Contrast extravasation on computed tomographic angiography mimicking a basilar artery aneurysm in angiogram-negative subarachnoid hemorrhage: report of 2 cases

A Systematic Review and Case Illustrations of Misdiagnosing Intracranial Aneurysms

Modern neuroimaging methods do not completely rule out false diagnoses of intracranial aneurysms which can lead to an unwarranted operation associated with risks of complications. However, surgical interventions for falsely diagnosed aneurysms are quite rare. The purpose of this study is to demonstrate two clinical cases of false-positive aneurysms and a systematic review of the literature dedicated to the incidence and etiology of false-positive aneurysms, identifying risk factors associated with false-positive aneurysms. A literature search in two databases (PubMed and Web of Science) using keywords "mimicking an intracranial aneurysm", "presenting as an intracranial aneurysm", "false positive intracranial aneurysms", and "neurosurgery" was conducted. A total of 243 papers were found in the initial search in two databases. Sixteen papers (including 20 patients) were included in the final analysis. There were 10 women and 10 men. The most common location of false-positive aneurysms was the bifurcation of the middle cerebral artery (MCA). In the posterior circulation, false-positive aneurysms were identified either on the basilar artery, or at the vertebro-basilar junction. The main causes of false intracranial aneurysm diagnosis included artery occlusion with vascular stump formation, infundibular widening, fenestration, arterial dissection, contrast extravasation, and venous varix. In conclusion, summarizing the results of our analysis, we can say that surgical interventions for false-positive aneurysms are an underestimated problem in vascular neurosurgery. Despite extremely rare published clinical observations, the actual frequency of erroneous surgical interventions for false-positive aneurysms is unknown.

Contrast extravasation from basilar artery without aneurysm formation on digital subtraction angiography in computed tomography angiogram-negative subarachnoid hemorrhage: A case report

Background:

The causes of angiogram-negative subarachnoid hemorrhage (SAH) on initial angiography, which accounts for 10–30% of spontaneous SAH, are heterogeneous and still unclear. We report a case of nonaneurysmal SAH, in which initial computed tomographic angiography (CTA) showed no source of bleeding, but the subsequent digital subtraction angiography (DSA) revealed contrast extravasation from the basilar artery without aneurysms.

Case Description:

A 67-year-old woman with a medical history of hypertension presented as SAH of World Federation of Neurological Surgeons Grade II. CTA on admission did not show any cause of bleeding and DSA was subsequently performed to show contrast extravasation from a perforator of the middle third of the basilar artery without aneurysms during the subsequent DSA, resulting in profound deterioration SAH and neurological status. The patient was conservatively treated. Follow-up DSAs on days 2 and 16 showed no source of bleeding as well.

Conclusion:

Although the precise cause of bleeding in this case is uncertain, SAH might be caused by local dissection of the basilar artery perforator, and the bleeding site might heal spontaneously without forming of a pseudoaneurysm.

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

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.

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

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.