Characterization of posterior circulation blood perfusion in patients with different degrees of basilar artery tortuosity.

OBJECTIVE: The morphology of basilar artery (BA) may affect posterior circulation blood perfusion. We aimed to investigate whether different degrees of BA tortuosity could lead to the alterations of posterior circulation perfusion. METHODS: We collected 138 subjects with different BA tortuosity scores, including 32 cases of score 0, 45 cases of score 1, 43 cases of score 2, and 18 cases of score 3. A higher score represented a higher degree of BA tortuosity. Ordered logistic regression analysis was performed to investigate the risk factors for BA tortuosity. We quantitatively measured the cerebral blood flow (CBF) in eight posterior circulation brain regions using arterial spin labeling. SPSS 25.0 was used for statistical analysis. The correlation between the CBF and BA tortuosity was corrected by the Bonferroni method. The significance level was set at 0.006 (0.05/8). RESULTS: Hypertension (HR: 2.39; 95%CI: 1.23-4.71; P = 0.01) and vertebral artery dominance (HR: 2.38; 95%CI: 1.10-4.67; P = 0.03) were risk factors for BA tortuosity. CBF in occipital gray matter (R = -0.383, P < 0.001), occipital white matter (R = -0.377, P < 0.001), temporal gray matter (R = -0.292, P = 0.001), temporal white matter (R = -0.297, P < 0.001), and cerebellum (R = -0.328, P < 0.001) were negatively correlated with BA tortuosity degree. No significant correlation was found between the BA tortuosity degree and CBF in hippocampus (R = -0.208, P = 0.014), thalamus (R = -0.001, P = 0.988) and brainstem (R = -0.204, P = 0.016). CONCLUSIONS: BA tortuosity could affect posterior circulation blood perfusion. CBF was negatively correlated with BA tortuosity degree. The morphology of BA may serve as a biomarker for posterior circulation and the severity of posterior circulation ischemia.

[Basilar Artery, Anterior Inferior Cerebellar Artery, Superior Cerebellar Artery].

The basilar artery(BA)is formed by the fusion of two longitudinal arteries, and incomplete development may lead to BA fenestration. The BA provides many short perforating arteries and long lateral pontine arteries to the brain stem. The anterior inferior cerebellar artery(AICA)usually branches from the proximal third of the BA and primarily perfuses the ventral, inferior and lateral aspect of the cerebellum and inner ear organ. However, there are many variations to the AICA that depend on the degree of posterior inferior cerebellar artery development. The superior cerebellar artery(SCA)branches into not only to the rostral, ventral aspect of the cerebellar hemisphere, but also to the deeper cerebellar nucleus and brain stem. Duplications within this vessel are frequently identified, but it is not missing.

An anatomical study of persistent trigeminal artery detected by computed tomography angiography and magnetic resonance angiography: proposal for a modified classification and a novel basilar artery grading system.

PURPOSE: The purpose of this study is to investigate the anatomical characteristics of persistent trigeminal artery (PTA) detected by computed tomography angiography (CTA) and magnetic resonance angiography (MRA), propose a modified classification and a novel grading system for basilar artery (BA). METHODS: Patients who underwent head CTA or MRA in our hospital between August 2014 and August 2022 were reviewed retrospectively. The prevalence, sex, and course of PTA were evaluated. PTA types were modified based on Weon's classification. Type I to IV were similar to those in Weon's classification except the presence of intermed fetal-type posterior cerebral artery (IF-PCA). Type V was the same as that in Weon's classification. Type VI included subtypes of VIa (concomitant IF-PCA based on type I to IV) and VIb (other variants). BA was assessed based on a scale of 0 to 5 compared with PTA's caliber (0, BA aplasia; 1 and 2, BA non-dominant; 3, equilibrium; 4 and 5, BA dominant). RESULTS: A total of 57 patients (0.06%) with PTA, including 36 females and 21 males, were detected in 94,487 patients. Six patients (10.5%) were medial type and 51 patients (89.5%) were lateral type. Thirty-seven patients (64.9%) were type I, 1 (1.8%) as type II, 13 (22.8%) as type III, 3 (5.3%) as type IV, 1 (1.8%) as type V, and 2 (3.5%) as type VI. For BA grading, 4 (7.0%), 21 (36.8%), 17 (29.8%), 6 (10.5%), 6 (10.5%), and 3 (5.3%) of the patients were grade 0, 1, 2, 3, 4, and 5, respectively. Fifteen patients (26.3%) had intracranial aneurysms. One cases (1.8%) had a fenestration of the PTA. CONCLUSION: The prevalence of PTA in our study was lower than that in most previous reports. The modified PTA classification and BA grading system can be used to better understand the vascular structure of PTA patients.

Persistent trigeminal artery variant associated with ipsilateral hypoplasia of the internal carotid artery.

A persistent trigeminal artery is the most common persistent carotid-vertebrobasilar anastomosis, while persistent trigeminal artery variants involve termination at the cerebellar artery without connecting to the basilar artery. Internal carotid artery hyperplasia is also a rare congenital anomaly. To the best of our knowledge, there are no reports of persistent trigeminal artery variant associated with ipsilateral hypoplasia of the internal carotid artery. Herein, we report a case of a 44 year-old woman who visited a neurosurgical clinic because of chronic headaches. Magnetic resonance angiography showed impaired delineation of the left internal carotid artery, and she was referred to our hospital for catheter angiography. Angiogram revealed left internal carotid artery hypoplasia and a left persistent trigeminal artery variant that terminated at the left anterior inferior cerebellar artery. Computed tomography bone images showed a narrow left carotid canal. We diagnosed congenital hypoplasia of the left internal carotid artery concomitant with ipsilateral persistent trigeminal artery variant. Careful imaging assessment is important for identifying persistent trigeminal artery variant when associated with ipsilateral internal carotid artery hypoplasia.

Duplicated posterior inferior cerebellar arteries one of which was supplied by the jugular branch of the ascending pharyngeal artery.

PURPOSE: To describe a case of duplicated posterior inferior cerebellar arteries (PICAs), one of which was supplied by the jugular branch of the ascending pharyngeal artery (APA). CASE REPORT: A 62-year-old man with cerebral infarction underwent cranial magnetic resonance (MR) imaging and MR angiography. MR angiography showed a hyperplastic left APA, that was found to enter the posterior cranial fossa and continue to the PICA. Another left PICA arising from the V4 segment of the left vertebral artery (VA) and a tiny left anterior inferior cerebellar artery (AICA) were also identified. The source images of MR angiography revealed that the anomalous artery was passing through the medial side of the jugular foramen pars vascularis. The two left PICAs did not fuse to each other. DISCUSSION: There are four types of the PICA arising from the carotid system: (1) the PICA arises from the cavernous segment of the internal carotid artery (ICA) (persistent trigeminal artery variant); (2) the PICA arises from the cervical segment of the ICA (persistent hypoglossal artery variant); (3) the PICA arises from the APA via the hypoglossal canal; and (4) the PICA arises from the APA via the jugular foramen. Two PICAs sometimes arise from the V4 segment of the VA. In this common variation, the AICA is usually absent. This is the first reported case involving the association of (4) and a duplicated PICA with a tiny AICA. CONCLUSION: To identify this variation, careful observation of source images and creation of partial maximum-intensity-projection images of MR angiography are important.

Persistent trigeminal artery associated with an occipital arteriovenous malformation: a case report and literature review.

BACKGROUND: Persistent trigeminal artery or persistent primitive trigeminal artery (PTA) is the most common carotid-basilar anastomosis in both cadaveric and live patient studies, followed by persistent hypoglossal and persistent otic arteries. Approximately 0.2% of all angiographies reported this finding. CASE REPORT: We present the case of a 21-year-old male who arrived at the emergency department with tonic‒clonic seizures. After performing diagnostic contrast magnetic resonance imaging and digital subtraction angiography, the patient was diagnosed with a right occipital arteriovenous malformations (AVM) fed by the right calcarine artery associated with an ipsilateral PTA. After considering surgical and endovascular treatment options, the patient was selected for watchful waiting. We included a literature review of the PTA, the results of a PubMed search regarding the combined presence of these findings, and a brief discussion providing insight into the implications for treatment. CONCLUSIONS: Although several studies have linked PTA to different vascular pathologies, such as cerebral aneurysms, the association between PTA and AVMs remains scarce. This case, along with the literature review, shows that further research is needed to characterize the relationship between these findings.

MN1 C-terminal truncation syndrome is a novel neurodevelopmental and craniofacial disorder with partial rhombencephalosynapsis.

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3' region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.

Asymmetry of P1 and vertebral arteries is not related to basilar tip aneurysm development or rupture.

OBJECTIVE: Lately, morphological parameters of the surrounding vasculature aside from aneurysm size, specific for the aneurysm location, e.g., posterior cerebral artery angle for basilar artery tip aneurysms, could be identified to correlate with the risk of rupture. We examined further image-based morphological parameters of the aneurysm surrounding vasculature that could correlate with the growth or the risk of rupture of basilar artery tip aneurysms. METHODS: Data from 83 patients with basilar tip aneurysms (27 not ruptured; 56 ruptured) and 100 control patients were assessed (50 without aneurysms and 50 with aneurysms of the anterior circle of Willis). Anatomical parameters of the aneurysms were assessed and analyzed, as well as of the surrounding vasculature, namely the asymmetry of P1 and the vertebral arteries. RESULTS: Patients with basilar tip aneurysm showed no significant increase in P1 or vertebral artery asymmetry compared with the control patients or patients with aneurysms of the anterior circulation, neither was there a significant difference in asymmetry between cases with ruptured and unruptured aneurysms. Furthermore, we observed no significant correlations between P1 asymmetry and the aneurysm size or number of lobuli in the aneurysms. CONCLUSION: We observed no significant difference in aneurysm size, rupture, or lobulation associated with P1 or vertebral artery (surrounding vasculature) asymmetry. Therefore, the asymmetry of the surrounding vessels does not seem to be a promising morphological parameter for the evaluation of probability of rupture and growth in basilar tip aneurysms in future studies.

Persistent Primitive Hypoglossal Artery with Ipsilateral Symptomatic Carotid Artery Stenosis and Cerebral Aneurysm.

OBJECTIVE: Persistent primitive hypoglossal artery (PPHA) is a rare type of persistent carotid-basilar anastomosis sometimes associated with other vascular lesions. We treated an extremely rare case of PPHA with concomitant ipsilateral symptomatic cervical internal carotid artery (ICA) stenosis and unruptured aneurysm. CASE PRESENTATION: A 67-year-old woman visited our institution with acute onset of diplopia. Magnetic resonance imaging revealed multiple acute infarctions in the right anterior and posterior circulations. Digital subtraction angiography demonstrated the right PPHA concomitant with ipsilateral cervical ICA stenosis and an unruptured ICA aneurysm with maximum diameter of 8 mm. The multiple infarctions were considered to result from artery-to-artery embolism due to microthrombi from the ICA plaque passed along the PPHA, so carotid endarterectomy was performed as the first step with preoperative modified Rankin Scale (mRS) grade 1. During the operation, the patient had impaired ICA perfusion due to internal shunt catheter migration into the PPHA followed by acute infarction in the right hemisphere causing mild left hemiparesis. The patient was transferred to the rehabilitation hospital with mRS grade 3. After 3 months of rehabilitation, the patient recovered to mRS grade 1 and clipping surgery for the unruptured right ICA aneurysm was performed as the second step with uneventful postoperative course. CONCLUSION: The treatment strategy should be carefully considered depending on the specific blood circulation for such cases of PPHA with unique vasculature.

A unique finding of the basilar artery.

Variants of the posterior intracranial circulation are important for surgeon, interventionalists and radiologists. Herein, a unique configuration of the basilar artery is reported. A 54-year-old man with a history of COPD, hypothyroidism, smoking, and hyperlipidemia presented to an outside institution with nausea, confusion, altered mental status, and ataxia. The patient was evaluated for stroke. Imaging revealed rotation of the basilar apex of 180 degrees, fetal configuration of the posterior communicating artery, right posterior cerebral artery filling from the left vertebral artery, and duplication of the left and right superior cerebellar arteries. The patient continued to deteriorate neurologically and MRI revealed multifocal and symmetric signal abnormalities in the brain stem, thalami, basal ganglia, and hippocampi. The differential diagnosis included acute disseminated myeloencephalitis. Despite plasma exchange and steroid therapy, the patient died a few days later. This case report demonstrates a rare variation of the basilar apex.

Medial type persistent trigeminal artery associated with a saccular aneurysm at its trunk.

There are four types of fetal anastomosis between the carotid and vertebrobasilar arteries at 5 weeks gestation; from caudal to cranial position, these involve the proatlantal intersegmental, hypoglossal, otic, and trigeminal arteries. Excluding otic artery, these arteries may persist rarely. Persistent trigeminal artery (PTA) is the most common carotid-vertebrobasilar anastomosis, and the medial type (intrasellar) PTA is quite rare, accounting for approximately 10% of all PTA cases. An aneurysm is occasionally found at the origin of the PTA. Rarely, an aneurysm arises at the trunk of the PTA. Using magnetic resonance angiography, we identified a case of medial type PTA with an unruptured saccular aneurysm at its trunk.

Anatomical Variations of Vertebrobasilar Artery are Closely Related to the Occurrence of Vertebral Artery Dissection-An MR Angiography Study.

GOAL: Intracranial arterial dissection is a major cause of ischemic stroke and subarachnoid hemorrhage in relatively young patients. We assessed the hypothesis that the tortuosity of the vertebrobasilar artery is associated with the occurrence of vertebral artery (VA) dissection, using MR angiography (MRA). MATERIALS AND METHODS: This study enrolled 43 patients with VA dissection, and 63 age- and sex-matched healthy subjects were used as the controls. MRA was employed to evaluate the presence of dominant VA and the lateral shift of vertebrobasilar junction in both groups. The VA diameters were considered different when the difference was greater than .3 mm. These anatomical variations were divided into 3 types: Type 1 (vertebrobasilar junction within 2 mm from the midline), Type 2 (>2 mm-lateral shift of vertebrobasilar junction to the ipsilateral side of the dominant VA), and Type 3 (>2 mm-lateral shift of vertebrobasilar junction to the contralateral side of the dominant VA). FINDINGS: The presence of dominant VA and the lateral shift of vertebrobasilar junction were more prevalent in patients with VA dissection than in the controls (OR: 3.46, P = .013, and OR: 4.51, P = .001, respectively). The lateral shift of vertebrobasilar junction was classified into Type 1 (n = 6), Type 2 (n = 13), and Type 3 (n = 17) among patients with VA dissection, while into Type 1 (n = 20), Type 2 (n = 8), and Type 3 (n = 7) among the controls. Type 3 predominance was observed in patients with VA dissection (P = .02). CONCLUSIONS: Anatomical variations of the vertebrobasilar artery may play an important role in the occurrence of VA dissection.

Low origin of the persistent hypoglossal artery associated with high carotid bifurcation: a case report.

PURPOSE: Persistent hypoglossal artery (PHA) is the second most common anastomosis between the carotid and vertebrobasilar systems and it demonstrates some variations. METHODS: Using magnetic resonance angiography, we diagnosed a case of low origin of the PHA associated with the high carotid bifurcation, and the resulting origin close to the carotid bifurcation. RESULTS: The PHA is typically clinically silent as in our case, but it could be a potential cause of glossopharyngeal neuralgia, hypoglossal palsy, and intracranial aneurysms or technical complications in interventional procedure such as carotid stenting. CONCLUSIONS: We have described a case of low origin of the PHA associated with high carotid bifurcation. To the best of our knowledge, no similar case has been reported in the English-language literature.

Acute Cerebral Infarction in a Patient with Persistent Trigeminal Artery and Homolateral Hypoplasia of Internal Carotid Artery Distal Anastomosis: A Case Report and a Mini Review of the Literature.

BACKGROUND: Persistent primitive trigeminal artery (PPTA) is a rare remnant between the internal carotid artery (ICA) and the basilar artery into adulthood. PPTA generally lacks specific clinical manifestations and occasionally accompanies with other cerebrovascular diseases. CASE PRESENTATION: We reported a 48-year-old Chinese woman who had repeated episodes of transient ischemic attack presented to our hospital. She had no related risk factors of ischemic cerebrovascular diseases. Magnetic resonance image findings demonstrated acute cerebral infraction in centrum semiovale. Magnetic resonance angiography findings indicated right PPTA and ipsilateral hypoplasia of ICA distal anastomosis. CONCLUSIONS: To the best of our knowledge, this is the first report that acute cerebral infarction in a patient with the right PPTA and ipsilateral hypoplasia of ICA distal anastomosis. According to the literature, congenital factor may play an important role in the formation of these vascular anomalies.

Carotid-Cavernous Sinus Fistula caused by Persistent Primitive Trigeminal Artery Aneurysm rupture: A case report.

Carotid-Cavernous sinus fistula (CCF) caused by a ruptured aneurysm of persistent primitive trigeminal artery (PPTA) is exceptionally rare. Herein, we reported the case of a 64-year-old female who presented with headache, pulsatile tinnitus, and diplopia. Angiography showed a PPTA and CCF. Three-dimensional digital subtraction angiograms revealed a direct shunt between the PPTA aneurysm and the left cavernous sinus. The trigeminal carotid fistula was successfully treated with detachable coils and Onyx, and the PPTA was preserved. Hence, coil and Onyx occlusion of the cavernous sinus is a safe and effective treatment for trigeminal carotid fistula.

Bilateral persistent hypoglossal arteries: a case report and literature review.

Bilateral persistent hypoglossal arteries (PHAs) are extremely rare, with only 5 cases reported in the English-language literature. Using magnetic resonance angiography, we diagnosed a case in which the left side was a typical PHA and the right side was presumed a PHA variant that supplied only the posterior inferior cerebellar artery.

Recurrent cerebral infarction in anterior and posterior circulation territories associated with persistent primitive hypoglossal artery and carotid artery dissection: a case report.

The persistent primitive hypoglossal artery (PPHA) is the second most common persistent carotid-vertebrobasilar anastomosis. We present a rare case of an 82-year-old woman who diagnosed as acute cerebral infarction three times in both the anterior and posterior circulation territories with a right-sided PPHA and ipsilateral carotid artery dissection (CAD). Microembolus monitoring results suggested that microembolic caused by CAD associated with PPHA should be recognized as a possible cause of multiple infarctions in both the anterior and posterior circulation territories. For these patients, appropriate treatment measures should be taken for prevention of stroke recurrence.

Congenital absence of the internal carotid artery with a persistent primitive trigeminal artery as a collateral pathway: a report of an anatomic variation.

Congenital absence of the internal carotid artery (ICA) is rare, and patients with such a condition are often asymptomatic throughout their lifetime, because of sufficient collateral circulation. Collateral flow is provided via various channels; however, the role of persistent embryonic vessels under conditions in which the ICA is absent or occluded is unknown. We report a rare case of congenital absence of the left ICA and describe the collateral pathway consisting of a persistent trigeminal artery.

Variant of a persistent hypoglossal artery supplying only the posterior inferior cerebellar artery diagnosed by magnetic resonance angiography: a case report.

Very rarely, a persistent hypoglossal artery supplies only the posterior inferior cerebellar artery without connection to the basilar artery. Few cases diagnosed by catheter angiography have been reported. We diagnosed a case using magnetic resonance angiography.

Basilar artery hypoplasia associated with changes of brainstem potential, transcranial Doppler and perfusion-weighted imaging.

OBJECTIVE: The aim of this study was to observe brainstem hemodynamic alterations associated with basilar artery hypoplasia (BAH). METHODS: Nine hundred and fifty-two consecutive patients received emergency multimodal computed tomography; magnetic resonance imaging and magnetic resonance angiogram during the period of January 2011 to December 2014 were included. The vascular risk factors, brainstem auditory evoked potential (BAEP), blink reflex (BR), transcranial Doppler (TCD) and dynamic susceptibility contrast-enhanced perfusion-weighted imaging were completed. RESULTS: There was significant difference in the abnormal rates of TCD and BAEP between BAH and non-BAH patients. A positive correlation between basilar artery diameter and systolic velocity among BAH patients was suggested. V-wave value was used to predict posterior circulation infarction (PCI) with the sensitivity of 0.933 and specificity of 0.50 with the cutoff value of 5.97 s. Abnormal BR rate was also significantly different in BAH and non-BAH patients. The latency of R2 was used to predict PCI with the sensitivity of 0.933 and specificity of 0.50 with the cutoff value of 46.4 ms. The incidence of hypoperfusion was higher in BAH than non-BAH group and it was significant difference. CONCLUSION: BAH is closely associated with hemodynamic alterations within the pons, which might contribute to vascular vertigo due to regional hypoperfusion.