Characteristics and findings from studies comparing portable ultrasound devices against conventional ultrasound for assessing fetal characteristics and gestational age estimation
| Author | Year | Country | Study design | Sample size | Gestational age | Portable ultrasound device used | Comparator | Key findings | Review team assessment |
| Dougherty et al 24 | 2021 | USA | Quality assurance and improvement protocol | 113 pregnant women | 14–26 weeks | GE Logiq i | A diagnostic obstetric ultrasound scan performed with Voluson E8 system by a trained sonographer | For biometric measures and calculations of estimated gestational age, inter-reader reliability ranged from 0.79 to 0.85 for all parameters except femur length. Over 94% of the obstetric sweep protocol ultrasound ages were within 7 days of the corresponding gold-standard age | Study demonstrates validity for these measures |
| Galjaard et al 30 | 2014 | Belgium | Cohort study (prospective) | 51 pregnant women | ‘Third trimester’ (range not indicated) | GE VScan | Comparison to routine scan performed by an experienced ultrasonographer on a Voluson E730 Expert | Regarding fetal growth measurements, there was very good agreement for measurements of biparietal diameter (BPD) and good agreement for femur length (FL) and trans-cerebellar diameter (TCD) | Study demonstrates validity for these measures |
| Haragan et al 31 | 2015 | USA | Diagnostic accuracy study | 251 pregnant women | 24–40 weeks | GE VScan | Formal growth ultrasound by registered diagnostic medical sonographers (device not specified) | Authors found a highly significant correlation between handheld and formal ultrasound measurements of abdominal circumference (R=0.939; p<0.001). Handheld ultrasound was also found to be viable for screening for Fetal Growth Restriction and Large for Gestational Age | Study demonstrates validity for these measures |
| Lausin et al 44 | 2009 | Croatia | Diagnostic accuracy study | 100 pregnant women | 16–41 weeks | Siemens Accuson 10 | Larger, traditional ultrasound devices used at the studies clinic (devices not specified) | Portable ultrasound device was found to be effective for measuring the following: quantity of amniotic fluid, position of the placenta, position of the fetus and fetal heartbeat. Regarding biometrical measurements, BPD was determined in 97% of patients, FL in 73% and AC in only 67%. | Study demonstrates validity for some measures, but not for others |
| Maraci et al 21 | 2020 | UK | Proof-of-concept evaluation | 1 pregnant woman | Not indicated | Konted Gen 1 C10R | 1)Sonographer performed manual estimation of TCD on scan; and 2) clinical hospital scan TCD measurement on the same subject made using a high-end ultrasound machine (GE Voluson E8) | TCD automated measurement (26.2 mm) was an underestimation compared with manual measurement (34.9 mm) and the hospital measurement (36.2 mm). It is not known whether this is a fault of the scan being from a portable device, or from the automated system itself. | Study did not demonstrate validity of a machine learning algorithm for TCD measurement, though sample size is small (n=1) |
| Saul et al 71 | 2012 | USA | Cross-sectional study | 68 pregnant women | ‘First trimester’ (range not indicated) | SonoSite Titan | Gestational age estimated by ultrasound performed in the department of radiology (device not specified) | Excluding cases with no fetal pole, the median discrepancy between emergency-physician performed and radiology department gestational age estimation was 2 days. The correlation coefficient was 0.978 | Study demonstrates validity for these measures |
| Sayasneh et al 34 | 2012 | UK | Cohort study (prospective) | 204 women | Group 1: ‘early pregnancy’ (range not indicated) Group 2: >14 weeks Group 3: Not applicable | GE VScan | Transvaginal and/or transabdominal examination depending on the clinical indication, using a Voluson E8 Expert | In group 1, there was good to very good agreement or identifying presence or absence of embryo, gestational sac, fetal heart motion, pregnancy location and final diagnostic outcome. In group 2, there was good to very good agreement for fetal presentation, placental location, and placental position. In group 3, there was very good agreement for final diagnosis and type of ovarian mass. For continuous variables, there was close agreement for CRL, mean sac diameter, FL and mean diameter of an ovarian mass | Study demonstrates validity for these measures |
| Shah et al 61 | 2010 | USA | Cross-sectional study | 96 ultrasound examinations on 38 pregnant women | 14–40 weeks | SonoSite M-Turbo | Formal sonography by an ultrasound technician using Accuvix XQ ultrasound machine | When comparing physician-performed measurements with true gestational age measurements, BPD had a correlation coefficient of 0.947 and FL had a correlation coefficient of 0.957. Physician’s determination of fetal viability had an overall accuracy of 96% when using ultrasound | Study demonstrates validity for these measures |
| Toscano et al 38 | 2021 | Peru | Single-centre pilot study | 126 pregnant women | ‘Second or third trimester’ (range not indicated) | Mindray DP-10 | Concurrently performed standard of care ultrasound obtained and interpreted by an experienced ultrasonographer | Telediagnostic system with ultrasound protocol showed excellent agreement with standard of care ultrasound allowing identification of number of fetuses, fetal presentation, placental location and assessment of amniotic fluid volume. Intraclass correlation was good or excellent for all fetal biometric measurements—including kappa coefficient of 0.95 for estimated gestational age | Study demonstrates validity for these measures |
| Troyano et al 35 | 2013 | Spain | Pilot study | 80 women | 11–13 weeks | GE VScan | The same measurements performed with a traditional US device (Voluson 730 Expert) | When comparing to the conventional ultrasound findings, there was high Pearson’s correlation coefficient for BPD, gynaecological measurements and overall correlation | Study demonstrates validity for these measures |