Publications by authors named "Stefan O Schoenberg"

383 Publications

Dual-Energy CT Vital Iodine Tumor Burden for Response Assessment in Patients With Metastatic GIST Undergoing TKI Therapy: Comparison to Standard CT and FDG PET/CT Criteria.

AJR Am J Roentgenol 2021 Oct 20. Epub 2021 Oct 20.

Department of Radiology, Duke University Medical Center, Durham, North Carolina, United States of America.

CT-based criteria for assessing gastroinstestinal stromal tumor (GIST) response to tyroskine kinase inhibitor (TKI) therapy are limited partly because tumor attenuation is influenced by treatment-related changes including hemorrhage and calcification. Iodine concentration may be less impacted by such changes. To determine whether DECT vital iodine tumor burden (TB) provides improved differentiation between responders and non-responders in patients with metastatic GIST undergoing TKI therapy compared to established CT and PET/CT criteria. An anthropomorphic phantom with spherical inserts mimicking GIST lesions of varying iodine concentrations and having non-enhancing central necrotic cores underwent DECT to determine a threshold iodine concentration. Forty patients (median age 57 years; 25 women, 15 men) treated with TKI for metaststic GIST were retrospectively evaluated. Patients underwent baseline and follow-up DECT and FDG PET/CT. Response assessment was performed using RECIST 1.1, modified Choi (mChoi), vascular tumor burden (VTB), DECT vital iodine TB, and European Organization for Research and Treatment of Cancer (EORTC PET) criteria. DECT vital iodine TB used the same percentage changes as RECIST 1.1 response categories. Progression-free survival (PFS) was compared between responders and non-responders for each response criteria using Cox proportional hazard ratios and Harrell's c-indices. The phantom experiment identified a 0.5 mg/mL threshold to differentiate vital from non-vital tissue. Using DECT vital iodine TB, median PFS was significantly different between non-responders and responders (587 vs 167 days, respectively; p=.02). Hazard ratio for progression for DECT vital iodine TB non-responders versus responders was 6.9, versus 7.6 for EORTC PET, 3.3 for VTB, 2.3 for RECIST 1.1, and 2.1 for mChoi. C-index was 0.74 for EORTC PET, 0.73 for DECT vital iodine TB, 0.67 for VTB, 0.61 for RECIST 1.1, and 0.58 for mChoi. C-index was significantly greater for DECT vital iodine TB than RECIST 1.1 (p=.02) and mChoi (p=.002), but not different than VTB and EORTC PET (p>.05). DECT vital iodine TB criteria showed comparable performance as EORTC PET and outperformed RECIST 1.1 and mChoi for response assessment of metastatic GIST under TKI therapy. DECT vital iodine TB could help guide early management decisions in patients on TKI therapy.
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http://dx.doi.org/10.2214/AJR.21.26636DOI Listing
October 2021

Low risk of contrast media induced hypersensitivity reactions in all subtypes of systemic mastocytosis.

Ann Allergy Asthma Immunol 2021 Oct 9. Epub 2021 Oct 9.

Clinic of Clinical Radiology and Nuclear Medicine, University Hospital Mannheim, Heidelberg University, Mannheim, Germany. Electronic address:

Background: Patients with SM are at increased risk of hypersensitivity reactions. Although hymenoptera venoms are the predominant triggers, cases of CMIHR have also been reported and prophylactic premedication is often performed. However, data from larger series are limited and differences between indolent and advanced systemic mastocytosis have not yet been investigated.

Objective: To determine the incidence and severity of CMIHR in all subtypes of SM.

Methods: We analyzed 162 adult patients with SM (ISM, n=65; advSM, n=97). Firstly, the cumulative incidence of CMIHR was retrospectively assessed in the patient's history. Secondly, at our institution, patients underwent 332 CM-enhanced imagings including 80 CT scans with iodine-based contrast agent and 252 MRI with gadoliniumbased contrast agent and tolerance was assessed.

Results: Previous CMIHRs to CT (vomiting, n=1, erythema, n=1, cardiovascular shock, n=1) and MRI (dyspnea, n=1, cardiovascular shock, n=1) had been reported by 4/162 (2.5%) patients (ISM, n=3; advSM, n=1). In contrast, during or after 332 CM-enhanced CT/MRI examinations at our institution, no CMIHRs were reported. Premedication was solely given to 3 patients prior to CT scans, including one with previous CMIHR, who tolerated the imaging well.

Conclusion: We conclude that i) there is a significant discrepancy between perception and prevalence of hypersensitivity reactions to CM in SM, ii) reactions are scarce in ISM and even rarer in advSM, iii) in SM patients without previous history of CM hypersensitivity, prophylactic premedication prior to CM enhanced-CT/MRI is dispensable.
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http://dx.doi.org/10.1016/j.anai.2021.10.004DOI Listing
October 2021

Anthropometry of the proximal femur and femoral head in children/adolescents using three-dimensional computed tomography-based measurements.

Surg Radiol Anat 2021 Dec 1;43(12):2009-2023. Epub 2021 Oct 1.

Department of Orthopaedics and Traumatology Surgery, University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.

Purpose: Defining normal anthropometric ranges of proximal femur and femoral head for each age group in children/adolescents is a necessity when differentiating normal anatomical variants from pathological deformities. Aim of this study is to define a set of normal anthropometric parameters based on 3D-CT measurements in normal asymptomatic children/adolescents and analyse the variations arising depending on age, side, and/or gender.

Methods: Morphology of the proximal femur was retrospectively assessed in 170 hips (85 children, < 15 years). Measurements included covered femoral head volume (CFHV), femoral head diameter (FHD), femoral head extrusion index (FHEI), coronal alpha angle (CAA), lateral centre-edge angle (LCEA), anterior (AOS) and posterior head-neck offset (POS) and femoral neck-shaft angle (FNSA). Correlation analyses as well as inter- and intra-rater reliability were performed.

Results: CFHV, LCEA, FHD and AOS/POS increased with age and FHEI, CAA, and FNSA decreased with age. None of the measurements correlated with the side. AOS showed a poor correlation with gender. Rapid growth phases were observed at the age of 1, 7 and 11. The inter- and intra-rater reliability was high (range ICC 0.8-0.99 Cronbach alpha 0.86-0.99).

Conclusion: This data delivers a description of growth phases as well as gender and age-correlated reference values of the proximal femoral morphology that could be used by paediatricians and orthopaedic/paediatric surgeons to early diagnose proximal femur deformities and provide guidance in the planning of possible operations.
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http://dx.doi.org/10.1007/s00276-021-02841-3DOI Listing
December 2021

Detectability of Lung Nodules in Ultra-low Dose CT.

Anticancer Res 2021 Oct;41(10):5053-5058

Department of Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany

Background/aim: Investigation of the influence of different ultra-low dose computed tomography (ULDCT) protocols on the detection of solid and subsolid nodules in a phantom study.

Patients And Methods: A chest phantom with pulmonary nodules was scanned with different CT protocols ranging from ultra-low dose settings with spectral shaping to a standard low dose lung cancer screening protocol. Image analysis was performed with different reconstruction algorithms and dedicated computer aided detection (CAD), which was compared to manual readout.

Results: The highest sensitivity rates (83%) were achieved for the 90 mAs and 120 mAs protocols when reconstructed with ADMIRE 3 or 5 and manual readout. The only statistically significant difference was found for subsolid nodules with preference of manual readout compared to CAD (p<0.05). Dose levels for the mAs settings ranged from 0.029 to 0.2 mSv.

Conclusion: Reliable detectability rates for solid nodules were achieved; CAD software did not prove reliable for subsolid nodules.
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http://dx.doi.org/10.21873/anticanres.15320DOI Listing
October 2021

T2-weighted Imaging of the Breast at 1.5T Using Simultaneous Multi-slice Acceleration.

Anticancer Res 2021 Sep;41(9):4423-4429

Clinic of Radiology and Nuclear Medicine, University Medical Centre Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.

Aim: To evaluate the image quality and time saving using simultaneous multi-slice (SMS)-accelerated T2-weighted turbo spin echo (TSE) sequences compared to standard T2 TSE sequences in breast magnetic resonance imaging (MRI).

Patients And Methods: Thirty patients were examined with an SMS-accelerated T2 TSE sequence and a standard T2 TSE sequence as part of a breast MRI protocol at 1.5T. Image quality, signal homogeneity and tissue delineation were evaluated. For quantitative assessment, the signal-to-noise ratio (SNR) was measured from representative SNR maps.

Results: There were no significant differences regarding tissue delineation and signal homogeneity. Image quality was rated equal at the chest wall and the breasts but decreased in the axilla on SMS-T2 TSE (p=0.01) with a simultaneous decrease of SNR (p=0.03). This did not significantly impact the overall image quality (p=0.2). The acquisition time for SMS-T2 TSE was 48% shorter compared to standard T2 TSE.

Conclusion: SMS-acceleration for T2-weighted imaging of the breast at 1.5T substantially reduces acquisition time while maintaining comparable quantitative and qualitative image quality. This may pave the way for protocol abbreviation especially in a high-throughput clinical workspace.
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http://dx.doi.org/10.21873/anticanres.15249DOI Listing
September 2021

Robotic Assistance System for Cone-Beam Computed Tomography-Guided Percutaneous Needle Placement.

Cardiovasc Intervent Radiol 2021 Aug 19. Epub 2021 Aug 19.

University Medical Center Mannheim, Department of Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.

Purpose: The study aimed to evaluate a new robotic assistance system (RAS) for needle placement in combination with a multi-axis C-arm angiography system for cone-beam computed tomography (CBCT) in a phantom setting.

Materials And Methods: The RAS consisted of a tool holder, dedicated planning software, and a mobile platform with a lightweight robotic arm to enable image-guided needle placement in conjunction with CBCT imaging. A CBCT scan of the phantom was performed to calibrate the robotic arm in the scan volume and to plan the different needle trajectories. The trajectory data were sent to the robot, which then positioned the tool holder along the trajectory. A 19G needle was then manually inserted into the phantom. During the control CBCT scan, the exact needle position was evaluated and any possible deviation from the target lesion measured.

Results: In total, 16 needle insertions targeting eight in- and out-of-plane sites were performed. Mean angular deviation from planned trajectory to actual needle trajectory was 1.12°. Mean deviation from target point and actual needle tip position was 2.74 mm, and mean deviation depth from the target lesion to the actual needle tip position was 2.14 mm. Mean time for needle placement was 361 s. Only differences in time required for needle placement between in- and out-of-plane trajectories (337 s vs. 380 s) were statistically significant (p = 0.0214).

Conclusion: Using this RAS for image-guided percutaneous needle placement with CBCT was precise and efficient in the phantom setting.
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http://dx.doi.org/10.1007/s00270-021-02938-7DOI Listing
August 2021

[MRI-guided minimally invasive treatment of prostate cancer].

Radiologe 2021 Sep 12;61(9):829-838. Epub 2021 Jul 12.

Klinik für Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Deutschland.

Clinical/methodological Issue: Multiparametric magnetic resonance imaging (mpMRI) of the prostate plays a crucial role in the diagnosis and local staging of primary prostate cancer.

Standard Radiological Methods: Image-guided biopsy techniques such as MRI-ultrasound fusion not only allow guidance for targeted tissue sampling of index lesions for diagnostic confirmation, but also improve the detection of clinically significant prostate cancer.

Methodological Innovations: Minimally invasive, focal therapies of localized prostate cancer complement the treatment spectrum, especially for low- and intermediate-risk patients.

Performance: In patients of low and intermediate risk, MR-guided, minimally invasive therapies could enable local tumor control, improved functional outcomes and possible subsequent therapy escalation. Further study results related to multimodal approaches and the application of artificial intelligence (AI) by machine and deep learning algorithms will help to leverage the full potential of focal therapies for prostate cancer in the upcoming era of precision medicine.

Achievements: Completion of ongoing randomized trials comparing each minimally invasive therapy approach with established whole-gland procedures is needed before minimally invasive therapies can be implemented into existing treatment guidelines.

Practical Recommendations: This review article highlights minimally invasive therapies of prostate cancer and the key role of mpMRI for planning and conducting these therapies.
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http://dx.doi.org/10.1007/s00117-021-00883-7DOI Listing
September 2021

[The International Radiomics Platform - An Initiative of the German and Austrian Radiological Societies - First Application Examples].

Rofo 2021 Mar 22;193(3):e3. Epub 2021 Apr 22.

Department of Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany.

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http://dx.doi.org/10.1055/a-1475-0537DOI Listing
March 2021

Intraindividual Comparison of Compressed Sensing-Accelerated Cartesian and Radial Arterial Phase Imaging of the Liver in an Experimental Tumor Model.

Invest Radiol 2021 07;56(7):433-441

Department of Diagnostic and Interventional Radiology, University of Bonn, Bonn, Germany.

Objectives: The aim of this study was to intraindividually compare the performance of 2 compressed sensing (CS)-accelerated magnetic resonance imaging (MRI) sequences, 1 featuring Cartesian (compressed sensing volumetric interpolated breath-hold examination [CS-VIBE]) and the other radial (golden-angle radial sparse parallel [GRASP]) k-space sampling in continuous dynamic imaging during hepatic vascular phases, using extracellular and hepatocyte-specific contrast agents.

Materials And Methods: Seven New Zealand white rabbits, with induced VX2 liver tumors (median number of lesions, 2 ± 0.83; range, 1-3), received 2 continuously acquired T1-weighted prototype CS-accelerated MRI sequences (CS-VIBE and GRASP) with high spatial (0.8 × 0.8 × 1.5 mm) and temporal resolution (3.5 seconds) in randomized order on 2 separate days using a 1.5-T scanner. In all animals, imaging was performed using first gadobutrol at a dose of 0.1 mmol/kg and, then 45 minutes later, gadoxetic acid at a dose of 0.025 mmol/kg.The following qualitative parameters were assessed using 3- and 5-point Likert scales (3 and 5 being the highest scores respectively): image quality (IQ), arterial and venous vessel delineation, tumor enhancement, motion artifacts, and sequence-specific artifacts. Furthermore, the following quantitative parameters were obtained: relative peak signal enhancement, time to peak, mean transit time, and plasma flow ratios. Paired sampled t tests and Wilcoxon signed rank tests were used for intraindividual comparison. Image analysis was performed by 2 radiologists.

Results: Six of 7 animals underwent the full imaging protocol and obtained data were analyzed statistically. Overall IQ was rated moderate to excellent, not differing significantly between the 2 sequences.Gadobutrol-enhanced CS-VIBE examinations revealed the highest mean Likert scale values in terms of vessel delineation and tumor enhancement (arterial 4.4 [4-5], venous 4.3 [3-5], and tumor 2.9 [2-3]). Significantly, more sequence-specific artifacts were seen in GRASP examinations (P = 0.008-0.031). However, these artifacts did not impair IQ. Excellent Likert scale ratings were found for motion artifacts in both sequences. In both sequences, a maximum of 4 hepatic arterial dominant phases were obtained. Regarding the relative peak signal enhancement, CS-VIBE and GRASP showed similar results. The relative peak signal enhancement values did not differ significantly between the 2 sequences in the aorta, the hepatic artery, or the inferior vena cava (P = 0.063-0.536). However, significantly higher values were noted for CS-VIBE in gadoxetic acid-enhanced examinations in the portal vein (P = 0.031) and regarding the tumor enhancement (P = 0.005). Time to peak and mean transit time or plasma flow ratios did not differ significantly between the sequences.

Conclusions: Both CS-VIBE and GRASP provide excellent results in dynamic liver MRI using extracellular and hepatocyte-specific contrast agents, in terms of IQ, peak signal intensity, and presence of artifacts.
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http://dx.doi.org/10.1097/RLI.0000000000000767DOI Listing
July 2021

Impact of Chronic Prostatitis on the PI-RADS Score 3: Proposal for the Addition of a Novel Binary Suffix.

Diagnostics (Basel) 2021 Mar 30;11(4). Epub 2021 Mar 30.

Department of Urology, Kantonsspital Baden, 5404 Baden, Switzerland.

We examined the impact of chronic prostatitis on the diagnostic performance of multiparametric magnetic resonance imaging (mpMRI). In this retrospective study, 63 men underwent 3T mpMRI followed by MRI/ultrasound fusion biopsy to exclude/confirm clinically significant prostate cancer (csPCa). A total of 93 lesions were included for evaluation. Images were assessed by two radiologists. Prostatitis was graded visually on T2-weighted and contrast-enhanced sequences. The correlation of prostatitis features with the assigned Prostate Imaging Reporting and Data System (PI-RADS) and the presence of csPCa were assessed, and the clinical and functional imaging parameters for differentiating between prostatitis and significant tumors were examined. Histopathological analysis was used as the reference standard. The rate of PI-RADS 3 scores tended to be higher in the presence of radiologically severe prostatitis compared with no/discrete prostatitis ( = 52 vs. = 9; = 0.225). In severe prostatitis, csPCa was determined in only 7.7% (4/52) of PI-RADS 3 lesions. In severe chronic prostatitis, a binary prostatitis suffix (e.g., PI-RADS 3 i+ versus i-) within the radiological report may help assess the limitations of mpMRI interpretability because of severe prostatitis and avoid unnecessary biopsies. Mean apparent diffusion coefficient (ADC) was the best marker (cutoff 0.93 × 10 mm/s) to differentiate between csPCa/non csPCa in severe prostatitis.
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http://dx.doi.org/10.3390/diagnostics11040623DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066731PMC
March 2021

F FDG PET/MRI with hepatocyte-specific contrast agent for M staging of rectal cancer: a primary economic evaluation.

Eur J Nucl Med Mol Imaging 2021 09 9;48(10):3268-3276. Epub 2021 Mar 9.

Department of Radiology and Nuclear Medicine, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.

Purpose: Rectal cancer is one of the most frequent causes of cancer-related morbidity and mortality in the world. Correct identification of the TNM state in primary staging of rectal cancer has critical implications on patient management. Initial evaluations revealed a high sensitivity and specificity for whole-body PET/MRI in the detection of metastases allowing for metastasis-directed therapy regimens. Nevertheless, its cost-effectiveness compared with that of standard-of-care imaging (SCI) using pelvic MRI + chest and abdominopelvic CT is yet to be investigated. Therefore, the aim of this study was to analyze the cost-effectiveness of whole-body F FDG PET/MRI as an alternative imaging method to standard diagnostic workup for initial staging of rectal cancer.

Methods: For estimation of quality-adjusted life years (QALYs) and lifetime costs of diagnostic modalities, a decision model including whole-body F FDG PET/MRI with a hepatocyte-specific contrast agent and pelvic MRI + chest and abdominopelvic CT was created based on Markov simulations. For obtaining model input parameters, review of recent literature was performed. Willingness to pay (WTP) was set to $100,000/QALY. Deterministic sensitivity analysis of diagnostic parameters and costs was applied, and probabilistic sensitivity was determined using Monte Carlo modeling.

Results: In the base-case scenario, the strategy whole-body F FDG PET/MRI resulted in total costs of $52,186 whereas total costs of SCI were at $51,672. Whole-body F FDG PET/MRI resulted in an expected effectiveness of 3.542 QALYs versus 3.535 QALYs for SCI. This resulted in an incremental cost-effectiveness ratio of $70,291 per QALY for PET/MRI. Thus, from an economic point of view, whole-body F FDG PET/MRI was identified as an adequate diagnostic alternative to SCI with high robustness of results to variation of input parameters.

Conclusion: Based on the results of the analysis, use of whole-body F FDG PET/MRI was identified as a feasible diagnostic strategy for initial staging of rectal cancer from a cost-effectiveness perspective.
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http://dx.doi.org/10.1007/s00259-021-05193-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8426298PMC
September 2021

Incomplete neo-endothelialization of left atrial appendage closure devices is frequent after 6 months: a pilot imaging study.

Int J Cardiovasc Imaging 2021 Jul 5;37(7):2291-2298. Epub 2021 Mar 5.

First Department of Medicine, University Medical Center Mannheim (UMM), Faculty of Medicine Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.

Purpose: To bridge neo-endothelialization (NE) of implanted left atrial appendage closure (LAA/LAAC) devices, dual antiplatelet therapy is prescribed. Cardiac computed tomography angiography (cCTA) has been proposed for the evaluation of interventional LAAC. This prospective longitudinal observational study applied a standardized imaging protocol to detect progression of NE of LAAC devices 6 months after implantation.

Methods: Consecutive cCTA datasets of patients six months after LAAC were acquired and the standardized multi-planar reconstruction LAA occluder view for post-implantation evaluation (LOVE) algorithm was used. Residual flow of contrast agent inside the LAA without a peri-device leak (PDL) was defined as incomplete neo-endothelialization. Absence of residual flow was defined as complete neo-endothelialization. Since PDL allows residual flow in the LAA, irrespective of neoendothelialization, PDL were excluded from this study. Diabetes mellitus, liver disease, body-mass-index, age, device sizes and type will be assessed as predictors for incomplete NE.

Results: 53 consecutive patients were recruited for cCTA imaging. 36 (68%) showed no PDL and were included in the study (median age 77 years, 19% female). At median follow-up of 6 months (median 180 days, IQR 178-180), 44% of patients showed complete NE compared to 56% with NE still incomplete. Age, BMI, device type and size as well as prevalence of diabetes mellitus and liver disease did not show significant correlation with the completeness of NE.

Conclusion: This pilot study showed that neo-endothelialization is still incomplete in a majority of patients at mid-term follow-up of 6 months after successful LAAC therapy. Further investigation on the consequences of incomplete endothelialization is needed to guide antiplatelet therapy schedules.
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http://dx.doi.org/10.1007/s10554-021-02192-5DOI Listing
July 2021

Computed tomography based measurements to evaluate lung density and lung growth after congenital diaphragmatic hernia.

Sci Rep 2021 Mar 3;11(1):5035. Epub 2021 Mar 3.

Department of Radiology and Nuclear Medicine, Medical Faculty Mannheim, University Medical Center Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.

Emphysema-like-change of lung is one aspect of lung morbidity in children after congenital diaphragmatic hernia (CDH). This study aims to evaluate if the extent of reduced lung density can be quantified through pediatric chest CT examinations, if side differences are present and if emphysema-like tissue is more prominent after CDH than in controls. Thirty-seven chest CT scans of CDH patients (mean age 4.5 ± 4.0 years) were analyzed semi-automatically and compared to an age-matched control group. Emphysema-like-change was defined as areas of lung density lower than - 950 HU in percentage (low attenuating volume, LAV). A p-value lower than 0.05 was regarded as statistically significant. Hypoattenuating lung tissue was more frequently present in the ipsilateral lung than the contralateral side (LAV 12.6% vs. 5.7%; p < 0.0001). While neither ipsilateral nor contralateral lung volume differed between CDH and control (p > 0.05), LAV in ipsilateral (p = 0.0002), but not in contralateral lung (p = 0.54), was higher in CDH than control. It is feasible to quantify emphysema-like-change in pediatric patients after CDH. In the ipsilateral lung, low-density areas are much more frequently present both in comparison to contralateral and to controls. Especially the ratio of LAV ipsilateral/contralateral seems promising as a quantitative parameter in the follow-up after CDH.
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http://dx.doi.org/10.1038/s41598-021-84623-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930262PMC
March 2021

[Diagnostic value of a 3D-SPACE-sequence with compressed sensing technology for the knee joint].

Radiologe 2021 Feb 21;61(2):203-212. Epub 2020 Dec 21.

Radiologisches Zentrum für Diagnostik und Therapie München, Oberföhringer Straße 2, 81679, München, Deutschland.

Backround: SPACE (3D fast spin echo acquisition) sequences require long scan times for three-dimensional assessment of acute injury of the knee joint and are flawed due to geometric blurring. Their implementation into routine diagnostic imaging was not feasible until recently.

Objectives: By comparing conventional MRI (magnetic resonance imaging) sequences to 3D (three-dimensional) sequences, it was investigated whether the compressed sensing (CS) technique is inferior to the established 2D sequences with shorter examination times.

Materials And Methods: A total of 109 patients (age range 18-50 years) with knee injury were examined by MRI between April 2017 and May 2018. The inter- and intraobserver concordance of two blinded readers were assessed. Consensus was achieved in case of discrepancies. Descriptive analyses of absolute and relative frequency and distribution were tested by Fisher's exact test concerning differences between CS-SPACE and standard proton density fat suppressed imaging.

Results: Interoberserver concordance (IC) of conventional sequences before/after consensus amounted to 58.8/68.1% (medial meniscus, MM), 68.8/88.7% (lateral meniscus, LM) 88.9/97.2% (anterior cruciate ligament, ACL), 99/100% (posterior cruciate ligament, PCL), 88.9/97.2% (collateral ligament, CL) and chondral injury (CI) 1-2: 64.2%, CI-3: 77% and CI-4: 76%. The IC of CS-SPACE amounted before/after consensus of MM to 50.4/77%, LM 68.8/88%, ACL 89.9/94.5%, PCL 97.2/99.0%, CL 92.6/96.3%. IC of CI was evaluated without consensus and amounted to 65.1% (CI 1-2), 66% (CI 3) and 81.6% (CI 4).

Conclusions: Injuries of ACL, PCL and CL have excellent IC between 3D and 2D sequences. Excellent IC could be found in CI grade 3 and 4 when using 2D sequences and CI grade 4 utilizing CS-SPACE. Our results indicate that CS-SPACE is useful in diagnosing acute knee injuries.
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http://dx.doi.org/10.1007/s00117-020-00788-xDOI Listing
February 2021

The International Radiomics Platform - An Initiative of the German and Austrian Radiological Societies - First Application Examples.

Rofo 2021 Mar 26;193(3):276-288. Epub 2020 Nov 26.

Department of Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany.

Purpose:  The DRG-ÖRG IRP (Deutsche Röntgengesellschaft-Österreichische Röntgengesellschaft international radiomics platform) represents a web-/cloud-based radiomics platform based on a public-private partnership. It offers the possibility of data sharing, annotation, validation and certification in the field of artificial intelligence, radiomics analysis, and integrated diagnostics. In a first proof-of-concept study, automated myocardial segmentation and automated myocardial late gadolinum enhancement (LGE) detection using radiomic image features will be evaluated for myocarditis data sets.

Materials And Methods:  The DRG-ÖRP IRP can be used to create quality-assured, structured image data in combination with clinical data and subsequent integrated data analysis and is characterized by the following performance criteria: Possibility of using multicentric networked data, automatically calculated quality parameters, processing of annotation tasks, contour recognition using conventional and artificial intelligence methods and the possibility of targeted integration of algorithms. In a first study, a neural network pre-trained using cardiac CINE data sets was evaluated for segmentation of PSIR data sets. In a second step, radiomic features were applied for segmental detection of LGE of the same data sets, which were provided multicenter via the IRP.

Results:  First results show the advantages (data transparency, reliability, broad involvement of all members, continuous evolution as well as validation and certification) of this platform-based approach. In the proof-of-concept study, the neural network demonstrated a Dice coefficient of 0.813 compared to the expert's segmentation of the myocardium. In the segment-based myocardial LGE detection, the AUC was 0.73 and 0.79 after exclusion of segments with uncertain annotation.The evaluation and provision of the data takes place at the IRP, taking into account the FAT (fairness, accountability, transparency) and FAIR (findable, accessible, interoperable, reusable) criteria.

Conclusion:  It could be shown that the DRG-ÖRP IRP can be used as a crystallization point for the generation of further individual and joint projects. The execution of quantitative analyses with artificial intelligence methods is greatly facilitated by the platform approach of the DRG-ÖRP IRP, since pre-trained neural networks can be integrated and scientific groups can be networked.In a first proof-of-concept study on automated segmentation of the myocardium and automated myocardial LGE detection, these advantages were successfully applied.Our study shows that with the DRG-ÖRP IRP, strategic goals can be implemented in an interdisciplinary way, that concrete proof-of-concept examples can be demonstrated, and that a large number of individual and joint projects can be realized in a participatory way involving all groups.

Key Points:   · The DRG-ÖRG IRP is a web/cloud-based radiomics platform based on a public-private partnership.. · The DRG-ÖRG IRP can be used for the creation of quality-assured, structured image data in combination with clinical data and subsequent integrated data analysis.. · First results show the applicability of left ventricular myocardial segmentation using a neural network and segment-based LGE detection using radiomic image features.. · The DRG-ÖRG IRP offers the possibility of integrating pre-trained neural networks and networking of scientific groups..

Citation Format: · Overhoff D, Kohlmann P, Frydrychowicz A et al. The International Radiomics Platform - An Initiative of the German and Austrian Radiological Societies. Fortschr Röntgenstr 2021; 193: 276 - 287.
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http://dx.doi.org/10.1055/a-1244-2775DOI Listing
March 2021

Joint Imaging Platform for Federated Clinical Data Analytics.

JCO Clin Cancer Inform 2020 11;4:1027-1038

German Cancer Consortium, Heidelberg, Germany.

Purpose: Image analysis is one of the most promising applications of artificial intelligence (AI) in health care, potentially improving prediction, diagnosis, and treatment of diseases. Although scientific advances in this area critically depend on the accessibility of large-volume and high-quality data, sharing data between institutions faces various ethical and legal constraints as well as organizational and technical obstacles.

Methods: The Joint Imaging Platform (JIP) of the German Cancer Consortium (DKTK) addresses these issues by providing federated data analysis technology in a secure and compliant way. Using the JIP, medical image data remain in the originator institutions, but analysis and AI algorithms are shared and jointly used. Common standards and interfaces to local systems ensure permanent data sovereignty of participating institutions.

Results: The JIP is established in the radiology and nuclear medicine departments of 10 university hospitals in Germany (DKTK partner sites). In multiple complementary use cases, we show that the platform fulfills all relevant requirements to serve as a foundation for multicenter medical imaging trials and research on large cohorts, including the harmonization and integration of data, interactive analysis, automatic analysis, federated machine learning, and extensibility and maintenance processes, which are elementary for the sustainability of such a platform.

Conclusion: The results demonstrate the feasibility of using the JIP as a federated data analytics platform in heterogeneous clinical information technology and software landscapes, solving an important bottleneck for the application of AI to large-scale clinical imaging data.
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http://dx.doi.org/10.1200/CCI.20.00045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7713526PMC
November 2020

Contrast Saline Mixture DualFlow Injection Protocols for Low-Kilovolt Computed Tomography Angiography: A Systematic Phantom and Animal Study.

Invest Radiol 2020 12;55(12):785-791

Department of Diagnostic and Interventional Radiology, University Hospital Bonn, Rheinische-Friedrich-Wilhelms-Universität Bonn, North Rhine-Westphalia (NRW), Germany.

Objective: The aim of this study was to evaluate a contrast media (CM)-saline mixture administration with DualFlow (DF) to adapt injection protocols to low-kilovolt (kV) computed tomography angiography (CTA).

Materials And Methods: In both a circulation phantom and animal model (5 Goettingen minipigs), 3 injection protocols were compared in dynamic thoracic CTA: (a) DF injection protocol at 80 kV with a iodine delivery rate (IDR) of 0.9 gI/s, a flowrate of 5 mL/s injected with a 60%/40% ratio of iopromide (300 mgI/mL) and saline (dose contrast medium 180 mgI/kg body weight [BW]); (b) reference CTA was performed at 120 kV and a 40% higher iodine dose applied at higher IDR (1.5 gI/s, 5 mL/s iopromide [300 mgI/mL]; no simultaneously administered saline; 300 mgI/kg BW); and (c) conventional single-flow (SF) protocol with identical IDR as the DF protocol at 80 kV (0.9 gI/s, 3 mL/s iopromide [300 mgI/mL]; no simultaneously administered saline; 180 mgI/kg BW). All 3 injection protocols are followed by a saline chaser applied at the same flow rate as the corresponding CM injection. Time attenuation curves representing the vascular bolus shape were generated for pulmonary trunk and descending aorta.

Results: In the circulation phantom, pulmonary and aortic time attenuation curves for the 80 kV DF injection protocols do not significantly differ from the 80 kV SF and the 120 kV SF reference. In the animal model, the 80 kV DF protocol shows similar pulmonal and aortic peak enhancement when compared with the 120 kV SF and 80 kV SF protocols. Also, the bolus length above an attenuation level of 300 HU reveals no significant differences between injection protocols. However, the time to peak was significantly shorter for the 80 kV DF when compared with the 80 kV SF protocol (15.78 ± 1.9 seconds vs 18.24 ± 2.0 seconds; P = 0.008).

Conclusion: DualFlow injection protocols can be tailored for low-kV CTA by reducing the IDR while overall flow rate remains unchanged. Although no differences in attenuation were found, DF injections offer a shorter time to peak closer to the reference 120 kV protocol.This allows the use of DF injection protocols to calibrate bolus density in low-kV CTA and yields the potential for a more individualized CM administration.
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http://dx.doi.org/10.1097/RLI.0000000000000706DOI Listing
December 2020

Augmented reality with HoloLens in parotid surgery: how to assess and to improve accuracy.

Eur Arch Otorhinolaryngol 2021 Jul 10;278(7):2473-2483. Epub 2020 Sep 10.

Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.

Purpose: Augmented reality improves planning and execution of surgical procedures. The aim of this study was to evaluate the feasibility of a 3D augmented reality hologram in live parotic surgery. Another goal was to develop an accuracy measuring instrument and to determine the accuracy of the system.

Methods: We created a software to build and manually align 2D and 3D augmented reality models generated from MRI data onto the patient during surgery using the HoloLens 1 (Microsoft Corporation, Redmond, USA). To assess the accuracy of the system, we developed a specific measuring tool applying a standard electromagnetic navigation device (Fiagon GmbH, Hennigsdorf, Germany).

Results: The accuracy of our system was measured during real surgical procedures. Training of the experimenters and the use of fiducial markers significantly reduced the accuracy of holographic system (p = 0.0166 and p = 0.0132). Precision of the developed measuring system was very high with a mean error of the basic system of 1.3 mm. Feedback evaluation demonstrated 86% of participants agreed or strongly agreed that the HoloLens will play a role in surgical education. Furthermore, 80% of participants agreed or strongly agreed that the HoloLens is feasible to be introduced in clinical routine and will play a role within surgery in the future.

Conclusion: The use of fiducial markers and repeated training reduces the positional error between the hologram and the real structures. The developed measuring device under the use of the Fiagon navigation system is suitable to measure accuracies of holographic augmented reality images of the HoloLens.
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http://dx.doi.org/10.1007/s00405-020-06351-7DOI Listing
July 2021

Continuous Learning AI in Radiology: Implementation Principles and Early Applications.

Radiology 2020 Oct 25;297(1):6-14. Epub 2020 Aug 25.

From the Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, FND-210, Boston, MA 02114-2698 (O.S.P., J.A.B.); International Society for Strategic Studies in Radiology (IS3R), Vienna, Austria (M.D., D.R.E., C.J.H., S.O.S., J.A.B.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (G.L., C.J.H.); Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, Boston, Mass (G.L.); Department of Radiology, Charité-Universitätsmedizin, Berlin, Germany (M.D.); Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, Calif (D.R.E.); and Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany (S.O.S.).

Artificial intelligence (AI) is becoming increasingly present in radiology and health care. This expansion is driven by the principal AI strengths: automation, accuracy, and objectivity. However, as radiology AI matures to become fully integrated into the daily radiology routine, it needs to go beyond replicating static models, toward discovering new knowledge from the data and environments around it. Continuous learning AI presents the next substantial step in this direction and brings a new set of opportunities and challenges. Herein, the authors discuss the main concepts and requirements for implementing continuous AI in radiology and illustrate them with examples from emerging applications.
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http://dx.doi.org/10.1148/radiol.2020200038DOI Listing
October 2020

Response of advanced HCC to pembrolizumab and lenvatinib combination therapy despite monotherapy failure.

Z Gastroenterol 2020 Aug 12;58(8):773-777. Epub 2020 Aug 12.

Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.

In recent years, immune checkpoint inhibitors (ICIs) were successfully introduced to cancer therapy, and these drugs have already become essential for the treatment of various noncurable tumors. However, monotherapy in advanced hepatocellular carcinoma (aHCC) failed to show statistically significant improvement.Recently, the combination of atezolizumab and bevacizumab demonstrated efficacy of combining ICI and VEGF inhibition, further substantiating previous data on synergistic mechanisms among respective substance classes.As TKI treatment is currently standard of care for aHCC, and ICIs are approved by the FDA and available in many areas of the world, numerous patients may have been treated with monotherapy of those drugs. However, it remains unclear if failure to monotherapy has an impact on combination therapy. We therefore report a patient well responding to combination therapy despite previous failures to TKI and ICI monotherapy.
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http://dx.doi.org/10.1055/a-1190-5681DOI Listing
August 2020

Multiparametric MRI for Prostate Cancer Characterization: Combined Use of Radiomics Model with PI-RADS and Clinical Parameters.

Cancers (Basel) 2020 Jul 2;12(7). Epub 2020 Jul 2.

Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, D-68167 Mannheim, Germany.

Radiomics is an emerging field of image analysis with potential applications in patient risk stratification. This study developed and evaluated machine learning models using quantitative radiomic features extracted from multiparametric magnetic resonance imaging (mpMRI) to detect and classify prostate cancer (PCa). In total, 191 patients that underwent prostatic mpMRI and combined targeted and systematic fusion biopsy were retrospectively included. Segmentations of the whole prostate glands and index lesions were performed manually in apparent diffusion coefficient (ADC) maps and T2-weighted MRI. Radiomic features were extracted from regions corresponding to the whole prostate gland and index lesion. The best performing combination of feature setup and classifier was selected to compare its predictive ability of the radiologist's evaluation (PI-RADS), mean ADC, prostate specific antigen density (PSAD) and digital rectal examination (DRE) using receiver operating characteristic (ROC) analysis. Models were evaluated using repeated 5-fold cross-validation and a separate independent test cohort. In the test cohort, an ensemble model combining a radiomics model, with models for PI-RADS, PSAD and DRE achieved high predictive AUCs for the differentiation of (i) malignant from benign prostatic lesions (AUC = 0.889) and of (ii) clinically significant (csPCa) from clinically insignificant PCa (cisPCa) (AUC = 0.844). Our combined model was numerically superior to PI-RADS for cancer detection (AUC = 0.779; = 0.054) as well as for clinical significance prediction (AUC = 0.688; = 0.209) and showed a significantly better performance compared to mADC for csPCa prediction (AUC = 0.571; = 0.022). In our study, radiomics accurately characterizes prostatic index lesions and shows performance comparable to radiologists for PCa characterization. Quantitative image data represent a potential biomarker, which, when combined with PI-RADS, PSAD and DRE, predicts csPCa more accurately than mADC. Prognostic machine learning models could assist in csPCa detection and patient selection for MRI-guided biopsy.
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http://dx.doi.org/10.3390/cancers12071767DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407326PMC
July 2020

More holes, more contrast? Comparing an 18-gauge non-fenestrated catheter with a 22-gauge fenestrated catheter for cardiac CT.

PLoS One 2020 8;15(6):e0234311. Epub 2020 Jun 8.

Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Homburg, Germany.

Objective: To compare the performance of an 18-gauge nonfenestrated catheter (18-NFC) with a 22-gauge fenestrated catheter (22-FC) for cardiac CT angiography (CCTA) in patients with suspected coronary heart disease.

Subjects And Methods: 74 consecutive patients imaged on a 2nd generation dual-source CT with arterial phase CCTA were included in this retrospective investigation to either an 18-NFC or 22-FC. In comparison to the 18-NFC, the 22-FC has three additional perforations for contrast agent dispersal proximal to the tip. We examined the two groups for differences in their average attenuation in the right and left ventricles (RV, LV) and in the atrium (RA, LA) as well as in the proximal right coronary artery (RCA) and the left main coronary artery (LM). The averages were calculated for both the 18-NFC and 22-FC.

Results: Catheters were successfully placed on the first attempt 97% (36/37) for 18-NFC and 95% (35/37) for the 22-FC. The following enhancement levels were measured: 22-FC (in Hounsfield-Units (HU)): RV = 203±29, LV = 523±36, RA = 198±29, LA = 519±38, RCA = 547±26, LM = 562±25; 18-NFC: RV = 146±26, LV = 464±32, RA = 141±24, LA = 438±35, RCA = 501±23, LM = 523±23; RV (p = 0,03), LV (p = 0.12), RA (p = 0.02), LA (p = 0.04), RCA (p = 0.3), LM (p = 0.33).

Conclusion: No significant differences in attenuation levels as well as in image quality of the coronary arteries were found between NFC and FC. Nevertheless, the 22-gauge FC examinations showed significantly higher attenuation in the left and right atrium as well as the right ventricle. Patients with poor venous access may benefit from a smaller gauge catheter that can deliver sufficiently high flow rates for CCTA.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0234311PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7279574PMC
August 2020

Acute pulmonary embolism mimicking COVID - 19 pneumonia.

Int J Infect Dis 2020 07 18;96:475-476. Epub 2020 May 18.

Department of Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Baden-Württemberg, D-68167, Germany.

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http://dx.doi.org/10.1016/j.ijid.2020.05.053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7233210PMC
July 2020

MITIGATE-NeoBOMB1, a Phase I/IIa Study to Evaluate Safety, Pharmacokinetics, and Preliminary Imaging of Ga-NeoBOMB1, a Gastrin-Releasing Peptide Receptor Antagonist, in GIST Patients.

J Nucl Med 2020 12 24;61(12):1749-1755. Epub 2020 Apr 24.

Department of Nuclear Medicine, Medical University Innsbruck, Innsbruck, Austria

Gastrin-releasing peptide receptors (GRPRs) are potential molecular imaging targets in a variety of tumors. Recently, a Ga-labeled antagonist to GRPRs, NeoBOMB1, was developed for PET. We report on the outcome of a phase I/IIa clinical trial (EudraCT 2016-002053-38) within the EU-FP7 project Closed-loop Molecular Environment for Minimally Invasive Treatment of Patients with Metastatic Gastrointestinal Stromal Tumors ('MITIGATE') (grant agreement no. 602306) in patients with oligometastatic gastrointestinal stromal tumors (GIST). The main objectives were evaluation of safety, biodistribution, dosimetry, and preliminary tumor targeting of Ga-NeoBOMB1 in patients with advanced tyrosine-kinase inhibitors-treated GIST using PET/CT. Six patients with histologically confirmed GIST and unresectable primary lesion or metastases undergoing an extended protocol for detailed pharmacokinetic analysis were included. Ga-NeoBOMB1 was prepared using a kit procedure with a licensed Ge/Ga generator. Ga-NeoBOMB1 (3 MBq/kg of body weight) was injected intravenously, and safety parameters were assessed. PET/CT included dynamic imaging at 5, 11, and 19 min as well as static imaging at 1, 2, and 3-4 h after injection for dosimetry calculations. Venous blood samples and urine were collected for pharmacokinetic analysis. Tumor targeting was assessed on a per-lesion and per-patient basis. Ga-NeoBOMB1 (50 μg) was prepared with high radiochemical purity (yield > 97%). Patients received 174 ± 28 MBq of the radiotracer, which was well tolerated in all patients over a follow-up period of 4 wk. Dosimetry calculations revealed a mean effective dose of 0.029 ± 0.06 mSv/MBq, with the highest organ dose to the pancreas (0.274 ± 0.099 mSv/MBq). Mean plasma half-life was 27.3 min with primarily renal clearance (mean 25.7% ± 5.4% of injected dose 4 h after injection). Plasma metabolite analyses revealed high stability; metabolites were detected only in the urine. In 3 patients, a significant uptake with increasing maximum SUVs (SUV at 2 h after injection: 4.3-25.9) over time was found in tumor lesions. This phase I/IIa study provides safety data for Ga-NeoBOMB1, a promising radiopharmaceutical for targeting GRPR-expressing tumors. Safety profiles and pharmacokinetics are suitable for PET imaging, and absorbed dose estimates are comparable to those of other Ga-labeled radiopharmaceuticals used in clinical routine.
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http://dx.doi.org/10.2967/jnumed.119.238808DOI Listing
December 2020

Prognostic Value of Coronary Computed Tomography Angiography-derived Morphologic and Quantitative Plaque Markers Using Semiautomated Plaque Software.

J Thorac Imaging 2021 Mar;36(2):108-115

Institute of Clinical Radiology and Nuclear Medicine, Faculty of Medicine Mannheim.

Purpose: In this study, we analyzed the prognostic value of coronary computed tomography angiography-derived morphologic and quantitative plaque markers and plaque scores for major adverse cardiovascular events (MACEs).

Materials And Methods: We analyzed the data of patients with suspected coronary artery disease (CAD). Various plaque markers were obtained using a semiautomated software prototype or derived from the results of the software analysis. Several risk scores were calculated, and follow-up data concerning MACE were collected from all patients.

Results: A total of 131 patients (65±12 y, 73% male) were included in our study. MACE occurred in 11 patients within the follow-up period of 34±25 months.CAD-Reporting and Data System score (odds ratio [OR]=11.62), SYNTAX score (SS) (OR=1.11), Leiden-risk score (OR=1.37), segment involvement score (OR=1.76), total plaque volume (OR=1.20), and percentage aggregated plaque volume (OR=1.32) were significant predictors for MACE (all P≤0.05). Moreover, the difference of the corrected coronary opacification (ΔCCO) correlated significantly with the occurrence of MACE (P<0.0001). The CAD-Reporting and Data System score, SS, and Leiden-risk score showed substantial sensitivity for predicting MACE (90.9%). The SS and Leiden-risk score displayed high specificities of 80.8% and 77.5%, respectively. These plaque markers and risk scores all provided high negative predictive value (>90%).

Conclusion: The coronary computed tomography angiography-derived plaque markers of segment involvement score, total plaque volume, percentage aggregated plaque volume, and ΔCCO, and the risk scores exhibited predictive value for the occurrence of MACE and can likely aid in identifying patients at risk for future cardiac events.
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http://dx.doi.org/10.1097/RTI.0000000000000509DOI Listing
March 2021

Artificial Intelligence-based Fully Automated Per Lobe Segmentation and Emphysema-quantification Based on Chest Computed Tomography Compared With Global Initiative for Chronic Obstructive Lung Disease Severity of Smokers.

J Thorac Imaging 2020 May;35 Suppl 1:S28-S34

Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, Charleston, SC.

Objectives: The objective of this study was to evaluate an artificial intelligence (AI)-based prototype algorithm for the fully automated per lobe segmentation and emphysema quantification (EQ) on chest-computed tomography as it compares to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) severity classification of chronic obstructive pulmonary disease (COPD) patients.

Methods: Patients (n=137) who underwent chest-computed tomography acquisition and spirometry within 6 months were retrospectively included in this Institutional Review Board-approved and Health Insurance Portability and Accountability Act-compliant study. Patient-specific spirometry data, which included forced expiratory volume in 1 second, forced vital capacity, and the forced expiratory volume in 1 second/forced vital capacity ratio (Tiffeneau-Index), were used to assign patients to their respective GOLD stage I to IV. Lung lobe segmentation was carried out using AI-RAD Companion software prototype (Siemens Healthineers), a deep convolution image-to-image network and emphysema was quantified in each lung lobe to detect the low attenuation volume.

Results: A strong correlation between the whole-lung-EQ and the GOLD stages was found (ρ=0.88, P<0.0001). The most significant correlation was noted in the left upper lobe (ρ=0.85, P<0.0001), and the weakest in the left lower lobe (ρ=0.72, P<0.0001) and right middle lobe (ρ=0.72, P<0.0001).

Conclusions: AI-based per lobe segmentation and its EQ demonstrate a very strong correlation with the GOLD severity stages of COPD patients. Furthermore, the low attenuation volume of the left upper lobe not only showed the strongest correlation to GOLD severity but was also able to most clearly distinguish mild and moderate forms of COPD. This is particularly relevant due to the fact that early disease processes often elude conventional pulmonary function diagnostics. Earlier detection of COPD is a crucial element for positively altering the course of disease progression through various therapeutic options.
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http://dx.doi.org/10.1097/RTI.0000000000000500DOI Listing
May 2020

Comparison of Machine Learning Computed Tomography-Based Fractional Flow Reserve and Coronary CT Angiography-Derived Plaque Characteristics with Invasive Resting Full-Cycle Ratio.

J Clin Med 2020 Mar 6;9(3). Epub 2020 Mar 6.

First Department of Medicine-Cardiology, University Medical Centre Mannheim, and DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Mannheim 68167, Germany.

Background: The aim is to compare the machine learning-based coronary-computed tomography fractional flow reserve (CT-FFR) and coronary-computed tomographic morphological plaque characteristics with the resting full-cycle ratio (RFR) as a novel invasive resting pressure-wire index for detecting hemodynamically significant coronary artery stenosis.

Methods: In our single center study, patients with coronary artery disease (CAD) who had a clinically indicated coronary computed tomography angiography (cCTA) and subsequent invasive coronary angiography (ICA) with pressure wire-measurement were included. On-site prototype CT-FFR software and on-site CT-plaque software were used to calculate the hemodynamic relevance of coronary stenosis.

Results: We enrolled 33 patients (70% male, mean age 68 ± 12 years). On a per-lesion basis, the area under the receiver operating characteristic curve (AUC) of CT-FFR (0.90) was higher than the AUCs of the morphological plaque characteristics length/minimal luminal diameter (LL/MLD; 0.80), minimal luminal diameter (MLD; 0.77), remodeling index (RI; 0.76), degree of luminal diameter stenosis (0.75), and minimal luminal area (MLA; 0.75).

Conclusion: CT-FFR and morphological plaque characteristics show a significant correlation to detected hemodynamically significant coronary stenosis. Whole CT-FFR had the best discriminatory power, using RFR as the reference standard.
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http://dx.doi.org/10.3390/jcm9030714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7141220PMC
March 2020

Contralateral Liver Hypertrophy and Oncological Outcome Following Radioembolization with Y-Microspheres: A Systematic Review.

Cancers (Basel) 2020 Jan 27;12(2). Epub 2020 Jan 27.

Department of Surgery, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany.

Radioembolization with Y-microspheres has been reported to induce contralateral liver hypertrophy with simultaneous ipsilateral control of tumor growth. The aim of the present systematic review was to summarize the evidence of contralateral liver hypertrophy and oncological outcome following unilateral treatment with radioembolization. A systematic literature search using the MEDLINE, EMBASE, and Cochrane libraries for studies published between 2008 and 2020 was performed. A total of 16 studies, comprising 602 patients, were included. The median kinetic growth rate per week of the contralateral liver lobe was 0.7% and declined slightly over time. The local tumor control was 84%. Surgical resection after radioembolization was carried out in 109 out of 362 patients (30%). Although the available data suggest that radioembolization prior to major hepatectomy is safe with a promising oncological outcome, the definitive role of radioembolization requires assessment within controlled clinical trials.
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http://dx.doi.org/10.3390/cancers12020294DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072354PMC
January 2020

An increased bone mineral density is an adverse prognostic factor in patients with systemic mastocytosis.

J Cancer Res Clin Oncol 2020 Apr 24;146(4):945-951. Epub 2020 Jan 24.

Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany.

Purpose: Systemic mastocytosis (SM) is characterized by the expansion of clonal mast cells that infiltrate various organ systems. The extent of organ infiltration and subsequent organ damage distinguishes between indolent SM (ISM) defined by a nearly normal life expectancy and advanced SM (AdvSM) defined by poor prognosis. In ISM, measurement of the bone mineral density (BMD) frequently reveals osteoporosis. In contrast, the clinical implication of an increased BMD and osteosclerosis remains unclear.

Methods: BMD was evaluated in 61 patients with mastocytosis (ISM, n = 29, 48%; AdvSM, n = 32, 52%). We correlated the prevalence of osteoporosis, increased BMD and osteosclerosis with clinical parameters, disease variant and prognosis.

Results: Osteoporosis was detected in 11/29 (38%) patients with ISM but only in 2/32 (6%) patients with AdvSM (p = 0.004). An increased BMD was detected in 1/29 (3%) patients with ISM and 24/32 (75%) patients with AdvSM (p < 0.001) while osteosclerosis was only detected in AdvSM patients (16/32, 50%). AdvSM patients with increased BMD had higher levels of bone marrow mast cell infiltration, higher serum tryptase and alkaline phosphatase levels compared to ISM as well as higher number of high-molecular risk mutations (p < 0.05). In addition, we found that the prognosis of AdvSM patients with increased BMD is inferior compared to those without increased BMD (median overall survival 3.6 years versus not reached, p = 0.031).

Conclusions: Osteoporosis is a common feature in ISM but not in AdvSM. An increased BMD is frequently present in AdvSM but not in ISM and is associated with more advanced disease and inferior outcome.
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http://dx.doi.org/10.1007/s00432-019-03119-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7085471PMC
April 2020

Simultaneous Multislice Diffusion-Weighted Imaging of the Kidneys at 3 T.

Invest Radiol 2020 04;55(4):233-238

From the Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Germany.

Purpose: The aim of this study was to compare respiratory-triggered diffusion-weighted imaging with simultaneous-multislice acceleration (SMS-RT-DWI) to a standard free-breathing echoplanar DWI (s-DWI) for 3 T renal imaging with respect to image quality and artifacts.

Materials And Methods: A total of 40 patients who had undergone renal magnetic resonance imaging were included in this retrospective analysis of a prospectively planned cohort study. All examinations were performed on a 3 T whole-body magnetic resonance system. Both s-DWI and SMS-RT-DWI were obtained and images were independently reviewed by 2 radiologists on a 5-point Likert scale with respect to overall preference and image quality, renal edge and parenchymal sharpness, cortico-medullary differentiation, and sequence-related artifacts. Furthermore, discernibility of renal lesions was assessed. The signal-to-noise ratio (SNR) was measured from SNR maps. The derived mean apparent diffusion coefficients were also compared. Qualitative parameters were assessed with the Wilcoxon rank-sum test, and quantitative parameters, with the Student t test.

Results: Overall image quality, renal edge, and parenchymal sharpness of SMS-RT-DWI were rated as superior to s-DWI by the readers, with fewer sequence-related artifacts (P < 0.01 for all). Lesion discernibility was significantly improved for SMS-RT-DWI (P < 0.01). Both readers preferred SMS-RT-DWI to s-DWI in all cases (40/40). The acquisition time for SMS-RT-DWI was 30% shorter than for s-DWI. Mean SNR heterogeneity of SMS-RT-DWI at b = 800 s/mm was statistically significantly lower than s-DWI, whereas mean SNR was significantly higher for SMS-RT-DWI. Mean apparent diffusion coefficient values from both sequences were comparably homogeneous throughout the kidneys.

Conclusion: Simultaneous multislice DWI of the kidney at 3 T with respiratory triggering yields substantially improved image quality and lesion discernibility compared with standard single-shot echoplanar DWI with a 30% reduction in scan acquisition time.
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http://dx.doi.org/10.1097/RLI.0000000000000637DOI Listing
April 2020
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