Journal of Magnetic Resonance Imaging最新文献

Background: Noninvasive detection of chronic pancreatitis (CP) is important for proper treatment and prevention of severe pain and pancreatic insufficiency.

Purpose: To evaluate if T₁ρ MRF is significantly different in healthy volunteers and patients with CP.

Study type: Prospective.

Population: Seventeen healthy volunteers (9 male, mean age: 38.0 ± 6.7 years) and 20 patients (12 male, mean age: 53.6 ± 6.4 years) who were clinically diagnosed with CP.

Field strength/sequence: 3 T, T₁ρ MRF acquired during breath-hold (BH-MRF) and free breathing (FB-MRF), conventional T₁/T₂ mapping sequences.

Assessment: Mean T₁/T₂/T₁ρ values in the whole pancreas were compared between diagnosed CP patients and controls. The Cambridge classification (CC) score was used to divide patients into mild-moderate (CC = 1-3) and severe (CC = 4) CP subgroups. T₁, T₂, and T₁ρ relaxation maps were generated from both breath-hold (BH) and free-breathing (FB) MRF data.

Statistical tests: Mixed effects models were calculated for healthy control versus CP, and between mild-moderate and severe CP. Receiver operator characteristic (ROC) curves were analyzed and areas under the curves (AUCs) were calculated. A p-value < 0.05 was considered significant and multiple comparison corrections were applied.

Results: BH-MRF T₁/T₂/T₁ρ values were significantly higher in the CP group (1327.3, 48.6, 49.1 ms) compared to healthy controls (821.6, 41.6, 39.5 ms) with AUCs of 0.994, 0.873, and 0.862, respectively. The MRF BH T₁/T₂/T₁ρ values of mild-moderate CP (N = 7) and severe CP (N = 13) patients were also significantly higher compared to healthy controls. T₁ was significantly higher in severe CP compared to mild-moderate CP (1497 and 1012.1 ms, respectively) with AUC = 0.945. FB MRF T₁ relaxation times demonstrated good correlation with BH values (0.981), while T₂ and T₁ρ had moderate correlations (0.507 and 0.697, respectively).

Data conclusions: T₁, T₂, and T₁ρ relaxation times have potential for noninvasively assessing CP.

Evidence level: 2.

Technical efficacy: Stage 2.

Background: ³¹P magnetic resonance spectroscopy (³¹P-MRS) allows non-invasive assessment of mitochondrial function by quantifying metabolites of energy and phospholipid metabolism, but the association between these metabolic alterations and motor laterality in Parkinson's disease (PD) remains unknown.

Purpose: To investigate the association between mitochondrial dysfunction and motor symptom lateralization in PD using ³¹P-MRS.

Study type: Retrospective.

Population: 34 PD patients with left-sided predominance (LPD; 20 M/14 F), 35 PD patients with right-sided predominance (RPD; 16 M/19 F), and 43 healthy controls (HCs; 20 M/23 F).

Fieldstrength/sequence: 3T; 3D T1-weighted gradient-echo and 2D FID-based chemical shift imaging sequences.

Assessment: ³¹P-MRS spectra from bilateral putamen, frontal, and temporoparietal cortices were quantified for adenosine triphosphate (ATP), phosphocreatine (PCr), inorganic phosphate (Pi), phosphomonoesters (PME), and phosphodiesters (PDE). Metabolite levels were corrected for cerebrospinal fluid (CSF) partial volume effects. Metabolic ratios and laterality indices (LIs) were calculated and correlated with motor symptom LIs.

Statistical tests: General linear models, spearman's rank correlation, and receiver operating characteristic (ROC) analysis. p < 0.05 was considered statistically significant.

Results: RPD patients exhibited significantly elevated ATP (0.181 ± 0.005) and reduced PCr/ATP (0.979 ± 0.033) in the left putamen compared to HCs (0.164 ± 0.004; 1.098 ± 0.030); they also showed a significantly lower frontal PDE LI (-0.069 ± 0.022), higher temporoparietal Pi LI (0.086 ± 0.039), and reduced PCr/Pi LI (-0.106 ± 0.041) relative to LPD patients (-0.019 ± 0.022; -0.075 ± 0.040; 0.047 ± 0.042). In the temporoparietal cortex, the LIs of PCr/Pi (r = 0.260), PME/PDE (r = 0.323), and Pi (r = -0.315) were significantly correlated with the LIs of UPDRS-III scores. The Pi LI in the temporoparietal cortex showed a promising ability to distinguish LPD from RPD patients (AUC = 0.709).

Data conclusion: Asymmetrical mitochondrial dysfunction, detected by ³¹P-MRS, correlates with motor symptom laterality in PD. These metabolic asymmetries may serve as the underlying basis for symptom lateralization.

Evidence level: 3.

Technical efficacy: Stage 1.

Background: Current reference standards for measuring gastric emptying and motility are not considered optimal due to the time required, ionizing radiation, invasiveness, and spatial resolution.

Purpose: To assess gastric motility using novel real-time dynamic magnetic resonance imaging in combination with static measurements for gastric emptying and training of an automated deep-learning-based segmentation pipeline.

Study type: Prospective.

Participants: The study included 36 healthy volunteers (20 female, mean 24 ± 3 years) and three patients with diagnosed Crohn's disease.

Field strength/sequences: Participants ingested water to assess fasting motility and pineapple juice for the postprandial state. 3 T, 3D spoiled gradient echo (GRE) sequence and real-time spoiled GRE.

Assessment: Gastric emptying was measured by using the gastric volume, while motility was analyzed by tracking changes in the antrum's cross-sectional area and applying Fast Fourier Transformation. Segmentations were performed using a trained semantic segmentation model.

Statistical tests: Linear Mixed Model with continuous dependent variables and fixed effects. Models included a random intercept for participants. Statistical significance was defined as p = 0.05.

Results: The method enabled volumetric analysis of gastric content from 3D breath-hold static acquisition and time-resolved quantification of peristaltic parameters from real-time FLASH2 imaging at high temporal resolution (here 6.24 fps). Water emptied rapidly and exponentially (t_1/2 = 14.77 ± 10.55 min), while juice showed slower emptying (t_1/2 = 64.24 ± 11.87 min). Contraction frequencies (fasted: 2.76 ± 0.43 cpm, fed: 2.89 ± 0.43 cpm) and velocities (fasted: 1.67 ± 0.38 mm/s, fed: 1.72 ± 0.37 mm/s) were within physiological ranges, with fasting conditions characterized by stronger occlusion compared to the fed. Measurements taken from three patients proved that the workflow could be used in a clinical context.

Data conclusion: Real-time MRI with AI-based analysis enabled quantitative assessment of gastric emptying and motility, revealing physiological peristaltic parameters and state-dependent differences in occlusion.

Evidence level: 2.

Technical efficacy: Stage 1.

Background: Excessive daytime sleepiness (EDS) substantially impairs health-related quality of life and cognitive function in obstructive sleep apnea (OSA) patients. However, the underlying neuropathological mechanisms remain poorly understood.

Purpose: To investigate the associations between EDS, cognitive deficits, and brain alterations in OSA patients.

Study type: Prospective.

Population: One hundred two OSA patients (16 female, median age (IQR) 33.00 [28.00-41.00]) and 86 healthy controls (HCs) (16 female, median age (IQR) 33.00 [25.00-50.25]) were prospectively recruited.

Field strength/sequence: 3 T, 3D spoiled gradient-echo, diffusion-weighted spin-echo, blood oxygen level-dependent gradient-echo planar.

Assessment: The Epworth Sleepiness Scale, multiparameter MRI, and a series of neuropsychological tests (the number connection tests A and B, digit symbol test, line tracing test, serial dotting test, and Stroop Color/Word test) were performed to evaluate EDS, brain alterations, and cognitive performances.

Statistical tests: Mann-Whitney U test, independent samples t-test, chi-square test, Spearman's correlation, and mediation analyses were used. Significance level: p < 0.05.

Result: OSA patients exhibited statistically poorer cognitive performance (effect size = 0.23-0.37), lower diffusion tensor imaging along the perivascular space (DTI-ALPS) index (effect size = 0.25), and abnormal network topology (effect size = -0.80 to 0.57) compared with HCs. EDS significantly correlated with poorer cognitive performance (r = -0.173 to 0.258), lower DTI-ALPS index (r = -0.199), and abnormal network topology (r = -0.364 to 0.279) in all participants. Furthermore, aberrant degree centrality and nodal efficiency in the bilateral middle frontal gyrus (MFG) and left inferior parietal lobule (IPL) may mediate the relationship between EDS and cognitive deficits (indirect effect = -0.13 to 0.36).

Data conclusion: These results demonstrate that cognition, DTI-ALPS index, and network topology were all compromised in OSA. Furthermore, abnormal network topology in the bilateral MFG and left IPL may mediate the relationship between EDS and cognitive deficits.

Evidence level: Level 2.

Technical efficacy: Stage 2.