Usefulness of high-resolution 3D multifusion medical imaging for preoperative planning in patients with posterior fossa hemangioblastoma: technical note

Simulation of the occipital transtentorial approach incorporating visualization of the cerebellar tentorium using three-dimensional computed tomography angiography and gadolinium-enhanced T1-weighted magnetic resonance imaging: technical note

The occipital transtentorial approach (OTA) is one of the useful approaches to the lesions of the pineal region, dorsal brainstem, and supracerebellar region. However, a wide operative field is sometimes difficult to obtain due to the tentorial sinus and bridging veins. This study evaluated the usefulness of preoperative simulation of OTA, specifically including the cerebellar tentorium in 9 patients. All patients underwent computed tomography angiography and venography and gadolinium-enhanced three-dimensional T1-weighted magnetic resonance images (Gd-3D-T1WI). The images were fused, and the cerebellar tentorium, vessels, and tumor were manually extracted from Gd-3D-T1WI to obtain the simulation images. Visualization of the cerebellar tentorium could discriminate between bridging veins from the occipital lobe and cerebellum, and recognize the site of bridging to the tentorial sinus and variants which may interfere with the tentorial incision. Simulation of the tentorial incision was also possible based on the relationships between the tumor, tentorial sinus, bridging vein, and cerebellar tentorium. The simulation suggested that safe tentorial incision was difficult in two sides because of the crossed tentorial sinus draining the left basal vein and draining veins from the glioblastoma. The OTA was performed in eight cases, and no difficulty was experienced in the tentorial incision in all cases. The simulation findings of the bridging vein and tentorial sinus were consistent with the intraoperative findings. Preoperative simulation including the cerebellar tentorium is useful for determining the optimum and safe side and required extent of the tentorial incision necessary for tumor resection with the OTA.

Case Report: “Clipping” an Internal Carotid Artery Aneurysm With a Duplicated Middle Cerebral Artery and the Anterior Choroidal Artery Arising From the Dome

Background

A duplicated middle cerebral artery (DMCA) is an anatomical variant that includes duplication of the middle cerebral artery (MCA) and an anomalous vessel originating between the anterior choroidal artery (AChA) and the distal end of the internal carotid artery (ICA). Here, we present a case report of an ICA aneurysm with a DMCA and the AChA originating from the dome, which was successfully treated with clipping.

Case Description

In a 64-year-old man, preoperative angiography revealed an unruptured right ICA aneurysm with a maximum diameter of 4.3 mm, and fusion three-dimensional computer graphics revealed that a DMCA and the AChA originated from the dome. The aneurysm enlarged; therefore, clipping was performed. The closure of the aneurysm while preserving the patency of the DMCA and AChA was identified using intraoperative microvascular Doppler ultrasonography and indocyanine green video angiography. The postoperative course was uneventful, and no ischemic lesions were confirmed on MR imaging.

Conclusion

To the best of our knowledge, this is the first report of an ICA aneurysm with a DMCA and the AChA arising from the dome. In such cases, the anatomy of the DMCA and AChA should be well-characterized before treatment.

Hahn-PCNN-CNN: an end-to-end multi-modal brain medical image fusion framework useful for clinical diagnosis

Background

In medical diagnosis of brain, the role of multi-modal medical image fusion is becoming more prominent. Among them, there is no lack of filtering layered fusion and newly emerging deep learning algorithms. The former has a fast fusion speed but the fusion image texture is blurred; the latter has a better fusion effect but requires higher machine computing capabilities. Therefore, how to find a balanced algorithm in terms of image quality, speed and computing power is still the focus of all scholars.

Methods

We built an end-to-end Hahn-PCNN-CNN. The network is composed of feature extraction module, feature fusion module and image reconstruction module. We selected 8000 multi-modal brain medical images downloaded from the Harvard Medical School website to train the feature extraction layer and image reconstruction layer to enhance the network’s ability to reconstruct brain medical images. In the feature fusion module, we use the moments of the feature map combined with the pulse-coupled neural network to reduce the information loss caused by convolution in the previous fusion module and save time.

Results

We choose eight sets of registered multi-modal brain medical images in four diease to verify our model. The anatomical structure images are from MRI and the functional metabolism images are SPECT and 18F-FDG. At the same time, we also selected eight representative fusion models as comparative experiments. In terms of objective quality evaluation, we select six evaluation metrics in five categories to evaluate our model.

Conclusions

The fusion image obtained by our model can retain the effective information in source images to the greatest extent. In terms of image fusion evaluation metrics, our model is superior to other comparison algorithms. In terms of time computational efficiency, our model also performs well. In terms of robustness, our model is very stable and can be generalized to multi-modal image fusion of other organs.

Surgical Simulation with Three-Dimensional Fusion Images in Patients with Arteriovenous Malformation

In arteriovenous malformation (AVM) surgery, vessel structures should be well evaluated with angiography. However, with conventional angiography, it is sometimes difficult to distinguish each feeder and its feeding territory in the nidus. In this study, we used two software systems to create three-dimensional (3D) fusion images using multiple imaging modalities and evaluated their clinical use. In the AVM patient, data were obtained from 3D rotational angiography, rotational venography, computed tomography (CT), and magnetic resonance imaging (MRI) and superimposed into 3D fusion images using imaging software (iPLAN and Avizo). Virtual surgical fields that were quite similar to the real ones were also created with these software programs. Compared with fusion images by iPLAN, those by Avizo have higher resolution and can demarcate not only each feeder but also its supplying territory in the nidus with different colors.In conclusion, 3D fusion images in AVM surgery are helpful for simulation, even though it takes time and requires special skill to create them.

Surgical Treatment of Intramedullary Hemangioblastomas: Current State of Problem (Review)

Intramedullary hemangioblastomas (HAB) refer to very rare highly vascularized vascular spinal cord tumors associated with various neurological disorders. Effective HAB therapy to a greater extent depends on diagnostic accuracy and the absence of intra- and postoperative complications.

The present study is a review of publications concerned with modern diagnostic and therapeutic techniques to control spinal HAB. The authors showed that perfusion computed tomography, computed tomographic angiography, and magnetic resonance angiography can be reasonably used for diagnosis and differentiation in a number of HAB due to their high vascularization. Preoperative embolization significantly reducing intraoperative bleeding risks is highly efficient. Some authors recommend this procedure in case of large lesions and high risks of intraoperative bleeding. The review also considered intraoperative imaging of a tumor and its feeding vessels using indocyanine green providing inspectability over the total tumor resection and clear imaging of tumor vascular architecture. The advantages and restrictions of the mentioned procedures were described.

Safe handling of veins in the pineal region-a mixed method study

Surgical experience in pineal surgery is largely confined to a few experienced surgeons and may be lost when they stop their practice. The objective of this study is to systematically preserve and analyze valuable practical knowledge of pineal region surgical venous anatomy. A survey was constructed to obtain experienced surgeons' perception of estimated risks and individual experience following occlusion of veins during pineal surgery. Data were qualitative and analyzed with a mixed methods approach. Of the 126 invited neurosurgeons, 40 submitted completed questionnaires. General agreement existed of which veins were associated with high and low risks following occlusion. The risk of death was estimated to be high with sacrifice of the vein of Galen (83%), both internal cerebral veins (69%) and the basal veins (58%). The risk of death was estimated to be lower with the sacrifice of both superior vermian veins (13%) and one internal occipital vein (10%). Importantly, a sub-group of experienced surgeons reported substantial risk of death and consequences with the sacrifice of cerebellar bridging veins (8-13%). Our findings provide a coherent picture of surgical risk with venous sacrifice, which can inform the surgical community of systematically gathered views from aggregated surgeries of a very large cohort of patients. Extensive presurgical radiological workup and anatomical studies seemed to correlate more cautious risk estimations. Our findings increase available knowledge of risks of venous complications.

Three-dimensional multimodality fusion imaging as an educational and planning tool for deep-seated meningiomas

INTRODUCTION

The utility of surgical simulation with three-dimensional multimodality fusion imaging (3D-MFI) has been demonstrated. However, its potential in deep-seated brain lesions remains unknown. The aim of this study was to investigate the impact of 3D-MFI in deep-seated meningioma operations.

MATERIAL AND METHODS

Fourteen patients with deeply located meningiomas were included in this study. We constructed 3D-MFIs by fusing high-resolution magnetic resonance (MR) and computed tomography (CT) images with a rotational digital subtraction angiogram (DSA) in all patients. The surgical procedure was simulated by 3D-MFI prior to operation. To assess the impact on neurosurgical education, the objective values of surgical simulation by 3D-MFIs/virtual reality (VR) video were evaluated. To validate the quality of 3D-MFIs, intraoperative findings were compared. The identification rate (IR) and positive predictive value (PPV) for the tumor feeding arteries and involved perforating arteries and veins were also assessed for quality assessment of 3D-MFI.

RESULTS

After surgical simulation by 3D-MFIs, near-total resection was achieved in 13 of 14 (92.9%) patients without neurological complications. 3D-MFIs significantly contributed to the understanding of surgical anatomy and optimal surgical view (p < .0001) and learning how to preserve critical vessels (p < .0001) and resect tumors safety and extensively (p < .0001) by neurosurgical residents/fellows. The IR of 3D-MFI for tumor-feeding arteries and perforating arteries and veins was 100% and 92.9%, respectively. The PPV of 3D-MFI for tumor-feeding arteries and perforating arteries and veins was 98.8% and 76.5%, respectively.

CONCLUSIONS

3D-MFI contributed to learn skull base meningioma surgery. Also, 3D-MFI provided high quality to identify critical anatomical structures within or adjacent to deep-seated meningiomas. Thus, 3D-MFI is promising educational and surgical planning tool for meningiomas in deep-seated regions.

The usefulness of indocyanine green during surgery for hypervascular posterior fossa tumors

BACKGROUND

Cerebral hemangioblastomas are benign tumors with abundant blood flow that occur mainly in the posterior fossa. Tumor removal en bloc is important in surgical treatment because of the risk of bleeding; however, it is actually rather difficult in practice. Therefore, we propose a surgical strategy for visualizing hypervascular tumors of the posterior fossa utilizing indocyanine green (ICG).

CASE DESCRIPTION

Case 1 involved a 48-year-old male with a history of von Hippel-Lindau (VHL) disease. Magnetic resonance imaging (MRI) revealed a solid tumor measuring 3.0 cm in diameter in the right cerebellopontine angle. We performed surgery because the tumor was pressing against the brainstem. Surgery was performed via the posterior subtemporal transtentorial approach in order to visualize the feeding artery and draining vein intraoperatively. The vessels were confirmed by ICG and the tumor was removed en bloc. Case 2 involved a 30-year-old woman. Signs of increased intracranial pressure were noted, and an MRI revealed a solid tumor 3.5 cm in diameter in the left cerebellar hemisphere. Surgery was performed via the midline suboccipital approach. Similarly, we confirmed the vessels using ICG and the tumor was removed en bloc.

CONCLUSIONS

For hypervascular tumors of the posterior fossa, preoperative image assessment is important. Furthermore, the use of ICG during surgery is advantageous for surgical strategies where the feeding arteries and draining veins exist superficially in the operative field and are therefore easier to remove en bloc.

Bone flap elevation for intracranial EEG monitoring: technical note

Intracranial electroencephalography (iEEG) provides invaluable information in determining seizure focus and spread due to its high spatial and temporal resolution, which are not afforded by noninvasive studies. Electrodes of various types (e.g., grid, strip, and depth electrodes) and configurations are often used for optimum coverage of suspected areas of seizure onset and propagation. Given the fixed intracranial volume and added mass effect from placement of cortical electrodes, brain edema and postoperative deficits can occur. The authors describe a simple, inexpensive, and highly effective technique of bone flap replacement using standard titanium plates to expand the intracranial volume and minimize risks of brain compression and intracranial hypertension. Rectangular titanium plates are bent and placed in a way that secures the bone flap in a slightly elevated position relative to the adjacent calvaria during iEEG monitoring. The authors evaluated the degree of bone flap elevation and amount of volume created using this technique in 3 iEEG cases. They then compared these results with the bone flap elevation and volume created using linear titanium plates, a method they had used previously. The use of rectangular plates produced on average 6.6 mm of bone flap elevation, compared with only 1.8 mm of bone flap elevation with the use of linear plates, resulting in a statistically significant 261% increase in bone flap elevation (p ≤ 0.001). The authors suggest that rectangular plates may provide stronger resistance to scalp tension after myocutaneous skin closure compared with the linear plates and that subsidence of the bone flap likely occurred with the use of linear plates. In summary, the described technique utilizing rectangular plates creates significantly increased bone flap elevation compared with a similar method using linear plates, and it may reduce the risk of neurological deficits related to intracranial electrode placement.