title: Real-time respiratory triggered SPECT myocardial perfusion imaging using CZT technology: impact of respiratory phase matching between SPECT and low-dose CT for attenuation correction.
abstract: OBJECTIVE
  To assess the impact of respiratory phase matching between single-photon-emission computed tomography myocardial perfusion imaging (SPECT-MPI) and low-dose computed tomography (CT) for attenuation correction (AC).
  
  
  RESULTS
  Forty patients underwent 1-day99mTc-tetrofosmin pharmacological stress/rest SPECT-MPI using a cadmium-zinc-telluride gamma camera. Low-dose CT for AC was performed at deep-inspiration breath-hold. SPECT-MPI was acquired once with free-breathing (FB) and repeated at deep-inspiration breath-hold (BH) to match the respiratory phase of AC. From these acquisitions we reconstructed four data sets: free-breathing SPECT-MPI without AC (non-corrected; FB-NC), breath-hold SPECT-MPI without AC (non-corrected; BH-NC), free-breathing SPECT-MPI with AC (FB-AC), and breath-hold SPECT-MPI with AC (BH-AC), the latter representing respiratory-phase-matched AC SPECT-MPI. We compared semi-quantitative segmental tracer uptake, visual diagnosis, inter-observer agreement, and image quality. Compared with FB-NC, deep-inspiration BH-NC increases inferior and lateral uptake, but decreases septal uptake. Addition of AC to FB increases inferior and septal uptake, but decreases anterolateral uptake. Combining breath-hold MPI with breath-hold CT AC (BH-AC) increases inferior, inferolateral, and septal uptake, but reduces apical uptake, without affecting anterolateral uptake, with significant differences to all other protocols. Frequency of normal scans increases across protocols: 10% with FB-NC, 21% with BH-NC, 38% with FB-AC, and 51% with BH-AC. Image quality and inter-observer agreement were highest for BH-AC among all protocols.
  
  
  CONCLUSIONS
  Compared with non-corrected breath-hold SPECT-MPI and with free-breathing AC SPECT-MPI, respiratory-phase-matched AC SPECT-MPI significantly affects segmental semi-quantitative uptake, increases the frequency of normal scans, yields the best inter-observer agreement, and significantly improves image quality. These findings suggest a potential role of respiratory triggered SPECT-MPI in clinical routine.
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Olivier F
authors.initials: OF
authors.lastname: Clerc
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Tobias A
authors.initials: TA
authors.lastname: Fuchs
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Mathias
authors.initials: M
authors.lastname: Possner
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Vontobel
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Fran
authors.initials: F
authors.lastname: Mikulicic
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Julia
authors.initials: J
authors.lastname: Stehli
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Liga
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Dominik C
authors.initials: DC
authors.lastname: Benz
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Gräni
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Aju P
authors.initials: AP
authors.lastname: Pazhenkottil
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Gaemperli
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland ronny.buechel@usz.ch.
authors.forename: Ronny R
authors.initials: RR
authors.lastname: Buechel
authors.affiliation: Cardiac Imaging, Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
mesh_terms: D000368:Aged; D002104:Cadmium; D015331:Cohort Studies; D000072226:Computed Tomography Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011446:Prospective Studies; D011877:Radionuclide Imaging / Q000379:methods*; D012119:Respiration; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013691:Tellurium; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D015032:Zinc
chemical_list: C474490:CdZnTe; D002104:Cadmium; D015032:Zinc; D013691:Tellurium
keywords: CT attenuation correction; CZT; SPECT; cardiac imaging; respiratory phase