The Influence of Anthropometric Factors on Renal mpMRI: Insights From Regional Analysis

Multiparametric MRI (mpMRI) provides detailed insights into renal function, but the impact of anthropometric factors on renal imaging is not fully understood.

To investigate regional correlations between mpMRI parameters and age, body mass index (BMI), and body surface area (BSA).

Prospective, cross-sectional observational study.

Twenty-nine healthy volunteers (44.5 ± 18.3 years, 18 females) without a history of renal disease.

3-T, pseudo-continuous arterial spin labeling, multi-echo gradient-recalled echo, diffusion-weighted imaging, T₁ and T₂ mapping.

Bilateral kidneys were segmented into nine concentric layers (outer cortex to inner regions) and nine equiangular sections (lower to upper pole). Key parameters (renal blood flow [RBF], $R_2^{*}$ , apparent diffusion coefficient [ADC], T₁ and T₂ maps) were correlated with age, BMI, and BSA. Differences in parameters between age and BMI groups were also evaluated.

Spearman correlation, Mann-Whitney U test, and rank-biserial correlation coefficient for effect size. A P-value <0.05 was considered statistically significant.

RBF correlated negatively with age in all regions and BMI in inner layers and lower pole. ADC negatively correlated with BMI (significance was not reached in layers 2, 7, 8; P-value = 0.06-0.12) and BSA in layers 1-7. T₁ negatively correlated with age in inner regions and lower medial pole. Significant positive correlations were found between age and $R_2^{*}$ (outermost layer, upper pole), age and T₂ (inner and cranial-caudal regions), as well as BMI and T₂ (except upper pole; P-value = 0.06). Significant differences between age groups were observed for RBF (all regions), $R_2^{*}$ (outermost and second innermost layers, central lateral region), T₁ (innermost layer), and T₂ (upper medial pole). Between BMI groups, ADC (middle layers, upper medial pole) and T₂ (outermost and inner layers, lower pole to lateral region) differed significantly.

Intrarenal variance of mpMRI parameters correlated with age, BMI, and BSA.

4 TECHNICAL EFFICACY: Stage 1.