title: Histopathological validation of optical frequency domain imaging to quantify various types of coronary calcifications.
abstract: OBJECTIVE
  This study evaluated whether optical frequency domain imaging (OFDI) could identify various coronary calcifications and accurately measure calcification thickness in comparison with histopathology.
  
  
  RESULTS
  A total of 902 pathological cross-sections from 44 coronary artery specimens of human cadavers were examined to compare OFDI and histological images. Histological coronary calcification was classified into four different types: (i) superficial dense calcified plates, (ii) deep intimal calcification, (iii) scattered microcalcification, and (iv) calcified nodule. The thickness of calcification was measured when both the leading and trailing edges of calcification were visible on OFDI. Of the 902 histological cross-sections, 158 (18%) had calcification: 105 (66%) were classified as superficial dense calcified plates, 20 (13%) as deep intimal calcifications, 30 (19%) as scattered microcalcifications, and 3 (2%) as calcified nodules. Superficial dense calcified plates appeared as well-delineated heterogeneous signal-poor regions with sharp borders on OFDI. Deep intimal calcifications could not be identified on OFDI. Scattered microcalcification appeared as homogeneous low intensity areas with indiscriminant borders. Calcified nodule, a high-backscattering protruding mass with an irregular surface, also appeared as a low intensity area with a diffuse border. The ROC analysis identified calcium thicknesses <893 µm as cut points for the prediction of measurable calcification (72% sensitivity and 91% specificity, area under the curve = 0.893, P < 0.001).
  
  
  CONCLUSIONS
  Our study demonstrated the potential capability of OFDI to characterize various types of coronary calcifications, which may contribute to the understanding of the pathogenesis of coronary atherosclerosis.
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Ten
authors.initials: T
authors.lastname: Saita
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Fujii
authors.affiliation: Department of Surgical Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hao
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Imanaka
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Shibuya
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Fukunaga
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Kojiro
authors.initials: K
authors.lastname: Miki
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Tamaru
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Horimatsu
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Machiko
authors.initials: M
authors.lastname: Nishimura
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Sumiyoshi
authors.affiliation: Department of Surgical Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Kawakami
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Naito
authors.affiliation: Department of Surgical Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Kajimoto
authors.affiliation: Department of Surgical Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Hirota
authors.affiliation: Cardiovascular Division, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 6638501, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Masuyama
mesh_terms: D000368:Aged; D001707:Biopsy, Needle; D002102:Cadaver; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000473:pathology*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007150:Immunohistochemistry; D008297:Male; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*; D061205:Vascular Calcification / Q000000981:diagnostic imaging* / Q000473:pathology*
keywords: atherosclerosis; calcification; optical frequency domain imaging