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 used 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 evaluated with spiral CT and all but 2 underwent donor nephrectomy. Patients were divided into early and late groups because there was a learning curve with 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 CT was performed and interpreted blind to angiographic results, and vice versa.

RESULTS

Spiral CT identified 50 of 52 renal arteries (96%) found at surgery overall and 23 of 25 (92%) found at surgery after spiral CT only. Two accessory arteries were missed in the 10 early group donors evaluated with spiral CT only, yielding an early negative predictive value of 80%. Renal angiography identified another accessory artery missed by spiral CT in the early group. All 3 missed vessels were identified retrospectively. No arteries found at surgery were missed in the late group (negative predictive value 100%), although there were 2 false-positive results detected by spiral CT relative to renal angiography in 1 candidate renal unit. Overall accuracy to predict early renal artery division relative to surgical findings was 93% for spiral CT and 91% for renal angiography. However, early renal artery division was clinically significant for only 1 of 11 vessels found at surgery. Spiral CT demonstrated 4 anomalous venous returns and renal angiography identified none. However, spiral CT missed 2 accessory veins and identified only 1 of 2 fibromuscular dysplasia cases. Total cost for spiral CT and renal angiography was $886 and $2,905, respectively.

CONCLUSIONS

Spiral CT is a reasonably good alternative to renal angiography for living renal donor assessment but there is a profound learning curve for performance and interpretation. Renal angiography is still the gold standard with respect to the identification of arterial multiplicity and fibromuscular dysplasia, and it should be used adjunctively in cases with spiral CT ambiguity. Neither spiral CT nor renal angiography is ideal for the assessment of early renal artery division which is seldom an issue. The benefits of spiral CT over renal angiography are potentially lower morbidity, improved donor convenience and reduced cost.