Diagnostic Accuracy and Implementation Feasibility of AI-Assisted Blind Ultrasound Sweep (SPAQ E-con AI) for Antenatal Screening by Non-Specialist Health Workers in Rural Democratic Republic of the Congo
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 发起方
- 入组人数
- 3,000
- 试验地点
- 2
- 主要终点
- Gestational age mean absolute error (MAE), Trimester 2 (14-27 weeks)
研究概览
简要总结
FS2 evaluates the diagnostic accuracy and implementation feasibility of an AI-assisted blind-sweep obstetric ultrasound (SPAQ E-con AI), operated by trained non-specialist health workers, for antenatal screening in rural Democratic Republic of the Congo. Primary outcomes are gestational age mean absolute error (Trimester 2 and Trimester 3) with 95% confidence intervals and AI confidence calibration. The reference standard is manual measurement by a reference reader (early ultrasound first; manual BPD if unavailable; last menstrual period is not used). Planned enrollment is approximately 1,380: Batch 1 (closed, 80 enrolled) and Batch 2 (approximately 1,300), within an IRB-approved ceiling of 3,000. Early termination is permitted upon achievement of pre-specified analysis-plan thresholds. The study is a multi-center prospective Hybrid Type 1 Effectiveness-Implementation design and includes a pre-specified adaptive model-update (Batch 2 cut) plan following FDA PCCP and STARD-AI guidance.
详细描述
Study conduct is organised in Batches. Batch 1 (Centre de Sante CBCO, Kenge health zone, Kwango province) enrolled 80 participants, of whom 78 had complete datasets, and is closed. Batch 2 is planned at approximately 1,300 participants. The confirmatory analysis cut is approximately 130 to 160 cases acquired with a model frozen before collection, comprising a core set of 80 to 100, an early-gestation enrichment of 25 to 30, and an upper-gestational-age enrichment of 25 to 30. Enrolment may stop early once the pre-specified confidence-interval criteria for the two primary gestational-age outcomes are met. The registered enrolment ceiling of 3,000 is unchanged.
Sites are facilities of the Kenge health zone, Kwango province, within the perimeter already approved in the protocol (up to 6 facilities plus 2 to 5 village outreach sites).
Eligibility follows the protocol: pregnant women aged 18 years or older. Multiple pregnancies are eligible.
Two sub-cohorts address the bounds of the gestational-age range. The early sub-cohort (crown-rump length 7 to 84 mm, approximately under 14 weeks) draws on the same source population as Cohort B-2 and is recruited through community health worker (RECO) village outreach and neighbouring health facilities; it is reported descriptively. The upper-bound sub-cohort (35 weeks or more) is a separate validation subset, recruited in parallel and analysed separately; sensitivity and specificity are reported, and positive and negative predictive values are not reported because prevalence in this subset is artificial.
The registered Trimester 3 estimation window (28 to 36 weeks) is unchanged. In Batch 2, point estimates are reported for 28 to 34 weeks, and 35 to 36 weeks is handled as "to be confirmed / refer". This is an operational reporting restriction, not a change to the registered window.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Pregnant women aged 18 years or older
- •Identified at a participating facility routine ANC visit or RECO village outreach within the Kenge health zone catchment
- •Written informed consent obtained
排除标准
- •Emergency presentation
- •Duplicate re-registration of an already-enrolled woman
- •Lacking capacity to consent
- •Planned relocation outside Kwango province during the study period
- •Refusal of consent
研究组 & 干预措施
Cohort B-3 - Early gestation (CRL 7-84 mm) enriched
Early-gestation enrichment sub-cohort: crown-rump length 7-84 mm, approximately under 14 weeks of gestation. Drawn from the same source population as Cohort B-2 and recruited through community health worker (RECO) village outreach and neighbouring health facilities. Reported descriptively.
干预措施: SPAQ E-con AI blind-sweep ultrasound (Diagnostic Test)
Cohort B-4 - Upper gestational-age bound (>=35 weeks) validation subset
Validation subset at the upper bound of the gestational-age range (35 weeks of gestation or more), recruited in parallel with the main cohort and analysed separately. Sensitivity and specificity are reported. Positive and negative predictive values are not reported, because prevalence in this subset is artificial.
干预措施: SPAQ E-con AI blind-sweep ultrasound (Diagnostic Test)
Cohort A
Natural enrollment / Description: Consecutive ANC attendees (natural prevalence)
干预措施: SPAQ E-con AI blind-sweep ultrasound (Diagnostic Test)
Cohort B-1 Placenta/malpresentation enriched
Enriched validation subset for placenta praevia and fetal malpresentation
干预措施: SPAQ E-con AI blind-sweep ultrasound (Diagnostic Test)
Cohort B-2 - Trimester 1 (CRL/GS) enriched
Enriched trimester 1 cases for CRL/GS gestational age models
干预措施: SPAQ E-con AI blind-sweep ultrasound (Diagnostic Test)
结局指标
主要结局
Gestational age mean absolute error (MAE), Trimester 2 (14-27 weeks)
时间窗: Through study completion, up to 12 months
MAE in days vs reference standard, with 95% CI; target MAE ≤7 days and upper 95% CI ≤10 days
Gestational age mean absolute error (MAE), Trimester 3 (28-36 weeks)
时间窗: Through study completion, up to 12 months
MAE in days vs reference standard, with 95% CI; target MAE ≤10 days and upper 95% CI ≤14 days
AI confidence calibration - Expected Calibration Error (ECE)
时间窗: At Batch 1 closure, up to 8 weeks
Expected Calibration Error from the reliability diagram of AI confidence versus reference-standard agreement; target \<=0.05
AI confidence calibration - Brier score
时间窗: At Batch 1 closure, up to 8 weeks
Brier score of AI confidence versus reference-standard agreement; target \<=0.20
次要结局
- Trimester 1 gestational age MAE (CRL and GS models)(Through study completion, up to 12 months)
- Placenta praevia and fetal malpresentation sensitivity and specificity(Through study completion, up to 12 months)
- Inter-rater reliability of gestational age - Intraclass Correlation Coefficient (ICC)(During the inter-rater assessment window, up to 1 week)
- Inter-rater reliability of placenta praevia classification - Cohen's kappa(During the inter-rater assessment window, up to 1 week)
- Inter-rater reliability of fetal presentation classification - weighted kappa(During the inter-rater assessment window, up to 1 week)
- Acceptability - Acceptability of Intervention Measure (AIM) score(Through study completion, up to 12 months)
- Feasibility - ultrasound throughput (scans per device per day)(Through study completion, up to 12 months)
- Fidelity - protocol adherence rate (5-item checklist)(Through study completion, up to 12 months)
- Penetration - proportion of eligible women screened(Through study completion, up to 12 months)
- Sustainability - intention to continue use(At study completion, up to 12 months)