Journal of Magnetic Resonance Imaging最新文献

Background: Contrast administration may contribute to patient anxiety and safety concerns during magnetic resonance imaging (MRI), yet patient experiences specific to contrast-enhanced MRI (CE-MRI) examination remain underexplored.

Purpose: To explore patients' experiences during CE-MRI examination, focusing on anxiety levels and safety perceptions.

Study type: Questionnaire-based study with follow-up patient interviews.

Subjects: Two hundred and three adult patients undergoing CE-MRI in public hospitals; 28 participated in follow up interviews.

Field strength/sequence: 1.5 Tesla/standardized MRI scanning protocols across multiple body regions comprised 6-17 sequences per examination, with total table times ranging from 30 to 50 min, depending on the anatomical region examined.

Assessment: A structured questionnaire consisted of 31 items covering demographic characteristics, scan related information, experience with the CE-MRI examination, including information received, and anxiety assessment before, during, and after the CE-MRI examination using a four-point Likert scale. Following the CE-MRI examination, 28 patients from this original cohort participated in semi-structured interviews to explore their anxiety levels and perceptions of safety during the examination.

Statistical test: Quantitative data were analyzed using SPSS, and a p value < 0.05 was considered significant. While qualitative data were analyzed thematically using NVivo software.

Results: Forty-six percent of patients reported increased anxiety during contrast administration, and 26.1% rated the information provided about the examination unclear. It was found that 35% felt the examination did not meet their expectations based on the information given. Anxiety was more prevalent among females (Mean = 1.71), younger patients (Mean = 2.04), and those with higher education levels (Mean = 1.96). Qualitative findings identified key anxiety triggers, including sensory discomfort, fear of unknown outcomes, and poor timing or poor clarity of information. Empathetic communication and clarity were perceived as essential anxiety-reducing factors. Notably, anxiety levels significantly decreased after the examination (χ² = 24.955).

Data conclusion: Anxiety levels were influenced by sex, age, education level, the provided information, and the quality of communication.

Evidence level: 4.

Stage of technology efficacy: Stage 3 (Diagnostic Thinking).

Background: One manifestation of multiple sclerosis (MS) is abnormal iron-related susceptibility changes in deep gray matter (DGM), contributing to oxidative stress and neurodegeneration. Intermittent fasting (IF) is a metabolic intervention that may influence inflammatory and iron-related pathways.

Purpose: To compare susceptibility-derived phase values in DGM between fasting and non-fasting periods in patients with MS.

Study type: Retrospective observational cohort study.

Population: 36 patients with MS were studied: a fasting group (n = 20; mean age 33.1 ± 9.6 years; 14 males), a non-fasting control group (n = 14; mean age 34.9 ± 10.8 years; 10 males), and two cases with additional measurements.

Field strength/sequence: 1.5 T; Echo Planar Susceptibility-Weighted Imaging (EPI-SWI).

Assessment: Paramagnetic mean phase values (pMPVs) were measured in nine bilateral DGM regions at 2 time points separated by a 1-year interval.

Statistical tests: Paired and independent t-tests were used to analyze phase value changes; a p-value of less than 0.05 was considered statistically significant.

Results: Inter-rater reliability was high (ICC = 0.91). The fasting group had lower pMPVs at the second time compared to the first (48.91 ± 10.45 vs. 38.38 ± 11.23; mean difference -10.53; 95% CI: -13.28 to -7.78), with consistent reductions across all subregions. The non-fasting group showed the opposite pattern (45.42 ± 19.98 vs. 52.99 ± 21.05; 95% CI: 4.71 to 10.43), while bilateral thalamic values remained stable (left p = 0.104; right p = 0.938). Serial case studies are associated with temporal patterns in pMPVs during fasting and non-fasting intervals.

Data conclusion: Measurements during fasting periods were associated with lower pMPVs in DGM in multiple sclerosis compared to non-fasting periods.

Level of evidence: 3:

Technical efficacy: Stage 3.

Background: 4D flow MRI-derived parameters such as wall shear stress (WSS) may improve abdominal aortic aneurysm (AAA) progression prediction. Validation of this biomarker is needed, but longitudinal data are lacking.

Purpose: Investigate longitudinal WSS changes and associations with AAA morphology.

Study type: Prospective.

Subjects: Fifteen patients (mean age 68.7 ± 8.9 years; 1 female) with AAA > 30 mm in diameter.

Field strength/sequence: 3.0 T, 4D flow MRI, 3D cine balanced steady state free precession, and Dixon.

Assessment: Patients had baseline and follow-up MRI studies, separated by 6 months. A previously developed automated post-processing 4D flow MRI software was utilized to assess WSS, total lumen, and thrombus volumes. Maximum diameter in the anteroposterior (AP) and left-right (LR) directions was measured by three radiologists (with 13, 12, and 3 years of experience) based on the Dixon MRI at both time-points. Statistically significant growth was defined as an increase exceeding twice the standard error of the measurement. Baseline and follow-up 3D WSS maps were visually compared to identify potential temporal differences.

Statistical tests: The Wilcoxon signed-rank test was applied to evaluate differences in diameter, volume, and WSS measurements between baseline and follow-up. Spearman's rank correlation coefficients were calculated to assess correlations between (half-year change in) WSS values and AAA diameter and volumes.

Results: Maximum AAA diameter increased significantly from baseline to follow-up. Also, a significant difference was observed in maximum peak WSS between baseline and follow-up. A significant inverse correlation was observed between the change in minimum peak WSS and AAA lumen volume over follow-up. Visual assessment of WSS maps may improve 4D flow-based AAA surveillance by identifying localized changes.

Data conclusion: Maximum AAA diameter increased over the study period. Changes in WSS were inversely associated with changes in AAA lumen volume over follow-up but not with maximum AAA diameter. Longer follow-up is needed to assess the potential of WSS as a biomarker for AAA progression.

Evidence level: Level 2.

Technical efficacy: Level 3.

Background: Intratumoral fibrosis influences treatment efficacy and prognosis of rectal cancer (RC). The roles of MR elastography (MRE) and Virtual MRE (VMRE) remain unclear in assessing it in RC.

Purpose: To evaluate MRE for assessing intratumoral fibrosis in RC, identify optimal b-values for VMRE, and compare their diagnostic performance.

Study type: Prospective cohort.

Population: A total of 71 participants with pathologically confirmed RC (47 men; mean age, 62 ± 10 years).

Field strength/sequences: 3T, T2-weighted turbo-spin echo, contrast-enhanced T1-weighted gradient-recalled echo, Intravoxel incoherent motion (IVIM) (b = 0, 100, 200, 1000, 1500 s/mm²), and spin-echo MRE.

Assessment: All participants were divided at a 7:3 ratio: subgroup 1 (N = 49) determined the optimal b-value combination and established the empirical relationship between shifted apparent diffusion coefficient (sADC) and VMRE (Vc, Vφ) based on IVIM, with MRE (c, φ) as reference; subgroup 2 (N = 22) validated this relationship. MRE and VMRE evaluated intratumoral fibrosis in 43 surgically diagnosed participants.

Statistical tests: Receiver operating characteristic (ROC), Pearson correlation, DeLong test. Bonferroni-adjusted p < 0.05 indicated statistical significance.

Results: The optimal combination of b-values was 0 and 1500 s/mm² (r_c = -0.808, r_φ = -0.644) for VMRE in subgroup 1. In 43 surgically diagnosed participants, area under curves (AUCs) of c and φ for assessing intratumoral fibrosis were 0.779 and 0.684, respectively (Adjusted p = 0.828). AUCs of Vc and Vφ converted from sADC_0-1500 values were 0.792 and 0.784, respectively (Adjusted p > 0.999). No significant differences in AUCs were observed among all parameters (Adjusted p: 0.384 to > 0.999). Sensitivity and specificity ranges of MRE and VMRE were 85.7%-90.5% and 54.5%-68.2%, respectively.

Data conclusions: MRE was used to evaluate intratumoral fibrosis in RC. The optimal b-values combination for VMRE in RC was 0 s/mm² and 1500 s/mm². No significant difference was observed for assessing intratumoral fibrosis between MRE and VMRE.

Evidence level: 2.

Technical efficacy: Stage 2.

MISL maps (slice 5–12) at (a) –20 ppm and (c) –10 ppm were collected from the brain of a 41-year-old female HC subject and a 47-year-old female MS patient. Comparison of MISL signals between HC (n = 15) and MS (n = 12) groups at (b) –20 ppm and (d) –10 ppm. An unpaired Student's t-test was used. HC: healthy control; MISL: magnetization transfer indirect spin labeling; MS: multiple sclerosis. By Wang et al. (759–771).

MISL maps (slice 5–12) at (a) –20 ppm and (c) –10 ppm were collected from the brain of a 41-year-old female HC subject and a 47-year-old female MS patient. Comparison of MISL signals between HC (n = 15) and MS (n = 12) groups at (b) –20 ppm and (d) –10 ppm. An unpaired Student's t-test was used. HC: healthy control; MISL: magnetization transfer indirect spin labeling; MS: multiple sclerosis. By Wang et al. (759–771).

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.