A Systematic Review and Case Illustrations of Misdiagnosing Intracranial Aneurysms

Abstract

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.

Keywords: clipping; false-positive diagnosis; intracranial aneurysm; masquerading; mimicking.

Figure 1. PRISMA flow chart depicting the process of study selection

PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses

Figure 2. Illustrative Case 1

A, B, C - different projections on preoperative 3D CTA, aplasia of the left A1 segment had been suspected; D - intraoperative view of the dilated distal part of the left A1 segment (red arrow) mimicking an aneurysm, both A2 segments and the left recurrent branch of Heubner are visualized, as well. CTA: computed tomography angiography The figure was created by the authors.

Figure 3. Illustrative Case 2

А, В - axial CTA (A) and 3D CTA (B) in a mixed arterio-venous phase depicting two aneurysms: tiny left A1 segment aneurysm (blue arrow) and small MCA bifurcation aneurysm (big red arrow), a venous branch (small red arrows) traversing the aneurysm site is recognizable as well; С - intraoperative view showing dilated vein (small red arrows) entering the spheno-parietal sinus (big red arrow), lying close to the MCA bifurcation, no aneurysms were found at this site, only A1 segment aneurysm was clipped. MCA: middle cerebral artery; CTA: computed tomography angiography The figure was created by the authors.