Microscopic fractional anisotropy outperforms multiple sclerosis lesion assessment and clinical outcome associations over standard fractional anisotropy tensor

We aimed to compare the ability of diffusion tensor imaging and multi-compartment spherical mean technique to detect focal tissue damage and in distinguishing between different connectivity patterns associated with varying clinical outcomes in multiple sclerosis (MS). Seventy-six people diagnosed with MS were scanned using a SIEMENS Prisma Fit 3T magnetic resonance imaging (MRI), employing both conventional (T1w and fluid-attenuated inversion recovery) and advanced diffusion MRI sequences from which fractional anisotropy (FA) and microscopic FA (μFA) maps were generated. Using automated fiber quantification (AFQ), we assessed diffusion profiles across multiple white matter (WM) pathways to measure the sensitivity of anisotropy diffusion metrics in detecting localized tissue damage. In parallel, we analyzed structural brain connectivity in a specific patient cohort to fully grasp its relationships with cognitive and physical clinical outcomes. This evaluation comprehensively considered different patient categories, including cognitively preserved (CP), mild cognitive deficits (MCD), and cognitively impaired (CI) for cognitive assessment, as well as groups distinguished by physical impact: those with mild disability (Expanded Disability Status Scale [EDSS] <=3) and those with moderate-severe disability (EDSS >3). In our initial objective, we employed Ridge regression to forecast the presence of focal MS lesions, comparing the performance of μFA and FA. μFA exhibited a stronger association with tissue damage and a higher predictive precision for focal MS lesions across the tracts, achieving an R-squared value of .57, significantly outperforming the R-squared value of .24 for FA (p-value <.001). In structural connectivity, μFA exhibited more pronounced differences than FA in response to alteration in both cognitive and physical clinical scores in terms of effect size and number of connections. Regarding cognitive groups, FA differences between CP and MCD groups were limited to 0.5% of connections, mainly around the thalamus, while μFA revealed changes in 2.5% of connections. In the CP and CI group comparison, which have noticeable cognitive differences, the disparity was 5.6% for FA values and 32.5% for μFA. Similarly, μFA outperformed FA in detecting WM changes between the MCD and CI groups, with 5% versus 0.3% of connections, respectively. When analyzing structural connectivity between physical disability groups, μFA still demonstrated superior performance over FA, disclosing a 2.1% difference in connectivity between regions closely associated with physical disability in MS. In contrast, FA spotted a few regions, comprising only 0.6% of total connections. In summary, μFA emerged as a more effective tool than FA in predicting MS lesions and identifying structural changes across patients with different degrees of cognitive and global disability, offering deeper insights into the complexities of MS-related impairments.

International Variations in Surgical Morbidity and Mortality Post Gynaecological Oncology Surgery: A Global Gynaecological Oncology Surgical Outcomes Collaborative Led Study (GO SOAR1)

Gynaecological malignancies affect women in low and middle income countries (LMICs) at disproportionately higher rates compared with high income countries (HICs) with little known about variations in access, quality, and outcomes in global cancer care. Our study aims to evaluate international variation in post-operative morbidity and mortality following gynaecological oncology surgery between HIC and LMIC settings. Study design consisted of a multicentre, international prospective cohort study of women undergoing surgery for gynaecological malignancies (NCT04579861). Multilevel logistic regression determined relationships within three-level nested-models of patients within hospitals/countries. We enrolled 1820 patients from 73 hospitals in 27 countries. Minor morbidity (Clavien-Dindo I-II) was 26.5% (178/672) and 26.5% (267/1009), whilst major morbidity (Clavien-Dindo III-V) was 8.2% (55/672) and 7% (71/1009) for LMICs/HICs, respectively. Higher minor morbidity was associated with pre-operative mechanical bowel preparation (OR = 1.474, 95%CI = 1.054-2.061, p = 0.023), longer surgeries (OR = 1.253, 95%CI = 1.066-1.472, p = 0.006), greater blood loss (OR = 1.274, 95%CI = 1.081-1.502, p = 0.004). Higher major morbidity was associated with longer surgeries (OR = 1.37, 95%CI = 1.128-1.664, p = 0.002), greater blood loss (OR = 1.398, 95%CI = 1.175-1.664, p ≤ 0.001), and seniority of lead surgeon, with junior surgeons three times more likely to have a major complication (OR = 2.982, 95%CI = 1.509-5.894, p = 0.002). Of all surgeries, 50% versus 25% were performed by junior surgeons in LMICs/HICs, respectively. We conclude that LMICs and HICs were associated with similar post-operative major morbidity. Capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention.

Diffusion tensor imaging metrics associated with future disability in multiple sclerosis

The relationship between brain diffusion microstructural changes and disability in multiple sclerosis (MS) remains poorly understood. We aimed to explore the predictive value of microstructural properties in white (WM) and grey matter (GM), and identify areas associated with mid-term disability in MS patients. We studied 185 patients (71% female; 86% RRMS) with the Expanded Disability Status Scale (EDSS), timed 25-foot walk (T25FW), nine-hole peg test (9HPT), and Symbol Digit Modalities Test (SDMT) at two time-points. We used Lasso regression to analyse the predictive value of baseline WM fractional anisotropy and GM mean diffusivity, and to identify areas related to each outcome at 4.1 years follow-up. Motor performance was associated with WM (T25FW: RMSE = 0.524, R² = 0.304; 9HPT dominant hand: RMSE = 0.662, R² = 0.062; 9HPT non-dominant hand: RMSE = 0.649, R² = 0.139), and SDMT with GM diffusion metrics (RMSE = 0.772, R² = 0.186). Cingulum, longitudinal fasciculus, optic radiation, forceps minor and frontal aslant were the WM tracts most closely linked to motor dysfunction, and temporal and frontal cortex were relevant for cognition. Regional specificity related to clinical outcomes provide valuable information that can be used to develop more accurate predictive models that could improve therapeutic strategies.

Consensus statement on the use of alemtuzumab in daily clinical practice in Spain

INTRODUCTION

Alemtuzumab is a highly effective drug approved by the European Medicines Agency as a disease-modifying drug for the treatment of relapsing-remitting multiple sclerosis.

OBJECTIVE

A consensus document was drafted on the management of alemtuzumab in routine clinical practice in Spain.

DEVELOPMENT

A group of multiple sclerosis specialists reviewed articles addressing treatment with alemtuzumab in patients with multiple sclerosis and published before December 2017. The included studies assessed the drug's efficacy, effectiveness, and safety; screening for infections and vaccination; and administration and monitoring aspects. The initial proposed recommendations were developed by a coordinating group and based on the available evidence and their clinical experience. The consensus process was carried out in 2 stages, with the initial threshold percentage for group agreement established at 80%. The final document with all the recommendations agreed by the working group was submitted for external review and the comments received were considered by the coordinating group.

CONCLUSION

The present document is intended to be used as a tool for optimising the management of alemtuzumab in routine clinical practice.

Surgical window-of-opportunity study of megestrol acetate compared with megestrol acetate and metformin for endometrial intraepithelial neoplasia

TPS5601

Background: Endometrial Intraepithelial Neoplasia (EIN) is a precursor lesion to endometrial carcinoma (EC), the most common gynecologic cancer among women in the US. The current standard of care for women with EIN is hysterectomy. Non-surgical treatments are needed for women desiring fertility preservation, and for those who are medically unfit for a major surgical procedure. Progestin therapy is the cornerstone of current nonsurgical management of EIN. However, approximately 30% of patients with EIN do not respond to progestin therapy, or respond incompletely. EIN is closely related to insulin resistance and metabolic syndrome with evidence that increased insulin resistance is a significant risk factor for development of EC. Metformin, an inhibitor of insulin/PI3K/AKT pathway, has been demonstrated to reduce endometrial proliferation in vitro and in vivo. We hypothesize that the combination of metformin and progestin therapy may synergize to arrest EIN progression and prevent the development of EC. Methods: This is a randomized pre-surgical window of opportunity study, comparing a commonly used oral progestin, megestrol acetate (MA), to MA and metformin (M). Patients with pathologically confirmed EIN or complex atypical hyperplasia (CAH) who present for hysterectomy will be approached. After enrollment, participants will receive MA 80mg PO BID ± M 500mg BID for 4 ± 1 weeks pre-operatively. Post-therapy endometrial biopsy will be obtained in the operating room prior to the hysterectomy, and compared to the pre-therapy diagnostic endometrial biopsy sample. The primary endpoint is the change in the percentage (%) of Ki-67 expressing cells (%Ki-67) between the pre- and post-treatment biopsies. Based on a two-sample t-test comparing the pre- to post-treatment changes in %Ki-67 between the two arms, a sample size of 21 patients per arm achieves 80% power with two-sided α = 0.05 to detect an absolute reduction in %Ki-67 of 10% vs. 17.6% in the MA vs. MA + M arms. An interim analysis is planned after enrollment of 32 patients, and an internal pilot approach based on variance re-estimation will be used to increase the sample size if needed, to maintain the original planned power. Secondary endpoints will include comparison of changes in protein expression of ER, PR, PTEN/PAX2, markers of the PI3K/AKT/MTOR pathway, cell death and intratumoral insulin signaling. We will randomize 50 subjects at five sites: Northwestern University, Cedars-Sinai (Los Angeles), Duke University, University of Colorado, and University of North Carolina. Participants will be randomized 1:1 and stratified by menopausal status to ensure balance between the two arms. Since September 2021, four sites have opened and 22 patients have been pre-screened. Three participants were enrolled and two have completed intervention. The study is expected to complete accrual by the end of 2023. Clinical trial information: NCT04576104.

Determining post-operative morbidity and mortality following gynecological oncology surgery: protocol for a multicenter, international, prospective cohort study (Global Gynaecological Oncology Surgical Outcomes Collaborative-GO SOAR)

BACKGROUND

The Global Gynaecological Oncology Surgical Outcomes Collaborative (GO SOAR) aims to develop a network of gynecological oncology surgeons, surgical departments, and other interested parties that will have the long-term ability to collaborate on outcome studies. The protocol for the first collaborative study is presented here.

PRIMARY OBJECTIVE

To evaluate international variation in 30-day post-operative morbidity and mortality following gynecological oncology surgery between very high/high and medium/low human development index country settings.

HYPOTHESIS

There is no variation in post-operative morbidity and mortality following gynecological oncology surgery between very high/high and medium/low human development index country settings.

STUDY DESIGN

International, multicenter, prospective cohort study. Patient data will be collected over a consecutive 30-day period through gynecological oncology multidisciplinary teams/tumor boards and clinics across different human development index country groups. All data are collected on a customized, secure, password protected, central REDCap database.

MAJOR INCLUSION/EXCLUSION CRITERIA

Inclusion criteria include women aged ≥18 years undergoing elective/emergency, curative/palliative surgery for primary/recurrent tubo-ovarian/peritoneal, endometrial, cervical, vulval, vaginal, gestational trophoblastic malignancies. Surgical modality may be open, minimal access (laparoscopic/robotic), or vaginal.

PRIMARY ENDPOINT

30-day post-operative morbidity and mortality defined as per Clavien-Dindo classification system.

SAMPLE SIZE

1100 (550/arm).

ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS

It is estimated recruitment will be completed by 2022 and results published by 2023.

TRIAL REGISTRATION

ClinicalTrials.gov registry: NCT04579861 (https://clinicaltrials.gov/ct2/show/NCT04579861).

Impact of SARS-CoV-2 on training and mental well-being of surgical gynecological oncology trainees

INTRODUCTION

The SARS-CoV-2 global pandemic has caused a crisis disrupting health systems worldwide. While efforts are being made to determine the extent of the disruption, the impact on gynecological oncology trainees/training has not been explored. We conducted an international survey of the impact of SARS-CoV-2 on clinical practice, medical education, and mental well-being of surgical gynecological oncology trainees.

METHODS

In our cross-sectional study, a customized web-based survey was circulated to surgical gynecological oncology trainees from national/international organizations from May to November 2020. Validated questionnaires assessed mental well-being. The Wilcoxon rank-sum test and Fisher's exact test were used to analyse differences in means and proportions. Multiple linear regression was used to evaluate the effect of variables on psychological/mental well-being outcomes. Outcomes included clinical practice, medical education, anxiety and depression, distress, and mental well-being.

RESULTS

A total of 127 trainees from 34 countries responded. Of these, 52% (66/127) were from countries with national training programs (UK/USA/Netherlands/Canada/Australia) and 48% (61/127) from countries with no national training programs. Altogether, 28% (35/125) had suspected/confirmed COVID-19, 28% (35/125) experienced a fall in household income, 20% (18/90) were self-isolated from households, 45% (57/126) had to re-use personal protective equipment, and 22% (28/126) purchased their own. In total, 32.3% (41/127) of trainees (16.6% (11/66) from countries with a national training program vs 49.1% (30/61) from countries with no national training program, p=0.02) perceived they would require additional time to complete their training fellowship. The additional training time anticipated did not differ between trainees from countries with or without national training programs (p=0.11) or trainees at the beginning or end of their fellowship (p=0.12). Surgical exposure was reduced for 50% of trainees. Departmental teaching continued throughout the pandemic for 69% (87/126) of trainees, although at reduced frequency for 16.1% (14/87), and virtually for 88.5% (77/87). Trainees reporting adequate pastoral support (defined as allocation of a dedicated mentor/access to occupational health support services) had better mental well-being with lower levels of anxiety/depression (p=0.02) and distress (p<0.001). Trainees from countries with a national training program experienced higher levels of distress (p=0.01). Mean (SD) pre-pandemic mental well-being scores were significantly higher than post-pandemic scores (8.3 (1.6) vs 7 (1.8); p<0.01).

CONCLUSION

SARS-CoV-2 has negatively impacted the surgical training, household income, and psychological/mental well-being of surgical gynecological oncology trainees. The overall clinical impact was worse for trainees in countries with no national training program than for those in countries with a national training program, although national training program trainees reported greater distress. COVID-19 sickness increased anxiety/depression. The recovery phase must focus on improving mental well-being and addressing lost training opportunities.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Risk factors for potentially avoidable readmissions following gynecologic oncology surgery

OBJECTIVE

Determine the incidence and identify factors associated with potentially avoidable hospital readmissions due to uncontrolled symptoms or minor complications after surgery for gynecologic cancers.

METHODS

Women who underwent major abdominal or pelvic surgery for a gynecologic malignancy between 2015 and 2017 were identified from the National Surgical Quality Improvement Program targeted hysterectomy dataset. Hospital readmissions within 30 days of surgery were categorized as indicated readmissions or potentially avoidable readmissions by three independent reviewers. Demographic, clinical, and operative covariates were evaluated to determine their association with type of readmission using bivariable tests and adjusted multinomial logistic regression models.

RESULTS

A total of 20,986 women were identified. 19,814 (94.4%) were not readmitted, 894 (4.3%) were indicated readmissions, and 278 (1.3%) were potentially avoidable readmissions. Among those readmitted, 24% were potentially avoidable readmissions. Presence of ascites, increasing length of stay, and discharge to facility were associated with an increased risk of indicated and potentially avoidable readmissions. Age < 60 years old (RR 1.4, 95%CI 1.1-1.8), BMI ≥ 30 (RR 1.7, 95%CI 1.3-2.3), history of abdominal/pelvic surgery (RR 1.6, 95%CI 1.2-2.1), cervical cancer (RR 2.1, 95%CI 1.4-3.1), and open surgery (RR 2.1, 95%CI 1.4-3.2) were associated with an increased risk of a potentially avoidable readmission but not with increased risk of an indicated readmission. Median time to readmission did not differ between the two readmission groups (indicated = 8 days; avoidable = 7 days; p = .72).

CONCLUSIONS

Among women with gynecologic cancer, 24% of all unplanned readmissions were attributed to uncontrolled symptoms or minor complications that were potentially avoidable. Age <60 years old, history of previous abdominal/pelvic surgery, obesity, cervical cancer, and open surgery were associated with an increase in risk of a potentially avoidable readmission.

[Recommendations for the use of cladribine tablets in recurring multiple sclerosis]

INTRODUCTION

Cladribine is a prodrug, a synthetic analogue of deoxyadenosine, approved for use as selective immune reconstitution therapy in very active recurring multiple sclerosis in adults.

AIMS

To review the development of the drug, its mechanism of action and the efficacy and safety data obtained to date, as well as to establish recommendations of Spanish experts for its use in clinical practice.

DEVELOPMENT

The treatment of multiple sclerosis has been simplified with cladribine tablets, and two short courses of administration for two consecutive years (maximum 20 days) are needed to maintain an efficacy of up to four years after the first dose. Results of clinical trials have demonstrated the safety, tolerability and long-term efficacy of cladribine tablets in patients with recurring multiple sclerosis. Thus, patients treated with cladribine presented a significant reduction in the rate of flare-ups, in the risk of disability progression and in the development of new lesions in magnetic resonance imaging compared to those treated with placebo. In terms of safety, the treated patients had a higher frequency of lymphopenia, in relation to its mechanism of action, and of infections by herpes zoster virus. Long-term results with eight years' follow-up have shown that treated patients are not at greater risk of developing serious events, such as malignant neoplasms or opportunistic infections.

CONCLUSIONS

Cladribine is the first short-course oral therapy that has been shown to be effective and safe in patients with very active recurring multiple sclerosis, and with a sustained effect over time. The recommendations of Spanish experts on its usage are a fundamental complement to the considerations described by the regulatory agencies.

Review of the novelties presented at the 2018 ECTRIMS Congress: 11th Post-ECTRIMS Meeting (II)

The Post-ECTRIMS Meeting was held for the eleventh consecutive year in October 2018 in Madrid, with the aim of analysing the advances made in multiple sclerosis that were highlighted at the latest ECTRIMS annual congress. Based on the issues discussed at this meeting, attended by the nation's foremost opinion leaders on multiple sclerosis, two review articles are presented. This second part includes the growing body of evidence confirming the safety of exposure to disease-modifying treatments in women planning a pregnancy, and the beneficial effect of breastfeeding, provided that the disease is not very active. It addresses data showing how the application of the 2017 McDonald criteria in the paediatric population has significantly improved diagnosis compared to the previous criteria. With regard to progressive multiple sclerosis, the results of neuroprotective drugs are inconclusive, but biomarkers are proposed to improve the evaluation of the therapeutic response. Studies on myelin repair treatments suggest that remyelination in multiple sclerosis is possible. Likewise, there are favourable indications for haematopoietic stem cell transplantation, provided that patients are selected appropriately. On the other hand, we also conduct a review of the similarities and differences of the recommendations in the new clinical practice guidelines. Finally, the positive results of cognitive and motor rehabilitation with the use of new technologies point to the systematic incorporation of these tools in the treatment of the disease in the near future.

[Review of the novelties presented at the 2018 ECTRIMS Congress: 11th Post-ECTRIMS Meeting (I)]

The Post-ECTRIMS Meeting is an emblematic event in Spain which seeks to review and disseminate the main advances in multiple sclerosis presented at the ECTRIMS annual congress. In October 2018, the eleventh Post-ECTRIMS meeting was held in Madrid and was attended by the country's leading experts in multiple sclerosis. As a result of this meeting, we present two articles which outline the most interesting novelties discussed there. This first part includes the latest results obtained regarding the influence of modifiable and non-modifiable risk factors in multiple sclerosis, with emphasis on the progress made in the field of genetics, where the discovery of genes associated with multiple sclerosis has increased exponentially. The complexity of the immune system is addressed and some contributions are made on autoimmunity mechanisms, in which bidirectional relations are observed between immune cells and cells residing in the central nervous system, such as microglial cells and astrocytes. Biomarkers, both in serum and cerebrospinal fluid as well as in imaging, are gaining more and more attention due to their current and, above all, potential role in the diagnosis and prognosis of the disease and in the evaluation of the efficacy of treatments. Finally, the observations made regarding changes in structural and functional connectivity in patients and their relationship with clinical alterations are presented.

Kappa free light chains is a valid tool in the diagnostics of MS: A large multicenter study

OBJECTIVE

To validate kappa free light chain (KFLC) and lambda free light chain (LFLC) indices as a diagnostic biomarker in multiple sclerosis (MS).

METHODS

We performed a multicenter study including 745 patients from 18 centers (219 controls and 526 clinically isolated syndrome (CIS)/MS patients) with a known oligoclonal IgG band (OCB) status. KFLC and LFLC were measured in paired cerebrospinal fluid (CSF) and serum samples. Gaussian mixture modeling was used to define a cut-off for KFLC and LFLC indexes.

RESULTS

The cut-off for the KFLC index was 6.6 (95% confidence interval (CI) = 5.2-138.1). The cut-off for the LFLC index was 6.9 (95% CI = 4.5-22.2). For CIS/MS patients, sensitivity of the KFLC index (0.88; 95% CI = 0.85-0.90) was higher than OCB (0.82; 95%CI = 0.79-0.85; p < 0.001), but specificity (0.83; 95% CI = 0.78-0.88) was lower (OCB = 0.92; 95% CI = 0.89-0.96; p < 0.001). Both sensitivity and specificity for the LFLC index were lower than OCB.

CONCLUSION

Compared with OCB, the KFLC index is more sensitive but less specific for diagnosing CIS/MS. Lacking an elevated KFLC index is more powerful for excluding MS compared with OCB but the latter is more important for ruling in a diagnosis of CIS/MS.

[Review of the novelties from the 2017 ECTRIMS Congress, presented at the 10th Post-ECTRIMS Meeting (II)]

The Post-ECTRIMS Meeting is an emblematic event in the field of multiple sclerosis in Spain. Its chief aim is bring together the country's leading specialist neurologists to analyse the main advances made in multiple sclerosis and to review the most important topics addressed at the ECTRIMS Congress. The tenth Post-ECTRIMS Meeting was held in November 2017. Over the years this event has firmly established itself as an important meeting point where experts from all over the country get together to foster communication, establish synergies and promote and enhance research ultimately aimed at improving the prognosis and quality of life of patients with multiple sclerosis. This second part addresses the different strategies for the management of patients in advanced stages of the disease and the safety of therapy in multiple sclerosis. Likewise, attention is also drawn to the areas that require further scientific and clinical evidence. In this edition, particular importance is given to multiple sclerosis in the paediatric population and ageing in the disease. At the same time emphasis is placed on the need to conduct collaborative studies and to foster greater awareness among specialists regarding the detection and management of the comorbidities in multiple sclerosis.

[Review of the novelties from the 2017 ECTRIMS Congress, presented at the 10th Post-ECTRIMS Meeting (I)]

The Post-ECTRIMS Meeting is an emblematic event in the field of multiple sclerosis in Spain. Its chief aim is bring together the country's leading specialist neurologists to analyse the main advances made in multiple sclerosis and to review the most important topics addressed at the ECTRIMS Congress. The tenth Post-ECTRIMS Meeting was held in November 2017. Over the years this event has firmly established itself as an important meeting point where experts from all over the country get together to foster communication, establish synergies and promote and enhance research ultimately aimed at improving the prognosis and quality of life of patients with multiple sclerosis. This first part reports on the publication of the new European and American clinical guidelines on the use of disease-modifying treatments and the new diagnostic criteria. It also discusses the strategies for following up patients treated with disease-modifying therapies, reviews cerebral atrophy and biomarkers of neurodegeneration and neuroinflammation, and analyses the role of neuroglia in pathogenesis and treatment. The study examines the natural history of the disease, with the evidence provided by registers, and we anticipate the future thanks to the progress being made in genetics and immunology.

MOG encephalomyelitis: international recommendations on diagnosis and antibody testing

Over the past few years, new-generation cell-based assays have demonstrated a robust association of autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis and brainstem encephalitis, as well as with acute disseminated encephalomyelitis (ADEM)-like presentations. Most experts now consider MOG-IgG-associated encephalomyelitis (MOG-EM) a disease entity in its own right, immunopathogenetically distinct from both classic multiple sclerosis (MS) and aquaporin-4 (AQP4)-IgG-positive neuromyelitis optica spectrum disorders (NMOSD). Owing to a substantial overlap in clinicoradiological presentation, MOG-EM was often unwittingly misdiagnosed as MS in the past. Accordingly, increasing numbers of patients with suspected or established MS are currently being tested for MOG-IgG. However, screening of large unselected cohorts for rare biomarkers can significantly reduce the positive predictive value of a test. To lessen the hazard of overdiagnosing MOG-EM, which may lead to inappropriate treatment, more selective criteria for MOG-IgG testing are urgently needed. In this paper, we propose indications for MOG-IgG testing based on expert consensus. In addition, we give a list of conditions atypical for MOG-EM ("red flags") that should prompt physicians to challenge a positive MOG-IgG test result. Finally, we provide recommendations regarding assay methodology, specimen sampling and data interpretation.