18 research outputs found
Sonographic correlation of thyroid nodules with ultrasound aided fine needle non aspiration cytology
Objectives: To describe the sonographic patterns of thyroid nodules in patients undergoing thyroid ultrasound, to correlate sonographic characteristics of thyroid nodules to ultrasound aided fine needle non aspiration(US-FNNA) cytology and to determine the sensitivity and specificity of Ultrasound in characterising thyroid nodules.Design: Cross sectional study.Setting: The department of Radiology at Mulago Teaching and National Referral Hospital in Kampala Uganda. The Hospital is a 1,500-bed unit providing tertiary diagnostic, curative, rehabilitative, preventive and teaching services. Patients were recruited from both Medical and Surgical outpatient thyroid clinics.Subjects: All patients with thyroid nodules > 5 mm and who consented to have US aided-FNNA were enrolled consecutively.Results: One hundred and eighty one (181) participants were enrolled and final diagnoses were concluded in 177 of the participants (analysed) while four participants were excluded due to inadequate samples. The participants' age range was 19 to 83 years (mean age - 42 years ) and 93% were females. Five percent (n=9) were malignant, 18% suspiscious (n=34) and benign (n=134). The sonographic characteristics that were significantly correlated with final cytology diagnosis were a taller than wide AP diameter, micro-calcifications, heterogeneous and hypoechoic echo-patterns. Heterogeneous, hypoechoic and central vascularity had the highest sensitivity while wider than tall, anteroposterior diameter, no lymphadenopathy, and macro/no calcifications had the highest specificity.Conclusion: Sonographic features of micro-calcifications, taller than wide AP diameter, central vascularity and hypoechogenicity warrant US-FNNA. A bigger study correlating thyroid sonography with histological diagnosis is recommended
Generalisability of deep learning models in low-resource imaging settings: A fetal ultrasound study in 5 African countries
Most artificial intelligence (AI) research have concentrated in high-income
countries, where imaging data, IT infrastructures and clinical expertise are
plentiful. However, slower progress has been made in limited-resource
environments where medical imaging is needed. For example, in Sub-Saharan
Africa the rate of perinatal mortality is very high due to limited access to
antenatal screening. In these countries, AI models could be implemented to help
clinicians acquire fetal ultrasound planes for diagnosis of fetal
abnormalities. So far, deep learning models have been proposed to identify
standard fetal planes, but there is no evidence of their ability to generalise
in centres with limited access to high-end ultrasound equipment and data. This
work investigates different strategies to reduce the domain-shift effect for a
fetal plane classification model trained on a high-resource clinical centre and
transferred to a new low-resource centre. To that end, a classifier trained
with 1,792 patients from Spain is first evaluated on a new centre in Denmark in
optimal conditions with 1,008 patients and is later optimised to reach the same
performance in five African centres (Egypt, Algeria, Uganda, Ghana and Malawi)
with 25 patients each. The results show that a transfer learning approach can
be a solution to integrate small-size African samples with existing large-scale
databases in developed countries. In particular, the model can be re-aligned
and optimised to boost the performance on African populations by increasing the
recall to and at the same time maintaining a high precision
across centres. This framework shows promise for building new AI models
generalisable across clinical centres with limited data acquired in challenging
and heterogeneous conditions and calls for further research to develop new
solutions for usability of AI in countries with less resources
Evaluation of the Xpert MTB/RIF test for the diagnosis of childhood pulmonary tuberculosis in Uganda: a cross-sectional diagnostic study
Development of a Unifying Target and Consensus Indicators for Global Surgical Systems Strengthening: Proposed by the Global Alliance for Surgery, Obstetric, Trauma, and Anaesthesia Care (The G4 Alliance)
After decades on the margins of primary health care, surgical and anaesthesia care is gaining increasing priority within the global development arena. The 2015 publications of the Disease Control Priorities third edition on Essential Surgery and the Lancet Commission on Global Surgery created a compelling evidenced-based argument for the fundamental role of surgery and anaesthesia within cost-effective health systems strengthening global strategy. The launch of the Global Alliance for Surgical, Obstetric, Trauma, and Anaesthesia Care in 2015 has further coordinated efforts to build priority for surgical care and anaesthesia. These combined efforts culminated in the approval of a World Health Assembly resolution recognizing the role of surgical care and anaesthesia as part of universal health coverage. Momentum gained from these milestones highlights the need to identify consensus goals, targets and indicators to guide policy implementation and track progress at the national level. Through an open consultative process that incorporated input from stakeholders from around the globe, a global target calling for safe surgical and anaesthesia care for 80% of the world by 2030 was proposed. In order to achieve this target, we also propose 15 consensus indicators that build on existing surgical systems metrics and expand the ability to prioritize surgical systems strengthening around the world
Development and validation of quantitative PCR assays for HIV-associated cryptococcal meningitis in sub-Saharan Africa: a diagnostic accuracy study
Background:
HIV-associated cryptococcal meningitis is the second leading cause of AIDS-related deaths, with a 10-week mortality rate of 25–30%. Fungal load assessed by colony-forming unit (CFU) counts is used as a prognostic marker and to monitor response to treatment in research studies. PCR-based assessment of fungal load could be quicker and less labour-intensive. We sought to design, optimise, and validate quantitative PCR (qPCR) assays for the detection, identification, and quantification of Cryptococcus infections in patients with cryptococcal meningitis in sub-Saharan Africa.
Methods:
We developed and validated species-specific qPCR assays based on DNA amplification of QSP1 (QSP1A specific to Cryptococcus neoformans, QSP1B/C specific to Cryptococcus deneoformans, and QSP1D specific to Cryptococcus gattii species) and a pan-Cryptococcus assay based on a multicopy 28S rRNA gene. This was a longitudinal study that validated the designed assays on cerebrospinal fluid (CSF) of 209 patients with cryptococcal meningitis at baseline (day 0) and during anti-fungal therapy (day 7 and day 14), from the AMBITION-cm trial in Botswana and Malawi (2018–21). Eligible patients were aged 18 years or older and presenting with a first case of cryptococcal meningitis.
Findings:
When compared with quantitative cryptococcal culture as the reference, the sensitivity of the 28S rRNA was 98·2% (95% CI 95·1–99·5) and of the QSP1 assay was 90·4% (85·2–94·0) in CSF at day 0. Quantification of the fungal load with QSP1 and 28S rRNA qPCR correlated with quantitative cryptococcal culture (R2=0·73 and R2=0·78, respectively). Both Botswana and Malawi had a predominant C neoformans prevalence of 67% (95% CI 55–75) and 68% (57–73), respectively, and lower C gattii rates of 21% (14–31) and 8% (4–14), respectively. We identified ten patients that, after 14 days of treatment, harboured viable but non-culturable yeasts based on QSP1 RNA detection (without any positive CFU in CSF culture).
Interpretation:
QSP1 and 28S rRNA assays are useful in identifying Cryptococcus species. qPCR results correlate well with baseline quantitative cryptococcal culture and show a similar decline in fungal load during induction therapy. These assays could be a faster alternative to quantitative cryptococcal culture to determine fungal load clearance. The clinical implications of the possible detection of viable but non-culturable cells in CSF during induction therapy remain unclear.
Funding:
European and Developing Countries Clinical Trials Partnership; Swedish International Development Cooperation Agency; Wellcome Trust/UK Medical Research Council/UKAID Joint Global Health Trials; and UK National Institute for Health Research
Development and validation of quantitative PCR assays for HIV-associated cryptococcal meningitis in sub-Saharan Africa: a diagnostic accuracy study
Background: HIV-associated cryptococcal meningitis is the second leading cause of AIDS-related deaths, with a 10-week mortality rate of 25–30%. Fungal load assessed by colony-forming unit (CFU) counts is used as a prognostic marker and to monitor response to treatment in research studies. PCR-based assessment of fungal load could be quicker and less labour-intensive. We sought to design, optimise, and validate quantitative PCR (qPCR) assays for the detection, identification, and quantification of Cryptococcus infections in patients with cryptococcal meningitis in sub-Saharan Africa.
Methods:
We developed and validated species-specific qPCR assays based on DNA amplification of QSP1 (QSP1A specific to Cryptococcus neoformans, QSP1B/C specific to Cryptococcus deneoformans, and QSP1D specific to Cryptococcus gattii species) and a pan-Cryptococcus assay based on a multicopy 28S rRNA gene. This was a longitudinal study that validated the designed assays on cerebrospinal fluid (CSF) of 209 patients with cryptococcal meningitis at baseline (day 0) and during anti-fungal therapy (day 7 and day 14), from the AMBITION-cm trial in Botswana and Malawi (2018–21). Eligible patients were aged 18 years or older and presenting with a first case of cryptococcal meningitis.
Findings:
When compared with quantitative cryptococcal culture as the reference, the sensitivity of the 28S rRNA was 98·2% (95% CI 95·1–99·5) and of the QSP1 assay was 90·4% (85·2–94·0) in CSF at day 0. Quantification of the fungal load with QSP1 and 28S rRNA qPCR correlated with quantitative cryptococcal culture (R2=0·73 and R2=0·78, respectively). Both Botswana and Malawi had a predominant C neoformans prevalence of 67% (95% CI 55–75) and 68% (57–73), respectively, and lower C gattii rates of 21% (14–31) and 8% (4–14), respectively. We identified ten patients that, after 14 days of treatment, harboured viable but non-culturable yeasts based on QSP1 RNA detection (without any positive CFU in CSF culture).
Interpretation:
QSP1 and 28S rRNA assays are useful in identifying Cryptococcus species. qPCR results correlate well with baseline quantitative cryptococcal culture and show a similar decline in fungal load during induction therapy. These assays could be a faster alternative to quantitative cryptococcal culture to determine fungal load clearance. The clinical implications of the possible detection of viable but non-culturable cells in CSF during induction therapy remain unclear
Development of a Unifying Target and Consensus Indicators for Global Surgical Systems Strengthening: Proposed by the Global Alliance for Surgery, Obstetric, Trauma, and Anaesthesia Care (The G4 Alliance)
Coping with TB immune reconstitution inflammatory syndrome
The TB immune reconstitution inflammatory syndrome (IRIS) is a relatively frequent complication in HIV–TB-coinfected patients after they start highly active antiretroviral therapy (HAART). There are two forms of TB IRIS: the ‘paradoxical’ type (clinical worsening of a patient on TB treatment) and the ‘unmasking’ type (undiagnosed TB becoming apparent after starting HAART). Their pathogeneses are not fully understood, although, as the name suggests, IRIS following initiation of HAART is accompanied by an increase in immune responses to Mycobacterium tuberculosis. The diagnosis of TB IRIS is mainly clinical; so far there are no laboratory tests able to diagnose or predict TB IRIS. Risk factors for TB IRIS include a low CD4+ lymphocyte count, disseminated TB infection at HAART initiation and a short interval between TB treatment and HAART initiation. TB IRIS complicates the treatment and care for HIV–TB-coinfected patients. In this paper, we discuss some aspects of pathogenesis and options for the treatment and prevention of TB IRIS
The prevalence and clinical course of HIV-associated pulmonary cryptococcosis in Uganda
BACKGROUND: The prevalence and clinical course of pulmonary cryptococcosis in Sub-Saharan Africa are not well-described. METHODS: Consecutive HIV-infected adults hospitalized at Mulago Hospital (Kampala, Uganda) between September 2007 and July 2008 with cough ≥ 2 weeks were enrolled. Patients with negative sputum smears for acid-fast bacilli were referred for bronchoscopy with bronchoalveolar lavage (BAL). BAL fluid was examined for mycobacteria, Pneumocystis jirovecii, and fungi. Patients were followed two and six months after hospital discharge. RESULTS: Of 407 patients enrolled, 132 (32%) underwent bronchoscopy. Of 132 BAL fungal cultures, 15 (11%) grew Cryptococcus neoformans. None of the patients were suspected to have pulmonary cryptococcosis on admission. The median CD4 count among those with pulmonary cryptococcosis was 23 cells/µL (IQR 7–51). Of 13 patients who completed six-month follow-up, four died and nine were improved, including five who had started antiretroviral therapy (ART) but had not received antifungal medication. CONCLUSIONS: Pulmonary cryptococcosis is common in HIV-infected TB suspects in Uganda. Early initiation of ART in those with isolated pulmonary infection may improve outcomes, even without anti-fungal therapy. This finding suggests that some HIV-infected patients with C. neoformans isolated from respiratory samples may have colonization or localized infection