title: The impact of warmed intravenous contrast material on the bolus geometry of coronary CT angiography applications.
abstract: OBJECTIVE
  This study was designed to investigate the effect of administration of warmed contrast material (CM) on the bolus geometry and enhancement as depicted on coronary CT angiography.
  
  
  METHODS
  A total of 64 patients (42 men, 22 women; mean age, 56 years) were randomly divided into two groups. Group 1 included 32 patients administered CM (Omnipaque [Iohexol] 350 mg I/ mL; Nycomed, Princeton, NJ) saline solutions kept in an incubator at a constant temperature (37 degrees C). Group 2 included 32 patients administered the CM saline solutions kept at constant room temperature (24 degrees C). Cardiac CT scans were performed with a dual source computed tomography (DSCT) scanner. For each group, region of interest curves were plotted inside the ascending aorta, main pulmonary artery and descending aorta on test bolus images. Using enhancement values, time/enhancement diagrams were produced for each vessel. On diagrams, basal Hounsfield unit (HU) values were subtracted from sequentially obtained values. A value of 100 HU was accepted as a cut-off value for the beginning of opacification. The time to peak, the time required to reach 100 HU opacification, maximum enhancement and duration of enhancement above 100 HU were noted. DSCT angiography studies were evaluated for coronary vessel enhancement.
  
  
  RESULTS
  Maximum enhancement values in the ascending aorta, descending aorta and main pulmonary artery were significantly higher in group 1 subjects. In the ascending aorta, the median time required to reach 100 HU opacification during the test bolus analysis was significantly shorter for group 2 subjects than for group 1 subjects. In the ascending aorta, the descending aorta and main pulmonary artery, for group 1 subjects, the bolus geometry curve shifted to the left and upwards as compared with the bolus geometry curve for group 2 subjects.
  
  
  CONCLUSIONS
  The use of warmed CM yields higher enhancement values and a shorter time to reach maximum enhancement duration, resulting in a shift of the bolus geometry curve to the left that may provide optimized image quality.
authors.affiliation: Department of Radiology, Hacettepe University School of Medicine, Ankara, Turkey.
authors.forename: Tuncay
authors.initials: T
authors.lastname: Hazirolan
authors.forename: Baris
authors.initials: B
authors.lastname: Turkbey
authors.forename: Erhan
authors.initials: E
authors.lastname: Akpinar
authors.forename: Murat
authors.initials: M
authors.lastname: Canyigit
authors.forename: Musturay
authors.initials: M
authors.lastname: Karcaaltincaba
authors.forename: Bora
authors.initials: B
authors.lastname: Peynircioglu
authors.forename: Z Dicle
authors.initials: ZD
authors.lastname: Balkanci
authors.forename: Deniz
authors.initials: D
authors.lastname: Akata
authors.forename: Ferhun
authors.initials: F
authors.lastname: Balkanci
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D007275:Injections, Intravenous; D007472:Iohexol / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013696:Temperature; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol