Critically Appraised Topics: Is non-contrast helical computed tomography superior to intravenous pyelography for the diagnosis of renal colic?
Sunil Sookram, Michael J. Bullard
2000
CJEM: Canadian Journal of Emergency Medical Care
1. Miller O, Rineer S, Reichard S, Buckley R, Donovan M, Graham I, et al. Prospective comparison of unenhanced spiral computed tomography and intravenous urogram in the evaluation of acute flank pain. Urology 1998;52:982-7. 2. Sourtzis S, Thibeau JF, Damry N, Raslan A, Vandendris M, Bellemans M. Radiologic investigation of renal colic: unenhanced helical CT compared with excretory urography. These and other studies show that non-contrast helical CT (NCCT) is more sensitive and specific than
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... avenous pyelography (IVP) for the diagnosis of renal and ureteral stones. In addition, NCCT often demonstrates alternate pathology not evident on IVP and eliminates the risk of allergic reactions and contrast-mediated nephrotoxicity. Literature search Using MEDLINE (1966-present): 1. exp. tomography, x-ray computed 107203 2. exp. urography 14403 3. exp. ureteral calculi 3208 4. 1 and 2 1004 5. 4 and 3 25 We then identified those trials that prospectively compared NCCT to IVP and were published in English. The evidence Design: Prospective comparison of NCCT and IVP using independent radiologists blinded to the findings of the alternate diagnostic study. Population: 106 patients (article 1; Miller et al) and 53 patients (article 2; Sourtzis et al), 18 years of age or older, with suspected renal colic. Exclusion criteria included a history of contrast allergy or serum creatinine levels > 180 μmol/L. Intervention: All patients underwent NCCT and IVP. Treating physicians had access to both tests, but radiologists who interpreted the NCCT or IVP were blinded to the alternate imaging study. Outcomes measured: The sensitivity and specificity of each imaging modality were calculated against a (positive) gold standard of stone recovery or lithotripsy versus a (negative) gold standard of symptom resolution without stone recovery. Alternate diagnoses identified by CT scans were also documented. Results: In the Miller study, 75 (71%) of 106 patients had urolithiasis (based on the gold standard). Sensitivity and specificity for NCCT were 96% and 100%, while the corresponding values for IVP were 87% and 94%. In the Sourtzis study, 36 (68%) of 53 patients had urolithiasis. Sensitivity and specificity of NCCT were 100% and 100%, while the corresponding values for IVP were 67% and 100%. Combining these data allows us to derive the estimates of sensitivity, specificity, positive likelihood ratio (LR+) and negative likelihood ratio (LR−) shown in Table 1 . Among the patients who had no follow-up evidence of urolithiasis, NCCT provided several alternate diagnoses, including 3 bladder calculi (one visible on IVP), 3 ovarian or uterine masses, 2 renal cysts (one, a renal carcinoma, was also visible on IVP), 1 pyelonephritis, and 1 aortic aneurysm. One patient in the combined series experienced a mild contrast reaction. Comments Not all patients with renal colic require emergency department (ED) imaging, but for those who do, these authors provide us useful information. The referenced studies demonstrate that NCCT is more accurate than IVP for the diagnosis CRITICALLY APPRAISED TOPICS
doi:10.1017/s1481803500004383
fatcat:nst66l25dffdvouw4wnjl7g3lm