Abstract
Background: The prevalence and recurrence of urolithiasis are high; particularly in the north-western part of India. Ultrasonography has poor sensitivity and specificity compared to Non Contrast Computed Tomography (CT) for detection of both renal and ureteral calculi. Drawbacks of Non contrast CT include radiation exposure which can be overcome by low-dose CT protocols. Low-dose CT may be a useful investigation with high diagnostic accuracy and less radiation hazards in evaluating urolithiasis.
Aim: To compare efficacy of low-dose non contrast CT with standard-dose CT in the detection of urolithiasis
Material and Methods: Fifty cases of clinically suspected urolithiasis underwent both abdominal standard-dose CT (140 mAs) and low-dose CT (70 mAs) with fixed kVp (120). Patients with BMI <30 (non obese) were included in the study. Both the scans were independently reviewed by two radiologists for the characterization of urolthiasis and any indirect signs of renal and ureteral colic. Results for low-dose CT were compared with those obtained with standard-dose CT (reference standard).
Results: Majority of patients were seen in 3rd decade with male to female ratio of 1:8. Eighty Eight calculi were detected in 50 patients. Low-dose CT had approx. 82% and 100% sensitivity in identifying renal calculi <5mm and >5mm size respectively while it had approx. 92% sensitivity for the detection of ureteric calculi. Mean effective radiation dose in standard-dose CT and low-dose CT was 2.1 mSv and 4.3 mSv respectively.
Conclusions: Low-dose CT provides effective method of identifying and evaluating urolthiasis with high diagnostic accuracy and sensitivity and significant dose reduction as compared to standard-dose CT.
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Corresponding Author
Manik Mahajan
House no 109, Sector-7, Channi Himmat, Jammu (J&K), India – 180015
DOI: https://dx.doi.org/10.18535/jmscr/v7i6.96
