Anatomical differences of the vertebrobasilar artery between normal subjects and patients with cerebral infarction.

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.

Successful Thrombolysis in Artery of Percheron Infarction: Grabbed an Extremely Rare Opportunity.

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.

Clinical Course, Therapy, and Long-Term Outcomes of Children With Moyamoya Disease and Posterior Cerebral Artery Involvement.

BACKGROUND AND OBJECTIVES: 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). DISCUSSION: 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.

Fenestration of the anterior and posterior cerebral arteries in coexistence with a contralateral posterior cerebral artery of fetal origin.

PURPOSE: 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.

Association between cerebral artery stenosis and depressive symptoms in elderly patients.

OBJECTIVE: To examine the association between cerebral artery stenosis and depressive symptoms in elderly patients. METHODS: The study participants were 365 patients aged ≥65 years who visited the psychiatric outpatient clinic, Samsung Medical Center between January 1, 2000, and December 31, 2019, and were diagnosed with depressive disorder. They had brain imaging tests including magnetic resonance angiography (MRA), psychological evaluations including the 15-item Geriatric Depression Scale (GDS-15), and lab tests. Individuals' cerebral artery stenosis was identified and the association with significant depressive symptoms was examined. RESULTS: Of the 365 subjects, 108 had at least one location of cerebral artery stenosis (29.6 %). The mean score of GDS-15 in the stenosis group was 8.1 (SD, 3.8), higher than the mean GDS-15 score of 6.5 (SD, 4.0) for the group without stenosis (p < 0.001). Compared to no middle cerebral artery (MCA) stenosis, having MCA stenosis was associated with significant depressive symptoms (p = 0.005). Compared to no posterior cerebral artery (PCA) stenosis, having left PCA stenosis was associated with significant depressive symptoms (p = 0.022). In the multivariable linear regression analysis, only bilateral MCA stenosis had a positive association with the score of GDS-15 (p = 0.013). CONCLUSION: Bilateral MCA stenosis and left PCA stenosis are associated with significant depressive symptoms among elderly patients, with bilateral MCA stenosis positively associated with the severity of depression.

A unique anatomic variant: Left anterior choroidal artery arising proximal to fetal posterior communicating artery.

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.

[Posterior Communicating Artery / Posterior Cerebral Artery].

Thorough understanding of the vascular anatomy, including embryological development of vessels is important to safely perform endovascular procedures. The posterior cerebral and anterior choroidal arteries are embryologically complementary, which suggests a potential network. Numerous perforators originate from the posterior communicating and posterior cerebral arteries. The tuberothalamic artery arising from the posterior communicating artery and the thalamoperforating artery, which originates from the P1 segment of the posterior cerebral artery are clinically important because occlusion of these vessels can precipitate severe infarction. It is clinically important to be aware that the branching pattern of perforators differs based on the fusion type of the basilar tip. The balloon occlusion and Allcock test are useful to predict ischemic tolerance in cases of intentional artery occlusion. However, accurate prediction remains challenging, and a definitive evaluation method is unavailable. Flow disturbances in the cortical territory and local perforator impairment require close attention in cases of intentional artery occlusion.

The Potential Role of Preoperative Posterior Cerebral Artery Involvement in Predicting Postoperative Transient Neurological Deficits and Ischemic Stroke After Indirect Revascularization in Patients With Moyamoya Disease.

OBJECTIVE: Transient neurological deficits (TNDs) are known to develop after direct bypass for Moyamoya disease and may be risk factors for subsequent stroke. However, the factors involved in the development of TNDs and stroke after indirect revascularization alone, including their association with subsequent stroke, remain unclear. The purpose of this study was to investigate this issue. METHODS: The subjects of the study were 30 patients with Moyamoya disease who underwent a total of 40 indirect revascularization procedures at our institution. Clinical and radiological data were collected retrospectively. To examine factors associated with the development of postoperative TND/stroke/asymptomatic disease, the clinical characteristics of each group were statistically compared. RESULTS: The mean age at surgery was 7 years (range 1-63). TNDs developed after surgery in 9 out of 40 patients (22.5%). Stroke in the acute postoperative period occurred in 3 patients (7.5%), all of whom experienced cerebral infarctions. Demographic data and preoperative clinical information were not different between the groups. However, posterior cerebral artery involvement on preoperative imaging was significantly associated with the development of TNDs and stroke (P = 0.006). Furthermore, postoperative stroke was associated with unfavorable outcomes (P = 0.025). CONCLUSIONS: Posterior cerebral artery involvement is significantly associated with the occurrence of TNDs. In contrast, TNDs after indirect revascularization have little relationship with the subsequent development of stroke. TNDs usually resolve without new strokes, and a better understanding of this particular pathology could help establish an optimal treatment regimen.

Posterior Cerebral Artery-to-Superior Cerebellar Artery Side-to-Side Bypass via Extreme Lateral Supracerebellar Infratentorial Approach: Technical Note.

BACKGROUND: Difficult-to-treat aneurysms of the distal posterior cerebral artery (PCA) can often be treated by parent artery occlusion. A cerebrovascular bypass can complement PCA occlusion to curb the risk of ischemic complications. An in situ bypass may be considered when the occipital artery or superficial temporal artery cannot serve as a bypass donor. This article describes the use of a side-to-side bypass of superior cerebellar artery as a donor to the PCA via an extreme lateral supracerebellar infratentorial approach (ELSCIT). This bypass approach can be a useful surgical strategy for PCA revascularization. METHODS: A 40-year-old woman underwent a side-to-side PCA-superior cerebellar artery bypass via the ELSCIT approach for to treat a complex and previously coiled PCA aneurysm. The bypass was followed by endovascular aneurysm and parent artery occlusion. RESULTS: Postoperatively, the patient experienced transient, partial trochlear nerve palsy of the left eye without ischemic lesions on magnetic resonance imaging. The clinical condition was stable, and angiography showed a patent bypass and complete aneurysm occlusion 12 months after surgery. CONCLUSIONS: The ELSCIT approach offers access to the medial and distal PCA that is suitable for a side-to-side PCA-superior cerebellar artery bypass. This type of approach and bypass may be of value when revascularization of a P2-P3 portion of the PCA is needed, but a suitable occipital artery or superficial temporal artery is not available.

Neurovascular Coupling in Acutely Concussed Adolescent Patients.

Neurovascular coupling (NVC) uniquely describes cerebrovascular response to neural activation and has demonstrated impairments following concussion in adult patients. It is currently unclear how adolescent patients experience impaired NVC acutely following concussion during this dynamic phase of physiological development. The purpose of this study was to investigate NVC in acutely concussed adolescent patients relative to controls. We recruited patients presenting to a sports medicine practice within 28 days of a concussion or a musculoskeletal injury (controls). Transcranial Doppler ultrasound was used to measure changes in patients' posterior cerebral artery (PCA) velocity in response to two progressively challenging visual tasks: (1) reading and (2) visual search. Each task was presented in five 1-min trials (20 sec eyes closed/40 sec eyes open). Resting PCA velocity data were derived by averaging PCA velocity across a 2-min baseline period that preceded the visual tasks. Filtered task data were converted to time-series curves representing 40 consecutive 1-sec averages for each trial. Curves were then averaged across the five trials and time-aligned to stimulus onset (eyes open) to generate a single ensemble-averaged 40-sec curve representing NVC response for each participant for each task. Independent t tests were used to assess group differences (concussion vs. control) in resting PCA velocity. Separate linear mixed-effects models were used to evaluate group differences (concussion vs. control) in NVC response profiles for both visual tasks and group-by-task interaction. Twenty-one concussion patients (female = 8 [38.1%]; age = 14.4 ± 1.9 years) and 20 controls (female = 7 [35.0%]; age = 14.4 ± 1.9 years) were included in our analysis. Average resting PCA velocity did not significantly differ between concussion patients (36.6 ± 8.0 cm/sec) and controls (39.3 ± 8.5 cm/sec) (t39 = 1.06; p = 0.30). There were no significant group differences in relative NVC response curves during the reading task (F1,1560 = 2.23; p = 0.14) or the visual search task (F1,1521 = 2.04; p = 0.15). In contrast, the differential response to task (e.g., increase from reading task to visual search task) was significantly greater in concussion patients than in controls (p < 0.0001). The NVC response to the visual search task was 7.1% higher than the response to reading in concussion patients relative to being 5.5% higher in controls. Our data indicate that concussed patients present with a significantly greater response to more difficult tasks than do controls, suggesting that concussed adolescents require increased neural resource allocation as task difficulty increases. The study provides insight into the neurophysiological consequences of concussion in adolescent patients.

Aneurysms Located beyond the Origin of the Major Branches in the Posterior Circulation.

AIM: To evaluate the clinical and radiological features, treatment modalities, and outcomes of unusual aneurysms located beyond the origin of the major branches in the posterior circulation, and to introduce changes in the recent treatment trends due to rapid innovations in endovascular technology. MATERIAL AND METHODS: This was a retrospective study of patients who underwent treatment for these unusual aneurysms, including those that were identified in regular follow-up after treatment, between March 2009 and April 2023. Medical information including the radiological features of the aneurysms, incidences of rebleeding, associated vascular diseases, treatment modalities, and outcomes, was documented. RESULTS: A total of 22 cases consisting of two unruptured and 20 ruptured aneurysms were included. Their locations were the posterior cerebral artery in four cases, the superior cerebellar artery in three, the anterior inferior cerebellar artery in two, and the posterior inferior cerebellar artery in 13. Sixteen were saccular, five fusiform, and one blister-like. Eight were pseudo-aneurysms and pre- or intra-operative rebleeding occurred in 13 (65%) of 20 cases with ruptured aneurysms. Five aneurysms coexisted with causative vascular diseases such as arteriovenous malformation, moyamoya disease, or dolichoectasia. Four cases were treated by microsurgical operations and 18 by endovascular operations. In one of the microsurgical cases and five of the endovascular cases, parent arteries were sacrificed. Stents were used in six cases, including low-profile stents in four. Intermediate guiding catheters were used in seven cases for distal access. Full recoveries were seen in 17 cases and death occurred in three. CONCLUSION: Treatments for these aneurysms are technically demanding due to the high rate of rebleeding, difficult accessibility, and inevitable necessity of sacrifice of the parent artery in some cases. However, advancing endovascular techniques and devices enable distal access to the lesion and help preserve the parent artery.

Posterior cerebral artery (PCA)-accessory PCA (hyperplastic anterior choroidal artery) anastomosis detected on magnetic resonance angiography.

PURPOSE: To describe a case of posterior cerebral artery (PCA)-accessory PCA (hyperplastic anterior choroidal artery) anastomosis detected on magnetic resonance angiography. METHODS: A 76-year-old man with a history of cerebral infarction underwent cranial magnetic resonance (MR) imaging and MR angiography of the intracranial region for the evaluation of brain and vascular lesions. The MR machine was a 3-Tesla scanner. MR angiography was performed using a standard three-dimensional time-of-flight technique. RESULTS: There were two right PCAs. The parieto-occipital and calcarine arteries of the right PCA arose from the right ICA, indicative of accessory PCA, and there were three stenotic lesions at the proximal segment of this artery. The temporal artery of the right PCA originated from the basilar artery. A small anastomotic channel between these two arteries was identified on partial maximum intensity projection (MIP) images. Computed tomography angiography was additionally performed and the findings were confirmed. CONCLUSION: We speculated that the pressure gradient between the PCA and the accessory PCA enlarged the anastomotic channel. Partial MIP images are useful for diagnosing small arterial variations using MR angiography.

Successful Thrombectomy of the Posterior Cerebral Artery P2 Segment in a 61-Year-Old Man with Acute Ischaemic Stroke: A Case Report.

BACKGROUND Acute ischemic stroke in the posterior cerebral artery (PCA) territory can lead to persistent disabling deficits. The PCA is divided into 4 segments. The P2 segment begins at the posterior communicating artery and curves around the midbrain and above the tentorium cerebelli. This report is of a 61-year-old man with acute ischemic stroke involving the left hippocampus treated with direct thrombectomy of the P2 segment of the PCA. CASE REPORT A 61-year-old white man presented with transient amnesia, aphasia, right-sided hemianopia, dizziness, and persistent acute memory deficits. Magnetic resonance imaging (MRI) showed a left hippocampal acute ischemic stroke with left PCA occlusion in the P2 segment. Despite a low National Institutes of Health Stroke Scale (NIHSS) score and the already-formed lesion in the hippocampus, successful stent retriever thrombectomy was performed due to a considerable perfusion-diffusion mismatch and a persistent potentially disabling neurocognitive deficit. Due to partial thrombus dislocation, occlusion of the common origin of the right posterior inferior cerebellar artery (PICA) and anterior inferior cerebellar artery (AICA) occurred and was immediately treated by thrombectomy to prevent severe cerebellar infarction. His clinical symptoms completely resolved and a neuropsychological exam showed no residual deficits. CONCLUSIONS Thrombectomy of the P2 segment of the PCA is feasible and can be considered to treat patients with acute occlusion at risk for persistent disabling deficits, based on clinical estimation of the impact of such deficits and the presence of potentially salvageable brain tissue. Potential procedural complications should be sought out and immediately treated, if technically feasible.

[Features of aphasic disorders in patients with acute cerebrovascular disorder in the posterior cerebral artery basin]. / Osobennosti afaticheskikh rasstroistv u patsientov s ostrym narusheniem mozgovogo krovoobrashcheniya v basseine zadnei mozgovoi arterii.

Aphasia is a systemic disorder of formed speech that develops as a result of local brain lesions. Most aphasias are characterized by damage to secondary cortical fields, which in turn are responsible for the performance of the functions of gnosis and praxis, which explains the variability in the manifestations of speech disorders in patients with acute cerebrovascular accidents. However, it is necessary in each case to diagnose the central pathological mechanism, which underlies the development of the entire syndrome and determines the entire clinical picture. The most important task of a speech therapist-aphasiologist is to qualify the defect, namely to isolate the mechanism and analyze the syndrome in order to select individual methods of corrective restoration. This article presents a case of a patient with an ischemic stroke in the left posterior cerebral artery with the development of amnestic aphasia in combination with alexia without agraphia.

Comparable dynamic cerebral autoregulation and neurovascular coupling of the posterior cerebral artery between healthy men and women.

AIMS: Most studies focus on dynamic cerebral autoregulation (dCA) in the middle cerebral artery (MCA), and few studies investigated neurovascular coupling (NVC) and dCA in the posterior cerebral artery (PCA). We investigated NVC and dCA of the PCA in healthy volunteers to identify sex differences. METHODS: Thirty men and 30 age-matched women completed dCA and NCV assessments. The cerebral blood flow velocity (CBFV) and mean arterial pressure were evaluated using transcranial Doppler ultrasound and a servo-controlled plethysmograph, respectively. The dCA parameters were analyzed using transfer function analysis. The NCV was evaluated by eyes-open and eyes-closed (24 s each) periodically based on voice prompts. The eyes-open visual stimulation comprised silent reading of Beijing-related tourist information. RESULTS: The PCA gain was lower than that of the MCA in all frequency ranges (all p < 0.05). Phase was consistent across the cerebrovascular territories. The cerebrovascular conductance index (CVCi) and mean CBFV (MV) of the PCA were significantly higher during the eyes-open than eyes-closed period (CVCi: 0.50 ± 0.12 vs. 0.38 ± 0.10; MV: 42.89 ± 8.49 vs. 32.98 ± 7.25, both p < 0.001). The PCA dCA and NVC were similar between the sexes. CONCLUSION: We assessed two major mechanisms that maintain cerebral hemodynamic stability in healthy men and women. The visual stimulation-evoked CBFV of the PCA was significantly increased compared to that during rest, confirming the activation of NVC. Men and women have similar functions in PCA dCA and NCV.

Differences in intracranial atherosclerosis plaque between posterior circulation and anterior circulation on high-resolution magnetic resonance imaging: A systematic review and meta-analysis.

OBJECTIVE: The clinical characteristics and mechanisms of stroke caused by anterior circulation atherosclerotic plaques (ACAPs) and posterior circulation atherosclerotic plaques (PCAPs) are distinct. We aimed to compare the differences in vulnerability, morphology, and distribution between ACAPs and PCAPs based on hign-resolution magnetic resonance imaging (HR-MRI). MATERIALS AND METHODS: The PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang database were retrieved from inception through May 2023. Meta-analysis was performed by R 4.2.1 software. The quality of the literature was assessed by the Agency for Healthcare Research and Quality (AHRQ). Subgroup analysis was conducted to explore the heterogeneity of the pooled results. RESULTS: There were a total of 13 articles, including 1194 ACAPs and 1037 PCAPs. The pooled estimates demonstrated that the incidence of intraplaque hemorrhage in the PCAPs was higher (OR 1.72, 95%CI 1.35-2.18). The plaque length (SMD 0.23, 95%CI 0.06-0.39) and remodeling index (SMD 0.29, 95%CI 0.14-0.44) of PCAPs were larger than those in ACAPs. However, there were no evident differences in significant enhancement or stenosis degree between the two groups. CONCLUSION: There were more unstable features in PCAPs, highlighting an elevated risk of recurrent ischemic stroke in the posterior circulation. Furthermore, PCAPs were prone to developing penetrating artery disease due to their wider distribution. Nevertheless, posterior circulation arteries exhibited a greater propensity for outward remodeling, which may lead treatment team to miss the optimal intervention stage by being overlooked on angiographic detection.

Replaced posterior cerebral artery.

PURPOSE: Replaced posterior cerebral artery (PCA), defined as a hyperplastic anterior choroidal artery (AChA) supplying all branches of the PCA, is an extremely rare anatomical variation. To the best of our knowledge, there are only a few reports of replaced PCA. METHODS: Herein, we report a case of replaced PCA diagnosed by digital subtraction angiography. RESULTS: A 76-year-old woman visited a neurosurgical clinic because of headache and vertigo. Magnetic resonance imaging and magnetic resonance angiography incidentally revealed a left internal carotid artery aneurysm. She was referred to our hospital for further examination and treatment of the unruptured intracranial aneurysm. Left internal carotid angiography revealed a paraclinoid aneurysm. We also incidentally found an anomalous hyperplastic AChA distal to the aneurysm. This hyperplastic AChA supplied not only the AChA territory but also the entire PCA territory. No vessels that could be a normal AChA or posterior communicating artery were identified along the left internal carotid artery. Vertebral angiography demonstrated that the left PCA was not visualized. With these findings, we diagnosed anomalous hyperplastic AChoA in this case as replaced PCA. CONCLUSION: Careful imaging assessment is important to identify replaced PCA. Both direct findings of a hyperplastic AChA course and perfusion territory and indirect findings of the absence of the original PCA are useful in the diagnosis of replaced PCA.

Accessory posterior cerebral artery (hyperplastic anterior choroidal artery) associated with contralateral accessory middle cerebral artery incidentally diagnosed by magnetic resonance angiography.

PURPOSE: To describe a case of accessory posterior cerebral artery (PCA) [hyperplastic anterior choroidal artery (AChA)] associated with contralateral accessory middle cerebral artery (MCA) incidentally diagnosed by magnetic resonance (MR) angiography. METHODS: A 71-year-old man with paroxysmal atrial fibrillation underwent cranial MR imaging and MR angiography of the intracranial region using a 1.5-T scanner for the evaluation of brain and vascular lesions. RESULTS: On MR angiography, two right PCAs of equal size arose from the internal carotid artery instead of the basilar artery. Additionally, a small left MCA branch arose from the proximal A2 segment of the anterior cerebral artery (ACA). CONCLUSION: One of the branches of the PCA rarely arises from the AChA. This variation is referred to as a hyperplastic AChA or accessory PCA. The latter name was recently proposed and may be more appropriate than the former name. An MCA branch arising from the ACA is called an accessory MCA. It is a frontal branch of two types: proximal-origin and distal-origin. The distal-origin accessory MCA arises from the distal A1 segment, A1-A2 junction or proximal A2 segment. Distal-origin accessory MCAs are rare. Our patient had two rare variations: an accessory right PCA and a distal-origin accessory left MCA. To identify cerebral arterial variations, especially accessory MCA, volume-rendering images are more useful than maximum-intensity projection images on MR angiography.

Endovascular Treatment in Precommunicating Segment Aneurysms of Posterior Cerebral Artery.

BACKGROUND: Precommunicating (P1) segment aneurysms of the posterior cerebral artery are rare, with few studies reported to date. Herein, we address the clinical and radiologic outcomes of their endovascular treatment. METHODS: For this study, we retrieved prospectively collected data on 35 consecutive patients with 37 P1 aneurysms, analyzing the clinical ramifications and morphologic outcomes of treatment. All subjects received endovascular interventions between January 2001 and October 2021. RESULTS: There were 16 aneurysms (43.2%) of P1 segment sidewalls and 21 (56.8%) at P1/posterior communicating artery junctions. Five (13.5%) were fusiform, and 14 (37.8%) were ruptured. In 14 patients (40%), 16 aneurysms (43%) were associated with intracranial arterial occlusive disease of the anterior circulation. Selective coiling was undertaken in 34 aneurysms (91.9%), using single (n = 24) or double (n = 4) microcatheters, microcatheter protection (n = 2), or stents (n = 4); and trapping was done in 3 (8.1%). No procedure-related morbidity or mortality resulted. Excluding the trapped lesions, angiographic follow-up of 29 aneurysms obtained >6 months after embolization (mean, 12.4 month) revealed stable occlusion in 21 (72.4%), with some recanalization in the other 8 (minor: 3/29, 10.4%; major: 5/29, 17.2%). CONCLUSIONS: Aneurysms of P1 segment (vs. other locations) are strongly associated with intracranial arterial occlusive disease of the anterior circulation and thus are likely flow related. Endovascular treatment of such lesions seems safe and efficacious, despite the array of technical strategies that their distinctive anatomic configurations impose.