title: Myocardial CT perfusion imaging in a large animal model: comparison of dynamic versus single-phase acquisitions.
abstract: OBJECTIVE
  This study sought to compare dynamic versus single-phase high-pitch computed tomography (CT) acquisitions for the assessment of myocardial perfusion in a porcine model with adjustable degrees of coronary stenosis.
  
  
  BACKGROUND
  The incremental value of the 2 different approaches to CT-based myocardial perfusion imaging remains unclear.
  
  
  METHODS
  Country pigs received stent implantation in the left anterior descending coronary artery, in which an adjustable narrowing (50% and 75% stenoses) was created using a balloon catheter. All animals underwent CT-based rest and adenosine-stress myocardial perfusion imaging using dynamic and single-phase high-pitch acquisitions at both degrees of stenosis. Fluorescent microspheres served as a reference standard for myocardial blood flow. Segmental CT-based myocardial blood flow (MBFCT) was derived from dynamic acquisitions. Segmental single-phase enhancement (SPE) was recorded from high-pitch, single-phase examinations. MBFCT and SPE were compared between post-stenotic and reference segments, and receiver-operating characteristic curve analysis was performed.
  
  
  RESULTS
  Among 6 animals (28 ± 2 kg), there were significant differences of MBFCT and SPE between post-stenotic and reference segments for all acquisitions at 75% stenosis. By contrast, although for 50% stenosis at rest, MBFCT was lower in post-stenotic than in reference segments (0.65 ± 0.10 ml/g/min vs. 0.75 ± 0.16 ml/g/min, p < 0.05), there was no difference for SPE (128 ± 27 Hounsfield units vs. 137 ± 35 Hounsfield units, p = 0.17), which also did not significantly change under adenosine stress. In receiver-operating characteristic curve analyses, segmental MBFCT showed significantly better performance for ischemia prediction at 75% stenosis and stress (area under the curve: 0.99 vs. 0.89, p < 0.05) as well as for 50% stenosis, regardless of adenosine administration (area under the curve: 0.74 vs. 0.57 and 0.88 vs. 0.61, respectively, both p < 0.05).
  
  
  CONCLUSIONS
  At higher degrees of coronary stenosis, both MBFCT and SPE permit an accurate prediction of segmental myocardial hypoperfusion. However, accuracy of MBFCT is higher than that of SPE at 50% stenosis and can be increased by adenosine stress at both degrees of stenosis.
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Schwarz
authors.affiliation: Department of Cardiology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Rabea
authors.initials: R
authors.lastname: Hinkel
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Baloch
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Roy P
authors.initials: RP
authors.lastname: Marcus
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Kristof
authors.initials: K
authors.lastname: Hildebrandt
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Torleif A
authors.initials: TA
authors.lastname: Sandner
authors.affiliation: Department of Cardiology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kupatt
authors.affiliation: Department of Biostatistics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Hoffmann
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany; Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Wintersperger
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany; DZHK (German Center for Cardiovascular Research) and Munich Heart Alliance, Munich, Germany.
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany; DZHK (German Center for Cardiovascular Research) and Munich Heart Alliance, Munich, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Theisen
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany; DZHK (German Center for Cardiovascular Research) and Munich Heart Alliance, Munich, Germany.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians-University, Munich, Germany; DZHK (German Center for Cardiovascular Research) and Munich Heart Alliance, Munich, Germany. Electronic address: fbamberg@med.lmu.de.
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
mesh_terms: D000241:Adenosine; D000818:Animals; D019540:Area Under Curve; D003287:Contrast Media; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013552:Swine; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014665:Vasodilator Agents
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents; D007472:Iohexol; C038192:iopromide; D000241:Adenosine
keywords: AUC; CT; CTA; FM; HU; Hounsfield units; MBF(CT); MBF(MIC); ROC; ROI; SPE; area under the curve; cardiac CT; computed tomography; computed tomography angiography; computed tomography–derived myocardial blood flow; fluorescent microsphere(s); infarct; ischemia; microsphere-derived myocardial blood flow; myocardial perfusion; receiver-operating characteristic; region of interest; single-phase enhancement