Fully automated delineation of the optic radiation for surgical planning using clinically feasible sequences

[EN] Quadrantanopia caused by inadvertent severing of Meyer's Loop of the optic radiation is a well-recognised complication of temporal lobectomy for conditions such as epilepsy. Dissection studies indicate that the anterior extent of Meyer's Loop varies considerably between individuals. Quantifying this for individual patients is thus an important step to improve the safety profile of temporal lobectomies. Previous attempts to delineate Meyer's Loop using diffusion MRI tractography have had difficulty estimating its full anterior extent, required manual ROI placement, and/or relied on advanced diffusion sequences that cannot be acquired routinely in most clinics. Here we present CONSULT: a pipeline that can delineate the optic radiation from raw DICOM data in a completely automated way via a combination of robust pre-processing, segmentation, and alignment stages, plus simple improvements that bolster the efficiency and reliability of standard tractography. We tested CONSULT on 696 scans of predominantly healthy participants (539 unique brains), including both advanced acquisitions and simpler acquisitions that could be acquired in clinically acceptable timeframes. Delineations completed without error in 99.4% of the scans. The distance between Meyer's Loop and the temporal pole closely matched both averages and ranges reported in dissection studies for all tested sequences. Median scan-rescan error of this distance was 1¿mm. When tested on two participants with considerable pathology, delineations were successful and realistic. Through this, we demonstrate not only how to identify Meyer's Loop with clinically feasible sequences, but also that this can be achieved without fundamental changes to tractography algorithms or complex post-processing methods.Advance Queensland, Grant/Award Number: R-09964-01; Fundacion Merck Salud; Proyecto Societat Catalana Neurologia; Ministerio de Economia, Industria y Competitividad of Spain, Grant/Award Number: DPI2017-87743-R; Red Espanola de Esclerosis Multiple, Grant/Award Numbers: RD12/0032/0002, RD12/0060/01-02, RD16/0015/0002, RD16/0015/0003; Spanish Government; Instituto de Salud Carlos III, Grant/Award Numbers: FIS 2015 PI15/00061, FIS 2015 - PI15/00587, FIS 2018 - PI18/01030Reid, LB.; Martínez-Heras, E.; Manjón Herrera, JV.; Jeffree, RL.; Alexander, H.; Trinder, J.; Solana, E.... (2021). Fully automated delineation of the optic radiation for surgical planning using clinically feasible sequences. Human Brain Mapping. 42(18):5911-5926. https://doi.org/10.1002/hbm.25658S59115926421

Postnatal development of arteriovenous malformations

Background: Arteriovenous malformations (AVMs) are commonly thought to be congenital malformations; however, patients usually present in adolescence or adulthood. This study was carried out to better understand the development of AVMs between birth and presentation. Methods: A retrospective review was performed of the medical records of all patients under 25 presenting to a single institution with an AVM or spontaneous intracerebral hemorrhage from 2000 to 2007. Results: Out of a total of 34 cases, 3 children were identified with delayed de novo appearance of an AVM after an intracerebral hemorrhage and normal initial angiography. The clinical and angiographic features are presented for these 3 patients and for an additional patient with AVM recurrence after complete surgical excision. Conclusions: In the light of these cases and a review of the literature, we suggest a hypothesis that AVMs develop postnatally, undergoing a period of growth in childhood or early adulthood, and that they may become symptomatic from the time of their earliest development. The trigger to growth may be shear stress stimulating growth factor expression by endothelial cells lining an arteriovenous fistula. Alternative stimuli, such as venous hypertension, cannot be ruled out. Copyrigh

Aminolevulinic acid (ALA)-protoporphyrin IX fluorescence guided tumour resection. Part 1: Clinical, radiological and pathological studies

The intraoperative identification and resection of glioma is a significant and important challenge in neurosurgery. Complete resection of the enhancing tumour increases the median survival time in glioblastoma compared to partial glioma resection; however, it is achieved in fewer than half of eligible patients when conventional tumour identification methods are used. Increasing the incidence of complete resection, without causing excess morbidity, requires new methods to accurately identify neoplastic tissue intraoperatively, such as use of the drug 5-amino-levulinic acid (ALA). After ALA ingestion, the fluorescent molecule protoporphyrin IX (PpIX) accumulates in high grade glioma, allowing the neurosurgeon to more easily detect and accurately resect tumour. The utility of ALA has been demonstrated in a large, multicentre phase III randomised control trial of 243 patients with high grade glioma. ALA use led to a significant increase in the incidence of complete resection (65% compared to 36%), improved progression-free survival at 6 months (41% compared to 21%), fewer reinterventions, and delayed onset of neurological deterioration. This review provides a broad assessment of ALA-PpIX fluorescence-guided resection, with Part 1 focusing on its clinical efficacy, and correlations with imaging and histology. The theoretical, biochemical and practical aspects of ALA use are reviewed in Part 2

Ten tips for teaching in the theatre tearoom: shifting the focus from teaching to learning

Educational encounters between surgeons and trainees are often brief, spontaneous, opportunistic events. In spite of their vast teaching experience, very few surgeons have had educational training that enables them to optimise such opportunities. This article reviews the literature on medical education and adult learning, and makes practical suggestions about how surgeons can best help trainees to learn. The most important ideas, such as creating a supportive learning environment, actively engaging the learner, and providing constructive feedback, are relevant to any teaching and learning, but are particularly applicable to informal, on-the-job educational encounters such as teaching in the theatre tearoom

The controversy over vertebroplasty: an analysis of the debate and proposals for a way forward

This paper examines the ongoing and often heated debate about the merits or otherwise of percutaneous vertebroplasty as a treatment for painful osteoporotic vertebral fractures. In spite of the proliferation of research on this topic there is no agreement over its indications, safety or efficacy. We discuss the ethical issues which arise when new medical interventions such as vertebroplasty are introduced and make suggestions of relevance not just to the case of vertebroplasty, but to the introduction of innovative procedures generally

Current strategies in the surgical management of cerebral metastases: an evidence-based review

Metastatic tumours are the most common form of cerebral neoplasm, occurring in up to 40% of patients with systemic cancer. Although the presence of metastatic disease portends limited survival, aggressive management of cerebral metastases is vital to preventing death from neurological causes and prolonging functional independence. Due to advancement in neurosurgical techniques and the advent of stereotactic radiosurgery as a non-operative alternative, current decision making for selecting the appropriate local treatment often results in clinical equipoise. In addition, the traditional blanket application of whole brain radiation has come under scrutiny as new evidence regarding the deleterious neurocognitive effects of ionizing radiation emerges. The completion of a series of randomized studies comparing the efficacy of surgery, radiosurgery, whole brain radiotherapy and various combined approaches for cerebral metastases in recent years has shed important light on addressing some of these issues. The focus of this review is to summarize the key findings and outline a practical approach for the management of cerebral metastases

An Unusual myopathy : speckled muscle fibers due to enlarged mitochondria

We report a 52-year-old woman who presented with a 6-month history of proximal muscle weakness, elevated serum creatine kinase, and myopathic pattern on electromyography (EMG). Histology of the muscle shows a speckled pattern due to clustering of enlarged mitochondria. The pathology resembles that of selenium deficiency. The patient was found to have borderline low serum selenium and also low vitamin D and thyroid-stimulating hormone. The cause of this unusual myopathy is probably multifactorial. This case is important because the unusual pathological picture represents a potentially treatable myopathy. In addition, we hope that publication of the complex clinical and biochemical abnormalities of this case, in conjunction with other case reports, may facilitate future elucidation of muscle mitochondrial function and dysfunction. Muscle Nerve, 2007 Most muscle diseases produce one of a limited range of stereotypic pathological responses in the muscle fibers. We report a case of myopathy with a clinical picture similar to polymyositis but with distinct and unusual features on light and electron microscopy. The histopathological features are similar to a previously reported patient with selenium deficiency after long-term total parenteral nutrition. Although the present patient did have slightly reduced serum selenium this is unlikely to have been the sole cause of the myopathy. The complex and multiple influences on selenium metabolism and mitochondrial pathology are discussed with particular reference to dietary and endocrine factors.5 page(s

Cerebral cryptococcoma mimicking glioblastoma

Cryptococcus neoformans and C. gattii cause invasive fungal disease, with meningitis being the most common manifestation of central nervous system (CNS) disease. Encapsulated cryptococcomas occur rarely, predominantly in immunocompetent hosts, usually related to C. gattii. Our patient was an immunocompetent man who presented with headache and a large cystic CNS lesion thought to be glioblastoma. Biopsy of a concomitant lung lesion confirmed cryptococcoma and empiric antifungal therapy was started for presumed CNS cryptococcoma. Antifungal therapy failed to shrink the CNS lesion, and surgical excision confirmed C. gattii CNS cryptococcoma. Following surgery he had complete resolution of symptoms. This case highlights that cryptococcoma cannot be distinguished from tumour on clinical or imaging findings. A combined medical and surgical approach is optimal for the management of large or surgically accessible cryptococcomas, as antifungal therapy alone is unlikely to penetrate large lesions sufficiently to lead to a cure