Comparison of Standard- and Low-Tube Voltage 320-Detector Row Volume CT Angiography in Detection of Intracranial Aneurysms with Digital Subtraction Angiography as Gold Standard

Rationale and Objectives The aim of this study was to prospectively assess the effect of low–tube voltage (80 kVp) 320–detector row volume computed tomographic (CT) angiography (L-VCTA) in the detection of intracranial aneurysms, with three-dimensional (3D) spin digital subtraction angiography (DSA) as the gold standard. Materials and Methods Forty-eight patients with clinically suspected subarachnoid hemorrhages were divided into two groups. One group underwent L-VCTA and DSA, while the other group underwent conventional–tube voltage (120 kVp) volume CT angiography (C-VCTA) and DSA. Vascular enhancement, image quality, detection accuracy of aneurysms, and radiation dose were compared between the two groups. Results For objective image quality, the L-VCTA group had higher mean vessel attenuation, correlated with higher image noise and lower signal-to-noise ratio, than the C-VCTA group. For subjective image quality, there were no significant differences between the two groups regarding scores for arterial enhancement, depiction of small arterial detail, interference of venous structures, and overall image quality scores. The mean effective dose for the L-VCTA group was significantly lower than for the C-VCTA group (0.56 ± 0.25 vs 1.84 ± 0.002 mSv), with a reduction of radiation dose of 69.73%. With 3D DSA as the reference standard, the sensitivity, specificity, and accuracy in the L-VCTA and C-VCTA groups were 94.12%, 100%, 94.4% and 100%, 100%, and 100%, respectively. In both groups, there were significant correlations for maximum aneurysm diameter measurements between volume CT angiography and 3D DSA; no statistical difference in the mean maximum diameter of each aneurysm was measured between volume CT angiography and 3D DSA. Conclusions L-VCTA is helpful in detecting intracranial aneurysms, with results similar to those of 3D DSA, but at a lower radiation dose than C-VCTA.