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Radiol Case Rep
Radiol Case Rep
Radiology Case Reports
1930-0433
Elsevier

S1930-0433(24)00864-1
10.1016/j.radcr.2024.08.082
Case Report
Primitive proatlantal intersegmental artery associated with moyamoya disease: A case report
Yu Jinlu jlyu@jlu.edu.cn

Department of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021, China
07 9 2024
12 2024
07 9 2024
19 12 55595564
1 6 2024
14 8 2024
16 8 2024
© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.
2024

https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Primitive proatlantal intersegmental artery (PPIA) is rare and can be divided into types I and II. PPIAs can be associated with some anatomical variations and vascular diseases. However, no case of PPIA combined with moyamoya disease (MMD) has been reported. Here, we reported such a case. A 54-year-old man experienced headache for 1 month. The results of the neurological examinations were unremarkable. Magnetic resonance angiography and digital subtraction angiography revealed a right type I PPIA with MMD. The PPIA serves as an important collateral path for MMD patients. Because the patient only experienced headache, he was discharged and underwent follow-up observation. This case indicates that, rarely, PPIA can be associated with MMD and serve as a collateral vessel for MMD patients.

Keywords

Primitive proatlantal intersegmental artery
Moyamoya disease
Association
Digital subtraction angiography
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pmcIntroduction

Primitive proatlantal intersegmental artery (PPIA) is rare. It can be divided into types I and II. Type I PPIA arises from the internal carotid artery (ICA), and type II PPIA arises from the external carotid artery (ECA); both types join the vertebral artery (VA) [1]. PPIAs can be associated with several vascular conditions, including other primitive carotid‒basilar anastomoses, intracranial aneurysms, arteriovenous malformations, vein of Galen malformation and dural arteriovenous fistulas [[2], [3], [4]]. However, a case in which PPIA is combined with moyamoya disease (MMD) has never been reported.

Case presentation

A 54-year-old man presented with mild and intermittent headache for 1 month. He was of Han Chinese nationality, and recently, he had developed hypertension for 2 years and had always taken medication. The hypertension was well managed. On admission, on physical examination, his limbs had grade V muscle strength. No remarkable neurological examinations were detected. Magnetic resonance (MR) imaging revealed no apparent ischemic changes in the brain but only encephalatrophy (Fig. 1). MR angiography revealed MMD of the bilateral intracranial ICAs (Fig. 2). Digital subtraction angiography revealed right type I PPIA with MMD (Fig. 3). Because the patient experienced only headache and no ischemic changes on MR, he was discharged and underwent follow-up observation. Analgesic medication therapy was suggested for when headache was unbearable.Fig. 1 MR images. (A) T1WI (left panel), T2WI (middle panel) and DWI (right panel) MR sequences showing no apparent brain ischemic changes; encephalatrophy is shown. (B) Posterior anterior (left panel), lateral (middle panel) and superior inferior (right panel) views of MR angiography showing moyamoya disease changes in the region of the bilateral MCAs and left hypoplastic VA (left panel); posterior circulation is supplied to the anterior circulation via collateral circulation from the PCA (asterisks). Abbreviations: L, left; MCA, middle cerebral artery; MR, magnetic resonance; PCA, posterior cerebral artery; VA, vertebral artery.

Fig 1:

Fig. 2 DSA images. (A) Anterior posterior (left panel) and lateral (middle panel) views of the DSA image of the left common carotid artery showing left MMD of the intracranial vessel; lateral view of the DSA image of the left ECA (right panel) showing no anastomosis between the ECA and ICA. (B) Anterior posterior (panel number 1) and lateral (panel number 2) views of the DSA image of the right common carotid artery showing right MMD of the intracranial vessel; an aberrant artery (arrows) can be seen; DSA image (panel number 3) showing the aberrant artery (arrow) arising from the ICA; DSA image of the carotid artery (panel number 4) showing brain vessels supplied by the right ICA and the aberrant artery; DSA image of the right ECA (panel number 5) showing no anastomosis between the ECA and ICA. Abbreviations: DSA, digital subtraction angiography; ECA, external carotid artery; ICA, internal carotid artery; L, left; MMD, moyamoya disease; R, right.

Fig 2:

Fig. 3 PPIA images. (A) Lateral (panel number 1) and posterior (panel number 2) views of the DSA image of the right common carotid artery with more bone reconstruction showing that the aberrant artery conformed to the definition of the PPIA (arrows). The PPIA arose from the ICA and entered the posterior fossa through the foramen magnum; DSA image with less bone reconstruction (panels 3 and 4) showing that the PPIA (arrows) extended to the VA. (B) Three-dimensional subtracted DSA image of the anterior posterior (left panel) and lateral (right panel) views showing the intracranial vessels supplied by the right carotid artery. Abbreviations: C1-3, First to third vertebra; DSA, digital subtraction angiography; ICA, internal carotid artery; L, left; PCA, posterior carotid artery; PPIA, persistent proatlantal intersegmental artery; R, right; VA, vertebral artery.

Fig 3:

Discussion

Four embryonic primitive carotid‒vertebrobasilar anastomoses may persist into adulthood due to failed involution (Fig. 4), including the primitive trigeminal artery (PTA), primitive otic artery (POA), primitive hypoglossal artery (PHA), and PPIA. [5]. These anastomoses have an overall prevalence of 0.1%-1.0%. [6]. Among them, PTA is the most common (0.1%-0.6%), followed by PHA (0.02%-0.10%), POA and PPIA. There are 2 types of PPIAs, and Lasjaunias et al. described them in detail. [7]. In type I PPIA, the basilar system originates from the cervical ICA. It joins the posterior fossa via the first cervical space. Specifically, type I PPIA arises from the ICA at the level of C2-3, avoiding the transverse foramen of the cervical vertebrae and extending directly upward into the occipitoatlantal space. It travels intracranially through the foramen magnum and joins the ipsilateral VA. In type II PPIA, the basilar artery originates from the ECA; it joins the posterior fossa via the second cervical space. Specifically, type II PPIA arises laterally from the ECA; it runs into the cervical canal from C2 onward to C1 and perforates the dura at the C1 space, similar to the conventional VA; it subsequently anastomoses ventrally to the medulla with the VA to form the basilar artery. PPIAs are often unilateral, and bilateral PPIAs are rare [2]. In our case, the PPIA was type I.Fig. 4 Primitive carotid-vertebrobasilar anastomoses. (A) DSA image of the ICA (left panel) showing the PPTA from the ICA; CTA image of the oblique view (middle panel) showing that the PcomA (arrow) connects the anterior and posterior circulations; CTA image of the posterior anterior view (right panel) showing that the PPTA (arrow) connects the ICA and BA. (B) Unsubtracted DSA image of the carotid artery (left panel) showing the PHA from the ICA at the C2 level; CTA image of the inferior superior view (middle panel) showing the PHA (arrow) in the hypoglossal canal; CTA image of the superior oblique view (right panel) showing the PHA (arrow) passing through the hypoglossal canal and extending to the VA. (C) DSA image of the common carotid artery (left panel) showing the VA (arrow) from the common carotid artery; CTA image of the anterior oblique view (middle panel) showing the VA (arrow) from the common carotid artery; the arrowhead indicates the aberrant subclavian artery; lateral view of the CTA image (right panel) showing the VA entering the transverse foramen at the C4 level (arrow). Abbreviations: BA, basilar artery; C2, second vertebra; C4, fourth vertebra; CTA, computed tomography angiography; DSA, digital subtraction angiography; ICA, internal carotid artery; PHA, primitive hypoglossal artery; PPTA, persistent primitive trigeminal artery; VA, vertebral artery.

Fig 4

PPIA may be accompanied by VA agenesis. It plays an important role in maintaining the hemodynamic balance of the brain circulation. PPIA can act as the path of collateral circulation in ICA stenosis or dysplasia. Owing to arteriosclerotic stenosis of the PPIA, infarction or insufficiency of the posterior circulation can occur [8,9]. In addition, in treating some vascular diseases, such as VA angioplasty, aneurysm coiling or mechanical thrombectomy, PPTA can act as a therapeutic channel for procedures [[10], [11], [12], [13], [14]].

PPIA can be associated with some anatomical variations or involved in several vascular diseases, such as arteriovenous malformation, other persistent carotid‒basilar anastomoses, vein of Galen malformations, intracranial aneurysms, and dural arteriovenous fistulas [[2], [3], [4]]. However, there are no reports on the association between PPIA and MMD. In this case, the cause was unclear. Perhaps MMD was associated with PPIA by mere chance. There may also have been a congenital factor. The period when the PPIA disappears at the embryonic stage (5-14 mm) almost corresponds to the period (11-14 mm) in which the vascular state is similar to that of MMD. Therefore, there is a close relationship between MMD and PPIA [15]. When both coexist, PPIA is compatible with MMD and plays an important role because it provides a collateral pathway for the vertebrobasilar system.

In some MMD patients, ECA-ICA revascularization may be necessary to prevent brain ischemia and hemorrhage [16,17]. In our study, the patient was asymptomatic, and conservative treatment and follow-up were suggested.

Conclusion

This case indicates that, rarely, PPIA can be associated with MMD and serve as a collateral vessel for MMD patients. Therefore, PPIA is highly important in MMD.

Patient consent

A written and informed consent was obtained from the patient for publication of this case report.

Author contributions

Jinlu Yu contributed to the study conception and design, wrote the draft of the manuscript, and read and approved the final manuscript.

Ethics approval and consent to participate

Ethics approval was not required by the authors' institution, as the present study is a case report. Informed signed consent to participate was obtained from the patient.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Competing Interests: The authors declare no competing interests.

Acknowledgments: None.
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