Quantification of Subarachnoid Hemorrhage by Three-Dimensional Computed Tomography: Correlation Between Hematoma Volume and Symptomatic Vasospasm

Abstract

Subarachnoid hemorrhage (SAH) volume was measured by three-dimensional computed tomography (3D-CT) and the correlation examined between the SAH volume and the occurrence of symptomatic vasospasm (SVS). Experimental (in vitro) hematomas were made with blood obtained from 10 volunteers. The hematoma volume was determined by actual measurements and by 3D-CT using a CT number in the range of 40-80 Hounsfield units (HU) on days 1, 4, 7, 11, and 14. The coefficients on days 1 and 4 were relatively high and the correlation between measured and estimated volumes was significant on days 7, 11, and 14. 3D-CT was also performed in 50 patients with SAH at onset (day 0) and on days 1, 4, 7, and 14. The hematoma volume including the volume of normal structures was automatically calculated (V1). The volume of normal structures (V2) with CT numbers of 40-80 HU was calculated in another 50 patients without intracranial lesions as 12 ml. The total hematoma volume was defined as V1 minus mean V2. The mean SAH volume was 44, 36, 21, 11, and 8 ml on days 0, 1, 4, 7, and 14, respectively. The hematoma volumes were significantly larger in patients with SVS than in patients without SVS at all time points. The minimum hematoma volume in patients with SVS was 92, 76, 42, 24, and 12 ml on days 0, 1, 4, 7, and 14, respectively. This method allows the quantitative determination of SAH volume based on 3D-CT, and may be useful in clinical studies of cerebral vasospasm.

Automatic Quantification of Subarachnoid Hemorrhage on Noncontrast CT

“…Sato et al 23 proposed an automated measurement on 3D CT to quantify SAH on the basis of thresholding between 40 and 80 HU, which could rapidly measure SAH volume. However, the time needed to manually exclude the scalp and subcutaneous tissue was not taken into account.…”

“…A quantitative volume and density measurement may reduce interobserver variability in comparison with current scales and would provide physicians with a potentially valuable tool for outcome prediction and treatment guidance. 23 As such, the aim of this study was to design and validate a reliable and easy-to-apply automatic measurement for subarachnoid hemorrhage quantification.…”

Volumetric analysis of subarachnoid hemorrhage: assessment of the reliability of two computerized methods and their comparison with other radiographic scales

“…More recently, Ko et al 14 used personal computer-based software to quantify volumes in DICOM images, and showed that the quantitation of SAH is feasible, and that both cisternal and total bleeding volume are related to both the development of DCI and outcome. Sato et al 29 developed a method to quantify SAH on 3D CT, which yields volume data in less time than with 2D techniques. In this method, hemorrhage volume within the different compartments is determined based on blood Hounsfield units.…”