Magn Reson Med. 2023 Apr 24.
Feng Wang,
Seo Yeon Lee,
Fatemeh Adelnia,
Keiko Takahashi,
Kevin D Harkins,
Lilly He,
Zhongliang Zu,
Philipp Ellinger,
Manuel Grundmann,
Raymond C Harris,
Takamune Takahashi,
John C Gore.
PURPOSE: We aimed to compare multiple MRI parameters, including relaxation rates ( R1$$ {R}_1 $$ , R2$$ {R}_2 $$ , and R1ρ$$ {R}_{1\rho } $$ ), ADC from diffusion weighted imaging, pool size ratio (PSR) from quantitative magnetization transfer, and measures of exchange from spin-lock imaging ( Sρ$$ {S}_{\rho } $$ ), for assessing and predicting the severity of polycystic kidney disease (PKD) over time.
METHODS: Pcy/Pcy mice with CD1 strain, a mouse model of autosomal dominant PKD, were imaged at 5, 9, and 26 wk of age using a 7T MRI system. Twelve-week normal CD1 mice were used as controls. Post-mortem paraffin tissue sections were stained using hematoxylin and eosin and picrosirius red to identify histological changes.
RESULTS: Histology detected segmental cyst formation in the early stage (week 5) and progression of PKD over time in Pcy kidneys. In T2$$ {T}_2 $$ -weighted images, small cysts appeared locally in cystic kidneys in week 5 and gradually extended to the whole cortex and outer stripe of outer medulla region from week 5 to week 26. Regional PSR, R1$$ {R}_1 $$ , R2$$ {R}_2 $$ , and R1ρ$$ {R}_{1\rho } $$ decreased consistently over time compared to normal kidneys, with significant changes detected in week 5. Among all the MRI measures, R2$$ {R}_2 $$ and R1ρ$$ {R}_{1\rho } $$ allow highest detectability to PKD, while PSR and R1$$ {R}_1 $$ have highest correlation with pathological indices of PKD. Using optimum MRI parameters as regressors, multiple linear regression provides reliable prediction of PKD progression.
CONCLUSION: R2$$ {R}_2 $$ , R1$$ {R}_1 $$ , and PSR are sensitive indicators of the presence of PKD. Multiparametric MRI allows a comprehensive analysis of renal changes caused by cyst formation and expansion.
Keywords: MRI; diffusion weighted imaging; magnetization transfer; polycystic kidney disease (PKD); relaxation; spin-lock