ASL Perfusion Lightbulb Sign: An Imaging Biomarker of Pediatric Posterior Fossa Hemangioblastoma.

BACKGROUND AND PURPOSE: Hemangioblastoma is a rare vascular tumor that occurs within the central nervous system in children. Differentiating hemangioblastoma from other posterior fossa tumors can be challenging on imaging, and preoperative diagnosis can change the neurosurgical approach. We hypothesize that a 'lightbulb sign' on the ASL sequence (diffuse homogenous intense hyperperfusion within the solid component of the tumor) will provide additional imaging finding to differentiate hemangioblastoma from other posterior fossa tumors. MATERIALS AND METHODS: In this retrospective comparative observational study, we only included pathology-proven cases of hemangioblastoma, while the control group consisted of other randomly selected pathology-proven posterior fossa tumors from January 2022 to January 2024. Two blinded neuroradiologists analyzed all applicable MRI sequences, including ASL sequence if available. ASL was analyzed for the 'lightbulb sign'. Disagreements between the radiologists were resolved by a third pediatric neuroradiologist. Chi-square and Fisher's exact test were used to analyze the data. RESULTS: 95 patients were enrolled in the study; 57 (60%) were male. The median age at diagnosis was 8 years old (IQR: 3-14). Out of the enrolled patients, 8 had hemangioblastoma, and 87 had other posterior fossa tumors, including medulloblastoma (n=31), pilocytic astrocytoma (n=23), posterior fossa ependymoma type A (n=16), and other tumors (n=17). The comparison of hemangioblastoma vs non-hemangioblastoma showed that peripheral edema (p=0.02) and T2 flow void (p=0.02) favors hemangioblastoma, whereas reduced diffusion (low ADC) (p=0.002) and ventricular system extension (p=0.001) favors nonhemangioblastoma tumors.Forty-two cases also had ASL perfusion sequences. While high perfusion favors hemangioblastoma (p=0.03), the lightbulb sign shows a complete distinction since all the ASL series of hemangioblastoma cases (n=4) showed the lightbulb sign, whereas none of the nonhemangioblastoma cases (n=38) showed the sign (p<0.001). CONCLUSIONS: Lightbulb-like intense and homogenous hyperperfusion patterns on ASL are helpful in diagnosing posterior fossa hemangioblastoma in children.ABBREVIATIONS ASL = Arterial spin labelling; pASL = Pulsed arterial spin labelling; pCASL = Pseudocontinuous arterial spin labelling; DCE = Dynamic contrast-enhanced; DSC = Dynamic susceptibility contrast; VHL = Von Hippel Lindau.

The Brain Tumor Segmentation (BraTS) Challenge 2023: Focus on Pediatrics (CBTN-CONNECT-DIPGR-ASNR-MICCAI BraTS-PEDs).

Pediatric tumors of the central nervous system are the most common cause of cancer-related death in children. The five-year survival rate for high-grade gliomas in children is less than 20%. Due to their rarity, the diagnosis of these entities is often delayed, their treatment is mainly based on historic treatment concepts, and clinical trials require multi-institutional collaborations. The MICCAI Brain Tumor Segmentation (BraTS) Challenge is a landmark community benchmark event with a successful history of 12 years of resource creation for the segmentation and analysis of adult glioma. Here we present the CBTN-CONNECT-DIPGR-ASNR-MICCAI BraTS-PEDs 2023 challenge, which represents the first BraTS challenge focused on pediatric brain tumors with data acquired across multiple international consortia dedicated to pediatric neuro-oncology and clinical trials. The BraTS-PEDs 2023 challenge focuses on benchmarking the development of volumentric segmentation algorithms for pediatric brain glioma through standardized quantitative performance evaluation metrics utilized across the BraTS 2023 cluster of challenges. Models gaining knowledge from the BraTS-PEDs multi-parametric structural MRI (mpMRI) training data will be evaluated on separate validation and unseen test mpMRI dataof high-grade pediatric glioma. The CBTN-CONNECT-DIPGR-ASNR-MICCAI BraTS-PEDs 2023 challenge brings together clinicians and AI/imaging scientists to lead to faster development of automated segmentation techniques that could benefit clinical trials, and ultimately the care of children with brain tumors.

Spontaneous Intrahepatic Portal Venous Shunt: Presentation and Endovascular Treatment.

Spontaneous intrahepatic portal venous shunts are rare with only few case reports published. Treatments using various endovascular techniques have been described, although no single technique has been shown to be preferred. We present a patient who was referred for treatment of a spontaneous portal venous shunt and describe our treatment approach and present a review on previously reported cases.

Drug eluting stents versus bare metal stents for the treatment of extracranial vertebral artery disease: a meta-analysis.

BACKGROUND: While a growing number of reports offer evidence for the potential of drug eluting stents (DES) in treating atherosclerotic stenosis of the extracranial vertebral artery, their efficacy when compared with bare metal stents (BMS) is uncertain due to the lack of a large prospective randomized trial. METHODS: A search strategy using the terms 'stents', 'drug-eluting stents', 'atherosclerosis', 'vertebral artery', and 'vertebrobasilar insufficiency' was employed through Medline. Five studies met the criteria for a comparative meta-analysis. The technical/clinical success, periprocedural complications, target vessel revascularization (TVR), rates of restenosis, recurrent symptoms, and overall survival were compared. RESULTS: There was no significant difference in the technical success (OR=1.528, p=0.622), clinical success (OR=1.917, p=0.274), and periprocedural complications (OR=0.741, p=0.614) between the two groups. An OR of 0.388 for no restenosis in the BMS to DES arms (p=0.001) indicated a significantly higher restenosis rate in the BMS group relative to the DES group (33.57% vs 15.49%). When compared with the DES group, the BMS group had a significantly higher rate of recurrent symptoms (2.76% vs 11.26%; OR=3.319, p=0.011) and TVR (4.83% vs 19.21%; OR=4.099, p=0.001). CONCLUSIONS: A significantly lower rate of restenosis, recurrent symptoms, and TVR was noted in the DES group compared with the BMS group.

A novel perfusion-based method for cochlear implant electrode insertion.

A cochlear implant (CI) restores partial hearing to profoundly deaf individuals. CI electrodes are inserted manually in the cochlea and surgeons rely on tactile feedback from the implant to determine when to stop the insertion. This manual insertion method results in a large degree of variability in surgical outcomes and intra-cochlear trauma. Additionally, implants often span only the basal turn. In the present study we report on the development of a new method to assist CI electrode insertion. The design objectives are (1) an automated and standardized insertion technique across patients with (2) more apical insertion than is possible by the contemporary methods, while (3) minimizing insertion trauma. The method relies on a viscous fluid flow through the cochlea to carry the electrode array with it. A small cochleostomy (∼100-150 um in diameter) is made in scala vestibuli (SV) and the round window (RW) membrane is opened. A flow of diluted Sodium Hyaluronate (also known as Hyaluronic Acid, (HA)) is set up from the RW to the SV opening using a perfusion pump that sets up a unidirectional flow. Once the flow is established an implant is dropped into the ongoing flow. Here we present a proof-of-concept study where we used this technique to insert silicone implants all the way to the cochlear apex in rats and gerbils. In light-microscopic histology, the implantation occurred without cochlear trauma. To further assess the ototoxicity of the HA perfusion, we measured compound action potential (CAP) thresholds following the perfusion of HA, and found that the CAP thresholds were substantially elevated. Thus, at this point the method is promising, and requires further development to become clinically viable.