Rapid artefact removal and H&E-stained tissue segmentation.

We present an innovative method for rapidly segmenting haematoxylin and eosin (H&E)-stained tissue in whole-slide images (WSIs) that eliminates a wide range of undesirable artefacts such as pen marks and scanning artefacts. Our method involves taking a single-channel representation of a low-magnification RGB overview of the WSI in which the pixel values are bimodally distributed such that H&E-stained tissue is easily distinguished from both background and a wide variety of artefacts. We demonstrate our method on 30 WSIs prepared from a wide range of institutions and WSI digital scanners, each containing substantial artefacts, and compare it to segmentations provided by Otsu thresholding and Histolab tissue segmentation and pen filtering tools. We found that our method segmented the tissue and fully removed all artefacts in 29 out of 30 WSIs, whereas Otsu thresholding failed to remove any artefacts, and the Histolab pen filtering tools only partially removed the pen marks. The beauty of our approach lies in its simplicity: manipulating RGB colour space and using Otsu thresholding allows for the segmentation of H&E-stained tissue and the rapid removal of artefacts without the need for machine learning or parameter tuning.

Standards for clinical trials for treating TB.

BACKGROUND: The value, speed of completion and robustness of the evidence generated by TB treatment trials could be improved by implementing standards for best practice.METHODS: A global panel of experts participated in a Delphi process, using a 7-point Likert scale to score and revise draft standards until consensus was reached.RESULTS: Eleven standards were defined: Standard 1, high quality data on TB regimens are essential to inform clinical and programmatic management; Standard 2, the research questions addressed by TB trials should be relevant to affected communities, who should be included in all trial stages; Standard 3, trials should make every effort to be as inclusive as possible; Standard 4, the most efficient trial designs should be considered to improve the evidence base as quickly and cost effectively as possible, without compromising quality; Standard 5, trial governance should be in line with accepted good clinical practice; Standard 6, trials should investigate and report strategies that promote optimal engagement in care; Standard 7, where possible, TB trials should include pharmacokinetic and pharmacodynamic components; Standard 8, outcomes should include frequency of disease recurrence and post-treatment sequelae; Standard 9, TB trials should aim to harmonise key outcomes and data structures across studies; Standard 10, TB trials should include biobanking; Standard 11, treatment trials should invest in capacity strengthening of local trial and TB programme staff.CONCLUSION: These standards should improve the efficiency and effectiveness of evidence generation, as well as the translation of research into policy and practice.

Stain normalization gives greater generalizability than stain jittering in neural network training for the classification of coeliac disease in duodenal biopsy whole slide images.

Around 1% of the population of the UK and North America have a diagnosis of coeliac disease (CD), due to a damaging immune response to the small intestine. Assessing whether a patient has CD relies primarily on the examination of a duodenal biopsy, an unavoidably subjective process with poor inter-observer concordance. Wei et al. [11] developed a neural network-based method for diagnosing CD using a dataset of duodenal biopsy whole slide images (WSIs). As all training and validation data came from one source, there was no guarantee that their results would generalize to WSIs obtained from different scanners and laboratories. In this study, the effects of applying stain normalization and jittering to the training data were compared. We trained a deep neural network on 331 WSIs obtained with a Ventana scanner (WSIs; CD: n=190; normal: n=141) to classify presence of CD. In order to test the effects of stain processing when validating on WSIs scanned on varying scanners and from varying laboratories, the neural network was validated on 4 datasets: WSIs of slides scanned on a Ventana scanner (WSIs; CD: n=48; normal: n=35), WSIs of the same slides rescanned on a Hamamatsu scanner (WSIs; CD: n=48; normal: n=35), WSIs of the same slides rescanned on an Aperio scanner (WSIs; CD: n=48; normal: n=35), and WSIs of different slides scanned on an Aperio scanner (WSIs; CD: n=38; normal: n=37). Without stain processing, the F1 scores of the neural network were 0.947, 0.619, 0.746, and 0.727 when validating on the Ventana validation WSIs, Hamamatsu and Aperio rescans of the Ventana validation WSIs, and Aperio WSIs from a different source respectively. With stain normalization, the performance of the neural network improved significantly with respective F1 scores 0.982, 0.943, 0.903, and 0.847. Stain jittering resulted in a better performance than stain normalization when validating on data from the same source F1 score 1.000, but resulted in poorer performance than stain normalization when validating on WSIs from different scanners (F1 scores 0.939, 0.814, and 0.747). This study shows the importance of stain processing, in particular stain normalization, when training machine learning models on duodenal biopsy WSIs to ensure generalizability between different scanners and laboratories.

A systematic review of the costs of diagnosis for multidrug-resistant/extensively drug-resistant TB in different settings.

BACKGROUND: We performed an analysis of the cost and relative merits of different strategies for the diagnosis of multidrug-resistant/extensively drug-resistant TB (MDR/XDR-TB) in different settings.METHODS: We systematically reviewed the published evidence on cost/cost-effectiveness of rapid MDR/pre-XDR-TB and other methods for XDR-TB testing up to September 2022. PRISMA guidelines were followed. Collected data were analysed using Stata v17 software. Cost data were reported in USD ($) and summarised by mean, standard deviation, and range. Country income level was defined according to the World Bank country classification. Three simplified scenarios were also used to explore testing implications, based on low, intermediate and high TB incidence.RESULTS: Of 157 records, 25 studies were included with 24 reporting the cost of Xpert/RIF and two that evaluated the implementation of the MTBDRplus test. The total rapid test cost ranged from $12.41-$218, including $1.13-$74.60 for reagents/consumables and $0.40-$14.34 for equipment.CONCLUSION: The cost of MDR/XDR-TB diagnostics is lower in low resource settings. However, the cost-effective implementation of MDR/XDR-TB diagnostic algorithms requires careful consideration of local resources to avoid missed identification and the use of inappropriate regimen.

Clinical standards for drug-susceptible pulmonary TB.

BACKGROUND: The aim of these clinical standards is to provide guidance on 'best practice´ for diagnosis, treatment and management of drug-susceptible pulmonary TB (PTB).METHODS: A panel of 54 global experts in the field of TB care, public health, microbiology, and pharmacology were identified; 46 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all 46 participants.RESULTS: Seven clinical standards were defined: Standard 1, all patients (adult or child) who have symptoms and signs compatible with PTB should undergo investigations to reach a diagnosis; Standard 2, adequate bacteriological tests should be conducted to exclude drug-resistant TB; Standard 3, an appropriate regimen recommended by WHO and national guidelines for the treatment of PTB should be identified; Standard 4, health education and counselling should be provided for each patient starting treatment; Standard 5, treatment monitoring should be conducted to assess adherence, follow patient progress, identify and manage adverse events, and detect development of resistance; Standard 6, a recommended series of patient examinations should be performed at the end of treatment; Standard 7, necessary public health actions should be conducted for each patient. We also identified priorities for future research into PTB.CONCLUSION: These consensus-based clinical standards will help to improve patient care by guiding clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment for PTB.

Risk factors for TB in Australia and their association with delayed treatment completion.

BACKGROUND: Australia has a low incidence of TB and has committed to eliminating the disease. Identification of risk factors associated with TB is critical to achieving this goal.METHODS: We undertook a prospective cohort study involving persons receiving TB treatment in four Australian jurisdictions. Risk factors and their association with delayed treatment completion (treatment delayed by at least 1 month) were analysed using univariate analyses and multivariate logistic regression.RESULTS: Baseline surveys were completed for 402 persons with TB. Most (86.1%) were born overseas. Exposure to a person with TB was reported by 19.4%. Diabetes mellitus (10.2%), homelessness (9.2%), cigarette smoking (8.7%), excess alcohol consumption (6.0%) and mental illness (6.2%) were other common risk factors. At follow-up, 24.8% of patients had delayed treatment completion, which was associated with adverse events (34.1%, aOR 6.67, 95% CI 3.36-13.27), excess alcohol consumption (6.0%, aOR 21.94, 95% CI 6.03-79.85) and HIV co-infection (2.7%, aOR 8.10, 95% CI 1.16-56.60).CONCLUSIONS: We identified risk factors for TB and their association with delayed treatment completion, not all of which are routinely collected for surveillance purposes. Recognition of these risk factors should facilitate patient-centred care and assist Australia in reaching TB elimination.

Clinical standards for the diagnosis, treatment and prevention of TB infection.

BACKGROUND: Tuberculosis (TB) preventive therapy (TPT) decreases the risk of developing TB disease and its associated morbidity and mortality. The aim of these clinical standards is to guide the assessment, management of TB infection (TBI) and implementation of TPT.METHODS: A panel of global experts in the field of TB care was identified; 41 participated in a Delphi process. A 5-point Likert scale was used to score the initial standards. After rounds of revision, the document was approved with 100% agreement.RESULTS: Eight clinical standards were defined: Standard 1, all individuals belonging to at-risk groups for TB should undergo testing for TBI; Standard 2, all individual candidates for TPT (including caregivers of children) should undergo a counselling/health education session; Standard 3, testing for TBI: timing and test of choice should be optimised; Standard 4, TB disease should be excluded prior to initiation of TPT; Standard 5, all candidates for TPT should undergo a set of baseline examinations; Standard 6, all individuals initiating TPT should receive one of the recommended regimens; Standard 7, all individuals who have started TPT should be monitored; Standard 8, a TBI screening and testing register should be kept to inform the cascade of care.CONCLUSION: This is the first consensus-based set of Clinical Standards for TBI. This document guides clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage TBI.

Multiple-instance-learning-based detection of coeliac disease in histological whole-slide images.

We present a multiple-instance-learning-based scheme for detecting coeliac disease, an autoimmune disorder affecting the intestine, in histological whole-slide images (WSIs) of duodenal biopsies. We train our model to detect 2 distinct classes, normal tissue and coeliac disease, on the patch-level, and in turn leverage slide-level classifications. Using 5-fold cross-validation in a training set of 1841 (1163 normal; 680 coeliac disease) WSIs, our model classifies slides as normal with accuracy (96.7±0.6)%, precision (98.0±1.7)%, and recall (96.8±2.5)%, and as coeliac disease with accuracy (96.7±0.5)%, precision (94.9±3.7)%, and recall (96.5±2.9)% where the error bars are the cross-validation standard deviation. We apply our model to 2 test sets: one containing 191 WSIs (126 normal; 65 coeliac) from the same sources as the training data, and another from a completely independent source, containing 34 WSIs (17 normal; 17 coeliac), obtained with a scanner model not represented in the training data. Using the same-source test data, our model classifies slides as normal with accuracy 96.5%, precision 98.4% and recall 96.1%, and positive for coeliac disease with accuracy 96.5%, precision 93.5%, and recall 97.3%. Using the different-source test data the model classifies slides as normal with accuracy 94.1% (32/34), precision 89.5%, and recall 100%, and as positive for coeliac disease with accuracy 94.1%, precision 100%, and recall 88.2%. We discuss generalising our approach to screen for a range of pathologies.

Receiving healthcare for drug-resistant TB: a cross-sectional survey from Pakistan.

OBJECTIVE: To describe and quantify patients' self-reported experiences of receiving healthcare from Pakistan's Programmatic Management of Drug-Resistant Tuberculosis (PMDT) model of care, and to understand these experiences within the broader context of Pakistan's health system. METHOD: This was a cross-sectional survey of patients attending three PMDT clinics in Khyber-Pakhtunkhwa Province in Pakistan. RESULTS: The median consultation time at the PMDT clinics was 10 minutes. In their most recent visit to the PMDT clinic, 34.9% of patients spent >40% of their monthly income to access treatment. To specify, 71% of patients reported spending out-of-pocket for ancillary medicines and 44.7% for laboratory tests. In 10.5% of cases, medicines for drug-resistant TB (DR-TB) were dispensed without the patient attending the clinic. Only 43.7% of treatment supporters regularly accompanied patients to the clinic, and 6% supervised the patient's intake of medicines. Disbursement of financial support was irregular in 98.6% of cases. Only 6.2% of patients received their daily injections from a public facility, the rest went elsewhere. CONCLUSION: Several shortcomings in PMDT services, including hurried consultations, irregularities in financial support, and gaps in Pakistan's broader health system undermined healthcare experience of patients with DR-TB. To improve health outcomes and patients' care experience these service gaps need to be addressed.

TB contact tracing for young children: an Australian cascade of care review.

OBJECTIVE: To evaluate care cascades for programmatic active case finding and latent TB infection (LTBI) management in young child TB contacts (aged <5 years) in Victoria, Australia. DESIGN: This was a retrospective review of public health surveillance data to identify contacts of all pulmonary TB cases notified from 2016 to 2019. RESULTS: Contact tracing identified 574 young child contacts of 251 pulmonary TB cases. Active TB was found in 28 (4.9%) contacts, none of whom had previously received bacille Calmette-Guérin vaccination, and 529 were tested for TB infection using the tuberculin skin test (TST). The overall TST positivity was 15.3% (95% CI 0.1-0.2). Among the 574 children, 150 (26.1%) were close contacts of sputum smear-positive cases and 25 (16.7%) of these were not referred to TB clinics. Of the 125 referred, 81 were considered to have LTBI, 79 agreed to commence TB preventive treatment (TPT) and 71 (89.9%) completed TPT. Following completion of TPT, no child was subsequently diagnosed with active TB. CONCLUSION: There was a high yield from active case finding and uptake of TPT. Notable losses in the cascade of care occurred around referral to tertiary clinics, but high treatment completion rates and good outcomes were found in those prescribed treatment.

OBJECTIF: Evaluer les cascades de soins pour la recherche active programmatique des cas et la prise en charge de l'infection tuberculeuse latente (ITL) chez les contacts de jeunes patients atteints de TB âgés de <5 ans dans l'état de Victoria, Australie. SCHÉMA: Revue rétrospective de données de surveillance de santé publique afin d'identifier les contacts de tous les cas de TB pulmonaire notifiés de 2016 à 2019. RÉSULTATS: Le traçage des contacts a identifié 574 jeunes enfants tous contacts de 251 cas de TB pulmonaire. Une TB active a été trouvée chez 28 enfants contacts (4,9%), aucun n'ayant reçu le vaccin bacille Calmette-Guérin, et 529 ont été testés à la recherche d'infection TB avec un test cutané à la tuberculine (TCT). La positivité d'ensemble du TCT a été de 15,3% (IC 95% 0,1­0,2). Parmi les 574 enfants, 150 (26,1%) étaient des contacts étroits de cas à frottis de crachats positifs et 25 (16,7%) d'entre eux n'ont pas été référés dans des structures TB. Sur les 125 enfants référés, 81 ont été considérés comme ayant une ITL, 79 ont accepté de débuter un traitement préventif (TPT) et 71 (89,9%) l'ont terminé. Aucun enfant n'a ensuite eu de diagnostic de TB active. CONCLUSION: La recherche active de cas et la couverture TPT ont eu un rendement élevé. Des pertes notables dans la cascade de soins sont survenues lors de référence aux structures tertiaires, mais ceux qui ont reçu un traitement ont eu un taux élevé d'achèvement et de bons résultats.

Active case-finding in contacts of people with TB.

BACKGROUND: Exposure to people with TB substantially elevates a person's risk of tuberculous infection and TB disease. Systematic screening of TB contacts enables the early detection and treatment of co-prevalent disease, and the opportunity to prevent future TB disease. However, scale-up of contact investigation in high TB transmission settings remains limited.METHODS: We undertook a narrative review to evaluate the evidence for contact investigation and identify strategies that TB programmes may consider when introducing contact investigation and management.RESULTS: Selection of contacts for priority screening depends upon their proximity and duration of exposure, along with their susceptibility to develop TB. Screening algorithms can be tailored to the target population, the availability of diagnostic tests and preventive therapy, and healthcare worker expertise. Contact investigation may be performed in the household or at communal locations. Local contact investigation policies should support vulnerable patients, and ensure that drop-out during screening can be mitigated. Ethical issues should be anticipated and addressed in each setting.CONCLUSION: Contact investigation is an important strategy for TB elimination. While its epidemiological impact will be greatest in lower-transmission settings, the early detection and prevention of TB have important benefits for contacts and their communities.

Outcome of treatment of MDR-TB or drug-resistant patients treated with bedaquiline and delamanid: Results from a large global cohort.

The World Health Organization (WHO) recommends countries introduce new anti-TB drugs in the treatment of multidrug-resistant tuberculosis. The aim of the study is to prospectively evaluate the effectiveness of bedaquiline (and/or delamanid)- containing regimens in a large cohort of consecutive TB patients treated globally. This observational, prospective study is based on data collected and provided by Global Tuberculosis Network (GTN) centres and analysed twice a year. All consecutive patients (including children/adolescents) treated with bedaquiline and/or delamanid were enrolled, and managed according to WHO and national guidelines. Overall, 52 centres from 29 countries/regions in all continents reported 883 patients as of January 31st 2021, 24/29 countries/regions providing data on 100% of their consecutive patients (10-80% in the remaining 5 countries). The drug-resistance pattern of the patients was severe (>30% with extensively drug-resistant -TB; median number of resistant drugs 5 (3-7) in the overall cohort and 6 (4-8) among patients with a final outcome). For the patients with a final outcome (477/883, 54.0%) the median (IQR) number of months of anti-TB treatment was 18 (13-23) (in days 553 (385-678)). The proportion of patients achieving sputum smear and culture conversion ranged from 93.4% and 92.8% respectively (whole cohort) to 89.3% and 88.8% respectively (patients with a final outcome), a median (IQR) time to sputum smear and culture conversion of 58 (30-90) days for the whole cohort and 60 (30-100) for patients with a final outcome and, respectively, of 55 (30-90) and 60 (30-90) days for culture conversion. Of 383 patients treated with bedaquiline but not delamanid, 284 (74.2%) achieved treatment success, while 25 (6.5%) died, 11 (2.9%) failed and 63 (16.5%) were lost to follow-up.

High-degeneracy Potts coarsening.

I examine the fate of a kinetic Potts ferromagnet with a high ground-state degeneracy that undergoes a deep quench to zero temperature. I consider single spin-flip dynamics on triangular lattices of linear dimension 8≤L≤128 and set the number of spin states q equal to the number of lattice sites L×L. The ground state is the most abundant final state, and is reached with probability ≈0.71. Three-hexagon states occur with probability ≈0.26, and hexagonal tessellations with more than three clusters form with probabilities of O(10^{-3}) or less. Spanning stripe states-where the domain walls run along one of the three lattice directions-appear with probability ≈0.03. "Blinker" configurations, which contain perpetually flippable spins, also emerge, but with a probability that is vanishingly small with the system size.