Carotid web: An occult mechanism of embolic stroke

The carotid web is a proposed stroke mechanism that may underlie cryptogenic stroke, particularly in younger patients without vascular risk factors. The web appears as a shelf-like projection into the lumen of the proximal cervical internal carotid artery without evidence of calcification. It is pathologically defined as intimal fibromuscular dysplasia. Altered haemodynamics distal to the web cause flow stagnation and remote embolisation of fibrin-based clots. It is best demonstrated and diagnosed on CT angiography (CTA) of the neck because of its ability to resolve calcium and create multiplanar reconstructions. Although they can be readily visualised on CTA, carotid webs may be missed or misinterpreted because they do not typically cause haemodynamically significant stenosis and can mimic arterial dissection, non-calcified atherosclerotic plaque and intraluminal thrombus. Options for management include antiplatelet therapy, carotid endarterectomy and carotid artery stenting. Modern management strategies for cryptogenic stroke include long-Term cardiac monitoring, further investigation for structural cardiac disease and a diagnostic workup for arterial hypercoagulability, however, these strategies are not likely to capture the possibility of a carotid web. Carotid webs should be suspected in a young patient presenting with recurrent unihemispheric strokes particularly when conventional vascular risk factors are not present

Emergence of Venous Stenosis as the Dominant Cause of Pulsatile Tinnitus

Background The role of arteriovenous shunts such as dural fistulas, arterial steno‐occlusive states, anatomic variants, and hypervascular tumors in the genesis of pulsatile tinnitus (PT) has long been recognized. On the venous side, diverticula, high‐riding jugular bulb, and sinus wall dehiscence have also been implicated. However, the overall most common cause—venous sinus stenosis (VSS)—continues to be underrecognized. Its clinical importance, separate from venous stenosis association with intracranial hypertension, also requires emphasis. Methods A retrospective review of the last consecutive 208 cases of PT seen at our institution was performed and cause determined, when possible, based on clinical and radiographic data. Results VSS was the common cause of PT (34% of overall cohort). Over 90% are women. Typical clinical presentation was a unilateral whoosh‐like sound in sync with heartbeat that could be completely or nearly completely abolished by ipsilateral jugular compression. This clinical scenario virtually guaranteed the presence of VSS, with very high sensitivity, specificity, positive, and negative predictive values. About two thirds of patients with VSS also harbored other venous anatomic variations such as a high‐riding jugular bulb or sinus diverticulum, that should not be misinterpreted as the primary cause of PT. Most did not have signs or symptoms of intracranial hypertension, even though cerebrospinal fluid and venous pressures are frequently elevated. Conclusions VSS appears to be the most common identifiable cause of PT. Judicious attention to this finding can be immensely helpful in prompt and accurate diagnosis

Sonolucent cranioplasty in extracranial to intracranial bypass surgery: Early multicenter experience of 44 cases

Background: The new sonolucent cranioplasty implant (clear polymethyl methacrylate, PMMA) adds functionality besides surgical reconstruction. One possible application uses the transcranioplasty ultrasound (TCUS) technique after PMMA cranioplasty to assess graft patency of extracranial-intracranial (EC-IC) bypass procedures. Objective: To report our early multicenter experience. Methods: This is a multicenter analysis of consecutive EC-IC bypass patients from 5 US centers (2019-2022) with closure postbypass using PMMA implant. Results: Forty-four patients (median age 53 years, 68.2% females) were included. The most common indication for bypass was Moyamoya disease/syndrome (77.3%), and superficial temporal artery to middle cerebral artery bypass was the most common procedure (79.5%). Pretreatment modified Rankin Scales of 0 and 1 to 2 were noted in 11.4% and 59.1% of patients, respectively. Intraoperative imaging for bypass patency involved a combination of modalities; Doppler was the most used modality (90.9%) followed by indocyanine green and catheter angiography (86.4% and 61.4%, respectively). Qualitative TCUS assessment of graft patency was feasible in all cases. Postoperative inpatient TCUS confirmation of bypass patency was recorded in 56.8% of the cases, and outpatient TCUS surveillance was recorded in 47.7%. There were no cases of bypass failure necessitating retreatment. Similarly, no implant-related complications were encountered in the cohort. Major complications requiring additional surgery occurred in 2 patients (4.6%) including epidural hematoma requiring evacuation (2.3%) and postoperative surgical site infection (2.3%) that was believed to be unrelated to the implant. Conclusion: This multicenter study supports safety and feasibility of using sonolucent PMMA implant in EC-IC bypass surgery with the goal of monitoring bypass patency using TCUS