Departments of Neurosurgery 1, Cardiology 2, Radiology 3, Gifu University Graduate School of Medicine, Gifu, Japan. Kiyofumi Yamada 1, Shinichi Yoshimura 1, Masanori Kawasaki 2, Yukiko Enomoto 1, Takahiko Asano 3, Shinya Minatoguchi 2, Toru Iwama 1 Evaluation of high risk plaques by magnetic resonance imaging can improve the outcomes of carotid artery stenting and carotid endarterectomy

Background Unstable carotid plaques are associated with an increased incidence of embolic complications after Carotid artery stenting (CAS) or Carotid endarterectomy (CEA).

The purpose of this study was to elucidate the relationship between the tissue characteristics of plaques using magnetic resonance imaging (MRI) and the incidence of new ipsilateral ischemic lesions detected by diffusion weighted imaging (DW)-MRI after CAS and CEA. Objective

Materials & Methods Carotid artery stenosis (Symptomatic; >50%) (Asymptomatic; >80%) n=81 CEA n=25 CAS n=56 Plaque imaging by MRI DW-MRI

Plaque imaging by MRI T1 weighted image of Black – Blood MRI (BB-MRI) Philips Intera Achieva Nova Dual 1.5 T Standard neck array coil Cardiac gated, Double inversion recovery- 2DTSE under SPIR TR / TE; 1 x R-R interval / 10ms TSE; factor 7, Matrix; 256 x 80% (recon 512) Scan time; 1min 13sec Yamada K et al, Cerebrovasc Dis 2009 Yamada K et al, Atherosclerosis 2010

Plaque imaging by MRI plaque SCM Sternocleidomastod muscle Yamada K et al, Cerebrovasc Dis 2009 Yamada K et al, Atherosclerosis 2010 Signal intensity ratio (SIR) Plaque signal intensity SCM signal intensity SIR =

SIR ≧ 1.25: High SIR plaque SIR ＜ 1.25: Low SIR plaque Plaque imaging by MRI

SIR ≧ 1.25 (T1WI of BB-MRI) ・ Lipid & Hemorrhage ≧ 50% ・ Higher incidence of new ischemic lesions after CAS Plaque imaging by MRI Yoshida K et al, AJNR Am J Neuroradiol 2008 Yamada K et al, Atherosclerosis 2010 High risk plaque of distal embolism

New ischemic lesions detected by DW-MRI Schluter M et al, J Am Coll Cardiol 2003 Pinero P et al, AJNR Am J Neuroradiol 2006 Yamada K et al, Atherosclerosis 2010

CAS procedures ・ Two kinds of antiplatelet drugs for more than 7 days before CAS. ・ Distal embolic protection devices Balloon : n = 49 Filter : n = 7 ・ Stent Precise : n = 46 Wallstent : n =10

CEA procedures

Case 1 : CAS for high SIR plaques BB-MRI SIR: 1.37 Pre Post

DW-MRI Multiple ischemic lesions

Case 2 : CEA for high SIR plaques Pre Post BB-MRI SIR: 1.68 Azan Glycophorin A

DW-MRI No ischemic lesion

High SIR plaque group (n = 43) 17/28 61% 2/15 13% CAS CEA P = Results 1: New ischemic lesions Patient rate of new ischemic lesions (%)

6/28 21% 0/10 0% CAS CEA NS Patient rate of new ischemic lesions (%) Low SIR plaque group (n = 38)

Results 2: Neurological complications CAS: n = 28 2 minor stroke (7.1%) No complication CEA: n = 15 High SIR plaque group (n = 43)

CAS: n = 28CEA: n = 10 No neurological complication Low SIR plaque group (n = 38)

Summary of results ・ In the patients with high SIR plaques for CAS, there were higher incidence of distal embolism than CEA. ・ In the patients with low SIR plaques, the incidence of distal embolism were not different between both procedures.

Treatments for high risk plaques 1. CEA 2. CEA high risk → CAS with other protection devices (Proximal protection device) 3. CEA or CAS after plaque stabilization by drugs. (statins)

Conclusions It is recommended that plaque components be evaluated by BB-MRI, and CEA should be selected when the SIR measured by BB- MRI is ≧ 1.25.