title: 3D CT cerebral angiography technique using a 320-detector machine with a time-density curve and low contrast medium volume: comparison with fixed time delay technique.
abstract: OBJECTIVE
  To describe a cerebral computed tomography angiography (CTA) technique using a 320-detector CT machine and a small contrast medium volume (35 ml, 15 ml for test bolus). Also, to compare the quality of these images with that of the images acquired using a larger contrast medium volume (90 or 120 ml) and a fixed time delay (FTD) of 18 s using a 16-detector CT machine.
  
  
  METHODS
  Cerebral CTA images were acquired using a 320-detector machine by synchronizing the scanning time with the time of peak enhancement as determined from the time-density curve (TDC) using a test bolus dose. The quality of CTA images acquired using this technique was compared with that obtained using a FTD of 18 s (by 16-detector CT), retrospectively. Average densities in four different intracranial arteries, overall opacification of arteries, and the degree of venous contamination were graded and compared.
  
  
  RESULTS
  Thirty-eight patients were scanned using the TDC technique and 40 patients using the FTD technique. The arterial densities achieved by the TDC technique were higher (significant for supraclinoid and basilar arteries, p < 0.05). The proportion of images deemed as having "good" arterial opacification was 95% for TDC and 90% for FTD. The degree of venous contamination was significantly higher in images produced by the FTD technique (p < 0.001%).
  
  
  CONCLUSIONS
  Good diagnostic quality CTA images with significant reduction of venous contamination can be achieved with a low contrast medium dose using a 320-detector machine by coupling the time of data acquisition with the time of peak enhancement.
authors: Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, Liverpool, UK.
authors: K
authors: K
authors: Das
authors: Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, Liverpool, UK. Electronic address: Shubhabrata.Biswas@thewaltoncentre.nhs.uk.
authors: S
authors: S
authors: Biswas
authors: Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, Liverpool, UK.
authors: S
authors: S
authors: Roughley
authors: Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, Liverpool, UK.
authors: M
authors: M
authors: Bhojak
authors: Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, Liverpool, UK.
authors: S
authors: S
authors: Niven
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography / Q000295:instrumentation / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
chemical_list: D003287:Contrast Media