Coronary artery stenosis in moyamoya disease: tissue characterization by 256-slice multi-detector CT and virtual histology.

A 20-year-old Korean man presented with a 3-week history of exertional chest pain to our cardiology outpatient clinic. He had been diagnosed with Moyamoya disease at the age of 5 years and had undergone bilateral extracra-nial-intracranial bypass surgery. His last magnetic resonance angiogram confirmed Moyamoya disease and revealed a good neovascularization of the both external carotid arteries. He had stage I hypertension but did not receive any antihypertensive medication. He denied having diabetes mellitus, dyslipidemia, tobacco use, or any family history of early atherosclerotic coronary artery disease. A treadmill exercise test demonstrated 3-mm ST-segment elevation in leads V2, V3, V4 and II, III, aVF in stage III (Figure 1). A coronary computed tomography angiogra-phy using a 256-slice multi-detector computed tomography scanner (Brilliance iCT; Philips Medical Systems, Best, The Netherlands) showed moderate to severe discrete stenosis in the proximal left anterior descending artery (LAD) with a noncalcified plaque (Figure 2A–2C) and a mean Hounsfield Units of 87.5, indicating a fibrous plaque. The reconstructed image using dedicated automated plaque analysis software (Extended Brilliance Workspace V4.0; Philips Healthcare, Cleveland, OH) also showed an isolated noncalcified plaque in the proximal LAD (Figure 2D) and an eccentric fibrous plaque (Figure 2E). A coronary angiogram revealed critical stenosis in the prox-imal LAD, whereas the remaining coronary artery segments seemed to be normal (Figure 3A). We performed intravas-cular ultrasound and virtual histology (VH) of the proximal LAD lesion (IVUS VH; Volcano Corp, Rancho Cordoba, CA). A grey-scale intravascular ultrasound image showed homogenous, eccentric, echogenic intimal thickening of the proximal LAD (Figure 4A, Movie I in the online-only Data Supplement). The mid and distal LAD showed no pathological intimal thickening. In detailed analysis of plaque composition by the VH, this thickened intima was mainly composed of fibrous tissue (dark green area in a reconstructed color-coded tissue map, 79% of the plaque) with minimal lipid pooling , but without any calcium deposition (Figure 4B). With regard to coronary stenosis, a drug-eluting stent was successfully implanted (3.0×18 mm Endeavor Resolute, Medtronic Inc., New York, NY). The final angiogram showed minimal residual stenosis (Figure 3B). The patient has been free from angina after the coronary intervention. A few cases of coronary artery stenoses in patients with Moyamoya disease have been reported. The histopathology of these coronary lesions showed a homogenous, soft inti-mal proliferation with minimum lipid deposition and without substantial inflammatory cell infiltration. It is similar to the findings of the …