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PURPOSE: To apply Doppler US (DUS)–gated fetal cardiac cine MRI in clinical routine and investigate diagnostic performance in complex congenital heart disease (CHD) compared with that of fetal echocardiography. MATERIALS AND METHODS: In this prospective study (May 2021 to March 2022), women with fetuses with CHD underwent fetal echocardiography and DUS-gated fetal cardiac MRI on the same day. For MRI, balanced steady-state free precession cine images were acquired in the axial and optional sagittal and/or coronal orientations. Overall image quality was assessed on a four-point Likert scale (from 1 = nondiagnostic to 4 = good image quality). The presence of abnormalities in 20 fetal cardiovascular features was independently assessed by using both modalities. The reference standard was postnatal examination results. Differences in sensitivities and specificities were determined by using a random-effects model. RESULTS: The study included 23 participants (mean age, 32 years ± 5 [SD]; mean gestational age, 36 weeks ± 1). Fetal cardiac MRI was completed in all participants. The median overall image quality of DUS-gated cine images was 3 (IQR, 2.5–4). In 21 of 23 participants (91%), underlying CHD was correctly assessed by using fetal cardiac MRI. In one case, the correct diagnosis was made by using MRI only (situs inversus and congenitally corrected transposition of the great arteries). Sensitivities (91.8% [95% CI: 85.7, 95.1] vs 93.6% [95% CI: 88.8, 96.2]; P = .53) and specificities (99.9% [95% CI: 99.2, 100] vs 99.9% [95% CI: 99.5, 100]; P > .99) for the detection of abnormal cardiovascular features were comparable between MRI and echocardiography, respectively. CONCLUSION: Using DUS-gated fetal cine cardiac MRI resulted in performance comparable with that of using fetal echocardiography for diagnosing complex fetal CHD. Keywords: Pediatrics, MR-Fetal (Fetal MRI), Cardiac, Heart, Congenital, Fetal Imaging, Cardiac MRI, Prenatal, Congenital Heart Disease Clinical trial registration no. NCT05066399 Supplemental material is available for this article. © RSNA, 2023 See also the commentary by Biko and Fogel in this issue.

Rationale and Objectives To investigate the effects of a reduced field-of-view (rFOV) acquisition in diffusion-weighted magnetic resonance imaging of the pancreas. Materials and Methods We enrolled 153 patients who underwent routine clinical MRI work-up including respiratory-triggered diffusion-weighted single-shot echo-planar imaging (DWI) with full field-of-view (fFOV, 3 × 3 × 4 mm3 voxel size) and reduced field-of-view (rFOV, 2.5 × 2.5 × 3 mm3 voxel size) for suspected pancreatic pathology. Two experienced radiologists were asked to subjectively rate (Likert Scale 1–4) image quality (overall image quality, lesion conspicuity, anatomical detail, artifacts). In addition, quantitative image parameters were assessed (apparent diffusion coefficient, apparent signal to noise ratio, apparent contrast to noise ratio [CNR]). Results All subjective metrics of image quality were rated in favor of rFOV DWI images compared to fFOV DWI images with substantial-to-high inter-rater reliability. Calculated ADC values of normal pancreas, pancreatic pathologies and reference tissues revealed no differences between both sequences. Whereas the apparent signal to noise ratio was higher in fFOV images, apparent CNR was higher in rFOV images. Conclusion rFOV DWI provides higher image quality and apparent CNR values, favorable in the analysis of pancreatic pathologies.

The aim of this study was to compare a new compressed sensing (CS) method for T2-weighted propeller acquisitions (T2CS) with conventional T2-weighted propeller sequences (T2conv) in terms of achieving a higher image quality, while reducing the acquisition time.Male participants with a clinical suspicion of prostate cancer were prospectively enrolled and underwent prostate magnetic resonance imaging at 3 T. Axial and sagittal images of the T2conv sequence and the T2CS sequence were acquired. Sequences were qualitatively assessed by 2 blinded radiologists concerning artifacts, image-sharpness, lesion conspicuity, capsule delineation, and overall image quality using 5-point Likert items ranging from 1 (nondiagnostic) to 5 (excellent). The apparent signal-to-noise ratio and apparent contrast-to-noise ratio were evaluated. PI-RADS scores were assessed for both sequences. Statistical analysis was performed by using Wilcoxon signed rank test and paired samples t test. Intrarater and interrater reliability of qualitative image evaluation was assessed using intraclass correlation coefficient (ICC) estimates.A total of 29 male participants were included (mean age, 66 ± 8 years). The acquisition time of the T2CS sequence was respectively 26% (axial plane) and 24% (sagittal plane) shorter compared with the T2conv sequence (eg, axial: 171 vs 232 seconds; P0.001). In the axial plane, the T2CS sequence had fewer artifacts (4 [4-4.5] vs 4 [3-4]; P0.001), better image-sharpness (4 [4-4.5] vs 3 [3-3.5]; P0.001), better capsule delineation (4 [3-4] vs 3 [3-3.5]; P0.001), and better overall image quality (4 [4-4] vs 4 [3-4]; P0.001) compared with the T2conv sequence. The ratings of lesion conspicuity were similar (4 [4-4] vs 4 [3-4]; P = 0.166). In the sagittal plane, the T2CS sequence outperformed the T2conv sequence in the categories artifacts (4 [4-4] vs 3 [3-4]; P0.001), image sharpness (4 [4-5] vs 4 [3-4]; P0.001), lesion conspicuity (4 [4-4] vs 4 [3-4]; P = 0.002), and overall image quality (4 [4-4] vs 4 [3-4]; P = 0.002). Capsule delineation was similar between both sequences (3 [3-4] vs 3 [3-3]; P = 0.07). Intraobserver and interobserver reliability for qualitative scoring were good (ICC intra: 0.92; ICC inter: 0.86). Quantitative analysis revealed a higher apparent signal-to-noise ratio (eg, axial: 52.2 ± 9.7 vs 22.8 ± 3.6; P0.001) and a higher apparent contrast-to-noise ratio (eg, axial: 44.0 ± 9.6 vs 18.6 ± 3.7; P ≤ 0.001) of the T2CS sequence. PI-RADS scores were the same for both sequences in all participants.CS-accelerated T2-weighted propeller acquisition had a superior image quality compared with conventional T2-weighted propeller sequences while significantly reducing the acquisition time.

Compressed sensing (CS) is a method to accelerate MRI acquisition by acquiring less data through undersampling of k-space. In this prospective study we aimed to evaluate whether a three-dimensional (3D) isotropic proton density-weighted fat saturated sequence (PDwFS) with CS can replace conventional multidirectional two-dimensional (2D) sequences at 1.5 Tesla. 20 patients (45.2 ± 20.2 years; 10 women) with suspected internal knee damage received a 3D PDwFS with CS acceleration factor 8 (acquisition time: 4:11 min) in addition to standard three-plane 2D PDwFS sequences (acquisition time: 4:05 min + 3:03 min + 4:46 min = 11:54 min) at 1.5 Tesla. Scores for homogeneity of fat saturation, image sharpness, and artifacts were rated by two board-certified radiologists on the basis of 5-point Likert scales. Based on these ratings, an overall image quality score was generated. Additionally, quantitative contrast ratios for the menisci (MEN), the anterior (ACL) and the posterior cruciate ligament (PCL) in comparison with the popliteus muscle were calculated. The overall image quality was rated superior in 3D PDwFS compared to 2D PDwFS sequences (14.45 ± 0.83 vs. 12.85 ± 0.99; p 0.01), particularly due to fewer artifacts (4.65 ± 0.67 vs. 3.65 ± 0.49; p 0.01) and a more homogeneous fat saturation (4.95 ± 0.22 vs. 4.55 ± 0.51; p 0.01). Scores for image sharpness were comparable (4.80 ± 0.41 vs. 4.65 ± 0.49; p = 0.30). Quantitative contrast ratios for all measured structures were superior in 3D PDwFS (MEN: p 0.05; ACL: p = 0.06; PCL: p = 0.33). In one case a meniscal tear was only diagnosed using multiplanar reformation of 3D PDwFS, but it would have been missed on standard multiplanar 2D sequences. An isotropic fat-saturated 3D PD sequence with CS enables fast and high-quality 3D imaging of the knee joint at 1.5 T and may replace conventional multiplanar 2D sequences. Besides faster image acquisition, the 3D sequence provides advantages in small structure imaging by multiplanar reformation. · 3D PDwFS with compressed sensing enables knee imaging that is three times faster compared to multiplanar 2D sequences. · 3D PDwFS with compressed sensing provides high-quality knee imaging at 1.5 T. · Isotropic 3D sequences provide advantages in small structure imaging by using multiplanar reformations.· Endler CH, Faron A, Isaak A et al. Fast 3D Isotropic Proton Density-Weighted Fat-Saturated MRI of the Knee at 1.5 T with Compressed Sensing: Comparison with Conventional Multiplanar 2D Sequences. Fortschr Röntgenstr 2021; 193: 813 - 821.ZIEL: Compressed Sensing (CS) ist eine Signalverarbeitungstechnik, mithilfe derer man durch Unterabtasten des k-Raums weniger Daten akquirieren und so MRT-Aufnahmen beschleunigen kann. Ziel dieser prospektiven Studie war die Klärung der Frage, ob eine 3-dimensionale (3D) isotrope protonengewichtete fettgesättigte Sequenz (PDwFS) mit CS konventionelle multidirektionale 2-dimensionale (2D) Sequenzen bei 1,5 T ersetzen kann. 20 Patienten (45,2 ± 20,2 Jahre; 10 Frauen) mit Verdacht auf Kniebinnenschaden erhielten am 1,5T-MRT zusätzlich zu den konventionellen, in 3 Ebenen angefertigten 2D-PDwFS (Akquisitionszeit: 4:05min + 3:03min + 4:46min = 11:54 min) eine 3D-PDwFS mit CS-Beschleunigungsfaktor 8 (Akquisitionszeit: 4:11 min). Die Homogenität der Fettunterdrückung, die Bildschärfe und Artefakte wurden anhand von 5-Punkt-Likert-Skalen durch 2 erfahrene Radiologen beurteilt. Anhand der so vergebenen Punkte wurde die Gesamtbildqualität ermittelt. Zusätzlich wurden quantitative Kontrastverhältnisse für die Menisken (MEN), das vordere (ACL) und das hintere Kreuzband (PCL) im Vergleich zum Musculus popliteus errechnet. Die Gesamtbildqualität wurde in der 3D-PDwFS höher als in den 2D-PDwFS-Sequenzen bewertet (14,45 ± 0,83 vs. 12,85 ± 0,99; p 0,01), insbesondere aufgrund weniger Artefakte (4,65 ± 0,67 vs. 3,65 ± 0,49; p 0,01) und einer homogeneren Fettunterdrückung (4,95 ± 0,22 vs. 4,55 ± 0,51; p 0,01). Die Bildschärfe ergab keinen signifikanten Unterschied (4,80 ± 0,41 vs. 4,65 ± 0,49; p = 0,30). Die quantitativen Kontrastverhältnisse waren in den 3D-PDwFS für alle gemessenen Strukturen höher als in den 2D-PDwFS (MEN: p 0,05; ACL: p = 0,06; PCL: p = 0,33). In einem Fall konnte ein Meniskusriss lediglich mithilfe einer multiplanaren Reformatierung der 3D-PDwFS diagnostiziert werden und wäre auf den konventionellen multiplanaren 2D-Sequenzen übersehen worden. Eine isotrope fettgesättigte 3D-PD-Sequenz mit CS ermöglicht eine schnelle und qualitativ hochwertige 3D-Bildgebung des Kniegelenks bei 1,5 T und könnte konventionelle multiplanare 2D-Sequenzen ersetzen. Neben einer schnelleren Bildakquise bietet die 3D-Sequenz Vorteile in der Bildgebung kleiner Strukturen. · 3D-PDwFS mit Compressed Sensing ermöglicht eine 3-fach schnellere Knie-Bildgebung verglichen mit multiplanaren 2D-Sequenzen.. · 3D-PDwFS mit Compressed Sensing ermöglicht eine qualitativ hochwertige Knie-Bildgebung bei 1,5 T.. · Isotrope 3D-Sequenzen bieten Vorteile in der Darstellung kleiner Strukturen durch die Möglichkeit der multiplanaren Reformation..

Objective The assessment of fatty infiltration and edema in the musculature of patients with neuromuscular diseases (NMDs) typically requires the separate performance of T-1-weighted and fat-suppressed T-2-weighted sequences. T-2-weighted Dixon turbo spin echo (TSE) enables the generation of T-2-weighted fat- and water-separated images, which can be used to assess both pathologies simultaneously. The present study examines the diagnostic performance of T-2-weighted Dixon TSE compared with the standard sequences in 10 patients with NMDs and 10 healthy subjects. Methods Whole-body magnetic resonance imaging was performed including T-1-weighted Dixon fast field echo, T-2-weighted short-tau inversion recovery, and T-2-weighted Dixon TSE. Fatty infiltration and intramuscular edema were rated by 2 radiologists using visual semiquantitative rating scales. To assess intermethod and interrater agreement, weighted Cohen's coefficients were calculated. Results The ratings of fatty infiltration showed high intermethod and high interrater agreement (T-1-weighted Dixon fast field echo vs T-2-weighted Dixon TSE fat image). The evaluation of edematous changes showed high intermethod and good interrater agreement (T-2-weighted short-tau inversion recovery vs T-2-weighted Dixon TSE water image). Conclusions T-2-weighted Dixon TSE imaging is an alternative for accelerated simultaneous grading of whole-body skeletal muscle fat infiltration and edema in patients with NMDs.

ObjectivesTo evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation.MethodsSix-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used acceleration based on SENSE with a total acceleration factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used acceleration based on a combination of CS with SENSE with a total acceleration factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment.ResultsTotal scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%).ConclusionCS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts.Strengths of this studyCompressed sensing allows accelerated imaging with reduction of motion artifacts without alteration of quantitative measurementsRobust results in fat and iron quantification in a heterogeneous patient cohortLimitations of this studyNo histopathological validation of the MR findings was performedThe study was not performed at different field strengths

To evaluate the performance of a novel camera-based breathing navigation system in respiratory-triggered (CRT) 3D-magnetic resonance cholangiopancreatography (MRCP) at 3T MRI.Two 3D-MRCP data sets were acquired subsequently within one imaging session with traditional respiratory belt- (BRT) or camera- (CRT) based triggering in 28 patients. Overall image quality, blurring, motion artifacts and discernibility of the pancreaticobiliary tree (PBT) structures were scored on a 4-point scale retrospectively by 2 radiologists. The contrast ratio between the common bile duct and its adjacent tissue was measured by region-of-interest (ROI) analysis. The signal intensity increase at the duct boundaries was quantified by line profiles to objectify blurring and motion artifacts. The extracted respiratory signal curves were analyzed for signal quality and trigger timing.Total scan time was 72 s for both acquisitions. CRT yielded significantly better ratings in image quality, background suppression, blurring and discernibility of PBT structures compared to BRT. Contrast ratios were significantly higher in CRT (0.94 ± 0.03) than in BRT (0.93 ± 0.03) exams; paired t test P = 0.0017. Line profile slopes through the common bile duct revealed significantly higher values in CRT (42.23 ± 8.74% of maximum intensity/mm) compared to BRT (36.06 ± 8.96% of maximum intensity/mm; paired t test P 0.0001). Camera-derived respiratory signal curves showed a higher SNR, lower standard deviation of the signal amplitude and less incorrect triggering than the respiratory belt-derived respiratory signal curves.Camera-based respiratory triggering significantly improves image quality of 3D-MRCP compared to conventional respiratory belt triggering.