Insights from the IronTract challenge: Optimal methods for mapping brain pathways from multi-shell diffusion MRI.

Limitations in the accuracy of brain pathways reconstructed by diffusion MRI (dMRI) tractography have received considerable attention. While the technical advances spearheaded by the Human Connectome Project (HCP) led to significant improvements in dMRI data quality, it remains unclear how these data should be analyzed to maximize tractography accuracy. Over a period of two years, we have engaged the dMRI community in the IronTract Challenge, which aims to answer this question by leveraging a unique dataset. Macaque brains that have received both tracer injections and ex vivo dMRI at high spatial and angular resolution allow a comprehensive, quantitative assessment of tractography accuracy on state-of-the-art dMRI acquisition schemes. We find that, when analysis methods are carefully optimized, the HCP scheme can achieve similar accuracy as a more time-consuming, Cartesian-grid scheme. Importantly, we show that simple pre- and post-processing strategies can improve the accuracy and robustness of many tractography methods. Finally, we find that fiber configurations that go beyond crossing (e.g., fanning, branching) are the most challenging for tractography. The IronTract Challenge remains open and we hope that it can serve as a valuable validation tool for both users and developers of dMRI analysis methods.

Associations of Disease-Modifying Therapies With COVID-19 Severity in Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: People with multiple sclerosis (MS) are a vulnerable group for severe coronavirus disease 2019 (COVID-19), particularly those taking immunosuppressive disease-modifying therapies (DMTs). We examined the characteristics of COVID-19 severity in an international sample of people with MS. METHODS: Data from 12 data sources in 28 countries were aggregated (sources could include patients from 1-12 countries). Demographic (age, sex), clinical (MS phenotype, disability), and DMT (untreated, alemtuzumab, cladribine, dimethyl fumarate, glatiramer acetate, interferon, natalizumab, ocrelizumab, rituximab, siponimod, other DMTs) covariates were queried, along with COVID-19 severity outcomes, hospitalization, intensive care unit (ICU) admission, need for artificial ventilation, and death. Characteristics of outcomes were assessed in patients with suspected/confirmed COVID-19 using multilevel mixed-effects logistic regression adjusted for age, sex, MS phenotype, and Expanded Disability Status Scale (EDSS) score. RESULTS: Six hundred fifty-seven (28.1%) with suspected and 1,683 (61.9%) with confirmed COVID-19 were analyzed. Among suspected plus confirmed and confirmed-only COVID-19, 20.9% and 26.9% were hospitalized, 5.4% and 7.2% were admitted to ICU, 4.1% and 5.4% required artificial ventilation, and 3.2% and 3.9% died. Older age, progressive MS phenotype, and higher disability were associated with worse COVID-19 outcomes. Compared to dimethyl fumarate, ocrelizumab and rituximab were associated with hospitalization (adjusted odds ratio [aOR] 1.56, 95% confidence interval [CI] 1.01-2.41; aOR 2.43, 95% CI 1.48-4.02) and ICU admission (aOR 2.30, 95% CI 0.98-5.39; aOR 3.93, 95% CI 1.56-9.89), although only rituximab was associated with higher risk of artificial ventilation (aOR 4.00, 95% CI 1.54-10.39). Compared to pooled other DMTs, ocrelizumab and rituximab were associated with hospitalization (aOR 1.75, 95% CI 1.29-2.38; aOR 2.76, 95% CI 1.87-4.07) and ICU admission (aOR 2.55, 95% CI 1.49-4.36; aOR 4.32, 95% CI 2.27-8.23), but only rituximab was associated with artificial ventilation (aOR 6.15, 95% CI 3.09-12.27). Compared to natalizumab, ocrelizumab and rituximab were associated with hospitalization (aOR 1.86, 95% CI 1.13-3.07; aOR 2.88, 95% CI 1.68-4.92) and ICU admission (aOR 2.13, 95% CI 0.85-5.35; aOR 3.23, 95% CI 1.17-8.91), but only rituximab was associated with ventilation (aOR 5.52, 95% CI 1.71-17.84). Associations persisted on restriction to confirmed COVID-19 cases. No associations were observed between DMTs and death. Stratification by age, MS phenotype, and EDSS score found no indications that DMT associations with COVID-19 severity reflected differential DMT allocation by underlying COVID-19 severity. DISCUSSION: Using the largest cohort of people with MS and COVID-19 available, we demonstrated consistent associations of rituximab with increased risk of hospitalization, ICU admission, and need for artificial ventilation and of ocrelizumab with hospitalization and ICU admission. Despite the cross-sectional design of the study, the internal and external consistency of these results with prior studies suggests that rituximab/ocrelizumab use may be a risk factor for more severe COVID-19.

Single-Stage Treatment of Extensive Aortic Pathology Using the Frozen Elephant Trunk Procedure.

BACKGROUND: Extensive pathology involving the aortic arch and descending aorta traditionally has been treated with two open procedures. We report our institutional experience with a single stage frozen elephant trunk procedure for treatment of extensive aortic pathology. METHODS: Between June 2018 and October 2019, nine patients (eight males, 89%, mean age 61 ± 6 years) with extensive aortic pathology were operated using the frozen elephant trunk procedure. Five (56%) patients underwent primary operation for chronic arch and proximal descending aneurysm in two (22%) patients, chronic type B aortic dissection in two (22%) patients and penetrating aortic ulcer in one (11%) patient. The other four (44%) patients received reoperative surgery for chronic post-dissection aneurysms. For organ protection during the aortic arch procedure, we used selective antegrade cerebral perfusion and mild systemic hypothermia at 28°C. RESULTS: Early mortality was not observed. A single (11%) patient developed focal stroke. Unilateral vocal cord palsy was present in two (22%) patients. Spinal cord injury was not observed. Reexploration for bleeding was required in two (22%) patients. Prolonged ventilation, liver and kidney failure as well as cardiac morbidity were not observed. Two patients (22%) with anticipated Endoleak type Ib received TEVAR extension at follow up. Mid-term mortality was observed in two (22%) patients, due to pneumonia. CONCLUSION: The frozen elephant trunk procedure can be used for a single-stage treatment of patients with extensive aortic pathology, due to chronic degenerative aneurysms or post-dissection aneurysms involving the aortic arch and the descending aorta, with acceptable mortality and morbidity.

COVID-19 in people with multiple sclerosis: A global data sharing initiative.

BACKGROUND: We need high-quality data to assess the determinants for COVID-19 severity in people with MS (PwMS). Several studies have recently emerged but there is great benefit in aligning data collection efforts at a global scale. OBJECTIVES: Our mission is to scale-up COVID-19 data collection efforts and provide the MS community with data-driven insights as soon as possible. METHODS: Numerous stakeholders were brought together. Small dedicated interdisciplinary task forces were created to speed-up the formulation of the study design and work plan. First step was to agree upon a COVID-19 MS core data set. Second, we worked on providing a user-friendly and rapid pipeline to share COVID-19 data at a global scale. RESULTS: The COVID-19 MS core data set was agreed within 48 hours. To date, 23 data collection partners are involved and the first data imports have been performed successfully. Data processing and analysis is an on-going process. CONCLUSIONS: We reached a consensus on a core data set and established data sharing processes with multiple partners to address an urgent need for information to guide clinical practice. First results show that partners are motivated to share data to attain the ultimate joint goal: better understand the effect of COVID-19 in PwMS.

Single-Stage Treatment of Aneurysm of the Distal Aortic Arch and Proximal Descending Aorta Using the Frozen Elephant Trunk Procedure. Case Report.

Aneurysms of the thoracic aorta involving the distal arch and the proximal descending aorta have traditionally been treated with two open procedures. During the first stage, the aortic arch pathology has been addressed through a median sternotomy. Several weeks or months later, a second stage followed and included completing the repair of the descending aorta through a lateral thoracotomy.We, herein, report a single stage repair of an aneurysm involving the distal aortic arch and the proximal descending aorta using the frozen elephant trunk operative technique. Vascular hybrid stent graft prosthesis, specifically designed for treatment of extensive aortic aneurysms, has been used to replace the arch component and exclude the descending aorta component of the aneurysm through a median sternotomy, using bilateral antegrade cerebral perfusion and mild systemic hypothermia for intraoperative organ protection.

Transposition of Subclavian Artery - Is It the Appropriate Choice?

INTRODUCTION: To present patients with symptomatic subclavian artery disease and treatment possibility. CASE REPORT: A 53-year-old female was admitted with vertigo and left arm claudication. Duplex-scan and MSCT arteriography verified subclavian artery occlusion. After the endovascular treatment failure, the patient was switched to surgical treatment - subclavian artery transposition. After the successful surgical treatment, the patient was discharged on the second postoperative day. If the patient is a candidate for surgery, the literature review shows good initial and long-term results after the subclavian artery transposition, and emphasizes this technique as superior. CONCLUSION: Subclavian carotid transposition is a safe and effective method of treatment in patients after endovascular treatment failure or other indication. Also, the surgical treatment is technically demanding because of the difficult access to the vessel origin, and it requires experienced surgeons.