The forgotten side: in vivo assessment of inflammatory atheroma burden on the contralateral side to symptomatic carotid stenosis using high resolution USPIO-enhanced MR imaging
Howarth S, Tang T, Joubert I, Gillard J, Brown A, Kirkpatrick P, Gaunt M, Graves M
University of Cambridge, Addenbrooke's NHS Trust
It is well known that vulnerable atheromatous plaque has a thin, fibrous cap and large lipid core with associated inflammation which can be detected on USPIO-enhanced MR imaging. Studies using USPIO to assess macrophage burden in symptomatic carotid disease have not yet analyzed the contralateral asymptomatic side.20 symptomatic patients underwent multi-sequence imaging at 1.5 Tesla pre and 36 hours post USPIO infusion. Images were manually segmented into quadrants and signal change in each quadrant was calculated following USPIO. Contra-laterally there were 153 quadrants (54%) with a signal drop post USPIO when compared with 201 quadrants (73%) on the symptomatic side. This suggests that investigation of the contralateral side in patients with symptomatic carotid stenosis can demonstrate inflammation in over 50% of plaques, despite a mean stenosis of only 46%. Patients with symptomatic carotid disease having had an endarterectomy should have their contralateral carotid artery followed up.