Subtracted 3D CT angiography for the evaluation of intracranial aneurysms in 256-slice multidetector CT: usefulness of the 80-kVp plus compact contrast medium bolus protocol

To evaluate the usefulness of an 80-kVp and compact contrast material protocol for arterial phase subtracted cerebral 3D-CTA using 256-slice multidetector CT. Thirty-two patients underwent CT with 100 kVp and received a contrast dose of 370 mgI/kg body weight over 15 s (protocol A). Thirty-three patients underwent CT with 100 kVp and received a contrast dose of 296 mgI/kg body weight over 10 s (protocol B). Thirty-three other patients underwent CT with 80 kVp and received a contrast medium dose of 296 mgI/kg body weight over 10 s (protocol C). We compared the arterial attenuation and contrast noise ratio (CNR) of each protocol. Two independent readers assessed overall image quality. Arterial attenuation was significantly higher under protocols A (418.6 +/- 71.1 HU) and C (442.7 +/- 79.3 HU) than under protocol B (355.8 +/- 107.2 HU; P < 0.05). The CNR of protocol C (26.1 +/- 6.1) was higher than that of protocol A (20.7 +/- 8.4; P < 0.05). The overall image quality of protocol A was higher than that of protocol C (P < 0.01). The 80-kVp plus compact contrast protocol is well suited to arterial phase subtracted cerebral 3D-CTA without confounding venous enhancement. aEuro cent Subtracted 3D CT angiography is useful in the evaluation of intracranial aneurysms. aEuro cent A compact contrast material protocol increased arterial attenuation without venous contamination. aEuro cent Low-kVp CT compensated for the decreased amount of contrast medium. aEuro cent An 80-kVp CT with a compact enhancement bolus provides good intracranial 3D-CT angiography.