FAT-RICH VS FAT-POOR RENAL AML ON MULTIPARAMETRIC MRI.

Abstract

Background: The study aims to show the MRI imaging features of Fat-rich and Fat-poor AML using MULTIPARAMETRIC renal MRI protocol. Fat-poor angiomyolipomas (AMLs) are challenging to differentiate from other renal lesions on USG and CT and often necessitate biopsy or surgery for differentiation. The Methods: study group consisted of 9 patients with histologically proven AMLs who underwent MULTIPARAMETRIC renal MRI (T2WI, Chemical Shift imaging, DWI,) before the histopathology. The lesions were reviewed independently by a radiologist and a resident. On T2-weighted images, among Fat rich AML (n=2 i.e. 66%) showed heter Results: ogeneous hyperintense signal and (n=1 i.e. 33%) showed homogenous hyperintense signal as compared to renal cortex. Among Fat Poor AML (n=4 i.e. 66%) showed homogenous hypointense signal and (n=2 i.e. 33%) showed heterogeneous hypointense signal as compared to renal cortex. On Chemical Shift Imaging, among Fat rich AML, mean Signal Intensity drop (%) on out of phase imaging for Fat rich AML in our study was 27.07%±1.65%. Also Fat rich AML (n=3 i.e. 100%) showed Indian Ink Artifact within the mass or at its interface with the kidney. Among Fat Poor AML, mean Signal Intensity drop (%) on out of phase imaging for Fat poor AML in our study was 0.6%±6.7% (p value <0.001). On Diffusion Weighted Imaging, apparent diffusion coefcient (ADC) maps show low ADC values regardless of the types of AML, because fat signal intensity is suppressed. among Fat rich AML mean ADC values of lesion in our study was 0.86±0.09, Among Fat Poor AML, mean ADC values of lesion in our study was 0.96±0.01. Conclusion: Our study enables us to conrm consistent associations of MR imaging features with specic subtypes of AML. In our study, T2 signal intensity, T2 signal intensity ratio, signal drop on out of phase imaging, showed promising results differentiating between fat rich and fat poor AML