Is quantitative diffusion-weighted MRI a valuable technique for the detection of changes in kidneys after extracorporeal shock wave lithotripsy?
OBJECTIVE
The aim of this study was to evaluate the capability and the reliability of diffusion-weighted imaging (DWI) in the changes of kidneys occurring after extracorporeal shock wave lithotripsy (ESWL) treatment for renal stones.


METHODS
A total of 32 patients who underwent ESWL treatment for renal stone disease between June and December 2011 were enrolled in this prospective study. Color Doppler ultrasonography (CDUS) and DWI were performed before and within 24 hours after ESWL. DWI was obtained with b factors of 0, 500 and 1000 s/ mm2 at 1.5 T MRI. Each of Resistive index (RI) and ADC values were calculated from the three regions of renal upper, middle and lower zones for both of the affected and contralateral kidneys. Paired sample t test was used for statistical analyses.


RESULTS
After ESWL, the treated kidneys had statistically significant lower ADC values in all different regions compared with previous renal images. The best discriminative parameter was signal intensity with a b value of 1000 s/mm2. The changes of DWI after ESWL were noteworthy in the middle of the treated kidney (p < 0.01). There were no significant difference between RI values in all regions of treated and contralateral kidneys before and after treatment with ESWL (p>0.05).


CONCLUSIONS
DWI is a valuable technique enables the detection of changes in DWI after ESWL treatment that may provide useful information in prediction of renal damage by shock waves, even CDUS is normal.
Department of Radiology, Bakirkoy Dr. Sadi Konuk Research and Training Hospital, Istanbul, Turkey.
Elif
E
Hocaoglu
Department of Radiology, Bakirkoy Dr. Sadi Konuk Research and Training Hospital, Istanbul, Turkey.
Ercan
E
Inci
Department of Radiology, Haydarpasa Numune Research and Training Hospital, Istanbul, Turkey.
Sibel
S
Aydin
Department of Radiology, Bakirkoy Dr. Sadi Konuk Research and Training Hospital, Istanbul, Turkey.
Dilek Hacer
DH
Cesme
Department of Urology, Bakirkoy Dr. Sadi Konuk Research and Training Hospital, Istanbul, Turkey.
Nadir
N
Kalfazade
D000328:Adult; D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019220:High-Energy Shock Waves / Q000009:adverse effects; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging / Q000528:radiation effects*; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy / Q000009:adverse effects* / Q000379:methods; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome; D018615:Ultrasonography, Doppler, Color; D055815:Young Adult