The diagnostic accuracy of opposed-phase and in-phase GRE MR imaging for the differentiation of minimal fat AML and clear cell RCC is poor. In this cohort, low SI on T2-weighted images relative to renal parenchyma and small size suggested minimal fat AML, whereas intratumoral necrosis and large size argued against this diagnosis.

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Although many individuals with ADPKD have a linear decline in eGFR, prolonged intervals of stable GFRs occur in a substantial fraction. Lower body mass index was associated with more stable kidney function in early ADPKD.

Purpose To correlate the magnetic resonance imaging (MRI) features of clear cell renal cell carcinoma (ccRCC) with the histopathological features and disease progression. Material and Methods IRB approval for this retrospective study was obtained; patient consent was not required. The initial staging MRIs of 75 patients with histologically confirmed ccRCC were retrospectively reviewed. The imaging was assessed by two radiologists for the presence of tumor necrosis, cystic degeneration, intracellular fat, hemorrhage, retroperitoneal collaterals and renal vein thrombosis. Quantitative analysis for the MRI presence of intracellular lipid within tumors was performed. MRI findings were correlated with histopathologic findings of clear cell percentage, alveolar and tubular growth pattern and disease progression. Statistical associations were evaluated with non-parametric univariable analyses and multivariable logistic regression models. Results Correlation between MRI and histopathologic features was performed in 75 patients whereas follow-up data was available for progression analysis in 68 patients. The presence of tumor necrosis, retroperitoneal collaterals and renal vein thrombosis on MRI were significantly associated with low percentage of tumor cells with clear cytoplasm (p<0.01) and with metastatic disease at presentation or disease progression (p<0.01). At multivariable analysis, necrosis remained as the only feature statistically associated with disease progression (p=0.03, adjusted odds ratio=27.7, CI 95%=1.4–554.7 for reader one and p=0.02, adjusted odds ratio=29.3, CI 95%=1.7–520.8 for reader two). Conclusion Necrosis in ccRCC on MRI correlates with the histopathological finding of lower percentage of tumor cells with clear cytoplasm and is a poor prognostic indicator irrespective of tumor size.

Background Noninvasive quantitative measurement of fibrosis in chronic kidney disease (CKD) would be desirable diagnostically and therapeutically but standard radiologic imaging is too variable for clinical usage. By applying a vibratory force, tissue shear wave stiffness can be measured by magnetic resonance elastography (MRE) that may correlate with progression of kidney fibrosis. Since decreased kidney perfusion decreases tissue turgor and stiffness, we combined newly available three-dimensional MRE shear stiffness measurements with MR arterial spin labeling (ASL) kidney blood flow rates to evaluate fibrosis in diabetic nephropathy. Methods Thirty individuals with diabetes and Stage 0–5 CKD and 13 control individuals without CKD underwent noncontrast MRE with concurrent ASL blood flow measurements. Results MRE cortical shear stiffness at 90 Hz was decreased significantly below controls in all CKD stages of diabetic nephropathy. Likewise, ASL blood flow decreased progressively from 480 ± 136 mL/min/100 g of cortical tissue in controls to 302 ± 95, 229 ± 7 and 152 ± 32 mL/min/100 g in Stages 3, 4 and 5 CKD, respectively. A magnetic resonance imaging (MRI) surrogate for the measured glomerular filtration fraction [surrogate filtration fraction = estimated glomerular filtration rate (eGFR)/ASL] decreased progressively from 0.21 ± 0.07 in controls to 0.16 ± 0.04 in Stage 3 and 0.10 ± 0.02 in Stage 4–5 CKD. Conclusions In this pilot study, MRI with ASL blood flow rates can noninvasively measure decreasing kidney cortical tissue perfusion and, with eGFR, a decreasing surrogate filtration fraction in worsening diabetic nephropathy that appears to correlate with increasing fibrosis. Differing from the liver, MRE shear stiffness surprisingly decreases with worsening CKD, likely related to decreased tissue turgor from lower blood flow rates.