Diagnostic Accuracy of Transcranial Doppler for Detection of the Proximal Middle Cerebral Artery Stenosis

Abstract

Abstract-Background and Purpose : Although several studies regarding the diagnostic value of transcranial Doppler ultrasonography (TCD) for detection of middle cerebral artery stem (M1) stenosis have been published, most studies have been limited to whites and used different TCD parameters. We aimed to evaluate the diagnostic accuracy of TCD in detecting M1 stenosis in Koreans when various flow velocity criteria were applied. Subjects and Methods : We studied 30 patients (25 men and 5 women, age = 48.2±15.9 years) who underwent both TCD and conventional cerebral angiograpy. TCD findings of 24 stenotic M1 segments demonstrated by cerebral angiography were reviewed and compared with those of 28 normal M1 segments. In addition to mean velocity (MV), pulsatility index (PI) and pulsatility transmission index (PTI) of M1, the following velocity parameters were measured: MVs of the anterior (ACA) and posterior cerebral arteries (PCA), ACA/M1 and PCA/M1 velocity ratios, and ACA velocities ratio (ACAVR). Results : PI and PTI of stenotic M1 segments were significantly lower than those of normal M1 segments (p < 0.05). Sensitivity, specificity, and diagnostic accuracy of TCD were 83.3%, 85.7%, and 84.6% when an MV cutoff of ≥ 80 cm/sec was used as the criteria for M1 stenosis, and 75%, 96.4%, and 86.5% when a cutoff of ≥ 90 cm/sec was used. False-negative cases, whose MV was < 80 cm/sec, were exclusively associated with very severe M1 stenosis in cerebral angiography. Their TCD findings showed increased ACA/M1 or PCA/M1 ratios, or ACAVR, probably indicating collateral pathways. Conclusions : TCD is very useful for the detection of M1 stenosis except for very severe one. MV criteria (≥ 90 cm/sec) alone can be very specific, and various arterial velocity ratios may enhance the diagnostic sensitivity of TCD. Korean Journal of Stroke 1999;1(2): 192~196