Bone-Subtraction CT Angiography for the Evaluation of Intracranial Aneurysms
B.F. Tomandla,
T. Hammenb,
E. Klotzd,
H. Dittd,
B. Stemperb and
M. Lellc
a Division of Neuroradiology, University of Erlangen-Nuremberg, Erlangen, Germany
b Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany
c Institute of Diagnostic Radiology, University of Erlangen-Nuremberg, Erlangen, Germany
d Siemens Medical Solutions, Erlangen, Germany
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Fig 1. Illustration of the bone-removal process.
A, Sagittal multiplanar reformation of the data after bone removal shows the contrast-enhanced vascular structures (arrows) as well as brain tissue.
B, Sagittal maximum intensity projection image (15-mm thickness) demonstrates the intraosseous parts of the internal carotid artery (short arrow) as well as the origin of the ophthalmic artery (long arrow).
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Fig 2. Different qualities of bone removal, anterior-inferior view. Note the visibility of the origin of the ophthalmic artery in both images (arrowheads).
A, "Excellent" bone removal without artifacts. There is a small aneurysm of the right middle cerebral artery (arrow).
B, "Moderate" result with remnants of bone (arrows) because of movement of the patient during one of the scans. The arteries within the skull base are still visible. There is a small aneurysm of the anterior communicating artery (arrow).
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Fig 3. Optimal visualization of the ophthalmic artery (arrowheads) of the right ICA in this patient with a large aneurysm of the ICA from a lateral view.
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Fig 4. Prominent cavernous sinus (arrowheads).
A, 3D volume-rendered image with high opacity and shading does not allow evaluation of the intracavernous part of the left ICA completely on this medial view.
B, Transparent (low-opacity) volume-rendered image allows for a good evaluation of the intracavernous portion of the ICA (arrow).
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Fig 5. Aneurysm of the left infraclinoidal ICA, left-superior view.
A, On standard CT angiography the aneurysm is hardly visible (arrow) due to obscuration by the anterior clinoid process.
B, Bone-subtraction CT angiography (BSCTA) clearly shows the complete shape of the aneurysm (arrow).
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Fig 6. Comparison of digital subtraction angiography (DSA), 3D DSA and BSCTA. Patient with a large aneurysm of the right ICA (arrows), right anterior oblique view.
A, DSA.
B, 3D DSA, direct volume rendering.
C, BSCTA. The cavernous sinus does not disturb the interpretation of the image (arrowheads).
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Fig 7. Use of BSCTA for therapy planning of an intracavernous aneurysm of the left ICA (arrows).
A, BSCTA, lateral view of the left ICA.
B, DSA, lateral view of the left ICA.
C, Transparent (low-opacity) volume rendering allows visualization of the borders of the aneurysm’s broad neck (arrowheads) from an anterior view, which is useful for therapy planning. This aneurysm was finally treated by means of stent-protected coiling.
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