J Cerebrovasc Endovasc Neurosurg.  2015 Mar;17(1):20-26. 10.7461/jcen.2015.17.1.20.

Contrast Extravasation on Computed Tomography Angiography Imitating a Basilar Artery Trunk Aneurysm in Subsequent Conventional Angiogram-Negative Subarachnoid Hemorrhage: Report of Two Cases with Different Clinical Courses

• Cho WH
• Choi HJ
• Nam KH
• Lee JI

• KMID: 1963145
• DOI: http://doi.org/10.7461/jcen.2015.17.1.20

Abstract

Contrast extravasation on computed tomography angiography (CTA) is rare but becoming more common, with increasing use of CTA for various cerebral vascular diseases. We report on two cases of spontaneous subarachnoid hemorrhage (SAH) in which the CTA showed a saccular lesion of the upper basilar trunk suggesting a ruptured aneurysm. However, no vascular lesion was observed on immediate subsequent digital subtraction angiography (DSA). In one case, repeated follow up DSA was also negative. The patient was treated conservatively and discharged with no neurologic deficit. In the other case, the patient showed sudden mental deterioration on the third hospital day and her brain CT showed rebleeding. The immediate follow up DSA showed contrast stagnation in the vicinity of the upper basilar artery, suggestive of pseudoaneurysm. Double stent deployment at the disease segment was performed. Due to the frequent use of CTA, contrast extravasation is an increasingly common observation. Physicians should be aware that basilar artery extravasation can mimic the appearance of an aneurysm.

Keyword

Angiogram-negative; Computed tomography; Basilar artery; Extravasation of contrast media

MeSH Terms

Aneurysm*
Aneurysm, False
Aneurysm, Ruptured
Angiography*
Angiography, Digital Subtraction
Basilar Artery*
Brain
Extravasation of Diagnostic and Therapeutic Materials
Follow-Up Studies
Humans
Neurologic Manifestations
Stents
Subarachnoid Hemorrhage*
Vascular Diseases

Figure

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  Fig. 1 (A) Noncontrast computed tomography (CT) scan on admission shows diffuse subarachnoid hemorrhage in the prepontine cistern and both sylvian fissures. (B) 3-dimensional computed tomography angiography image demonstrates an enhancing abnormal vascularity (arrow). (C) Digital subtraction angiography of the basilar artery acquired in the anteroposterior (left) and lateral (right) views failed to detect the previously seen basilar abnormal structure.

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  Fig. 2 (A) Initial noncontrast computed tomography (CT) scan reveals diffuse subarachnoid hemorrhage in the basal, prepontine, perimesencephalic cistern and both sylvian fissures. (B) Computed tomography angiography axial and (C) sagittal reformatted images showing an enhanced saccular structure with surrounding blood clot on the posterior surface of the basilar artery (arrow). (D) 3-D computed tomography angiography image demonstrating a cylinder-shape, enhancing abnormal structure (arrow). (E) Digital subtraction angiography of the basilar artery acquired 2 hours after the initial CT scan in the anteroposterior (left) and lateral (right) views failed to detect the previously seen basilar abnormal structure.

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  Fig. 3 Digital subtraction angiography of the basilar artery acquired 3 days after a bleeding event, in the oblique view demonstrates the cylinder-shape contrast stagnation in the upper basilar trunk at late arterial phase (arrow).

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  Fig. 4 Follow up digital subtraction angiography acquired 28 days after double stenting. Superselective microcatheter angiography of the left superior cerebellar artery confirms a pseudoaneurysm arising from the small superior cerebellar artery perforating artery (arrow).

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  Fig. 5 Native image of temporary balloon occlusion within the double stents. White arrow shows balloon inflation to achieve decreasing inflow into the pseudoaneurysm.

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  Fig. 6 Follow up digital subtraction angiography performed 11 months after hemorrhage confirmed no contrast stagnation or abnormal vascular lesion with patent stented basilar artery and superior cerebellar arterys.

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