title: Shape-based approach for coronary calcium lesion volume measurement on intravascular ultrasound imaging and its association with carotid intima-media thickness.
abstract: OBJECTIVE
  Coronary calcification plays an important role in diagnostic classification of lesion subsets. According to histopathologic studies, vulnerable atherosclerotic plaque contains calcified deposits, and there can be considerable variation in the extent and degree of calcification. Intravascular ultrasound (IVUS) has demonstrated its role in imaging coronary arteries, thereby displaying calcium lesions. The aim of this work was to develop a fully automated system for detection, area and volume measurement, and characterization of the largest calcium deposits in coronary arteries. Furthermore, we demonstrate the correlation between the coronary calcium IVUS volume and the neurologic risk biomarker B-mode carotid intima-media thickness (IMT).
  
  
  METHODS
  Our system automatically detects the frames with calcium, identifies the largest calcium region, and performs shape-based volume measurements. The carotid IMT is measured by using AtheroEdge software (AtheroPoint, LLC) on B-mode ultrasound imaging.
  
  
  RESULTS
  Our database consists of low-contrast IVUS videos and corresponding B-mode images from 100 patients. Our experiments showed that the correlation between calcium volumes and carotid IMT was higher for the left carotid artery compared to the right carotid artery (r = 0.066 for the left carotid artery and 0.121 for the right carotid artery). We obtained 97% accuracy for automated calcium detection compared against the scoring given by our expert radiologists. Furthermore, we benchmarked shape-based volume measurement against the conventional method, which used integration of regions and showed a correlation of 84%.
  
  
  CONCLUSIONS
  Since carotid IMT is an independent prognostic factor for myocardial infarction, and calcium lesions are correlated with stroke risk, we believe that this automated system for calcium volume measurement could be useful for assessing patients' cardiovascular risk.
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.).
authors.forename: Tadashi
authors.initials: T
authors.lastname: Araki
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.).
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Ikeda
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.).
authors.forename: Nilanjan
authors.initials: N
authors.lastname: Dey
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.).
authors.forename: Suvojit
authors.initials: S
authors.lastname: Acharjee
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.).
authors.forename: Filippo
authors.initials: F
authors.lastname: Molinari
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.).
authors.forename: Luca
authors.initials: L
authors.lastname: Saba
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.).
authors.forename: Elisa Cuadrado
authors.initials: EC
authors.lastname: Godia
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.).
authors.forename: Andrew
authors.initials: A
authors.lastname: Nicolaides
authors.affiliation: Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Tokyo, Japan (T.A.); Division of Cardiovascular Medicine, National Center for Global Health and Medicine, Tokyo, Japan (N.I.); Point of Care Devices, Global Biomedical Technologies, Inc, Roseville, California USA (N.D., S.A., J.S.S.); Biolab, Department of Electronics, Politecnico di Torino, Torino, Italy (F.M.); Azienda Ospedaliero Universitaria di Cagliari-Polo di Monserrato, Università di Cagliari, Cagliari, Italy (L.S.); Institut Hospital del Mar d'Investigacions Mèdiques, Hospital del Mar, Barcelona, Spain (E.C.G.); Vascular Screening and Diagnostic Center, London, England (A.N.); Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus (A.N.); Diagnostic and Monitoring Division, AtheroPoint, LLC, Roseville, California USA (J.S.S.); and Department of Electrical Engineering (Affiliate), Idaho State University, Pocatello, Idaho USA (J.S.S.). jasjit.suri@atheropoint.com.
authors.forename: Jasjit S
authors.initials: JS
authors.lastname: Suri
mesh_terms: D001185:Artificial Intelligence; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D059168:Carotid Intima-Media Thickness; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional / Q000379:methods*
keywords: carotid intima-media thickness; coronary calcium; shape-based volume measurement; vascular ultrasound