title: CT-based attenuation correction in I-123-ioflupane SPECT.
abstract: OBJECTIVE
  Attenuation correction (AC) based on low-dose computed tomography (CT) could be more accurate in brain single-photon emission computed tomography (SPECT) than the widely used Chang method, and, therefore, has the potential to improve both semi-quantitative analysis and visual image interpretation. The present study evaluated CT-based AC for dopamine transporter SPECT with I-123-ioflupane.
  
  
  METHODS
  Sixty-two consecutive patients in whom I-123-ioflupane SPECT including low-dose CT had been performed were recruited retrospectively at 3 centres. For each patient, 3 different SPECT images were reconstructed: without AC, with Chang AC and with CT-based AC. Distribution volume ratio (DVR) images were obtained by scaling voxel intensities using the whole brain without striata as reference. For assessing the impact of AC on semi-quantitative analysis, specific-to-background ratios (SBR) in caudate and putamen were obtained by fully automated SPM8-based region of interest (ROI) analysis and tested for their diagnostic power using receiver-operator-characteristic (ROC) analysis. For assessing the impact of AC on visual image reading, screenshots of stereotactically normalized DVR images presented in randomized order were interpreted independently by two raters at each centre.
  
  
  RESULTS
  CT-based AC resulted in intermediate SBRs about half way between no AC and Chang. Maximum area under the ROC curve was achieved by the putamen SBR, with negligible impact of AC (0.924, 0.935 and 0.938 for no, CT-based and Chang AC). Diagnostic accuracy of visual interpretation also did not depend on AC.
  
  
  CONCLUSIONS
  The impact of CT-based versus Chang AC on the interpretation of I-123-ioflupane SPECT is negligible. Therefore, CT-based AC cannot be recommended for routine use in clinical patient care, not least because of the additional radiation exposure.
authors.affiliation: Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Catharina
authors.initials: C
authors.lastname: Lange
authors.affiliation: Department of Nuclear Medicine, Universitätsklinikum Leipzig, Leipzig, Germany.
authors.forename: Anita
authors.initials: A
authors.lastname: Seese
authors.affiliation: Department of Nuclear Medicine, Universitätsmedizin Rostock, Rostock, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Schwarzenböck
authors.affiliation: Department of Nuclear Medicine, Universitätsklinikum Leipzig, Leipzig, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Steinhoff
authors.affiliation: GE Healthcare Buchler GmbH & Co. KG, Munich, Germany.
authors.forename: Bert
authors.initials: B
authors.lastname: Umland-Seidler
authors.affiliation: Department of Nuclear Medicine, Universitätsmedizin Rostock, Rostock, Germany.
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Krause
authors.affiliation: Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Winfried
authors.initials: W
authors.lastname: Brenner
authors.affiliation: Department of Nuclear Medicine, Universitätsklinikum Leipzig, Leipzig, Germany.
authors.forename: Osama
authors.initials: O
authors.lastname: Sabri
authors.affiliation: Department of Nuclear Medicine, Universitätsmedizin Rostock, Rostock, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kurth
authors.affiliation: Department of Nuclear Medicine, Universitätsklinikum Leipzig, Leipzig, Germany.
authors.forename: Swen
authors.initials: S
authors.lastname: Hesse
authors.affiliation: Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Buchert
mesh_terms: D000368:Aged; D016477:Artifacts; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D007457:Iodine Radioisotopes; D008875:Middle Aged; D009662:Nortropanes; D020734:Parkinsonian Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D012372:ROC Curve; D012189:Retrospective Studies; D059629:Signal-To-Noise Ratio; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation / Q000592:standards*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000592:standards*
chemical_list: D007457:Iodine Radioisotopes; D009662:Nortropanes; C519528:ioflupane