Diffusion-weighted MRI in assessment of renal dysfunction

BACKGROUND: Diffusion-weighted magnetic resonance imaging (DW-MRI) in renal diseases is an evolving field and its potential is yet to be fully realized. PURPOSE: To study the relationship between apparent diffusion coefficient (ADC) values of renal parenchyma and serum markers of renal function and stage of chronic kidney disease (CKD). MATERIALS AND METHODS: A retrospective review was performed of all adult patients who underwent DW-MRI (at b-values of 0 and 500 s/mm(2)) for renal lesions from January 2009 to September 2010 and revealed 88 patients, of which 22 patients had renal dysfunction and 66 had normal renal function. Of these 22, 15 patients were known cases of CKD and were staged depending on disease severity. ADC values were determined for renal parenchyma and compared. Receiver operating characteristic (ROC) curves were drawn to establish cut-off ADC values. Pearson's correlation coefficient (R) was calculated between ADC and renal function parameters. RESULTS: ADC values in patients with renal dysfunction were significantly lower than in patients with normal renal function (2.1133 ± 0.2851 vs. 2.3198 ± 0.1246 (×10(-3) mm(2)/s)). ADC values lower than 2.0354 (×10(-3) mm(2)/s) were seen only with renal dysfunction and higher than 2.4516 (×10(-3) mm(2) /s) were seen only with normal function. There was significant inverse correlation between ADC and serum creatinine (R = -0.530), blood urea (R= -0.502), and significant linear correlation (R = 0.784) with estimated glomerular filtration rate (eGFR). ADC values showed a statistically significant decreasing trend with increasing stage of CKD. CONCLUSION: ADC values may serve as an additional marker for the presence and degree of renal dysfunction.