Adrenal venous sampling in primary hyperaldosteronism: correlation of hormone indices and collimated C-arm CT findings

PURPOSE: To evaluate the feasibility and effect of an approach to adrenal venous sampling (AVS) analysis by combining established selective cortisol and aldosterone indices with the acquisition of a collimated C-arm CT(CACT(Coll)). METHODS: Overall, 107 consecutive patients (45f,62 m; 54 ± 10 years) undergoing 111 AVS procedures without hormonal stimulation from 7/13 to 2/20 in a single institution were retrospectively analysed. Hormone levels were measured in sequential samples of the suspected adrenal veins and right iliac vein, and selectivity indices (SI) computed. Stand-alone SI(Cortisol) and/or SI(Aldosterone) ≥ 2.0 as well as SI(Cortisol) and/or SI(Aldosterone) ≥ 1.1 combined with positive right-sided CACT(Coll) of the adrenals (n = 80; opacified right adrenal vein) were defined as a successful AVS procedure. Radiation exposure of CACT was measured via dose area product (DAP) and weighed against an age-/weight-matched cohort (n = 66). RESULTS: Preliminary success rates (SI(Cortisol) and/or SI(Aldosterone) ≥ 2.0) were 99.1% (left) and 72.1% (right). These could be significantly increased to a 90.1% success rate on the right, by combining an adjusted SI of 1.1 with a positive CACT(Coll) proving the correct sampling position. Sensitivity for stand-alone collimated CACT (CACT(Coll)) was 0.93, with 74/80 acquired CACT(Coll) confirming selective cannulation by adrenal vein enhancement. Mean DAP(Coll_CACT) measured 2414 ± 958 μGyxm(2), while mean DAP(Full-FOV_CACT) in the matched cohort measured 8766 ± 1956 μGyxm(2) (p < 0.001). CONCLUSION: Collimated CACT in AVS procedures is feasible and leads to a significant increase in success rates of (right-sided) selective cannulation and may in combination with adapted hormone indices, offer a successful alternative to previously published AVS analysis algorithms with lower radiation exposure compared to a full-FOV CACT.