Stephen Wolstenhulme

Reproducibility of ultrasound measurement of the abdominal aorta

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.

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.

Is there agreement on what makes a good ultrasound image

With the introduction of national guidelines for ultrasound screening it might be assumed that there is agreement in the key features required in assessing image quality. The aim of this study was to determine whether it is possible that personal preferences may influence what is regarded as an acceptable image. Two image sets, one vascular and one obstetric, were taken to the British Medical Ultrasound Society ‘Ultrasound 2012’ conference for delegates to rate whether images were acceptable or not. Data collection took place on days one and two, with the results presented on day three of the conference. Images from a variety of ultrasound machines were used and ranked in order of the odds of producing an acceptable image using logistic regression. Agreement between observers was investigated and three images per person were repeated to look at agreement within observers. Audience feedback was used to record the reasons why images were regarded as acceptable or not. Eighty-two participants reviewed each of the two image sets. The machine rankings revealed that some machines were up to 12 times more likely to produce an acceptable image than other machines. Agreement amongst experts or non-experts was found, but disagreement between the subgroups of experts and non-experts. Agreement within observers was around 80% and similar results were found in each of the image sets. Despite image quality assessment, personal preferences and expertise may still affect judgement, and guidelines may not ensure agreement.

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.

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.

Is there a co-association between renal or retroperitoneal tumours and scrotal varicoceles? A systematic review

Scrotal varicoceles, which are relatively common, are sometimes caused by venous flow disturbance resulting from a renal or retroperitoneal tumour. Consequently, it is common practice to perform extended renal and retroperitoneal scans following varicocele identification. The aim of this systematic review was to determine the extent of the co-association between renal or retroperitoneal tumours and scrotal varicoceles using primary research literature. We conducted a search of 11 electronic databases; hand-searched five relevant textbooks; and conducted forward- and backward-citation searches of included articles. Articles that were included were assessed for research quality and data extracted. Twenty-four articles were found, comprising 19 case reports and five case series, reporting 35 cases in total. All cases had both a varicocele and a tumour (renal, retroperitoneal or other). We found no cohort or case–control studies. In conclusion, case reports and case series are susceptible to significant publication bias and the lack of any cohort or case–control studies meant that it was not possible to establish the extent of the co-association between renal or retroperitoneal tumours and scrotal varicoceles. It was not possible to estimate the value of conducting an extended scan in patients with scrotal varicoceles. Research is needed, particularly of a cohort or case-control design and including a robust sampling method, to examine the extent of any co-association. Meanwhile, extended renal or retroperitoneal scans should be undertaken when diagnosing all varicoceles, regardless of patient age, until this research is completed.

The Detection of Early Atherosclerosis in Healthy Male Relatives of Men with Peripheral Arterial Disease: a Feasibility Study

Aim: A feasibility study to attempt to determine if conventional ultrasound and multi-gate ultrasound could differentiate between men with peripheral arterial disease (PAD), healthy first-degree male relatives (FDRs) of men with PAD, and age/sex matched controls in identifying early atherosclerosis. Methods: three groups were studied using conventional ultrasound: first, four men with premature PAD (≤65 years); second, four healthy first-degree relatives; third, seven male controls with no known family history or evidence of premature cardiovascular disease. Primary outcome measures were plaque and intima-media thickness of the common carotid artery, flow mediated vasodilatation of the brachial artery, and lower extremity arterial plaque. Multigate Doppler ultrasound blood velocity profile measurements were obtained for three controls, but this series of measurements was discontinued due to technical difficulties. Statistics: mean (standard deviation) and analysis of variance (ANOVA) (p<0·05) Results: Conventional ultrasound demonstrated lower extremity arterial lesions in all four of the patients with PAD. One of their first-degree relatives was found to have a non-significant lesion. No significant carotid artery lesions were found in any of the patients, but males with PAD had significantly greater carotid artery intima-media thickness than a combined group of first-degree relatives and controls (0·75±0·06 mm, versus 0·56±0·07 mm; p≤0·01). The mean (standard deviation) flow mediated vasodilation per cent change of the brachial artery was for males with PAD, 3·49±4·15; relatives, 6·17±2·53; and control subjects, 3·53±6·63. Results from the multigate system were inconclusive. Conclusion: Carotid artery intima-media thickness seemed able to differentiate between patients with PAD and the other two groups. This measurement could be used in future case-control family PAD studies and possibly eventually as a screening tool. Flow mediated dilatation per cent change showed a wide variation in measurements and was not able to differentiate between the three groups. For researchers considering future studies, it is worth noting that recruitment figures for this pilot study were much lower than quoted in previous reports.

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.

Gallbladder perforation: the hole sign

We report a case of gallbladder perforation (GBP) in a patient with right upper quadrant pain and a positive Murphys sign, a previous history of cholelithiasis and co-morbidities. We compare the diagnosis of GBP using the ‘hole-sign’ on ultrasound with the literature for contrast-enhanced ultrasound, computed tomography and magnetic resonance imaging.