Evaluation of arteriovenous malformations (AVMs) with transcranial color-coded duplex sonography: does the location of an AVM influence its sonographic detection?

OBJECTIVE: The clinical value of transcranial color-coded duplex sonography (TCCS) in the evaluation of arteriovenous malformations (AVMs) has not yet been fully investigated. In this study, 54 intracranial AVMs confirmed by angiography were prospectively examined over 6 years. The purpose of the study was to describe their typical sonographic features and to define sensitivity for diagnosis with regard to the location of an AVM.
METHODS: Transcranial color-coded duplex sonographic findings for 54 patients with intracranial AVMs are presented. The vessels of the circle of Willis were identified by location, course, and direction of flow on color flow images.
RESULTS: In accordance with digital subtraction angiography, the intracranial AVMs could be visualized in 42 cases (sensitivity, 77.8%). The pathologic vessels were coded in different shades of blue and red, corresponding to varying blood flow directions in the AVM. The major feeding vessels could be easily identified. Hemodynamic parameters showing increased systolic and diastolic flow velocities and a decreased pulsatility index were better attainable with TCCS than with conventional transcranial Doppler sonography. Arteriovenus malformations located near the cortex, that is, in the parietal, frontal, occipital, and cerebellar regions of the brain, could not be visualized. In contrast, AVMs located in the basal regions were very easy to image (sensitivity, 88.9%). Additionally, TCCS proved useful for follow-up examinations postoperatively or after embolization.
CONCLUSIONS: Transcranial color-coded duplex sonography is a valuable noninvasive method for the diagnosis and long-term follow-up of intracranial AVMs. Arteriovenous malformations located in the axial imaging plane can be more easily detected. Nevertheless, TCCS should not be used as a screening method.