Next-generation monitoring in obstetrics: Assessing the accuracy of non-piezo portable ultrasound technology.

INTRODUCTION: The emergence of handheld ultrasound devices capable of connecting to cell phones or tablets heralds a significant advancement in medical technology, particularly within the field of obstetrics. These devices offer the promise of immediate bedside ultrasound examinations, potentially revolutionizing patient care by enabling fetal assessments in diverse settings. MATERIAL AND METHODS: This prospective study aimed to validate the reliability of non-piezo, chip-based handheld ultrasound devices in clinical obstetric practice. Conducted in a university hospital obstetric ward, the study included 100 pregnant women between 17 and 41 weeks of gestation. Participants underwent ultrasound examinations using both conventional and portable point-of-care ultrasound (POCUS) devices to compare the accuracy in estimating fetal weight and other parameters, such as cardiac activity, fetal presentation, placental location, and amniotic fluid volume. The reliability and agreement between the devices were assessed using intraclass correlation coefficients, Bland-Altman plots, and Pearson correlation coefficients. RESULTS: The results show a near-perfect agreement (0.98) and correlation (r = 0.98, p < 0.001) for estimated fetal weight and most biometry measurements between the two types of ultrasound devices, with slight deviations in head circumference and amniotic fluid index measurements. Subgroup analysis revealed variations in agreement and correlation rates with higher BMI and advanced gestational age, indicating areas for further refinement. CONCLUSIONS: These findings affirm the high reliability of handheld ultrasound devices for basic obstetric ultrasound evaluations, supporting their integration into daily clinical practice. This technology improves the flexibility and immediacy of prenatal care, although further research is needed to optimize its application across patient populations and treatment settings.

Diagnostic Accuracy of an Integrated AI Tool to Estimate Gestational Age From Blind Ultrasound Sweeps.

Importance: Accurate assessment of gestational age (GA) is essential to good pregnancy care but often requires ultrasonography, which may not be available in low-resource settings. This study developed a deep learning artificial intelligence (AI) model to estimate GA from blind ultrasonography sweeps and incorporated it into the software of a low-cost, battery-powered device. Objective: To evaluate GA estimation accuracy of an AI-enabled ultrasonography tool when used by novice users with no prior training in sonography. Design, Setting, and Participants: This prospective diagnostic accuracy study enrolled 400 individuals with viable, single, nonanomalous, first-trimester pregnancies in Lusaka, Zambia, and Chapel Hill, North Carolina. Credentialed sonographers established the "ground truth" GA via transvaginal crown-rump length measurement. At random follow-up visits throughout gestation, including a primary evaluation window from 14 0/7 weeks' to 27 6/7 weeks' gestation, novice users obtained blind sweeps of the maternal abdomen using the AI-enabled device (index test) and credentialed sonographers performed fetal biometry with a high-specification machine (study standard). Main Outcomes and Measures: The primary outcome was the mean absolute error (MAE) of the index test and study standard, which was calculated by comparing each method's estimate to the previously established GA and considered equivalent if the difference fell within a prespecified margin of ±2 days. Results: In the primary evaluation window, the AI-enabled device met criteria for equivalence to the study standard, with an MAE (SE) of 3.2 (0.1) days vs 3.0 (0.1) days (difference, 0.2 days [95% CI, -0.1 to 0.5]). Additionally, the percentage of assessments within 7 days of the ground truth GA was comparable (90.7% for the index test vs 92.5% for the study standard). Performance was consistent in prespecified subgroups, including the Zambia and North Carolina cohorts and those with high body mass index. Conclusions and Relevance: Between 14 and 27 weeks' gestation, novice users with no prior training in ultrasonography estimated GA as accurately with the low-cost, point-of-care AI tool as credentialed sonographers performing standard biometry on high-specification machines. These findings have immediate implications for obstetrical care in low-resource settings, advancing the World Health Organization goal of ultrasonography estimation of GA for all pregnant people. Trial Registration: ClinicalTrials.gov Identifier: NCT05433519.

Exploring a new paradigm for the fetal anomaly ultrasound scan: Artificial intelligence in real time.

OBJECTIVE: Advances in artificial intelligence (AI) have demonstrated potential to improve medical diagnosis. We piloted the end-to-end automation of the mid-trimester screening ultrasound scan using AI-enabled tools. METHODS: A prospective method comparison study was conducted. Participants had both standard and AI-assisted US scans performed. The AI tools automated image acquisition, biometric measurement, and report production. A feedback survey captured the sonographers' perceptions of scanning. RESULTS: Twenty-three subjects were studied. The average time saving per scan was 7.62 min (34.7%) with the AI-assisted method (p < 0.0001). There was no difference in reporting time. There were no clinically significant differences in biometric measurements between the two methods. The AI tools saved a satisfactory view in 93% of the cases (four core views only), and 73% for the full 13 views, compared to 98% for both using the manual scan. Survey responses suggest that the AI tools helped sonographers to concentrate on image interpretation by removing disruptive tasks. CONCLUSION: Separating freehand scanning from image capture and measurement resulted in a faster scan and altered workflow. Removing repetitive tasks may allow more attention to be directed identifying fetal malformation. Further work is required to improve the image plane detection algorithm for use in real time.

Experiences of midwives on Vscan limited obstetric ultrasound use: a qualitative exploratory study.

BACKGROUND: Ethiopia is a low-income country located in the horn of Africa's sub-Saharan region, with very high incidences of maternal and neonatal mortality. Quality antenatal care improves perinatal health outcomes. The USAID funded Transform: Primary Health Care Activity in collaboration with the Ministry of Health and GE Healthcare introduced Vscan limited obstetric ultrasound services in 120 health centers in Ethiopia. So far, the experiences and opinions of midwives on their use have not been explored and described within the local context. This study therefore aims to explore and describe the experiences and opinions of midwives on Vscan limited obstetric ultrasound services at health centers within Ethiopia. METHODS: An exploratory and descriptive qualitative study was conducted in Amhara, Oromia, and Southern Nations, Nationalities and Peoples' (SNNP) regions of Ethiopia. Twenty-four participants were selected through a purposeful sampling technique. In-depth individual interviews with trained midwives with practical hands-on limited obstetric ultrasound service provision experience were conducted. The thematic analysis was conducted manually. RESULTS: The qualitative data analysis on the experiences and opinions of midwives revealed three themes, namely: individual perception of self-efficacy, facilitators, and barriers of limited obstetric ultrasound services. The basic ultrasound training, which was unique in its organization and arrangement, prepared and built the self-efficacy of trainees in executing their expected competencies. Support of health systems and health managers in dedicating space, availing essential supplies, and assigning human resources emerged as facilitators of the initiated limited obstetric ultrasound services, whereas high workload on one or two ultrasound trained midwives, interruption of essential supplies like paper towels, gel, and alternative power sources were identified as barriers for limited ultrasound services. CONCLUSION: This study explored the experiences and opinions of midwives who were trained on the provision of limited obstetric ultrasound services and served the community in health centers in rural parts of Ethiopia. The results of this study revealed the positive impacts of the intervention on the perceived self-efficacy, facilitation, and breaking-down of barriers to obstetric ultrasound services. Before scaling-up limited obstetric ultrasound interventions, health managers should ensure and commit to availing essential supplies (e.g., paper towels, ultrasound gel, and large memory hard discs), arranging private rooms, and training other mid-level health professionals. In addition, improving pregnant women's literacy on the national schedule for ultrasound scanning services is recommended.

Society for Maternal-Fetal Medicine Special Statement: Reducing the risk of transmitting infection by transvaginal ultrasound examination.

Recent surveys have shown widespread lapses in the procedures used to reduce the risk of transmitting infection via medical devices. Transvaginal ultrasound examination has the potential to transmit vaginal infections, including human papillomavirus. Areas of particular concern are the use of probe covers with high rates of leakage, disinfectants that are not effective against human papillomavirus, and coupling gel from multiple-use containers. We reviewed these issues, and we recommend 4 steps to reduce the risk of transmitting infection. First, during every transvaginal ultrasound exam, the probe should be covered with a sterile, single-use "viral barrier" cover or a condom. Second, sterile, single-use ultrasound gel packets should be used. Third, after every examination, the probe should be cleaned to remove any visible gel or debris. Finally, after cleaning, the probe should undergo high-level disinfection using an agent with proven efficacy against the human papillomavirus, including hydrogen peroxide, hypochlorite, or peracetic acid. Glutaraldehyde, orthophthalaldehyde, phenols, and isopropyl alcohol have virtually no efficacy against the human papillomavirus.

Minimizing cross transmission of SARS-CoV-2 in obstetric ultrasound during COVID-19 pandemic.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated infection (COVID-19) is affecting populations worldwide. This statement may serve as guidance for infection prevention and safe ultrasound practices during the COVID-19 pandemic. Ultrasound examination is a fundamental part of obstetric care, yet it is a potential vector for transmission of SARS-CoV-2. Decontamination methods should always be implemented for ultrasound equipment, especially in the presence of suspected or confirmed COVID-19 cases. There must be workflow policies to protect pregnant women and healthcare providers from nosocomial cross transmission of SARS-CoV-2. Cleaning and disinfecting of equipment must be in accordance with their potential of pathogen transmission. Consider using telemedicine and genetic technologies as an adjunctive of obstetric ultrasound to reduce patient crowding. Patient triage and education of healthcare providers of infection prevention are crucial to minimize cross contamination of SARS-CoV-2 during obstetric ultrasound.

Impact of fetal brain ultrasound tutor smartphone application on normal anatomy learning.

OBJECTIVE: The "Fetal Brain Tutor 4us" (FBTApp) is a recently developed application for interactive multiplanar navigation through the normal fetal brain. The purpose of this work was to assess its impact on normal anatomy learning. METHODS: A multiple-choice quiz (MCQ) was administered to first-year resident doctors in Obstetrics and Gynecology in two separate sessions, before and 2 weeks after downloading the FBTApp. For each MCQ, the junior trainee was asked to use one out of five items to label a specific cerebral structure on an ultrasound image of a normal midtrimester fetal brain. Six sonographic images of the fetal brain on each of the three scanning planes (axial, sagittal, and coronal) were shown to the participants at either session. The results of the two sessions were analysed and compared. RESULTS: Overall, 216 questions were administered to the trainees in the 2-week study, 108 before and 108 after the use of the FBTApp. From the first to the second sessions, a significant increase of correct answers was noted (from 47/108 or 43% to 77/108 or 71%, P < 0.01). Particularly, a better improvement was obtained in the correct labelling of cerebral structures on the nonaxial (from 32% to 67%, +35%) vs axial (from 67% to 81%, +14%) view planes of the brain (P < 0.01). CONCLUSION: The use of FBTApp seems capable to improve the knowledge of the normal fetal brain anatomy in subjects naive to dedicated prenatal ultrasound. This improvement seems greater on nonaxial planes.

Comparison of automated vs. manual measurement to estimate fetal weight in isolated polyhydramnios.

Objective To understand the impact of the measurement method to predict actual birthweight in pregnancies complicated with isolated polyhydramnios in the third trimester. Methods A prospective study was conducted with 60 pregnant women between the 37th and 40th weeks of gestation. Routine biometric measurements were obtained by two-dimensional (2D) ultrasonography. When a satisfactory image was obtained, the image was frozen to get two measurements. First, calipers were placed to get the manual measurement. Then automated measurement was captured by the ultrasonography machine in the same image. The fetal weight was estimated by using the Hadlock II formula. Results The mean difference was found to be 0.03, -0.77, -0.02 and 0.17 for biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL), respectively. Pearson's correlation coefficient between automated and manual estimated fetal weights (EFWs) and the actual birthweight was 0.919 and 0.796, respectively. The mean difference between actual and manual EFW measurement values was 46.16 ± 363.81 g (range between -745 g and 685 g) (P = 0.330). Also, the mean difference between actual and automated EFW measurement values was found to be 31.98 ± 218.65 g (range between -378 g and 742 g) (P = 0.262). The Bland-Altman test results have shown that, 666 g lower or 759 g higher values were obtained when the measurement was performed manually. On the other hand, EFW results were 396 g lower or 460 g higher than the actual birthweight with automated measurement tools. Conclusion The accuracy rate of fetal weight estimation with ultrasonography is high for both automated and manual measurements. Automated tools have a higher success to predict the EFW.

Dynamic fetal cardiovascular magnetic resonance imaging using Doppler ultrasound gating.

BACKGROUND: Fetal cardiovascular magnetic resonance (CMR) imaging may provide a valuable adjunct to fetal echocardiography in the evaluation of congenital cardiovascular pathologies. However, dynamic fetal CMR is difficult due to the lack of direct in-utero cardiac gating. The aim of this study was to investigate the effectiveness of a newly developed Doppler ultrasound (DUS) device in humans for fetal CMR gating. METHODS: Fifteen fetuses (gestational age 30-39 weeks) were examined using 1.5 T CMR scanners at three different imaging sites. A newly developed CMR-compatible DUS device was used to generate gating signals from fetal cardiac motion. Gated dynamic balanced steady-state free precession images were acquired in 4-chamber and short-axis cardiac views. Gating signals during data acquisition were analyzed with respect to trigger variability and sensitivity. Image quality was assessed by measuring endocardial blurring (EB) and by image evaluation using a 4-point scale. Left ventricular (LV) volumetry was performed using the single-plane ellipsoid model. RESULTS: Gating signals from the fetal heart were detected with a variability of 26 ± 22 ms and a sensitivity of trigger detection of 96 ± 4%. EB was 2.9 ± 0.6 pixels (4-chamber) and 2.5 ± 0.1 pixels (short axis). Image quality scores were 3.6 ± 0.6 (overall), 3.4 ± 0.7 (mitral valve), 3.4 ± 0.7 (foramen ovale), 3.6 ± 0.7 (atrial septum), 3.7 ± 0.5 (papillary muscles), 3.8 ± 0.4 (differentiation myocardium/lumen), 3.7 ± 0.5 (differentiation myocardium/lung), and 3.9 ± 0.4 (systolic myocardial thickening). Inter-observer agreement for the scores was moderate to very good (kappa 0.57-0.84) for all structures. LV volumetry revealed mean values of 2.8 ± 1.2 ml (end-diastolic volume), 0.9 ± 0.4 ml (end systolic volume), 1.9 ± 0.8 ml (stroke volume), and 69.1 ± 8.4% (ejection fraction). CONCLUSION: High-quality dynamic fetal CMR was successfully performed using a newly developed DUS device for direct fetal cardiac gating. This technique has the potential to improve the utility of fetal CMR in the evaluation of congenital pathologies.

Reproducibility and acceptability of ultrasound measurements of head-perineum distance.

INTRODUCTION: We aimed to test the reproducibility of head-perineum distance (HPD) measurements using two different ultrasound devices and five examiners, to compare ultrasound measurements and clinical assessments and to study if ultrasound examinations were acceptable for women in labor. MATERIAL AND METHODS: A reproducibility study was performed at Lund University Hospital, Sweden and Landspitali University Hospital, Iceland from February 2015 to February 2017. The study population comprised 40 healthy women in labor. HPD was measured with three replicate measurements from each woman with two different ultrasound devices, and the measurements were compared with clinical assessments. Acceptability was tested with a visual analog scale (VAS), and the mean VAS score from both ultrasound devices was compared with the VAS score from clinical palpation. RESULTS: The median time interval between start of examinations with devices was 10 min (range 1-26 min). The intra-observer repeatability coefficient was 4.3 mm and the intraclass correlation coefficient was 0.97 (95% CI 0.95-0.98). The intraclass correlation coefficient between the two devices was 0.86 (95% CI 0.74-0.93) and limits of agreement were -9.6 mm to 16.6 mm. However, we observed a significant mean HPD difference between devices (3.5 mm; 95% CI 1.4-5.6 mm). Clinical assessments and the mean measurements of HPD were correlated (r = 0.64, p < 0.01). We found significant differences in acceptability in favor of ultrasound. The mean VAS score for both ultrasound devices was 2.0 vs. 4.1 for clinical examination (p < 0.01). CONCLUSION: We found excellent intra-observer repeatability, good correlation but significant difference between devices. Women reported less discomfort with ultrasound than with clinical examinations.

A Crossover Comparison of Standard and Telerobotic Approaches to Prenatal Sonography.

OBJECTIVES: To determine the feasibility of a telerobotic approach to remotely perform prenatal sonographic examinations. METHODS: Thirty participants were prospectively recruited. Participants underwent a limited examination (assessing biometry, placental location, and amniotic fluid; n = 20) or a detailed examination (biometry, placental location, amniotic fluid, and fetal anatomic survey; n = 10) performed with a conventional ultrasound system. This examination was followed by an equivalent examination performed with a telerobotic ultrasound system, which enabled sonographers to remotely control all ultrasound settings and fine movements of the ultrasound transducer from a distance. Telerobotic images were read independently from conventional images. RESULTS: The mean gestational age ± SD of the 30 participants was 22.9 ± 5.3 weeks. Paired-sample t tests showed no statistically significant difference between conventional and telerobotic measurements of fetal head circumference, biparietal diameter, or single deepest vertical pocket of amniotic fluid; however, a small but statistically significant difference was observed in measurements of abdominal circumference and femur length (P < .05). Intraclass correlations showed excellent agreement (>0.90) between telerobotic and conventional measurements of all 4 biometric parameters. Of 21 fetal structures included in the anatomic survey, 80% of the structures attempted across all patients were sufficiently visualized by the telerobotic system (range, 57%-100% per patient). Ninety-seven percent of patients strongly or somewhat agreed that they would be willing to have another telerobotic examination in the future. CONCLUSIONS: A telerobotic approach is feasible for remotely performing prenatal sonographic examinations. Telerobotic sonography (robotic telesonography) may allow for the development of satellite ultrasound clinics in rural, remote, or low-volume communities, thereby increasing access to prenatal imaging in underserved communities.

Measured acoustic intensities for clinical diagnostic ultrasound transducers and correlation with thermal index.

OBJECTIVES: To investigate if the thermal index for bone (TIB) displayed on screen is an adequate predictor for the derated spatial-peak temporal-average (ISPTA.3 ) and spatial-peak pulse-average (ISPPA.3 ) acoustic intensities in a selection of clinical diagnostic ultrasound machines and transducers. METHODS: We calibrated five clinical diagnostic ultrasound scanners and 10 transducers, using two-dimensional grayscale, color Doppler and pulsed-wave Doppler, both close to and far from the transducer, with a TIB between 0.1 and 4.0, recording 103 unique measurements. Acoustic measurements were performed in a bespoke three-axis computer-controlled scanning tank, using a 200-µm-diameter calibrated needle hydrophone. RESULTS: There was significant but poor correlation between the acoustic intensities and the on-screen TIB. At a TIB of 0.1, the ISPTA.3 range was 0.51-50.49 mW/cm2 and the ISPPA.3 range was 0.01-207.29 W/cm2 . At a TIB of 1.1, the ISPTA.3 range was 19.02-309.44 mW/cm2 and the ISPPA.3 range was 3.87-51.89 W/cm2 . CONCLUSIONS: TIB is a poor predictor for ISPTA.3 and ISPPA.3 and for the potential bioeffects of clinical diagnostic ultrasound scanners. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Cardiac output assessment in pregnancy: comparison of two automated monitors with echocardiography.

OBJECTIVE: To compare non-invasive hemodynamic measurements obtained in pregnant and postpartum women using two automated cardiac output monitors against those obtained by two-dimensional (2D) transthoracic echocardiography (TTE). METHODS: This was a cross-comparison study into which we recruited 114 healthy women, either with normal singleton pregnancy (across all three trimesters) or within 72 hours following delivery. Cardiac output estimations were obtained non-invasively using two different monitors, Ultrasound Cardiac Output Monitor (USCOM®, which uses continuous-wave Doppler analysis of transaortic blood flow) and Non-Invasive Cardiac Output Monitor (NICOM®, which uses thoracic bioreactance), and 2D-TTE. The performance of each monitor was assessed relative to that of TTE by calculating bias, precision, 95% limits of agreement and mean percentage difference (MPD). Intraobserver repeatability was assessed for both monitors and interobserver reproducibility was assessed for USCOM, NICOM being operator-independent. RESULTS: Following exclusions due to poor-quality results of a monitor or TTE, or for medical reasons, our analysis included 98 women (29 in the first trimester, 25 in the second and 21 in the third, and 23 postpartum). For cardiac output estimation, when compared with TTE, USCOM had a bias ranging from 0.4 to 0.9 L/min. The MPD of USCOM was 29% in the third-trimester cohort. NICOM had a bias ranging from -1.0 to 0.6 L/min, with a MPD of 32% in the third-trimester group. There was limited agreement between the cardiac output monitors and TTE in the first and second trimesters, with a MPD of 38% for USCOM in both first and second trimesters, and 71% and 61% for NICOM in first and second trimesters, respectively. For cardiac output estimation using USCOM, we found excellent intraobserver repeatability (intraclass correlation coefficient (ICC), 0.97; 95% CI, 0.95-0.98) and interobserver reproducibility (ICC, 0.90; 95% CI, 0.81-0.94), and the repeatability for NICOM was comparable (ICC, 0.95; 95% CI, 0.93-0.97). CONCLUSIONS: We found good agreement of both USCOM and NICOM when compared with 2D-TTE, specifically in the third trimester of pregnancy. Both devices had good intraobserver repeatability and either had good interobserver reproducibility or were operator-independent. Future studies should take into account the significant differences in the precise maternal hemodynamic values obtained by these devices, and consider developing device-specific reference ranges in pregnancy and the postpartum period. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

The Effect of the Pressure Exerted on the Maternal Abdominal Wall by the US Probe on Fetal MCA Peak Systolic Velocity.

Purpose To quantify the pressure exerted on the maternal abdominal wall during ultrasound examination and evaluate its effect on the fetal middle cerebral artery (MCA) peak systolic velocity (PSV). Materials and Method Gravid women with singleton pregnancies in their 2nd-3 rd trimester undergoing fetal sonographic evaluation for various indications were recruited. Each subject underwent transabdominal US measuring fetal distance from the probe, abdominal thickness, amniotic fluid index and biophysical profile. The applied pressure was measured simultaneously using an electronic pressure sensor attached directly to the US probe. For each subject baseline values of the pressure required for proper visualization were obtained. Fetal MCA was then demonstrated using color Doppler US. The PSV was measured at different pressure ranges with each subject used as her own control. Care was taken not to exceed the baseline pressure for each subject. Results 29 women were recruited. 24 subjects (82.7 %) demonstrated a statistically significant positive correlation between the pressure exerted and MCA-PSV (R-0.37, p < 0.0001). Of these, 4 subjects (13.8 % of study population) demonstrated elevation of PSV values above 1.29 MOM and 5 subjects (17.2 %) demonstrated elevation of PSV values above 1.5 MOM for gestational age with increasing pressure. In total, 9 subjects (31 %) demonstrated significant changes in the MCA-PSV measurements (owing to increase in pressure applied) that could potentially falsely influence clinical obstetric diagnosis and management. Conclusion The pressure exerted on the maternal abdominal wall during US examination is an important parameter, producing clinically significant measurable changes in fetal MCA hemodynamics. Further study is needed in order to demonstrate the potential effect of pressure as a parameter influencing the diagnostic accuracy of the MCA-PSV in the setting of fetal anemia.

Novel Application of Laparoscopic Ultrasound for Fetoscopic Laser Ablation in Twin-Twin Transfusion Syndrome with Complete Anterior Placenta.

Fetoscopic laser coagulation of the placental communicating vessels has become the standard treatment for monochorionic/diamniotic twin pregnancies complicated by severe twin-twin transfusion syndrome. Fetoscopic trocar placement can be performed with transabdominal ultrasound guidance with a posterior placenta and most anterior placentas that have a safe avascular window for entry. However, trocar insertion is challenging in cases of a complete anterior placenta without an avascular window. Current techniques to deal with this situation include mini-laparotomy with exteriorization to allow for dorsal entry, percutaneous lateral entry under transabdominal ultrasound/Doppler guidance, and laparoscopic assisted access with direct visualization of trocar entry. We describe a modified technique of laparoscopic assisted fetoscopic trocar placement using a laparoscopic ultrasound probe, which allows for precise, real-time guidance of trocar placement.

High-frequency linear transducer improves detection of an intrauterine pregnancy in first-trimester ultrasonography.

OBJECTIVE: The objective was to determine if the need for transvaginal ultrasonographic examination can be decreased by the addition of the transabdominal high-frequency, 12-4-MHz linear transducer after a failed examination with the 6-2-mHz curvilinear transducer when evaluating for an intrauterine pregnancy (IUP). METHODS: This is a prospective pilot study of women in their first trimester of pregnancy presenting to the emergency department with abdominal pain and/or vaginal bleeding. If no IUP was identified using the curvilinear transducer via the transabdominal approach, they were subsequently scanned using the linear transducer. Patients without evidence of an IUP transabdominally were scanned via the transvaginal approach. RESULTS: Eighty-one patients were evaluated; no IUP was visualized in 27 using the standard curvilinear transducer approach, and these then had an ultrasonography performed with the linear transducer. Of these, 9 patients (33.3%; 0.95 confidence interval [CO], 15.5%-51.1%) were found to have an IUP with the linear transducer. For the 18 patients who received a transvaginal scan, 15 patients (83.3%; 0.95 CI, 66.1%-100%) had no IUP identified with the transvaginal transducer, and 3 (16.7%; 0.95 CI, 0%-33.9%) had an IUP identified. CONCLUSIONS: The transabdominal use of a high-frequency linear transducer in the evaluation of patients in the first trimester after failed curvilinear transducer results in a clinically significant reduction in the need for transvaginal ultrasonography to confirm the presence of an IUP.

Invention of ultrasonic Doppler fetal actocardiograph and continuous recording of fetal movements.

AIMS: To enable scientific studies on fetal movements and its relation to fetal heart rate directly detecting fetal chest motion with ultrasonic Doppler method. METHODS: A prototype of an ultrasonic Doppler fetal actocardiograph (ACG) was designed and handmade by the author. A 2 MHz ultrasound fetal heart rate (FHR) monitor was remodeled to detect fetal heartbeat and chest movement Doppler signals with a single ultrasound probe. The fetal movement Doppler signal was 20-50 Hz using 2 MHz ultrasound, separated from the fetal heartbeat Doppler signal, which was 100 or more Hz and sent to the autocorrelation FHR meter to record FHR curve, while fetal movement Doppler signals were detected through 20-80 Hz band-pass filter, and changed to spikes recorded on a cardiotocography chart. RESULTS: The spike amplitudes of a moving steel ball expressed fetal movement on the ACG. FHR acceleration synchronized with fetal movement bursts. Fetal resting and active states are separated using the ACG. Fetal hiccupping movements on ACG were regular continuous spikes with 2-3 s intervals. CONCLUSION: Fetal movements and hiccups were correctly recorded with the FHR curve. The relation of FHR and movement will be further clarified in future ACG readings.

Is Transducer Hygiene sufficient when Vaginal Probes are used in the Clinical Routine?

Vaginal ultrasound probes are semi-critical Group A medical products which must be disinfected following the manufacturer's instructions after every patient examination. According to the "Essential Requirements for Medical Devices (Directive 93/42/EEC, Annex I, paragraph 13)" the manufacturer's instructions for use for reusable products must contain suitable instructions for preparation processes. This presumes both an effective and material-compatible method. Evidence of effectiveness must be validated.In the Editorial in issue 1 Ultraschall in der Medizin/European Journal of Ultrasound 2005 we discussed the topic of transducer hygiene and stated that proper handling and cleaning as well as disinfection of probes in daily use are indispensable. This applies particularly to vaginal ultrasound probes routinely used in gynecological and obstetrical clinics, gynecological practices as well as IVF centers Normally the probe used in a transvaginal ultrasound examination is covered with a latex protective cover (with CE marking) which contains a certain amount of ultrasound gel. After the examination, the cover is removed and disposed of, and the gel is removed from the transducer. Since handling of the probe, ultrasound gel and cover can result in smear infections and cross-contamination with various pathogens (e. g. MRSA, HBV, HCV, HIV, herpes papilloma and cytomegalic viruses), after the protective cover is removed, the probe must be cleaned and subjected to disinfection with a bactericidal, fungicidal and virucidal effect. This is especially important in the event the cover ruptures during the vaginal examination, and the probe comes into direct contact with vaginal secretions or blood. The same likewise applies if the sterile protective cover is perforated during a follicular puncture. Usually special bactericidal, levurocidal and virucidal wipes or special submersion disinfection methods are available for disinfecting the vaginal ultrasound probes 11. Using special virucidal wipes on the probes is considered low-level disinfection. Primarily quaternary ammonia compounds are employed for this procedure. This method is easily applicable, has good cleaning characteristics, is effective against HPV and has high skin tolerance. However, it has the disadvantage of not removing all microorganisms during the disinfection process. Immersion procedures are high-level disinfection methods during which the transducer head is dipped in a special fluid for a certain amount of time. The disinfectants used for this include e. g. preparations based on glutaraldehyde or succinic aldehyde. However, in practice immersion disinfection has a number of disadvantages 13: 1. The procedure cannot be validated. 2. The probe permanently attached to the device must be placed in a separate holder and disinfected for at least 15 minutes. This is impracticable in routine operations in a clinic, outpatient facility or practice with a high number of examinations. 3. After this disinfection method, the probe has to be thoroughly rinsed with potable or higher-quality water in order to remove remnants of allergenic or locally toxic substances. 4. Frequently examinations take place in small interior areas with poor ventilation, thus under some circumstances posing an inhalant-related health hazard. 5. The required virucidal effect is frequently not achieved within 15 minutes 13. Furthermore, extended probe contact with liquid disinfecting agents in the long run results in increased wear of the transducer head membrane.Therefore it was interesting to note that in 2009 a fully-automatic disinfection system for ultrasound probes was introduced to the market (Trophon(EPR). This product, developed in Australia, promised relatively rapid high-level disinfection (HLD). During this software-controlled, mechanical disinfection procedure, the entire ultrasound probe (transducer head and handle) is placed in a sealed disinfection chamber, then hydrogen peroxide (H2O2) is discharged as an anti-microbial aerosol into the closed chamber.  The ultra-fine mist wets the entire surface of the probe with H2O2, thereby achieving high-level disinfection of the entire ultrasound probe. At the end of the process, a catalytic decomposition system breaks down the H2O2 into environmentally-friendly oxygen and water. When the chamber is opened, the probe is dry and ready for immediate use. The fully-automatic device was designed as a table unit to be placed directly next to the ultrasound equipment so that the probe does not need to be disconnected from the base unit. The entire disinfection process lasts 7 minutes: 2 minutes for the application and 5 minutes to remove the aerosol residue. In a validation study using carrier tests, Heeg and Gauer in 2014 showed that this procedure genuinely achieved HLD of ultrasound probes within 7 minutes, thus making it suitable for daily clinical routine. The procedure fulfills all requirements for HLD based on the medical device classification according to the legally-prescribed recommendation of the Commission for Hospital Hygiene and Prevention of Infection and the Federal Institute for Drugs and Medical Products (KRINKO/BfArM) in Germany. In the USA, this method was approved by the FDA as well as the leading probe manufacturers, and bears the testing certificate of the German Society for Hospital Hygiene (DGKH).All in all, it should be stated that the sole use of a latex protective cover when using a vaginal probe does not meet the necessary standard of care required for the provision of semi-critical medical products according to the joint recommendation of the German Federal Institute for Drugs and Medical Products (BfArM) and Commission for Hospital Hygiene and Prevention of Infection of the Robert Koch Institute, and constitutes a contravention of necessary patient and user protections. Use of the protective cover does not rule out smear infections and cross-contamination; therefore after each examination, the probe, after removal of the cover, must undergo disinfection measures providing bactericidal, fungicidal and virucidal effects. Since the transducer handle also poses a significant risk of transmission of germs, this component must likewise be sufficiently disinfected. In the event of perforation or rupture of the latex cover, thus resulting in the probe coming into contact with vaginal secretions or blood, the probe must be not only cleaned, but effectively disinfected with a virucide as well. It should also be noted that infection by bacteria and viruses can be caused not only by a contaminated probe, but by the ultrasound gel as well. According to studies by Heeg and Gauer 15, Buescher et al. as well as Ryndock et al., the fully automatic HLD system operated with hydrogen peroxide is currently the only validated system proven to provide HLD of ultrasound probes in a 7-minute cycle, thus suitable for application in the daily routine. Likewise it can also be presumed that this procedure also offers good material compatibility.

Subpubic Arch Angle and Mode of Delivery in Low-Risk Nulliparous Women.

OBJECTIVE: To assess whether subpubic arch angle (SPA) measurement before labor onset can predict labor outcome among low-risk pregnant women. METHODS: 3D ultrasound volume was transperineally acquired from a series of nulliparous women with uncomplicated pregnancy at term before the onset of labor. SPA was measured offline using Oblique View Extended Imaging (OVIX) on each volume performed by an investigator not involved in the clinical management. Labor outcome was prospectively investigated in the whole study group. RESULTS: Overall, 145 women were enrolled in the study. Of these, 83 underwent spontaneous vaginal delivery, whereas obstetric intervention was performed in 62 cases (Cesarean section in 40 and vacuum extraction in 22). The SPA appeared to be significantly narrower in the women submitted to obstetric intervention compared with those undergoing spontaneous vaginal delivery (116.8 ± 10.3° vs. 123.7 ± 9.6°, p < 0.01). At multivariate analysis SPA and maternal age were identified as independent predictors of the mode of delivery. On the other hand, the duration of labor did not show a significant relationship with SPA. CONCLUSIONS: In low-risk nulliparous women at term gestation, SPA measurement obtained by 3D ultrasound before the onset of labor seems to predict the likelihood of an obstetric intervention but not the duration of labor.