Contrast-enhanced transcranial color-coded real-time sonography: a reliable tool for the diagnosis of middle cerebral artery trunk occlusion in patients with insufficient temporal bone window.

Abstract

To the Editor: Baumgartner et al1 recently reported on the diagnostic value of contrast-enhanced transcranial color-coded duplex sonography (CE-TCCS) in ischemic cerebrovascular disease. In this study, 33 patients with insufficient temporal insonation conditions (21 patients had ischemic stroke and 12 suffered from transient ischemic attack) were investigated after application of a galactose-based echo contrast agent. The presence of an insufficient temporal bone window was indicated when two sonographers estimated that they were unable to evaluate the basal cerebral arteries by means of color and spectral Doppler imaging in unenhanced examinations. After application of a galactose-based echo contrast agent, 66% of the CE-TCCS examinations were considered conclusive. Cross-flow through the anterior and posterior communicating arteries due to extracranial occlusive disease could be demonstrated in 3 and 2 patients, respectively. No stenoses or occlusions of intracranial arteries could be visualized. We would like to add our CE-TCCS experiences in severely affected stroke individuals with insufficient acoustic bone windows (IABW). 30 patients (17 women and 13 men; mean age, 75.2 [range, 59 to 86] years) with IABW and severe cerebrovascular event (European Stroke Scale score of <35 points) suggestive of middle cerebral artery (MCA) trunk occlusion were examined after injection of 9 ml of 400mg/ml echo-contrast agent (Levovist; Schering AG). The temporal bone window was considered absent if no vascular structure could be detected in unenhanced TCCS images. Occlusion of the MCA was diagnosed if the following criteria were met: (1 ) discontinuous or missing color-coded signal of the MCA main stem, (2 ) visualization of at least one other ipsilateral artery (anterior cerebral artery or posterior cerebral artery), and (3 ) identification of the MCA on the contralateral side. For comparison with CE-TCCS scans, at least one angiographic study (digital angiography, MR angiography, or spiral CT angiography) was performed within 12 …