Intraoperative computed tomography angiography with computed tomography perfusion imaging in vascular neurosurgery: feasibility of a new concept

Clinical article

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In vascular neurosurgery, there is a demand for intraoperative imaging of blood vessels as well as for rapid information about critical impairment of brain perfusion. This study was conducted to analyze the feasibility of intraoperative CT angiography and brain perfusion mapping using an up-to-date multislice CT scanner in a prospective pilot series.


Ten patients with unruptured aneurysms underwent intraoperative scanning with a 40-slice sliding-gantry CT scanner. Multimodal CT acquisition was obtained in 8 patients consisting of dynamic perfusion CT (PCT) scanning followed by intracranial CT angiography. Two of these patients underwent CT angiography and PCT 2 times in 1 session as a control after repositioning cerebral aneurysm clips. In another 2 patients, CT angiography was performed alone. The quality of all imaging obtained was assessed in a blinded consensus reading performed by an experienced neurosurgeon and an experienced neuroradiologist. A 6-point scoring system ranging from excellent to insufficient was used for quality evaluation of PCT and CT angiography.


In 9 of 10 PCT data sets, the quality was rated excellent or good. In the remaining case, the quality was rated insufficient for diagnostic evaluation due to major streak artifacts induced by the titanium pins of the head clamp. In this particular case, the quality of the related CT angiography was rated good and sufficient for intraoperative decision making. The quality of all 12 CT angiography data sets was rated excellent or good. In 1 patient with an anterior communicating artery aneurysm, PCT scanning led to a repositioning of the clip because of an ischemic pattern of the perfusion parameter maps due to clip stenosis of an artery. The subsequent PCT scan obtained in this patient revealed an improved perfusion of the related vascular territory, and follow-up MR imaging showed only minor ischemia of the anterior cerebral artery territory.


Intraoperative CT angiography and PCT scanning were shown to be feasible with short acquisition time, little interference with the surgical workflow, and very good diagnostic imaging quality. Thus, these modalities might be very helpful in vascular neurosurgery. Having demonstrated their feasibility, the impact of these methods on patients' outcomes has now to be analyzed prospectively in a larger series.

Abbreviations used in this paper: ACoA = anterior communicating artery; CBF = cerebral blood flow; CBV = cerebral blood volume; DS = digital subtraction; MCA = middle cerebral artery; PCT = perfusion CT; ROI = region of interest; TTP = time to peak.

Article Information

* Drs. Schichor and Rachinger contributed equally to this study.

Address correspondence to: Christian Schichor, M.D., Neurosurgical Clinic, Ludwig-Maximilians-University of Munich, Marchioninistrasse 15, 81377 Munich, Germany. email:

Please include this information when citing this paper: published online October 9, 2009; DOI: 10.3171/2009.9.JNS081255.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    Photograph of the operating room setup. A sliding-gantry 40-multislice CT scanner with an 82-cm bore diameter is installed on rails, which had been mounted into the floor of the operating room. The patient is positioned on a radiolucent adjustable, flexible operating table.

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    A CT angiogram obtained after clipping of a right-sided MCA aneurysm. There are no artifacts caused by trepanation borders. Excellent imaging quality can be seen in the vicinity of the clip, where both branches of the MCA bifurcation are preserved after clipping.

  • View in gallery

    A CT angiogram showing excellent imaging quality, obtained after clipping of a lobulated ACoA aneurysm with 2 clips and a booster clip, as well as 2 clips occluding a right-sided MCA aneurysm.

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    a: Normal PCT after clipping of a right-sided MCA aneurysm. b: A PCT obtained in a patient with an ACoA aneurysm. Analysis of CBV, CBF, and TTP revealed an ischemic perfusion deficit due to unexpected stenosis after clipping. After repositioning of the clip, subsequent PCT showed improved parameters. MIP = maximum intensity projection; MTT = mean transit time.


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