Use of spiral computerized tomography in lieu of angiography for preoperative assessment of living renal donors

Purpose: We evaluate whether spiral computerized tomography (CT) can be use d in lieu of renal angiography for preoperative assessment of living renal donors, with special attention to multiplicity of renal vasculature. Materials and Methods: A total of 47 living renal donor candidates were eva luated with spiral CT and all but 2 underwent donor nephrectomy. Patients w ere divided into early and late groups because there was a learning curve w ith spiral CT. In the early group 18 donors underwent renal angiography as well as spiral CT and 10 underwent nephrectomy after spiral CT only. In the late group 5 had dual radiographic evaluation for ambiguities in spiral CT interpretation and 12 underwent nephrectomy after spiral CT only. Spiral C T was performed and interpreted blind to angiographic results, and vice ver sa. Results: Spiral CT identified 50 of 52 renal arteries (96%) found at surger y overall and 23 of 25 (92%) found at surgery after spiral CT only. Two acc essory arteries were missed in the 10 early group donors evaluated with spi ral CT only, yielding an early negative predictive value of 80%. Renal angi ography identified another accessory artery missed by spiral CT in the earl y group. All 3 missed vessels were identified retrospectively. No arteries found at surgery were missed in the late group (negative predictive value 1 00%), although there were 2 false-positive results detected by spiral CT re lative to renal angiography in 1 candidate renal unit. Overall accuracy to predict early renal artery division relative to surgica l findings was 93% for spiral CT and 91% for renal angiography. However, ea rly renal artery division was clinically significant for only 1 of 11 vesse ls found at surgery. Spiral CT demonstrated 4 anomalous venous returns and renal angiography identified none. However, spiral CT missed 2 accessory ve ins and identified only 1 of 2 fibromuscular dysplasia cases. Total cost fo r spiral CT and renal angiography was $886 and $2,905, respectively. Conclusions: Spiral CT is a reasonably good alternative to renal angiograph y for living renal donor assessment but there is a profound learning curve for performance and interpretation. Renal angiography is still the gold sta ndard with respect to the identification of arterial multiplicity and fibro muscular dysplasia, and it should be used adjunctively in cases with spiral CT ambiguity. Neither spiral CT nor renal angiography is ideal for the ass essment of early renal artery division which is seldom an issue. The benefi ts of spiral CT over renal angiography are potentially lower morbidity, imp roved donor convenience and reduced cost.