T2 weighted MRI for assessing renal lesions in transgenic mouse models of tuberous sclerosis

Abstract

ObjectiveTransgenic mouse models of tuberous sclerosis (TSC) develop renal cysts, cystadenomas, solid adenomas and carcinomas. Identification and characterisation of these lesions in vivo may help in TSC pre-clinical trials. This study was to evaluate T2 weighted MRI for assessment of renal lesions in two Tsc mouse models. Materials and MethodsTsc1+/−, Tsc2+/− and wild type mice were subjected to a first MRI scan at 12 months of age and a second scan 2 months later. One Tsc2+/− mouse was treated with rapamycin for two months after the initial scan. Immediately following the second scan, mice were sacrificed and MRI images were compared to renal histological findings. ResultsMRI identified all types of Tsc-associated renal lesions in both Tsc1+/− and Tsc2+/− mice. The smallest detectable lesions were <0.1mm3. Eighty three percent of all renal lesions detected in the first scan were re-identified in the second scan. By MRI, these lesions demonstrated significant growth in the 9 untreated Tsc1+/− and Tsc2+/− mice but shrinkage in the rapamycin treated Tsc2+/− mouse. Between the two scans, MRI also revealed significant increase in both the total number and volume of lesions in untreated mice and decrease in the rapamycin treated mouse, respectively. In comparison to histological analysis MRI detected most cysts and cystadenomas (66%) but only a minority of solid tumours (29%). ConclusionThese results suggest that T2 weighted MRI may be a useful tool for assessing some renal lesions in pre-clinical studies using Tsc mouse models. However, improved sensitivity for T2 weighted MRI is required, particularly for solid renal lesions.