title: Quantitative evaluation of the performance of a new test bolus-based computed tomographic angiography contrast-enhancement-prediction algorithm.
abstract: OBJECTIVE
  The objective of this study was to assess the robustness of a novel test bolus (TB)-based computed tomographic angiography (CTA) contrast-enhancement-prediction (CEP) algorithm by retrospectively quantifying the systematic and random errors between the predicted and true enhancements.
  
  
  METHODS
  All local institutional review boards approved this retrospective study, in which a total of 72 (3 × 24) anonymized cardiac CTA examinations were collected from 3 hospitals. All patients (46 men; median age, 62 years [range, 31-81 years]) underwent a TB scan and a cardiac CTA according to local scan and injection protocols. For each patient, a shorter TB signal and TB signals with lower temporal resolution were derived from the original TB signal. The CEP algorithm predicted the enhancement in the descending aorta (DAo) on the basis of the TB signals in the DAo, the injection protocols and kilovolt settings, as well as population-averaged blood circulation characteristics. The true enhancement was extracted with a region of interest along the DAo centerline. For each patient, the errors in timing and amplitude were calculated; differences between the hospitals were assessed using the 1-way analysis of variance (P < 0.05) and variations between the TB signals were assessed using the within-subject standard deviation.
  
  
  RESULTS
  No significant differences were found between the 3 hospitals for any of the TB signals. With errors in the amplitude and timing of 0.3% ± 15.6% and -0.2 ± 2.0 seconds, respectively, no clinically relevant systematic errors existed. Shorter- and coarser-time-sampled TB signals introduced a within-subject standard deviation of 4.0% and 0.5 seconds, respectively.
  
  
  CONCLUSIONS
  This TB-based CEP algorithm has no systematic errors in the timing and amplitude of predicted enhancements and is robust against coarser-time-sampled and incomplete TB scans.
authors.affiliation: From the *Siemens AG Healthcare Sector, Imaging & Therapy Division, Computed Tomography, Forchheim; †Department of Diagnostic and Interventional Radiology, University Hospital, Philipps University of Marburg, Marburg, Germany; ‡Department of Imaging Methods, Charles University and University Hospital Pilsen, Pilsen, Czech Republic; §Institut für Radiologie und Nuklearmedizin, Deutsches Herzzentrum München, Klinik an der Technischen Universität München; ∥1. Medizinische Klinik, Ludwig-Maximilians-Universität München, Munich; ¶Department of Diagnostic Radiology, Eberhard-Karls-Universität Tübingen, Tübingen; and #Institute of Medical Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Germany.
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Korporaal
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
authors.forename: Jiří
authors.initials: J
authors.lastname: Ferda
authors.forename: Jörg
authors.initials: J
authors.lastname: Hausleiter
authors.forename: Jan
authors.initials: J
authors.lastname: Baxa
authors.forename: Martin
authors.initials: M
authors.lastname: Hadamitzky
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Flohr
authors.forename: Bernhard T
authors.initials: BT
authors.lastname: Schmidt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol