title: Analysis of myocardial perfusion parameters in an ex-vivo porcine heart model using third generation dual-source CT.
abstract: OBJECTIVE
  To evaluate the relationship between fractional flow reserve (FFR)-determined coronary artery stenosis severity and myocardial perfusion parameters derived from dynamic myocardial CT perfusion imaging (CTP) in an ex-vivo porcine heart model.
  
  
  METHODS
  Six porcine hearts were perfused according to Langendorff. Circulatory parameters such as arterial blood flow (ABF) (L/min), mean arterial pressure (MAP) (mmHg) and heart rate (bpm) were monitored. Using an inflatable cuff and monitored via a pressure wire, coronary artery stenoses of different FFR grades were created (no stenosis, FFR = 0.80, FFR = 0.70, FFR = 0.60, and FFR = 0.50). Third generation dual-source CT was used to perform dynamic CTP in shuttle mode at 70 kV. Using the AHA-16-segment model, myocardial blood flow (MBF) (mL/100 mL/min) and volume (MBV) (mL/100 mL) were analyzed using dedicated software for all ischaemic and non-ischaemic segments.
  
  
  RESULTS
  During five successful experiments, ABF ranged from 0.8 to 1.2 L/min, MAP from 73 to 90 mmHg and heart rate from 83 to 115 bpm. Non-ischaemic and ischaemic segments showed significant differences in MBF for stenosis grades of FFR ≤ 0.70. At this degree of obstruction, median MBF was 79 (interquartile range [IQR]: 66-90) for non-ischaemic segments versus 56 mL/100 mL/min (IQR: 46-73) for ischaemic segments (p < 0.05). For MBV, a significant difference was found at FFR ≤ 0.80 with median MBV values of 7.6 (IQR: 7.0-8.3) and 7.1 mL/100 mL (IQR: 6.0-8.2) for non-ischaemic and ischaemic myocardial segments, respectively (p < 0.05).
  
  
  CONCLUSIONS
  Artificial flow alterations in a Langendorff porcine heart model could be detected and measured by CTP-derived myocardial perfusion parameters and showed significant systematic correlation with stepwise flow reduction that permitted early detection of ischaemic myocardium. Additional research in clinical setting is required to develop absolute quantitative CTP.
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
authors.forename: Gert Jan
authors.initials: GJ
authors.lastname: Pelgrim
authors.affiliation: Medical University of South Carolina, Department of Radiology, 25 Courtenay Drive, 29425 SC, Charleston, SC, USA.
authors.forename: Taylor M
authors.initials: TM
authors.lastname: Duguay
authors.affiliation: LifeTec Group BV, Kennedyplein 10-11, 5611 ZS, Eindhoven, The Netherlands.
authors.forename: J Marco A
authors.initials: JM
authors.lastname: Stijnen
authors.affiliation: Medical University of South Carolina, Department of Radiology, 25 Courtenay Drive, 29425 SC, Charleston, SC, USA.
authors.forename: Akos
authors.initials: A
authors.lastname: Varga-Szemes
authors.affiliation: LifeTec Group BV, Kennedyplein 10-11, 5611 ZS, Eindhoven, The Netherlands.
authors.forename: Sjoerd
authors.initials: S
authors.lastname: Van Tuijl
authors.affiliation: Medical University of South Carolina, Department of Radiology, 25 Courtenay Drive, 29425 SC, Charleston, SC, USA.
authors.forename: U Joseph
authors.initials: UJ
authors.lastname: Schoepf
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
authors.forename: Matthijs
authors.initials: M
authors.lastname: Oudkerk
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Medical Imaging - North East Netherlands, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Department of Radiology, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands. Electronic address: r.vliegenthart@umcg.nl.
authors.forename: Rozemarijn
authors.initials: R
authors.lastname: Vliegenthart
mesh_terms: D000818:Animals; D062186:Arterial Pressure; D001783:Blood Flow Velocity; D000072226:Computed Tomography Angiography; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004195:Disease Models, Animal; D053805:Fractional Flow Reserve, Myocardial; D006339:Heart Rate; D000067268:Isolated Heart Preparation; D008955:Models, Cardiovascular; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012720:Severity of Illness Index; D034421:Sus scrofa
keywords: Animal model; Iodine; Ischemia; Myocardial perfusion imaging; Tomography; X-ray computed