Radiology: Diffusion-weighted MRI promising for ureteral obstruction diagnosis
Diffusion-weighted MRI allows for the noninvasive detection of changes in renal perfusion and diffusion during acute unilateral ureteral obstruction, according to a study in this month’s issue of Radiology.
Actute unilateral ureteral obstruction due to kidney stones happens quite frequently. According to Harriet C. Thoeny, MD, of the departments of radiology, neuroradiology and nuclear medicine at the University Hospital of Bern in Switzerland and colleagues, it affects 5 to 15 percent of the population worldwide.
If untreated, acute ureteral obstruction can lead to a decrease in renal blood flow and glomerular filtration rate, resulting in interstitial fibrosis and irreversible renal damage. Consequently, the authors said that early noninvasive and accurate diagnosis with prompt treatment is crucial in order to restore renal function. The purpose of the study was to assess the potential of noninvasive diffusion-weighted MR imaging to depict changes in microperfusion and diffusion in patients with acute unilateral ureteral obstruction.
The researchers studied 21patents (19 men, mean age 43 years), who had been referred to treatment due to acute flank pain, between October 2006 and July 2008.
No significant differences were observed between a single total apparent diffusion coefficient (ADC) of the medulla or cortex of the obstructed and unobstructed kidneys, Thoeny and colleagues reported. However, they wrote that the ADC value in the medulla of the obstructed and unobstructed kidneys was significantly higher than that in control subjects. The perfusion fraction of the cortex of the obstructed kidney was significantly lower than that in the unobstructed kidney, and in the medulla it was slightly lower in the obstructed kidney than in the unobstructed kidney.
Overall, they found that diffusion-weighted MRI can help detect perfusion and diffusion differences in the obstructed kidney compared with the contralateral unobstructed kidney during acute unilateral ureteral obstruction.
According to the authors, “the diagnosis of obstruction limited to the detection of a dilated collecting system on imaging studies can be misleading because a nondilated collecting system does not exclude the presence of an obstruction.”
In situations like these, Thoeny and colleagues said, diffusion-weighted MRI as a noninvasive method without the use of contrast material and radiation, could help physicians make treatment decisions and avoid unnecessary procedures.
Actute unilateral ureteral obstruction due to kidney stones happens quite frequently. According to Harriet C. Thoeny, MD, of the departments of radiology, neuroradiology and nuclear medicine at the University Hospital of Bern in Switzerland and colleagues, it affects 5 to 15 percent of the population worldwide.
If untreated, acute ureteral obstruction can lead to a decrease in renal blood flow and glomerular filtration rate, resulting in interstitial fibrosis and irreversible renal damage. Consequently, the authors said that early noninvasive and accurate diagnosis with prompt treatment is crucial in order to restore renal function. The purpose of the study was to assess the potential of noninvasive diffusion-weighted MR imaging to depict changes in microperfusion and diffusion in patients with acute unilateral ureteral obstruction.
The researchers studied 21patents (19 men, mean age 43 years), who had been referred to treatment due to acute flank pain, between October 2006 and July 2008.
No significant differences were observed between a single total apparent diffusion coefficient (ADC) of the medulla or cortex of the obstructed and unobstructed kidneys, Thoeny and colleagues reported. However, they wrote that the ADC value in the medulla of the obstructed and unobstructed kidneys was significantly higher than that in control subjects. The perfusion fraction of the cortex of the obstructed kidney was significantly lower than that in the unobstructed kidney, and in the medulla it was slightly lower in the obstructed kidney than in the unobstructed kidney.
Overall, they found that diffusion-weighted MRI can help detect perfusion and diffusion differences in the obstructed kidney compared with the contralateral unobstructed kidney during acute unilateral ureteral obstruction.
According to the authors, “the diagnosis of obstruction limited to the detection of a dilated collecting system on imaging studies can be misleading because a nondilated collecting system does not exclude the presence of an obstruction.”
In situations like these, Thoeny and colleagues said, diffusion-weighted MRI as a noninvasive method without the use of contrast material and radiation, could help physicians make treatment decisions and avoid unnecessary procedures.