Background: Despite advances in understanding various risk and prognostic factors, spontaneous intracerebral hemorrhage is connected to very high morbidity and mortality, while the therapy is mainly supportive. Understanding of the pathophysiology of initial hematoma expansion is limited due to insufficient clinical data and lack of a suitable animal model. Methods: We injected 40 anatomic specimens of the basal ganglia with contrast medium, scanned them with a micro-computed tomography scanner and analyzed the results of radiological studies, direct and histological examinations. Results: In 9 cases, micro-computed tomography and histological examinations revealed contrast medium extravasations mimicking intracerebral hematomas. The artificial hematomas spread both proximally and distally along the ruptured perforator and its branches in the perivascular spaces and detached the branches from the adjacent neural tissue leading to destruction of the tissue and secondary extravasations. Moreover, some contrast extravasations skipped to the perivascular spaces of unruptured perforators, created further extravasation sites and aggravated the expansion of the artificial hematoma. There was no subarachnoid extension of any artificial hematoma. Conclusions: We postulate that a forming basal ganglia intracerebral hematoma spreads initially in the perivascular space, detaches the branches from the neural tissue and causes secondary bleeding. It can also skip to the perivascular space of a nearby perforator. The proposed mechanism of hematoma initiation and formation explains extent of damage to the neural tissue, variability of growth in time and space, creation of secondary bleeding sites, and limited usefulness of surgical interventions. The model is reproducible, the extent of the artificial hematoma can be easily controlled, the rupture sites of the perforating arteries can be determined, and preparation of the model does not require specialized, expensive equipment apart from the micro-computed tomography scanner.

Cerebral blood flow constitutes a critical area of interest for neurologists, neurosurgeons, and interventional radiologists as a social burden related to ischemic stroke, hemorrhagic stroke, and vascular dementia is expected to intensify. There is a great need to develop new and effective therapies, therefore deepening understanding of cerebrovascular anatomy, physiology, and pathology is crucial. The main aim of the study was to develop a comprehensive classification of the pontine arteries considering their typology, relations to the cranial nerves, branching schemes, and superficial pontine blood supply areas. We prepared 100 anatomical specimens of the human brainstem with the basilar artery, the pontine arteries, and the terminal perforating arteries. With the use of microsurgical microscope, we analyzed morphometry of the basilar artery, origins, courses, and branching patterns of the pontine arteries as well as distribution of the terminal perforators in relation to pontine superficial vascular areas and the cranial nerves. Additionally, we studied presence of pontine branches of the superior cerebellar artery (SCA) and anterior inferior cerebellar artery (AICA). Repetitive branching patterns, origins, and courses led us to distinguish five types of the pontine arteries: type 1—the paramedian branches, type 2—the short circumflex branches, type 3—composition of the paramedian and the short circumflex branches, type 4—long circumflex branches, and type 5—median branches penetrating the pons along the basilar sulcus. Types 1, 2, and 4 were described in the literature previously, but the classification did not include the median branches (the most prevalent branches) and frequently occurring combinations of the types 1 and 2. There were seven pontine arteries on both sides on average that presented the following general pattern: the first pontine artery below the SCA is a type 4 vessel called the posterolateral pontine artery and it is followed by a type 2 vessel—the superolateral pontine artery; the next three arteries represent the types 1, 2, and 3 and supply most of the ventral pontine surface; the sixth artery—the anterolateral pontine artery—is a short circumflex branch and the seventh artery, originating below the AICA, represents long circumflex arteries. Occlusion of each of the abovementioned vessels relates to a specific pontine vascular syndrome. As explained by the phylogenesis and ontogenesis of the central nervous system, the pontine arteries are subject to variability. The SCA and the AICA took part in the pontine blood supply in 2.5% and 12.5% of cases, respectively, therefore neurovascular interventions involving the SCA, or the AICA may lead to pontine ischemia. Contact of the pontine arteries with the cranial nerves depends on the vessel type and origin location.

Background and Purpose The pathogenesis of neurovascular diseases and various types of dementia is tightly connected to cerebral circulation. An area that requires further exploration is the system of deep cerebral perforating arteries—arteries branching directly from high-pressure intracranial arteries, supplying vital neural structures such as the internal capsule, and characterized by a diameter of well below 1 mm, which makes them difficult to visualize with standard radiological examinations. This study aimed to analyze the morphology of the perforator origins, which constitute connection points between high-pressure intracranial arteries and microcirculation.Methods Twenty-three human basal ganglia specimens with the middle cerebral artery (MCA, including 172 perforating arteries) and ten brainstem specimens with the basilar artery (BA, including 162 perforating arteries) were prepared and scanned using microcomputed tomography. The geometry and structure of the perforating arteries were analyzed using radiological images and additional histological studies.Results The ostia of the perforating arteries were ellipsoidal in shape with median stenosis severity of 23% and 20% for MCA and BA perforators, respectively. The local narrowing structure was typical of neointimal hyperplasia. Statistical analysis revealed that the severity of stenosis may be related to age and cardiovascular health.Conclusion Origins of the deep cerebral perforators are locally narrowed by neointimal hyperplasia, which may be a protective mechanism to adjust high blood pressure to the microcirculation. The narrowings may lead to chronic hypoperfusion and play a role in the pathophysiology of cerebral small vessel disease.

The cerebral circulation is a common site of vascular lesions and concurrent hemodynamic accidents, which often lead to serious neurological disabilities. Recent advances in understanding pathogenesis, improving diagnostics and developing new treatment methods for these conditions result from an interdisciplinary approach to the problem - linking clinical sciences, basic medical sciences and hemodynamical analyses. Most common techniques used in such studies include computational fluid dynamics, which allows for development of 3D models of cerebral vasculature, basing on radiological studies. However, these methods remain flawed, mainly because of their spatial resolution, which is not high enough to visualize the smallest arterial branches (perforating branches) in the models. That leaves the perforators (<1.0 mm) out of most of the contemporary studies, whilst their clinical importance is widely recognized in clinical practice. Obstruction of these vessels by atherosclerotic plaques, thrombi or implantation of flow diverting stents may result in neurological complications such as paralysis or coma. Our research team has recently developed a new method of creating 3D models of the cerebral arterial system based on anatomical specimens and micro computed tomography (micro-CT). We have infused fresh brainstem vasculature specimens with contrast medium, subsequently scanned them using an industrial-grade micro-CT system and finally, created spatial models, which included branches of diameter less than 0.1 mm. None of the current methods have been able to produce models of detail as high as this, which allows us to presume, that our procedure may open up new opportunities for hemodynamical studies within cerebral circulation and beyond.

Background: Standard computed tomography (CT) images have earned a well-established position in neuroimaging. Despite that, CT is somehow limited by its resolution, which does not enable to distinctively visualize structures smaller than 300 um in diameter. Perforating arteries, most of which measure 100-400 um in diameter, supply important subcortical structures (thalamus, basal ganglia, internal capsule). Consequently, pathologies affecting these vessels (e.g. lacunar strokes) can have a devastating clinical outcome. The aim of our study was to assess standard CT’s ability to visualize perforators and compare it with microscopical and micro-CT pictures. Materials and methods: We have obtained six brainstem and seventeen basal ganglia specimens. We infused them with barium sulphate contrast medium administered into either vertebral or internal cerebral artery. After that, the specimens were fixed in formalin and subsequently a series of CT, micro-CT and microscopical examinations were performed. Results: The median number of visualized perforators in brainstem and basal ganglia specimens was 8 and 3, respectively for CT and 18 and 7 for micro–CT (p < 0.05). Standard CT failed to clearly visualize branching points and vessels smaller than 0.25-0.5 mm (1-2 voxels) in diameter. Parallel vessels, like lenticulostriate arteries could not be differentiated in standard CT due to their proximity being smaller that the resolution. Conclusions: Basing on our results, we infer that CT is a poor modality for imaging of the perforators, presenting both quantitative and qualitative flaws in contrast with micro-CT. Background: Standard computed tomography (CT) images have earned a well-established position in neuroimaging. Despite that, CT is somehow limited by its resolution, which does not enable to distinctively visualize structures smaller than 300 um in diameter. Perforating arteries, most of which measure 100-400 um in diameter, supply important subcortical structures (thalamus, basal ganglia, internal capsule). Consequently, pathologies affecting these vessels (e.g. lacunar strokes) can have a devastating clinical outcome. The aim of our study was to assess standard CT’s ability to visualize perforators and compare it with microscopical and micro-CT pictures. Materials and methods: We have obtained six brainstem and seventeen basal ganglia specimens. We infused them with barium sulphate contrast medium administered into either vertebral or internal cerebral artery. After that, the specimens were fixed in formalin and subsequently a series of CT, micro-CT and microscopical examinations were performed. Results: The median number of visualized perforators in brainstem and basal ganglia specimens was 8 and 3, respectively for CT and 18 and 7 for micro–CT (p < 0.05). Standard CT failed to clearly visualize branching points and vessels smaller than 0.25-0.5 mm (1-2 voxels) in diameter. Parallel vessels, like lenticulostriate arteries could not be differentiated in standard CT due to their proximity being smaller that the resolution. Conclusions: Basing on our results, we infer that CT is a poor modality for imaging of the perforators, presenting both quantitative and qualitative flaws in contrast with micro-CT.

Introduction: The article describes the process of converting a large multi-specialized hospital into one dedicated to COVID-19 patients, and present established standards of work organization in all the wards and training system of the medical and supporting staff. The several weeks pandemic...