Journal of Magnetic Resonance Imaging最新文献

Background: The growing population of patients with active implantable medical devices (AIMDs) presents challenges for MRI access. Safety concerns regarding device malfunction and patient risk, demand standardized management strategies.

Purpose: To evaluate the safety and feasibility of a structured multidisciplinary safety protocol for 1.5T MRI in AIMD carriers.

Study type: Retrospective.

Population: 514 consecutive patients with AIMDs (cardiac implantable electronic devices (CIEDs) (n = 347), auditory implants (n = 85), neurostimulators (n = 61), and drug delivery systems (n = 21)) scheduled for clinical MRI (head (34.3%), spine (19.0%), prostate (10.5%), abdomen/pelvis (9.5%), knee (8.6%), heart (3.8%), and other sites (14.3%)) between 2019 and 2025.

Field strength/sequence: MRI was performed on 1.5T scanners using predefined protocols, with automatic compliance to device-specific SAR limits through the Philips ScanWise Implant software.

Assessment: The safety protocol included device verification, MRI-mode programming, compliance with manufacturer safety conditions, physiologic monitoring, and post-MRI device interrogation. MRI completion rates, exclusion frequencies, and adverse events were recorded, and exclusion proportions were compared across AIMD categories.

Statistical tests: Descriptive statistics.

Results: Of 514 patients, 50 (9.7%) with MR-unsafe, MR-nonconditional, or artifact-prone devices were not scanned: MR-unsafe (n = 23), MR-nonconditional (n = 22), or anticipated severe artifacts (n = 3). Four hundred and sixty-four (90.3%) patients successfully completed diagnostic MRI. Two brain examinations were terminated early due to implant-site pain. No device resets, malfunctions, or significant changes in sensing/pacing thresholds occurred. Internal magnet displacement was observed in three (3.5%) auditory implants, with two requiring surgical repositioning. Exclusion rates varied by device type, ranging from 11% to 14% for CIEDs to 29% for specific neurostimulators.

Data conclusion: A structured, multidisciplinary protocol enables safe MRI in the majority of patients with MR-conditional AIMDs. Standardized pre-MRI screening and management support safe implementation, and improve MRI accessibility for this growing and complex patient population.

Level of evidence: 4:

Technical efficacy stage: 5.

Background: Silicosis is an occupational lung disease characterized by inflammation and fibrosis. As it is irreversible, early identification of high-risk individuals is clinically important, but biomarkers for progression remain lacking.

Purpose: To determine whether ventilation and perfusion defects quantified by phase-resolved functional lung (PREFUL) MRI can predict silicosis progression.

Study type: Prospective.

Subjects: Thirty participants with silicosis (29 males and 1 female) and 30 healthy controls (29 males and 1 female).

Sequence: 2D spoiled gradient echo, 3.0 T.

Assessment: All participants underwent baseline PREFUL MRI, pulmonary function tests (PFTs), and chest CT, with quantitative calculation of ventilation defect percentages (VDP_RVent and VDP_FVL-CM) and perfusion defect percentage (QDP). Silicosis was followed for 1 year with assessments including forced vital capacity percent predicted (FVC% predicted), diffusing capacity of the lungs for carbon monoxide percent predicted (DL_co% predicted), symptoms, and CT. Disease progression was defined by any two of: (a) CT evidence of progression, (b) worsening symptoms, or (c) ≥ 10% decline in FVC% predicted or ≥ 15% decline in DLco% predicted.

Statistical tests: Spearman correlation coefficients were used to evaluate the correlation between ventilation/perfusion metrics and PFT parameters. Receiver operating characteristic (ROC) curves were used to assess the ability of PREFUL MRI parameters to classify disease progression, reporting the area under the curve (AUC), sensitivity, and specificity. Significance was set at p < 0.05.

Results: Eight patients progressed and 22 remained stable. Baseline VDP_RVent, VDP_FVL-CM, and QDP were significantly higher in progressors (36%, 34%, 40%) than in non-progressors (22%, 15%, 22%). QDP showed strong predictive performance with AUC of 0.72 (95% CI: 0.51-0.93) for radiological progression, 0.90 (95% CI: 0.79-1.00) for PFTs decline, and 0.97 (95% CI: 0.92-1.00) for global progression.

Data conclusion: Increased ventilation and perfusion defects on PREFUL MRI are associated with silicosis progression.

Evidence level: 2.

Technical efficacy: Stage 2.

Trial registration: NCT06431555.

Background: Isocitrate dehydrogenase (IDH) mutation status is an important biomarker for the diagnosis and management of nonenhancing gliomas, underscoring the need for noninvasive preoperative classification.

Purpose: To compare the value of habitat-based and whole-tumor strategies in classifying IDH mutation status in nonenhancing gliomas via transfer learning on structural magnetic resonance imaging and subtraction images.

Study type: Retrospective.

Population: Two-hundred and eighty-four patients with nonenhancing gliomas, divided into a training set (n = 198; 44 ± 12 years; 83 females) and a testing set (n = 86; 46 ± 11 years; 35 females).

Field strength/sequence: 3T, fluid-attenuated inversion recovery (FLAIR), fast spin-echo (FSE) T2-weighted imaging (T2WI), FSE T1-weighted imaging (T1WI), contrast-enhanced FSE T1-weighted imaging (T1CE).

Assessment: Based on FLAIR, T2WI, T1WI, T1CE, and subtraction images, two regions of interest input strategies were applied to construct transfer learning models, including whole-tumor strategy and habitat-based strategy. Model performance was evaluated using the area under curves (AUC) and accuracy (ACC). Finally, the optimal model was combined with clinical variables to develop integrative models.

Statistical tests: Continuous variables were analyzed by Student's t test or Wilcoxon rank-sum test; categorical variables by χ² test or Fisher's exact test. Two-sided p < 0.05 was statistically significant.

Results: In the whole-tumor strategy, the subtraction model demonstrated significantly superior performance, achieving training and testing set AUC/ACC of 0.850/0.813 and 0.890/0.884. The habitat-based strategy significantly outperformed the whole-tumor strategy, with the T2WI model demonstrating optimal efficacy (training set, AUC/ACC = 0.898/0.899; testing set, AUC/ACC = 0.870/0.849). The integrative model (habitat-based T2WI + Age + Location) achieved the highest classification performance, with AUCs of 0.923 and 0.947 in the training and testing sets, respectively.

Data conclusion: The habitat-based strategy outperforms the whole-tumor approach, with the habitat-based T2WI model achieving optimal classification performance. Integrating age and tumor location into this model can further boost its classification capability.

Level of evidence: 3:

Technical efficacy: Stage 2.

Background: Cerebrospinal fluid (CSF) serves as a medium for nutrient delivery and waste clearance. The T1 relaxation rate, R1, can be used to measure the concentration of intrinsic solutes and extrinsic contrast agents.

Purpose: To implement a method for R1 mapping and segmentation of CSF and to use this method to explore how R1 of CSF relates to protein content and gadobutrol after intrathecal administration.

Study type: Prospective cohort study, complemented by phantom analysis.

Population: Ten healthy control subjects (mean age 65.5 ± 4.4 years, range 57-72 years; five males and five females) and protein- and gadobutrol-gradient phantom.

Field strength/sequence: 3 T Philips Ingenia scanner; 3D T2W mixed inversion recovery spin-echo (T2W-mixed IRSE) sequence and 3D T1W turbo field echo (3D T1W-TFE).

Assessment: R1 maps were calculated by combining IR and SE data. An automated segmentation method derived from FreeSurfer employed SE data for CSF segmentation and T1W-TFE for anatomical reference. CSF was collected by lumbar puncture for protein measurements, and 0.25 mmol gadobutrol was injected intrathecally. Post-contrast assessments were performed at 3, 24, 48, and 72 h.

Statistical tests: One-way ANOVA, followed by a post hoc Tukey HSD test, and simple and multiple linear regression analysis; significance level of 0.05.

Results: R1 of ventricular CSF 0.216 ± 0.001 s^-1 was significantly lower than that surrounding the cerebellum 0.225 ± 0.001 and cerebrum 0.228 ± 0.002 and correlated with lumbar protein concentration (R² = 0.56). Peak gadobutrol concentrations were 101 ± 84 μM in ventricles, 185 ± 89 μM in cerebellar SAS and 166 ± 91 μM in cerebral SAS. Corresponding concentrations were 6 ± 4, 17 ± 8, and 37 ± 18 μM at 72 h.

Data conclusion: Intrinsic R1 of CSF in the subarachnoid space correlated with protein content. Intracranial CSF enrichment after intrathecal administration of gadobutrol showed a large variation among healthy volunteers.

Evidence level: 2.

Technical efficacy: 3.