Making Waves in Sonography Research | July 2022

Making waves

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EMERGING TECHNOLOGIES

Ensembled deep learning model outperforms human experts in diagnosing biliary atresia from sonographic gallbladder images

WHY THE STUDY WAS PERFORMED

Biliary atresia (BA) is a congenital disorder affecting intrahepatic and extrahepatic bile ducts. Affected infants present with jaundice, pale stools and dark urine. The exact cause is unknown. Early diagnosis is critical as early surgical intervention is required to achieve longterm transplant-free survival. Ultrasound is recommended as the initial diagnostic imaging tool although diagnosis is challenging. The use of artificial intelligence has the potential to help diagnose BA based on sonographic gallbladder images. The purpose of this study was to develop an ensembled deep learning model (*EDLM) to accurately identify BA and test the effectiveness against human experts. This model will aim to provide a solution to help in the diagnosis of BA, particularly in rural and underdeveloped regions where there is limited imaging expertise.

HOW THE STUDY WAS PERFORMED

The study used infants < 5 months with hyperbilirubinemia and suspected BA. All diagnoses were confirmed by laparoscopic cholangiography US guided cholecystocholangiography, liver biopsy or follow-up. After images were screened for suitability, 3705 gallbladder images were obtained from the principal hospital and 841 from the 6 collaborating external cohort. Retrospective and prospective sonographic images were used.

The EDLM was evaluated and compared to human experts using both internal and external validation cohorts. Images collected from smartphones and ultrasound videos was tested also for robustness. Specificity, sensitivity and accuracy for BA diagnosis was tested and compared.

The internal evaluation used a fivefold cross-validation manner on a training cohort that was partitioned into five subsets of an equivalent number of patients. Four of the subsets were used as a database to train the EDLM and the ensembled model then predicted the category of the remaining image. This process was repeated five times.

The external validation tested the effectiveness of EDLM with images from six other hospitals. This data was evaluated against the performance of three experts for accurate BA diagnosis. Diagnosis evaluation was also tested using smartphones that could be reliably used in a remote setting. This was done using an image per patient from the external validation database pictured by a smartphone in the region of the gallbladder and fed to the EDLM for intelligent diagnosis. Additionally, diagnosis using real-time ultrasound video was tested. An auto segmentation model was trained with a collection of 34 sonographic videos from 34 infants. The diagnostic performance of EDLM was compared to that of three human experts, each of whom independently made diagnoses by reviewing the videos and was blinded to other clinical information.

REVIEWED BY

Lisa McGuire

ASA SIG: Emerging technologies

REFERENCE

Authors: Wenying Zhou, Yang Yang, Cheng Yu, et al.

Journal: Nature Communications

Open Access: Yes

READ THE FULL ARTICLE HERE

*Ensembled deep learning model (EDLM)

The process of combining multiple learning algorithms to obtain their collective performance, this aims to improve performance.

Ensembled deep learning model outperforms human experts in diagnosing biliary atresia from sonographic gallbladder images continued

FLOW CHART OF STUDY

WHAT THE STUDY FOUND

In the internal evaluation, at both the image level and the patient level, the EDLM outperformed the two experts in diagnosing BA. AI achieved an accuracy level of 89.4% as opposed to the highest performing expert accuracy level of 87.4%. The accuracy level for AI and expert in the external evaluation results was very similar, achieving 87.6% and 87.8% respectively. However, the AI model achieved a higher sensitivity of 93.3% as opposed to 90% for the highest expert. Diagnosis based on smartphone images yielded an accuracy of 86.9%. The video data also achieved promising results for the AI model with an accuracy of 94.1%. Additionally, the prediction of the EDLM combined with human experts improved identification of BA. This study was conclusive in finding overall EDLM outperforms human experts in the diagnosis of BA.

RELEVANCE TO CLINICAL PRACTICE

These findings indicate EDLM can be used to help diagnose BA in both remote and hospital settings, improving diagnostic accuracy. This model is potentially deployable in multiple application scenarios, such as remote diagnosis when based on a smartphone app. EDLM is also helpful for the inexperienced radiologist in a hospital setting. Diagnosis based on combined predictions of human and AI further improves sensitivity even for expert radiologists. This model is predicted to be of particular benefit to those patients in underdeveloped regions without sufficient healthcare support.

“The ensembled deep learning model in this study [has the potential to] improve the diagnosis of biliary atresia in various clinical application scenarios, particularly in rural and underdeveloped regions with limited expertise.”

Fig 1. Flow chart of the study

REVIEWED BY Marilyn Zelesco ASA SIG: General

REFERENCE

Beyond appendicitis: ultrasound findings of acute bowel pathology

WHY THE ARTICLE WAS PUBLISHED

Bowel pathology is a common unexpected finding on routine abdominal and pelvic ultrasound. However, imaging staff are often unfamiliar with the ultrasound appearances of the gastrointestinal tract due to underutilisation of ultrasound for bowel investigations. This article reviewed basic ultrasound technique for bowel evaluation, ultrasound appearances of normal bowel and of common acute bowel pathologies.

INTRODUCTORY TEXT

The article introduced the reader to the concept that acute abdominal pain accounts for 8% of all emergency department presentations. Many of these will be due to underlying acute gut pathology. As ultrasound is often a first-line modality for investigation of acute abdominal pain, sonographers need to be familiar with characteristic features of abnormal bowel, such as wall thickening, decreased motility, absence of luminal content, and a fluid-filled distended lumen, all of which can be well demonstrated on ultrasound. However, a considered approach is required.

The article presents a comprehensive section on baseline bowel ultrasound technique, as well as a section on general bowel ultrasound principles and sonographic criteria. These general principles and criteria are well presented in a summation table that addresses wall stratification, wall thickness, luminal diameter, peristalsis, compressibility, vascularity and the involvement of adjacent fat.

CORE TEXT

The core text commences with consideration of the role of ultrasound in the diagnosis of acute appendicitis, including diagnostic pitfalls. The article then considers the role of ultrasound in infectious and pseudomembranous colitis. The article highlights that because the colonic wall is not well visualised sonographically, thickened wall almost always raises the suspicion for underlying colitis. Typhlitis is also discussed as it is a common presentation for neutropenic patients and those with other immunosuppressive disorders. The role of ultrasound in diverticulosis and diverticulitis (including Meckel’s diverticulitis) is covered, as well as potential complications such as obstruction, free air, abscess or fistula formation.

A large section of text addresses the exacerbation of Crohn’s disease – covering inflammation, fissures and fistulae, as well as strictures. Although there are findings in Crohn’s that demonstrate overlap with other diseases, the likelihood increases when the sonographer finds a segmental, circumferential bowel wall thickening that affects the terminal ileum along with evidence of complications such as abscess or fistula.

The authors then address bowel malignancy, lymphoma and colonic cancer as all of these may present as an acute finding.

The final section addresses characteristic features of small bowel obstruction on ultrasound, with an overall sensitivity of > 95% and accuracy of > 80% respectively. The authors highlight that the presence of free fluid between the small bowel loops suggests worsening mechanical small bowel obstruction and the need for surgical management.

RELEVANCE TO CLINICAL PRACTICE

Many sonographers/radiologists limit the use of abdominal and pelvic ultrasound to solid organs. However, ultrasound can be a valuable tool for the assessment of gut in the acute abdomen. This article familiarises the sonographer with basic normal and abnormal sonographic criteria – both static and dynamic assessment.

READ THE FULL ARTICLE HERE

Jihee Choe, Jeremy Wortman, Aya Michaels, Asha Sarma, Urvi Fulwadhva, Aaron Sodickson Emergency Radiology (2019) 26:307–317

“… familiarity of ultrasound features of the bowel along with a good understanding of ultrasound technique can facilitate early detection of bowel disease …”

HEALTH AND WELLBEING

A qualitative approach to understanding the effects of a caring relationship between the sonographer and patient

WHY THE STUDY WAS PERFORMED

The overarching purpose of this study was to investigate sonographers’ experiences of being caring professionals. This study was performed in response to the increasingly high demand for quality health services resulting in increasing stress among healthcare professionals managing high patient loads and negative and stressful work environments. This stress may correlate to objectifying patients as a coping mechanism to avoid compassion fatigue and burnout. The authors formulated guidelines to enhance caring relationships between sonographers and patients and to improve the psychological wellbeing of sonographers using a review of the literature and the results of this study.

HOW THE STUDY WAS PERFORMED

Registered, university trained sonographers working in private practices in Gauteng, South Africa were invited to participate and recruit other participants. There was a total of 14 participants, all female, from different cultural backgrounds, ages ranging from 27 to 42 years, with ultrasound experience of 3 to 16 years.

Between June and July 2018, four focus group interviews lasting for 20 to 60 minutes were conducted, each including 3 to 5 participants of the sample of 14 sonographers. The research question that formed the basis of the study was ‘Tell me about being a caring professional in sonography’. Data collection included full transcripts as well as documentation of non-verbal communication including body language and group dynamics. The researchers analysed the data, coding for themes and categories utilising a qualitative research methodology.

WHAT THE STUDY FOUND

The central theme present in the data was ‘The effects of a caring relationship between sonographer and patient’. Within this, three key categories were identified, including ‘professional pride, the protective mechanisms of the sonographer and the emotional and psychological strain of the sonographer’.

The study found that sonographers had a desire to be caring professionals while recognising that this caused both positive and negative experiences. The sonographers were proud of their profession and their ability to serve their patients, provide them with answers and make a difference in their patients’ lives. Protective mechanisms of the participants were identified, with participants attempting to find a balance between being compassionate and empathetic while also distancing and putting up protective barriers to avoid distressing emotional involvement and to maintain the ability to continue to meet the high demands of their duties as sonographers. The emotional strain of the participants was identified throughout the data collection, particularly with the experience of caring for patients with sad cases, while still professionally managing the workload. The researchers concluded the reported experiences of sonographers within this study were in line with current literature relating to mental health themes experienced by other healthcare professionals in general.

REVIEWED BY Julianne Barry

ASA SIG: Health and Wellbeing

REFERENCE

Authors: Leah Van Der Westhuizen, Kathleen Naidoo, Yasmin Casmod and Sibusiso Mdletshe

Journal: Journal of Medical Imaging and Radiation Sciences

Open Access: No

READ THE FULL ARTICLE HERE

A qualitative approach to understanding the effects of a caring relationship between the sonographer and patient continued

RELEVANCE TO CLINICAL PRACTICE

Based on this study, and a literature review, the researchers made the following recommendations.

1. Sonographers are encouraged to keep reflective journals documenting events that have affected them emotionally and formulating ideas on how best to manage future events to provide better care for themselves and their patients.

2. Regular peer discussions are recommended for sharing positive and negative experiences, practice strategies and to provide a sense of community and belonging.

3. Psychologist support should be available to all sonographers for assistance with emotional strain and burnout.

4. Giving sonographers access to breaks within the natural environment may enable sonographers to reduce their anxiety and stress levels and provide a higher quality of care to their patients.

“The study found that sonographers had a desire to be caring professionals while recognising that this caused both positive and negative experiences.”

VASCULAR

Point of care ultrasound screening for deep vein thrombosis in critically ill COVID-19 patients, an observational study

WHY THE STUDY WAS PERFORMED

Deep vein thrombosis (DVT) and the potentially lethal sequelae of pulmonary embolism (PE) are very real threats to those who are critically ill with COVID-19. The hallmark symptom of DVT –unilateral lower limb swelling – can often be hard to distinguish in the bedridden patient due to general states of stasis. As a result of this, referrals for evaluation of suspected DVT are often based on risk assessment scores and D-dimer tests, the efficacy of which have been and still are under debate. Duplex ultrasound is the preferred method in assessing for DVT; however, its sensitivity and specificity rely on the extensive training of skilled healthcare professionals who are not always available to perform this exam. This problem has only been compounded by the COVID-19 pandemic due to the potential for operator exposure and in-hospital contamination. This study explored the viability of screening for lower limb DVT in critically ill COVID-19 patients led by ICU medical residents performing an abbreviated study.

HOW THE STUDY WAS PERFORMED

Bilateral lower limb screening for DVT was performed on 56 eligible patients between April–July 2020. All subjects were ≥ 18 years old, had respiratory failure and tested positive for COVID-19. All DVT studies were performed by ICU medical residents recruited to a DVT screening program. They all received a 25-minute online video tutorial followed by a ‘hands-on’ session supervised by a physician verified in echocardiography but with limited experience in DVT studies. All scans consisted of either a two-compression (common femoral and popliteal veins) or extended compression protocol (includes superficial veins). Patients who had pathological findings on screening were referred for formal duplex DVT study.

WHAT THE STUDY FOUND

Seven ICU residents were recruited, of whom 2 had limited experience (10–20 scans), with the others having no experience at all. A median of 4 scans were performed per person at median day 3 after admission via 2-point compression (61%) and extended compression (39%) techniques. Four (7.1%) patients were positive for DVT on screening, 3 (5.4%) of which were confirmed by a formal DVT duplex examination. Two of the DVTs were localised in the popliteal vein. None of the 52 patients with a negative DVT screening result were diagnosed with DVT during follow-up.

RELEVANCE TO CLINICAL PRACTICE

As the authors of this article state, the small sample size and single-centre nature of this study make it hard to generalise its results across the board, especially when an incidence of DVT in critically ill COVID-19 patients has been reported at 10–23% elsewhere in the literature. What is relevant to the clinical practice of sonographers is the DVT screening itself. It is common knowledge that sonographers, particularly within the vascular subspecialty, are in short supply so it is understandable that a specialised sonographer can’t be assigned to an ICU unit to perform a DVT screening service. If this expertise is locally available, however, then perhaps the training of willing junior ICU doctors should be via sonographers and not by senior doctors who are proficient in an unrelated field of ultrasound and have only dabbled in lower limb studies. This could be a window of opportunity for professional ultrasound bodies like the ASA to devise a DVT screening curriculum for ICU personnel so that this essential diagnostic tool is performed with the highest degree of sensitivity and specificity.

REVIEWED BY Matt Adams

ASA SIG: Vascular REFERENCE

Authors: Sarah Galien, Michael Hulström, Miklós Lipcsey, Karl Stattin, Robert Frithiof, Jacob Rosén

Journal: Thrombosis Journal

Open Access: Yes

READ THE FULL ARTICLE HERE

During the COVID-19 pandemic, screening with CDUS would be limited by availability, expose ultrasound operators to infection and may increase in-hospital contamination

CARDIAC REVIEWED BY

Anthony Wald

ASA SIG: Cardiac

REFERENCE

Automated pattern recognition in wholecardiac cycle echocardiographic data: Capturing functional phenotypes with

the machine learning

WHY THE STUDY WAS PERFORMED

This study aimed to demonstrate the feasibility of applying machine learning (ML) to interrogate echocardiographic data from a whole cardiac cycle automatically. Primarily it was to recognise patterns in velocity profiles and deformation curves allowing the identification of functional phenotypes.

Pattern recognition in echocardiography is vital; tissue and blood flow Doppler reflect important patterns directly related to systolic and diastolic function. Each velocity profile can contain certain patterns specific to an underlying impairment. When these specific profiles are analysed, they can represent a ‘larger’ pattern that describes a patient phenotype.

Machine learning is being incorporated into echocardiography on an ongoing basis. Most approaches are centred around automated measurements of singular parameters such as left ventricular outflow tract velocity time integral or peak velocities across a valve. Whole cardiac cycle echocardiography data contains much information about cardiac function; by analysing the whole cardiac cycle, machine learning can capture patient similarities without being conditioned to a diagnostic label or clinical outcome.

The authors hypothesise that a machine learning workflow can automate data integration and pattern recognition from whole cardiac cycle echocardiography.

HOW THE STUDY WAS PERFORMED

Two hundred and eighty-six participants were enrolled in the study, 189 with hypertension and 97 without. All patients in the hypertensive cohort were asymptomatic and clinically managed.

Echocardiography was performed on the E9 or E95 echocardiography machines (GE Vingmed Ultrasound, Horton, Norway). Post imaging analysis was performed on EchoPAC, looking at longitudinal strain curves of the left ventricle. These were performed in the apical four-chamber view using an average of all six segments.

Deformation analysis of the left atrium was performed from the four-chamber and twochamber views. Left atrial reservoir, conduit and contractile function were evaluated by measuring the total systolic, early diastolic and late diastolic strain. The left atrial strain values were averaged across the four and two-chamber windows.

Deformation analysis, blood pool, Doppler tissue imaging velocity and all associated measurement profiles were semiautomatically analysed and acquired. In total, 1413 data points for every whole cardiac cycle of each participant were generated.

Multiple kernel unsupervised machine learning was used to integrate each data point per participant and position the patient in a virtual space representation of the echocardiographic characteristics. Regression and clustering analyses were performed to identify echocardiographic patterns present within the virtual space.

Authors: Filip Loncaric, MD, Pablo-Miki Marti Castellote, MSc, Sergio SanchezMartinez, PhD, Dora Fabijanovic, MD, Loredana Nunno, MD, Maria Mimbrero, MD, Laura Sanchis, MD, PhD, Adelina Doltra, MD, PhD, Silvia Montserrat, MD, PhD, Maja Cikes, MD, PhD, Fatima Crispi, PhD, Gema Piella, PhD, Marta Sitges, MD, PhD, and Bart Bijnens, PhD, Barcelona and Madrid, Spain; and Zagreb, Croatia

Journal: Journal of the American Society of Echocardiography

Open Access: No

READ THE FULL ARTICLE HERE

Automated pattern recognition in whole-cardiac cycle echocardiographic data: Capturing functional phenotypes with the machine learning continued

WHAT THE STUDY FOUND

This study showed the feasibility of using machine learning to automate the integration of tissue and blood flow Doppler obtained during a cardiac cycle to compose a comprehensive description of cardiac function. At the same time, it was automating the pattern recognition capability to recognise disease-related patient phenotypes.

RELEVANCE TO CLINICAL PRACTICE

Further research needs to be done to establish the prognostic value of this type of whole cardiac cycle assessment. This study did show the capability of machine learning to classify patients into a phenotype; however, the prognostic value of this practice needs to be studied further.

“Machine learning workflow can automate data integration and pattern recognition from whole cardiac cycle echocardiography”

PAEDIATRIC

2021 update on the urinary dilation (UTD) classification system: clarifications, review of the literature, and practical suggestions

WHY THE STUDY WAS PERFORMED

The aim of the paper was to look at the assessment of renal tract dilation. There is often a huge variability in recommendations for further imaging and follow-up of both fetus and children with urinary tract dilation. Trying to determine the management of these patients can be difficult. This is due to a wide range of clinical practices with how the US findings are reported. Historically there has not been uniformity in the definition or classification of the urinary tract system in both the pre and postnatal periods. This lack of correlation between the prenatal and postnatal US findings and the final urologic diagnosis has been problematic due to this lack of consensus.

WHAT THE PAPER LOOKED AT

The assessment of renal tract dilation has been challenging due to the different languages used between prenatal and postnatal care. A major benefit of UTD is the classification of a normal kidney, especially in infants. The main classification system that was being used previously was the SFU grading system in fetuses. The UTD classification system is a unified method of describing the urinary tract dilation in fetuses and infants using terminology that is common. The UTD classification system was initially introduced to promote research outcomes. Multiple studies have been done by different organisations looking at the UTD classification system reliability. By determining the best method of assessment, it allows improvement of outcomes of patients by ensuring the correct management pathway is determined.

WHAT THE STUDY FOUND

It found that by implementing the UTD classification system into reporting of both antenatal and postnatal care gives a more uniform management to patients. Research has indicated that after several years of initiating the UTD classification grading system, a better clinical outcome has been given. This is because there is better inter-rater reliability when compared to other classification systems. The UTD classification system intra-rater reliability remained the same for both the UTD and the SFU.

RELEVANCE TO CLINICAL PRACTICE

The main purpose of having a common language for renal dilation was to promote outcomes research, which was done. The research proved that by using the UTD classification it provides a uniform system to describe the antenatal and postnatal urinary tract dilation. There is also no cutoff age for using the UTD classification system; therefore, the goal being eventually to see it more widely adopted into different subspecialties to create a standardised management option that will ultimately optimise patient care.

REVIEWED BY

Leanne Lamborn

ASA SIG: Paediatric

REFERENCE

Authors: Hiep T Nguyen, Andrew Phelps, Brian Coley, Kassa Darge, Audrey Rhee, Jeanne S Chow

Journal: Pediatric Radiology (2022)

52:740–751

Open Access: No

READ THE FULL ARTICLE HERE

“[this study reviews] the clinical validation of the UTD classification system to provide credence for its use in managing fetuses and children with urinary tract dilation”

PAEDIATRIC

Implementation of bowel ultrasound practice for the diagnosis and management of necrotising enterocolitis

WHY THE STUDY WAS PERFORMED

Necrotising enterocolitis (NEC) is a serious inflammatory bowel disease with potentially devastating complications and is a leading cause of morbidity and mortality among premature infants. As bowel ultrasound (BUS) is a relatively new technique, there are some barriers which slow the implementation of these studies. These barriers include lack of education and training for sonographers, radiologists and clinicians and low case volume.

The aim of this paper is to provide a framework and a roadmap for work units to implement BUS in day-to-day practice for NEC diagnosis and management. It was written to highlight the advantages of BUS in the management of NEC and discuss the techniques used for this type of ultrasound study. It also aims to provide clear methods and examples to assist with implementation of the examination, interpretation of images and clear explanations of the clinical importance of the various findings on BUS for NEC.

WHAT THE PAPER LOOKED AT

The pathology and course of NEC was discussed and the potential to improve outcomes through timely management. Clinical examination and laboratory tests are not specific for the disease. Clinicians depend on abdominal X-rays (AXR) to aid in the diagnosis of NEC. However, AXRs have significant limitations in diagnosing NEC. Diagnosis of NEC can be made when pathognomonic signs such as portal venous gas and pneumatosis intestinalis are present.

The advantages of ultrasound over AXR are discussed. These include real-time assessment of peristalsis, vascular perfusion, bowel wall thickening/thinning/perforation, abdominal fluid, portal venous gas and pneumatosis.

BUS technique is discussed, including preparation (no preparation), equipment (both high and low frequency transducers for both superficial and deep imaging), and scanning technique. Different positioning is used to differentiate between pneumatosis and intraluminal gas. Colour Doppler is used to determine intestinal mural blood flows. Pneumoperitoneum, free fluid, bowel wall, bowel wall perfusion, pneumatosis and portal venous gas are all discussed at length. Limitations, including the fact that ultrasound is operator dependent, are discussed.

There are some excellent tables included in this article, which include: indications for ultrasound, representative protocol for sonographers and key findings and their relative clinical significance.

WHAT THE STUDY FOUND

BUS can be used to assess for and monitor NEC. Ultrasound can show early signs of NEC, as well as advanced signs of NEC, which include bowel wall thinning, absent bowel perfusion and absent peristalsis.

REVIEWED BY

Madonna Burnett

ASA SIG: Paediatric

REFERENCE

Authors: Karen M Alexander, Sherwin S Chan, Erin Opfer, Alain Cuna, Jason D Fraser, Shazia Sharif, Minesh Khashu

Journal: BMJ Journals (ADC Fetal and Neonatal edition)

Open Access: Yes

READ THE FULL ARTICLE HERE

PAEDIATRIC

Implementation of bowel ultrasound practice for the diagnosis and management of necrotising enterocolitis continued

Although bowel ultrasound provides more information than AXR in the evaluation of NEC, its overall sensitivity and negative predictive value is still relatively low.

Implementation of BUS within a unit should include input from all aspects of the infant’s care. The whole multidisciplinary team should be involved.

RELEVANCE TO CLINICAL PRACTICE

BUS can be used as an adjunct to AXR. The ultrasound findings can assist in guiding clinicians whether aggressive treatment such as surgery is warranted or conservative treatment will suffice. Although ultrasound cannot definitively rule out NEC, it can provide reassurance that no findings suggestive of NEC are present. This is helpful when an abdominal X-ray is equivocal.

Advantages of bowel ultrasound (BUS) over abdominal radiograph (AXR) in necrotising enterocolitis (NEC) include real-time assessment of the bowel, earlier diagnosis and earlier identification of ominous findings.

GYNAECOLOGY

Definition and sonographic reporting system for Cesarean scar pregnancy in early pregnancy: modified Delphi method

WHY THE STUDY WAS PERFORMED

Due to the ever-increasing number of deliveries by Caesarean section (CS), subsequent pregnancies may be at higher risk of caesarean scar pregnancy (CSP), placenta accrete spectrum (PAS) and other pathophysiological processes with high morbidity and mortality. These guidelines were developed to provide a standardised approach for the evaluation and reporting in the first trimester of CSP for both expert and general sonographic providers as no universally accepted reporting system existed.

HOW THE STUDY WAS PERFORMED

A modified Delphi procedure was conducted with repeated rounds of questionnaires derived from the available literature and presented to experts, analysed and re-presented in multiple rounds until a consensus was achieved. PubMed and EMBASE databases were searched with strict criteria relating to the research question and if the literature defined or evaluated a CSP by ultrasound. The experts included obstetric and gynaecological clinicians with advanced ultrasound experience. Twenty-eight experts were invited; however, only 16 participated in the Delphi study. The data collection ran from July 2018 to August 2020 and included four rounds of online questions and one face-to-face meeting with 62.5% participation. Responses were anonymised and consensus was achieved for all 58 items.

WHAT THE STUDY FOUND

• The optimal gestational age (GA) for the assessment of CSP, including localisation of the gestational sac (GS) and placenta is 6–7 weeks; however, the recommendations apply to gestations up to 12 weeks.

• CSP includes all pregnancies (GS/placenta) with implantation in close contact or within the niche, while a pregnancy near the CS/niche but not in contact is classified as low implanted pregnancy. Further description of the CSP depended on the GS crossing two imaginary lines, agreed upon by the panel as the uterine cavity line and/or serosal line. Multiple images and representative schematic drawings are provided to assist in the definition and description.

• In the case of CSP, measurement (2D) of the residual myometrial thickness (RMT) and adjacent myometrial thickness (AMT) in sagittal place were determined to be useful; however, measurement of the niche was deemed irrelevant.

• Colour Doppler imaging (CDI) assisted in the evaluation of trophoblastic invasion and CSP identification as well as in the presence of CSP, CDI could assist in differentiation between low implantation pregnancy or miscarriage. CDI is essential in identifying retained placental tissue with the ability to differentiate from other uterine anomalies and haemorrhage.

• A flow chart is provided to guide sonographers in differentiating between three important clinical presentations: CSP, cervical pregnancy and miscarriage.

REVIEWED BY

Jennifer Alphonse PhD

ASA SIG: Gynaecology

REFERENCE

Authors: IPM Jordans, C Verberkt, RA de Leeuw, CM Bilardo, T van den Bosch, T Bourne, HAM Brölmann, M Dueholm, WJK Hehenkamp, N Jastrow, D Jurkovic, A Kaelin Agten, R Mashiach, O Naji, E Pajkrt, D Timmerman, O Vikhareva, LF van der Voet, JAF Huirne

Journal: Ultrasound in Obstetrics and Gynecology

Open Access: Yes

READ THE FULL ARTICLE HERE

Definition and sonographic reporting system for Cesarean scar pregnancy in early pregnancy: modified Delphi method continued

RELEVANCE TO CLINICAL PRACTICE

There are clear criteria provided for both basic and advanced evaluation of CSP with tables and figures providing visual support, enhancing the readability and assisting in clinical application.

The schematic diagrams, accompanied by ultrasound images, are of enormous benefit. When in any doubt of the position of the GS/placenta in relation to the CS, referral to an expert clinic is recommended over MRI, as MRI was deemed to be of no value in the assessment of CSP.

“Using a modified Delphi procedure [the authors] have generated a standardized sonographic evaluation and reporting system for Cesarean scar pregnancy in the first trimester, with specific recommendations for assessment in general practice and in expert clinics.”

GYNAECOLOGY

Transvaginal sonography determines accurately extent of infiltration of rectosigmoid deep endometriosis

WHY THE STUDY WAS PERFORMED

The study by Aas-Eng et al. investigated whether there is correlation between the transvaginal ultrasound presurgical measurement of rectosigmoid deep endometrial lesions and postsurgical specimen measurement. Transvaginal ultrasound is a well-established method for the diagnosis of deep endometriosis with both high sensitivity and specificity. Endometrial lesions are seen as a hypoechoic thickening or hypoechoic nodule typically affecting the muscularis layer of the bowel wall. Assessment with transvaginal ultrasound is part of the multidisciplinary approach taken when planning deep endometrial surgical procedures. Transvaginal ultrasound plays an important role in the optimal preoperative assessment for patients as the degree of rectosigmoid deep endometriosis may be measured and described. This study aimed to assess the accuracy of transvaginal ultrasound measurement of deep rectosigmoid endometrial lesions when compared with postsurgical specimen measurement.

HOW THE STUDY WAS PERFORMED

A prospective observational methodology was used to investigate correlation between pre and postsurgical measurements. One hundred and sixty-six women scheduled for discoid resection or segmental resection were recruited from three tertiary referral centres in Austria, Norway and Australia. Participants underwent transvaginal ultrasound followed by discoid resection or segmental resection for rectosigmoid deep endometriosis.

Rectosigmoid deep endometriosis was measured using transvaginal ultrasound in all three diameters as recommended by the International Deep Endometriosis Analysis group. Length and anteroposterior thickness were measured in the midsagittal plane. The transverse diameter was then obtained after turning the probe transverse at the level of the lesions maximum thickness in its midsagittal plane. Scans were performed by gynaecological surgeons who were experienced in transvaginal ultrasound examination. Postsurgical measurement of lesions was undertaken using a ruler. The length, thickness and transverse diameter of specimens were measured after cutting the specimen in the midsagittal plane. A variety of statistical analysis tools were used to examine the difference between and correlation in measurement between presurgical transvaginal assessment and postsurgical specimen size.

WHAT THE STUDY FOUND

This study found good agreement between transvaginal ultrasound and postsurgical specimen for lesion length measurement. Aas-Eng et al. demonstrated that transvaginal ultrasound length measurements were reliable and correlated well with postsurgical specimen length measurements. There was a greater discrepancy seen in the measurement of deep endometrial lesion thickness and diameter. Measurement of the thickness of deep endometrial lesions on transvaginal ultrasound compared to surgical specimens had only moderate to good reliability and correlation. Measurement of lesion diameter did not correlate

REVIEWED BY

Gina Humphries

ASA SIG: Gynaecology

REFERENCE

Authors: Aas-Eng MK, Lieng M, Dauser B, Diep LM, Leonardi M, Condous G, Hudelist G

Journal: Ultrasound Obstet Gynecol. 2021 Dec;58(6):933–939

READ THE FULL ARTICLE HERE

GYNAECOLOGY

Transvaginal sonography determines accurately extent of infiltration of rectosigmoid deep endometriosis continued

well having only a poor to moderate reliability when comparing the transvaginal ultrasound measurements to the postsurgical measurements.

Discrepancies in measurements may be due to variations in surgical cuts. There is also difficulty in identifying the infiltration depth of rectosigmoid deep endometriosis on transvaginal ultrasound.

Despite these limitations, Aas-Eng et al. demonstrate a clear value in using transvaginal ultrasound for measuring the length of rectosigmoid deep endometriosis prior to surgery.

RELEVANCE TO CLINICAL PRACTICE

Aas-Eng et al. have demonstrated that systemic measurement of rectosigmoid deep endometriosis with transvaginal ultrasound provides accurate assessment of the length of rectosigmoid lesions. Therefore, transvaginal ultrasound plays a vital role in surgical planning and risk assessment for optimising patient outcomes.

“In women with rectosigmoid deep endometriosis, transvaginal ultrasound is reliable for assessing lesion length but less reliable for lesion thickness and transverse diameter measurements”

OBSTETRICS

WHY THE STUDY WAS PERFORMED

As no international consensus on the ultrasound assessment of lymph nodes in any anatomical location existed, in 2016 the Valvular International Tumor Analysis (VITA) group was formed with the aim to provide inguinal lymph nodes description, measurement technique, terminology and examination technique in women with vulvar cancer. The nomenclature suggested could also be applied to lymph nodes in other superficial areas of the body, or deep lymph nodes where patient habitus and ultrasound technology permit high resolution assessment. It should be noted that an agreement between ultrasound features and histopathological diagnosis has not yet been established; however, the group hopes that this consensus statement will encourage prospective research for the identification of ultrasound features typical of lymph node metastases and a standardised approach to ultrasound examination, description and reporting.

HOW THE STUDY WAS PERFORMED

Inguinal lymph nodes should be examined utilising a high frequency linear array transducer (7.5–14 MHz). Systematic assessment of the femoral triangle is essential by sonographers with anatomical knowledge of the region. The paper describes the ultrasound landmarks that designate the boundaries of the femoral triangle, which include the inguinal ligament, adductor longus muscle and the sartorius muscle, detailed in Appendix S3 with tips and tricks in Appendix S4.

The patient is positioned supine with legs extended and apart. The ultrasound assessment begins at the apex of the femoral triangle with the transducer in transverse, moving cranially and slowly. Gentle pressure is recommended as compression of the femoral vein will affect orientation. Assessment continues until the inguinal ligament is reached. This assessment establishes the region of interest following with the assessment of the lymph nodes performed in both transverse and longitudinal planes. High magnification and resolution are maintained throughout scanning and should include surrounding perinodal tissues to assess grouping.

Lymph nodes are examined utilising both quantitative (measurement) and qualitative (description) parameters. A normal lymph node has regular contours, is oval in shape, and when measured in two planes has a long-axis-to-short-axis ratio (L/S ratio) > 2. Other measurements include cortical-thickness-to-medullar-thickness ratio (C/M) and maximumcortical-thickness-to-minimum-cortical-thickness ratio (Cmax/Cmin), which are both described in detail.

Qualitatively, dominant characteristics should be the focus of the assessment rather than the minute changes. The medulla is central and hyperechogenic while the cortex is continuous and hypoechoic with a thin echogenic capsule. There is an echogenic hilum interrupting the cortex which contains a blood vessel that passes from the adjacent perinodal tissue to the medulla. On colour Doppler imaging (CDI) branches may be seen within the medullar.

REVIEWED BY

Jennifer Alphonse PhD

ASA SIG: Obstetrics

REFERENCE

Authors: D Fischerova, G Garganese, H Reina, SM Fragomeni, D Cibula, O Nanka, T Rettenbacher, AC Testa, E Epstein, I Guiggi, F Frühauf, G Manego, G Scambia and l Valentin

Journal: Ultrasound in Obstetrics and Gynecology

Open Access: Yes

READ THE FULL ARTICLE HERE

Terms, definitions and measurements to describe sonographic features of lymph nodes: consensus opinion from the Valvular International Tumor Analysis (VITA) group

OBSTETRICS

Terms, definitions and measurements to describe sonographic features of lymph nodes: consensus opinion from the Valvular International Tumor Analysis (VITA) group continued

Other lymph node classifications covered by this article include reactive lymph nodes, postreactive lymph nodes and metastatic lymph nodes, all with detailed descriptions, schematic diagrams and ultrasound images with both 2D and CDI.

WHAT THE STUDY FOUND

As there are no internationally accepted standardised terms to describe the ultrasound appearance of lymph nodes regardless of the anatomical position, it is difficult to compare the results from different ultrasound studies. As terms are non-standardised, the ultrasound characteristics of lymph nodes infiltrated by cancer or lymphoma are unable to be compared ultrasonically from metastatic lymph nodes from primary cancer. Further, the normal appearance of head and neck, axillary and inguinal lymph nodes differ ultrasonically.

Standardised examination techniques and terminology are needed and correlation with histopathological diagnosis is essential.

RELEVANCE TO CLINICAL PRACTICE

This is not a definitive document, and based on the quality of future research, it will continually be adjusted. However, as lymph node assessment and ultrasound description in clinical practice vary greatly, this paper may assist in a more standardised approach to ultrasound assessment, description and reporting of lymph nodes.

“In gynaecologic oncology centers with available ultrasound expertise, ultrasound alone is the method of choice for preoperative assessment of inguinal lymph nodes, [however] the lack of standardized ultrasound nomenclature to describe lymph nodes makes it difficult to compare results from different ultrasound studies and to find reliable ultrasound features for distinguishing non-infiltrated lymph nodes from lymph nodes infiltrated by cancer.”

OBSTETRICS

Role of Doppler ultrasound at time of diagnosis of late-onset fetal growth restriction in predicting adverse perinatal outcome: prospective cohort study

WHY THE STUDY WAS PERFORMED

There are numerous research studies conducted on early-onset fetal growth restriction (FGR); however, the diagnosis of late-onset FGR is equally important due to the increased risk of short-term and long-term morbidities when compared to normally grown fetuses. Late-onset growth restriction is defined as growth restriction diagnosed after gestational age of 32 weeks (K32). It is challenging to diagnose late-onset FGR as the tools we rely upon are fetal growth scan with Doppler assessments, which often include fetal umbilical artery (UA) Doppler, fetal middle cerebral artery (MCA) pulsatility index (PI), cerebroplacental ratio (CPR), umbilical vein (UV) Doppler, maternal uterine arteries Doppler, etc., as well as amniotic fluid assessment. Unlike early-onset FGR whereby fetal UA Doppler is useful in diagnosing, fetal UA Doppler is usually normal in late-onset FGR. Thus the study suggested the importance of utilising other Doppler indices to aid in the diagnosis of late-onset FGR.

There are two main aims for this study, with the primary aim of exploring the strength of association between fetoplacental Doppler indices at the time of diagnosis of late-onset FGR and adverse perinatal outcome, including their predictive accuracy. The secondary aim was to evaluate whether a multiparametric diagnostic model improved the diagnostic ability of Doppler ultrasound in detecting adverse perinatal outcomes in pregnancies affected by lateonset FGR.

HOW THE STUDY WAS PERFORMED

This is a prospective study conducted at Cristo Re Hospital in Rome, Italy, in the Division of Maternal Fetal Medicine over a period of one year and three months (October 2017 –December 2018).

The study population consists of singleton pregnancies complicated by late-onset FGR, with a definition of ultrasound estimated fetal weight (EFW) or abdominal circumference (AC) < 3rd percentile using local population charts, or EFW or AC < 10th percentile with UA-PI > 95th percentile or CPR < 5th percentile. The exclusion criteria are pregnancies with FGR diagnosed before K32, as well as pregnancies complicated by congenital infections, chromosomal anomalies or structural anomalies.

The ultrasound scans were conducted by two experienced sonographers, whereby EFW and amniotic fluid (deepest vertical pocket without fetal parts or umbilical cords) were recorded, as well as the following Doppler indices measured:

• Fetal UA Doppler PI (free floating loop)

• Fetal MCA Doppler (at the origin from the circle of Willis in the axial plane)

• Fetal UV blood flow (UVBF) Doppler (from the intra-abdominal portion using automated trace of at least three consecutive waveforms or 10s for UVBF)

• Mean PI of both maternal uterine arteries (measured at the crossover with the external iliac artery).

REVIEWED BY

Ling Lee

ASA SIG: Obstetrics

REFERENCE

Authors: G Rizzo, I Mappa, V Bitsadze, M Słodki, J Khizroeva, A MakatsariyA and F D’Antoni

Journal: Ultrasound Obstet Gynecol 2020; 55:793–798. DOI: 10.1002/uog.20406

READ THE FULL ARTICLE HERE

Role of Doppler ultrasound at time of diagnosis of late-onset fetal growth restriction in predicting adverse perinatal outcome: prospective cohort study continued

Additional Doppler index such as umbilical vein blood flow normalised for fetal abdominal circumference (UVBF/AC) was also included. UVBF/AC is the absolute value of UV blood flow corrected for fetal size.

Since fetal Doppler indices change with gestational age (GA), the study transformed the obtained Doppler indices into Z-scores (calculated using the formula: observed value –expected value for GA/standard deviation for GA).

The purpose of the ultrasound examination is to detect the occurrence of adverse perinatal outcomes in pregnancies affected by late onset FGR and its accuracy, which is called composite adverse perinatal outcome (CAPO), including at least one of the following:

• Emergency caesarean section for fetal distress

• 5 minutes Apgar score < 7

• Umbilical artery pH < 7.10

• Neonatal admission to special care unit.

Pregnancies that were diagnosed with late onset FGR were managed by obstetricians who were blinded from the Doppler data obtained by the research study, except UA-PI. These pregnancies were managed according to local protocol, such as weekly or fortnightly clinical evaluation, fortnightly fetal growth assessment, etc. In the case of pregnancies complicated by maternal medical conditions (pre-eclampsia, gestational hypertension), reduced amniotic fluid, reduced fetal movement, further decline in fetal growth and pregnancies beyond gestational age of 39 weeks, induction of labour was warranted immediately.

WHAT THE STUDY FOUND

The study has a total of 261 pregnancies complicated by late-onset FGR; 18 cases were excluded with incomplete data, and the remaining 243 pregnancies were analysed, whereby CAPO happened in 32.5% of cases. The highest occurrence CAPO was emergency caesarean sections for fetal distress (74.5%). Mean GA at delivery and birth weight were found to be lower in the pregnancies complicated by CAPO.

The result focused on comparing the Z-scores of the Doppler indices between pregnancies complicated by CAPO and those without. Z-scores of mean MCA-PI, CPR and UVBF/AC were lower for pregnancies with CAPO, except for Z-scores of mean maternal uterine artery PI, which was higher. No significant difference between the two groups in fetal EFW, amniotic fluid and UA-PI. Z-scores of mean maternal uterine artery PI, CPR and UVBF/AC were associated independently of CAPO but GA at delivery and birth weight were not.

For the secondary aim of the study, the study went on to analyse the performance of the various Doppler indices in predicting CAPO in pregnancies affected by late-onset FGR. The area under receiver operating characteristic curve (AUC) of Doppler parameters was generated. Using these parameters, the study found that UVBF/AC Z-score had an AUC of 0.723, which had better accuracy compared to mean maternal uterine artery PI Z-score and CPR Z-score (whereby both were poor in predicting). When combining all three Z-scores, the AUC was 0.745, which showed better accuracy.

“Assessment of umbilical vein blood flow (more precisely the UVBF/AC), at the time of diagnosis of late-onset fetal growth restriction may play a role in identifying pregnancies at higher risk of morbidity.”

Role of Doppler ultrasound at time of diagnosis of late-onset fetal growth restriction in predicting adverse perinatal outcome: prospective cohort study continued

STRENGTHS AND LIMITATIONS OF THE STUDY

The strength of the study was its large sample size, conducting in a prospective approach, inclusion of cases only affected by late-onset FGR, and the attending obstetricians were blinded to the Doppler findings (except UA Doppler).

The limitation of the study was the ultrasound Doppler assessment was only conducted once at the time of diagnosis without continuous documentation of the Doppler changes in the affected pregnancies from the time of diagnosis to delivery.

RELEVANCE TO CLINICAL PRACTICE

At the beginning, the study had stated the difficulty in detecting and diagnosing pregnancies affected by late-onset FGR. From previous studies, the readers were informed that UA-PI was usually normal in fetuses with late-onset FGR and therefore unreliable in detecting the condition.

The readers were also informed that low PI in MCA or CPR was known to be associated with abnormal acid-base status (which could cause fetal hypoxemia and acidemia) and admission to the neonatal unit, while increased resistance in maternal uterine arteries was associated with caesarean sections for fetal distress.

This study highlighted the potential of using the umbilical vein blood flow, more precisely the UVBF/AC, to improve the detection of late-onset FGR and the prediction of pregnancies affected by adverse perinatal outcomes, defined as CAPO by the authors. The study also achieved its secondary aim by suggesting that a multiparametric diagnosis model (UVBF/ AC Z-score, mean uterine artery PI Z-score and CPR Z-score) offered a higher accuracy in predicting CAPO.

The authors concluded with future studies to further evaluate the usefulness of UVBF/AC as a standalone predictor for CAPO by acknowledging the difficulty in obtaining accurate UVBF. Furthermore, the authors suggested more studies are required to build a multiparametric model by including the assessment of UVBF, maternal uterine arteries and other pregnancy characteristics to predict CAPO.

“Unlike early-onset FGR whereby fetal UA Doppler is useful in diagnosing, fetal UA Doppler is usually normal in late-onset FGR.”