Applying a statistical method in transvaginal ultrasound training: lessons from the learning curve cumulative summation test (LC-CUSUM) for endometriosis mapping

Society of Radiologists in Ultrasound response to 'Proposed simplified protocol for initial assessment of endometriosis with transvaginal ultrasound'

Linked article: This Correspondence comments on Deslandes and Leonardi. Click here to view the article.

Ultrasound Diagnosis of Bowel Endometriosis

BACKGROUND

Bowel endometriosis is one of the more severe manifestations of deep endometriosis; it may cause pain and intestinal symptoms. The noninvasive diagnosis of bowel endometriosis is of crucial importance in planning the management of patients affected by this condition.

OBJECTIVES

This review aims to describe how transvaginal ultrasonography (TVS) is performed in patients with suspicion of rectosigmoid endometriosis, the diagnostic performance, and the strengths and limitations of this technique.

METHODS

To identify relevant literature, a literature search was performed across the PubMed and Google Scholar databases up to July 2024.

OUTCOME

Numerous meta-analyses have demonstrated that TVS has high diagnostic accuracy in diagnosing rectosigmoid endometriosis. Rectosigmoid nodules can present with different morphological characteristics, but they are typically described as irregular, hypoechoic nodules located in the anterior wall of the rectosigmoid colon. The presence of "soft markers," such as a negative sliding sign and kissing ovaries, can further reinforce the diagnosis of this condition. Posterolateral parametrial involvement often coexists with large rectal nodules. Introducing water contrast into the rectosigmoid does not improve the performance of TVS in diagnosing rectosigmoid endometriosis.

CONCLUSIONS AND OUTLOOK

TVS should be the first-line investigation in women suspected of having rectosigmoid endometriosis. The widespread use of TVS for the diagnosis of intestinal endometriosis can reduce diagnostic delays and facilitate the treatment of patients affected by this condition.

Learning Curve for Ultrasound Assessment of Myometrial Infiltration in Endometrial Cancer Visualizing Videoclips: Potential Implications for Training

BACKGROUND

Diagnostic accuracy for estimating myometrial infiltration by ultrasound in endometrial cancer requires experience. The objective of this study is to determine the learning curve (LC) for assessing myometrial infiltration in cases of endometrial cancer using transvaginal ultrasound (TVS).

METHODS

Five trainees (one staff radiologist and four fourth-year OB/GYN residents) participated in this study. All trainees had experience in performing TVS, but none of them had specific training on the assessment of myometrial infiltration. Trainees were given one specific lecture about the topic, and then they observed videoclips from 10 cases explained by the trainer. After this, all trainees visualized 45 videoclips of uterine ultrasound scans of endometrial cancer cases. The assessment of myometrial infiltration was based on the subjective impression. Definitive histology was used as a reference standard. Trainees stated whether myometrial infiltration was ≥50% or <50%. LC-CUSUM and standard CUSUM graphics were plotted to determine how many cases were needed to reach competence, allowing a mistake rate of 15%.

RESULTS

All trainees completed the study. LC-CUSUM graphics showed that three trainees reached competence at the 33rd, 35th and 36th case, respectively. All three of them kept the process under control after reaching competence. One trainee reached competence but did not maintain it in the cumulative analysis. One trainee did not reach competence.

CONCLUSION

Our study suggests that 30-40 cases would be needed to be trained for assessing myometrial infiltration by TVS by visual interpretation of videoclips by most trainees.

Clinical Diagnosis and Early Medical Management for Endometriosis: Consensus from Asian Expert Group

This work provides consensus guidance regarding clinical diagnosis and early medical management of endometriosis within Asia. Clinicians with expertise in endometriosis critically evaluated available evidence on clinical diagnosis and early medical management and their applicability to current clinical practices. Clinical diagnosis should focus on symptom recognition, which can be presumed to be endometriosis without laparoscopic confirmation. Transvaginal sonography can be appropriate for diagnosing pelvic endometriosis in select patients. For early empiric treatment, management of women with clinical presentation suggestive of endometriosis should be individualized and consider presentation and therapeutic need. Medical treatment is recommended to reduce endometriosis-associated pelvic pain for patients with no immediate pregnancy desires. Hormonal treatment can be considered for pelvic pain with a clinical endometriosis diagnosis; progestins are a first-line management option for early medical treatment, with oral progestin-based therapies generally a better option compared with combined oral contraceptives because of their safety profile. Dienogest can be used long-term if needed and a larger evidence base supports dienogest use compared with gonadotropin-releasing hormone agonists (GnRHa) as first-line medical therapy. GnRHa may be considered for first-line therapy in some specific situations or as short-term therapy before dienogest and non-steroidal anti-inflammatory drugs as add-on therapy for endometriosis-associated pelvic pain.

Evaluation of an e-learning program for the diagnosis of rectosigmoid endometriosis with rectal water contrast transvaginal ultrasonography (rectosonography)

This study aimed to evaluate the value of an e-learning program for the diagnosis of rectosigmoid endometriosis lesions using rectal water contrast transvaginal ultrasonography (rectosonography/RSG). Theoretical RSG training using videos with a commentary was offered online to healthcare professionals involved in ultrasound screening for endometriosis. A test (without correction) with 24 RSG video loops was used to assess the participants' baseline level before the training and their improvement afterwards. If the success rate post-training was below 80 %, the participant could start over with another series of 24 videos. Between February and June 2020, thirty participants took the training course (of which 80 % were obstetrics-gynaecology residents). The e-learning program resulted in a significant performance increase in the diagnosis of rectosigmoid endometriosis lesions, with a higher test success rate after the training compared to before (74.4 % and 63.6 % respectively; +10.8 %; 95 % CI [6,6; 15]; p < 0.001). Significant improvement was also observed regarding the overall skills involved in the ultrasound diagnosis of deep infiltrating endometriosis (+9.2 %; p < 0.001), the accurate diagnosis of the height of bowel lesions (+14.7 %; p < 0.001) and uterosacral ligament lesions (+8%; p < 0.005). In conclusion, our e-learning program led to a significant improvement of the diagnostic performance of digestive endometriosis using transvaginal ultrasound with intrarectal water contrast (rectosonography). Adding feedback to the post-test video loops could further increase the efficacy of the e-learning training.

Learning Curve for the Detection of Deep Infiltrating Endometriosis and Adenomyosis with 3-D Transvaginal Water Contrast Sonography

Three-dimensional rectosonography (RSG) is a transvaginal sonography technique using rectal water contrast and 3-D acquisitions. The main points of interest of 3-D RSG could be its easy accessibility and its quick learning curve, especially with respect to rectosigmoid lesions. The objective of this prospective observational study was to assess the learning curve of 3-D RSG for the diagnosis of rectosigmoid lesions and for various other locations of deep endometriosis (DE), endometriomas and adenomyosis. From April 2017 to November 2017, 116 patients with suspected pelvic endometriosis were referred to the Croix-Rousse University Hospital, and those who underwent 3-D RSG were included in our study. After a short training period, four residents were asked to perform 3-D RSG by themselves. Each procedure was systematically controlled immediately afterward by a single expert sonographer. The success of the procedure involved the correct identification of various locations of endometriosis (rectosigmoid, uterosacral ligament, retrocervical space, vagina, bladder and ovaries) and adenomyosis, using the expert sonographer's examination as the reference technique. The learning curve was generated using these data and assessed using the Learning Curve Cumulative Summation Test (LC-CUSUM) method. The pooled LC-CUSUM revealed that the required level of achievement was reached after 24 3-D RSGs were performed for the diagnosis of rectosigmoid lesions. All four residents were significantly competent in diagnosing rectosigmoid lesions at the end of their training period, with an α risk <0.05 (T1, p = 0.03; T2, p = 0.0002; T3, p = 0.05; T4, p = 0.02). The LC-CUSUM analysis confirmed that competency was achieved for vaginal DE, torus uterinum DE, US DE, bladder DE, endometriomas and adenomyosis within 17, 27, 38, 19, 17 and 33 scans, respectively. This study provides evidence that the skills required to diagnose endometriosis lesions and adenomyosis with 3-D RSG can be acquired after a brief learning period in an expert center.

The Reproducibility of Ultrasonographic Findings of Rectosigmoid Endometriosis Among Examiners With Different Level of Expertise

OBJECTIVE

To analyze the reproducibility of ultrasonographic (US) findings of rectosigmoid endometriosis among examiners with different level of expertise using stored three-dimensional (3D) volumes of the posterior compartment of the pelvis as a part of SANABA (Sardinia-Navarra-Barcelona) collaborative study.

MATERIALS AND METHODS

Six examiners in 3 academic Department of Obstetrics and Gynecology, with different levels of experience and blinded to each other, evaluated 60 stored 3D volumes from the posterior compartment of the pelvis and looked for the presence or absence of features of rectosigmoid endometriotic lesions defined as an irregular hypoechoic nodule with or without hypoechoic foci at the level of the muscularis propria of the anterior wall rectum sigma. Multiplanar view and virtual navigation were used. All examiners had to assess the 3D volume of posterior compartment of the pelvis and classify it as present or absent disease. To analyze intra-observer and the inter-observer agreements, each examiner performed the assessment twice with a 2-week interval between the first and second assessments. Reproducibility was assessed by calculating the weighted Kappa index.

RESULTS

Intra-observer reproducibility was moderate to very good for all observers (Kappa index ranging from 0.49 to 0.96) associated with a good diagnostic accuracy of each reader. Inter-observer reproducibility was fair to very good (Kappa index range: 0.21-0.87).

CONCLUSIONS

The typical US sign of rectosigmoid endometriosis is reasonably recognizable to observers with different level of expertise when assessed in stored 3D volumes.

Assessment of operator performance during oocyte retrievals: residents' learning curve and continuous monitoring of senior physicians

BACKGROUND

The learning curve cumulative summation test (LC CUSUM test) allows to define an individualized learning curve and determine the moment when clinical proficiency is attained. After acquisition of the skills, the cumulative summation test (CUSUM test) allows to monitor the maintenance of the required level over time. The LC CUSUM test has been frequently used in the field of Obstetrics and Gynecology (Ob/Gyn) for several procedures, but only once for OR.

METHODS

We performed a retrospective study at Angers university hospital between May 2017 and September 2018. Seven Ob/Gyn residents and 5 senior physicians were included, and all OR performed during that time (n = 690) were analyzed. The performance index assessed was the oocyte retrieval rate (ORR), defined as the ratio of oocytes retrieved to follicles aspirated. We used the LC CUSUM test to analyze the learning curves of residents, and the CUSUM test to monitor the performance of senior physicians. An ORR ≥50% in 60% of retrievals was defined as the threshold for clinical proficiency.

RESULTS

Six hundred seventy-four oocyte retrieval (OR) were included: 315 were performed by residents, 220 by senior physicians, and 139 by both residents and physicians (mixed retrievals). Four residents (57%) reached the threshold after aspirating 82, 67, 53 and 46 ovaries, respectively. The mean number of ovaries aspirated in order to reach clinical proficiency was 62, and the mean number of weeks needed was 21. The duration of the learning period varied between 26 and 80 days. Two senior physicians (40%) remained proficient across the duration of the study, while two physicians (40%) had one statistically "suboptimal" OR, and one physician (20%) had two suboptimal retrievals.

CONCLUSION

There is a large variability in the duration of the learning period and the number of procedures needed for a resident to master OR. Senior physicians maintain an adequate performance.

Ultrasound of the Uterosacral Ligament, Parametrium, and Paracervix: Disagreement in Terminology between Imaging Anatomy and Modern Gynecologic Surgery

Ultrasound is an effective tool to detect and characterize lesions of the uterosacral ligament, parametrium, and paracervix. They may be the site of diseases such as endometriosis and the later stages of cervical cancer. Endometriosis and advanced stages of cervical cancer may infiltrate the parametrium and may also involve the ureter, resulting in a more complex surgery. New functional, surgical anatomy requires the complete diagnostic description of retroperitoneal spaces and tissues that contain vessels and nerves. Most endometriosis lesions and cervical cancer spread involve the cervical section of the uterosacral ligament, which is close to tissues, namely the parametrium and paracervix, which contain vessels and important nerves and nerve anastomoses of the inferior hypogastric plexus. Efferent fibers of the plexus travel to the rectum, uterus, rectovaginal ligament, deep vesicouterine ligament, and bladder. These efferent fibers are essential for bladder and rectal functionality so tailored nerve-sparing surgery became a standard approach for treating deep infiltrating endometriosis and cervical cancer. An accurate diagnosis by ultrasound has significant clinical impact and is important for appropriate treatment. In this article, we try to establish a common terminology between imaging diagnostic and modern surgical anatomy.

One-Size-Fits-All Approach Does Not Work for Gynecology Trainees Learning Endometriosis Ultrasound Skills

OBJECTIVES

To evaluate whether gynecologic surgical trainees (fellows) can become competent in the real-time classification of the pouch of Douglas (POD) obliteration state and direct visualization of bowel deep endometriosis (DE) during a program with a prespecified number of transvaginal ultrasound (TVUS) examinations.

METHODS

We performed a prospective study between December 2017 and December 2018. Three fellows (F1-F3) performed 50 scans each, which were all supervised by an expert sonologist, who performed the reference standard TVUS examination. The fellows performed a focused TVUS examination to assess the bowel and POD state, having been blinded to the patient's clinical history and reference standard findings. Immediate feedback and hands-on teaching were provided after each of the fellow's official classifications. To evaluate the number of scans needed to gain competency, the cumulative summation test for the learning curve was used.

RESULTS

A total of 150 examinations were performed on 145 patients. Twenty-six (17.9%) patients had a diagnosis of bowel DE, and 34 (23.4%) were classified as having a negative sliding sign by the reference standard. The overall accuracy of the presence/absence of bowel DE was 90% (range, 82%-94%). The overall accuracy of POD state classification was 93% (range, 90%-96%). The cumulative summation test for the learning curve for bowel DE showed that F1 did not reach competency by 50 scans, whereas F2 and F3 required 21 and 25 scans, respectively. For POD obliteration, F2 did not reach competency, whereas F1 and F3 required 40 and 22 scans.

CONCLUSIONS

Not all trainees can reach competency for TVUS evaluations of POD obliteration and bowel DE in a predefined number of scans.

Differential Diagnosis of Endometriosis by Ultrasound: A Rising Challenge

Ultrasound is an effective tool to detect and characterize endometriosis lesions. Variances in endometriosis lesions' appearance and distorted anatomy secondary to adhesions and fibrosis present as major difficulties during the complete sonographic evaluation of pelvic endometriosis. Currently, differential diagnosis of endometriosis to distinguish it from other diseases represents the hardest challenge and affects subsequent treatment. Several gynecological and non-gynecological conditions can mimic deep-infiltrating endometriosis. For example, abdominopelvic endometriosis may present as atypical lesions by ultrasound. Here, we present an overview of benign and malignant diseases that may resemble endometriosis of the internal genitalia, bowels, bladder, ureter, peritoneum, retroperitoneum, as well as less common locations. An accurate diagnosis of endometriosis has significant clinical impact and is important for appropriate treatment.

Resuscitation Opportunities for Fellows of Very Low Birth Weight Infants in the Vermont Oxford Network

BACKGROUND

Neonatal-perinatal medicine (NPM) fellowship programs must provide adequate delivery room (DR) experience to ensure that physicians can independently provide neonatal resuscitation to very low birth weight (VLBW) infants. The availability of learning opportunities is unknown.

METHODS

The number of VLBW (≤1500 g) and extremely low birth weight (ELBW) (<1000 g) deliveries, uses of continuous positive airway pressure, intubation, chest compressions, and epinephrine over 3 years at accredited civilian NPM fellowship program delivery hospitals were determined from the Vermont Oxford Network from 2012 to 2017. Using Poisson distributions, we estimated the expected probabilities of fellows experiencing a given number of cases over 3 years at each program.

RESULTS

Of the 94 NPM fellowships, 86 programs with 115 delivery hospitals and 62 699 VLBW deliveries (28 703 ELBW) were included. During a 3-year fellowship, the mean number of deliveries per fellow ranged from 14 to 214 (median: 60) for VLBWs and 7 to 107 (median: 27) for ELBWs. One-half of fellows were expected to see ≤23 ELBW deliveries and 52 VLBW deliveries, 24 instances of continuous positive airway pressure, 23 intubations, 2 instances of chest compressions, and 1 treatment with epinephrine.

CONCLUSIONS

The number of opportunities available to fellows for managing VLBW and ELBW infants in the DR is highly variable among programs. Fellows' exposure to key, high-risk DR procedures such as cardiopulmonary resuscitation is low at all programs. Fellowship programs should track fellow exposure to neonatal resuscitations in the DR and integrate supplemental learning opportunities. Given the low numbers, the number of new and existing NPM programs should be considered.

Learning curve for detection of pelvic parts of ureters by transvaginal sonography: feasibility study

OBJECTIVE

To investigate how many examinations it takes to be able to identify the pelvic parts of the ureters on transvaginal sonography (TVS).

METHODS

This was a prospective study including consecutive women attending a gynecological outpatient clinic in a tertiary referral setting. Prior to commencement of the study, three trainees, with a focus on gynecological surgery and TVS but with no experience in identifying ureters, each observed an expert examiner performing 10 routine TVS examinations, including identification of both ureters. All were standardized gynecological TVS examinations, with visualization of the pelvic part of both ureters. Consecutive women were then examined, first by the expert, unobserved by the trainees, and then by one of the three trainees, in the presence of the expert. To ensure that identification of the pelvic parts of the ureters could be incorporated feasibly into routine gynecological TVS in a tertiary referral setting, a time limit of 150 s was set for successful identification of each ureter. A successful examination was defined by identifying both ureters within the time limit. The number of women examined by each trainee was determined by how quickly they achieved proficiency, which was evaluated using the learning curve cumulative summation (LC-CUSUM) score.

RESULTS

Between January 2017 and June 2017, a total of 140 women were recruited for the study, with 135 patients being included in the final analysis. The three trainees were able to identify the right ureter after a maximum of 48 (range, 34-48) TVS examinations, and the left ureter after a maximum of 47 (range, 27-47) TVS examinations.

CONCLUSIONS

Sonographers and/or gynecologists who are familiar with gynecological TVS should be able to become proficient in identifying both ureters after 40-50 TVS examinations. Detection of the ureters is a feasible part of the TVS workup of patients attending a clinic in a tertiary referral center. © 2019 the Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Learning curve for ultrasonographic diagnosis of deep infiltrating endometriosis using structured offline training program

OBJECTIVE

To assess the learning curves of trainees during a structured offline/hands-on training program for the ultrasonographic diagnosis of deep infiltrating endometriosis (DIE).

METHODS

Four trainees (all Ob/Gyn postgraduates with at least 5 years' experience in ultrasonography in obstetrics and gynecology, but with no experience of sonographic examination of DIE) participated in the study. They underwent a 2-week training program with a single trainer. Day 1  was devoted to theoretical issues and guided offline analysis of 10 three-dimensional ultrasound volumes. During the following days, four sessions of real-time sonographic examinations were performed in a DIE referral center ultrasound unit. In between these sessions, the trainees analyzed four datasets offline, each containing 25 volumes. At the end of each set, misinterpreted volumes were reassessed with the trainer. Presence or absence of DIE at surgery was considered the gold standard. The trainees' learning process was evaluated by learning-curve cumulative summation (LC-CUSUM) and the deviations of the trainees' level of performance at the control stage was assessed by CUSUM (standard CUSUM), for different locations of DIE.

RESULTS

The trainees reached competence after an average of 17 (range, 14-21) evaluations for bladder, 40 (range, 30-60) for rectosigmoid, 25 (range, 14-34) for forniceal, 44 (range, 25-66) for uterosacral ligament (USL) and 21 (range, 14-43) for rectovaginal septum (RVS) locations of DIE, and then kept the process under control, with error levels of less than 4.5% until the end of the test. The overall accuracy for each trainee in diagnosis of DIE at the different locations ranged from 0.91 to 0.98 for bladder DIE, from 0.80 to 0.94 for rectosigmoid DIE, from 0.90 to 0.94 for forniceal DIE, from 0.79 to 0.82 for USL DIE and from 0.89 to 0.98 for RVS DIE.

CONCLUSIONS

The suggested 2-week training program, based on a mixture of offline and live scanning sessions, is feasible and apparently provides effective training for the ultrasonographic diagnosis of DIE. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.