A comparison of transcranial Doppler and magnetic resonance imaging for long term changes in middle cerebral artery stenosis

Abstract

Objectives: Intracranial arterial stenosis may progress or regress, of which the diagnosis is important to predict the risk of stroke or to evaluate the response of treatment. Transcranial Doppler (TCD) seems to be useful for this purpose, however, optimal diagnostic criteria have not been validated yet. Our study was designed to compare TCD changes with magnetic resonance angiography (MRA) to validate optimal TCD criteria for progression or regression of middle cerebral artery (MCA).

Patients and methods: We prospectively enrolled patients who visited our neurology department due to MCA stenosis on TCD examination. Brain MRA was used to identify patients with stenosis of the same site of MCA. Progression or regression was defined by change of MRA grading (normal, mild, moderate, severe or occlusion). Various criteria of mean flow velocity (MFV) difference and percent change were assessed. To register more patients for reliable analysis, additional patients with the same inclusion criteria were recruited retrospectively. All patients enrolled in the study were symptomatic or asymptomatic atherosclerotic MCA stenosis.

Results: Eighteen patients were enrolled and 21 MCAs with completed follow-up TCD and MRA were analyzed (mean age 68.4 years, mean follow-up 17.8 months). In addition, 40 MCAs from 30 retrospective patients were also analyzed (mean age 65.7 years, mean follow-up 22.3 months). Among assessed criteria, the most optimal cutoff value for the progression of stenosis was 20 cm/s, at which the sensitivity and specificity were 100% and 91% in prospective group, and were 80% and 93% in retrospective group. In the % difference analysis, prospective group showed sensitivity 100% and specificity 82% in the 20% cutoff. The retrospective group showed sensitivity 80% and specificity 93% in the 15% cutoff. However, results of the regression group were not consistent.

Conclusions: Diagnosis of progression of MCA stenosis with serial TCD examination is feasible and MFV change of 20 cm/s and % change of 15-20% are suggested as optimal cut-off value but not in the regression. These criteria would be useful for the clinical research and real-world practice.

Keywords: Arterial stenosis; Blood flow velocity; Magnetic resonance imaging; Middle cerebral artery; Progression; Transcranial Doppler.