How to assess the ureters during pelvic ultrasound

Ultrasound assessment of the pelvic sidewall: methodological consensus opinion

A standardized methodology for the ultrasound evaluation of the pelvic sidewall has not been proposed to date. Herein, a collaborative group of gynecologists and gynecological oncologists with extensive ultrasound experience presents a systematic methodology for the ultrasonographic evaluation of structures within the pelvic sidewall. Five categories of anatomical structures are described (muscles, vessels, lymph nodes, nerves and ureters). A step-by-step transvaginal ultrasound (or, when this is not feasible, transrectal ultrasound) approach is outlined for the evaluation of each anatomical landmark within these categories. Accurate assessment of the pelvic sidewall using a standardized approach improves the detection and diagnosis of non-gynecological pathologies that may mimic gynecological tumors, reducing the risk of unnecessary and even harmful intervention. Furthermore, it plays an important role in completing the staging of malignant gynecological conditions. Transvaginal or transrectal ultrasound therefore represents a viable alternative to magnetic resonance imaging in the preoperative evaluation of lesions affecting the pelvic sidewall, if performed by an expert sonographer. A series of videoclips showing normal and abnormal findings within each respective category illustrates how establishing a universally applicable approach for evaluating this crucial region will be helpful for assessing both benign and malignant conditions affecting the pelvic sidewall. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Development of deep pelvic endometriosis following acute haemoperitoneum: a prospective ultrasound study

STUDY QUESTION

Is acute haemoperitoneum that is managed conservatively a precursor of deep endometriosis?

SUMMARY ANSWER

Our study provides evidence to suggest that acute haemoperitoneum may lead to the development of deep endometriosis in a significant proportion of cases.

WHAT IS KNOWN ALREADY

A recent pilot study was the first to suggest that acute haemoperitoneum could be a precursor of deep endometriosis. However, the sample size was small, and the follow-up was not standardized owing to unknown rates of clot absorption and development of endometriosis.

STUDY DESIGN SIZE DURATION

This was a prospective observational cohort study conducted at a single centre over a 31-month period. A required sample size of 30 was calculated using results from a previous study, with a minimum of 15 women each in the groups with and without significant haemoperitoneum (study and control groups, respectively). A total of 59 women were recruited to the study and eight were lost to follow-up. The final sample comprised 51 women, 15 in the study group and 36 in the control group.

PARTICIPANTS/MATERIALS SETTING METHODS

All non-pregnant, premenopausal women aged 18-50 years who consecutively presented to our dedicated gynaecological diagnostic unit with severe acute lower abdominal pain were eligible for this study. We only included women who were clinically stable and were suitable for conservative management. Those with prior history or evidence of endometriosis on their initial ultrasound scan, previous hysterectomy, or bilateral oophorectomy were excluded. Participants had standardized follow-up visits for 6 months, with pelvic ultrasound scans and the British Society of Gynaecological Endoscopy pelvic pain questionnaires completed at each visit. The primary outcome was the sonographically confirmed presence of newly formed endometriosis. Secondary outcomes were the presence and change of pelvic pain symptoms and health-related quality of life (HR-QOL).

MAIN RESULTS AND THE ROLE OF CHANCE

After completion of follow-up, 7/15 (47%; 95% CI 21.3-71.4%) women presenting with acute haemoperitoneum (study group) developed sonographic evidence of deep endometriosis, compared to 0/36 (0%; 97.5% CI 0.0-9.7%) women in the control group. A ruptured functional haemorrhagic cyst was the most common cause of haemoperitoneum, occurring in 13/15 cases (87%). The time from the initial event to sonographic evidence of endometriosis varied from 2 to 6 months. The EuroQol visual analogue scores were not significantly different at baseline between the groups that developed and did not develop endometriosis [28 (interquartile range (IQR) 15-40, n = 6) vs 56 (IQR 35-75, n = 44), P = 0.09], while the EuroQol-5D values were lower in the endometriosis group [-0.01 (IQR -0.07 to 0.19, n = 6) vs 0.62 (IQR 0.24-0.73, n = 44), P = 0.002]. At 6 months, the EuroQol-5D scores were improved in both groups, but remained significantly lower in the endometriosis group compared to the no endometriosis group [0.69 (IQR 0.66-0.80, n = 6) vs 0.85 (IQR 0.76-1.00, n = 44), P = 0.03]. There was no clinically relevant difference in the pelvic pain scores at either time point.

LIMITATIONS REASONS FOR CAUTION

It remains uncertain whether minimal, superficial endometriosis existed at commencement of the study and had a role in the development of deep endometriosis. Although the ultrasound findings were in keeping with deep endometriosis, this was not confirmed histologically. The pelvic pain and HR-QOL findings could have been influenced by the baseline scores being taken when the patient was admitted with acute pain. Also, the sample size was too small to draw reliable conclusions regarding the impact of newly developed endometriosis on QoL.

WIDER IMPLICATIONS OF THE FINDINGS

Our study provides further evidence showing that significant haemoperitoneum may be a precursor of deep endometriosis. Haemodynamically stable women presenting with acute pelvic pain and significant haemoperitoneum should be counselled about the risk of developing deep endometriosis. Interventional studies should be carried out in the future to see whether laparoscopy and pelvic washout could prevent development of deep endometriosis. Preventative strategies, including treatment to suppress ovulation and formation of functional cysts, should be further investigated. This includes the combined and progesterone-only contraceptive pills. Larger future studies are also required to assess women over a longer period of time, with adjustment for confounding factors, to evaluate a possible effect on HR-QOL and pain symptoms.

STUDY FUNDING/COMPETING INTERESTS

Funding was obtained from The Gynaecology Ultrasound Centre, London, UK. TT received personal fees from GE, Samsung, Medtronic, and Merck for lectures on ultrasound. TT also received a postdoctoral grant from the South-Eastern Norwegian Health Authority (grant number 2020083).

TRIAL REGISTRATION NUMBER

researchregistry6472.

Recanalize ureteral stents with focused ultrasound

BACKGROUND

Maintaining ureteral patency is imperative to preventing renal injury and systemic infection. Ureteral stents are small conduits connecting the kidney and the bladder. They have been widely used to treat ureteral obstructions and ureteral leaks. The most problematic and frequent stent-associated complication is stent encrustation. This occurs when mineral crystals (e.g. calcium, oxalate, phosphorus, struvite) are deposited onto the surface and internal lumen of the stent. Encrustation can lead to the obstruction of a stent and increases risk of systemic infection. As a result, ureteral stents need to be replaced typically every 2-3 months.

PURPOSE

In this study, we present a non-invasive, high-intensity focused ultrasound (HIFU)-based technique to recanalize obstructed stents. By taking advantage of the mechanical force produced by a HIFU beam, including acoustic radiation force, acoustic streaming, and cavitation, HIFU can break up encrustations, clearing the stent of obstruction.

METHODS

The ureteral stents for this study were obtained from patients undergoing ureteral stent removal. Under the guidance of ultrasound imaging, the encrustation in the stents were located, and then targeted by HIFU at frequencies of 0.25 and 1 MHz. The duty cycle of HIFU was 10%, and the HIFU burst repetition rate was 1 Hz, while the HIFU amplitude was varied to find the threshold pressure that would displace encrustations. The treatment duration was limited at 2 min (or 120 shots from HIFU). The treatments were carried out in two different orientations (parallel and perpendicular) of the ureteral stent with respect to the HIFU beam. For each setting, five treatments were conducted for a maximum duration of 2 min. During the entire treatment, an ultrasound imaging system was used to monitor the movement of encrustations inside the stent. The peak negative HIFU pressures needed to move the encrustations inside the stent was recorded for quantitative analysis.

RESULTS

Our results demonstrated that at both 0.25 and 1 MHz ultrasound frequencies, obstructed stents could be recanalized. At 0.25 MHz, the needed average peak negative pressure was 0.52 MPa in parallel orientation and 0.42 MPa in perpendicular orientation. At 1 MHz, the needed average peak negative pressure was 1.10 MPa in parallel orientation and 1.15 MPa in perpendicular orientation CONCLUSIONS: This first in-vitro study has demonstrated the feasibility of non-invasive HIFU to recanalize ureteral stents. This technology has a potential to reduce the need for ureteral stent exchange.

Natural progression of deep pelvic endometriosis in women who opt for expectant management

INTRODUCTION

The natural history of endometriosis is poorly understood, and despite numerous studies, the rate of the disease progression and optimal treatment planning in women who are asymptomatic or experience mild symptoms not requiring treatment are unknown. The aim of this study was to assess the behavior of deep endometriosis in women who are managed expectantly without any medical or surgical intervention.

MATERIAL AND METHODS

A retrospective cohort study of women diagnosed with deep endometriosis on transvaginal ultrasound scan at the Department of Gynecology, University College London Hospitals and The Gynecology Ultrasound Centre, London, UK, from April 2007 to April 2022. All women attended for at least two ultrasound scans which were carried out by a single expert ultrasound examiner and at least 6 months apart. The number and position of endometriotic nodules were recorded, and the mean diameter of each nodule was calculated from measurements taken in three orthogonal planes.

RESULTS

During the study period, 1922 women were found to have moderate or severe deep endometriosis on pelvic ultrasound examination. A total of 135 premenopausal women who were managed expectantly fitted the inclusion criteria. The median number of endometriotic nodules per woman at the initial visit was 2 (range: 0-7), and the median follow-up time was 666 days (181-2984). In the follow-up period, 50/135 women (37%, 95% CI: 29-46) developed additional nodules or experienced an increase in nodule size, and 17/135 women (13%, 95% CI: 8-19) had a regression in the number or size of the nodules. In the remaining 68/135 women (50%, 95% CI: 42-59) the disease remained static during the follow-up. The median change in mean diameter of nodules during the study period per woman was +0.13 mm (-11.67 - +5.83), with an annual growth rate of +0.09 mm/year (-6.65 - +6.45).

CONCLUSIONS

In our study we found evidence of deep endometriosis progression in just over a third of women. In view of this, asymptomatic or mildly symptomatic women diagnosed with deep endometriosis could be reassured that their disease is unlikely to worsen with time.

Visualization of sacral nerve roots and sacral plexus on gynecological transvaginal ultrasound: feasibility study

OBJECTIVE

To investigate the feasibility of identifying and measuring the normal sacral plexus (SP) on gynecological transvaginal ultrasound (TVS) examination.

METHODS

This was a prospective observational study conducted at a single tertiary gynecological referral center, including consecutive women undergoing TVS for various indications between November 2021 and January 2022. A standardized assessment of the pelvic organs was performed and the presence of any congenital or acquired uterine pathology or ovarian abnormality was recorded. Visualization of the right and left SP was attempted in all cases. The success rate and the time needed to identify the SP were recorded and measurements of the SP were made.

RESULTS

A total of 326 patients were included in the study. In all women, the SP was identified successfully on at least one side. SP were visualized bilaterally in 317 (97.2% (95% CI, 94.4-98.5%)) women. Only the right SP was seen in 3/326 (0.9% (95% CI, 0.2-2.7%)) and only the left in 6/326 (1.8% (95% CI, 0.6-4.0%)) (P = 0.5048). There was no significant difference in the median time required to visualize the right vs left SP (9.0 (interquartile range (IQR), 8.0-10.0) s  vs 9.0 (IQR, 8.0-10.0) s; P = 0.0770). The median transverse diameter of the right SP was 15.0 (IQR, 14.2-15.6) mm and that of the left SP was 14.9 (IQR, 14.4-15.6) mm.

CONCLUSIONS

We describe a novel method which allows for the consistent and rapid identification of the SP on TVS. Integrating assessment of the SP into routine pelvic TVS may be helpful particularly for women suffering from deep endometriosis. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Lesion-to-anal-verge distance in rectosigmoid endometriosis on transvaginal sonography vs magnetic resonance imaging: prospective study

OBJECTIVES

To compare transvaginal sonography (TVS) and magnetic resonance imaging (MRI) with intraoperative measurement (IOM) using a rectal probe in the estimation of the location of rectosigmoid endometriotic lesions, i.e. lesion-to-anal-verge distance (LAVD), and to compare two different MRI techniques for measuring LAVD.

METHODS

This was a prospective single-center observational study that included women undergoing surgery for symptomatic rectosigmoid endometriosis by discoid (DR) or segmental (SR) resection from December 2018 to December 2019. TVS and MRI were performed presurgically for each participant to evaluate LAVD, and the measurements on imaging were compared with IOM using a rectal probe. Clinically acceptable difference and limits of agreement (LoA) between TVS and MRI compared with IOM were set at ± 20 mm. Two different measuring methods for MRI, MRI_Center and MRI_Direct , were proposed and evaluated, as there is currently no guideline to describe deep endometriosis on MRI. Bland-Altman plots and LoA were used to assess agreement of TVS and both MRI methods with IOM. Systematic and proportional biases were assessed using paired t-test and Bland-Altman plots.

RESULTS

Seventy-five women were eligible for inclusion. Twenty-eight women were excluded, leaving 47 women for the analysis. Twenty-three DR and 26 SR procedures were performed, with both procedures performed in two women. The Bland-Altman plots showed that there were no systematic differences between TVS or MRI_Center when compared with IOM for all included participants. MRI_Direct systematically underestimated LAVD for lesions located further from the anal verge. TVS, MRI_Center and MRI_Direct had LoA outside the preset clinically acceptable difference when compared with IOM. LAVD was within the clinically acceptable difference from IOM of ± 20 mm in 70% (33/47) of women on TVS, 72% (34/47) of women on MRI_Center and 47% (22/47) of women on MRI_Direct .

CONCLUSIONS

TVS should be the preferred method to estimate the location of a rectosigmoid endometriotic lesion, i.e. LAVD, as it is more available, less expensive and has a similar accuracy to that of MRI. Estimating LAVD can be relevant for planning colorectal surgery for rectosigmoid endometriosis. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Effectiveness of ultrasound for endometriosis diagnosis

PURPOSE OF REVIEW

Endometriosis is a chronic benign gynaecological condition characterized by pelvic pain, subfertility and delay in diagnosis. There is an emerging philosophical shift from gold standard histopathological diagnosis through laparoscopy to establishing diagnosis through noninvasive imaging.

RECENT FINDINGS

The ENZIAN classification system was updated in 2021 to be suitable for both diagnostic imaging and laparoscopy. The accuracy of transvaginal ultrasound (TVUS) in diagnosing endometriosis varies depending on location of the lesion. A recent international pilot study found that when ultrasound is performed in accordance with the IDEA consensus, a higher detection of deep endometriosis is seen, with an overall sensitivity of 88% and specificity of 79% compared with direct surgical visualization.

SUMMARY

Although ultrasound can detect adenomyosis, deep endometriosis and endometriomas, it is not possible to reliably detect superficial endometriosis. In the instance of a negative ultrasound with persistence of symptoms despite medical therapy, laparoscopy should be considered for diagnosis and treatment.

Transvaginal ultrasound evaluation of the ureter

Objective

In this video, we present our technique for ureter assessment during pelvic ultrasound examination.

Methods

We used a GE Voluson E10 to perform transvaginal ultrasonography. These images were shared after thorough counselling, and obtaining informed consent from the patient. This video was edited using FinalCut ProX®.

Results

We systematized this routine after assessing the cervix, uterus, and adnexa. The vaginal probe was slightly removed to focus on the urethra. Next, we approached the hand on the contralateral thigh to the ureter. At this point, the probe was directed to the lateral pelvic wall where the ureteric orifice was found. Then, we raised our hands and perform an internal rotation movement to ascend the ureteral segments until it is related to the iliac vessels.

Conclusion

The urinary tract may be involved in gynecological pathologies. Transvaginal ultrasound is an easy, reproducible, and well-tolerated examination that can be used to evaluate the ureters below the pelvic brim.

Imaging of Endometriosis: The Role of Ultrasound and Magnetic Resonance

Endometriosis is a chronic gynecological disease characterized by the growth of functional ectopic endometrial glands and stroma outside the uterus. It causes pelvic pain, dysmenorrhea, dyspareunia, or infertility. Diagnosis requires a combination of clinical history, non-invasive and invasive techniques. The aim of the present review was to evaluate the contribution of imaging techniques, mainly transvaginal sonography and magnetic resonance imaging to diagnose different locations and for the most appropriate treatment planning. Endometriosis requires a multidisciplinary teamwork to manage these patients clinically and surgically.

Photoacoustic-Guided Laparoscopic and Open Hysterectomy Procedures Demonstrated With Human Cadavers

Hysterectomy (i.e., surgical removal of the uterus) requires severing the main blood supply to the uterus (i.e., the uterine arteries) while preserving the nearby, often overlapping, ureters. In this paper, we investigate dual-wavelength and audiovisual photoacoustic imaging-based approaches to visualize and differentiate the ureter from the uterine artery and to provide the real-time information needed to avoid accidental ureteral injuries during hysterectomies. Dual-wavelength 690/750 nm photoacoustic imaging was implemented during laparoscopic and open hysterectomies performed on human cadavers, with a custom display approach designed to visualize the ureter and uterine artery. The proximity of the surgical tool to the ureter was calculated and conveyed by tracking the surgical tool in photoacoustic images and mapping distance to auditory signals. The dual-wavelength display showed up to 10 dB contrast differences between the ureter and uterine artery at three separation distances (i.e., 4 mm, 5 mm, and 6 mm) during the open hysterectomy. During the laparoscopic hysterectomy, the ureter and uterine artery were visualized in the dual-wavelength image with up to 24 dB contrast differences. Distances between the ureter and the surgical tool ranged from 2.47 to 7.31 mm. These results are promising for the introduction of dual-wavelength photoacoustic imaging to differentiate the ureter from the uterine artery, estimate the position of the ureter relative to a surgical tool tip, map photoacoustic-based distance measurements to auditory signals, and ultimately guide hysterectomy procedures to reduce the risk of accidental ureteral injuries.

Ureter Visualization With Transvaginal Ultrasound: A Learning Curve Study

OBJECTIVES

To evaluate the learning curve of gynecologic surgical fellows (ie, in training) to properly identify the ureters in real time while simultaneously performing and interpreting transvaginal ultrasound (TVUS) examinations.

METHODS

We performed a prospective study, which took place at 2 centers in Sydney, Australia, from December 2017 to December 2018. Three fellows (F1-F3), of varying prestudy ultrasound (US) experience, were recruited to participate. One hundred fifty predetermined examinations were planned. A TVUS examination was performed by the study reference standard (an expert in gynecologic US). Subsequently, the fellows performed a focused component to identify bilateral ureters, 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 evaluations were complete. 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. One patient had a single ureter, and 1 patient had US evidence of hydroureter. The cumulative summation test for the learning curve for bilateral ureter identification showed that F1 did not reach competency by 50 TVUS examinations, whereas F2 and F3 required 41 and 31 TVUS examinations to reach competency, respectively.

CONCLUSIONS

Contrary to other studies on the topic, this study suggests that although it is feasible for surgical fellows to learn TVUS identification of bilateral ureters, not all fellows can reach competency during a program based on a predefined number of scans. We advocate for an individualized, competency-based medical education model in learning US for identifying the ureters.

Transvaginal Sonographic Imaging and Associated Techniques for Diagnosis of Ovarian, Deep Endometriosis, and Adenomyosis: A Comprehensive Review

Imaging of endometriosis and in particular deep endometriosis (DE) is crucial in the clinical management of women facing this debilitating condition. Transvaginal sonography (TVS) is the first-line imaging method and magnetic resonance imaging (MRI) may provide supplemental information. However, the delay in diagnosis of up to 10 years and more is of concern. This problem might be overcome by simple steps using imaging with emphasis on TVS and referral to tertiary care. Finally, TVS is crucial in mapping extent and location of disease in planning surgical therapy and counseling women regarding various therapeutic options. This review presents the available data on imaging of endometriosis with a focus on TVS and MRI for DE, adenomyosis, and ovarian endometriomas including endometriomas in pregnancy as well as the use of "soft markers." The review presents an approach that is in accordance with the International Deep Endometriosis Analysis (IDEA) group consensus statement.

Endometriosis and the Urinary Tract: From Diagnosis to Surgical Treatment

We aim to describe the diagnosis and surgical management of urinary tract endometriosis (UTE). We detail current diagnostic tools, including advanced transvaginal ultrasound, magnetic resonance imaging, and surgical diagnostic tools such as cystourethroscopy. While discussing surgical treatment options, we emphasize the importance of an interdisciplinary team for complex cases that involve the urinary tract. While bladder deep endometriosis (DE) is more straightforward in its surgical treatment, ureteral DE requires a high level of surgical skill. Specialists should be aware of the important entity of UTE, due to the serious health implications for women. When UTE exists, it is important to work within an interdisciplinary radiological and surgical team.

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.

Ultrasound Imaging in Endometriosis

Ultrasound examination is an indisputable imaging method in the diagnosis of endometriosis, as the first step in the detection, as the fundamental tool in planning the management, and as the best diagnostic instrument during surveillance of affected women. The aim of this article is to provide an update on the role of ultrasound in the detection, in the planning of medical and surgical treatment, and in the surveillance of patients with endometriosis.