Journal of Magnetic Resonance Imaging最新文献

Background: 3D T1 may assess the superior ophthalmic vein (SOV) congestion, yet its role in the intravenous glucocorticoid (IVGC) therapy remains unclear.

Purpose: To evaluate SOV congestion by 3D T1 in thyroid eye disease (TED) and explore its correlation with IVGC therapeutic response.

Study type: Retrospective.

Subjects: One hundred thirty-three TED patients, classified as 80 IVGC responders (45.7 ± 10.9 years, 32 males) and 53 non-responders (47.6 ± 9.7 years, 23 males); 290 healthy controls (HCs) (47.9 ± 16.4 years, 145 males).

Field strength/sequence: 3 T; 3D T1-weighted spoiled gradient-recalled echo, T2 iterative decomposition of water and fat with echo asymmetric and least-squares estimation, and fat-suppressed (FS) T2 mapping.

Assessment: The SOV diameter (mm), along with the volume ratio, FS T2 relaxation time (T2RT [ms]), and water fraction (WF [%]) of the extraocular muscles (EOMs) and orbital fat (OF) were manually measured.

Statistical tests: Student's t-test, Mann-Whitney U test, one-way analysis of variance, interclass correlation coefficient, and correlation analysis. p < 0.05 defined statistical significance.

Results: TED patients presented significantly larger SOV diameters than HCs (2.21 ± 0.45 vs. 1.72 ± 0.26). Among them, the responsive group had significantly larger baseline SOV diameters (2.26 ± 0.49 vs. 2.15 ± 0.39), along with higher FS T2RT (71.30 ± 14.32 vs. 67.65 ± 13.33) and WF (79.31 ± 13.68 vs. 75.17 ± 14.47) in the EOMs compared to the nonresponsive group. The SOV diameter demonstrated moderate-to-good positive correlations with FS T2RT (r = 0.59) and WF (r = 0.67) in responders. Following IVGC therapy, a significant reduction in SOV diameter was observed exclusively in the responsive group (2.26 ± 0.49 vs. 1.98 ± 0.47).

Data conclusion: Patients exhibiting more severe SOV congestion showed a better response to IVGC therapy, potentially due to an enhanced inflammatory state in the EOMs.

Evidence level: 4.

Technical efficacy: Stage 4.

Background: Venous pulsatile tinnitus (VPT) is associated with transverse-sigmoid sinus (TSS) anomalies, bone dehiscence (BD), and hemodynamic disturbances. 4D Flow MRI enables comprehensive TSS evaluation, but causal relationships among TSS morphology, hemodynamics, and BD in VPT onset and progression remain unquantified. Reliable imaging predictors for VPT progression and BD's mediating role are unestablished.

Purpose: To construct a directed acyclic graph (DAG) testing whether stenosis-induced hemodynamic abnormalities and bone changes predict VPT occurrence and 6-month progression.

Study type: Prospective longitudinal cohort study.

Population: 126 unilateral VPT patients (36 [31-44] years; 73.0% female) and 83 matched non-VPT participants (35 [28-42] years; 71.1% female); all VPT patients completed 6-month symptom follow-up.

Field strength/sequence: 3 T multi-shot turbo field echo 4D Flow MRI and fast field echo phase-contrast MR venography (PC MRV).

Assessment: Three blinded neuroradiologists independently assessed TSS morphology, hemodynamic indices, and petrous BD using PC MRV, 4D Flow MRI, and high-resolution CT multiplanar reconstruction. Interobserver reliability was evaluated with discrepancies resolved by consensus.

Statistical tests: Kolmogorov-Smirnov, Chi-Square, Mann-Whitney U test, FDR-corrected correlation analysis, linear/logistic regression, mediation analysis, and ROC curve analysis.

Significance: p < 0.05.

Results: 74.6% of VPT patients had 6-month progression (increased Tinnitus Handicap Inventory, THI score vs. baseline). Peak flow velocity (38.79 cm/s cut-off) independently predicted 6-month progression (area under the curve, AUC = 0.840; 95% confidence interval, CI: 0.755-0.925). TSS stenosis combined with hemodynamic parameters predicted VPT occurrence (AUC = 0.895, 95% CI: 0.855-0.936). Mediation analysis confirmed BD mediated the effect of wall shear stress on THI. Hierarchical causal pathways among TSS morphology, hemodynamics, BD, and VPT were identified to verify quantifiable DAG.

Data conclusion: TSS stenosis initiates hemodynamic disturbances and bone changes, which collectively drive VPT occurrence and 6-month progression. Integrating these morphological and hemodynamic parameters yields accurate predictive models.

Evidence level: 4.

Technical efficacy: Stage 3.

Background: Coronary microvascular dysfunction (CMD) is a major contributor to cardiovascular complications in diabetes. Although noninvasive techniques such as arterial spin labeling cardiac MRI (ASL-MRI) and transthoracic echocardiography (TTE) are available, their comparative performance for CMD remains unclear.

Purpose: To compare ASL-MRI and TTE for CMD assessment in type 1 and type 2 (T1DM, T2DM) mouse models and relate functional indices to histological microvascular and myocardial remodeling, including early-stage T2DM (8w-T2DM).

Study type: Prospective.

Animal model: Forty 8-week-old male C57BL/6J mice allocated to five groups: control, T1DM, and T2DM (n = 10 per group, imaged 16 weeks postinduction), and early-stage T2DM (8w-T2DM) and age-matched controls (n = 5 per group, imaged 8 weeks post-induction).

Field strength/sequence: Segmented FLASH cine, steady-pulsed labeling ASL, and inversion-recovery segmented FLASH (T1 mapping) sequences at 9.4 T.

Assessment: Rest/stress myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) were derived from ASL data using a model-based approach incorporating native T1 (from segmented FLASH data). Coronary flow velocity (CFV) and reserve (CFVR) were measured by TTE at rest (1.5% isoflurane) and stress (2.5% isoflurane). Histology included assessment of hematoxylin-eosin (myocyte area), Masson (collagen), and IB4 (capillary density).

Statistical tests: Group comparisons used t-tests, Mann-Whitney U tests, and one-/two-way ANOVA with Bonferroni correction; correlations were assessed with Pearson or Spearman coefficients (r). p < 0.05 was considered significant.

Results: 38 animals completed MR and TTE imaging. At 16 weeks, stress diastolic MBF was significantly lower in T1DM (14.67 ± 1.62 mL/g/min) and T2DM (13.42 ± 2.44 mL/g/min) vs. controls (22.19 ± 0.25 mL/g/min), with significantly reduced MPR in T2DM (1.53 ± 0.17 vs. 2.27 ± 0.15). TTE showed significantly reduced CFVR only in T2DM (2.16 ± 0.24 vs. 2.75 ± 0.24). In 8w-T2DM, ASL-MRI detected significantly reduced MPR (1.87 ± 0.16 vs. 2.26 ± 0.13), whereas TTE showed no significant CFVR change (p = 0.900). Capillary density significantly decreased in 16-week and 8-week T2DM. IB4-positive area correlated with CFVR (r = 0.673) and more strongly with MPR (r = 0.810).

Conclusion: ASL-MRI detected CMD in diabetic mice, outperforming TTE in early-stage disease and showing a strong association with microvascular injury.

Evidence level: 1.

Technical efficacy: Stage 2.

Background: Reliable quantification of perivascular spaces (PVS) in the basal ganglia (BG) is of growing interest for understanding the glymphatic system but remains challenging in infants.

Purpose: To develop an automated deep learning method for BG and BG-PVS segmentation in infant brain MRI using an anatomy-informed pseudo-labeling approach.

Study type: Retrospective, multi-cohort technical development, and validation study.

Population: Three cohorts: 150 neonates from the Developing Human Connectome Project (dHCP, 37-44 weeks of gestational age (GA); 76 males, 74 females), 133 infants from the Baby Connectome Project (BCP; ≤ 24 months; 70 males, 63 females) and 70 infants from an in-house dataset (30-41 weeks of GA; 36 males, 34 females). Manual ground-truth labels were generated by a trained researcher (dHCP, n = 150; BCP, n = 8; in-house, n = 10) and validated by a radiologist with 15 years of experience.

Field strength/sequence: Data included 3 T MRI with T1- and T2-weighted sequences: dHCP (inversion recovery turbo spin-echo [IR-TSE] and turbo spin-echo [TSE]), BCP (magnetization-prepared rapid gradient-echo [MPRAGE] and TSE), and in-house (MPRAGE and variable-flip-angle TSE).

Assessment: The proposed approach was compared with alternative automated approaches trained with different labeling strategies. Training/validation/test splits were 100/25/25 (dHCP), 100/25/8 (BCP), and 50/10/10 (in-house).

Statistical tests: Dice similarity coefficient (DSC), recall, positive predictive value, and Hausdorff distance were calculated for BG and BG-PVS quantification. Statistical significance was assessed using Wilcoxon signed-rank tests (p < 0.05), and quantification agreement was evaluated using Pearson's correlation, intraclass correlation coefficient (ICC), and mean absolute error (MAE).

Results: The proposed method improved accuracy (dHCP: BG DSC = 0.91 ± 0.03 and BG-PVS DSC = 0.78 ± 0.09; external datasets with fine-tuning: BG DSC = 0.86-0.89) and high agreement in PVS quantification with reference measurements (r = 0.90-0.99, ICC ≥ 0.96, MAE = 0.10).

Data conclusion: The proposed method seems to enable robust and annotation-efficient BG and BG-PVS segmentation in infants.

Evidence level: 3.

Technical efficacy: 1.

Alzheimer's disease (AD) is one of the most common neurological disorders affecting older adults, with approximately 7.2 million cases only in the United States. This number is projected to increase to 13.8 million in the United States by 2060, leading to increased expenditures for healthcare, long-term care and hospice services. Consequently, great emphasis is placed on prevention and the development of early diagnosis techniques, which can lead to timely treatment and the prevention of the consequences of full-blown disease. In this review, we analyze the potential diagnostic value of biomarkers derived from a multimodal approach based on magnetic resonance spectroscopy, diffusion tensor imaging, and magnetic resonance imaging, capable of detecting metabolic, microstructural, and anatomical changes, respectively, that precede the cognitive and behavioral changes observed in AD by years. The primary aim is to evaluate whether the combined and complementary use of these methods can identify early biomarkers useful for recognizing AD in its early stages, predicting progression from MCI to AD, supporting patient stratification, and monitoring cognitive decline or response to treatment. We identified regions more susceptible to metabolic alterations (PCC and hippocampus) and trajectories of structural brain alterations (atrophy or diffusivity abnormalities). The assessment of such imaging biomarkers may serve as the foundation for future prospective studies aimed at developing differential diagnostic methods, a crucial goal within the broader context of dementias, by adopting standardized multimodal MRI protocols. EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 1.

Intravoxel incoherent motion (IVIM) MRI allows for simultaneous assessment of tissue microcirculation (perfusion) and diffusion of water. In single-center studies, IVIM has shown great potential for diagnosis, treatment outcome prediction, and treatment monitoring for many different diseases and organs. However, heterogeneity in data acquisition protocols, pre-processing pipelines, and post-processing routines yields differences in reported IVIM parameters, which has constrained large-scale deployment of IVIM. Moreover, deploying IVIM protocols and analysis typically requires technical expertise, further challenging wider use, especially for clinicians. In this consensus paper, to accelerate the deployment of IVIM, we provide recommendations and harmonize protocols for brain, breast, kidney, liver, muscle, and pancreas IVIM studies. For this goal we organized multiple questionnaires and held a dedicated workshop. To ensure a level of standardized, reproducible results, without restricting innovation, we suggest a small subset of b-values to always be measured and analyzed separately, and to which more extensive b-value sampling can be added for advanced investigations. We further introduce detailed recommendations on acquisition protocols and analysis pipelines. To increase consistency, repeatability, and reproducibility, we highly recommend that these protocols and pipelines be deployed by scientists and clinicians for IVIM studies. For advanced users who desire different protocols or analysis approaches, we suggest adding results from our suggested protocols and analysis pipeline in the supplemental part of their paper to enable retrospective studies.

Background: Noninvasive detection of glomerular hyperfiltration, a key driver of diabetic nephropathy (DN), is needed for timely intervention (e.g., dapagliflozin), as is early DN identification to guide therapy.

Purpose: To evaluate MR elastography (MRE) for detecting glomerular hyperfiltration and early DN, using glomerular filtration rate (GFR) and pathology as reference standards.

Study type: Animal proof of concept.

Animal model: Ninety-five male Sprague-Dawley rats (80 with high-fat diet and low-dose streptozotocin-induced type 2 diabetes and 15 normal controls).

Field strength/sequence: Briefly, 3.0 T; a multifrequency (100, 150, and 200 Hz) three-dimensional MRE sequence and a multi-b-value (0-800 s/mm²) intravoxel incoherent motion (IVIM) sequence.

Assessment: MRE-derived shear stiffness (SS) and loss modulus (LM) and IVIM-derived true diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) were measured. Glomerular hyperfiltration and DN classes were diagnosed by direct GFR measurement and renal pathology. Ex vivo rheometry validated MRE-derived viscoelastic parameters.

Statistical tests: Linear mixed-effects models; one-way analysis of variance (ANOVA) or Welch's ANOVA; Pearson correlation; intraclass correlation coefficient (ICC); area under the receiver operating characteristic curve (AUC) and DeLong's test. p < 0.05 was considered significant.

Results: Renal SS was significantly higher in hyperfiltration than in controls and early DN (class I-II), distinguishing hyperfiltration from controls (AUC = 0.94) and from early DN (AUC = 0.90). LM was elevated in hyperfiltration but did not decrease significantly in early DN (p > 0.99 vs. hyperfiltration). IVIM parameters showed limited diagnostic utility (AUCs: 0.53-0.72). Dapagliflozin treatment normalized the elevated SS and LM in diabetic rats. Ex vivo rheometry showed significant positive correlations with MRE-derived SS and LM.

Data conclusion: Three-dimensional MRE-derived renal SS is a potential noninvasive biomarker to detect diabetic glomerular hyperfiltration, monitor response to dapagliflozin therapy, and enable early identification of DN.

Evidence level: 1.

Technical efficacy: Stage 2.

Background: Biparametric MRI (bpMRI) was interpreted using Prostate Imaging Reporting and Data System (PI-RADS) version 2.1, a system associated with relatively low specificity. Selective size imaging using filters via diffusion times MRI (SSIFT-MRI) is a novel imaging technique that may improve diagnostic performance.

Purpose: To compare the diagnostic performance of bpMRI versus SSIFT-MRI for diagnosing clinically significant prostate cancer (csPCa).

Study type: Prospective.

Population: Hundred and eighteen men (age: 70 ± 7 years) with suspected csPCa.

Field strength/sequence: Pulsed and oscillating gradient spin-echo sequences at 3 T. BpMRI included three-plane T2-weighted imaging and diffusion-weighted imaging.

Assessment: csPCa status was pathologically determined via ultrasound-guided biopsy or prostatectomy. Three radiologists assessed bpMRI and SSIFT-MRI for identifying csPCa lesions, and we further compared the performance of combining PI-RADS with SSIFT-MRI against that of bpMRI.

Statistical tests: Area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for diagnostic performance; bootstrap resampling for comparing AUC; McNemar's test for comparing sensitivity, specificity, PPV, NPV, and accuracy. A p-value < 0.05 was considered significant.

Results: Per-patient accuracy was significantly higher for SSIFT-MRI (reader 1: 85% vs. 68%; reader 2: 80% vs. 64%; reader 3: 77% vs. 65%). Per-patient specificity (reader 1: 71% vs. 27%; reader 2: 58% vs. 11%; reader 3: 58% vs. 20%) and PPV (reader 1: 84% vs. 67%; reader 2: 78% vs. 64%; reader 3: 77% vs. 65%) were significantly higher for SSIFT-MRI. Combining PI-RADS with SSIFT-MRI yielded significantly higher AUCs and accuracy than bpMRI alone (AUC and accuracy for reader 1: 0.89% and 83%; reader 2: 0.80% and 73%; reader 3: 0.75% and 72%).

Data conclusion: SSIFT-MRI for csPCa had similar or higher diagnostic performance compared with bpMRI. The combination approach provided significantly higher AUC and accuracy than bpMRI.

Evidence level: 1.

Stage of technical efficacy: 2.