Subtraction 3D CT Angiography with the Orbital Synchronized Helical Scan Technique for the Evaluation of Postoperative Cerebral Aneurysms Treated with Cobalt-Alloy Clips

BACKGROUND AND PURPOSE: CT angiography (CTA) has been used for the evaluation of intracranial aneurysms and recently has been applied to assess postoperative aneurysms treated with titanium-alloy clips. We investigated the clinical usefulness of subtraction CTA by using the orbital synchronized helical scan technique (OSHST) for evaluating intracranial aneurysms surgically treated with cobalt-alloy clips. MATERIALS AND METHODS: We scanned an agar gel phantom with a cobalt-alloy clip mounted in the center by using subtraction CT with and without OSHST. Eighteen patients (20 aneurysms) who underwent surgery with cobalt-alloy clips were postoperatively evaluated with subtraction CTA with OSHST, and the results were compared with those from digital subtraction angiography. Two neuroradiologists independently evaluated the 3D CTA images and source images with and without subtraction for the presence of residual flow in the aneurysm and stenotic change in parent or neighboring arteries. RESULTS: For the phantom study, significantly fewer artifacts from clips were noted on images obtained by using subtraction CT with OSHST than on those obtained without OSHST. For the clinical study, subtraction CTA with OSHST also showed fewer clip artifacts than did conventional CTA. Image quality was poor, and we were unable to diagnose residual neck for 5% (1/20) with subtraction CTA with OSHST and 75% (15/20) with conventional CTA. For evaluation of adjacent vessels, image quality was poor for none (0/20) with subtraction CTA with OSHST and for 55% (11/20) with conventional CTA. For subtraction CTA with OSHST, sensitivity in detecting residual neck was 1.0, and specificity was 0.94. For conventional CTA, sensitivity and specificity were both 0.25. CONCLUSIONS: OSHST is a useful technique for subtracting cobalt-alloy clips, and subtraction CTA with OSHST is available for evaluating aneurysms after clipping with cobalt-alloy clips.

[1]  G. Rinkel,et al.  Multislice computed tomography angiography screening for new aneurysms in patients with previously clip-treated intracranial aneurysms: Feasibility, positive predictive value, and interobserver agreement. , 2006, Journal of neurosurgery.

[2]  H. Kinouchi,et al.  Postoperative three-dimensional CT angiography after cerebral aneurysm clipping with titanium clips: detection with single detector CT. Comparison with intra-arterial digital subtraction angiography. , 2006, Clinical radiology.

[3]  K Arita,et al.  Subtracted 3D CT angiography for evaluation of internal carotid artery aneurysms: comparison with conventional digital subtraction angiography. , 2006, AJNR. American journal of neuroradiology.

[4]  L. Regli,et al.  Comparison of multislice computerized tomography angiography and digital subtraction angiography in the postoperative evaluation of patients with clipped aneurysms. , 2006, Journal of neurosurgery.

[5]  H. Mori,et al.  Limitations of three-dimensional reconstructed computerized tomography angiography after clip placement for intracranial aneurysms. , 2005, Journal of neurosurgery.

[6]  A. Algra,et al.  Follow-up screening after subarachnoid haemorrhage: frequency and determinants of new aneurysms and enlargement of existing aneurysms. , 2005, Brain : a journal of neurology.

[7]  C. Truwit,et al.  Multi‐slice computed tomography angiography in the detection of residual or recurrent cerebral aneurysms after surgical clipping , 2004, Acta radiologica.

[8]  P. Bossuyt,et al.  Yield of screening for new aneurysms after treatment for subarachnoid hemorrhage , 2004, Neurology.

[9]  G. D. den Heeten,et al.  Subtraction helical CT angiography of intra- and extracranial vessels: technical considerations and preliminary experience--rediscovery of matched mask bone elimination? , 2003, AJNR. American journal of neuroradiology.

[10]  T Kirino,et al.  Risk of Aneurysm Recurrence in Patients With Clipped Cerebral Aneurysms: Results of Long-Term Follow-Up Angiography , 2001, Stroke.

[11]  H. Venema,et al.  CT angiography of the circle of Willis and intracranial internal carotid arteries: maximum intensity projection with matched mask bone elimination-feasibility study. , 2001, Radiology.

[12]  J. Ausman,et al.  What percentage of surgically clipped intracranial aneurysms have residual necks? , 2000, Neurosurgery.

[13]  S. Kuribayashi,et al.  Subtraction CT angiography with controlled-orbit helical scanning for detection of intracranial aneurysms. , 1998, AJNR. American journal of neuroradiology.

[14]  E Klotz,et al.  Bone-subtraction Ct Angiography for the Evaluation of Intracranial Aneurysms Materials and Methods , 2004 .

[15]  M. V. van Leeuwen,et al.  Minimizing clip artifacts in multi CT angiography of clipped patients. , 2006, AJNR. American journal of neuroradiology.