Книги по МРТ КТ на английском языке / Neurovascular anatomy in interventional neuroradiology Krings et al 2015
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
15 The Lenticulostriate Arteries and the Recurrent Artery of
Heubner
15.1 Case Descriptions
15.1.1 Clinical Presentation
A 44-year-old male patient presented with acute subarachnoid hemorrhage.
15.1.2 Radiologic Studies
See Fig. 15.1, Fig. 15.2.
15.1.3 Diagnosis
Anterior communicating artery aneurysm in the setting of congenital hypoplasia of the left internal carotid artery (ICA) and reconstitution of the left middle cerebral artery (MCA) through two enlarged lenticulostriate arteries.
15.2 Embryology and Anatomy
The lenticulostriate arteries are a group of small perforating vessels arising from the proximal segments of the anterior cerebral artery (ACA) and the MCA to supply primarily, but not only, the striatum.
Embryologically, they develop from the lateral striate arteries, a system that arises from the rostral division of the internal cerebral artery, to meet the growing needs of the expanding telencephalic vesicles. This group of arteries will give rise to the lenticulostriate arteries, including the recurrent artery of Heubner (RAH), but will also form the adult MCA. Thus, from
an embryological point of view, the MCA represents an enlarged perforator branch of the ACA. See also Case 14.
As discussed in the previous case, there is a broad range of variations related to the perforators as a result of di ering coalescences during embryonic life for the di erent perforator groups; therefore, they may arise as multiple single small vessels from the parent artery or from a common larger trunk or take over each other’s territory. From medial to lateral, the following groups can be identified: the RAH, the medial lenticulostriate arteries from the ACA, the medial lenticulostriate arteries from the MCA, and the lateral lenticulostriate artery group. These groups can be interconnected with each other and form a rete (the most prominent example of which is the fenestration of the M1 or A1, as discussed in Case 14).
The RAH originates from the A1/A2 junction or in the first few millimeters of the A2 segment in 90% of cases. In only 10% of cases will it arise from the distal A1. The RAH supplies the anterior inferior striatum, anterior limb of the internal capsule, olfactory region, and anterior hypothalamus and is in a hemodynamic balance with the medial lenticulostriate arterial groups. Occasionally, the RAH can be duplicated or missing. The artery has a recurrent path turning laterally, coursing over the A1 (~60%), anterior to the A1 (~35%), and rarely, posterior to the A1 (3%). The territory supplied by the RAH is variable, as it is in balance with the medial lenticulostriate arteries ( Fig. 15.3;Fig. 15.4).
The perforators of the medial lenticulostriate arterial group, which originate from the proximal half of the A1 segment, vary highly in diameter and number, with a mean of eight (range, 2– 15). Approximately half of the medial lenticulostriate arterial
Fig. 15.1 CT in the bone window (a,b), CTA in coronal view (c,d), and 3D reconstruction (e) demonstrate hypoplasia of the left foramen lacerum and the carotid canal (black arrow), indicating congenital ICA hypoplasia. CTA confirms absence of intradural filling of the left ICA and provides evidence for reconstitution of the left MCA via two separate arteries arising from the anterior communicating complex (white arrows). As the source of hemorrhage, a small, broad-based anterior communicating artery aneurysm (black arrowheads) was found. Case is continued in Fig. 15.2.
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
Fig. 15.2 After clip exclusion of the aneurysm, left common carotid artery angiogram in anteroposterior (AP) view (a) confirms ICA hypoplasia. Right ICA angiogram in AP (b), oblique (c), and 3D reconstruction (d,e,f) demonstrates reconstitution of the MCA via two arteries of the anterior communicating complex that run in parallel and from which the perforating lenticulostriate vessels (arrows) arise.
Fig. 15.3 Diffusion-weighted MRI (a,b,c) in a patient with an extensive left Heubner territory infarction demonstrates abnormal signal intensity within the head of the caudate nucleus and the anterior basal ganglia.
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
Fig. 15.4 Right ICA angiogram in AP view in arterial (a) and capillary (b) phases demonstrates the course and supply (capillary blush in b) of the left RAH (arrows).
groups enter the anterior perforating substance and provide flow to the basal ganglia, septum pellucidum, and anterior limb of the internal capsule. The other half will supply the local structures, including the hypothalamus and the optic chiasm.
The lenticulostriate arteries arising from the MCA can be divided into a smaller medial group and a larger lateral group, even though a clear separation between the two groups is only possible in approximately 40% of cases. They are in balance with the lenticulostriate arteries arising from the ACA, creating an equilibrium that mainly involves the medial group.
There are usually between six and 20 lenticulostriate branches per hemisphere. They may arise from a single vessel or a major trunk (so-called candelabra arteries) in 50% of cases, and subsequently divide into individual small arteries. Most commonly, they arise from the posterosuperior aspect of the M1 segment, but in approximately 20% of cases, they can originate from either the superior or inferior divisions of the MCA or, less commonly, from an early cortical branch of the MCA.
From their site of origin, the medial lenticulostriate arteries ascend through the anterior perforated substance, heading
straight to the lenticular nucleus, to supply, together with the medial lenticulostriate arteries from the ACA and the RAH, the anteroinferior portion of the head of the caudate nucleus, the anterior third of the putamen, the anterior limb of the internal capsule, the anterolateral edge of the globus pallidus, the medial aspect of the anterior commissure, and the anterior part of the hypothalamus.
The lateral group describes a sharp posterior and medial recurrent curve in the cisternal segment before entering the lateral two-thirds of the anterior perforated substance. They initially ascend, coursing around and through the lenticular nucleus, and then turn medially through the superior half of the internal capsule, heading toward the caudate nucleus. They will be responsible for the vascularization of the upper portion of the head and the body of the caudate nucleus, the putamen, the lateral segment of the globus pallidus, the lateral half of the anterior commissure, and the superior segments of both limbs of the internal capsule. The blood supply to the structures lateral to the putamen, including the claustrum and the external capsule, is derived from other perforators arising from the insular branches of the MCA ( Fig. 15.5).
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
Fig. 15.5 Variations in the origin of the lenticulostriate arteries: Right ICA angiogram in AP view in early (a) and late (b) arterial phases demonstrates a common trunk for the medial and lateral lenticulostriate group of perforators (arrow), whereas the contralateral left ICA angiogram in early (c) and late
(d) arterial phases shows a dominant RAH (thin double arrows) that gives rise to all perforators on its way laterally, where it anastomoses distally with the main MCA trunk.
15.3 Clinical Impact, Additional
Information and Cases
In the following, a selection of cases is presented that highlight the anatomical importance of the lenticulostriate artery and the RAH in di erent clinical scenarios ( Fig. 15.6; Fig. 15.7;
Fig. 15.8; Fig. 15.9; Fig. 15.10; Fig. 15.11; Fig. 15.12;
Fig. 15.13).
Pearls and Pitfalls
●Embryologically, the anterior perforators arise from the lateral striate arteries from the ACA. Although, classically, three major groups are present (RAH, medial, and lateral lenticulostriate groups), significant variations with common trunks or multiple separate origins from the proximal A2 to the proximal M2 exist.
●The relation between the perforator origins, their territory, and intracranial stenotic lesions is important in estimating the risk of an intervention in the MCA.
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
Fig. 15.6 This 45-year-old male patient with a left frontal arteriovenous malformation (AVM) presented with an intracerebral hemorrhage within the caudate head seen on axial T2-weighted MRI (a,b,c). Given the localized hemorrhage, superselective evaluation of the Heubner artery territory was performed to exclude the possibility of an intranidal aneurysm that would have been regarded as a potential target for embolization. Right ICA angiogram in AP (d) and semioblique (e) views, as well as superselective catheterizations (f) and 3D rotational reconstruction (g,h), demonstrate left Heubner’s artery and its territory, as well as its secondarily induced supply to the more cranially located shunt. Superselective injections fail to show any focal angioarchitectural weak spots. As there was no target for embolization therapy identified, the procedure was aborted.
Fig. 15.7 Right ICA angiograms in AP (a) and oblique (b) views and 3D rotational reconstruction (c) in a 16-year-old female patient demonstrate a micro-AVM, fed by Heubner’s artery (arrows).
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
Fig. 15.8 A 60-year-old man with a large right frontal meningioma, seen on axial T2-weighted MRI (a), was investigated for potential embolization. Right ICA angiogram in AP view in early (b) and late (c) arterial phases demonstrates pial supply to the tumor coming from the right ACA through Heubner’s artery (arrow). Note that an accessory middle meningeal artery arises from the right ophthalmic artery.
Fig. 15.9 MRI diffusion-weighted imaging (a) and left ICA angiogram in AP view in early (b) and late (c) arterial phases demonstrate a medial lenticulostriate artery infarction resulting from a thrombus lodging directly at the origin of the artery supplying the infarcted territory (arrows).
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
Fig. 15.10 Left ICA angiograms in AP view (a) and postcoiling 3D rotational reconstruction (b,c) demonstrate a proximal M1 aneurysm at the origin of the medial lenticulostriate perforators (arrow).
Fig. 15.11 MRI axial T2-weighted (a,b) and T1-weighted (c) images and unenhanced CT (d) demonstrate a ruptured brain AVM. A round flow-void structure (white arrows) adjacent to the hematoma on MRI was confirmed to be a focal aneurysmal outpouching (double black arrows), arising from a left lateral lenticulostriate perforator vessel on the left ICA angiogram in AP view (e).
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
Fig. 15.12 Right ICA (a) and left ICA (b) angiograms in AP view in two different patients demonstrate secondarily recruited supply from the lenticulostriate perforators in an insular (a) and cingulate (b) AVM. This deep supply to brain AVMs represents a potential target for presurgical embolization.
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The Lenticulostriate Arteries and the Recurrent Artery of Heubner
Fig. 15.13 This 48-year-old patient presented with a right caudate head hemorrhage with intraventricular extension seen on unenhanced axial CT (a). Right ICA angiograms in AP view (b) and 3D rotational reconstruction (c,d) performed on admission showed a small prenidal aneurysm (arrow) on the most distal aspect of the secondarily recruited right lateral lenticulostriate artery. After discussion with the vascular neurosurgical team, a decision was made to attempt targeted embolization, which was performed 4 days after the initial angiography. As we were not able to navigate the catheter into the target vessel, a balloon was advanced into the M1, immediately past the origin of the target artery. With balloon inflation, which provided extra support, we were able to navigate the microcatheter into the lateral lenticulostriate artery. Microcatheter injections (e,f) showed that the previously seen pseudoaneurysm was no longer present, presumably because of spontaneous thrombosis. The injections also revealed that the supply to the medial and lateral lenticulostriate territory arose from this single vessel.
Further Reading
[1]Komiyama M, Nakajima H, Nishikawa M, Yasui T. Middle cerebral artery variations: duplicated and accessory arteries. AJNR Am J Neuroradiol 1998; 19: 45–49
[2]Lasjaunias P, Berenstein A, ter Brugge KG. Surgical Neuroangiography. Vol. 1. 2nd ed. Berlin: Springer; 2006
[3]Newton TH, Potts DG. Radiology of the Skull and Brain. Angiography. Vol. 3, Book 2. St. Louis, MO: Mosby; 1974
[4]Takahashi S, Goto K, Fukasawa H, Kawata Y, Uemura K, Suzuki K. Computed tomography of cerebral infarction along the distribution of the basal perforating arteries. Part I: Striate arterial group. Radiology 1985; 155: 107–118
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The Cortical Branches of the Middle Cerebral Artery
16 The Cortical Branches of the Middle Cerebral Artery
16.1 Case Description
16.1.1 Clinical Presentation
A 30-year-old woman was investigated with magnetic resonance (MR) in screening for familial aneurysms, and an incidental left-sided broad-based 8-mm middle cerebral artery (MCA) aneurysm was found. The patient was referred to neurosurgery.
16.1.2 Radiologic Studies
See Fig. 16.1, Fig. 16.2, and Fig. 16.3.
16.1.3 Diagnosis
Acute MCA occlusion with subsequent thrombectomy
16.2 Embryology and Anatomy
Distal to the MCA trunk, the MCA typically splits into two divi- sions—the superior and the inferior trunk—which are in hemodynamic balance and show considerable variations regarding dominance of one trunk over the other (with concomitant annexed territories). The superior division will supply the frontal
Fig. 16.1 Immediately after clipping of an incidental left-sided MCA aneurysm (MR angiography in a), this 30-year-old patient presented with a complete right-sided hemiparesis and aphasia. CTA (b) failed to demonstrate a normal MCA bifurcation, whereas CT perfusion (Time to Peak [TTP] Map in c) showed significant hypoperfusion of her left hemisphere. The patient was immediately reoperated, and the clip was repositioned. On surgical inspection, however, the operator noted that thrombus was present within the MCA bifurcation, and emergency thrombectomy was requested. Injection into the left internal carotid artery (ICA) in early (d) and late (e) arterial and capillary (f,g) phases revealed occlusion of the distal M1 with good filling of the lenticulostriate arteries and excellent collaterals from the ACA territory reconstituting the dominant superior division of the MCA. Case continued in Fig. 16.1.
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