Can Unenhanced CT Findings Predict Interventional Versus Conservative Treatment in Acute Renal Colic?

The purpose of this study was to determine the value of clinical parameters and radiologic findings on unenhanced CT to the choice between interventional and conservative management for patients with acute renal colic.

Unenhanced CT records of 183 consecutive patients with acute renal colic were retrospectively reviewed. Urolithiasis was confirmed at both unenhanced CT and clinical follow-up findings of 80 patients (study group). Clinical parameters (signs of infection and renal indexes) and unenhanced CT findings (tissue rim sign, hydronephrosis, perinephric and periureteral edema, ureteral dilatation, renal attenuation, and stone characteristics) were graded and correlated with the choice of clinical management. ROC analysis was constructed for the most statistically significant parameters.

Forty-two patients (52%) were treated conservatively and 38 (48%) underwent interventional treatments. The relationship between shivering, fever, and leukocytosis and interventional treatment had low sensitivity (29%, 26%, and 16%, respectively) but very high specificity (98%, 95%, and 98%, respectively) (p < 0.05). Stone size and density were statistically significantly different between patients treated conservatively and those treated interventionally (size, 4.6 vs 6.7 mm; density, 730 vs 910 HU; p < 0.01). Stones larger than 6.5 mm with an attenuation value greater than 1100 HU and that were proximally located were more likely to be treated interventionally.

Larger stone size, higher density, proximal location, and complaints of shivering, fever, and leukocytosis are the most important parameters for predicting invasive management of acute renal colic. Other clinical and radiologic information may be useful as supportive findings but do not predict the choice of patient management.