Intracranial arteries (variants)

Twin anterior

cerebral artery anomaly: Azygous ACA with fenestrated right A1 segment. MDCT angiography (coronal section) of intracranial vessels showing fenestration of A1 segment of ACA.

www.eurorad.org • CC by-nc-sa-4.0

Zufallsbefund

einer persistierenden A. trigemina, also einer Verbindung von der A. carotis interna zur A. basilaris, die normalerweise in der Embryonalzeit zurückgebildet wird. Hier finden sich weitere Anomalien: Die A. basilaris ist streckenweise nur sehr schwach ausgebildet. Die A. trigemina mündet nach Abgabe der Aa. cerebelli superiores in die gegenseitige A. cerebri posterior während die andere A. cerebri posterior von der A. communicans posterior gespeist wird. Der Pfeil zeigt auf die von rechts kommende A. trigemina. (Bilder aus einer T1-3D-KM-Serie als Volumenrendering)

Wikipedia • CC BY-SA 3.0

Common and

insightsimaging.springeropen.com • Open Access

Intracranial

arteries (variants) • Basilar artery fenestration - Ganzer Fall bei Radiopaedia

Puyó D, Basilar artery fenestration. Case study, Radiopaedia.org (Accessed on 25 Jan 2023) https://doi.org/10.53347/rID-99191 • CC by-nc-sa 3.0 (modified)

Intracranial

arteries (variants) • Unilateral anterior cerebral artery (A1 segment) aplasia/hypoplasia - Ganzer Fall bei Radiopaedia

Mahmud A, Unilateral anterior cerebral artery (A1 segment) aplasia/hypoplasia. Case study, Radiopaedia.org (Accessed on 25 Jan 2023) https://doi.org/10.53347/rID-78692 • CC by-nc-sa 3.0 (modified)

cerebral artery • Aplastic A1 on MRA - Ganzer Fall bei Radiopaedia

Hacking, C. Aplastic A1 on MRA. Case study, Radiopaedia.org. (accessed on 21 Oct 2022) https://doi.org/10.53347/rID-62595 • CC by-nc-sa 3.0 (modified)

Intracranial

arteries (variants) • Accessory middle cerebral artery - Ganzer Fall bei Radiopaedia

Dawes L, Accessory middle cerebral artery. Case study, Radiopaedia.org (Accessed on 25 Jan 2023) https://doi.org/10.53347/rID-35944 • CC by-nc-sa 3.0 (modified)

Intracranial

arteries (variants) • Primitive trigeminal artery with fetal PCOM - Ganzer Fall bei Radiopaedia

Batta N, Primitive trigeminal artery with fetal PCOM. Case study, Radiopaedia.org (Accessed on 25 Jan 2023) https://doi.org/10.53347/rID-24041 • CC by-nc-sa 3.0 (modified)

Intracranial

arteries (variants) • Anterior cerberal artery fenestration - Ganzer Fall bei Radiopaedia

Knipe H, Anterior cerberal artery fenestration. Case study, Radiopaedia.org (Accessed on 25 Jan 2023) https://doi.org/10.53347/rID-24050 • CC by-nc-sa 3.0 (modified)

cerebral artery • Common variants of the circle of Willis (illustrations) - Ganzer Fall bei Radiopaedia

Hapugoda, S. Common variants of the circle of Willis (illustrations). Case study, Radiopaedia.org. (accessed on 21 Oct 2022) https://doi.org/10.53347/rID-51777 • CC by-nc-sa 3.0 (modified)

Persisitierende

Arteria trigemina links als Zufallsbefund in der CTA. Deutlicher Kalibersprung der A. basilaris an der Einmündung. Linkes Bild Volumen Rendering (Blick von dorsal auf den Clivus), rechts schräg koronare MIP.

Wikipedia • CC BY-SA 4.0

Heubner\"s

artery territory infarction after surgical clipping of an unruptured saccular aneurysm of the left anterior cerebral artery: a case report. MIP image showing the A1-A2 left ACA aneurysm (7 mm in diameter) and another one in the left MCA.

www.eurorad.org • CC by-nc-sa-4.0

Duplicated

middle cerebral artery associated with aneurysm at M1/M2 bifurcation: a case report. a Magnetic resonance angiography showing duplicated middle cerebral artery (arrowheads) on the left and an aneurysm at the M1/M2 junction of duplicated middle cerebral artery (arrow). b Three-dimensional computed tomographic angiography also demonstrating the left duplicated middle cerebral artery and aneurysms at the M1/M2 junction of duplicated middle cerebral artery (arrow) and internal carotid artery top (small arrow)

jmedicalcasereports.biomedcentral.com • CC-by-4.0

Common and

insightsimaging.springeropen.com • Open Access

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. a CTA (VRT 3D reconstructions) reveals aplasia of the left A1 segment of the anterior cerebral artery in a patient with an Acom aneurysm. b Digital subtraction angiography (AP view) of the right ICA verifies the presence of a small Acom aneurysm. Both A2 segments are opacified from this single injection. c Digital subtraction angiography (AP view) of the left ICA. The left A1 segment is absent

insightsimaging.springeropen.com • Open Access

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. a CTA (VRT 3D reconstructions) shows a vessel connecting the ICA with the basilar artery (annotations). b Axial CT image at the level of the hypoglossal canal shows an enlarged vessel piercing the skull base on the left, through the hypoglassal canal, which was also enlarged (black arrow). c CTA (VRT 3D reconstructions) reveals an absent proximal vertebral artery and hypoplastic contralateral vertebral artery (annotations)

insightsimaging.springeropen.com • Open Access

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. CTA (VRT 3D reconstructions) shows a left-sided trigeminal artery joining the basilar artery. The basilar artery (which is relatively hypoplastic, proximal to the connection site) gives rise to the right PCA, while the left PCA arises from the ICA (foetal PCom) (Saltzman’s type II or Weon’s type 3) (annotations)

insightsimaging.springeropen.com • Open Access

Common and

insightsimaging.springeropen.com • Open Access

Zufallsbefund

einer persistierenden A. trigemina, also einer Verbindung von der A. carotis interna zur A. basilaris, die normalerweise in der Embryonalzeit zurückgebildet wird. Hier finden sich weitere Anomalien: Die A. basilaris ist streckenweise nur sehr schwach ausgebildet. Die A. trigemina mündet nach Abgabe der Aa. cerebelli superiores in die gegenseitige A. cerebri posterior während die andere A. cerebri posterior von der A. communicans posterior gespeist wird. Der Pfeil zeigt auf die A. trigemina von rechts kommend. (Bilder aus einer T1-3D-KM-Serie als 8mm-MIP )

Wikipedia • CC BY-SA 3.0

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. CTA (VRT 3D reconstructions) shows a hypoplastic right-sided A1 segment of the anterior cerebral artery (white arrow) in a patient with an Acom aneurysm. Note the presence of a foetal Pcom on the same side (yellow arrow)

insightsimaging.springeropen.com • Open Access

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. a CTA (VRT 3D reconstructions) reveals the presence of an unpaired ACA (conventional type, long segment) (red arrow). b CTA (VRT 3D reconstructions) shows an unpaired ACA (conventional type, short segment) (red arrow)

insightsimaging.springeropen.com • Open Access

Common and

insightsimaging.springeropen.com • Open Access

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. a CTA (VRT 3D reconstructions) shows a proximal basilar artery fenestration (red arrow). b CTA (VRT 3D reconstructions) shows an Acom artery fenestration (red arrow)

insightsimaging.springeropen.com • Open Access

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. a Axial CT image at the level of the cavernous carotids shows occlusion of the left ICA (red arrow) due to atherosclerotic disease. b Coronal reconstruction at the level of the cavernous carotids verifies the occlusion of the left ICA (red arrow) as well as atherosclerotic disease. c CTA (VRT 3D reconstructions) shows the accessory MCA as a vessel coming from the A2 segment of the ipsilateral anterior cerebral artery (red arrow). d Axial MIP image shows the course of the AccMCA (black arrowheads), the anastomotic network (moyamoya type) at the level of the left mid M1 segment (red arrow) as well as the patent peripheral left MCA (black arrow). e CTA (VRT 3D reconstructions) reveals the same configuration and patent peripheral MCA (red arrow)

insightsimaging.springeropen.com • Open Access

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. a CTA (VRT reconstructions) shows a right-sided foetal Pcom (black arrow) with a large aneurysm at the origin of the vessel (yellow arrow). b Digital subtraction angiography (lateral view) of the right ICA shows a foetal Pcom (red arrow) and large aneurysm at the origin of the vessel (black arrow), which cannot be compromised. c Digital subtraction angiography (AP view) of the left vertebral artery. The posterior cerebral artery on the right is not opacified (definition of a foetal Pcom). b Post-embolisation digital subtraction angiography (lateral view) of the right ICA shows good patency of the foetal Pcom (red arrow) and complete obliteration of the aneurysmal sac (black arrow)

insightsimaging.springeropen.com • Open Access

Common and

uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of. a CTA (VRT reconstructions) shows a right-sided foetal Pcom (red arrow). b CT oblique MPR image shows an increased wall thickness (red arrow) and intimal flap (yellow arrow) of the dissected right ICA. c Axial CT image at the level of the third ventricle shows right-sided occipital and posterior parietal lobe infarcts (red arrows)

insightsimaging.springeropen.com • Open Access

Agenesis of

internal carotid artery associated with isolated growth hormone deficiency: a case report and literature review. A MRI angiography time-of-flight (TOF) three-dimensional (3D) technique through the circle of Willis revealed agenesis of the intracranial portion of the left internal carotid artery (ICA). a. 3D TOF in the axial plane at the carotid siphon level shows agenesis of the left ICA. b. 3D TOF in the axial plane for the vertebrobasilar system shows the left vertebral artery and the compensatory hypertrophy. c. MRI angiography maximum intensity projection (MIP) reconstruction in the axial plane reveals agenesis of the intracranial portion of the left ICA. d. MRI angiography MIP reconstruction in the coronal plane highlights hypertrophy in the left vertebral collateral blood flow. e. Sagittal T1W TSE sequence shows adenohypophyseal hypoplasia (height 2.5 mm and width 3.5 mm) with a lack of posterior pituitary hyperintensity

bmcendocrdisord.biomedcentral.com • CC-by-4.0

Intracranial

arteries (variants) • Trifurcated left middle cerebral artery - Ganzer Fall bei Radiopaedia

Puyó D, Trifurcated left middle cerebral artery. Case study, Radiopaedia.org (Accessed on 25 Jan 2023) https://doi.org/10.53347/rID-99198 • CC by-nc-sa 3.0 (modified)

Radiopaedia • CC-by-nc-sa 3.0 • de

Intracranial arterial variants, of which there are many, are collectively common. Their clinical significance may be variable but knowledge and recognition of these variants is fundamental, especially if surgical or endovascular treatments (e.g. for acute stroke, aneurysms or other vascular pathologies) are being considered.