Ureteral Stone Diameter on Computerized Tomography Coronal Reconstructions Is Clinically Important and Under-reported.

OBJECTIVE: To compare the maximum stone diameter of ureteral stones in the coronal plane to that of stones in the axial plane and to determine the clinical significance of the coronal diameter.

MATERIALS AND METHODS: A retrospective chart review was performed on patients seen in the clinic between September 2013 and November 2015. Patients were included if they had a history of ureteral stone noted on computerized tomography (CT) performed with coronal reconstructions. Patients were excluded if they had multiple ureteral stones, a history of upper urinary tract abnormalities, a need for urgent intervention, or no follow-up. Management of the ureteral stone and pertinent medical history related to patients' stone disease, including stone diameter on axial and coronal CT imaging, were captured. Multivariate regression was performed to identify predictive factors for stone passage.

RESULTS: A total of 150 patients met inclusion criteria. Fifty-four patients spontaneously passed stones and 96 required surgery. The reading radiologist reported the stone measurement in the coronal dimension in 17% of the cases. In 75% of the cases, the coronal diameter was larger than the axial diameter by an average of 1.2 mm. On univariate analysis, stone passage was associated with axial diameter (P <.001), coronal diameter (P <.001), stone location (P = .001), age (P <.001), and medical expulsive therapy (P = .008). On multivariate analysis, only coronal diameter (P <.001), stone location (P = .01), and age (P = .03) remained significant factors associated with spontaneous passage.

CONCLUSION: In the current series, only stone size as measured in the coronal diameter was associated with stone passage vs need for surgical intervention on multivariate analysis. We strongly recommend obtaining coronal reconstructions when CT is performed for ureteral stone to guide management decisions and appropriately counsel patients on the probability of stone passage.