title: Relationship between tissue characterization with 40 MHz intravascular ultrasound imaging and 64-slice computed tomography.
abstract: BACKGROUND
  Identification of coronary plaque composition is important for selecting the treatment strategy, and 64-slice computed tomography (CT) is a noninvasive method of characterizing atherosclerotic plaques. However, the correlation between plaque characteristics detected by CT and intravascular ultrasound (IVUS) is not clear. A 40 MHz IVUS imaging system (iMap-IVUS) has recently been developed to evaluate plaque composition. The aim of this study was to compare iMap-IVUS with 64-slice CT angiography for the characterization of non-calcified coronary plaques.
  
  
  RESULTS
  Both 64-slice CT angiography and iMap-IVUS were performed in 19 patients (38 plaques). CT values were measured as Hounsfield units (HU) in circular regions of interest (ROI) drawn on the plaques. The iMap-IVUS system analyzed coronary plaques as fibrotic, lipidic, necrotic, or calcified tissue based on the radiofrequency spectrum. A positive correlation was found between CT values and the percentage of fibrotic plaque (r=0.34, p=0.036) or calcified plaque (r=0.40, p=0.011). Conversely, a negative correlation was found between CT values and the percentage of lipidic plaque (r=-0.41, p=0.01), or necrotic plaque (r=-0.41, p=0.01).
  
  
  CONCLUSIONS
  Good correlations were observed between the characteristics of non-calcified plaque determined by iMap-IVUS and the CT values of plaque detected by 64-slice CT scanning.
authors.affiliation: Division of Cardiovascular Medicine, Toho Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo, Japan. m-utsu0705@hotmail.co.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Utsunomiya
authors.forename: Hisao
authors.initials: H
authors.lastname: Hara
authors.forename: Masao
authors.initials: M
authors.lastname: Moroi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sugi
authors.forename: Masato
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D014057:Tomography, X-Ray Computed; D018084:Ultrasonography, Interventional