title: Low contrast volume run-off CT angiography with optimized scan time based on double-level test bolus technique--feasibility study.
abstract: OBJECTIVE
  To verify the technical feasibility of low contrast volume (40 mL) run-off CT angiography (run-off CTA) with the individual scan time optimization based on double-level test bolus technique.
  
  
  METHODS
  A prospective study of 92 consecutive patients who underwent run-off CTA performed with 40 mL of contrast medium (injection rate of 6 mL/s) and optimized scan times on a second generation of dual-source CT. Individual optimized scan times were calculated from aortopopliteal transit times obtained on the basis of double-level test bolus technique--the single injection of 10 mL test bolus and dynamic acquisitions in two levels (abdominal aorta and popliteal arteries). Intraluminal attenuation (HU) was measured in 6 levels (aorta, iliac, femoral and popliteal arteries, middle and distal lower-legs) and subjective quality (3-point score) was assessed. Relations of image quality, test bolus parameters and arterial circulation involvement were analyzed.
  
  
  RESULTS
  High mean attenuation (HU) values (468; 437; 442; 440; 342; 274) and quality score in all monitored levels was achieved. In 91 patients (0.99) the sufficient diagnostic quality (score 1-2) in aorta, iliac and femoral arteries was determined. A total of 6 patients (0.07) were not evaluable in distal lower-legs. Only the weak indirect correlation of image quality and test-bolus parameters was proved in iliac, femoral and popliteal levels (r values: -0.263, -0.298 and -0.254). The statistically significant difference of the test-bolus parameters and image quality was proved in patients with occlusive and aneurysmal disease.
  
  
  CONCLUSIONS
  We proved the technical feasibility and sufficient quality of run-off CTA with low volume of contrast medium and optimized scan time according to aortopopliteal transit time calculated from double-level test bolus.
authors.affiliation: Department of Imaging Methods, University Hospital and Charles University Medical School in Pilsen, Czech Republic. Electronic address: baxaj@fnplzen.cz.
authors.forename: Jan
authors.initials: J
authors.lastname: Baxa
authors.affiliation: Department of Imaging Methods, University Hospital and Charles University Medical School in Pilsen, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Vendiš
authors.affiliation: Department of Surgery, University Hospital and Charles University Medical School in Pilsen, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Moláček
authors.affiliation: Department of Internal Medicine, University Hospital and Charles University Medical School in Pilsen, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Stěpánková
authors.affiliation: Siemens Healthcare, Computed Tomography Division, Forchheim, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Flohr
authors.affiliation: Siemens Healthcare, Computed Tomography Division, Forchheim, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.affiliation: Siemens Healthcare, Computed Tomography Division, Forchheim, Germany.
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Korporaal
authors.affiliation: Department of Imaging Methods, University Hospital and Charles University Medical School in Pilsen, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Ferda
mesh_terms: D000465:Algorithms; D000792:Angiography / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005240:Feasibility Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007269:Injections, Intra-Arterial; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: CT angiography; Contrast medium; Peripheral vascular disease; Run-off; Test bolus