MR imaging of segmental renal infarction: an experimental study.

An experimental study was performed in 12 rabbits to evaluate the magnetic resonance (MR) imaging findings of segmental renal infarction. Three or four MR examinations were performed at 6 h, 1 day, 3 days, 1 week, 2 weeks, and 4 weeks following the ligation of segmental artery of the left kidney. The signal intensities of the infarcted area on both T1- and T2-weighted (T1W and T2W, respectively) images were lower than those of the non-affected area in the 6 h group, and pathological examination showed mild interstitial oedema and haemorrhage. The signal intensities of the lesion became higher on T1W images and higher or mixed on T2W scans in the 1 day group, in which the pathological findings were intense interstitial haemorrhage, interstitial oedema, and early coagulative necrosis. The signal intensities of the lesion on both pulse sequences were also higher in the 3 day and 1 week groups in which pathological examination showed progressive coagulative necrosis. The signal intensities of the lesions in the 2 and 4 week groups were lower on both pulse sequences, and the pathological finding was organizing fibrosis. Post-contrast T1W images demonstrated well the extent of the infarction in all but two cases, in which the signal intensities of the lesions were higher on pre-contrast T1W scans.