title: Comparison of near-infrared spectroscopy and optical coherence tomography for detection of lipid.
abstract: OBJECTIVE
  To compare intracoronary near-infrared spectroscopy (NIRS) and optical coherence tomography (OCT) for the detection of lipid, to identify NIRS signals to differentiate superficial lipid, and to characterize the plaque with yellow block (YB) chemograms on NIRS.
  
  
  BACKGROUND
  Intracoronary NIRS has been developed to detect lipid core plaque (LCP).
  
  
  METHODS
  We investigated a total of 17 patients who underwent both OCT and NIRS. NIRS analysis included plaque lipid core burden index (LCBI), LCP length, and the presence of YB on the block chemogram. OCT analysis included maximum lipid arc (LA), the length of lipid (LL), lipid index, and the thinnest fibrous cap thickness (FCT).
  
  
  RESULTS
  Twenty-five plaques with >40% plaque burden were analyzed. LCP, showing LCBI > 0, was observed in 20 plaques (80%) and YB was detected in seven plaques (28%). Plaque LCBI showed modest correlations with maximum LA and lipid index by OCT (r(2) = 0.319, P = 0.003 and r(2) = 0. 404, P = 0.001, respectively). Lipid length showed a significant correlation between NIRS and OCT measurements (r(2) = 0.581, P < 0.001). There was no significant difference in NIRS parameters between superficial and deep lipid. Plaques with YB compared with those without YB showed a larger LA, longer LL, and thinner FCT (185 ± 29° vs. 105 ± 76°, P = 0.014; 8.5 ± 3.3 mm vs. 3.3 ± 2.7 mm, P = 0.001; 112 ± 42 vs. 166 ± 61 µm, P = 0.033).
  
  
  CONCLUSIONS
  NIRS and OCT parameters showed modest linear correlations in the measurement of lipid. The accurate depth of lipid in the vessel wall could not be identified by quantitative NIRS parameters. YB chemograms represented more vulnerable features on OCT.
authors.affiliation: Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Taishi
authors.initials: T
authors.lastname: Yonetsu
authors.forename: William
authors.initials: W
authors.lastname: Suh
authors.forename: Farhad
authors.initials: F
authors.lastname: Abtahian
authors.forename: Koji
authors.initials: K
authors.lastname: Kato
authors.forename: Rocco
authors.initials: R
authors.lastname: Vergallo
authors.forename: Soo-Joong
authors.initials: SJ
authors.lastname: Kim
authors.forename: Haibo
authors.initials: H
authors.lastname: Jia
authors.forename: Iris
authors.initials: I
authors.lastname: McNulty
authors.forename: Hang
authors.initials: H
authors.lastname: Lee
authors.forename: Ik-Kyung
authors.initials: IK
authors.lastname: Jang
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis; D000368:Aged; D060050:Angina, Stable / Q000175:diagnosis; D015331:Cohort Studies; D003331:Coronary Vessels / Q000737:chemistry* / Q000473:pathology; D005260:Female; D006801:Humans; D008055:Lipids / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000737:chemistry* / Q000473:pathology; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D008055:Lipids
keywords: atherosclerosis; optical coherence tomography; plaque; spectroscopy