Automatic measurement of head-perineum distance during intrapartum ultrasound: description of the technique and preliminary results

To evaluate the performance of a new ultrasound technique for the automatic assessment of the change in head-perineum distance (delta-HPD) and angle of progression (delta-AoP) during the active phase of the second stage of labor. This was a prospective observational cohort study including singleton term pregnancies with fetuses in cephalic presentation during the active phase of the second stage of labor. In each patient, two videoclips of 10 s each were acquired transperineally, one in the axial and one in the sagittal plane, between rest and the acme of an expulsive effort, in order to measure HPD and AoP, respectively. The videoclips were processed offline and the difference between the acme of the pushing effort and rest in HPD (delta-HPD) and AoP (delta-AoP) was calculated, first manually by an experienced sonographer and then using a new automatic technique. The reliability of the automatic algorithm was evaluated by comparing the automatic measurements with those obtained manually, which was considered as the reference gold standard. Overall, 27 women were included. A significant correlation was observed between the measurements obtained by the automatic and the manual methods for both delta-HPD (intraclass correlation coefficient (ICC) = 0.97) and delta-AoP (ICC = 0.99). The high accuracy provided by the automatic algorithm was confirmed by the high values of the coefficient of determination (r2 = 0.98 for both delta-HPD and delta-AoP) and the low residual errors (root mean square error = 1.2 mm for delta-HPD and 1.5° for delta-AoP). A Bland-Altman analysis showed a mean difference of 0.52 mm (limits of agreement, -1.58 to 2.62 mm) for delta-HPD (P = 0.034) and 0.35° (limits of agreement, -2.54 to 3.09°) for delta-AoP (P = 0.39) between the manual and automatic measurements. The automatic assessment of delta-AoP and delta-HPD during maternal pushing efforts is feasible. The automatic measurement of delta-AoP appears to be reliable when compared with the gold standard manual measurement by an experienced operator. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Objectives This was an observational study on cervical length and head perineum distance and the prediction of time of delivery. One-hundred and twenty-five nulliparous women with uncomplicated, term, singleton pregnancy were recruited when they presented to the labor ward with show or infrequent painful uterine contractions (less than three contractions in ten minutes on a 30 min cardiotocogram). Apart from digital vaginal examination to assess cervical length and dilatation, sonographic cervical length and head perineum distance were measured by two-dimensional ultrasound. We compared women who delivered within 72 h of presentation of labor symptoms, with women who did not. After excluding ten women whose labor was induced and delivered within 72 h of presentation, one hundred and fifteen women were included for final data analysis. Main findings Forty-nine women (42.6%) delivered while sixty-six women (57.4%) remained undelivered at 72 h of presentation of symptoms of labor. There was no statistically significant difference between the two groups on age, presence of show, contractions, fetal head station and presentation and mode of delivery. For the group who had delivered within 72 h of presentation of labor symptoms, the mean sonographic cervical length was 1.87 cm ± 0.62 cm, while the head perineum distance was 6.01 cm ± 1.15 cm. For the other group, the mean sonographic cervical length was 2.10 cm ± 0.83 cm; head perineum distance was 6.03 cm ± 1.18 cm. There was no statistically significant difference between the groups for both sonographic cervical length (p = .90); and head perineum distance (p = .08). We also compared the cervical length measured by digital vaginal examination versus sonography. The median sonographic measurements were 1.47 cm, 2.11 cm and 2.79 cm at “1 cm,” “2 cm” and “3 cm” digital vaginal measurement, respectively. However, there was extensive overlap between digitally and sonographically measured cervical length. Prediction accuracy of cervical length and head perineum distance was poor. The area under curve (AUC) of receiver operating characteristic (ROC) curve were 0.433 for sonographic cervical length and 0.501 for HPD. Conclusion Transperineal sonographical assessment of cervical length and head perineum distance before labor was not useful in predicting the time of delivery. However, it can be explored as an alternative assessment method when digital vaginal examination is not preferred.

To evaluate the impact of body mass index (BMI) on sonographic measurement of head perineum distance (HPD) before operative vaginal delivery (OVD). This was a single-center retrospective cohort study (Lille, France) conducted from March 1, 2019 to October 31, 2020 including all singleton and OVD. HPD measurement was systematically performed without and with compression on the perineum soft tissues. The level of station was defined by vaginal examination and three maternal BMI groups were defined (normal BMI [<24.9 kg/m2] vs overweight [25-29.9 kg/m2] vs obese [≥30 kg/m2]). HPD measures were compared between BMI groups and compression, in distinct level of station, using a two-factor analysis of variance including BMI groups, the compression, and the interaction term BMI group compression. A total of 775 women were included: 488 with normal BMI, 181 overweight patients and 106 obese patients. The measurement of HPD before OVD without and with compression on the soft tissues was significantly different between the BMI groups only in the lower part, particularly between normal BMI and obese patients (mean difference (95% CI): 6.6 mm (4.0 to 9.2) without compression; 3.8 (1.1 to 6.4) with compression). The values of HPD without and with compression on the soft tissues on the maternal perineum were different according to the maternal BMI concerning lower part station. Thus, it seems important to define thresholds of HPD measures corresponding to each head station levels according to maternal BMI.

Predictive value of head-perineum distance measured at the initiation of the active second stage of labor on the mode of delivery: A prospective cohort study

Determine if head-perineum distance (HPD) measurement before vacuum extraction (VE) was predictive of an obstetric anal sphincter injury (OASIS) occurrence. Retrospective, bicentric (Lille and Poissy, France) cohort study conducted from January 2019 to June 2020. All VE in singleton pregnancies of ≥34weeks were included. HPD measurement was performed without compression of the tissues before each VE. The judgment criterion was the occurrence of an OASIS. Of 12 568 deliveries, VE was performed in 1093 (8.6%). Among these 1093 women undergoing VE, 675 (61.7%) with HPD measurement were included. OASIS was found in 6.5% of women (n=44; 95% CI 4.5-8.7). HPD was not associated with OASIS (38.5±12.6mm in women with OASIS vs 37.4±12.0mm in women without; adjusted OR [aOR] per 5mm increase=0.92; 95% CI 0.79-1.06). Increased HPD was associated with higher risk of sequential extraction (aOR=1.19; 95% CI 1.06-1.32), extraction duration >10min (aOR=1.12; 95% CI 1.02-1.23) and shoulder dystocia (aOR=1.20; 95% CI 1.03-1.40). Ultrasound-measured head-perineum distance does not predict the occurrence of obstetric anal sphincter injury during a VE. The interest of HPD is more about predicting the success or difficulty of VE rather its specific complications.

OBJECTIVE: We aimed to assess the accuracy of intrapartum transperineal ultrasonography that is non-invasive, easy to learn, rapid to perform, comfortable for pregnant women, and low-cost method to evaluate the progress of labor objectively.STUDY DESIGN: We evaluated two hundred-ten singleton pregnant women at term with cephalic presentation who went into active labor via intrapartum transperineal ultrasonography using the angle of progression and head-perineum distance. Maternal characteristics, conventional vaginal examination findings, mode of delivery, and neonatal results were noted. The data were compared using correlation and regression analysis.RESULTS: The relationships between the descent of clinical fetal head station, the increase of angle of progression (p=0.001), and the decrease of head-perineum distance (p=0.001) were statistically significant. The receiver operating characteristics curve showed that measurement of angle of progression with &lt;110.5 degrees (p=0.001) and measurement of head-perineum distance with &gt;52.5 millimeters (p=0.001) were associated with emergent cesarean delivery. For the prediction of delivery mode, both angle of progression and head-perineum distance had high sensitivity and specificity.CONCLUSIONS: Intrapartum transperineal ultrasonography parameters were in agreement with each other and conventional vaginal examination for determination of delivery mode. Head-perineum distance was a parity-dependent measurement whilst angle of progression was parity-independent.

Occiput posterior position is associated with labor arrest, need for operative delivery, and failed instrumental vaginal delivery, with resulting adverse peripartum outcomes. Vacuum extraction is the most commonly performed type of instrumental delivery worldwide. This study aimed to investigate the outcome of vacuum extraction in fetuses with sonographically confirmed occiput posterior position before the procedure. Singleton pregnancies at term with sonographically confirmed fetal occiput posterior position before the vacuum extraction were enrolled in 3 academic maternity units. Fetal head station was assessed using transperineal sonography measuring the angle of progression and the head-perineum distance. The primary outcome was failed vacuum extraction, defined as the need for cesarean delivery. Secondary outcomes included adverse maternal and/or adverse neonatal outcomes and complicated vacuum extraction, with the latter defined as failed vacuum extraction or at least 3 out of the following 6 parameters: 5-minute Apgar score <7, neonatal acidemia, admission to the neonatal intensive care unit, neonatal trauma, postpartum hemorrhage, and obstetrical anal sphincter injuries. Among the 98 patients included in the study, vacuum extraction was successful in 94 (96%). Logistic regression analysis showed that the measurement of the head-perineum distance was the only factor independently associated with failed vacuum extraction (odds ratio, 1.25; 95% confidence interval, 1.02-1.55; P=.03), with an area under the curve of 0.79 (P=.04). A head-perineum distance cutoff value of 38.5 mm discriminated between successful and failed vacuum extraction, yielding a sensitivity of 75.0% (3/4), specificity of 84.0% (79/94), positive likelihood ratio of 4.7, and negative likelihood ratio of 0.3. Vacuum extraction is successful in 95% of fetuses with occiput posterior position confirmed at ultrasound. The head-perineum distance measured at transperineal ultrasound has a significant albeit weak association with the outcome of vacuum extraction.

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. 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. 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). We found excellent intra-observer repeatability, good correlation but significant difference between devices. Women reported less discomfort with ultrasound than with clinical examinations.

To evaluate the accuracy and reliability of an automatic ultrasound technique for assessment of the angle of progression (AoP) during labor. Thirty-nine pregnant women in the second stage of labor, with fetus in cephalic presentation, underwent conventional labor management with additional translabial sonographic examination. AoP was measured in a total of 95 acquisition sessions, both automatically by an innovative algorithm and manually by an experienced sonographer, who was blinded to the algorithm outcome. The results obtained from the manual measurement were used as the reference against which the performance of the algorithm was assessed. In order to overcome the common difficulties encountered when visualizing by sonography the pubic symphysis, the AoP was measured by considering as the symphysis landmark its centroid rather than its distal point, thereby assuring high measurement reliability and reproducibility, while maintaining objectivity and accuracy in the evaluation of progression of labor. There was a strong and statistically significant correlation between AoP values measured by the algorithm and the reference values (r = 0.99, P < 0.001). The high accuracy provided by the automatic method was also highlighted by the corresponding high values of the coefficient of determination (r2 = 0.98) and the low residual errors (root mean square error = 2°27' (2.1%)). The global agreement between the two methods, assessed through Bland-Altman analysis, resulted in a negligible mean difference of 1°1' (limits of agreement, 4°29'). The proposed automatic algorithm is a reliable technique for measurement of the AoP. Its (relative) operator-independence has the potential to reduce human errors and speed up ultrasound acquisition time, which should facilitate management of women during labor. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Correlation between manual and automatic measurements of the atrial signal in VDD leadless pacemakers (Micra AV)

ObjectiveThe main study objective was to develop a novel shoulder dystocia (SD) prediction score using ultrasound‐based head–perineum distance measured before an operative vaginal delivery (OVD).MethodsThis retrospective unicentric study (Lille, France) included all cases of OVD of singleton pregnancies from March 2019 to October 2020, with cephalic presentation and > 37 weeks of gestation, for which intrapartum sonography was performed. A multiclass‐penalized logistic regression model was used to develop the SD prognostic score, with missing values imputed by multiple imputations.ResultsAmong the 1708 patients with OVD, 773 who underwent ultrasound for head–perineum distance were included. SD occurred in 99 cases (12.8%). The SD's predicting factors (and their weights) included the following: maternal age younger than 28 years (3 points); multiparous (4 points); induced labor (4 points); gestational diabetes (3 points); and head–perineum distance without pressure (≤20 mm [−2 points], using 21–30 mm as reference, 31–40 mm [2 points], 41–50 mm [4 points], 51–60 mm [6 points], and >60 mm [8 points]). Three patient risk subgroups were categorized as score range (occurrence percentage) as low risk: < 3 (< 10%), high risk: 3–8 (10%–20%), and very high risk: > 8 (> 20%).ConclusionThe developed scoring system may help predict SD occurrence during OVD using five delivery room parameters. Replication with other populations and prospective cohorts will be needed for validation.

- Use of ultrasound before operative vaginal delivery (OVD), especially head-perineum distance (HPD) measurement, has shown promising results in the prediction of vacuum-assisted delivery failure. However, the studies were monocentric and there was variation in reported thresholds. To assess HPD measurement as a predictor of the failure of vacuum-assisted delivery, requiring an instrument change. Multicenter, retrospective cohort study in three tertiary maternity hospitals in France, from January 2019 to December 2020. Analyses included all vacuum-assisted delivery attempts in singleton pregnancies of ≥ 34 weeks gestation and for which an ultrasound HPD measurement was available. Vacuum deliveries were classified as success or failure (i.e., leading to an instrument change). - Among 23,974 deliveries, vacuum delivery was performed in 2,432 cases (10.1 %) among which 1,197 (49.2 %) had HPD measurements. Instrument change occurred in 123 (10.3 %). The area under the curve for predicting the failure of a vaginal delivery with vacuum according to HPD measurement was 0.58, smaller in the success group (40.1 ± 12.6 mm vs 43.3 ± 10.9 mm, p <0.001). After multivariable analysis, gestational age and HPD were significantly associated with OVD failure (respectively, OR(95 %CI) 1.26 (1.05-1.51), p=0.015, 1.14 (1.04-1.25), p=0.004); whereas fetal head position did not reach the significance level (p=0.06). However more failure were observed in case of transverse position compared to anterior position (ORa = 2.10 (1.13 to 3.90)). - In our multicenter and retrospective study, HPD measurement has a low predictive value for the need for instrument change in vacuum-assisted OVD. It will be interesting to test mix models including maternal and sonographic parameters.

Using machine learning to automatically measure axial vertebral rotation on radiographs in adolescents with idiopathic scoliosis.

To evaluate the tool of automatic measuring CBCT, developed based on deep learning technology, and to compare its accuracy with manual measurement and to verify its effectiveness and feasibility. Twenty-nine adult patients (11 males, 18 females) with mean age of (31.31±13.77) years old were enrolled, CBCT of enrolled patients were collected, and 427 transverse sections of alveolar teeth were extracted(5-5 position). A novel Segment Anything Model(SAM) -based interactive segmentation and measurement tool was developed and applied to the assessment of alveolar socket dimensions in CBCT. Manual and automatic measurements of bone mass in the buccal and lingual transverse section of the alveolar socket were performed by establishing the test set and the validation set, respectively, and the data were compared. There was significant correlation and consistency between CBCT automatic measurement method and manual measurement. The coefficient of determination(R2) of regression analysis in test set was 0.942, the measurement error in validation set was mainly varing between -0.43～0.47 mm, Pearson correlation coefficient was 0.9746 (P＜0.001). This study developed an automatic CBCT measurement tool based on SAM through deep learning, with high accuracy and significantly improved the efficiency of alveolar socket measurement.

Agreement and Reproducibility of Automatic Versus Manual Measurement of QT Interval and QT Dispersion