Journal of Magnetic Resonance Imaging最新文献

Background: 10%-30% of patients with lung adenocarcinoma (LUAD) and leptomeningeal metastasis (LM) respond poorly to conventional and targeted therapy. The relationship between genetic subtypes and both MRI features and survival outcomes remains poorly understood in this patient population.

Purpose: To explore the genetic phenotypes among LUAD-LM patients who respond poorly to conventional and targeted therapy, and to compare the MRI characteristics and survival outcomes among these genetic phenotypes: STUDY TYPE: Retrospective.

Population: 110 LUAD-LM patients (LU confirmed by histology, LM by cytology) treated with intrathecal chemotherapy, comprising 43 with epidermal growth factor receptor exon 21 L858R mutations (EGFR 21), 29 with EGFR exon 19 deletions (EGFR 19), and 38 with Non-Classic and Other Mutations (NCOM).

Field strength/sequence: 3.0T; axial T₁- and T₂-weighted turbo spin echo (TSE), fluid-attenuated inversion recovery (FLAIR), diffusion-weighted echo-planar imaging (DWI), and post-contrast 3D T₁-weighted gradient-echo sequences (3D T1WI).

Assessment: MRI morphologic features (including LM presence, presentation subtype, and lesion distribution) were independently reviewed by three radiologists (Y. J., W. S., and M. Y., with 5, 5, and 15 years of experience, respectively), following standardized criteria. Intracranial progression-free survival (iPFS) and overall survival (OS) were analyzed from the date of LM diagnosis based on clinical follow-up.

Statistical tests: Chi-square or Fisher's exact tests for imaging features; Kaplan-Meier method with log-rank tests for survival analysis; Cox proportional hazards regression for multivariable analysis. A two-sided p < 0.05 was considered significant.

Results: MRI-negative LM was significantly more frequent in EGFR 19 (65.5%). However, these patients showed no survival advantage (iPFS: p = 0.10, OS: p = 0.64) over other groups. Among MRI-positive LM patients, EGFR 21 affected significantly fewer lobes (< 4 lobes: 85.7%) compared to NCOM (< 4 lobes: 45.5%). Median iPFS in EGFR 21 was significantly longer than in NCOM (12.0 vs. 6.5 months; 95% CI: 5.16-7.84), and OS was also significantly longer (18.0 vs. 10.2 months; 95% CI: 4.79-15.61) DATA CONCLUSION: This radiogenomics study showed that EGFR mutation subtypes are associated with MRI features and survival outcomes in LUAD-LM patients with poor response to conventional and targeted therapies.

Evidence level: 3 TECHNICAL EFFICACY STAGE: 4.

Background: Liver Imaging Reporting and Data System M (LR-M) lesions may appear targetoid or nontargetoid, but their clinicopathologic and prognostic differences remain unclear.

Purpose: To compare clinical, pathological, and prognostic features of targetoid and nontargetoid LR-M lesions on dynamic contrast enhanced-MRI (DCE-MRI).

Study type: Retrospective.

Subjects: 119 consecutive patients (82 male, mean age = 62.9 ± 10.3 years) with 119 LR-M observations (75 targetoid, 44 nontargetoid) and at least 2 years of follow-up.

Field strength/sequence: 1.5T and 3.0T; T2-weighted fast spin echo sequence, diffusion-weighted image, and dynamic T1-weighted-gradient-echo sequence using an extracellular contrast agent.

Assessment: Three radiologists categorized lesions as targetoid or nontargetoid. Clinical, laboratory, imaging, and histopathologic data were collected.

Statistical tests: Group differences were evaluated using t-tests and chi-square/Fisher's exact tests. Survival outcomes were assessed using Kaplan-Meier method with log-rank test and Cox proportional hazards regression. Inverse probability of treatment weighting (IPTW) was applied before survival analysis. A p-value < 0.05 was considered significant.

Results: The nontargetoid group had significantly higher serum AFP (6684.7 ± 15,988 vs. 194.9 ± 898.4 ng/mL), larger lesion size (9.10 ± 5.55 cm vs. 3.55 ± 2.96 cm), cirrhosis (95% vs. 76%), extrahepatic disease (50% vs. 19%), and malignancy (95% vs. 82%). Nontargetoid group showed significantly higher mortality (75% vs. 41%), progression (77% vs. 45%), shorter overall survival (477 ± 629 vs. 1226 ± 1147 days), and time-to-progression (333 vs. 1003 days). On multivariable analysis with Cox proportional hazards regression, targetoid morphology was significantly associated with improved overall survival (HR = 0.28) and progression-free survival (HR = 0.36), whereas histology was not significant (HCC vs. non-HCC).

Data conclusion: Targetoid morphology is significantly associated with improved survival and delayed progression, supporting its role as a prognostic imaging biomarker.

Evidence level: 3.

Technical efficacy: Stage 5.

Background: Non-contrast coronary MR angiography (CMRA) is a validated, non-invasive, radiation-free technique for coronary stenosis assessment. However, its application to myocardial bridging (MB) is limited, with large-scale evidence for its diagnostic performance lacking.

Purpose: To evaluate the diagnostic accuracy and morphological consistency of non-contrast CMRA for detecting MB, using photon-counting coronary CT angiography (CCTA) as the reference standard.

Study type: Retrospective.

Subjects: One hundred and ninety-six patients with suspected or confirmed coronary artery disease (men: 141; mean age: 62.9 ± 10.6 years) who underwent both photon-counting CCTA and CMRA.

Field strength/sequences: 3.0T; 3D nonselective pulse non-enhanced whole-heart balanced steady-state free precession sequence.

Assessment: The presence and morphology (location, length, depth, stenosis severity) of MB were assessed using both CMRA and CCTA and compared. Diagnostic performance for diagnosing MB using CMRA was calculated.

Statistical tests: Diagnostic performance was assessed using sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV); morphological characteristics of MB were compared using Bland-Altman analysis and intraclass correlation coefficients (ICC). A two-sided p < 0.05 indicated statistical significance.

Results: CCTA identified 92 MBs in 87 patients (44.4%; 82 single- and 5 multi-segment), and CMRA detected 89 MBs in 84 patients (42.9%; 79 single- and 5 multi-segment). CMRA had a diagnostic accuracy of 98.5%, sensitivity of 96.6%, specificity of 100%, NPV of 97.3%, and PPV of 100%. CMRA and CCTA demonstrated excellent agreement in the assessment of morphological characteristics for location (ICC = 0.98), length (ICC = 0.98), and depth (ICC = 0.98), with moderate agreement for stenosis severity (ICC = 0.71).

Data conclusion: Non-contrast CMRA showed excellent diagnostic performance for MB assessment and has potential to be a feasible, non-invasive, radiation-free, and contrast-free alternative to CCTA.

Level of evidence: 3:

Technical efficacy: Stage 2.

Background: In oral tongue squamous cell carcinoma (OTSCC), cervical lymph node metastasis (CLNM) reduces predicted survival by 50%. However, MRI sensitivity for occult nodal disease is only 35.7%, reflecting limited microstructural specificity.

Purpose: To investigate whether diffusion-relaxation correlated spectroscopic imaging (DR-CSI) metrics with peritumoral extensions contribute toward the prediction of CLNM in OTSCC.

Study type: Prospective.

Population: 99 patients (33 female and 66 male) with pathologically confirmed OTSCC.

Field strength/sequence: 3T; a spin-echo echo-planar DR-CSI with 35 contrasts.

Assessment: Tumor-stroma ratio (TSR), density of tumor-infiltrating lymphocytes (TILs), perineural invasion (PNI) and differentiation status were determined from histology. Tumor greatest diameter and depth of invasion (DOI) were evaluated from MRI. Apparent diffusion coefficient (ADC) maps and T₂ maps were derived from DR-CSI data. Five DR-CSI compartmental metrics in intratumoral and peritumoral regions, V_A-V_E, were calculated.

Statistical tests: Mann-Whitney U-test, Chi-square test, or Spearman correlation analysis. Multivariable logistic regression and receiver operating characteristic (ROC) analysis for diagnostic performance. Significance criteria: p < 0.05.

Results: 51 patients were CLNM negative. Intratumoral V_A in the CLNM-positive group (34.80% ± 18.51%) was significantly lower than that in the CLNM-negative group (47.86% ± 23.37%), while V_B (25.07% ± 12.49%) and V_D (22.12% ± 11.46%) in the CLNM-positive group were significantly higher than those in the CLNM-negative group. ADC and T₂ showed no significant separation (p = 0.084, 0.493, respectively). A multivariable logistic model comprising the significant intratumoral and peritumoral DR-CSI metrics (V_A, V_B, and V_D) together with the morphologic variables (tumor greatest diameter and DOI) achieved an area under curve (AUC) value of 0.792 for CLNM classification, representing a non-significant improvement over the morphologic variables model alone (AUC 0.709, p = 0.069).

Data conclusion: The intratumoral and peritumoral DR-CSI metrics, combined with morphologic variables, improved preoperative discrimination of nodal status in OTSCC in this single center cohort, though external validation is warranted.

Evidence level: 2.

Technical efficacy: Stage 2.

Background: Ankle cartilage is prone to degeneration due to overuse. Developing a non-invasive MRI technique to detect early running-induced lesions enables timely intervention.

Purpose: To evaluate the value of the ultrashort echo time magnetization transfer (UTE-MT) sequence in monitoring tibiotalar cartilage changes in amateur marathon runners before and after a marathon.

Study type: Prospective.

Subjects: Thirty amateur marathon runners (25 males, 5 females; range: 24-50 years).

Sequence: 3D UTE-MT (gradient-echo), 3D UTE-T2* (gradient-echo).

Assessment: MRI scans at three time points: 1 week pre-marathon, 2 days post-marathon, and 4 weeks post-marathon. Medial and lateral tibiotalar cartilage was subdivided into 12 subregions, consisting of anterior, middle, and posterior segments for the tibial and talus parts on each side. The UTE-MTR and UTE-T2* values were measured per subregion at each time point.

Statistical tests: Repeated measures one-way ANOVA and the Tukey test. p < 0.05 was considered statistically significant.

Results: Most cartilage subregions showed decreased UTE-MTR values 2 days post-marathon and increased after 4 weeks. Significant differences in UTE-MTR over time were observed in 9 subregions, including the medial and lateral anterior, middle, and posterior tibial cartilage (MTiA, MTiM, MTiP, LTiA, LTiM, LTiP), the medial and lateral posterior talus regions (MTaP, LTaP), and the medial middle talus cartilage (MTaM). Post hoc tests revealed significant UTE-MTR decreases 2 days post-marathon in all 9 regions (Rate: MTiA: -3.9%; MTiM: -2.8%; MTiP: -3.0%; MTaP: -4.5%; MTaM: -4.2%; LTiA: -3.5%; LTiM: -4.7%; LTiP: -5.8%; LTaP: -6.8%), with significant increases in MTiA (3.7%) and MTaM (4.4%) at 4 weeks. UTE-T2* values rose in most cartilage regions at 2 days post-marathon and continued increasing at 4 weeks. Only MTiP, LTiM, and LTaM showed significant changes.

Data conclusion: This study demonstrates that the UTE-MT sequence enables the quantitative assessment of dynamic changes in tibiotalar joint cartilage after a marathon.

Level of evidence: 2:

Technical efficacy: Stage 1.