title: IQ-SPECT for thallium-201 myocardial perfusion imaging: effect of normal databases on quantification.
abstract: OBJECTIVE
  Although IQ-single-photon emission computed tomography (SPECT) provides rapid acquisition and attenuation-corrected images, the unique technology may create characteristic distribution different from the conventional imaging. This study aimed to compare the diagnostic performance of IQ-SPECT using Japanese normal databases (NDBs) with that of the conventional SPECT for thallium-201 (201Tl) myocardial perfusion imaging (MPI).
  
  
  METHODS
  A total of 36 patients underwent 1-day201Tl adenosine stress-rest MPI. Images were acquired with IQ-SPECT at approximately one-quarter of the standard time of conventional SPECT. Projection data acquired with the IQ-SPECT system were reconstructed via an ordered subset conjugate gradient minimizer method with or without scatter and attenuation correction (SCAC). Projection data obtained using the conventional SPECT were reconstructed via a filtered back projection method without SCAC. The summed stress score (SSS) was calculated using NDBs created by the Japanese Society of Nuclear Medicine working group, and scores were compared between IQ-SPECT and conventional SPECT using the acquisition condition-matched NDBs. The diagnostic performance of the methods for the detection of coronary artery disease was also compared.
  
  
  RESULTS
  SSSs were 6.6 ± 8.2 for the conventional SPECT, 6.6 ± 9.4 for IQ-SPECT without SCAC, and 6.5 ± 9.7 for IQ-SPECT with SCAC (p = n.s. for each comparison). The SSS showed a strong positive correlation between conventional SPECT and IQ-SPECT (r = 0.921 and p < 0.0001), and the correlation between IQ-SPECT with and without SCAC was also good (r = 0.907 and p < 0.0001). Regarding diagnostic performance, the sensitivity, specificity, and accuracy were 80.8, 78.9, and 79.4%, respectively, for the conventional SPECT; 80.8, 80.3, and 82.0%, respectively, for IQ-SPECT without SCAC; and 88.5, 86.8, and 87.3%, respectively, for IQ-SPECT with SCAC, respectively. The area under the curve obtained via receiver operating characteristic analysis were 0.77, 0.80, and 0.86 for conventional SPECT, IQ-SPECT without SCAC, and IQ-SPECT with SCAC, respectively (p = n.s. for each comparison).
  
  
  CONCLUSIONS
  When appropriate NDBs were used, the diagnostic performance of201Tl IQ-SPECT was comparable with that of the conventional system regardless of different characteristics of myocardial accumulation in the conventional system.
authors.affiliation: Department of Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Takahiro
authors.identifier: http://orcid.org/0000-0003-0461-5582
authors.initials: T
authors.lastname: Konishi
authors.affiliation: Department of Nuclear Medicine, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641, Japan. nakajima@med.kanazawa-u.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: Department of Physics, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku, Ishikawa, 920-0293, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Okuda
authors.affiliation: Department of Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Yoneyama
authors.affiliation: Department of Nuclear Medicine, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Shinro
authors.initials: S
authors.lastname: Matsuo
authors.affiliation: Department of Quantum Medical Technology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 920-0942, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Shibutani
authors.affiliation: Department of Quantum Medical Technology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 920-0942, Japan.
authors.forename: Masahisa
authors.initials: M
authors.lastname: Onoguchi
authors.affiliation: Department of Nuclear Medicine, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Seigo
authors.initials: S
authors.lastname: Kinuya
mesh_terms: D000368:Aged; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D055414:Myocardial Perfusion Imaging; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D013794:Thallium Radioisotopes
keywords: IQ-SPECT; Japanese normal databases; Myocardial perfusion imaging; Rapid acquisition