Obstetric ultrasound: How, why and when

The purpose of this review is to summarize the most recently published literature regarding ultrasound (US) use in limited-resource settings. The body of literature is quite heterogeneous, but several recurring themes emerged from the data. Research regarding education is burgeoning, with studies showing that low-cost training modules can effectively teach US skills to novices. Many studies reported feasibility of training non-physicians to perform US, which allows for task-shifting. Research regarding clinical application of US is broad; especially regarding Echocardiography, Infectious Disease, and OB-GYN. US continues to be a highly utilized tool in limited-resource settings. We identified several common themes among the recent literature: the use of educational interventions to train non-physician providers, the use of US for improved screening methods, and the expanded role of US in clinical purposes including Infectious Disease, Echocardiography, Pulmonary, and Obstetrics.

Ultrasound in the Limited-Resource Setting: A Systematic Qualitative Review

The aim of this study was to determine the quality of fetal biometry and pulsed‐wave Doppler ultrasound measurements in a prospective cohort study in Uganda.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/uog.26051

Standardization and quality control of Doppler and fetal biometric ultrasound measurements in low‐income setting

Ultrasonography is essential in the prenatal diagnosis and care for the pregnant mothers. However, the measurements obtained often contain a small percentage of unavoidable error that may have serious clinical implications if substantial. We therefore evaluated the level of intra and inter-observer error in measuring mean sac diameter (MSD) and crown-rump length (CRL) in women between 6 and 10 weeks’ gestation at Mulago hospital. This was a cross-sectional study conducted from January to March 2016. We enrolled 56 women with an intrauterine single viable embryo. The women were scanned using a transvaginal (TVS) technique by two observers who were blinded of each other’s measurements. Each observer measured the CRL twice and the MSD once for each woman. Intra-class correlation coefficients (ICCs), 95% limits of agreement (LOA) and technical error of measurement (TEM) were used for analysis. Intra-observer ICCs for CRL measurements were 0.995 and 0.993 while inter-observer ICCs were 0.988 for CRL and 0.955 for MSD measurements. Intra-observer 95% LOA for CRL were ± 2.04 mm and ± 1.66 mm. Inter-observer LOA were ± 2.35 mm for CRL and ± 4.87 mm for MSD. The intra-observer relative TEM for CRL were 4.62% and 3.70% whereas inter-observer relative TEM were 5.88% and 5.93% for CRL and MSD respectively. Intra- and inter-observer error of CRL and MSD measurements among pregnant women at Mulago hospital were acceptable. This implies that at Mulago hospital, the error in pregnancy dating is within acceptable margins of ±3 days in first trimester, and the CRL and MSD cut offs of ≥7 mm and ≥ 25 mm respectively are fit for diagnosis of miscarriage on TVS. These findings should be extrapolated to the whole country with caution. Sonographers can achieve acceptable and comparable diagnostic accuracy levels of MSD and CLR measurements with proper training and adherence to practice guidelines.

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Emmanuel Lako Ernesto Loro

Papers

Measurement error of mean sac diameter and crown-rump length among pregnant women at Mulago hospital, Uganda