MR findings in diffuse renal parenchymal disease

This study evaluates the MR appearance of the kidney in diffuse renal parenchymal diseases, using precontrast, and immediate and delayed postgadolinium chelate (Gd), spoiled gradient echo (SGE), and pre- and post-Gd, T1-weighted, fat-suppressed spin-echo MR images to determine if characteristic findings exist for various types of renal disease. One hundred twenty-one patients with renal disease underwent MRI. Underlying diagnoses included: (a) glomerular disease (GD), (b) tubulointerstitial disease (TID), (c) microvascular disease (MVD), (d) ischemic nephropathy (INP), (e) obstructive nephropathy (ON), (f) infectious renal disease (IRD), (g) sickle cell disease (SCD), (h) renal cortical necrosis (CN), and (i) renal insufficiency of unknown etiology (UE). MR examinations of 22 patients with normal kidneys (NK) were evaluated as a control group. The presence of corticomedullary differentiation (CMD) demonstrated strong inverse correlation with serum creatinine concentration (SCr) (r = -.568, P <.001). Mean thickness of the renal cortex was 8.4 and 7.8 mm in patients with NK and Gd, respectively. The mean cortical thickness in patients with MVD, TID/Chemo, INP, and ON was 5.2, 5.6, 5.5, and 4.3 mm, respectively, significantly thinner than the renal cortex in the NK and GD groups (P <.01). Irregularity of the renal cortex was more frequent in MVD (60.9%), IRD (62.5%). ON (55.6%). and TID/other (53.8%) than in GD (3.8%) and NK (0%) (P <.01). Diffuse high SI of the entire medulla on delayed postcontrast images was observed in 25 (20.7%) of the patients with renal disease and none of the NK group. Although no pathognomonic features were found, certain findings were observed that may correlate with the etiology of the kidney disease and, therefore, assist in the differential diagnosis of renal parenchymal disease.