Intravascular Ultrasound in Carotid Web

Abstract

BackgroundCarotid web (CaW) is a shelf-like linear filling defect in the posterior aspect of the internal carotid bulb, representing an intimal variant of fibromuscular dysplasia. The diagnosis of CaW is traditionally restricted to digital subtraction angiography (DSA), CT/MR angiography (CTA/MRA), and Duplex ultrasonography. In this series of patients with acute ischemic stroke, we evaluated the potential utility of intravascular ultrasound (IVUS) in further characterizing suspected CaWs.MethodsThis is a case series of three patients with suspected CaW who underwent DSA for treatment or investigation of large vessel occlusion strokes. In all cases the stroke investigation failed to identify an alternative cause, and the stroke etiology was attributed to a symptomatic CaW. The procedure consisted of positioning a guide catheter in the common carotid artery, navigating the IVUS probe distal to the carotid bulb, and then retracting the probe with a manual pullback. The acquired images were then reviewed in an independent workstationResultsIn two of the three cases, IVUS showed an isoechoic-to-hyperechoic focal eccentric area at the posterior carotid bulb, consistent with CaW. The endoluminal protrusion was inconspicuous on IVUS due to the low resolution of ultrasound not allowing a clear differentiation between fibrosis, thrombosis, and atherosclerosis. No abnormalities commonly associated with atherosclerotic disease or dissections were noted. The CaW could not be depicted in the third patient.ConclusionThe use of IVUS in the diagnosis of CaW may have limited relevance. Continued investigation of other imaging modalities for accurate CaW diagnosis is recommended.

Use of intravascular optical coherence tomography to confirm the diagnosis of a carotid web in a patient with recurrent ipsilateral embolic strokes and evaluate the response to stenting

“…However, the 100–150 μm spatial resolution IVUS is insufficient for diagnosis of CaW, having recently failed to adequately differentiate between atherosclerosis, CaW, and thrombus. 3 OCT provides superior intravascular images with a 10-fold increase in spatial resolution (10–20 μm) resolution by measuring the reflection of near-infrared light. 7 The diagnostic accuracy of OCT has been validated through extensive histological analysis in human specimens.…”

Therapeutic and diagnostic targeting of fibrosis in metabolic, proliferative and viral disorders

“…Color-coding: the analysis of manuscripts described in section 4.1 revealed the frequency in which each organ and imaging modality are investigated and used for the detection of fibrosis in atherosclerosis and cardiac disease; light green = low frequency; green = medium frequency; dark green = high frequency. All images were adapted with permission [279,284,285,293,295]. [345,350,358,361,365,371,373].…”

“…Indeed, IVUS allowed for detection of carotid web protrusions, and was in agreement with the CTA and angiography scans. However, the low spatial resolution of IVUS does not provide further information about the physiological characteristics of the lesion, and cannot differentiate between fibrosis, thrombosis, and atherosclerosis [295] (Fig. 7c; image 10-12).…”

The carotid web: Current research status and imaging features

“…Contrast agent infusion delays and filling defects were observed using contrast-enhanced ultrasonography ( Zhou et al, 2022 ). Intravascular ultrasound provides a dynamic view of the vessel lumen using an ultrasonic mini-probe with a catheter technique, and the carotid web presents with a banding hypoechoic signal connecting to the vessel wall ( Hassani et al, 2020 ).…”