Comparing three spaceborne optical sensors via fine scale pixel based urban land cover classification products

Accessibility to higher resolution earth observation satellites suggests an improvement in the potential for fine scale image classification. In this comparative study, imagery from three optical satellites (WorldView-2, Pléiades and RapidEye) were used to extract primary land cover classes from a pixel-based classification principle in a suburban area. Following a systematic working procedure, manual segmentation and vegetation indices were applied to generate smaller subsets to in turn develop sets of ISODATA unsupervised classification maps. With the focus on the land cover classification differences detected between the sensors at spectral level, the validation of accuracies and their relevance for fine scale classification in the built-up environment domain were examined. If an overview of an urban area is required, RapidEye will provide an above average (0.69 κ) result with the built-up class sufficiently extracted. The higher resolution sensors such as WorldView-2 and Pléiades in comparison delivered finer scale accuracy at pixel and parcel level with high correlation and accuracy levels (0.65-0.71 κ) achieved from these two independent classifications.http://www.sajg.org.zaam201

The use of molecular markers for cervical screening of women living with HIV in South Africa

OBJECTIVE : To determine the performance of molecular screening strategies for detection of cervical intraepithelial neoplasia grade 3 or worse (CIN3+) in comparison with cytology screening in women living with HIV. DESIGN : Post-hoc analysis using data from a South African study cohort. METHODS : Cytology and human papillomavirus (HPV)-based strategies were evaluated, including single test and FAM19A4/miR124-2 methylation triage strategies. Participants underwent cytology screening and a colposcopy-directed biopsy. Valid results on cytology, HPV status, 16/18 genotyping and histology were available for 318 women. Detection of HPV and FAM19A4/miR124-2 hypermethylation was performed on DNA from cervical scrapes. Histological diagnosis of CIN3+ was used as outcome. RESULTS : Cytology provided highest specificity (91.6%), but lowest sensitivity (59.3%), whereas a single HPV test provided highest sensitivity (83.1%), but lowest specificity (66.4%). Combining cytology with methylation did not improve the performance compared with cytology alone: a slight increase in sensitivity was seen, at the cost of a decrease in specificity. Triage of high-risk HPV positive women with methylation increased specificity (76.1%) compared with a single HPV or cytology test, while maintaining acceptable sensitivity (72.9%). Similar performance was observed for HPV16/18 with methylation triage (sensitivity 79.7%, specificity 74.8%). The number of women needed to refer to detect one CIN3+ ranged from 1.5 (cytology) to 2.6 (single HPV test). CONCLUSION : Molecular screening strategies using HPV, with or without HPV16/18 genotyping, and FAM19A4/miR124-2 methylation have higher sensitivity with an acceptable loss in specificity compared with current cytology screening and are efficient for the detection of CIN3+ in South African women living with HIV.The VU University Research Fellowship (URF) program (Amsterdam, The Netherlands), the 1st For Women Foundation (Pretoria, South Africa), and the Carl & Emily Fuchs Foundation (Pretoria, South Africa).http://journals.lww.com/aidsonlinehj2020Medical VirologyObstetrics and Gynaecolog

Post-treatment monitoring by ASCL1/LHX8 methylation analysis in women with HIV treated for cervical intraepithelial neoplasia grade 2/3

Objective:Women with HIV (WWH) have an increased risk to develop recurrent cervical intraepithelial neoplasia grade 2/3 (rCIN2/3) after treatment compared with HIV-negative women. Therefore, appropriate posttreatment monitoring of WWH is important. This study evaluates the performance of ASCL1 and LHX8 methylation analysis as posttreatment monitoring test in WWH treated for CIN2/3, as alternative to cytology or human papillomavirus (HPV) as follow-up test.Design:Prospective observational cohort study.Methods:WWH treated for CIN2/3 by large loop excision of the transformation zone (LLETZ) (n = 61) were invited for follow-up study visits at 1, 2.5 and 4 years after baseline. Baseline and follow-up cervical scrapes were tested for cytology, HPV and DNA methylation of ASCL1 and LHX8 genes. The performance of these strategies for the detection of rCIN2/3 was evaluated in the first follow-up cervical scrape.Results:Thirteen (21.3%) rCIN2/3 lesions were detected within 4 years of follow-up. In women without rCIN2/3 in follow-up, methylation levels of ASCL1 and LHX8 decreased significantly after LLETZ treatment (P = 0.02 and 0.007, respectively). In women with rCIN2/3, methylation levels remained high after LLETZ treatment. The 4-year rCIN2/3 risk was 4.9% (95% CI: 0.6-16.5) for ASCL1/LHX8-negative women, 8.1% (95% CI: 1.7-21.9) for HPV-negative women and 7.7% (95% CI: 2.1-18.5) for cytology-negative women.Conclusion:A negative ASCL1/LHX8 methylation test in follow-up is associated with a low rCIN2/3 risk and could serve as an objective test of cure and well tolerated alternative for HPV and/or cytology screening in the posttreatment monitoring of WWH

Selection of women at risk for cervical cancer in an HIV-infected South African population

Objective: Cervical cancer is the leading cause of cancer-related death in women in South Africa. This study evaluates DNA methylation levels in cervical (pre)cancer and aims to assess the value of high-risk human papillomavirus (hrHPV) testing and methylation analysis, alone or in combination, on physician-taken cervical scrapes to detect cervical cancer, and cervical intraepithelial neoplasia grade 3 (CIN3) in an HIV-infected South African population. Design: Prospective observational multicentre cohort study. Methods: Women from a cohort of women living with HIV (n==355) and a referral cohort (n==109, 60% HIV seropositive) were included. Cervical scrapes were collected for hrHPV testing and methylation analysis of cell adhesion molecule 1, T-lymphocyte maturation-associated protein, and microRNA124-2 genes. Histologic endpoints were available for all participants. Performance for detection of CIN3 or worse (CIN3+) was determined in the cohort of women living with HIV and different testing strategies were compared. Results: HrHPV and methylation positivity rates increased with severity of cervical disease in the two study cohorts, each reaching 100% in samples of women with carcinoma. HrHPV testing showed a sensitivity for CIN3+ of 83.6%, at a specificity of 67.7%. Methylation analysis showed a comparable CIN3+ sensitivity of 85.2%, but a significantly lower specificity of 49.6%. HrHPV testing with reflex methylation analysis showed a CIN3+ sensitivity of 73.8%, at a specificity of 81.5%. Conclusion: In this HIV-infected South African population, stratifying hrHPV-positive women with reflex methylation analysis detects all cervical carcinomas and yields an acceptable sensitivity and specificity for CIN3+