title: Computed Tomography Angiography With High Flow Rates: An In Vitro and In Vivo Feasibility Study.
abstract: OBJECTIVE
  The aims of this study were to test high-flow application of contrast media (CM) using novel high-flow needles and to assess injection- and flow-related parameters in a circulation phantom and in an in vivo population.
  
  
  METHODS
  A circulation phantom simulating physiological parameters was used. Preheated CM (300 mg/mL) was injected at flow rates varying between 5 and 15 mL/s through a novel 18-gauge high-flow intravenous injection needle. In addition, feasibility of these high-flow needles was tested with administration of flow rates of 9 mL/s in 20 patients referred for pre-transcatheter aortic valve implantation assessment. Injection parameters (eg, peak pressures, peak flow rates) in both phantom and in vivo setup were continuously monitored by a data acquisition program. Attenuation at predefined levels of the aorta (eg, aortic root to common femoral arteries) was measured in all patients to determine clinical applicability.
  
  
  RESULTS
  In the phantom setup, injection rates up to 15 mL/s were feasible. An enhancement plateau was reached at 11 mL/s (464 [20] HU). In patients, no pressure- or flow-related complications (eg, extravasation) were recorded (mean [SD] peak pressure, 154 [8] psi; mean [SD] peak flow rate, 9.2 [0.1 mL/s; range, 9.1-9.6]). Diagnostic attenuation values were reached at all predefined levels of the aorta (330.8 [113.1] HU to 622.9 [81.5] HU).
  
  
  CONCLUSIONS
  These results indicate that injections with 9 mL/s using high-flow injection needles are safe. The pressure limit of 325 psi was not reached, and the injections resulted in diagnostic attenuation values. Using this dedicated needle, high flow rates should not be considered a drawback for CM application in routine CT angiography examinations.
authors: From the *Department of Radiology and †CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, the Netherlands; and ‡Department of Neuroradiology, University Hospital RWTH Aachen, Aachen, Germany.
authors: Casper
authors: C
authors: Mihl
authors: Madeleine
authors: M
authors: Kok
authors: Joachim E
authors: JE
authors: Wildberger
authors: Jakub
authors: J
authors: Turek
authors: Georg
authors: G
authors: Muehlenbruch
authors: Marco
authors: M
authors: Das
mesh_terms: D000465:Algorithms; D000792:Angiography / Q000379:methods*; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging*; D001027:Aortography / Q000379:methods*; D001783:Blood Flow Velocity; D005240:Feasibility Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*