Intradural aneurysm arising from the posterior genu of the cavernous carotid artery mimicking a posterior communicating aneurysm: case report

Coiling ruptured aneurysms arising from the posterior genu of the cavernous internal carotid artery: A report of two cases

INTRODUCTION AND IMPORTANCE

Exceptionally, aneurysms from the posterior genu of the cavernous internal carotid artery (ICA) can rupture, resulting in subarachnoid hemorrhage (SAH). We reported such a case and provided another case with an unruptured aneurysm as a control to confirm the rarity of the ruptured aneurysm from the posterior genu of the cavernous ICA.

CASE PRESENTATION

Case 1: This was a 46-year-old female with SAH. Computed tomography angiography (CTA) and digital subtraction angiography (DSA) confirmed that an aneurysm from the posterior genu of the right cavernous ICA had expanded into the intradural space and ruptured; the aneurysm was coiled completely. Postoperatively, she died from cerebral ischemia due to vasospasm. Case 2: This was a 59-year-old female with SAH. CTA and DSA revealed six aneurysms, including two mirror-like aneurysms from the bilateral anterior communicating artery (AcomA), two tandem aneurysms from the posterior genu of the left cavernous ICA, and two aneurysms from the bilateral anterior cavernous ICAs. After coiling the two tandem aneurysms from the posterior genu of the left cavernous ICA, the bilateral AcomA aneurysms were clipped, and rupture of the right AcomA aneurysm was confirmed. Follow-up CTA showed complete clipping of the bilateral AcomA aneurysms. Her Glasgow Outcome Scale score was 5. Endovascular treatment for residual aneurysms is planned for the future.

CLINICAL DISCUSSION

As shown in these two cases, the aneurysm from the posterior genu of the cavernous ICA can rupture, resulting in SAH; however, the rupture of other aneurysms must be excluded.

CONCLUSION

Once a ruptured aneurysm from the posterior genu of the cavernous ICA was confirmed, EVT was considered an alternative treatment.

Report of intradural aneurysm in the cavernous segment of the internal carotid artery presented with subarachnoid hemorrhage and oculomotor palsy

Background:

Aneurysms of the cavernous segment of the internal carotid artery (ICA) do not usually cause subarachnoid hemorrhage (SAH). We report a patient who presented with this condition due to a ruptured aneurysm located on the posterior genu of the cavernous segment, raising the question of what factors could have led to such evolution.

Case Description:

A 55-year-old male patient presented with sudden, intense thunderstorm headache, associated with complete palsy of the left oculomotor nerve and neck stiffness. Cranial computed tomography (CT) showed no SAH, but showed an expansive process in the sella turcica, consistent with a pituitary macroadenoma. After that, SAH was confirmed by lumbar puncture (Fisher I). Cranial angio-CT revealed an intradural saccular aneurysm in the cavernous segment of the left ICA. The patient underwent cranial microsurgery for cerebral aneurysm clipping. Unlike the normal anatomic pattern, the cavernous segment of the carotid artery in this patient was located in the intradural compartment.

Conclusion:

Intradural rupture of proximal cavernous segment carotid aneurysms is rare. We review the literate for such cases and discuss the possible causes.

MRI location of the distal dural ring plane: anatomoradiological study and application to paraclinoid carotid artery aneurysms

The distal dural ring plane (DDRP) separates the intradural from the extradural paraclinoid internal carotid artery. The purpose of this study was to evaluate its position with MR imaging. The protocol used a T2-weighted sequence in two orthogonal planes: diaphragmatic (DIA-P) and carotid (CAR-P). The DDRP passes through four anatomoradiological reference points (RefP). We developed on a cadaveric model a correlation method supported by correlation lines and angles (CA) projecting the RefP toward the DDRP. RefP were correlated to the DDRP in 65-84% of cases in the DIA-P and 60-76% of cases in the CAR-P. CA were identified and correlated to the DDRP, respectively, in 87% and 60% of cases in the DIA-P, and 60% and 51% of cases in the CAR-P (failure often related to a lack of visibility of just one RefP). A higher tissular contrast in living subjects allowed the identification of CA in 90% and 80% of cases, respectively, in the DIA-P and the CAR-P. We propose that CA, when identified, should be considered as an approximation of the inferior radiological limit of the DDRP curve. In difficult angiographical cases, this MRI protocol could help to locate paraclinoid aneurysms on both sides of the cavernous sinus roof.