Accuracy of Color Duplex Ultrasound Diagnosis of Spontaneous Carotid Dissection Causing Ischemia

Abstract

Background and Purpose— Spontaneous dissection of the cervical internal carotid artery (sICAD) is mainly assessed with MRI and magnetic resonance angiography (MRA), which are not always at hand. In contrast, color duplex sonography (CDS) is readily available. We undertook this prospective study to examine the accuracy of CDS to diagnose sICAD in patients with first carotid territory ischemia. Methods— Consecutive patients with first carotid territory stroke or transient ischemic attack or retinal ischemia underwent clinical and laboratory examinations, ECG, CDS of the cerebral arteries, cranial computed tomography in case of stroke or transient ischemic attack, and echocardiography and 24-hour ECG in selected cases. Patients were included, if they were <65 years of age, CDS showed a probable sICAD (cervical internal carotid artery stenosed or occluded), or had no determined etiology of ischemia. All of the included patients underwent cervical MRI and MRA±cerebral catheter angiography. The sonographer was blinded to the results of MRI and angiography studies. Results— We included 177 of 1652 screened patients. Excluded patients (n=1475) were ≥65 years old (n=818), had another determined cause of ischemia (n=1475), and had intracranial hemorrhage (n=58). CDS diagnosed sICAD in 77 of 177 patients, and the etiology of ischemia was undetermined in the remaining 100 patients. Cervical MRI and angiography showed 74 sICAD; there were 6 falsely positive and 3 falsely negative CDS findings. Thus, sensitivity, specificity, and positive and negative predictive values for CDS diagnosis of patients with sICAD causing carotid territory ischemia was 96%, 94%, 92%, and 97%, respectively. Conclusions— Color duplex ultrasound allows the reliable exclusion of sICAD in patients with carotid territory ischemia, whereas diagnosis of CDS of sICAD must be confirmed with cervical MRI and MRA.