Journal of Magnetic Resonance Imaging最新文献

Background: Quantitative magnetic resonance imaging metrics iron-corrected T1 (cT1) and liver fat from proton density fat-fraction (PDFF) are both commonly used as noninvasive biomarkers for metabolic dysfunction-associated steatohepatitis (MASH); however, their repeatability in this population has rarely been characterized.

Purpose: To quantify the variability of cT1 and liver fat fraction from PDFF in patients with biopsy-confirmed metabolic dysfunction-associated steatotic liver disease (MASLD) and MASH.

Study type: Prospective, single center.

Population: Twenty-one participants (female = 11, mean age 53 ± 24 years) with biopsy-confirmed MASLD, including 6 with MASH and fibrosis ≥2.

Field strength/sequence: 3 T; T1 and T2* mapping for the generation of cT1 (shMOLLI: CardioMaps and 2D MDE, T1map-FIESTA and LMS MOST: StarMap, 2D Multi-Echo FSPGR) and magnitude-only PDFF sequence for liver fat quantification (LMS IDEAL: StarMap, 2D Multi-Echo FSPGR).

Assessment: T1 mapping and PDFF scans were performed twice on the same day for all participants (N = 21), with an additional scan 2-4 weeks later for MASH patients with fibrosis ≥2 (N = 6). Whole liver segmentation masks were generated semi-automatically and average pixel counts within these masks were used for the calculation of cT1 and liver fat fraction.

Statistical tests: Bland-Altman analysis for repeatability coefficient (RC) and 95% limits of agreement (LOA) and intraclass correlation coefficient (ICC).

Results: Same-day RC was 32.1 msec (95% LOA: -36.6 to 24.2 msec) for cT1 and 0.6% (95% LOA: -0.5% to 0.7%) for liver fat fraction; the ICCs were 0.98 (0.96-0.99) and 1.0, respectively. Short-term RC was 65.2 msec (95% LOA: -63.8 to 76.5 msec) for cT1 and 2.6% (95% LOA: -2.8% to 3.1%) for liver fat fraction.

Data conclusion: In participants with MASLD and MASH, cT1 and liver fat fraction measurements show excellent test-retest repeatability, supporting their use in monitoring MASLD and MASH.

Level of evidence: 2 TECHNICAL EFFICACY: Stage 2.

Background: Primary open-angle glaucoma (POAG), a leading cause of irreversible blindness, is associated with neurodegeneration in the visual pathway, but the underlying pathophysiology remains incompletely resolved.

Purpose: To characterize macro- and microstructural white matter abnormalities in optic tract (OT) and optic radiation (OR) of POAG.

Study type: Prospective.

Populations: A total of 34 POAG patients (21 males, 13 females) and 25 healthy controls (HCs) (16 males, nine females).

Field strength/sequence: 3 T; multiband spin-echo echo planar diffusion spectrum imaging (DSI).

Assessment: We compared multiple morphology metrics, including volume, area, length, and shape metrics, as well as diffusion metrics such as diffusion tensor imaging (fractional anisotropy [FA], mean diffusivity, radial diffusivity, and axial diffusivity), mean apparent propagator (mean squared displacement, q-space inverse variance, return-to-origin probability, return-to-axis probabilities [RTAP] and return-to-plane probabilities, non-Gaussianity, perpendicular non-Gaussianity, parallel non-Gaussianity), and neurite orientation dispersion and density imaging (intracellular volume fraction, orientation dispersion index [ODI], and isotropic volume fraction of the OT and OR).

Statistical tests: Statistical comparisons and classifications employed linear mixed model and logistic regression. Diagnostic performance was assessed using area under the receiver operating characteristic curve (AUC). P-value <0.05 was statistically significant.

Results: Morphology analysis in POAG revealed a lower span in the OR (29.43 ± 2.30 vs. 30.59 ± 2.01, 3.8%) and OT (19.73 ± 2.21 vs. 20.68 ± 1.37, 4.6%), and a higher curl (3.03 ± 0.22 vs. 2.90 ± 0.16, 4.5%) in OT. Diffusion metrics revealed lower mean FA (OR: 0.328 ± 0.03 vs. 0.340 ± 0.018, 3.5%; OT: 0.255 ± 0.022 vs. 0.268 ± 0.018, 4.9%) and lower mean RTAP (OR: 5.919 ± 0.529 vs. 6.216 ± 0.489, 4.8%; OT: 4.089 ± 0.402 vs. 4.280 ± 0.353, 4.5%), with higher mean ODI in the OT (0.448 ± 0.029 vs. 0.433 ± 0.025, 3.5%). Combined models, incorporating these MRI metrics, effectively discriminated POAG from HCs, achieving AUCs of 0.84 for OR and 0.83 for OT.

Data conclusions: DSI-derived morphology and diffusion metrics demonstrated macro- and micro abnormalities in the visual pathway, providing insights into POAG-related neurodegeneration.

Level of evidence: 2 TECHNICAL EFFICACY: Stage 3.

Background: Birth asphyxia (BA) and germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH) are common clinical events in preterm neonates. However, their effects on the glymphatic system (GS) development in preterm neonates remain arcane.

Purpose: To evaluate the developmental trajectory of the GS, and to investigate the effects of BA and GMH-IVH on GS function in preterm neonates.

Study type: Prospective.

Population: Two independent datasets, prospectively acquired internal dataset (including 99 preterm neonates, 40 female, mean [standard deviation] gestational age (GA) at birth, 29.95 [2.63] weeks) and the developing Human Connectome Project (dHCP) dataset (including 81 preterm neonates, 29 female, median [interquartile range] GA at birth, 32.71 [4.28] weeks).

Field strength/sequence: 3.0 T MRI and diffusion-weighted spin-echo planar imaging sequence.

Assessment: The diffusion-weighted images were preprocessed in volumetric space using the FMRIB Software Library and diffusion along the perivascular space (DTI-ALPS) index was accessed to evaluate GS function.

Statistical tests: Two sample t tests, one-way analysis of variance followed by least-significant difference (LSD) post hoc analysis, chi-squared tests, and Pearson's correlation analysis. Significance level: P < 0.05.

Results: In prospectively acquired internal dataset, preterm neonates with BA exhibited a significant lower DTI-ALPS index than those without BA (0.98 ± 0.08 vs. 1.08 ± 0.07, T = -5.89); however, GMH-IVH did not exert significant influences on the DTI-ALPS index (P = 0.83 and 0.27). The DTI-ALPS index increased significantly at postmenstrual age ranging from 25 to 34 weeks (r = 0.38) and then plateaued after 34 weeks (P = 0.35), which we also observed in the dHCP dataset.

Data conclusion: BA rather than GMH-IVH serves as the major influencing factor in the development of GS in preterm neonates. Moreover, as GS development follows a nonlinear trajectory, we recommend close monitoring of GS development in preterm neonates with a GA less than 34 weeks.

Level of evidence: 2 TECHNICAL EFFICACY: Stage 2.

In patients with acute myocardial infarction (AMI), traditional clinical endpoints used to assess drug efficacy and prognosis include infarct size (IS), incidence of heart failure, and mortality rates. Although these metrics are commonly employed to evaluate outcomes in AMI patients, their utility is limited in small-scale studies. The introduction of the myocardial salvage index (MSI) reduces variability in assessments across multiple dimensions, thereby enhancing the sensitivity of outcome measures and reducing the required sample size. Moreover, MSI is increasingly utilized to evaluate drug efficacy, prognosis, and risk stratification in AMI patients. Although a variety of methodologies for measuring the MSI are currently available, the incorporation of these methods as clinical endpoints remains limited. In the clinical application of cardioprotective strategies, it is recommended that MSI be evaluated using late gadolinium enhancement measured along the endocardial surface length combined with IS in cardiac magnetic resonance. In dynamic single-photon emission computed tomography, an assessment of MSI using methods based on abnormalities in myocardial wall thickening combined with perfusion anomalies is advocated. This review comprehensively outlines the principles, advantages, and limitations of different MSI assessment methods and discusses the prospects and challenges of MSI in cardiac protective therapies. Additionally, we summarize recommended strategies for employing MSI as a clinical surrogate endpoint in various clinical scenarios, providing direction for future clinical practice and research. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 4.

Background: Progressive supranuclear palsy (PSP) can cause structural and functional brain reconstruction. There is a lack of knowledge about the consistency between structural-functional (S-F) connection networks in PSP, despite growing evidence of anomalies in various single brain network parameters.

Purpose: To study the changes in the structural and functional networks of PSP, network's topological properties including degree, and the consistency of S-F coupling. The relationship with clinical scales was examined including the assessment of PSP severity, and so on.

Study type: Retrospective.

Subjects: A total of 51 PSP patients (70.04 ± 7.46, 25 females) and 101 healthy controls (64.58 ± 8.84, 58 females).

Field strength/sequence: 3-T, resting-state functional MRI, diffusion tensor imaging, and T1-weighted images.

Assessment: A graph-theoretic approach was used to evaluate structural and functional network topology metrics. We used the S-F coupling changes to explore the consistency of structural and functional networks.

Statistical tests: Independent samples t tests were employed for continuous variables, χ² tests were used for categorical variables. For network analysis, two-sample t tests was used and implied an false discovery rate (FDR) correction. Pearson correlation analysis was used to explore the correlations. A P-value <0.05 was considered statistically significant.

Results: PSP showed variations within and between modules. Specifically, PSP had decreased network properties changes (t = -2.0136; t = 2.5409; t = -2.5338; t = -2.4296; t = -2.5338; t = 2.8079). PSP showed a lower coupling in the thalamus and left putamen and a higher coupling in the visual, somatomotor, dorsal attention, and ventral attention network. S-F coupling was related to the number of network connections (r = 0.32, r = 0.22) and information transmission efficiency (r = 0.55, r = 0.28). S-F coupling was related to basic academic ability (r = 0.39) and disinhibition (r = 0.49).

Data conclusion: PSP may show abnormal S-F coupling and intramodular and intermodular connectome in the structural and functional networks.

Level of evidence: 3 TECHNICAL EFFICACY: Stage 3.