Microembolization Distal to a Basilar Artery Aneurysm Treated with Detachable Coils: A Case Study

Abstract

Introduction Since 1991, treatment of cerebral saccular aneurysms with coils by means of an endovascular approach has become increasingly used as an alternative to surgery. After this procedure, thromboembolic complications of stroke and transient ischemic attack, as well as silent embolic events seen on MRI, have been reported. The detection of microemboli (MES) in the cerebral circulation in a variety of conditions has been well established and has been observed in asymptomatic and symptomatic patients. We present a case of a 41-year-old man with subarachnoid hemorrhage (SAH) from a vertebrobasilar junction aneurysm treated with Guglielmi detachable coils. Multiple MES were detected in the basilar artery during serial transcranial Power M-mode Doppler (PMD) studies. A battery of tests was done to establish the source of embolization from the coiled aneurysm. Methods By use of conventional techniques, diagnostic TCD studies to determine the presence of vasospasm were performed using a Neuroguard Neuroflow (Medasonics, Freemont, CA). PMD, a new technique for the detection of emboli, was then performed using Spencer Technologies TCD100M (Seattle, WA). The TCD100M is a digital Doppler and displays Doppler power as intensity in an M-mode format. PMD signals are further colored red or blue according, to direction. MES are seen as high-power tracks in the PMD image as described by Moehring et al (Ultrasound Med Biol. 2002;28:49–57). Results Because of the possibility of multiple sources of embolization, our efforts were aimed at proving that the source of the embolization was the coiled aneurysm. Echocardiography, bubble studies, carotid duplex ultrasonography, and emboli monitoring of both middle cerebral and vertebral arteries did not show any MES. Power M-mode examination pointed to a depth of 85 mm in the basilar artery as the point where embolization began. This battery of tests strongly supports the presumptive origin and source of MES to be the coiled aneurysm of the vertebrobasilar junction. Conclusions Our case presentation demonstrates continuous silent microembolization from a previously coiled aneurysm. TCD has an important role in assessing patients with cerebral aneurysms for the detection of MES.