Subtraction Helical CT Angiography of Intra- and Extracranial Vessels
Technical Considerations and Preliminary Experience
Vijayam K. Jayakrishnana,
Philip M. Whiteb,
Douglas Aitkena,
Paul Cranec,
Alex D. McMahond and
Evelyn M. Teasdalea
a Department of Neuroradiology, Institute of Neurological Sciences, Glasgow
b Department of Neuroradiology, Western General Hospital, Edinburgh
c Philips Medical Systems, UK
d Robertson Center for Biostatistics, Glasgow, Scotland
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FIG 1. Image processing for subtraction CTA.
A, Three-dimensional model of the skull is created from precontrast dataset.
B, MIP created from the contrast-enhanced dataset.
C, Subtracted image after removing A from B, before any editing.
D, Subtracted image with minimal editing.
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FIG 2. The restraining device is molded around the back of the patient’s head and the angles of the jaw. Inset shows the valve for the suction connection
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FIG 3. MIP images.
A, MIP CTA image after editing shows residual bone at the base of the skull.
B, MIP DSCTA image better shows the basilar artery, its branches. and the aneurysm.
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FIG 4. MIP images.
A, MIP CTA image shows that bone obscures the detail of the distal vertebral arteries.
B, MIP DSCTA image clearly shows clear the vertebral arteries and the posterior inferior cerebellar arteries.
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