Accuracy of bladder stone detection using abdominal X-ray after spinal cord injury

Background: Bladder calculi are a common problem in those with spinal cord injury (SCI). Detection is important to prevent complications. Objective: To determine the accuracy of bladder stone detection by abdominal x-rays. Methods: X-ray reports from individuals with SCI with known bladder stones detected by cystoscopy were reviewed. Main outcome measures: x-ray reports noted the presence or absence of bladder stones. The stone variables evaluated were stone composition (crystallographic analysis), widest dimension of the largest stone (during cystoscopy), and the total volume (cm 3) of the stone mass removed. Results: Sixty-two consecutive x-ray reports from individuals with bladder stones were reviewed. The majority of stones were calcium phosphate (46.8%) or struvite (26.7%). Regarding stone composition, the detection by x-ray was 28.6% for struvite stones and 41.9% for calcium phosphate stones. Regarding diameter of largest stone, the detection by x-ray was 14% for stones <0.5 cm, 0% for stones 0.5 cm to 0.9 cm, 33% for stones 1.0 cm to 1.49 cm, 33% for stones 1.5 cm to 1.9 cm, and 54% for stones <0.5 cm, 0% Regarding total volume of stones, the detection by x-ray was 0% for volumes <0.2 cm(3), 33% for volumes 0.2 cm(3) to 0.39 cm(3), 60% for volumes 0.40 cm(3) to 0.59 cm(3), 40% for volumes of 0.60 cm(3) to 0.79 cm(3), 0% for stones from 0.8 cm(3) to 0.99 cm(3), and 57% for volumes greater than or equal to 1.0 cm(3). Overall, 13/62 (20.97%) of stones found during cystoscopy were detected by the x-ray. Conclusion: Abdominal x-ray is not a reliable method to detect bladder stones in individuals with SCI.