Shawn Halpin BMBS, Abstract Co-Author: Nothing to Disclose

Michael W. Bourne BMBS, Presenter: Speaker, General Electric Company Medical Advisory Board, General Electric Company

Raed Alkilani BMBS, Abstract Co-Author: Nothing to Disclose

Michael Booth BSc, Abstract Co-Author: Nothing to Disclose

Jackie Bye BA, Abstract Co-Author: Employee, General Electric Company, Chalfont St Giles, UK

Karen Procknow, Abstract Co-Author: Employee, General Electric Company, Milwaukee, WI

Vincent Adam PhD, Abstract Co-Author: Employee, General Electric Company

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

The CT "brain attack" protocol in acute stroke requires a plain CT scan of the brain, as well as CTA and CTP studies. Up to now, CTA and CTP have been sequentially acquired with a 4cm CTP block. Our purpose is to examine a new technique, acquiring CTA and CTP data simultaneously over an 8cm block, comparing the diagnostic utility, time of examination, and radiation dose of the new technque with the sequential method.

20 consecutive patients, presenting with acute stroke or subarachnoid haemorrhage and suspected vasospasm, were examined using the Volume ShuttleTM protocol. CTA data was extracted from the CTP pass with the best arterial opacification, and processed with a 3D noise reduction filter before being reconstructed as volume rendered and MIP CTA datasets. Radiation dose, in mSv, was calculated from Dose Length Product using the European Guidelines on Quality Criteria for CT. Examination time was recorded. A retrospective comparison was made with 20 similar patients scanned using the sequential method of CTA and a 4cm CTP block with regard to radiation dose and time. The diagnostic utility of 8cm coverage was assessed by 2 experienced neuroradiologists who indepentantly recorded diagnoses from the 1st 4cm of CTP data and the whole 8cm volume.

The radiation dose for Shuttle CTP and CTA was 4.79mSv, with no variation as all parameters are fixed. Radiation dose for sequential CTP/CTA was 7.69-8.01mSv(mean 7.78+/-0.15, p<0.001). Mean dose saving was 2.99mSv. Scan time for Shuttle CTP/CTA was 9-15 minutes shorter than the sequential method. Useful additional information was found in 4 of 20(25%) patients when conparing 8cm versus 4cm CTP.

Simultaneous acquisition of CTA and CTP data over 8cm provides improved diagnostic information with a lower radiation dose and less contrast medium volume than the sequential 4cm method

Reducing exam time, radiation dose and contrast medium load are significant clinical benefits for the acute stroke patient.

Halpin, S, Bourne, M, Alkilani, R, Booth, M, Bye, J, Procknow, K, Adam, V, et al, , et al, , Simultaneous Acquisition of CT Angiography(CTA) and CT Perfusion(CTP) Data with 8cm Coverage: Reduction of Radiation Dose and Clinical Benefit Compared to Sequential Acquisitions over 4cm.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5006807.html