BACKGROUND: Whereas mechanical thrombectomy (MT) has become standard-of-care treatment for patients with salvageable brain tissue after acute stroke caused by large-vessel occlusions, the results of MT in patients with medium-vessel occlusions (MEVOs), particularly in the posterior cerebral artery (PCA), are not well known.
METHODS: Using data from the international Stroke Thrombectomy and Aneurysm Registry (STAR), we assessed presenting characteristics and clinical outcomes for patients who underwent MT for primary occlusions in the P2 PCA segment. As a subanalysis, we compared the PCA MeVO outcomes with STAR\'s anterior circulation MeVO outcomes, namely middle cerebral artery (MCA) M2 and M3 segments.
RESULTS: Of the 9812 patients in STAR, 43 underwent MT for isolated PCA MeVOs. The patients\' median age was 69 years (interquartile range 61-79), and 48.8% were female. The median NIH Stroke Scale score was 9 (range 6-17). After recanalization, 67.4% of patients achieved successful recanalization (modified treatment in cerebral infarction score [mTICI] ≥ 2b), with a first-pass success rate of 44.2%, and 39.6% achieved a modified Rankin score of 0-2 at 90 days. Nine patients (20.9%) had died by the 90-day follow-up. In comparison with M2 and M3 MeVOs, there were no differences in presenting characteristics among the three groups. Patients with PCA MeVOs were less likely to undergo intra-arterial thrombolysis (4.7% PCA vs. 10.1% M2 vs. 16.2% M3, p = 0.046) or to achieve successful recanalization (mTICI ≥ 2b, 67.4%, 86.7%, 82.3%, respectively, p < 0.001); however, there were no differences in the rates of successful first-pass recanalization (44.2%, 49.8%, 52.3%, respectively, p = 0.65).
CONCLUSIONS: We describe the STAR experience performing MT in patients with PCA MeVOs. Our analysis supports that successful first-pass recanalization can be achieved in PCA MEVOs at a rate similar to that in MCA MeVOs, although further study and possible innovation may be necessary to improve successful PCA MeVO recanalization rates.

Previous studies have reported various anatomical differences in the cerebral artery between healthy subjects and patients with posterior circulation cerebral infarction. In particular, basilar artery angulation has been associated with posterior circulation cerebral infarction. We compared anatomical variations and the degree of anterior and lateral vertebrobasilar artery angulation and deviation to compare the incidence of cerebral infarction of healthy subjects and patients with posterior circulation cerebral infarction. We compared basilar artery anatomy using brain magnetic resonance angiography in 97 patients who underwent brain magnetic resonance angiography during health checkups at our hospital and in 92 patients diagnosed with posterior circulation cerebral infarction between 2012 and 2022. Anatomical variations, including fetal-type posterior cerebral artery, hypoplastic P1 segment, vertebrobasilar dolichoectasia, and dominant vertebral artery, as well as the degree of anterior and lateral deviation and angulation, were evaluated. Correlations between these variations and the occurrence of cerebral infarction were analyzed. The prevalence of hypoplastic P1 was significantly differences in patients with posterior circulation cerebral infarction (odds ratio: 5.655). Furthermore, patients with posterior circulation cerebral infarction exhibited more acute anterior and lateral angulation, as well as lateral deviation. Hypoplastic P1 and more acute anterior or lateral angulation of the vertebrobasilar artery are associated with increased frequency of cerebral infarction.

OBJECTIVE: To describe a case of replaced posterior cerebral artery (PCA) in which all branches of the PCA arose from the anterior choroidal artery (AChA) with an early branching temporal artery.
METHODS: An 83-year-old man with cerebral infarctions underwent cranial magnetic resonance (MR) imaging and MR angiography using a 3-Tesla scanner. MR angiography was performed using a standard 3-dimensional time-of-flight technique.
RESULTS: A large anomalous artery arose from the supraclinoid segment of the right internal carotid artery (ICA) and supplied all branches of the right PCA, mimicking fetal-type PCA. The temporal branch arose from the proximal segment of this artery. In MR angiographic source images, a tiny artery arose from the right ICA proximal to the origin of the anomalous artery, indicating a hypoplastic right posterior communicating artery (PCoA). Thus, we concluded that the anomalous artery was a replaced PCA; all branches of the PCA arose from the AChA.
CONCLUSIONS: We present a case involving a replaced PCA with an early branching temporal artery, as seen on MR angiography. Careful observation of MR angiographic source images is useful for identifying small arteries. To our knowledge, this is the first report of this combined variation in the relevant English-language literature.

Artery of Percheron (AOP) is an uncommon anatomical variation in the posterior circulation neurovasculature. It is a single artery arising from P1 segment of posterior cerebral artery (PCA) which supplies bilateral paramedian thalami and the rostral midbrain and as a result, occlusion of it leads to bilateral thalamic and mesencephalic infarction. Due to very low incidence (ranges from 0.1% to 2% of all ischemic strokes) and varied presentation, the diagnosis of AOP infarction requires strong clinical and radiological suspicion and hence, AOP infarction is often missed and patients are rarely thrombolysed. Here we discuss a patient with acute altered sensorium who recovered completely in short time following treatment with intra-venous thrombolysis for bilateral medial thalamic ischemic stroke due to AOP occlusion.

BACKGROUND: The fetal-type posterior cerebral artery (PCA) is defined as a variant anatomy in which the posterior communicating artery (PCOM) is larger than the hypoplastic or aplastic P1 segment of the PCA. The authors present the novel case of a patient with a duplicated right PCA in parallel with fetal-type and conventional PCAs supplying adjacent components of the PCA cerebral territory.
METHODS: A 59-year-old woman presented with a modified Fisher Scale score 4 subarachnoid hemorrhage. A right irregular PCOM aneurysm that measured 9.5 mm × 4.5 mm × 4.5 mm arose from the base of a variant branch supplying a portion of the PCA, rather than a conventional PCOM, and was found on digital subtraction angiography. Following endovascular coil embolization, the patient was discharged home.
CONCLUSIONS: The fetal-type variant has implications for thromboembolic events. If an embolism occludes the anterior circulation in a patient with a fetal-type PCA, it may result in an infarct in the PCA territory. Awareness of cerebral arterial anatomy, including an atypical collateral supply, informs a treating team\'s latitude in tolerance of which sites must be preserved and which can be safely sacrificed. https://thejns.org/doi/10.3171/CASE23735.

OBJECTIVE: Posterior cerebral artery involvement (PCAi) has been identified as an important factor related to poor prognosis in moyamoya disease (MMD). This study summarized the characteristics of children with MMD and PCAi, clarified the clinical course, identified prognostic predictors, and investigated the long-term effect of encephaloduroarteriosynangiosis for posterior circulation (EDAS-p).
METHODS: We retrospectively reviewed all our pediatric MMD cases with follow-up angiograms from November 2003 to December 2016. PCAi was classified as early-onset at initial diagnosis and delayed-onset after anterior circulation revascularization. Multivariable data including clinical features, radiographic findings, and surgical outcomes were analyzed.
RESULTS: Among 570 children with MMD, 246 (43.2%) had PCAi, with 176 (30.9%) classified as early-onset PCAi. During a median follow-up period of 10 years, 17.8% (70/394) of patients without initial PCAi developed delayed-onset PCAi. The median time to detection of a new PCA lesion was 15.5 (range 7-110) months from initial diagnosis, with a median age of 10.5 (3-22). Younger age at onset, familial occurrence, advanced Suzuki stages, and preoperative infarctions were predictors of delayed-onset PCAi. EDAS-p was performed on 294 hemispheres of 195 patients with PCAi. Stroke-free survival was significantly higher in the EDAS-p group than in the non-EDAS-p group (99.0% vs 90.2%; p < 0.001 [Breslow test]; p = 0.001 [log-rank test]; median follow-up: 101 months).
CONCLUSIONS: PCAi is not uncommon in children with MMD, underscoring the need for long-term close clinical monitoring, especially in patients with high-risk factors for PCA progression. EDAS-p may be a safe and effective procedure for preventing subsequent stroke in children with MMD and PCAi.

Anomalous vascular variants pose unique challenges in clinical management, especially in the context of neuroendovascular intervention. We present a case report detailing an extremely rare anatomic variant involving the left anterior choroidal artery, which arises proximal to the fetal posterior communicating artery. Our patient presented with confusion and speech abnormalities following a benzodiazepine overdose. Subsequent computed tomography of the head revealed an aneurysm originating from the left supraclinoid carotid artery. This aneurysm was located 2 mm more proximal to the origin of the left posterior communicating artery and was initially misidentified as originating from the left posterior communicating artery due to its proximity. Further diagnostic cerebral angiography revealed an extremely rare anatomical variant where the left anterior choroidal artery anomalously arose proximal to a fetal posterior communicating artery, with the aneurysm being correctly identified as arising from the left anterior choroidal artery. The patient underwent successful detoxification and has since shown remarkable improvement, with plans for elective endovascular flow diversion treatment under dual antiplatelet therapy. Considering the critical role of the anterior choroidal artery in supplying vital cerebral structures, awareness of such variants is paramount to prevent inadvertent vascular injury and optimize patient outcomes. This case highlights the necessity of meticulous pre-procedural imaging and multidisciplinary collaboration in managing neurovascular anomalies effectively.

OBJECTIVE: Aneurysms of the posterior cerebral circulation constitute a burdensome condition with high mortality and morbidity. In the modern era, there has been a trend toward favoring an endovascular approach over microsurgery for aneurysm cases. Nevertheless, this transition has yet to be mirrored in low-to-middle-income countries where endovascular therapy may not be widely available. Herein, we aim to illustrate our experience treating these challenging conditions in patients from low-income backgrounds and discuss the relevance of the clinical setting in the treatment decision.
METHODS: The authors conducted a retrospective review of the health records of patients who received microsurgical treatment for aneurysms in the posterior circulation, including the basilar artery (BA), posterior cerebral artery (PCA), and posterior inferior cerebellar artery (PICA) in an institution providing treatment to people of low-income backgrounds. Epidemiological data, microsurgical technique, and neurological function were retrieved and analyzed.
RESULTS: Surgical clipping was employed for 12 patients (75% female) harboring 15 aneurysms (87% in the posterior circulation and 62% ruptured at presentation). Aneurysms were predominately located in the BA (69%), followed by the PCA (15%) and PICA (15%). Among neurological complications, 25% of patients developed oculomotor nerve palsy. The mortality rate was 17% owing to complications such as cerebral vasospasm, infarction, and severe intracranial hypertension. At the 6-month follow-up, 90% of patients had a good clinical outcome (modified Rankin scale scores of 0-2).
CONCLUSIONS: The present case series illustrates the manifest role of microsurgical techniques for posterior circulation aneurysms, particularly in a scenario where endovascular techniques are not easily accessible. Importantly, this clinical setting pressure could exhort trainees to strive for microsurgical mastery and gain a competitive advantage.

OBJECTIVE: The present case report aims to describe the rare coexistence of three variants of the cerebral arterial system diagnosed by computed tomography angiography (CTA).
METHODS: A retrospective study on head and neck CTAs was performed on a Greek adult population from the Department of Radiology, University Hospital of Larissa. An interesting case of an 80-year-old male was further investigated.
RESULTS: The cerebral arterial circle presented with a combination of three variations. The left anterior cerebral artery (ACA) was fenestrated 1.4 mm proximally to the anterior communicating artery formation. The left posterior cerebral artery (PCA) was also fenestrated, 5.5 mm distally to its origin from the basilar artery. Lastly, the right PCA originated from the ICA supraclinoid segment.
CONCLUSIONS: This case report highlights an unusual coexistence of A1 and P1 segments fenestration with a fetal PCA, resulting in a unique cerebral circle. A1 segment fenestration has been previously reported as rare, while the PCA fenestration as extremely rare variant. Awareness of these rare variations could aid interventionists in their preoperative assessments.

UNASSIGNED: Eventually, 108 consecutive patients received 174 surgeries were enrolled, experienced new or expanded infarction occured in 13 (7.47%) surgeries, which showed higher Suzuki stage on the non-operative side, more posterior cerebral artery (PCA) involvement, and more intraoperative hypotension compared to those without infarction(p < .05). The Suzuki stage on the non-operative side had the highest area under the curve (AUC) of 0.737, with a sensitivity of 0.692 and specificity of 0.783. Combination of the three factors showed better efficiency, with an AUC of 0.762, a sensitivity of 0.692, and a specificity of 0.907.
UNASSIGNED: Revascularization was a safe option for patients with MMD, higher Suzuki stage on the non-operative side, PCA involvement, and intraoperative hypotension might be the risk factors for new or expanded infarction after revascularization in patients with MMD.