Persistent trigeminal artery: a cross-sectional study based on over 3 years conventional angiography, CT angiography and MR angiography images

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 Terminating in the Ipsilateral Superior Cerebellar Artery

Persistent trigeminal artery (PTA) represent an unusual remnant of the fetal carotid-basilar anastomosis. Persistent trigeminal artery variant (PTAV) is a rare anastomosis between the internal carotid artery and cerebellar artery, without an interposing basilar artery segment. We report the case of 49-year-old female with an incidentally discovered, rare variation of PTA that directly terminated in the ipsilateral superior cerebellar artery. The variation was observed on CT angiography, digital subtraction angiography, and MR angiography. Additionally, we reviewed the embryogenesis of PTA and PTAV and discussed the clinical implications of this variation.

The Relationship Between Posterior Communicating Artery Formation and Vertebral Artery Flow Parameters

Objectives:

It is important to know the range of normal vertebral artery (VA) flow volume. Diminished VA flow volume is associated with vertebrobasilar insufficiency. The study aim was to investigate the relationship between the posterior communicating artery (PCoA) calibration and the VA flow parameters, in patients with no underlying cerebrovascular disease, below 50 years of age.

Materials and Methods:

The study population consisted of 102 cases below 50 years of age. The basilar artery (BA), internal carotid artery (ICA), and the PCoA calibrations were measured with magnetic resonance angiography. The VA flow parameters (maximum systolic velocity, end-diastolic velocity, mean velocity, VA flow volume, and VA calibration) were measured with duplex sonography.

Results:

There was no statistically significant difference between these two imaging groups, in terms of VA Vmax, VA flow volumes, VA calibrations, and BA calibrations. However, the mean right ICA and mean left ICA calibrations were significantly higher in group 2 than group 1 ( P < .01). There was no significant correlation between mean PCoA calibration and mean Vmax, mean calibration, and the total flow volume of vertebral arteries.

Conclusion:

The findings indicate that the VA flow rate may be relatively maintained, regardless of PCoA measurements in this study.

A unique temporary collateral pathway between carotid-vertebrobasilar arteries in a carotid dissection patient

Background

In adults, the anastomosis between carotid and vertebrobasilar arteries is usually the posterior communicating artery, sometimes the primitive trigeminal artery. In this case, the basilar artery fed the internal carotid artery through the pontine-to-tentorial artery anastomosis after severe stenosis from traumatic carotid dissection.

Case presentation

A 32-year-old female was diagnosed with ischemic stroke caused by traumatic carotid artery dissection. Aspirin (100 mg/day) and clopidogrel (75 mg/day) were prescribed. Digital subtraction angiography performed 6 days after stroke onset showed a dissection in the cervical segment of left internal carotid artery with severe local stenosis, and a collateral pathway from BA to the cavernous segment of internal carotid artery through the lateral pontine and tentorial artery. Without interventional therapy, clinical symptoms improved significantly within 10 days after onset. At 3-month follow-up, left common carotid artery angiography showed the stenosis had been significantly improved with a residual aneurysm. There was no collateral pathway between carotid-vertebrobasilar arteries, and a residual small artery originated from the posterior vertical segment of cavernous internal carotid artery. The small artery was clearly visualized by 3-dimensional rotational angiography and identified the tentorial artery.

Conclusion

To the author’s knowledge, this is the first report of a collateral pathway between carotid vertebrobasilar arteries through the pontine-to-tentorial artery anastomosis. Meanwhile, tentorial artery origination directly from the cavernous segment of internal carotid artery is rare and easily mistaken for persistent primitive trigeminal artery. 3-dimensional rotational angiography can provide sensitive and accurate diagnostic assessment of the small artery, and may be a useful tool for screening of abnormal small arteries.

Prevalence and Clinical Implications of the Primitive Trigeminal Artery and its Variants: A Meta-Analysis

BACKGROUND

The primitive trigeminal artery (PTA) is the most common and the largest persistent carotid-basilar anastomosis. Primitive trigeminal artery variants (PTAVs) are anastomoses between the internal carotid artery and cerebellar arteries. These vessels pose a risk of hemorrhagic or ischemic complications during neurosurgical procedures in the parasellar and intrasellar regions. The aim of this study was to determine the prevalence of both PTA and PTAVs and their clinically important anatomic features.

METHODS

Major electronic databases were thoroughly searched for studies on PTA and PTAV. References in the included articles were also evaluated. Data regarding prevalence, laterality, origin, course patterns, and associated anomalies were extracted and pooled into a meta-analysis.

RESULTS

A total of 39 studies (110,866 patients) were included in the meta-analysis. The total pooled prevalence estimate of PTA and PTAVs combined was 0.4% (95% confidence interval [CI], 0.3-0.5). Individually, PTA was present in 0.3% of patients and PTAV in 0.2%. Both arteries most often originated from the C4 internal carotid artery and took a course lateral to the dorsum sellae. The anterior inferior cerebellar artery type was the predominant PTAV (72.1%). Basilar artery hypoplasia was found in 42.5% of patients with a PTA.

CONCLUSIONS

PTA and PTAVs are rare vessels, but they are clinically important because they can contribute to trigeminal neuralgia. Knowledge of the potential course of these arteries is essential in neuroradiology and neurosurgery, especially in minimally invasive procedures such as the endoscopic endonasal transsphenoidal approach to the pituitary gland and the percutaneous gasserian ganglion procedure.

Coil embolisation of multiple cerebral aneurysms with lateral type I persistent primitive trigeminal artery: A case report and literature review

The primitive trigeminal artery is an anastomotic vessel of the carotid-basilar artery system that occurs only transiently during the embryonic period. Persistent primitive trigeminal artery occurs in approximately 0.1-0.6% of the population. Here, we report the case of a 60-year-old woman with Fisher II grade subarachnoid haemorrhage. Computed tomography angiography demonstrated a lateral, Saltzman type I persistent primitive trigeminal artery with three cerebral aneurysms, including one anterior communicating artery aneurysm, one suspicious right anterior choroidal artery aneurysm and one distal basilar artery aneurysm supplied by the persistent primitive trigeminal artery. All three aneurysms were treated with coil embolisation. At the 8-month follow-up, the anterior communicating artery aneurysm had a neck remnant, the other two aneurysms exhibited complete occlusion. Persistent primitive trigeminal artery with multiple cerebral aneurysms is extremely rare, and only seven cases of persistent primitive trigeminal artery with multiple cerebral aneurysms have previously been reported in publications that included information on treatment. Most aneurysms were treated by open surgery. This is the first report of coil embolisation treatment of multiple aneurysms in persistent primitive trigeminal artery patients with follow-up results, and provides relevant and valuable information about the persistent primitive trigeminal artery and the endovascular treatment of multiple aneurysms in persistent primitive trigeminal artery patients.

Right persistent trigeminal artery variant (PTAV) and tiny left PTA associated with bilateral ophthalmic arteries arising from the cavernous segments of the internal carotid arteries

Persistent trigeminal artery (PTA) and its variant (PTAV) are the most prevalent types of carotid-vertebrobasilar anastomosis, but bilateral anastomoses are exceedingly rare. We report a case of a right PTAV and tiny left lateral-type PTA from which the cerebellar artery (presumed anterior inferior cerebellar artery) arose. And also, bilateral ophthalmic arteries arose from the cavernous segments of the internal carotid arteries and entered the orbits via the superior orbital fissures. Selective cerebral angiography, especially 3-dimensional angiography, is superior to magnetic resonance (MR) angiography to identify rare variations of the cerebral arteries. Careful observation of MR angiographic source images is important for identifying unique arterial coursing.