title: A reduced contrast volume acquisition regimen based on cardiovascular dynamics improves visualisation of head and neck vasculature with carotid MDCT angiography.
abstract: OBJECTIVE
  To investigate enhancement of head and neck arteries during carotid computed tomography angiography using a reduced volume contrast regimen and craniocaudal scan acquisition.
  
  
  METHODS
  Two hundred and two patients underwent carotid angiography using a 64 channel computed tomography scanner. Patients were allocated to one of two acquisition/contrast regimens: regimen A, the department's standard protocol, consisting of a caudocranial scan direction with 100mL of contrast intravenously; regimen B, involving a craniocaudal scan direction and approximately 50 mL of contrast using a timing dictated by patient hemodynamics. Attenuation profiles of cranial arteries and veins in 6 anatomical segments were assessed and arteriovenous contrast ratios (AVCR) calculated. Receiver operating characteristic (ROC) analysis was performed using DBM methodology.
  
  
  RESULTS
  Arterial attenuation was up to 54% (p<0.01) higher following regimen B compared with A. Attenuation in the veins were significantly lower in regimen B than in regimen A with a maximum reduction of up to 93% (p<0.0001). With regimen B, there were significant (p<0.0001) improvements in AVCR at a variety of anatomical sites. The ROC analysis demonstrated a significantly higher Az score for the novel regimen compared with regimen A (p<0.002) with inter-neuroradiologist agreement increasing from poor to moderate.
  
  
  CONCLUSIONS
  Significant improvements in visualisation of head and neck arterial vasculature can be achieved with a CT acquisition regimen using low contrast volume and injection timing based on patient specific contrast formula and craniocaudal scan direction.
authors.affiliation: Department of Radiology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia. info@mdct.com.au
authors.forename: Charbel
authors.initials: C
authors.lastname: Saade
authors.forename: Roger
authors.initials: R
authors.lastname: Bourne
authors.forename: Mark
authors.initials: M
authors.lastname: Wilkinson
authors.forename: Michael
authors.initials: M
authors.lastname: Evanoff
authors.forename: Patrick
authors.initials: P
authors.lastname: Brennan
mesh_terms: D000368:Aged; D000792:Angiography / Q000379:methods*; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006257:Head / Q000098:blood supply* / Q000000981:diagnostic imaging; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D009333:Neck / Q000098:blood supply* / Q000000981:diagnostic imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide