J Cerebrovasc Endovasc Neurosurg.  2015 Dec;17(4):324-330. 10.7461/jcen.2015.17.4.324.

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: 2150971
• DOI: http://doi.org/10.7461/jcen.2015.17.4.324

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 an upper basilar trunk saccular lesion suggesting ruptured aneurysm. However, immediate subsequent digital subtraction angiography (DSA) failed to show a vascular lesion. In one case, repeated follow up DSA was also negative. The patient was treated conservatively and discharged without any 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 stents 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 SAH; Computed tomography angiography; Basilar artery; Contrast extravasation

MeSH Terms

Aneurysm*
Aneurysm, False
Aneurysm, Ruptured
Angiography*
Angiography, Digital Subtraction
Basilar Artery*
Brain
Follow-Up Studies
Humans
Neurologic Manifestations
Stents
Subarachnoid Hemorrhage*
Vascular Diseases

Figure

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

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  Fig. 2 Case 2. (A) Initial noncontrast CT scan reveals diffuse subarachnoid hemorrhage (SAH) in the basal, prepontine, perimesencephalic cistern and both sylvian fissures. (B) Computed tomography angiography (CTA) 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 CTA image demonstrating a cylinder-shape, enhancing abnormal structure (arrow). (E) Digital subtraction angiography (DSA) of the basilar artery acquired 2 hours later from initial CT scan in the anteroposterior (left) and lateral (right) views fail to detect the previously seen basilar abnormal structure.

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  Fig. 3 Case 2. Digital subtraction angiography (DSA) of the basilar artery acquired 3 days after bleeding event, in the oblique view demonstrate the cylinder-shape contrast stagnation in the upper basilar trunk at late arterial phase (arrow).

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  Fig. 4 Case 2. Follow up digital subtraction angiography (DSA) acquired 28 days after double stenting. Superselective microcatheter angiography of left superior cerebellar artery confirms a pseudoaneurysm arising from small superior cerebellar artery (SCA) perforating artery (arrow).

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  Fig. 5 Case 2. Native image of temporary balloon occlusion within the double stents. White arrow shows balloon inflation to achieve decreasing of inflow into the pseudoaneurysm.

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  Fig. 6 Case 2. Follow up digital subtraction angiography (DSA) done 11 months after hemorrhage confirmed no contrast stagnation or abnormal vascular lesion with patent stented basilar artery and superior cerebellar artery (SCA)s.

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