Assessment of Apparent Internal Carotid Occlusion on Ultrasound: Prospective Comparison of Contrast-enhanced Ultrasound, Magnetic Resonance Angiography and Digital Subtraction Angiography

a: DSA following left common carotid artery injection demonstrating a small stump of proximal ICA (arrow) with no demonstrable flow beyond it, indicating a proximal ICA occlusion. b: Surface shaded maximum-intensity projection CE-MRA of the left CCA, ICA and ECA, demonstrating a small stump of proximal ICA (arrow) with no demonstrable signal beyond it, indicating proximal ICA occlusion (same patient as Fig. 1a).

a: DSA immediately following left common carotid injection (left hand pane) with subsequent (middle pane) and delayed (right hand pane) images of the same region. There is a tight focal stenosis of the proximal ICA (arrow) with forward flow of contrast along a smooth walled distal ICA (arrowheads) beyond the stenosis. The delayed image shows contrast arriving at the siphon with no evidence of backfilling of unopacified blood from the other side. The left middle cerebral artery filled from the left CCA injection. This patient underwent CEA. b: Surface shaded maximum-intensity projection CE-MRA of the left CCA, ICA and ECA, demonstrating a tight proximal ICA stenosis within which there is no discernible signal (arrow) but with good filling of the ICA distal to this (arrowheads) up to the carotid siphon (same patient as Fig. 2a).