BACKGROUND: Ebstein's anomaly (EA) is a congenital heart disorder involving tricuspid valve dysplasia and right heart abnormalities resulting in severe tricuspid regurgitation (TR). Multiple techniques assess regurgitati...BACKGROUND: Ebstein's anomaly (EA) is a congenital heart disorder involving tricuspid valve dysplasia and right heart abnormalities resulting in severe tricuspid regurgitation (TR). Multiple techniques assess regurgitation severity, but their correlation with EA severity markers remains unclear. PURPOSE: To compare MRI techniques for quantifying TR and regurgitant volume (RVol) in adults with EA. STUDY TYPE: Retrospective. SUBJECTS: Thirty-three adult patients with EA (15 males/18 females). FIELD STRENGTH/SEQUENCE: 3T or 1.5-Tesla, 2D-phase contrast (2D-PC gradient echo) and 4D-flow (gradient echo). ASSESSMENT: RVol was measured using three methods: (1) 2D-indirect: subtraction of systolic pulmonary artery (PA) forward flow (2D-PC) from functional right ventricular stroke volume (fRVSV); (2) 4D-indirect: subtraction of PA systolic forward flow from tricuspid diastolic forward flow using 4D-flow; (3) 4D-direct: direct jet measurement with 4D-flow. Correlations were evaluated between RVol and severity markers (left ventricular ejection fraction [LVEF], functional right ventricular end-diastolic volume [fRVEDV], fRV/LV ratio, severity index volume, total right/left volume index, fRVEF). STATISTICAL TESTS: Pearson or Spearman correlation coefficients (p < 0.05) significant. RESULTS: The 4D-direct method had the highest correlation with the mean RVol (2D-indirect: r = 0.93, 4D-indirect: r = 0.93; 4D-direct: r = 0.95) and with severity markers: total right/left volume index (0.84, 0.64, 0.87), the fRVEDV (0.66, 0.58, 0.71), fRV/LVratio (0.81, 0.75, 0.87), and severity index volume (0.45, 0.59, 0.66). DATA CONCLUSION: 4D-flow enables intrinsic RVol quantification independent of fRV segmentation, with the direct jet method outperforming indirect approaches. TECHNICAL EFFICACY: Stage 2.
BACKGROUND: Dp140-related mutations associate with neurodevelopmental impairments in Duchenne muscular dystrophy (DMD), their effects on cortical similarity network organization remain unclear. PURPOSE: To characterize a...BACKGROUND: Dp140-related mutations associate with neurodevelopmental impairments in Duchenne muscular dystrophy (DMD), their effects on cortical similarity network organization remain unclear. PURPOSE: To characterize alterations in morphometric similarity networks (MSN) in DMD with different Dp140 genotypes, assess their associations with clinical phenotypes and gene expression. STUDY TYPE: Prospective. POPULATION: One hundred and fifteen boys with DMD (75 Dp140-: 9.63 ± 2.25 years; 40 Dp140+: 10.99 ± 2.25 years) and 69 healthy controls (all male, 10.65 ± 2.43 years). FIELD STRENGTH/SEQUENCE: Gradient echo at 3 T. ASSESSMENT: MRI were processed using FreeSurfer and GRETNA. Behavior data were based on Wechsler Intelligence Scale for children-Fourth edition while transcriptional profiles were from the Allen Human Brain Atlas. STATISTICAL TESTS: Independent T-tests, chi-square tests, general linear models, permutation testing, multivariable linear regression, mediation analyses, partial least squares regression, spatial permutation tests (Spin test), Gene Ontology enrichment analysis and cell-type analysis. FDR-corrected p < 0.05 and p < 0.05 were considered significant. RESULTS: Dp140- subgroup had lower working memory index (WMI) than Dp140+ DMD (81.63 ± 15.48 vs. 90.78 ± 15.31; p = 0.01, Cohen's d = 0.179). Dp140- DMD showed reduced cortical similarity in bilateral lateral prefrontal cortex and parietal cortex regions, increased modular segregation (Hedge's g = -0.298, 95% CI [-0.408, -0.187]), and more hubs loss within frontal parietal network (FPN). The indirect effect of Dp140 genotype on WMI through mean FPN cortical similarity was significant (β = -0.121, p = 0.03, 95% CI [-0.282, -0.001]). The Dp140-specific MSN changes were spatially associated with transcriptional profile, which are enriched in neuronal projection development pathways of excitatory neurons (p < 0.05). DATA CONCLUSION: By linking genotype, neuroimaging, and transcriptional data, these findings offer further insight into mechanisms possibly involved in working memory deficits among Dp140- DMD. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 2.
BACKGROUND: The diffusion tensor image analysis along the perivascular space (DTI-ALPS) index is an established term, and ongoing research aims to explore underlying mechanisms. HYPOTHESIS: DTI-ALPS measures are influenc...BACKGROUND: The diffusion tensor image analysis along the perivascular space (DTI-ALPS) index is an established term, and ongoing research aims to explore underlying mechanisms. HYPOTHESIS: DTI-ALPS measures are influenced by subject-specific orientational differences of the projection and association fibers. STUDY TYPE: Prospective. SUBJECTS: Forty-four healthy adults (age: 22.1 ± 1.9 years; 19 males). FIELD STRENGTH/SEQUENCE: 3 T/diffusion-weighted spin-echo echo-planar imaging. ASSESSMENT: DTI-ALPS index was calculated by three methods using delineations of four observers (17-, 4-, 5-, 3-years of experience): (1) following vector registration to an atlas (Method 1); (2) after achieving zero projection for the relevant tracts by x-axis rotation (Method 2); and (3) based on the second and third diffusion tensor eigenvalues (Method 3). Effects of deviation from the expected anatomical orientation of ALPS-associated tracts were also analyzed. STATISTICAL TESTS: Intraclass correlation coefficients (ICCs) were calculated among observers and methods. Friedman and Wilcoxon tests were used, respectively, for inter-method and inter-hemispheric comparisons. Spearman correlation and multiple-linear regression assessed whether tract orientation deviation introduced bias in ALPS estimation. Significance level was p < 0.05. RESULTS: Inter-observer ICCs were excellent for average-measures (≥ 0.90) and mostly good for single-measures (0.90 > ICC ≥ 0.80). ALPS values differed significantly among methods, with significantly higher values for methods reducing bias due to deviation from the expected anatomical orientation of ALPS-associated tracts (bilateral DTI-ALPS index averaged across observers: 1.49 ± 0.13 vs. 1.59 ± 0.13 and 1.66 ± 0.13 for Methods 1-3 respectively). Left DTI-ALPS index was significantly higher than the right for all 3 methods (averaged values across observers: 1.54 ± 0.14 vs. 1.44 ± 0.13; 1.65 ± 0.14 vs. 1.52 ± 0.13; 1.73 ± 0.14 vs. 1.59 ± 0.13). Inter-method ICCs showed good-to-excellent consistency across all method pairs (≥ 0.80), but absolute ICCs were not always acceptable. Deviations from the expected orientation of ALPS-associated tracts significantly affected ALPS values, especially for the left projection pathway (Spearman's rho: -0.503 to -0.376 for the bilateral index). DATA CONCLUSION: DTI-ALPS measures based on diffusion along Cartesian axes are influenced by off-axis orientation of ALPS-associated fibers, indicating that the DTI-ALPS index is statistically significantly confounded by non-glymphatic factors. TECHNICAL EFFICACY: Stage 1.
BACKGROUND: The impact of deep learning (DL) reconstruction and segmentation on MRI radiomics stability has not been fully assessed. PURPOSE: To investigate the effects of acquisition, reconstruction, and segmentation on...BACKGROUND: The impact of deep learning (DL) reconstruction and segmentation on MRI radiomics stability has not been fully assessed. PURPOSE: To investigate the effects of acquisition, reconstruction, and segmentation on the reproducibility and variability of radiomic features in abdominal MRI. STUDY TYPE: Prospective. POPULATION: 37 volunteers (22 men; mean age ± standard deviation, 37.4 ± 11.0 years). FIELD STRENGTH/SEQUENCE: 3.0-T; axial turbo spin echo T2-weighted image, and fat-suppressed T2-weighted image using a half-Fourier acquisition single-shot turbo spin echo technique, each acquired four times with conventional or accelerated techniques, reconstructed with standard or DL algorithms. ASSESSMENT: Regions of interest were automatically generated by a DL neural network for liver, spleen, and right and left kidneys, followed by manual correction. We extracted 107 features using PyRadiomics after z-score normalization. STATISTICAL TESTS: The reproducibility between acquisitions, reconstructions, and segmentations was evaluated using intraclass correlation coefficient (ICC) and concordance correlation coefficient (CCC). The variability among the four scans was assessed by coefficient of variation (CV) and quartile coefficient of dispersion (QCD). p < 0.05 was considered significant. RESULTS: The mean ICC (0.518-0.608; 0.606-0.681) and CCC (0.515-0.603; 0.601-0.680) values were low for both manual and automatic segmentation regardless of image acquisition and reconstruction, using conventional acquisition with standard reconstruction as reference. The mean ICC (0.535-0.713) and CCC (0.531-0.714) values were low between manual and automatic segmentation, regardless of image acquisition and reconstruction. The median CV (10.0%-17.5%; 8.9%-15.5%) and QCD (5.3%-8.5%; 5.1%-8.3%) values were moderate but still adequate for both manual and automatic segmentation among different scans. CONCLUSION: Given the substantial impact of accelerated acquisition and DL reconstruction on the robustness of radiomics features in abdominal MRI, caution should be exercised when utilizing images with different acquisition and reconstruction techniques in radiomics analysis. The automatic segmentation cannot replace manual segmentation due to insufficient robustness of radiomics features. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 1.
BACKGROUND: Xenon MRI is increasingly used to evaluate patients with interstitial lung disease (ILD) and pulmonary hypertension (PH), both of which are common manifestations of systemic sclerosis (SSc). As such, Xe-MRI m...BACKGROUND: Xenon MRI is increasingly used to evaluate patients with interstitial lung disease (ILD) and pulmonary hypertension (PH), both of which are common manifestations of systemic sclerosis (SSc). As such, Xe-MRI may be suited to interrogate lung function impairment in SSc. PURPOSE: To characterize xenon MRI signatures in SSc, toward evaluating the utility of xenon MRI as a method to elucidate mechanisms of regional lung function impairment in this population. STUDY TYPE: Prospective. POPULATION: Of 25 participants initially imaged, 21 participants (18 females) with SSc were included. Sixteen healthy volunteers (13 females) were enrolled. FIELDSTRENGTH/SEQUENCE: 3 T, 1-point Dixon imaging using xenon MRI. ASSESSMENT: Xenon MRI measures including ventilation defect percent, membrane uptake, red blood cell (RBC) transfer, RBC defect percent, and RBC oscillation amplitude were generated. Measures were compared across healthy and SSc groups and correlated with standard clinical measures, including demographics, pulmonary function tests, CT lung density measures, and pulmonary artery pressure. STATISTICAL TESTS: Due to a small number of male participants, statistical analysis was limited to female participants. Wilcoxon, t-tests, or Fisher's exact tests were used to compare between healthy and SSc groups. Pearson's correlation was used to correlate xenon MRI with clinical measures. p < 0.05 was considered significant. RESULTS: Despite a relatively mild burden of pulmonary disease, SSc participants exhibited significantly lower RBC/Membrane ratio (0.25 [IQR, 0.10] vs. 0.34 [0.05]) and RBC transfer (0.22 ± 0.07 vs. 0.28 ± 0.07), and significantly greater RBC defect percent (22.8 [IQR, 16.9] vs. 11.9 [13.7]) compared to healthy volunteers. DATA CONCLUSION: Xenon MRI measures, including RBC transfer, RBC/Membrane, and RBC defect percent were markedly different in female SSc patients compared to age-matched healthy volunteers, suggesting that xenon MRI may be an effective method for examining regional impairments to pulmonary gas exchange in SSc. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 2.
BACKGROUND: Ultrashort echo time (UTE) MRI overcomes the low signal intensity and short T* of pulmonary tissues, improving image quality. Abnormally low UTE signal intensities are associated with hallmarks of cystic fibr...BACKGROUND: Ultrashort echo time (UTE) MRI overcomes the low signal intensity and short T* of pulmonary tissues, improving image quality. Abnormally low UTE signal intensities are associated with hallmarks of cystic fibrosis (CF), including gas trapping and lung hyperexpansion. PURPOSE: To explore short-term repeatability and sensitivity to treatment of low signal volume (LSV) from UTE MRI in pediatric CF. STUDY-TYPE: Single-site, retrospective, longitudinal. SUBJECTS: Thirteen participants with stable CF (6M/7F, median age = 15 years old) were scanned at baseline and 1-month to evaluate short-term repeatability. Subsequently, 14 CF participants (7M/7F median age = 16 years old) were scanned pre- and 1-month post-initiation of elexacaftor/tezacaftor/ivacaftor (ETI). FIELD STRENGTH/SEQUENCE: Three-dimensional stack-of-spirals for UTE, 2-dimensional gradient-echo for hyperpolarized xenon (Xe-MRI), 3-dimensional gradient-echo for thoracic cavity estimation at 3 T. ASSESSMENT: LSV was analyzed from UTE MRI. Same-day spirometry, multiple-breath washout, and Xe-MRI were also performed to compare to LSV. STATISTICAL TESTS: Differences were assessed with the Wilcoxon matched-pairs signed-rank test. Bland-Altman analysis and the Intraclass Correlation Coefficient (ICC) were used to assess 1-month repeatability in stable CF. Relationships between measures were assessed with Spearman correlation. p < 0.05 was considered significant. RESULTS: Baseline LSV was correlated with forced expiratory volume in 1 s (FEV), FEV to forced vital capacity ratio (FEV/FVC), lung clearance index (LCI), and ventilation defect percent (VDP) (all |ρ| ≥ 0.50). LSV was not significantly different after 1-month (20.1 [10.9-25.5]% vs. 21.7 [12.7-28.2]%, p = 0.4548) in stable pediatric CF with Bland-Altman bias < 1% and ICC = 0.93. LSV was significantly reduced from 18.8 [12.0-30.3]% to 16.4 [7.8-19.6]% after 1-month of ETI and correlated with absolute differences in FEV, FEV/FVC, LCI, and VDP (all |ρ| ≥ 0.59). DATA CONCLUSION: LSV analysis was feasible and repeatable in pediatric CF over a 1-month period. LSV was significantly reduced 1-month after ETI treatment, indicating sensitivity to reduced gas trapping, hyperexpansion, and obstruction. EVIDENCE LEVEL: 4. TECHNICAL EFFICACY: 1.
BACKGROUND: MRI is essential for diagnosing and monitoring neurological diseases. Conventional protocols require multiple sequences to obtain complementary contrasts, increasing scan time, cost, and tolerability. Generat...BACKGROUND: MRI is essential for diagnosing and monitoring neurological diseases. Conventional protocols require multiple sequences to obtain complementary contrasts, increasing scan time, cost, and tolerability. Generating multiple contrasts from a single acquisition may streamline workflow while maintaining clinical utility. PURPOSE: To train attention-based convolutional neural networks (ACNNs) to generate clinical-quality Fluid-Attenuated-Inversion-Recovery (FLAIR), Magnetization-Prepared-Rapid-Gradient-Echo (MPRAGE), R2* maps, and derived contrasts from a single Gradient Echo Plural Contrast Imaging (GEPCI) acquisition. STUDY TYPE: Retrospective. POPULATION: 43 MRI scans from individuals with multiple sclerosis (25/18 F/M, 49 ± 11 years-of-age). FIELD STRENGTH/SEQUENCE: 3 T MRI, 3D GEPCI, MPRAGE, and FLAIR. ASSESSMENT: Technical quality of AI-generated contrasts was evaluated against directly acquired MRI using structural similarity index (SSIM). Clinical image quality was assessed by physicians. Lesion volumes and counts were obtained using automated segmentation. STATISTICAL TESTS: One-sample one-sided Wilcoxon signed-rank test was used to establish the clinical quality of images. Agreement between native- and AI-derived lesion volume and lesion count measurements was assessed using intraclass correlation coefficients (ICC). Quantitative accuracy for R2* maps was evaluated using normalized root-mean-square error (NRMSE). RESULTS: AI-generated FLAIR and MPRAGE achieved mean SSIM values of 0.923 ± 0.028 and 0.935 ± 0.022, respectively. Generated R2* maps achieved a mean SSIM of 0.996 ± 0.006 and NRMSE of 0.031 ± 0.020. Physicians-assigned mean clinical quality ratings of 4.2 for GEPCI-FLAIR and 4.5 for GEPCI-MPRAGE exceeded the 4.0 clinical standard on a 1-to-5 scale. Lesion volume and count comparisons from automated segmentation showed strong agreement between AI-generated and ground-truth measurements: R = 0.988 and R = 0.933, ICC = 0.988 and ICC = 0.967, respectively. DATA CONCLUSION: AI-GEPCI generated multiple clinically relevant MRI contrasts from a single GEPCI acquisition with high similarity to corresponding acquired images, supporting high-quality, intrinsically co-registered multi-contrast brain evaluation. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 1.
BACKGROUND: The optimal protocol for clinical liver P-magnetic resonance spectroscopy (MRS) remains unclear. Single-voxel P-MRS using image-selected in vivo spectroscopy (ISIS) employs respiratory-triggering (RT) or free...BACKGROUND: The optimal protocol for clinical liver P-magnetic resonance spectroscopy (MRS) remains unclear. Single-voxel P-MRS using image-selected in vivo spectroscopy (ISIS) employs respiratory-triggering (RT) or free-breathing (FB) acquisition. RT provides robust data but prolongs scan duration; FB allows faster acquisition but may suffer from low signal-to-noise ratio (SNR). Yet, direct comparison using a regulatory-approved coil in a clinical setting has not been reported. PURPOSE: To compare P-MRS data stability and robustness between RT and FB. STUDY TYPE: Prospective. POPULATION: 24 volunteers (19 male/5 female). FIELD STRENGTH/SEQUENCE: 3 T MRI; single-voxel P-MRS using ISIS (free induction decay-based) with approved P coil. METHODS: P-MRS was performed using RT and FB techniques (128 and 192 signal averages, respectively; expected scan duration ~13 min each). Spectra were analyzed using jMRUI. SNR and peak areas for PME, Pi, PDE, α-ATP, and NADPH, normalized using γ-ATP, were compared. PME/PDE and NADPH/(PME + PDE) ratios were also compared. STATISTICAL TEST: Paired t-tests and Bland-Altman analysis were used. A p value < 0.05 was considered significant. RESULTS: Scan duration was significantly longer for RT (15 min 44 s) than FB (12 min 56 s). No significant differences were observed for SNR (p = 0.570), NADPH/(PME + PDE) (p = 0.931), PME/γ-ATP (p = 0.556), Pi/γ-ATP (p = 0.931), α-ATP/γ-ATP (p = 0.332), or NADPH/γ-ATP (p = 0.394). Significant differences were noted for PDE/γ-ATP (RT 1.68 vs. FB 1.35, p = 0.003) and PME/PDE (RT 0.434 vs. FB 0.489, p = 0.046). Bland-Altman analysis showed near-zero fixed biases and no proportional bias, with limits of agreement from -0.53 to 0.62 (PME), -0.30 to 0.30 (Pi), -0.41 to 1.07 (PDE), -0.45 to 0.43 (α-ATP), and -0.80 to 0.90 (NADPH). DATA CONCLUSION: P-MRS of the liver showed equivalent stability and robustness for RT and FB. FB yielded comparable data within a shorter, predictable scan duration. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: 1.
Cine cardiac magnetic resonance imaging (MRI) is the gold standard for cardiac function assessment, offering exceptional spatial and temporal resolution in a non-invasive manner. Recently, there have been attempts to imp...Cine cardiac magnetic resonance imaging (MRI) is the gold standard for cardiac function assessment, offering exceptional spatial and temporal resolution in a non-invasive manner. Recently, there have been attempts to improve signal-to-noise ratio (SNR) and temporal resolution by optimizing pulse sequence parameters such as repetition time (TR), echo time (TE), flip angle (FA), and bandwidth (BW). Although the usual technique is balanced steady-state free precession (bSSFP), its performance is limited due to off-resonance effects, specific absorption rate (SAR) constraints, and susceptibility artifacts, particularly at ≥ 3 T scanners. Due to the lack of breath-hold capacity or arrhythmias in some patients, faster acquisition and motion robustness can be addressed such as wideband bSSFP and real-time imaging through compressed sensing (CS) and artificial intelligence (AI). For patients with severe metal artifacts from cardiac implantable electronic devices (CIEDs), the spoiled gradient recalled-echo (SPGR) sequence is an effective alternative due to its lower sensitivity to susceptibility artifacts. Additionally, innovations in B/B shimming, AI-driven reconstruction, and 7 T MRI promise exceptional image quality but require careful validation and safety management. This review summarizes advances in parameter optimization, artifact mitigation, and sequence selection across magnetic field strengths to enable faster, safer, and more personalized cine cardiac MRI.
Schilder MB, Wallert ED, Mandija S
… +13 more, van der Heide O, Liu H, Fuderer M, Versteeg E, Booij J, de Bie RMA, Beudel M, Berendse HW, van Mierlo T, Blankevoort J, van den Berg CAT, van de Giessen E, Sbrizzi A
BACKGROUND: MR Spin TomogrAphy in Time-domain (MR-STAT) enables accelerated multiparametric relaxometry (T/T). Previous relaxometry studies predominantly compared Parkinson's disease patients with healthy controls (HC)....BACKGROUND: MR Spin TomogrAphy in Time-domain (MR-STAT) enables accelerated multiparametric relaxometry (T/T). Previous relaxometry studies predominantly compared Parkinson's disease patients with healthy controls (HC). The potential of relaxometry to distinguish neurodegenerative from non-neurodegenerative parkinsonism in clinically uncertain parkinsonian syndrome (CUPS) patients is unclear. PURPOSE: To investigate T-/T-differences between neurodegenerative and non-neurodegenerative parkinsonism in CUPS patients. STUDY TYPE: Prospective cross-sectional study. POPULATION: 52 patients with neurodegenerative and 57 patients with non-neurodegenerative parkinsonism, diagnosed via dopamine transporter single photon emission computed tomography (DAT SPECT) and neurologist review, and 10 HC. FIELDSTRENGTH/SEQUENCE: MP-RAGE (magnetization-prepared rapid acquisition with gradient-echoes) and MR-STAT, a 2D Cartesian-encoded gradient-spoiled gradient-echo sequence with time-varying flip-angle preceded by a non-selective inversion pulse, at 3T. ASSESSMENT: Repeatability of T-/T-values was evaluated for cortical gray matter/cerebral white matter/thalamus/putamen/caudate nucleus/globus pallidus (GP) in HC. T-T-values of the parkinsonism groups were compared in the same regions per most/less affected hemisphere (MAH/LAH), determined by the putaminal uptake ratio on DAT SPECT. STATISTICAL TESTS: Regional coefficients of variation (CoV) were computed to assess the repeatability of T-/T-values in HC. T-tests (α = 0.05) were used to compare T-/T-values between parkinsonism groups, and Cohen's D values were computed with bootstrapping to measure effect sizes with 95% confidence intervals (95% CI). RESULTS: CoVs ranged from 0.5% to 1.7% (T) to 1.5% to 2.7% (T). In the MAH, significant T-differences were found in the thalamus (Cohen's D = 0.635, 95% CI = [0.251, 1.016]); GP (Cohen's D = 0.508, 95% CI = [0.129, 0.887]); internal GP (Cohen's D = 0.603, 95% CI = [0.220, 0.983]); external GP (Cohen's D = 0.411, 95% CI = [0.033, 0.787]); and centromedial putamen (Cohen's D = 0.447, 95% CI = [0.069, 0.824]). In the LAH, significant T-differences were found in the thalamus (Cohen's D = 0.476, 95% CI = [0.097, 0.853]); GP (Cohen's D = 0.415, 95% CI = [0.037, 0.791]); anteromedial putamen (Cohen's D = 0.388, 95% CI = [0.011, 0.764]); and external GP (Cohen's D = 0.416, 95% CI = [0.038, 0.792]). T-differences were non-significant. DATA CONCLUSION: MR-STAT showed high repeatability and showed potential to differentiate neurodegenerative from non-neurodegenerative parkinsonism in CUPS patients. EVIDENCE LEVEL: 1. TECHNICAL EFFICACY: 1.