Border Zone Maybe Correlated with Radiation Necrosis After Radiosurgery in Metastatic Brain Tumor.

BACKGROUND: Radiation necrosis (RN) after stereotactic radiosurgery (SRS) in brain metastases has been extensively evaluated, and RN is correlated with various risk factors. However, no study comprehensively analyzed the correlation between RN and the border zones of the brain that are vulnerable to ischemia. We hypothesized that patients with tumors in the border zone are at high risk of RN. Hence, the current study aimed to assess the correlation between border zone lesions and RN, with consideration of other predetermined factors. METHODS: This retrospective study included 117 patients with 290 lesions who underwent Gamma Knife SRS. Radiological and clinical analyses were performed to identify factors possibly correlated with RN. Notably, the lesion location was classified into 2 groups (border zone and nonborder zone) based on the blood supply. RESULTS: In total, 22 (18.8%) patients with 22 (7.5%) lesions developed RN. Univariate analysis revealed a significant correlation between RN and external border zone lesions, second course of SRS administered at the same site of the previous SRS, prescribed dose, and tumor volume. Multivariate analysis showed that border zone lesions, second course of SRS at the same site of the previous SRS, and tumor volume were significantly correlated with RN. CONCLUSIONS: Patients with tumors in the border zone are at high risk of RN. The potential risks of RN can be attributed hypothetically to hypoperfusion. Hence, the association between RN and border zone lesions seems reasonable.

Venous ectasia preceding intra-tumoral hemorrhage in a case of gliosarcoma with transverse sinus involvement.

Although intratumoral hemorrhage is common in patients with malignant brain tumors, reports on its clinical course are scarce. This report presents a rare case of a patient with intratumoral hemorrhage with gliosarcoma invading the venus sinus. This invasion and a small draining vein were observed at diagnosis. Magnetic resonance imaging performed 1 week later showed new-onset venous ectasia, which caused intratumoral hemorrhage. This case provides insight into the mechanisms underlying intratumoral hemorrhage and highlights the emergence of new intratumoral vasculature as a potential warning sign for hemorrhage.

Unexpected shunt-dependent hydrocephalus after unruptured aneurysm surgery-a case report.

A chronic hydrocephalus after unruptured aneurysm surgery is an extremely rare condition. Its etiology and pathophysiology are also unclear. We report a case of chronic hydrocephalus in a patient who underwent permanent shunt placement after unruptured aneurysm clipping surgery. A 65-year-old man developed chronic hydrocephalus requiring shunt placement after clipping surgery of left anterior cerebral artery aneurysm and right middle cerebral artery aneurysm. This case shows that chronic hydrocephalus is a possible complication of unruptured aneurysm surgery, which can be resolved with an appropriate shunt operation.

Development of an Angiography Guide Indicator for Stereotactic Radiosurgery for High Precision.

BACKGROUND: Stereotactic radiosurgery (SRS) is effectively used for treating various cerebrovascular diseases, including arteriovenous malformations. As image-based surgery is the gold standard technique in SRS, the quality of stereotactic angiography images greatly influences the surgical approach for cerebrovascular diseases. Despite several studies in the relevant literature, research on auxiliary devices, including angiography indicators used for cerebrovascular disease surgeries, is limited. Thus, the development of angiographic indicators may provide meaningful data for stereotactic surgery. METHODS: A centerline was drawn, and a guideline was attached such that the "+" and "X" centers of the existing angiography guide indicator intersect. Further, a guideline wire connecting "+" and "X" was fixed using a tape. Based on the presence or absence of the guide indicator, angiography anterior-posterior (AP) and lateral (LAT) images were taken 10 times each, and statistical analysis was performed. RESULTS: The average and standard deviation of the conventional AP and LAT indicators were 10.22 ± 0.53 mm and 9.02 ± 0.33 mm, and those of the developed AP and LAT indicators were 10.3 ± 0.57 mm and 8.92 ± 0.23 mm, respectively. CONCLUSIONS: The results confirmed that the use of the lead indicator developed in this study provides higher accuracy and precision compared to that of the use of the conventional indicator. Furthermore, the developed guide indicator may provide meaningful information during SRS.

Frictional force analysis of stent retriever devices using a realistic vascular model: Pilot study.

Objective: To date, no vascular model to analyze frictional forces between stent retriever devices and vessel walls has been designed to be similar to the real human vasculature. We developed a novel in vitro intracranial cerebrovascular model and analyzed frictional forces of three stent retriever devices. Methods: A vascular mold was created based on digital subtraction angiography of a patient's cerebral vessels. The vascular model was constructed using polydimethylsiloxane (PDMS, Dow Corning, Inc.) as a silicone elastomer. The vascular model was coated on its inner surface with a lubricating layer to create a low coefficient of friction (~0.037) to closely approximate the intima. A pulsatile blood pump was used to produce blood flow inside the model to approximate real vascular conditions. The frictional forces of Trevo XP, Solitaire 2, and Eric 4 were analyzed for initial and maximal friction retrieval forces using this vascular model. The total pulling energy generated during the 3 cm movement was also obtained. Results: Results for initial retrieval force were as follows: Trevo, 0.09 ± 0.04 N; Solitaire, 0.25 ± 0.07 N; and Eric, 0.33 ± 0.21 N. Results for maximal retrieval force were as follows: Trevo, 0.36 ± 0.07 N; Solitaire, 0.54 ± 0.06 N; and Eric, 0.80 ± 0.13 N. Total pulling energy (N·cm) was 0.40 ± 0.10 in Trevo, 0.65 ± 0.10 in Solitaire, and 0.87 ± 0.14 in Eric, respectively. Conclusions: Using a realistic vascular model, different stent retriever devices were shown to have statistically different frictional forces. Future studies using a realistic vascular model are warranted to assess SRT devices.

Development of an Animal Stereotactic Device for Preclinical Research on Tumor Response After Stereotactic Radiosurgery.

BACKGROUND: In gamma knife radiosurgery, the tumor response to radiation is an important predictor of clinical treatment results. Since brain tumors have different characteristics and growth patterns, depending on the type, the tumors' response to radiation are also different. Compared with various other clinical treatments, there is a dearth of research on the development of gamma knife-magnetic resonance imaging (MRI) preclinical experimental equipment. Hence, the identification of preclinical equipment necessity for experimental animals will provide meaningful data for the provision of clinical assistance to humans. OBJECTIVES: A device for stereotactic radiosurgery capable of MRI in small animals was developed. The feasibility of creating a preplan by means of small animal images was then assessed. METHODS: A device for stereotaxic surgery of small animals using a 48-channel MRI coil was developed using a 3 dimensional printer. Rat brain-MRI images were obtained with a 3.0 T MRI scanner using a multi-channel coil. The acquired MRI images were transferred to a GammaPlan workstation to establish a preplan. RESULTS: To gamma rays to the targeted site on animals, a positioning device combined with a G-frame was mounted on a gamma knife. Planning of radiosurgery based on MRI images became possible with GammaPlan workstations. CONCLUSIONS: Preclinical experiments using small animals are possible with the use of stereotactic devices. In clinical treatment, preclinical experimental results will provide meaningful information.

Novel Animal Model of Spontaneous Cerebral Petechial Hemorrhage Using Focused Ultrasound in Rats.

Background and Objectives: Petechial cerebral hemorrhages can be caused by various factors, such as traumas, cerebral infarctions, and aging, and is related to the disruption of the blood-brain barrier or the cellular damage of blood vessels. However, there is no animal model that recapitulates cerebral petechial hemorrhages. Materials and Methods: Here, we implemented a petechial hemorrhage using a novel technology, i.e., microbubble-assisted focused ultrasound (MB + FUS). Results: This method increases the permeability of the blood-brain barrier by directly applying mechanical force to the vascular endothelial cells through cavitation of the microbubbles. Microbubble-enhanced cavitation has the advantage of controlling the degree and location of petechial hemorrhages. Conclusions: We thus generated a preclinical rat model using noninvasive focal MB + FUS. This method is histologically similar to actual petechial hemorrhages of the brain and allows the achievement of a physiologically resembling petechial hemorrhage. In the future, this method shall be considered as a useful animal model for studying the pathophysiology and treatment of petechial cerebral hemorrhages.

Effect of Cadherin-11 Expression on the Prognosis of a Newly Diagnosed Primary Glioblastoma.

BACKGROUND: Cadherin-11, a cell-to-cell adhesion molecule, is associated with higher tumor grade and decreased patient survival. The purpose of this study was to investigate the clinical significance of cadherin-11 expression in the progression and prognosis of a newly diagnosed primary glioblastoma (GBL). METHODS: Between 2007 and 2016, 52 out of 178 patients diagnosed with a GBL and satisfied the following criteria: 1) a new primary GBL, 2) gross-total resection, 3) immunohistochemically-available tissue, and 4) standardized adjuvant treatment. RESULTS: In terms of staining intensity, the low-intensity cadherin-11 group showed longer progression-free survival (PFS) than the high-intensity cadherin-11 group (median PFS, 12.0 months [95% CI, 11.1-12.9] vs. median PFS, 6.0 months [95% CI, 3.7-8.3]; p<0.001). The low-intensity cadherin-11 group revealed longer overall survival (OS) than the high-intensity cadherin-11 group (median OS, 20.0 months [95% CI, 11.8-16.6] vs. median OS, 15.0 months [95% CI, 11.8-18.2]; p=0.003). The staining intensity of cadherin-11 was a statistically significant factor in PFS and OS in terms of univariate and multivariate analyses (univariate analysis: p<0.001 and p=0.005; multivariate analysis: p<0.001 and p=0.005). CONCLUSION: Our clinical study demonstrates high cadherin-11 expression may be associated with poor PFS and OS for a newly diagnosed primary GBL.

Verification of Blood-Brain Barrier Disruption Based on the Clinical Validation Platform Using a Rat Model with Human Skull.

Methods to improve drug delivery efficiency through blood-brain barrier disruption (BBBD) based on microbubbles and focused ultrasound (FUS) are continuously being studied. However, most studies are being conducted in preclinical trial environments using small animals. The use of the human skull shows differences between the clinical and preclinical trials. BBBD results from preclinical trials are difficult to represent in clinical trials because various distortions of ultrasound by the human skull are excluded in the former. Therefore, in our study, a clinical validation platform based on a preclinical trial environment, using a human skull fragment and a rat model, was developed to induce BBBD under conditions similar to clinical trials. For this, a human skull fragment was inserted between the rat head and a 250 kHz FUS transducer, and optimal ultrasound parameters for the free field (without human skull fragment) and human skull (with human skull fragment) were derived by 300 mVpp and 700 mVpp, respectively. BBBD was analyzed according to each case using magnetic resonance images, Evans blue dye, cavitation, and histology. Although it was confirmed using magnetic resonance images and Evans blue dye that a BBB opening was induced in each case, multiple BBB openings were observed in the brain tissues. This phenomenon was analyzed by numerical simulation, and it was confirmed to be due to standing waves owing to the small skull size of the rat model. The stable cavitation doses (SCDh and SCDu) in the human skull decreased by 13.6- and 5.3-fold, respectively, compared to those in the free field. Additionally, the inertial cavitation dose in the human skull decreased by 1.05-fold compared to that of the free field. For the histological analysis, although some extravasated red blood cells were observed in each case, it was evaluated as recoverable based on our previous study results. Therefore, our proposed platform can help deduct optimal ultrasound parameters and BBBD results for clinical trials in the preclinical trials with small animals because it considers variables relevant to the human skull.

Bridging the intracranial pressure gap: a smooth transition strategy for slit ventricle syndrome.

Slit ventricle syndrome (SVS) is a well-known complication of long-standing shunts. Patients develop intermittent severe headache, vomiting with other symptoms of increased intra-cranial pressure. Brain computed tomography (CT) usually reveals slit-like ventricles with nearly obstructed proximal catheters. Treatment for SVS usually involves upgrading the shunt valve pressure setting. Currently, many patients carry programmable shunts and pressure setting can be adjusted noninvasively. However, when the programmable valve pressure setting is upgraded, some patients with SVS experience worsened symptoms. This is caused by the time gap between ICP increase and real ventricular expansion (and freeing proximal catheter) after shunt upgrading. Therefore, it is important to control a patient's symptoms during the transition period. We report our experience in controlling ICP in a patient with SVS using external ventricular drainage.

Transversus abdominis plane block for lumboperitoneal shunt surgery in idiopathic normal pressure hydrocephalus: a case report.

The transversus abdominis plane (TAP) block is an ideal pain control method used in surgeries that require abdominal wall incisions through the injection of an anesthetic solution into the plane between the internal oblique muscle and transversus abdominis muscle. Herein, we report an 83-year-old man who was diagnosed with idiopathic normal pressure hydrocephalus (iNPH) and underwent lumboperitoneal shunt surgery (LPS). The TAP block was performed before LPS, and the numerical rating scale for pain was 0 at day 1 after the surgery. The patient was discharged early at day 3 after surgery despite the patient being extremely old, as he reported quick relief from the postoperative abdominal pain. The TAP block can hence be considered for use before LPS in elderly patients with iNPH.

Clinical significance of vitamin D in idiopathic normal pressure hydrocephalus.

BACKGROUND: Although recent studies show vitamin D deficiency is associated with cognitive decline, urinary incontinence, and gait instability, there has been no study on the effect of vitamin D on idiopathic normal pressure hydrocephalus (iNPH) characterized by the classic symptom triad of cognitive decline, urinary incontinence, and gait instability. We investigated the clinical significance of vitamin D in patients with iNPH. METHODS: Between 2017 and 2020, 44 patients who underwent ventriculoperitoneal shunt surgery were divided into low (< 15 ng/mL) and high (≥ 15 ng/mL) vitamin D groups according to the concentration of 25(OH)D, an effective indicator of vitamin D status. They were respectively evaluated according to clinical and radiological findings. RESULTS: The low vitamin D group (n = 24) showed lower preoperative cognition compared to the high vitamin D group (n = 20) in terms of Korean-Mini Mental Status Examination (K-MMSE) and iNPH grading scale (iNPHGS) (K-MMSE: 20.5 ± 5.4 versus 24.0 ± 4.5, p = 0.041; iNPHGS cognitive score: 2 ± 0.9 versus 1 ± 0.6, p = 0.025). And the low vitamin D group showed pre- and postoperatively more severe urinary incontinence (preoperative iNPHGS urinary score: 1 ± 1.0 versus 0 ± 0.9, p = 0.012; postoperative iNPHGS urinary score:1 ± 1.0 versus 0 ± 0.9, p = 0.014). The score of narrow high-convexity sulci for the low vitamin D group was lower (low vitamin D group: 1 ± 0.7 versus high vitamin D group: 2 ± 0.4, p = 0.031). CONCLUSION: Lower concentration of vitamin D in iNPH may be related to lower preoperative cognition, pre- and postoperative urinary incontinence, and brain morphological change.

Clinical usefulness of deep learning-based automated segmentation in intracranial hemorrhage.

BACKGROUND: Doctors with various specializations and experience order brain computed tomography (CT) to rule out intracranial hemorrhage (ICH). Advanced artificial intelligence (AI) can discriminate subtypes of ICH with high accuracy. OBJECTIVE: The purpose of this study was to investigate the clinical usefulness of AI in ICH detection for doctors across a variety of specialties and backgrounds. METHODS: A total of 5702 patients' brain CTs were used to develop a cascaded deep-learning-based automated segmentation algorithm (CDLA). A total of 38 doctors were recruited for testing and categorized into nine groups. Diagnostic time and accuracy were evaluated for doctors with and without assistance from the CDLA. RESULTS: The CDLA in the validation set for differential diagnoses among a negative finding and five subtypes of ICH revealed an AUC of 0.966 (95% CI, 0.955-0.977). Specific doctor groups, such as interns, internal medicine, pediatrics, and emergency junior residents, showed significant improvement with assistance from the CDLA (p= 0.029). However, the CDLA did not show a reduction in the mean diagnostic time. CONCLUSIONS: Even though the CDLA may not reduce diagnostic time for ICH detection, unlike our expectation, it can play a role in improving diagnostic accuracy in specific doctor groups.

A novel self-seeding method for particle image velocimetry measurements of subsonic and supersonic flows.

A self-seeding particle method is proposed for particle image velocimetry measurements in closed cycles such as Organic Rankine Cycles. Condensed droplets of vapor are used as tracers in a closed cycle for both subsonic and supersonic regimes. A free jet of R245fa in the vapor phase is examined in a case study with two different nozzle pressure ratios of 5.1 and 2.1 to evaluate the tracer particles in both supersonic and subsonic conditions. A simple turbulent jet in subsonic conditions and an under-expanded jet are observed in high supersonic conditions. The flow structures of the under-expanded jet are captured using the proposed method, and vivid images of the Mach disk and shock cells are obtained. A series of Schlieren photography experiments are performed to validate the proposed method. The results show that the method can be a good candidate for tracer particles in the closed cycles where condensation of the working fluid is possible.

CT window trainable neural network for improving intracranial hemorrhage detection by combining multiple settings.

Window settings to rescale and contrast stretch raw data from radiographic images such as Computed Tomography (CT), X-ray and Magnetic Resonance images is a crucial step as data pre-processing to examine abnormalities and diagnose diseases. We propose a distant-supervised method for determining automatically the best window settings by attaching a window estimator module (WEM) to a deep convolutional neural network (DCNN)-based lesion classifier and training them in conjunction. Aside from predicting a flexible window setting for each raw image, we statistically identify the top four window settings by calculating the mean and standard deviations for the entire dataset. Images are scaled on each of the top settings estimated by WEM and following lesion classifiers are subsequently trained. We study the effects of only using the flexible window, the single fixed window as either a known default window used by radiologists or an estimated mean value, and two different approaches to combine results from the top window settings to improve the detection of intracranial hemorrhage (ICH) from brain CT images. Experimental results showed that using the top four window settings identified from the window estimator module and combining the results had the best performance.

Sinonasal Teratocarcinosarcoma, a Rare Tumor Involving Both the Nasal Cavity and the Cranial Cavity.

Sinonasal teratocarcinosarcoma (SNTCS), a very rare tumor, is known to be a heterogeneous with epithelial, mesenchymal, and neuroepithelial components and shows a very aggressive clinical course. Due to the heterogeneity of this tumor, it is often misdiagnosed. No definitive treatment modality has been reported because it is a very rare tumor. A 44-year-old man presented to a rhinologist with headache and nasal obstruction, and an intranasal tumor was found that invaded into the cranial cavity. He underwent combined surgery with a rhinologist and a neurosurgeon following cognitive decline that worsened after a transnasal biopsy. The patient was diagnosed with SNTCS and underwent radiotherapy. However, residual tumor was found during radiotherapy and additional chemotherapy was administered. Follow-up brain MRI revealed no remnant or recurrent lesion. SNTCS is a tumor that has not yet been well researched and should be further investigated for proper treatment.

Gamma Knife Radiosurgery Using Co-Registration with PET-CT and MRI for Recurrent Nasopharyngeal Carcinoma with Previous Radiotherapy : A Single Center 14-Year Experience.

OBJECTIVE: We retrospectively evaluated the efficacy of Gamma Knife radiosurgery (GKS) for recurrent nasopharyngeal carcinoma (NPC) in patients who previously underwent radiotherapy, and analyzed the treatment outcomes over 14 years. METHODS: Ten patients with recurrent NPC who had previously received radiotherapy underwent stereotactic radiosurgery using a Gamma Knife® (Elekta Inc, Atlanta, GA, USA) between 2005 and 2018. The median target volume was 8.2 cm3 (range, 1.7-17.8), and the median radiation dose to the target was 18 Gy (range, 12-30). The median follow-up period was 18 months (range, 6-76 months). Overall and local failure-free survival rates were determined using the Kaplan-Meier method. RESULTS: The NPCs recurred at the primary cancer site in seven patients (70%), as distant brain metastasis in two (20%), and as an extension into brain in one (10%). The recurrent tumors in seven of the 10 patients (70%) were found on the routine follow-up imaging studies. Two patients presented with headache and one with facial pain. Local failure after GKS occurred in five patients (50%) : two of whom died eight and 6 months after GKS, respectively. No adverse radiation effects were noted after GKS. The 1- and 3-year overall survival rates after GKS were 90% and 77%, respectively. The local failure-free survival rates at 6 months, 1 year, and 3 years after GKS were 80%, 48%, and 32%, respectively. The median interval from GKS to local failure was 8 months (range, 6-12). Univariate analysis revealed that using co-registration with positron emission tomography-computed tomography (PET-CT) and magnetic resonance imaging (MRI) was associated with a lower local failure rate of recurrent NPC (p=0.027). CONCLUSION: GKS is an acceptable salvage treatment option for patients with recurrent NPC who previously received radiation therapy. PET-CT and MRI co-registration for dose planning can help achieve local control of recurrent NPC.

A Case of Primary Central Nervous System Vasculitis That Worsened Despite Early Corticosteroid Therapy.

Primary central nervous system vasculitis (PCNSV) is rare, and the diagnosis is difficult to make because of its variable radiologic expressions. Early corticosteroid therapy often is effective. Herein we report the case of a 56-year-old man who had a well-enhanced cystic mass with severe edema in the right frontal lobe, which was initially felt to be a malignancy. Histologic examination of tissue removed at craniotomy revealed that it was a PCNSV. Despite early administration of corticosteroids, a new lesion developed within 3 days. The lesions responded to treatment with cyclophosphamide and corticosteroid.

Progressively enlarging childhood chronic subdural hematoma surgically treated 26 years after diagnosis.

Pediatric chronic subdural hematoma (CSDH) is a relatively common disorder. Treatment often requires burr hole drainage or subduroperitoneal shunt placement; some patients are managed conservatively. However, the long-term outcome of untreated pediatric CSDH is unknown. The authors report a case of a huge, progressively enlarging subdural granuloma that was surgically treated 26 years after the initial diagnosis of CSDH. This 30-year-old male patient presented with worsening intermittent atonic seizure-like movements, which had been noted since he was 4 years old. At that time, the patient was diagnosed with CSDH at an outside hospital, but an operation was refused by the parents. Magnetic resonance imaging (MRI) performed at 23 years of age showed a huge subdural mass on the right frontoparietal region and a smaller mass on the left side with a significant midline shift. Upon presentation at the age of 30, MRI revealed worsening of the right subdural mass and midline shift. Subsequently, the patient underwent craniotomy and subtotal removal of the mass and capsule. The volume of the content was approximately 430 cc. Untreated pediatric CSDH can grow progressively, even over several decades. Patients with CSDH, especially those managed conservatively, should be closely monitored for worsening symptoms over a long-term follow-up period.