Advanced imaging techniques using magnetic resonance (MR) imaging and multidetector-row computed tomography (CT) enable visualization of minute intracranial vascular structures, which can be crucial for neurosurgical planning. MR angiography using high-field MR scanners with magnetization transfer pulses or CT angiography using high-performance CT scanners can readily depict major perforating arteries and distal cortical arteries. Additionally, phase contrast MR venography, time-resolved MR angiography, susceptibility-weighted imaging, contrast-enhanced gradient-echo, or CT angiography with appropriate postprocessing methods can visualize medullary veins, deep veins, cortical veins, and dural sinuses.

  In surgical planning for brain tumor, it is extremely important to identify the location and route of blood vessels. Thus, it is necessary to understand the special features and properties of individual imaging modalities because they provide valuable detailed information about blood vessels. In addition, it should be noted that the purpose of vascular imaging in this context is not to diagnose the pathology, but to acquire information required for surgical planning. Determining tumor margins, recognizing atypical vasculature, and identifying vessels traveling on or near the route of surgical approach are the primary focus in preoperative assessment for brain tumor surgery. Three-dimensional (3D) fusion imaging, which combines data from multiple imaging modalities, is useful for cases involving multiple blood vessels.

  In this article, we introduce clinical cases and review the vascular visualization capability, limitations, and features of medical imaging, and the utility of 3D fusion imaging in surgical planning for brain tumor surgery.

  A thorough knowledge of the functional vascular anatomy of the brain is becoming increasingly required in neuro-interventional procedures. Similarly, this knowledge is also required in neurosurgery, especially when a particular artery or vein is to be sacrificed during surgery. Permanent occlusion of a major artery can be challenged by a balloon occlusion test, but for venous sacrifice, such a procedure is practically not applicable. Up to now, reliable methods to judge the safety of such destructive procedures were lacking. Knowledge of the basic angioarchitecture of the cerebral veins, in other words, the “functional anatomy of the cerebral veins” may help us to better understand the safety or risk of sacrificing cerebral veins. Today, 3D-CT angiography, digital subtraction angiography and cone-beam CT provide detailed information on the precise cerebral venous anatomy to help us understand the functional venous anatomy and to make informed decisions.

  It is very important to consider the phylogenetic aspect of the functional vascular anatomy, collateral circulation and vascular variations affecting the brain and spinal cord. The brain is supplied by two pairs of internal carotid and vertebral arteries, connected by the circle of Willis. During the closure of the neural tube, primordial endothelial blood containing channels are established. From these all other vessels, arteries, veins and capillaries are derived. At stage 12, capital venous plexuses, the capital vein and three aortic arches are present. The internal carotids develop early (stages 11-13), followed by the posterior communicating artery, the caudal branch of the internal carotid at stage 14, the basilar and vertebral arteries (stage 16), the main cerebral arteries (stage 17) and finally the anterior communicating artery, thereby completing the circle of Willis. Bilaterally, longitudinal arteries are established at stage 13 and connected with the internal carotids by temporary trigeminal, otic and hypoglossal arteries. The development of the vascular system of fetus resembles the morphology of fish’s vascular system in a certain stage of the embryological stage. In the zebra fish model, branchial artery, trigeminal artery and longitudinal neural axis that is the future’s anterior spina artery and basilar artery are well observed. The mechanism and the phylogenetic aspect of the vascular anatomy are reviewed.

  Precise knowledge of vascular anatomy is of extreme importance not only for neurosurgery but also for neuroendovascular treatment. In certain endovascular procedures such as dural arteriovenous fistula or skull base tumor embolization, we need to be able to predict the anastomosis which may not be visible on the angiogram using knowledge of anatomy in order to avoid complications.

  Arterial anastomosis comprises embryonically segmental artery anastomosis and anastomosis which share common territory. In this article, the arterial anastomosis around the orbit, the cavernous sinus, the posterior fossa and the craniocervical junction is described in detail.

  Avoiding ischemic complications in perforating branches is an important task in cerebrovascular direct surgery. While using various intraoperative support systems, it is most important to become familiar with the cerebrovascular anatomy. With a focus on controversial issues such as ischemic tolerance during ‘blind-end’ hypoperfusion, we review and discuss the cerebrovascular anatomy of important vessels, including the central retinal artery, the anterior thalamoperforating artery, the anterior choroidal artery, the superior hypophyseal artery and the perforating branches of the anterior communicating artery.

  Adjustable pressure shunt systems have been widely employed for the treatment of patients with hydrocephalus. However these systems, with intrinsic permanent magnets, result in strong distortion artifacts on magnetic resonance (MR) images. In this study, we compared these MR imaging artifacts under different valve pressures.

  We attached Aesculap-Miethke^® ProGAV 2.0^® shunt system to the temporal scalp of a healthy volunteer, parallel to the body axis. He underwent a 3T MR imaging examination with valve pressures of 5, 11, and 17 cmH₂O. The MR imager was SIGNA Pioneer, Ver. PX25.0 made by GE Healthcare.

  The largest artifact was observed at the pressure of 5 cmH₂O, followed by 11 cmH₂O. The smallest artifact was observed at 17 cmH₂O.

  Interference between the strong magnetic field of the MR imager and the weaker magnetic field of permanent magnets in the adjustable shunt system may explain the difference of the artifact size. The artifact was largest when the outer side magnetic field made by the permanent magnet inside the shunt system was opposite to the magnetic field made by the superconductive magnet of MR scanner.

  The size of ProGAV 2.0^® adjustable shunt system artifact depends on the adjusted valve pressure. We conclude that changing valve pressure before an MRI examination is one way to reduce these shunt system artifacts.

  A 75-year-old man was referred to our hospital following the sudden onset of a speech disorder. The patient’s neurological examination indicated severe motor aphasia and computed tomography (CT) demonstrated a low-density area with a sharp margin in the left frontal lobe. A magnetic resonance image (MRI) revealed a hemorrhagic change in the center of the lesion with linear and spotty enhancement within the lesion. Working under a preoperative diagnosis of malignant glioma with intratumoral hemorrhage, a craniotomy was performed. The histological diagnosis was diffuse astrocytoma without any evidence of necrosis or endothelial proliferation. It is relatively uncommon for diffuse astrocytoma to manifest intratumoral hemorrhage. In this case, a focal increase in the density of tumor cells and microvessels was observed in the hemorrhagic regions. Such situations are thought to contribute to intratumoral hemorrhage even in cases of diffuse astrocytoma.