Restricted diffusion MRI as a functional biomarker for the assessment of acute calcular upper urinary tract obstruction: initial experience

Abstract

Abstract Background Acute renal obstruction due to stone is a prevalent scenario. The diffusion-weighted magnetic resonance imaging (DWI) of the kidneys provides a noninvasive information on renal function. Our objective is to prospectively assess the potential role of DWI to predict the signal changes of a kidney with acute calcular obstruction. Results Chi-square and Fissure exact tests were used to assess the association of diffusion signal changes among patients and control groups. Cohen's Kappa test was run to determine the degree of agreement between the two radiologists. An independent sample t-test was performed to assess the significant difference among ADC values between the two groups. Restricted signals of the obstructed kidneys showed a statistically significant difference when compared with contralateral unobstructed kidney and control group with p value (0.001) and (0.01), respectively. Furthermore, there is a moderate agreement between the two radiologists K = 0.7, p = 0. 001. There is no statistically significant difference in ADC values when comparing the obstructed kidney and the contralateral unobstructed kidney of the patient group or with the control group p value (0.06) and (0.05), respectively. Conclusion Restricted signals of the obstructed kidney by DWI may be a helpful tool in diagnosing acute unilateral renal obstruction and can affect its management; however, it needs further validation by more studies.

Keywords

• Magnetic resonance imaging
• Nephrolithiasis
• Diffusion MRI
• Urologic diseases
• Urinary calculi