EFSUMB Statement on Medical Student Education in Ultrasound [long version].

The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) recommends that ultrasound should be used systematically as an easy accessible and instructive educational tool in the curriculum of modern medical schools. Medical students should acquire theoretical knowledge of the modality and hands-on training should be implemented and adhere to evidence-based principles. In this paper we report EFSUMB policy statements on medical student education in ultrasound that in a short version is already published in Ultraschall in der Medizin 1.

Simulation-Based Abdominal Ultrasound Training - A Systematic Review.

PURPOSE: The aim is to provide a complete overview of the different simulation-based training options for abdominal ultrasound and to explore the evidence of their effect. MATERIALS AND METHODS: This systematic review was performed according to the PRISMA guidelines and Medline, Embase, Web of Science, and the Cochrane Library was searched. Articles were divided into three categories based on study design (randomized controlled trials, before-and-after studies and descriptive studies) and assessed for level of evidence using the Oxford Centre for Evidence Based Medicine (OCEBM) system and for bias using the Cochrane Collaboration risk of bias assessment tool. RESULTS: Seventeen studies were included in the analysis: four randomized controlled trials, eight before-and-after studies with pre- and post-test evaluations, and five descriptive studies. No studies scored the highest level of evidence, and 14 had the lowest level. Bias was high for 11 studies, low for four, and unclear for two. No studies used a test with established evidence of validity or examined the correlation between obtained skills on the simulators and real-life clinical skills. Only one study used blinded assessors. CONCLUSION: The included studies were heterogeneous in the choice of simulator, study design, participants, and outcome measures, and the level of evidence for effect was inadequate. In all studies simulation training was equally or more beneficial than other instructions or no instructions. Study designs had significant built-in bias and confounding issues; therefore, further research should be based on randomized controlled trials using tests with validity evidence and blinded assessors.

EFSUMB statement on medical student education in ultrasound [short version].

The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) recommends that ultrasound should be used systematically as an easy accessible and instructive educational tool in the curriculum of modern medical schools. Medical students should acquire theoretical knowledge of the modality and hands-on training should be implemented and adhere to evidence-based principles. In this paper we summarise EFSUMB policy statements on medical student education in ultrasound.

Ultrasound Elastography in Breast Cancer Diagnosis.

Ultrasound elastography is an established method for characterization of focal lesions in the breast. Different techniques and analyses of the images may be used for the characterization. This article addresses the use of ultrasound elastography in breast cancer diagnosis. In the first part of the article the techniques behind both strain- and shear-wave-elastography are explained and followed by a section on how to obtain adequate elastography images and measurements. In the second part of the article the application of elastography as an adjunct to B-mode ultrasound in clinical practice is described, and the potential diagnostic gains and limitations of elastography are discussed.

Characterization by biopsy or CEUS of liver lesions guided by image fusion between ultrasonography and CT, PET/CT or MRI.

PURPOSE: The aim of this study was to show the number of cases in which the use of fusion-guided ultrasonography (US) provided conclusive diagnosis of lesions in the liver seen on CT or MRI or PET/CT. A lesion is defined as a region that has suffered damage due to injury or disease. MATERIALS AND METHODS: Forty patients of whom 34 had confirmed neoplastic disease, referred to US evaluation or US-guided biopsy of liver lesions seen on CT (n = 35), MRI (n = 2) or PET/CT (n = 3), were prospectively included in the study. We used a LOGIQ prototype system with incorporated software for fusion imaging, and a convex-array 4 MHz transducer (GE Healthcare, Chalfont St. Giles, UK). All patients were initially examined with B-mode US, then by fusion-guided US and for some patients also with CEUS. All patients received follow-up after at least one year. RESULTS: Twenty-six lesions were initially indistinguishable with US. Of these, 9 became visible with fusion-guided US and another 4 became visible with CEUS, which facilitated a final diagnosis in 11 of these 13 patients. The median tumor size for all lesions included in the study was 1.5 cm (interquartile range: 1.0 - 2.4). There was no statistically significant difference in tumor size between the groups. CONCLUSION: We have successfully demonstrated an increase in the characterization of liver lesions by using fusion-guided US compared with conventional B-mode US.

Comparison of two co-registration methods for real-time ultrasonography fused with MRI: a phantom study.

PURPOSE: To test the accuracy of spatial registration of real-time ultrasonography (US) fused with MRI in a phantom. MATERIALS AND METHODS: An US prototype system (LOGIQ, GE Healthcare) with incorporated software for fusion imaging was used to test two methods of co-registration in a phantom: co-registration from specific points, where common reference points identifiable on both MRI and US images were marked, and plane registration, where common planes identifiable on both MRI and US images were marked. In two series we performed co-registration from points and in one series we performed co-registration from planes. The accuracy of the co-registration was measured at 3 measuring points, defined before initiation of the study, and it was calculated as the root mean square deviation (RMSD), which corresponds to the standard deviation. It was measured in millimeters. Two observers each performed 30 co-registrations for each series, totaling 180 co-registrations. The difference between the methods and the observers was calculated using analysis of variance (two-way ANOVA). RESULTS: Co-registration was significantly more accurate when using the measuring points as co-registration points than when using points covering a different area of the phantom (p < 0.0001). The mean calculated RMSD when using the measuring points as co-registration points was 1.3 mm (95 % CI: 1.1 - 1.5 mm), when using points away from the measuring points: 4.0 mm (95 % CI: 3.2 - 4.8 mm), and when using planes for the co-registration: 3.8 mm (95 % CI: 3.2 - 4.4 mm). CONCLUSION: Image fusion involving real-time US has high accuracy and is easy to use in a phantom. Working within the area given by the co-registration points optimizes the accuracy. Image fusion is a promising tool for clinical US, since it provides the potential of benefiting from different imaging modalities in one examination.

In-vivo examples of flow patterns with the fast vector velocity ultrasound method.

PURPOSE: Conventional ultrasound methods for acquiring color flow images of the blood motion are limited by a relatively low frame rate and are restricted to only giving velocity estimates along the ultrasound beam direction. To circumvent these limitations, the Plane Wave Excitation (PWE) method has been proposed. MATERIAL AND METHODS: The PWE method can estimate the 2D vector velocity of the blood with a high frame rate. Vector velocity estimates are acquired by using the following approach: The ultrasound is not focused during the ultrasound transmission, and a full speckle image of the blood can be acquired for each pulse emission. The pulse is a 13 bit Barker code transmitted simultaneously from each transducer element. The 2D vector velocity of the blood is found using 2D speckle tracking between segments in consecutive speckle images. Implemented on the experimental scanner RASMUS and using a 100 CPU linux cluster for post processing, PWE can achieve a frame of 100 Hz where one vector velocity sequence of approximately 3 sec, takes 10 h to store and 48 h to process. In this paper a case study is presented of in-vivo vector velocity estimates in different complex vessel geometries. RESULTS: The flow patterns of six bifurcations and two veins were investigated. It was shown: 1. that a stable vortex in the carotid bulb was present opposed to other examined bifurcations, 2. that retrograde flow was present in the superficial branch of the femoral artery during diastole, 3. that retrograde flow was present in the subclavian artery and antegrade in the common carotid artery during diastole, 4. that vortices were formed in the sinus pockets behind the venous valves in both antegrade and retrograde flow, and 5. that secondary flow was present in various vessels. CONCLUSION: Using a fast vector velocity ultrasound method, in-vivo scans have been recorded where complex flow patterns were visualized in greater detail than previously visualized by conventional color flow imaging techniques.

Sentinel node detection in melanomas using contrast-enhanced ultrasound.

BACKGROUND: Sentinel node (SN) biopsy has proven to be a useful clinical method based on the combination of radionuclide tracer principles and the dye technique. Contrast-enhanced ultrasound (CEUS) has been used successfully for detection of SN in animals, but the use of CEUS has not been reported in humans. PURPOSE: To investigate the possible use of CEUS in detecting SN in patients with malignant melanomas (MM), and to improve the method by using different concentrations of contrast agent and various positions of the extremity. MATERIAL AND METHODS: Ten patients with MM on an extremity and one healthy volunteer were included. One milliliter of a contrast agent (Sonovue; Bracco, Milan, Italy) was injected subcutaneously on both sides of the scar from the excised tumor. Contrast-enhanced lymph channels and lymph nodes (LNs) were searched for using low-mechanical-index CEUS and by stimulated acoustic emission. Afterward, lymphoscintigraphy was performed and the patient operated. During surgery, the SNs were located via scintigraphic findings, gamma-probe signals, and blue-dye visualization of lymph channels and LNs. Before the human study, a study of 10 mice was performed to exclude possible tissue damage, as the contrast agent was not registered for subcutaneous administration. RESULTS: In one patient, two contrast-enhanced inguinal LNs were visualized by CEUS, corresponding to two inguinal SNs found by scintigraphic imaging. No contrast-enhanced lymph channels or LNs were visualized in any other patients or in the volunteer. No tissue damage was observed in the 10 mice. CONCLUSION: This study does not support the use of CEUS for detection of SNs in humans. However, the application of CEUS for the investigation of SNs is still not fully explored in humans, and an alternative setup and/or contrast agent might provide better results.

Evaluation of contrast-enhanced ultrasound of the pancreas combined with concurrent hormone stimulation.

PURPOSE: To evaluate the potential of combined administration of the gastrointestinal hormones secretin (Secrelux) and c-terminal cholecystokinin (CCK-8 s) together with contrast-enhanced ultrasound (CE-US) to generate an extended contrast enhancement of healthy pancreatic tissue. MATERIALS AND METHODS: 14 anaesthetised pigs weighing 30-35 kg were studied. After laparotomy, the pancreas was located and a B-mode examination followed by a CE-US examination of the gland was made using SonoVue 1.5 ml. After an injection of Secrelux 1 U/kg and CCK-8 s 100 pmol/kg, a second CE-US examination was conducted. The hormones and the contrast agent were administered through a catheter in the superior vena cava. The sonographic images were stored for later evaluation. RESULTS: The study showed that CE-US increased the echogenicity of the pancreas by an average of 15.6 decibel (dB) (confidence intervals [CI]: 13.72, 17.42) p < 0.0001, an increase of 24%. The administration of Secrelux and CCK-8 s in combination with CE-US further increased the echogenicity of the pancreas by an average of 3% (CI: 0.36, 5.36) p = 0.028. A new sequence of hormones and CE-US 20 min after the previous injection did not induce further enhancement. The area under the curve (AUC) was significantly larger using both hormones and CE-US compared with CE-US alone by an average of 66 dBx sec (CI: 28,103) p = 0.002. CONCLUSION: It is possible to generate an extended contrast enhancement of healthy pancreatic tissue using CE-US combined with the administration of the gastrointestinal hormones secretin (Secrelux) and c-terminal cholecystokinin (CCK-8 s). Our results may improve the ability to discriminate between healthy pancreatic tissue and areas with a changed blood flow due to either neoplasm or other pathological lesions.

Reproducibility of ultrasound and magnetic resonance imaging measurements of tendon size.

PURPOSE: To investigate the intra- and inter-tester reproducibility of measurements of the Achilles tendon, tibialis anterior tendon, and the tibialis posterior tendon in football players using ultrasound (US) and magnetic resonance imaging (MRI). MATERIAL AND METHODS: Eleven asymptomatic football players were examined. Using a standardized US scanning protocol, the tendons were examined by two observers with US for thickness, width, and cross-sectional area. One observer conducted the procedure twice. The subjects also underwent an MRI examination, and the assessment of tendon size was conducted twice by two observers. RESULTS: The best reproducibility judged by coefficient of variation (CV) and 95% confidence interval was determined for the Achilles tendon on both US and MRI. The variability of US on measurements on the tibialis anterior and tibialis posterior tendons was less than that when using MRI. In 12 out of 18 measurements, there were systematic differences between observers as judged by one-sided F-test. CONCLUSION: The reproducibility of the three tendons was limited. Precaution should be taken when looking for minor quantitative changes, i.e., training-induced hypertrophy, and when doing so, the Achilles tendon should be used.