title: Single-bolus technique for spiral CT of laryngopharyngeal squamous cell carcinoma: comparison of different contrast material volumes, flow rates, and start delays.
abstract: OBJECTIVE
  To evaluate different contrast material volumes, flow rates, and start delays for contrast material enhancement of neck structures and squamous cell carcinoma to determine the most effective examination protocol.
  
  
  METHODS
  Seventy patients with squamous cell carcinoma were prospectively randomized into four groups for examination with different protocols (125 mL of contrast material administered at a flow rate of 2.5 mL/sec, 100 mL at 2.0 mL/sec, 90 mL at 1.5 mL/sec, or 70 mL at 1.0 mL/sec). Dynamic series were performed on the tumors and relevant anatomic structures to obtain time-attenuation curves. The protocols were compared (analysis of variance and Tukey-Kramer tests) with regard to time and level of maximum tumor enhancement and carotid arterial enhancement of more than 150 HU. One selected protocol was tested in 30 additional routine examinations with start delays of 40 seconds (for laryngeal and/or hypopharyngeal tumors, 3-mm collimation) and 45 seconds (for oropharyngeal tumors, 5-mm collimation).
  
  
  RESULTS
  Except for the 70-mL bolus administered at 1.0 mL/sec, the other protocols performed similarly well, yielding comparable maximum tumor enhancement at 52 seconds and later. In spite of a smaller volume of 90 mL, due to the prolonged flow time at 1.5 mL/sec, carotid arterial enhancement of more than 150 HU was prolonged (when compared with that in 100- or 125-mL protocols). As a result of these circumstances, injection of 90 mL at 1.5 mL/sec was considered more effective, providing no significant differences in tumor (P =.39) or carotid arterial (P =.52) enhancement between routine examinations and dynamic series.
  
  
  CONCLUSIONS
  A single bolus of 90 mL administered at 1.5 mL/sec appears to be the most desirable protocol for contrast enhancement.
authors.affiliation: Department of Radiology, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany. marc.keberle@mail.uni-wuerzburg.de
authors.forename: Marc
authors.initials: M
authors.lastname: Keberle
authors.forename: Alexander
authors.initials: A
authors.lastname: Tschammler
authors.forename: Dietbert
authors.initials: D
authors.lastname: Hahn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007013:Hypopharynx; D007822:Laryngeal Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009959:Oropharyngeal Neoplasms / Q000000981:diagnostic imaging; D010610:Pharyngeal Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media