The micro-anatomical data obtained may be useful for neurosurgeons when operating at the base of the brain, as well as for a neurological and radiological evaluation of the perforators in the occlusive cerebrovascular disease, or in the cases of an aneurysm, arteriovenous malformation (AVM) or tumour presence.

No abstract

Dear Editor, I would like to thank Matthieu Delion and his colleagues for their compliments regarding our article [1]. At the same time, I am sorry for having not cited their valuable paper [2] on the insular branches of the middle cerebral artery.In general, there are some discrepancies in the terminology and definition of the insular and perforating branches. As we mentioned in our article, there are three main types of the branches of the cerebral arteries: the leptomeningeal, perforating and choroidal [3]. The superficial leptomeningeal vessels give rise to the penetrating branches, i.e. the cortical, subcortical and medullary twigs; the latter of which supply most of the white matter of the cerebral hemispheres, i.e. the centrum semiovale and the corona radiata [4]. On the other hand, the deep perforating vessels mainly originate from the basal cerebral arteries and supply the central hemispheric region, including the basal ganglia and the internal capsule. Accordingly, the mentioned long insular arteries, which arise from the M2 and M3 segments of the MCA, have nothing to do with the perforating vessels of the MCA from both the morphological aspect and the region of supply. These long insular vessels simply belong to the penetrating (medullary) twigs, which were not the subject of our article.As regards the short and medium-sized insular vessels, some of them can be classified as the Batypical^perforators. However, we presented only the typical perforating arteries, i.e. those with certain common features, as was clearly described in our paper. For that reason, we did not mention the atypical perforators, such as those to the claustrum, the cerebellar roof nuclei and the hypothalamus.In any case, I am grateful to Delion and co-workers for their comment on our article, and for presenting the findings of their research.Conflicts of interest None.

There is scarce data in the contemporary literature regarding the correlation of the microanatomy of the perforating arteries, their atherosclerosis, and the ischemia in their territory. In order to examine, at least partially, those parameters, the perforating arteries of 12 brains were microdissected or their vascular casts were obtained. In addition, 30 specimens of the perforators were used for a histological and immunohistochemical study. Finally, radiological images of 14 patients with deep cerebral infarcts were examined following a selection among 62 subjects. It was found out that certain groups of the perforators ranged in number between 0 to 11 (1.1-8.4 on average). In addition to the origin from the parent vessels, some of the perforators also arose from the leptomeningeal branches. Occlusion of such a branch may result in both a superficial and a deep ischemic lesion. Besides, the common stems of certain perforators supplied both right and left portions of the corresponding brain regions. Occlusion of such a common trunk leads to bilateral infarction. The atherosclerosis of the perforating vessels, which was found in one third of the specimens, is the basis for the ischemic lesions development on their territory. Among the 62 patients with ischemic lesions, 14 had a deep cerebral infarcts, most often within the thalamus, as well as on the territory of the middle cerebral and the anterior choroidal artery perforators of the hemispheres. Our study showed that a strong correlation exists between certain microanatomical features, atherosclerosis, and region of supply of the perforating arteries, on the one hand, and location of the ischemic lesions on the other hand.