Discrepancy Between Duplex Sonography and Digital Subtraction Angiography When Investigating Extra- and Intracranial Ulcerated Plaque

Noninvasive color-coded duplex sonography has become a good, convenient, and reproducible screening tool for the general population when studying cerebral hemodynamics and atherosclerotic disease. Digital subtraction angiography (DSA) is still the gold standard for the diagnosis of carotid stenosis, although other noninvasive imaging tools are also available. At present, ultrasound scanning, followed by confirmatory DSA, is a cost-effective way to survey patients suspected of suffering from cerebral arterial stenosis. We report two patients who had cerebral ischemic symptoms due to high-grade stenosis of either the cervical internal carotid artery (ICA) or the middle cerebral artery (MCA), combined with an ulcerated plaque. Ultrasonographic Doppler analysis identified high-grade stenotic lesions as marked elevations in the turbulent flow of the cervical ICA in one patient and of the middle cerebral artery in the other patient. Subsequently, huge plaque ulceration was found by color B-mode scanning of the patient with cervical ICA stenosis. However, DSA was able to demonstrate only a mild–moderate degree of stenosis associated with the lesions. High-grade stenotic lesions of the ICA and the middle cerebral artery were reconfirmed by computed tomography angiography and magnetic resonance angiography. An atheromatous plaque with ulceration is believed to be the cause of this discrepancy between ultrasonography and DSA.