Diffusion-weighted MRI of the kidneys in patients with familial Mediterranean fever: initial experience

To evaluate the feasibility of diffusion-weighted magnetic resonance imaging (DW-MRI) in the assessment of renal function in patients with familial Mediterranean fever (FMF).

Thirty healthy volunteers who had no history of renal disease, hypertension or vascular disease and 60 patients with FMF were included in the study. Transverse diffusion-weighted multisection echo-planar MRI was performed with the following diffusion gradient b values: 0, 111, 222, 333, 444, 556, 667, 778, 889 and 1000 s/mm(2). The apparent diffusion coefficient (ADC) values, urine protein and serum creatinine levels, and glomerular filtration rates of the healthy volunteers, patients with renal involvement, and patients without were compared by using ANOVA test. ADCs of the kidneys were calculated separately for low (ADC(low); b = 0, 111, 222, 333 s/mm(2)), average (ADC(avg); of all b values), and high (ADC(high); b = 778, 889, 1000 s/mm(2)) b values to enable the differentiation of the relative influence of perfusion fraction and true diffusion. ADC(high) reflects almost only diffusion, whereas ADC(low) is composed of both diffusion and perfusion.

There was statistically significant difference between ADC(low) values of the FMF patients with renal involvement and the control group (P < 0.05). Negative correlation was found between the duration of disease and ADC(low) values of the kidneys (r = -0.223, P = 0.087).

DW-MRI of the kidneys might allow early detection of the renal changes in patients with FMF. This might prevent the progression of disease by giving proper medical treatment. Further studies with larger numbers of FMF patients and more experience on MRI technique are required to help define more conclusively the precise role of DW imaging in detection of renal changes.