Mechanisms of Stroke in Patients with Fetal Posterior Cerebral Artery

Initial and follow-up high-resolution vessel wall MRI study of spontaneous cervicocranial artery dissection

OBJECTIVES

To explore the factors associated with ischemic stroke secondary to spontaneous cervicocranial artery dissection (sCCAD) and evaluate the initial imaging markers related to outcomes.

METHODS

Initial and follow-up high-resolution vessel wall MRI (VW-MRI) in consecutive patients with sCCAD were retrospectively analyzed. The associations of clinical and imaging factors and variants of the circle of Willis (COW) with ischemic stroke were evaluated using binary logistic regression analyses. The anatomical outcomes were categorized as complete, partial, and no remodeling based on changes of the vessel wall and lumen. Ordinal logistic regression analysis was used to assess associations between initial features and outcomes.

RESULTS

A total of 115 dissected arteries (79 strokes, 36 non-strokes) were detected in 103 patients. Follow-up VW-MRI was available in 46 patients (44.7%, with 51 vessels), with a median interval of 8.5 months. Pseudoaneurysm (odd ratio [OR], 0.178; 95% confidence interval [CI], 0.039-0.810; p = 0.026) tended to rarely cause ischemic stroke, while intraluminal thrombus (OR, 5.558; 95% CI, 1.739-17.765; p = 0.004), incomplete COW (OR, 9.309; 95% CI, 2.122-40.840; p = 0.003), and partial complete COW (OR, 4.463; 95% CI, 1.211-16.453; p = 0.025) were independently associated with stroke occurrence. Furthermore, the presence of double lumen (OR, 5.749; 95% CI, 1.358-24.361; p = 0.018) and occlusion (OR, 12.975; 95% CI, 3.022-55.645; p = 0.001) were associated with no remodeling of sCCAD.

CONCLUSIONS

Multiple initial factors were found to be related to stroke occurrence and anatomical outcomes of sCCAD. High-resolution VW-MRI may provide valuable insights into the pathophysiology and evolution of sCCAD.

CLINICAL RELEVANCE STATEMENT

Initial and follow-up high-resolution vessel wall MRI may help elucidate the pathophysiology of spontaneous cervicocranial artery dissection and provide important insights into the evolution and further facilitate the optimal management of patients with spontaneous cervicocranial artery dissection.

KEY POINTS

• Clinical and imaging factors, as well as the status of primary collateral circulation, are associated with ischemic stroke secondary to spontaneous cervicocranial artery dissection. • The follow-up high-resolution vessel wall MRI provides valuable insights into the long-term evolution and anatomical outcomes of spontaneous cervicocranial artery dissection. • The high-resolution vessel wall MRI features related to ischemic stroke and anatomical outcomes may further facilitate the optimal management of patients with spontaneous cervicocranial artery dissection.

Functional connectivity interacts with visual perceptual learning for visual field recovery in chronic stroke

A reciprocal relationship between perceptual learning and functional brain changes towards perceptual learning effectiveness has been demonstrated previously; however, the underlying neural correlates remain unclear. Further, visual perceptual learning (VPL) is implicated in visual field defect (VFD) recovery following chronic stroke. We investigated resting-state functional connectivity (RSFC) in the visual cortices associated with mean total deviation (MTD) scores for VPL-induced VFD recovery in chronic stroke. Patients with VFD due to chronic ischemic stroke in the visual cortex received 24 VPL training sessions over 2 months, which is a dual discrimination task of orientation and letters. At baseline and two months later, the RSFC in the ipsilesional, interhemispheric, and contralesional visual cortices and MTD scores in the affected hemi-field were assessed. Interhemispheric visual RSFC at baseline showed the strongest correlation with MTD scores post-2-month VPL training. Notably, only the subgroup with high baseline interhemispheric visual RSFC showed significant VFD improvement following the VPL training. The interactions between the interhemispheric visual RSFC at baseline and VPL led to improvement in MTD scores and largely influenced the degree of VFD recovery. The interhemispheric visual RSFC at baseline could be a promising brain biomarker for the effectiveness of VPL-induced VFD recovery.

Duplicated fetal posterior cerebral artery in a patient with a ruptured fetal posterior cerebral artery aneurysm: a cerebrovascular variant

BACKGROUND

The most common neurovascular variant is the fetal posterior cerebral artery (FPCA), in which the P1 branch is absent or hypoplastic, and the majority of P2 supply is derived from the anterior circulation. While there are reports of hyperplastic anterior choroidal arteries (AChA) with supply to the temporo-occipital and calcarine regions, no reports of a duplicated FPCA exist.

METHODS

This case report describes a patient with a ruptured right FPCA aneurysm. Digital subtraction angiogram (DSA) revealed an artery with origin distal to the FPCA associated with the aneurysm. This was not consistent with a typical AChA. The FPCA associated with the aneurysm had the typical origin, course, and supply of a FPCA. The distal FPCA had a similar course of a typical FPCA with significant supply to the typical PCA territory. The patient underwent successful clipping of the aneurysm, and the duplicated FPCA was identified during the craniotomy.

RESULTS

The features of this duplicate FPCA, which has not been previously described, are discussed in comparison to another variant, the hyperplastic, anomalous AChA. The artery described in this report does not fit the typical criteria of this AChA variant. Therefore, the authors outline this variant as a duplicated FPCA.

CONCLUSION

Recognition of variant cerebrovascular anatomy is vital to neurosurgeons and interventional neuroradiology specialists. FPCA aneurysms require special management considerations and are often more challenging to treat. This report discusses a duplicated FPCA. To our knowledge, this is the first description of this variant. A duplicated FPCA carries important management considerations in the management of neurovascular pathology.

Mechanical thrombectomy for acute fetal posterior cerebral artery occlusion with a hidden unruptured cerebral aneurysm: illustrative case

BACKGROUND

Fetal posterior cerebral artery occlusion is rare and often presents with severe neurological symptoms. Although acute recanalization therapy is commonly used for cerebral vessel occlusion, unruptured cerebral aneurysms can be hidden distal to the occluded vessels.

OBSERVATIONS

An 87-year-old man presented with consciousness disturbance and right hemiparesis. The authors diagnosed left fetal posterior cerebral artery occlusion and performed mechanical thrombectomy. A stent retriever was deployed from the middle cerebral artery M1 segment across the mural thrombus of the internal carotid artery. After the first pass, the fetal posterior cerebral artery remained occluded, with confirmation of a contrast effect around the thrombus. Because the anatomical course of the fetal posterior cerebral artery was unidentified, the procedure was stopped. At 1-week recovery, magnetic resonance imaging revealed complete recanalization and a fetal posterior cerebral artery aneurysm hidden within the occluded site. Blood flow was directed to the aneurysm, and the thrombus within the aneurysm simultaneously occluded the fetal posterior cerebral artery.

LESSONS

To avoid critical complications following mechanical thrombectomy for fetal posterior cerebral artery occlusion, hidden aneurysms should be suspected when a “fried egg–like” contrast effect is observed around the thrombus.