Urinary tract obstruction: Ultrasound-guided intervention

Introduction

Urinary tract obstruction (UTO) is a common clinical problem of which there are many potential causes. The aim of this feature article is to explore the role of ultrasound in diagnosing UTO, during guided interventional procedures and the potential procedural complications.Topic description and discussion: Ultrasound is an integral imaging modality throughout the management pathway of a patient with UTO and is often utilised as a first-line test in diagnosis and treatment. Percutaneous nephrostomy is an interventional technique, usually performed by radiologists or interventional sonographers, as either a short- or long-term management strategy. It can either be used in isolation or to gain access to the renal collecting system prior to more complex interventional or surgical techniques. Ultrasound-guided interventional techniques to relieve UTO can be employed in a number of clinical scenarios each with their own indications, contraindications and complications.

Conclusion

Ultrasound plays a unique role in the planning and active stages of intervention with the provision of dynamic imaging which is crucial for providing safe and effective patient management.

Twelve tips for integrating ultrasound guided peripheral intravenous access clinical skills teaching into undergraduate medical education

Peripheral Intravenous access (PIV) is a procedure undertaken by Medical Practitioners and Non-Medical Practitioners. Traditional PIV uses a visual and tactile technique to locate blood vessels close to the surface of the skin. Chronic medical conditions, dehydration, obesity and recurrent intravenous access can make PIV challenging. Ultrasound (US) guided PIV is recommended to aid the identification of the arm arteries and veins and improve the success rate of needle placement in difficult cases. Medical and non-medical schools, and hospital organisations, are recognising the importance of US guided PIV education for undergraduate and postgraduate Medical and Non-Medical Practitioners. This to promote independence, efficiency and to improve patient safety. The aim of this 12 tips article is to highlight the considerations and practicalities of integrating and delivering, a practical based skills (PBS) session, on the use of US guided practice as an adjunct in difficult PIV, into the undergraduate medical education curricula.

Lung ultrasound education: simulation and hands-on

COVID-19 can cause damage to the lung, which can result in progressive respiratory failure and potential death. Chest radiography and CT are the imaging tools used to diagnose and monitor patients with COVID-19. Lung ultrasound (LUS) during COVID-19 is being used in some areas to aid decision-making and improve patient care. However, its increased use could help improve existing practice for patients with suspected COVID-19, or other lung disease. A limitation of LUS is that it requires practitioners with sufficient competence to ensure timely, safe, and diagnostic clinical/imaging assessments. This commentary discusses the role and governance of LUS during and beyond the COVID-19 pandemic, and how increased education and training in this discipline can be undertaken given the restrictions in imaging highly infectious patients. The use of simulation, although numerical methods or dedicated scan trainers, and machine learning algorithms could further improve the accuracy of LUS, whilst helping to reduce its learning curve for greater uptake in clinical practice.

The development of a pragmatic, clinically driven ultrasound curriculum in a UK medical school

Whether ultrasound (US) should be incorporated into a medical undergraduate curriculum remains a matter of debate within the medical education arena. There are clear potential benefits to its early introduction particularly with respect to the study of living anatomy and physiology in addition to the learning of clinical skills and procedures required for the graduate clinical practice. However, this needs to be balanced against what is perceived as an added value in addition to financial and time constraints which may potentially lead to the sacrifice of other aspects of the curriculum. Several medical schools have already reported their experiences of teaching US either as a standalone course or as a fully integrated vertical curriculum. This article describes and discusses the initial experience of a UK medical school that has taken the steps to develop its own pragmatic vertical US curriculum based on clinical endpoints with the intent of using US to enhance the learning experience of students and equipping them with the skills required for the safe practice as a junior doctor.

Epididymal Tuberculosis: A Diagnostic Challenge, Sonographic Findings, and Differential Diagnosis

A male patient was referred to radiology with scrotal pain and swelling. Prior to diagnosis, the patient had three sonograms for scrotal swelling, which progressed to a discharging scrotal sinus. At the second scan, a risk factor of past history of pulmonary tuberculosis (PTB) was noted. The first sonogram showed findings suggestive of left epididymitis, the second sonogram showed possible primary testicular tumor or epididymal tuberculosis (EPTB), the third sonogram showed epididymal pathology extending to involve the tunica vaginalis and scrotal wall leading to a sinus tract formation, and the fourth sonogram was normal. This case highlights the sonographic findings during progression of EPTB and the differential diagnosis to consider in such cases. It is a useful educational aid for radiologists and sonographers when evaluating the role of sonography in the management of a patient with scrotal swelling and discharging scrotal sinus.

Ultrasound probe grip: the afternoon tea technique

Background

Globally, ultrasound is being used to assist in central venous and difficult peripheral intravenous access in a variety of emergency and non-emergency clinical settings.

Context

After reading Flood's paper on safe central venous access and noting the difficulties clinicians find in probe stabilisation whilst performing dynamic intravenous access, we decided to share our teaching technique.

Innovation

The purpose of this correspondence is to highlight the 'afternoon tea technique' as a potential teaching method for probe stabilisation.

Implications

It is hoped that this technique will improve the image quality in dynamic procedures and increase the success rate of ultrasound-guided intravenous access in clinical practice.

Neonatal respiratory distress syndrome: Chest X-ray or lung ultrasound? A systematic review

BACKGROUND AND AIM

Neonatal respiratory distress syndrome is a leading cause of morbidity in preterm new-born babies (<37 weeks gestation age). The current diagnostic reference standard includes clinical testing and chest radiography with associated exposure to ionising radiation. The aim of this review was to compare the diagnostic accuracy of lung ultrasound against the reference standard in symptomatic neonates of ≤42 weeks gestation age.

METHODS

A systematic search of literature published between 1990 and 2016 identified 803 potentially relevant studies. Six studies met the review inclusion criteria and were retrieved for analysis. Quality assessment was performed before data extraction and meta-analysis.

RESULTS

Four prospective cohort studies and two case control studies included 480 neonates. All studies were of moderate methodological quality although heterogeneity was evident across the studies. The pooled sensitivity and specificity of lung ultrasound were 97% (95% confidence interval [CI] 94-99%) and 91% (CI: 86-95%) respectively. False positive diagnoses were made in 16 cases due to pneumonia (n = 8), transient tachypnoea (n = 3), pneumothorax (n = 1) and meconium aspiration syndrome (n = 1); the diagnoses of the remaining three false positive results were not specified. False negatives diagnoses occurred in nine cases, only two were specified as air-leak syndromes.

CONCLUSIONS

Lung ultrasound was highly sensitive for the detection of neonatal respiratory distress syndrome although there is potential to miss co-morbid air-leak syndromes. Further research into lung ultrasound diagnostic accuracy for neonatal air-leak syndrome and economic modelling for service integration is required before lung ultrasound can replace chest radiography as the imaging component of the reference standard.

Agreement between objective and subjective assessment of image quality in ultrasound abdominal aortic aneurism screening

OBJECTIVE

To investigate agreement between objective and subjective assessment of image quality of ultrasound scanners used for abdominal aortic aneurysm (AAA) screening.

METHODS

Nine ultrasound scanners were used to acquire longitudinal and transverse images of the abdominal aorta. 100 images were acquired per scanner from which 5 longitudinal and 5 transverse images were randomly selected. 33 practitioners scored 90 images blinded to the scanner type and subject characteristics and were required to state whether or not the images were of adequate diagnostic quality. Odds ratios were used to rank the subjective image quality of the scanners. For objective testing, three standard test objects were used to assess penetration and resolution and used to rank the scanners.

RESULTS

The subjective diagnostic image quality was ten times greater for the highest ranked scanner than for the lowest ranked scanner. It was greater at depths of <5.0 cm (odds ratio, 6.69; 95% confidence interval, 3.56, 12.57) than at depths of 15.1-20.0 cm. There was a larger range of odds ratios for transverse images than for longitudinal images. No relationship was seen between subjective scanner rankings and test object scores.

CONCLUSION

Large variation was seen in the image quality when evaluated both subjectively and objectively. OBJECTIVE scores did not predict subjective scanner rankings. Further work is needed to investigate the utility of both subjective and objective image quality measurements.

ADVANCES IN KNOWLEDGE

Ratings of clinical image quality and image quality measured using test objects did not agree, even in the limited scenario of AAA screening.

Reliability of aortic aneurysm screening measurements

The aim of this feasibility study was to assess the impact that image processing of abdominal aortic ultrasound (US) images had on the intra-observer reliability of the diameter measurement. The study compared variability between inner-to-inner (ITI), outer-to-outer (OTO) and outer-to-inner (OTI) wall diameter measurements and their resilience to image processing. Three US images of transverse abdominal aortas were manipulated in 13 different ways using functions from Image J software (National Institutes of Health, Bethesda, MD, USA). Blinded measurements were performed of the aortic diameters from each image; this was repeated for ITI, OTO and OTI. Profiles of each image were produced and sets of rules developed to provide detailed instructions as to where, on the profile, the callipers should be placed to correspond with the actual image. The reliability of the diameter measurements compared to the original diameter measurement was least affected by adjusting the brightness and contrast of the US images (better than ± 1.5 mm). Using the functions 'Sharpen' and 'Find Edges' created the largest difference (up to -5 mm). The ITI measurements had the widest spread of variability, whereas the OTI measurements proved to be the most repeatable and resilient to image processing. This study suggests the precision of the measurements can be kept within satisfactory levels even after image manipulation. It also showed the most reliable measuring guideline was OTI, in contrast to the guideline currently used by the NHS Abdominal Aortic Aneurysm Screening Programme. Further research is needed to transfer the findings into the clinical setting of the National Screening Programme to increase its reliability.

Comparison of two- and three-dimensional transvaginal ultrasound in the visualisation of intrauterine devices

The aims of the study were to evaluate whether three-dimensional transvaginal ultrasound (3D TV US) is superior to two-dimensional transvaginal ultrasound (2D TV US) at visualising intrauterine devices and determining their position. This prospective study included 52 participants with an intrauterine device fitted, who underwent 2D TV US and 3D TV US. 2D TV US and 3D-reconstructed coronal images were reviewed by two gynaecological radiologists to assess ease of visualisation and position of the intrauterine devices. Statistical analysis was performed using Wilcoxon signed-rank, McNemar and Chi-squared tests. The inter-observer agreement was measured using Cohen's Kappa. Intrauterine device visualisation scores were significantly higher with 2D TV US compared with 3D TV US (Radiologist 1 p = <0.001, Radiologist 2 p = 0.007). A significant number of T-arms appeared to perforate into the adjacent myometrium on the 3D-reconstructed coronal image, but were normal on the 2D images (Radiologist 1 p = <0.001, Radiologist 2 p = 0.008). Radiologist 1 found 19 perforated T-arms on 3D TV US compared with four on 2D TV US. Radiologist 2 found 13 perforated T-arms on 3D TV US compared with five on 2D TV US. Both radiologists agreed on the positions of the intrauterine devices substantially with 3D TV US (Kappa = 0.69) and moderately with 2D TV US (Kappa = 0.55). The 3D TV US did not visualise an intrauterine device better than 2D TV US. The 3D-reconstructed coronal image of the uterus can reliably display cases of T-arm perforation into the adjacent myometrium, which could be missed on 2D TV US images. The 3D TV US should be used in addition to 2D TV US in all cases where an intrauterine device is under evaluation.

Surveillance of Endovascular Aneurysm Repair: An Audit of Sonographer-Led Ultrasound and Radiologist-Led Computed Tomography Services

Objectives

Postoperative complications associated with endovascular aneurysm repair (EVAR) mandate the need for lifelong surveillance. The aim of this audit was to compare the detection rates of endoleaks during the first 10 months of a combined sonographer-led colour Doppler ultrasound (CDUS) and radiologist-led contrast-enhanced computed tomography (CECT), postoperative EVAR surveillance programme, within a single National Health Service Hospital.

Methods

A prospective audit was carried out of all patients with EVAR, who had same-day CECT and CDUS surveillance examinations between March 2010 and January 2011. CECT examinations were reported by three consultant vascular radiologists. Of 66 CDUS examinations, 64 (97%) were performed and reported by four certified vascular sonographers. The reports of dual-modality, same-day scans were compared, to establish agreement on the presence and classification of the type, or absence of endoleaks. CECT was used as the gold standard, against which the sensitivity and specificity of CDUS in endoleak detection was determined.

Results

Sixty-six paired same-day CECT and CDUS reports were compared. Ten endoleaks were identified by CECT (15% incidence) and eight (80%) of 10 were type II. The number of observed agreements was 58 (88%) of 66; CDUS missed six endoleaks (five type II) and suggested two false-positives. CDUS had a sensitivity of 40% and a specificity of 96%. Conclusions: In our study, CDUS demonstrated an excellent specificity but had a low sensitivity for endoleak detection. We agree CDUS cannot effectively replace CECT as the sole imaging modality. Research to determine an international consensus for an effective and efficient postoperative EVAR surveillance patient pathway is required.

A workforce review in diagnostic ultrasound

Current ultrasound education for sonographers is at post-graduate level and it is a service expectation that sonographers are equipped with advanced skills on qualification. The aim of the working party review was to assess the current roles and responsibilities of the sonographers, with a view to determining whether there was an opportunity to introduce a lower band practitioner role within the local hospital ultrasound department as well as the wider ultrasound community. Qualitative data, for the review, were obtained from two sources: (i) a local working party consisting of two ultrasound managers, two sonographers, one consultant radiologist, one line manager and one lecturer in diagnostic imaging and (ii) radiologists of the local department, ultrasound colleagues within the Yorkshire and Humber Strategic Health Authority (SHA), local and national Higher Education Institute and Consortium for the Accreditation of Sonographic Education colleagues. The career structure of sonographers was reviewed with options to introduce a band 6 ultrasound practitioner post in the local radiology department. The level of work expected of sonographers within the local Trust demands advanced skills, currently recognized as Agenda for Change band 7, are utilized on a daily basis. Little opportunity for practitioners to work at a lower grade which would require only technical reports, with no diagnostic opinion, was identified. In conclusion, there is currently no scope for a band 6 ultrasound practitioner within the local radiology department. The review suggests there is a need for an ultrasound practitioner career structure, which is comparable with other professional groups. Such developments will require input and support from clinicians, radiologists, the professional body and the higher education institutions. The review recognizes the need for an ultrasound governance team within individual Trusts to oversee ultrasound provision, reporting and clinical developments.

Reproducibility of ultrasound measurement of the abdominal aorta

BACKGROUND

Abdominal aortic aneurysm (AAA) screening and surveillance programmes use ultrasound imaging to measure the anteroposterior (AP) diameter of the infrarenal aorta. The aim of this study was to examine potential observer bias and variability in ultrasound measurements.

METHODS

Studies were identified for review via a MEDLINE database search (1966-2009). References supplied in accessed papers were also checked for potential relevance. Consistent search terminology, and inclusion and exclusion criteria were used to ensure quality of data. Nine papers were available to review.

RESULTS

Variation in intraobserver repeatability and interobserver reproducibility was identified. Six studies reported intraobserver repeatability coefficients for AP aortic diameter measurements of 1·6-4·4 mm. These were below the 5-mm level regarded as acceptable by the UK and USA AAA screening programmes. Five studies had interobserver reproducibility below the level of 5 mm. Four studies, however, reported poor reproducibility (range from -2 to +5·2 to -10·5 to +10·4); these differences may have had a significant clinical impact on screening and surveillance.

CONCLUSION

The studies used different methodologies with no standardized measurement techniques. Measurements were taken by observers from different medical disciplines of varying grade and levels of training. Standard training and formal quality assurance of ultrasound measurements are important components of an effective AAA screening programme.

Ergonomically Auditing Your Scan Room

The growing demand for ultrasound examinations is evident, as is the incidence of work-related musculoskeletal disorders (WRMSDs) incurred by ultrasound practitioners. This paper outlines a simple ergonomic audit that all operators can complete on their ultrasound room and equipment. As a result of this audit, areas of weaknesses in room/equipment design can be highlighted, with recommendations for more ergonomically designed equipment put forward to departmental managers, with the overall aim of reducing WRMSDs among ultrasound practitioners.

The agreement between colour Doppler systems in measuring internal carotid artery peak systolic velocities

The study was undertaken to determine if the internal carotid artery peak systolic velocities (ICA PSVs) measured by two colour Doppler imaging systems (Acuson 128 and Siemens Quantum) agree sufficiently for the two systems to be interchangeable in evaluating carotid artery disease. One operator obtained blinded measurements of ICA PSV in 63 prospective nonrandomized patients at risk of stroke. The operator examined 20 patients in the first cohort to assess the intraobserver variation, and 43 patients in the second cohort to assess the limits of agreement between the systems. In vitro comparisons of the systems were also undertaken, using both string and flow phantoms. Excluding one outlier, the intraobserver reproducibility coefficient for both machines was 0.48 m s-1. The limits of agreement (within which 95% of differences lie) between systems were -0.47 to 0.45 m s-1. This reduced to -0.39 to 0.33 m s-1 when the one outlier was excluded. This is within the intraobserver reproducibility range. In vitro data show little intersystem variation with phantom velocity. Intratransducer differences increase when the Doppler angle is increased using the string phantom; maximum differences: Acuson 0.30 m s-1 (42%) and Siemens 0.32 m s-1 (32%). These are within the in vivo reproducibility range. Intratransducer difference decreases when the Doppler angle is increased using the flow phantom, maximum differences: Acuson 0.05 m s-1 and Siemens 0.07 m s-1. The results show the systems agree sufficiently to be interchangeable in evaluating carotid artery disease; however, errors in maximum PSVs, caused by operator or system variation, may lead to errors in percent stenosis grading of the carotid arteries.

Does the ultrasound diagnosis of low-lying placenta in early pregnancy warrant a repeat scan?

A retrospective analysis of 732 consecutive deliveries at this hospital was undertaken to see if the early (15-20 weeks) pregnancy ultrasound placental localisation was of value, and whether the diagnosis of low-lying placenta warranted a repeat scan. The placental site was reported as normal in 413 pregnancies, as low-lying in 79 and was not recorded in 240. None of the women with a low-lying placenta developed placenta praevia. There were no significant differences in pregnancy outcome between those women with a low-lying placenta and those in whom it was normally situated. The ultrasound diagnosis of low-lying placenta between 15 and 20 weeks gestation does not warrant a repeat scan.