Hyperintense Plaque With Noncontrast T1-Weighted Magnetic Resonance Coronary Plaque Imaging Leading to Acute Coronary Syndrome

Abstract

A 73-year-old diabetic man underwent multislice computed tomography (MSCT) and noncontrast T1-weighted (T1W) magnetic resonance imaging (MRI) for the evaluation of atypical chest discomfort after an exercise ECG was nondiagnostic. The MSCT demonstrated a low-density positive remodeling plaque and spotty calcification without significant stenosis in the proximal segment of the right coronary artery ( Figure 1A and 1B). Noncontrast T1W MRI, using a 1.5-T MR system (Intera, Philips Medical Systems, Best, the Netherlands), revealed a hyperintense plaque (HIP) in the right coronary artery in an area corresponding to the plaque visualized by MSCT ( Figure 1C and 1D). With clear evidence of atherosclerotic disease, the patient was given glimepiride and voglibose with recommendations for strict diet therapy for treatment of diabetes mellitus; he continued to take aspirin. One year after these examinations, the patient presented with sudden-onset crushing chest pain at our emergency room. Despite the modifications to his medications, his coronary risk factors had not improved (hemoglobin A 1c , 7.1-6.4%, low-density lipoprotein cholesterol, 124 -110 mg/dL; high-density lipoprotein cholesterol, 34 -32 mg/dL). On admission, an ECG showed ST-segment elevation in leads II, III, and aV F . Emergent coronary angiography revealed an obstructive lesion in the proximal segment of the right coronary artery in a region corresponding to the HIP previously identified by MRI (Figure 2A). Intravascular ultrasound confirmed extensive attenuation ( Figure 2B) at that segment, and a bare metal stent was successfully implanted with a distal protection device. After stent implantation, a large amount of debris was collected.Recently, Kawasaki et al 1 reported that the presence of HIP on noncontrast T1W MRI is associated with positive coronary remodeling, low CT density, and ultrasound attenuation by MSCT or intravascular ultrasound. However, it is unknown whether HIP has a greater potential for plaque rupture and subsequent acute coronary syndrome. To our knowledge, Figure 1. Multislice computed tomography (A, curved multiplanar reconstruction; B, horizontal) demonstrates low-density plaque (Ϫ36 Hounsfield units, remodeling index 1.6, arrowheads) with spotty calcification (arrow) in the proximal segment of the right coronary artery. On the corresponding noncontrast T1-weighted magnetic resonance imaging (C, oblique image; D, horizontal), this low-density plaque was visualized as a hyperintense lesion (arrowheads). Figure 2.Right coronary angiography revealed an occlusion of the proximal segment of the right coronary artery (A). On intravascular ultrasound examination (B), a near-circumferential attenuation (arrowheads) was observed at the culprit lesion, corresponding with the plaque observed both by multislice computed tomography and by noncontrast T1-weighted magnetic resonance imaging.

Prediction of Acute Coronary Syndrome by Using Multislice Computed Tomography

“…These HIPs have been observed more frequently in the culprit lesions of ACS patients. 23, 24 In addition, Oei et al reported that these HIPs may correlate with intraplaque hemorrhage and they concluded that this plaque imaging technique may emerge as a valuable tool for detecting "active coronary lesions". 25 On the basis of its ability to provide excellent soft-tissue contrast, MRI appears to be the superior modality for characterizing unstable plaque components.…”

Noninvasive detection of coronary artery wall thickening with age in healthy subjects using high resolution MRI with beat‐to‐beat respiratory motion correction

“…The 3D spiral acquisitions with dark blood preparation used to acquire the coronary vessel wall images in this study were proton density weighted and provided no characterization of vessel wall composition. However, several recent studies have partly addressed this (26–29) by performing T1‐weighted imaging pre‐ and postadministration of gadolinium based contrast agent. These additional acquisitions could also be performed with 3D spiral imaging with B2B‐RMC at high respiratory efficiency after only minor modifications to the sequence used here.…”

Noninvasive Coronary Plaque Imaging

“…The presence of a HIP in the carotid arteries predicted cardiac events, outperforming carotid intimal medial thickness and traditional cardiovascular risk factors 60 ) . In the coronary arteries, a case report first described a high-intensity coronary plaque going on to rupture and cause MI 61 ) . HIPs are quantitatively assessed by a plaque-tomyocardium signal intensity ratio (PMR).…”