Parikh, Parth

Background Intracranial occlusions in embolic stroke of undetermined source are histopathologically similar to cardiac sources of embolism. Whether patients with embolic stroke of undetermined source and intracranial occlusion benefit from anticoagulation is unknown. Methods A multicenter retrospective cohort of adults with cryptogenic stroke was queried for patients with proximal or medium/distal vessel occlusion. The primary outcome was recurrent ischemic stroke, which was assessed in unadjusted and adjusted Cox proportional hazards models and repeated following 1:1 propensity score matching and biweight kernel density matching. Results Of the 2328 patients who were followed over a median of 1.31 years (interquartile range, 0.34–2.85), 999 (42.6%) had an intracranial occlusion. When compared with patients without an intracranial occlusion, those with an occlusion had fewer atherosclerotic vascular risk factors, more severe symptoms, and less severe cerebral microvascular disease. The rate of recurrent stroke was similar between patients with versus without an intracranial occlusion (6.8%/year [95% CI, 5.7–8.2] versus 7.0%/year [95% CI 6.0–8.1]; adjusted hazard ratio [HR], 1.09 [95% CI, 0.77–1.55]). There was no association between occlusion and recurrent stroke in the adjusted propensity score matching (HR, 1.01 [95% CI, 0.64–1.59]) or kernel density models (HR, 0.95 [95% CI, 0.62–1.45]). There was no interaction between occlusion and treatment with anticoagulation, sex, age, or high‐risk sources of embolism for the primary outcome in the unmatched and matched analyses. Conclusions Intracranial occlusion in patients with embolic stroke of undetermined source is not associated with a greater risk of recurrence when compared with patients without an intracranial occlusion. There was no difference in rate of recurrent stroke with anticoagulation when stratified by presence or absence of occlusion.

Objective To determine the frequency and accuracy of diffusion restriction (DR) of the retina and/or optic nerve (ON) detection on standard brain magnetic resonance diffusion-weighted imaging (DWI-MRI) in patients presenting with acute non-arteritic central retinal artery occlusion (CRAO). Methods This is a retrospective case-control study that includes all consecutive patients presenting to our tertiary academic center from 2013-2021 with acute non-arteritic CRAO (cases) or acute ischemic stroke syndrome (controls, age and gender-matched) that had brain MRI performed within 14 days from symptom onset. Two neurology residents (junior and senior), a vascular neurologist, and two neuroradiologists, blinded to the site of CRAO, independently reviewed the brain MRIs to assess for the presence of retina and ON DR. The consensus agreement between the two neuroradiologists was used to perform sensitivity and specificity analyses and calculate inter-rater reliability (prevalence-adjusted bias-adjusted kappa coefficient). Results A total of 128 patients with acute non-arteritic CRAO (mean (SD) age 69 (14) years; 50% female; median time from CRAO to DW-MRI 2 days (IQR 1-5)) and 128 age and gender-matched controls with acute cerebral ischemia were included. After the neuroradiologist consensus, DR was correctly identified in the retina or ON in 51/128 (39.8%) CRAO cases, retina alone 27.3%, ON alone 24.2%, and both retina and ON 11.7%, with almost perfect neuroradiologists’ inter-rater reliability for retina (K = 0.91) and ON (K = 0.83). Among controls, the retina DR was identified in 1/128 (0.8%) and ON DR in 5/128 (3.9%). The sensitivity, specificity, positive predictive value, and negative predictive value were 28.1%, 99.2%, 97.3%, and 58.0% for retina DR, and 27.3%, 96.1%, 87.5%, and 56.9% for ON DR. Conclusions Though experienced neuroradiologists identified retina and ON DR with excellent inter-rater reliability, these are infrequent findings in real world CRAO practice, with excellent specificity but limited sensitivity. Prospective studies with larger cohort of patients, optimization of standardized orbit DWI-MRI protocols are needed to facilitate a more accurate and reliable identification of retina and ON DR in acute CRAO.

Objective: To assess whether diffusion restriction (DR) of the retina and optic nerve (ON) can be accurately and reliably identified on standard stroke protocol brain magnetic resonance diffusion-weighted imaging (DWI-MRI) in patients presenting with acute non-arteritic central retinal artery occlusion (CRAO). Background: Retinal DR (RDR) and ONDR in patients with acute non-arteritic CRAO have been described with various diagnostic accuracies and often identified by experienced neuroradiologists with fair inter-rater agreement. Methods: This retrospective case-control study included patients that presented to our academic center from 2013-2021 with acute non-arteritic CRAO or acute cerebral ischemia (controls, age and gender-matched) and had brain MRI performed within 14 days from symptom onset. Two neuroradiologists, blinded to the site of CRAO and diagnosis, independently reviewed MRI of CRAO cases and controls to assess for the presence of RDR and ONDR. Their inter-rater agreement was calculated (prevalence and bias- adjusted kappa coefficient) and their final consensus was used to perform sensitivity and specificity analyses. Results: We included 128 patients with CRAO (mean age 69 years; 50% males; median time from CRAO to MRI 2 days (IQR 1-5)) and 128 matched controls with acute cerebral ischemia (mean age 68 years; 51% males). After neuroradiologists’ consensus, DR was correctly identified in the retina or ON in 51/128 (39.8%), retina alone 35/128 (27.3%), ON alone 31/128 (24.2%), both retina and ON 15/128 (11.7%), with excellent inter-rater agreement for retina (K=0.91) and ON (K=0.83). There were no cases of RDR or ONDR in the control group. After neuroradiologists’ consensus, sensitivity, specificity, PPV and NPV were 28.1%, 100%, 100%, and 58.2% for RDR and 27.3%, 100%, 100%, and 57.9% for ONDR. Conclusion: Though RDR and ONDR can be identified with excellent interrater reliability, they are infrequent findings and their role in diagnosing acute CRAO is unclear. Observational prospective studies with large cohort of patients, optimization of dedicated and standardized orbit DWI-MRI protocols, and education of neurology and neuroradiology providers are needed to facilitate more accurate identification of RDR and ONDR in hyperacute CRAO.

In a period when the budding field of neurosurgery was believed to have little promise, Dr Alfred Washington Adson founded and led the first neurosurgical department at Mayo Clinic. He was not without reservations—surgical intervention for neurological conditions was rarely pursued because of poor outcomes and high complication rates, and Dr Adson acknowledged his early concerns about the future of neurosurgery in his memoirs. However, his education, mentorship, his training, and his first neurosurgical cases helped to shape the impact he ultimately had on the field and his legacy as a neurosurgeon. Dr Adson trained with several renowned Mayo general surgeons, notably his mentor Dr Emil Beckman, whose desire for operative precision shaped Dr Adson's drive to develop his own skills as a surgeon. Two years into his residency, he became the youngest staff surgeon and was tasked with managing the neurosurgical cases at Mayo. The five neurosurgical cases overseen by Dr Adson in the next year illuminated the opportunity for neurosurgery to drastically improve the lives of patients. Dr Adson, given the option of continuing as either a general surgeon or a neurosurgeon, ultimately chose to pursue neurosurgery. This article seeks to provide a historical perspective on the neurosurgeon Dr Alfred Washington Adson using primary and secondary accounts from the Mayo archives, highlighting his contributions to the early understanding of intracranial pathology and how his early experiences as a trainee developed into a personal passion for self-improvement, education, and advocacy for health care in America.

Abstract Background Stereotactic radiosurgical rhizolysis of the trigeminal nerve is an established modality increasingly employed to alleviate the symptoms of refractory trigeminal neuralgia. This study analyzes the academic impact of the top 100 cited articles on the radiosurgical management of trigeminal neuralgia. Methods The Scopus database was searched for articles containing “radiosurgery” and one or more of “trigeminal neuralgia,” “trigeminus neuralgia,” and “tic douloureux.” The top 100 articles written in English were arranged in descending order by citation count. Documents were evaluated for authors, publication year, journal and impact factor, total citations, nationality, study type, radiosurgical modality, and the affiliated institution. Quantitative and qualitative analyses were performed on the data. Results The most cited articles were published between 1971 and 2019. The average citation per year was 4.3. The most targeted anatomic area was the “root entry zone” or proximal portion of the cisternal segment of the trigeminal nerve. The most utilized modality was Gamma Knife radiosurgery. The country with the highest number of publications was the United States. Thirty-six percent of the articles were published in the Journal of Neurosurgery. Lunsford, Kondziolka, Flickinger, and Régis, respectively, were the most frequently listed co-authors. The most prolific institute was the University of Pittsburgh Medical Center. Conclusion Stereotactic radiosurgery is an important modality in the management of medically or surgically refractory trigeminal neuralgia. This analysis assesses its contributions over the past five decades to identify trends in treatment practices for neurosurgeons and to highlight areas where further study is needed.

Introduction: Permanent perioperative vision loss is caused by ischemic optic neuropathy (ION) or central retinal artery occlusion (CRAO). Whereas diffusion restriction of the optic nerve (ON) on brain magnetic resonance imaging has been previously reported in perioperative posterior ION (PION), there are no reports of ON diffusion restriction in patients diagnosed with acute perioperative CRAO. We present a case of perioperative CRAO to highlight this neuroimaging finding for neuroradiologists and neurologists. Case Report: A 71-year-old male without vascular risk factors underwent maxillary bilateral antrostomy and septoplasty for chronic sinusitis. Twenty to thirty minutes upon awakening, he complained of painless left eye vision loss. Ophthalmoscopic examination showed retinal whitening, segmented arterioles, and hyperemic disc. Brain MR-diffusion weighted imaging/apparent diffusion coefficient revealed ON diffusion restriction in the proximal segment. Despite attempted reperfusion, left eye remained with no light perception at 6 months. Patients undergoing nonocular surgeries who develop perioperative vision loss related to PION may exhibit ON diffusion restriction but usually have normal ophthalmoscopic findings. CRAO shows retinal whitening, edema, segmentation of arterioles, and cherry red spot on ophthalmoscopy. A recent study reported that ON diffusion restriction in nonperioperative CRAO cases has a sensitivity and specificity of 55% and 70% to 100%. Here, PION was initially considered based on imaging. However, given the neuro-ophthalmic findings, a proximal embolus in the central retinal artery, obstructing its entrance into the proximal ON was deemed more likely. Conclusion: We highlight that proximal ON diffusion restriction on brain magnetic resonance imaging can be diagnostic of proximal thromboembolic CRAO. Future studies should evaluate the diagnostic utility and accuracy of MR-diffusion weighted imaging/apparent diffusion coefficient in perioperative visual loss.