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Correspondence to Dr Michael J Alexander, Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; [email protected]
Introduction
The management of intracranial atherosclerotic disease (ICAD) has been evolving with advanced imaging, refinements of best medical treatment, and the development of endovascular options. There has been a significant increase in the use of endovascular therapy for symptomatic ICAD in the USA over the most recent 6 years of data in the National Inpatient Sample (NIS) database.1 The number of stenting procedures for ICAD in 2020 was fivefold higher than the number of stenting procedures performed in 2014. The rationale for this review is to update neurointerventionalists in these areas so that evidence-based decisions can be considered when counseling potential patients regarding their risks, benefits, and potential complications. We will review imaging options of digital subtraction angiography (DSA), CT angiography (CTA), CT perfusion (CTP), high-resolution MR vessel wall imaging (HR-VWI), quantitative MR angiography (qMRA), optical coherence tomography (OCT), intravascular ultrasound (IVUS), and fractional flow reserve (FFR) assessment and how these may impact management decisions.
The seminal studies of medical treatment for ICAD will be reviewed with respect to patient subgroups and how these are influencing ongoing medical therapy trials. We will analyze endovascular considerations, including patient selection, timing of procedure, medical treatment issues, and periprocedural management. We will review the options of angioplasty alone versus angioplasty with stenting, and discuss options of balloon types (standard vs drug-coated) and stents (bare metal, polymer-coated, and drug-eluting; balloon expandable vs self-expanding, open cell vs closed cell design). Finally, we will review preliminary data on the use of rescue stenting or performing angioplasty and/or stenting for failed thrombectomy in patients with large vessel occlusive acute ischemic stroke (AIS) with underlying ICAD.
Diagnosis of ICAD
DSA is the gold standard for assessing the severity of stenosis in ICAD and angiographic collaterals. However, DSA alone does not assess cholesterol plaque characteristics, circumferential nature of plaque, and potential inflammatory changes of intracranial arterial stenosis.
MR intracranial vascular imaging is a valuable non-invasive diagnostic tool, but the sensitivity depends on the type of MR imaging. Time of flight (TOF) MRA typically has less sensitivity than other modalities. In highly stenotic lesions, there is an overestimation of stenosis in TOF due to loss of local blood...