitro and in vivo model to investigate the biological behavior of liposarcoma and to assess novel targeted therapies.
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http://dx.doi.org/10.1007/s13277-015-4050-6DOI Listing
February 2016

Low-tube voltage 100 kVp MDCT in screening of cocaine body packing: image quality and radiation dose compared to 120 kVp MDCT.

Abdom Imaging 2015 Oct;40(7):2152-8

Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225, Dusseldorf, Germany.

Purpose: The aim of this study was to evaluate the impact of a reduced tube potential (100 kVp) for non-enhanced abdominal low-dose CT on radiation dose and image quality (IQ) in the detection of body packing.

Methods: This retrospective study was approved by the local research ethics committee of our clinic. From March 2012 to July 2014, 99 subjects were referred to our institute with suspected body packing. 50 CT scans were performed using a 120 kVp protocol (group A), and 49 CTs were performed using a low-dose protocol with a tube voltage of 100 kVp (group B). Subjective and objective IQ were assessed. DLP and CTDIvol were analyzed.

Results: All examinations were of diagnostic IQ. Objective IQ was not significantly different between the 120 kVp and 100 kVp protocol. Mean density of solid and liquid body packets was 210 ± 60.2 HU at 120 kVp and 250.6 ± 29.7 HU at 100 kVp. Radiation dose was significantly lower in group B as compared to group A (p < 0.05). In group A, body packs were detected in 16 (32%) of the 50 patients. In group B, packets were observed in 15 (31%) of 49 patients. Laboratory analysis detected cocaine in all smuggled body packs.

Conclusions: Low-tube voltage 100 kVp MDCT with automated tube current modulation in screening of illegal drugs leads to a diagnostic IQ and significant dose reduction compared to 120 kVp low-tube voltage protocols. Despite lower radiation dose, liquid and solid cocaine containers retain high attenuation and are easily detected.
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http://dx.doi.org/10.1007/s00261-015-0464-2DOI Listing
October 2015

Metastasized pancreatic carcinoma with neoadjuvant FOLFIRINOX therapy and R0 resection.

World J Gastroenterol 2015 May;21(20):6384-90

Sophie Schneitler, Dieter Häussinger, Dirk Graf, Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Düsseldorf, D-40225 Düsseldorf, Germany.

Patients with metastasized carcinoma of the pancreas have a very poor prognosis, and long-term survival cannot be expected. This case report describes two patients with an initial diagnosis of metastatic pancreatic cancer, both with hepatic metastases and one with an additional peritoneal carcinomatosis. Initially, both patients were treated intravenously with the FOLFIRINOX chemotherapy regimen, consisting of 5-FU, folinic acid, irinotecan and oxaliplatin. Surprisingly, the FOLFIRINOX treatment resulted in complete resolution of the hepatic metastases in both patients, with no lesions detectable by computed tomography scan. Furthermore, treatment response included decreased diameter of the primary tumor in the tail of the pancreas and disappearance of the additional peritoneal carcinomatosis. Both patients were discussed by our multidisciplinary tumor board, which recommended surgical resections of the carcinoma. The R0 resection of the primary tumor was successful in both cases and, interestingly, the resected tissues showed no evidence of the hepatic metastases intraoperatively. In the first case, the patient received a postoperative 6-mo course of adjuvant chemotherapy with gemcitabine. In the second case, the patient continued to receive the FOLFIRINOX regimen for an additional 6 mo postoperatively. At 12 mo after the operation, a nonresectable retroperitoneal lymph node metastasis was detected in the first patient, whereas the second patient remained in complete remission at the time of this report (5 mo after the adjuvant therapy was discontinued). This case report is the first of its kind to describe two cases of hepatic metastatic pancreatic carcinoma that were resectable following treatment with FOLFIRINOX. Further studies are required to examine the role of FOLFIRINOX as a neoadjuvant treatment option in subgroups of patients with initially metastasized pancreatic carcinoma.
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http://dx.doi.org/10.3748/wjg.v21.i20.6384DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4445117PMC
May 2015