Background and purpose: Although the hyperattenuated middle cerebral artery sign is known to be related to acute infarction, the volume of clot associated with it is not known. We investigated whether the presence or absence of hyperattenuated artery sign (HAS) on noncontrast CT (NCCT) can predict the thrombus volume.
Materials and methods: We enrolled 90 consecutive patients with acute infarction who underwent both 5- and 1.25-mm NCCT and CT angiography (CTA). HAS was determined on 5-mm NCCT retrospectively. According to the location of thrombi, the patients were classified into ICA (ICA terminus/ICA and others), M1 (M1/both M1 and M2), and M2 (M2) groups. Thrombus volumes were measured by 1.25-mm NCCT and were compared between patients with and without HAS.
Results: Occlusion of major arteries was seen on CTA in 78 patients. HAS was found in 46 patients (59.0%). The mean thrombus volume was significantly larger in patients with HAS than in those without except for the M2 group (ICA group: [n = 14], 188.7 +/- 122.5 mm(3) versus 39.4 +/- 12.1 mm(3) [P = .022]; M1 group: [n = 42], 128.1 +/- 119.2 versus 56.8 +/- 32.5 [P = .005]; M2 group: [n = 22], 34.7 +/- 32.2 versus 20.0 +/- 20.0 [P = .18]). Thrombus volumes determined by receiver operating characteristic curve analysis were 52.36 mm(3) in the ICA group (sensitivity, 90.9%; specificity, 100%) and 53.96 mm(3) in the M1 group (sensitivity, 88.0%; specificity, 58.8%).
Conclusion: Thrombus volumes were significantly larger in patients with HAS than in those without in ICA and M1 occlusions. The detection of HAS may provide an idea concerning rapid and dichotomized estimation of thrombus volume, which may be helpful for treatment decisions in potential candidates for thrombolysis.