To investigate the potential of combining Compressed Sensing (CS) and a newly developed AI-based super resolution reconstruction prototype consisting of a series of convolutional neural networks (CNN) for a complete five-minute 2D knee MRI protocol. In this prospective study, 20 volunteers were examined using a 3T-MRI-scanner (Ingenia Elition X, Philips). Similar to clinical practice, the protocol consists of a fat-saturated 2D-proton-density-sequence in coronal, sagittal and transversal orientation as well as a sagittal T1-weighted sequence. The sequences were acquired with two different resolutions (standard and low resolution) and the raw data reconstructed with two different reconstruction algorithms: a conventional Compressed SENSE (CS) and a new CNN-based algorithm for denoising and subsequently to interpolate and therewith increase the sharpness of the image (CS-SuperRes). Subjective image quality was evaluated by two blinded radiologists reviewing 8 criteria on a 5-point Likert scale and signal-to-noise ratio calculated as an objective parameter. The protocol reconstructed with CS-SuperRes received higher ratings than the time-equivalent CS reconstructions, statistically significant especially for low resolution acquisitions (e.g., overall image impression: 4.3 ± 0.4 vs. 3.4 ± 0.4, p < 0.05). CS-SuperRes reconstructions for the low resolution acquisition were comparable to traditional CS reconstructions with standard resolution for all parameters, achieving a scan time reduction from 11:01 min to 4:46 min (57 %) for the complete protocol (e.g. overall image impression: 4.3 ± 0.4 vs. 4.0 ± 0.5, p < 0.05). The newly-developed AI-based reconstruction algorithm CS-SuperRes allows to reduce scan time by 57% while maintaining unchanged image quality compared to the conventional CS reconstruction.

To evaluate if real-time dose visualisation during computed tomography (CT)-guided interventions leads to a reduction in radiation dose to participating radiologists. The individual radiation dose radiologists are exposed to during CT interventions was measured using dedicated dosimeters (RaySafe i2-system, Unfors RaySafe GmbH, Billdal, Sweden) worn over the usual radiation protective apron. Initially, only the total radiation dose was measured, without visualisation (control group). In the following study period, the radiation dose was shown to participants on a live screen in real-time (experimental group). In both groups, the dose was recorded in 1-second intervals. The results collected were evaluated by comparison using descriptive statistics and mixed-effect models. In particular, the variables experience, gender, role, and position during the intervention were analysed. In total, 517 measurements of 304 interventions (n=249 with and n=268 without live screen) performed by 29 radiologists acting as interventionalists or assistants were analysed. All CT-guided interventions were performed percutaneously, the majority of which (n=280) were microwave ablations (MWA). Radiation doses in the group without visualisation were comparable with usual dose rates for the corresponding intervention type. The mean total radiation dose was reduced by 58.1% (11.6 versus 4.86 μSv) in the experimental group (p=0.034). The highest reduction of 78.5% (15.55 versus 3.35 μSv) was observed in radiologists with the role of assistant (p=0.002). Sub-analysis showed significant dose reduction (p<0.0001) for the use of live screen in general; considering all variables, the role "assistant" alone had a statistically significant influence (p=0.002). The real-time visualisation of active radiation dose during CT interventions leads to a relevant reduction in radiation dose to participating radiologists.

Objectives: The purpose of this study was to assess whether a 3-min 2D knee protocol can meet the needs for clinical application if using a SuperResolution reconstruction approach. Methods: In this prospective study, a total of 20 volunteers underwent imaging of the knee using a 3T MRI scanner (Philips Ingenia Elition X 3.0T, Philips). The imaging protocol, consisting of a fat-saturated 2D proton density sequence in coronal, sagittal, and transverse orientations, as well as a sagittal T1-weighted sequence, was acquired with standard and ultra-low resolution. The standard sequences were reconstructed using an AI-assisted Compressed SENSE method (SmartSpeed). The ultra-low-resolution sequences have been reconstructed using a vendor-provided prototype. Four experienced readers (two radiologists and two orthopedic surgeons) evaluated the sequences for image quality, anatomical structures, and incidental pathologies. The consensus evaluation of two different experienced radiologists specialized in musculoskeletal imaging served as the gold standard. Results: The acquisition time for the entire protocol was 11:01 min for standard resolution and 03:36 min for ultra-low resolution. In the overall assessment, CS-SuperRes-reconstructed sequences showed slightly improved accuracy and increased specificity compared to the standard CS-AI method (0.87 vs. 0.86 and 0.9 vs. 0.87, respectively), while the standard method exhibited a higher sensitivity (0.73 vs. 0.57). Overall, 24 out of 40 pathologies were detected in the ultra-low-resolution images compared to 26 in the standard images. Conclusions: The CS-SuperRes method enables a 2D knee protocol to be completed in 3 min, with improved accuracy compared to the clinical standard.

Background: Skeletal bone age assessment for medical reasons is usually performed by conventional x-ray with use of ionizing radiation. Few pilot studies have shown the possible use of magnetic resonance imaging (MRI). Purpose: To comprehensively evaluate feasibility and value of MRI for skeletal bone age (SBA) assessment in healthy male children. Materials and Methods: In this prospective cross-sectional study, 63 male soccer athletes with mean age of 12.35 ± 1.1 years were examined. All participants underwent 3.0 Tesla MRI with coronal T1-weighted turbo spin echo (TSE), coronal proton density (PD)–weighted turbo spin echo (TSE), and T1-weighted three-dimensional (3D) volume interpolated breath-hold examination (VIBE) sequence. Subsequently, SBA was assessed by 3 independent blinded radiologists with different levels of experience using the common Greulich-Pyle (GP) atlas and the Tanner-Whitehouse (TW2) method. Results: In a mean total acquisition time of 5:04 ± 0:47 min, MR image quality was sufficient in all cases. MRI appraisal was significantly faster (P < 0.0001) by GP with mean duration of 1:22 ± 0:08 min vs. 7:39 ± 0:28 min by TW. SBA assessment by GP resulted in mean age of 12.8 ± 1.2 years, by TW 13.0 ± 1.4 years. Interrater reliabilities were excellent for both GP (ICC = 0.912 (95% confidence interval [CI] = 0.868–0.944) and TW (ICC = 0.988 (95% CI = 0.980–0.992) and showed statistical significance (P < 0.001). Subdivided, for GP, ICCs were 0.822 (95% CI = 0.680–0.907) and 0.843 (95% CI = 0.713–0.919) in Under 12 and Under 14 group. For TW, ICCs were 0.978 (95% CI = 0.958–0.989) in Under 12 and 0.979 (95% CI = 0.961–0.989) in Under 14 group. Conclusion: MRI is a clinically feasible, rapidly evaluable method to assess skeletal bone age of healthy male children. Using the Greulich-Pyle (GP) atlas or the Tanner-Whitehouse (TW2) method, reliable results are obtained independent of the radiologist's experience level.

Die obstruktive Uropathie ist ein häufiges Krankheitsbild. Mögliche Ursachen sind Konkremente, funktionelle und neurogene Störungen, Anlagevarianten sowie entzündliche und stenosierende Prozesse. Der Nachweis dieser Ursachen, aber auch der Ausschluss bzw. Beweis eines Harnstaus und die Therapieplanung sind Ziele der bildgebenden Diagnostik. Die dazu eingesetzten Verfahren werden in diesem Beitrag mit ihren Vor- und Nachteilen vorgestellt. Article published online: 02 December 2024 © 2024. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Zielsetzung Umfassende Evaluation der Durchführbarkeit und Wertigkeit der Magnetresonanztomographie (MRT) zur Skelettalterbestimmung von gesunden männlichen Jugendlichen. Material und Methoden Im Rahmen dieser Querschnittsstudie wurden im November 2019 N = 63 männliche Fußballspieler ohne chronische Vorerkrankungen im Alter von 10 – 13 Jahren (Mittelwert: 12,35 ± 1,1 Jahre) an einem 3 Tesla MRT untersucht. Es erfolgte die Akquisition dreier nativer Sequenzen: (1) Coronare T1-gewichtete TSE, (2) Coronare PD-gewichtete TSE und (3) T1-gewichtete 3D VIBE. Anschließend wurden die MRTs von drei verblindeten Radiologen mit unterschiedlichen Erfahrungslevels unabhängig ausgewertet: (1) Kinderradiologe, (2) > 20 und (3) < 3 Jahre Erfahrung in muskuloskelettaler Radiologie. Die Skelettalterbestimmung erfolgte mittels der Greulich-Pyle (GP) Atlas und der Tanner-Whitehouse (TW2) Scoring Methode. Deskriptive Statistiken, Interrater-Reliabilitäten, T-Tests, Wilcoxon-Mann-Whitney-U-Tests und Bland-Altman Plots wurden berechnet. Ergebnisse Es wurden keine Komplikationen dokumentiert. Bei einer durchschnittlichen Untersuchungsdauer von 5 : 04 ± 0 : 47 Minuten (Bereich: 4 : 35 – 7 : 21 Minuten) war die Bildqualität in 63/63 Untersuchungen (100%) ausreichend. Die Auswertung mit GP war mit durchschnittlich 1 : 22 ± 0 : 04 Minuten (Bereich: 1 : 11 – 1 : 32 Minuten) gegenüber 7 : 39 ± 0 : 06 Minuten (Bereich: 7 : 04 – 8 : 26 Minuten) mit TW schneller (p < 0,0001). Nach der GP Methode lag das ermittelte durchschnittliche Skelettalter bei 12,8 ± 1,2 Jahren, nach TW bei 13,0 ± 1,4 Jahren. Mit einem ICC = 0,912 für GP (95%-CI = [0,868; 0,944], α = 0,915) und ICC = 0,988 für TW (95%-CI = [0,980; 0,992], α = 0,989) ergaben sich für beide Methoden exzellente Interrater-ReIiabilitäten (p < 0,001). Schlussfolgerungen Die MRT stellt ein gut durchführbares strahlungsfreies Verfahren zur Skelettalterbestimmung von gesunden männlichen Jugendlichen dar. Unter Verwendung der gängigsten Methoden (GP und TW2) ermöglicht sie unabhängig der jeweiligen Erfahrung der Radiologen eine reliable Auswertung. Publication Date: 11 May 2021 (online) © 2021. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany