Can renal dimensions and the main renal artery diameter indicate the presence of an accessory renal artery? A 64-slice CT study.

PURPOSE To evaluate whether renal dimensions and the main renal artery (mRA) diameter can provide indirect evidence of the presence or absence of accessory renal arteries (aRA). MATERIALS AND METHODS The study group consisted of 167 patients (83 women, 84 men; mean age, 52.4±13.1 years) who presented to our radiology department for abdominal CT examinations with various indications. CT examination was performed on a 64-slice CT scanner in the arterial phase. The kidney diameters were recorded. The number of renal arteries supplying each kidney was evaluated, and their diameters were measured. We attempted to determine a formula that could be used to predict the presence or absence of aRAs. RESULTS One or multiple aRAs were found in 76 (22.8%) of the 334 kidneys. The mRA diameter was 5.51±0.96 mm. The mRA diameter was smaller in kidneys with aRAs than in those without (P < 0.001). A cut-off value of 4.15 mm for the diameter of mRA to predict the presence of aRAs led to negative and positive predictive values of 80% and 90%, respectively. A formula that can predict that an aRA is absent with 97% accuracy given the values of the mRA diameter and the kidney length was determined using logistic regression. CONCLUSION The mRA diameter (4.15 mm) alone and the results of the formula developed herein employing the mRA diameter and kidney length can respectively predict the presence or absence of an aRA with high accuracy.