Figure 1
3D Time of Flight (TOF) MRA of the Circle of Willis showing a small focal area of high signal close to the junction of the ACoA and right anterior cerebral artery. This raised the possibility of a small aneurysm of the ACoA.
Magnetic Resonance Angiogram (MRA) and Computed Tomography Angiogram (CTA) appearance of Fenestration of the Anterior Communicating Artery.
SectionCardiovascular
Case TypeAnatomy and Functional Imaging
AuthorsAzian Abd. Aziz1, Elhamy Kamal Bekhit2 1Department of Radiology, Kulliyyah of Medicine, International Islamic University Malaysia, 25000 Kuantan, Pahang, Malaysia 2Department of Medical Imaging, The Royal Children’s Hospital Melbourne, Flemington Road, Parkville, Vic 3052, Australia
Connected authors
15 years, female
Clinical History
Fenestration of the cerebral vessel is a rare congenital variation. The knowledge of the appearances of this variation is important since it may mimic aneurysm or
vascular malformation. The appearance of fenestration of the anterior communicating artery (ACoA) on MRA and CTA is demonstrated.
Imaging Findings
A 15 year old girl with headache underwent MRI and MRA brain. No lesion is detected in the brain but an abnormality of the anterior communicating artery (ACoA) was incidentally identified on the MRA
(Figure 1). Because there was a concerned for a possibility of an aneurysm of the ACoA on MRA, a CTA of the Circle of Willis was performed to further delineate this vessel. CTA allows the ability for
post processing and manipulation of images in different planes as compared to a conventional digital subtraction angiography (DSA). From the CTA raw data, 1mm slices with a 0.7 mm increment were
loaded into InSpace SIEMENS software to produce a 3D volume rendered technique (VRT) image and using a vessel setting the final image was created. No aneurysm was detected but the appearance is
consistent with fenestration of the ACoA as clearly demonstrated in Figure 2. The schematic illustration is shown in Figure 3.
Discussion
Many previous studies have shown the association between fenestration of the cerebral arteries with intracranial aneurysm, arteriovenous malformation and other developmental venous anomaly [1].
Various figures on the incidence of fenestration of the anterior cerebral artery (ACA) were reported by several authors in the past ranging from 0.1 - 7.2% in autopsies and in many cases fenestration
occurred at the horizontal segment of ACA [2,3]. It has also been reported that the incidence of fenestration of the anterior communicating artery (ACoA) was 7.5 – 40% in autopsies [3, 4]. The
anatomical variations of the anterior cerebral circulation may not have serious clinical significance; however, knowledge that these variations exist is of great importance since it may be mistaken
for aneurysm or vascular malformation on Magnetic Resonance Angiogram (MRA) and can influence interventional procedure or avoid unnecessary surgical procedure. MRA complemented by CTA of the Circle
of Willis was able to eloquently demonstrate the fenestration of the ACoA without performing a conventional DSA which is known to have a significant risk of neurological impairment post procedure.
Differential Diagnosis List
Fenestration of the anterior communicating artery (ACoA).
Final Diagnosis
Fenestration of the anterior communicating artery (ACoA).
References
[1] Uchino A, Kato A, Abe M, Kudo S. Association of cerebral arteriovenous malformation with cerebral arterial fenestration. European Radiology 2001; 11(3):493-6. (PMID: 11288858)
[2] Ito J, Washiyama K, Kim CH, Ibuchi Y. Fenestration of the anterior cerebral artery. Neuroradiology 1981; 21(5):277-80. (PMID: 7266865)
[3] Okahara M, Kiyosue H, Mori H, Tanoue S, Sainou M, Nagatomi H. Anatomic variations of the cerebral arteries and their embryology: a pictorial review. European Radiology 2002; 12(10):2548-61. (PMID: 12271398)
[4] Gurdal E, Cakmak O, Yalcinkaya M, Uzun I, Cavdar S. Two variations of the anterior communicating artery: a clinical reminder. Neuroanatomy 2004; 3:32-34.
Case information
| URL: | https://www.eurorad.org/case/6019 |
| DOI: | 10.1594/EURORAD/CASE.6019 |
| ISSN: | 1563-4086 |
Figure 2
3D VRT CTA image clearly demonstrate an interlacing network of vessels consistent with fenestration of the ACoA. No aneurysm was identified. The anterior, middle and posterior cerebral arteries are normal.
Figure 3
Schematic illustration showing the fenestration of the ACoA (arrow).
3D Time of Flight (TOF) MRA of the Circle of Willis showing a small focal area of high signal close to the junction of the ACoA and right anterior cerebral artery. This raised the possibility of a small aneurysm of the ACoA.
3D VRT CTA image clearly demonstrate an interlacing network of vessels consistent with fenestration of the ACoA. No aneurysm was identified. The anterior, middle and posterior cerebral arteries are normal.
Schematic illustration showing the fenestration of the ACoA (arrow).
