Non-Invasive Assessment of Carotid Perivascular Adipose Tissue Phenotyping and Calcific Burden Using MRI Fat Fraction
Jun Zhou1,2,3, Shi-Feng Cai4, Jian-Jun Xiu4
1Affiliated Hospital of Jining Medical University, Jining, China.
Background:
Perivascular adipose tissue (PVAT) attenuation elevation, as measured by computed tomography angiography (CTA), indicates localized vascular inflammation. Dixon-based fat fraction (FF) and R2* mappings, established for assessing carotid high-risk plaque components, demonstrate potential for quantifying PVAT phenotypic changes and calcification burden. However, studies validating FF/R2* mappings against CTA attenuation metrics are lacking.
Purpose:
To assess the correlation between FF/R2* mappings and CTA measurements in evaluating carotid PVAT characteristics and calcification burden.
Study Type:
Prospective validation study.
Population/Subjects:
Twenty five patients with ultrasonographically-confirmed carotid atherosclerotic plaque (62.3 ± 11.3 years) having matched carotid CTA/MRI and five healthy volunteers (36.2 ± 11.9 years).
Field Strength/Sequence:
3T, 3D multi-echo Dixon sequence for co-registered FF/R2* mapping.
Assessment:
Volunteers were scanned twice on the same day (with removal from scanner between scans) to assess scan-rescan reproducibility of FF mapping. PVAT FF values and calcification burden measured on Dixon-derived FF and R2* maps, respectively, were compared to spatially matched CTA Hounsfield units (HU) and calcification volumetry in the atherosclerosis cohort.
Statistical Tests:
Intraclass correlation coefficient (ICC), Pearson correlation coefficients (R), and Bland-Altman analysis. A p-value < 0.05 was considered significant.
Results:
Dixon imaging demonstrated high scan-rescan reproducibility for PVAT FF quantification (ICC = 0.982). In patients, PVAT FF exhibited a strong inverse correlation with CTA HU values (R = -0.868). R2* mapping achieved near-perfect agreement with CTA in calcification volumetry across 40 calcified carotids (R = 0.991).
Conclusion:
FF/R2* mappings show excellent agreement with CTA for PVAT phenotyping and calcific burden quantification, while potentially enabling simultaneous assessment of vascular inflammation and high-risk plaque components.
Evidence Level:
2.
Technical Efficacy:
Stage 2.
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