Middle Cerebral Artery Stenoses: Assessment by Magnetic Resonance Angiography and Transcranial Doppler Ultrasound

Abstract

Magnetic resonance angiography (MRA) findings of uni- or bilateral middle cerebral artery (MCA) stenosis were compared with results of transcranial Doppler ultrasound (TCD) and digital subtraction angiography (DSA). Eighteen patients with 22 MCA stenoses were selected by TCD criteria. To evaluate the diagnostic accuracy of MRA, TCD and DSA, criteria for classification of stenoses were established. MRA confirmed 21 MCA stenoses as revealed by TCD (n = 22). DSA did not demonstrate MCA stenoses in 6 cases diagnosed by TCD (classification grade I) and MRA. The classification of MCA stenoses by MRA correlated with TCD in 11 (50%) cases, while stenosis was underestimated by MRA in 3 (14%) and overestimated in 8 (36%) MCAs. Whereas the sensitivity of MRA for the detection of MCA stenoses compared to TCD and DSA findings was very high (100%), the correlation of the degree of stenosis by the three techniques was poor. This discordance is partly due to the insufficiency of routine DSA to reliably estimate the degree of stenosis since it delivers only one anterior-posterior projection plane. The combination of MRA and TCD is a noninvasive regime of high sensitivity to ensure the diagnosis of MCA stenosis and to estimate the severity of obstruction.