Usefulness of the low tube voltage scan in the head CT-angiography with the subarachnoid hemorrhage

Abstract

PURPOSE: Head computed tomography-angiography (CTA) is useful for the diagnosis of subarachnoid hemorrhage. Adequate cerebrovascular CT value is essential for obtaining a good quality CTA. Low tube-voltage scan is considered useful for CTA; however, reduction in tube voltage increases the image noise. In this study, we verified the utility of low tube-voltage scan for head CTA for diagnosing subarachnoid hemorrhage.
METHODS: We scanned a head phantom (Kyoto Kagaku Corporation, Japan) using a tube voltage of 80, 100, and 120 kv. The tube current used was 450, 360, and 300 mA, respectively. The vascular CT value, contrast to noise ratio (CNR), and Computed Tomography Dose Index volume (CTDIvol) were calculated for each set of parameters. In addition, we measured the CT value, CNR, contrast media arrival time than a clinical images.
RESULTS: The vascular CT value increased with decrease in tube voltage. At equivalent radiation dose, 80kv scan was associated with the highest CNR.
CONCLUSION: Low tube-voltage scan is thus useful for head CTA for detecting subarachnoid hemorrhage that a condition of the patients are severe.