In an attempt to evaluate the relationship of M1-M2 blood flow velocity to symptomatic vasospasm in the M1-M2 region, transcranial color-coded duplex sonography (TCCS) was performed on patients undergoing craniotomy for anterior circulation aneurysm neck clipping before day 2. During the period from September 2001 to Februarr 2004, TCCS was carried out on 27 SAH patients, who were assigned Hunt & Hess grades 1 to 3. There were 5 men and 16 women, ranging in age from 40 to 81 years (mean 60 years). M2 was identified in 21 patients (77%) by TCCS, and two branches of M2 were identifiable in only 10 of them. Five female patients, aged 51 to 57 years, had symptomatic vasospasm of M2 branches during days 6 to 10. Their Hunt&Hess grades were 2 in four patients and 3 in one. One had a middle cerebral artery aneurysm, 2 had internal carotid-posterior communicating artery aneurysms, and 2 had anterior communicating artery aneurysms. At symptomatic vasospasm their mean peak systolic (PSV) and mean flow velocities (Vm) of M2 were 176±17.3 and 132.6±17.9 cm⁄s, respectively. These were significantly higher than in the other 16 patients without symptomatic vasospasm (PSV: 109.6±109.6±8.5, Vm: 66.9±6.9±5.4 cm⁄s, respectively, p‹0.05). Two patients had M2 vasospasm only, and their PSV and Vm of M2 were higher than those of M1. TCCS is a useful examination for monitoring vasospasm of M2 after SAH. If PSV and Vm of M2 are higher than those of M1, vasospasm of M2 is highly likely.
