Development of a reliable simulation-based test for diagnostic abdominal ultrasound with a pass/fail standard usable for mastery learning.

BACKGROUND: This study aimed to develop a test with validity evidence for abdominal diagnostic ultrasound with a pass/fail-standard to facilitate mastery learning. METHOD: The simulator had 150 real-life patient abdominal scans of which 15 cases with 44 findings were selected, representing level 1 from The European Federation of Societies for Ultrasound in Medicine and Biology. Four groups of experience levels were constructed: Novices (medical students), trainees (first-year radiology residents), intermediates (third- to fourth-year radiology residents) and advanced (physicians with ultrasound fellowship). Participants were tested in a standardized setup and scored by two blinded reviewers prior to an item analysis. RESULTS: The item analysis excluded 14 diagnoses. Both internal consistency (Cronbach's alpha 0.96) and inter-rater reliability (0.99) were good and there were statistically significant differences (p < 0.001) between all four groups, except the intermediate and advanced groups (p = 1.0). There was a statistically significant correlation between experience and test scores (Pearson's r = 0.82, p < 0.001). The pass/fail-standard failed all novices (no false positives) and passed all advanced (no false negatives). All intermediate participants and six out of 14 trainees passed. CONCLUSION: We developed a test for diagnostic abdominal ultrasound with solid validity evidence and a pass/fail-standard without any false-positive or false-negative scores. KEY POINTS: • Ultrasound training can benefit from competency-based education based on reliable tests. • This simulation-based test can differentiate between competency levels of ultrasound examiners. • This test is suitable for competency-based education, e.g. mastery learning. • We provide a pass/fail standard without false-negative or false-positive scores.

Use of contrast-enhanced ultrasound imaging to detect the first draining lymph node (FDLN) in a swine model: correlation of imaging findings with the distance from the injection site to the FDLN.

OBJECTIVE: The purpose of this study was to investigate the use of contrast-enhanced ultrasound imaging (CEUS) to detect the first draining lymph node (FDLN) in a swine model and to determine whether the distance from the contrast agent injection site to the FDLN has any affect on the ability to detect contrast-enhanced FDLNs. METHODS: Thirteen swine (25-32 kg) were anesthetized during examinations and euthanized afterward. In every swine, 1 mL of a sulfur hexafluoride microbubble ultrasound contrast agent was bilaterally injected subcutaneously below a mammilla. The examined distances varied from 6 to 36 cm. The contrast-enhanced lymphatic channels were visualized with low-mechanical index CEUS and mapped from the injection site to the FDLN. After CEUS was performed, blue dye was injected in the same locations as the contrast agent, and dye-guided surgery was used to localize the FDLNs. To ensure the lymph node detected with the blue dye technique was the same found with CEUS, it was scanned again to confirm contrast enhancement. RESULTS: After 26 injections, 22 inguinal FDLNs were detected with CEUS and the blue dye technique. After 4 injections in 2 swine, contrast-filled lymphatic channels were identified with a course running toward the neck. In all cases but 1, the FDLNs received the contrast agent within 5 minutes. CONCLUSIONS: In this swine model, it was possible to use CEUS to locate the FDLNs. In these preliminary experiments, the distances from the contrast agent injection site to the FDLN did not affect the ability to detect the contrast-enhanced FDLNs.

Targeted ultrasound and fine-needle aspiration cytology for sentinel node diagnostics in early-stage melanoma: a validation study.

Ultrasound-guided fine-needle aspiration cytology (US-FNAC) is used to evaluate the involvement of lymph nodes in various malignant diseases. Its value in detecting sentinel lymph node (SN) metastasis preoperatively in melanoma patients is controversial and is the subject of this study. In this prospective validation study, 91 consecutive patients with melanoma clinical stage I (n=64) and II (n=27) were examined with US-FNAC before SN biopsy from 2012 to 2014 at a tertiary center. All patients underwent lymphoscintigraphy before the US-FNAC. Lymph nodes that showed any of the Berlin morphologic criteria on ultrasonography were examined using FNAC. The median Breslow thickness of the melanomas was 1.22 mm (range: 0.47-11.5 mm). Twenty-two percent of the patients had metastases in their SNs, 90% of which were smaller than 2 mm in largest diameter. The percentages of metastases with a size more than 1 mm were 50 and 29%, respectively, in the true-positive and false-negative US groups. The sensitivity, specificity, positive predictive value, and negative predictive value for overall US examination were 30, 81, 24, and 83%, respectively. None of the FNACs contained conclusive malignant cells. The specificity of the FNAC was 76%. Our results show that US-FNAC was not a useful diagnostic tool in our setting as it did not add significantly to the staging and management of patients with mainly thin cutaneous melanomas, perhaps because of the often small size of the SN metastases. It may be useful in the early diagnosis of lymph node metastases in a subgroup of melanoma patients with larger metastases.

Axillary sentinel node identification in breast cancer patients: degree of radioactivity present at biopsy is critical.

BACKGROUND: The radioactivity present in the patient (Act(rem) ) at sentinel node (SN) biopsy will depend on injected activity amount as well as on the time interval from tracer injection to biopsy, which both show great variations in the literature. The purpose of this study was to analyse the influence of varying Act(rem) levels on the outcome of axillary SN biopsy in patients with breast cancer (BC). MATERIAL AND METHODS: Eight hundred and fifty-eight patients with BC were consecutively referred to SN biopsy, 21% for a same-day and 79% of the patients for a 2-day procedure. Four hundred and nineteen patients underwent scintigraphy and 439 did not. For same-day procedures, 50 MBq (99m) Tc-nanocolloid (Nanocoll(®) ) was injected, and for 2-day procedures 110 MBq. For the analysis of SN biopsy outcome, the patients were divided into three Act(rem) groups: <10 (56% of the patients), 10-20 (23%), and >20 MBq (21%). During surgery, SNs were located using a hand-held gamma probe supported by image information when available and blue dye injection. Pathology included haematoxylin-eosin staining followed by immunohistochemistry. RESULTS: The number of SNs removed (mean value 1·87 versus 2·14, P = 0·0003) and the probability of finding a malignant SN (P = 0·034) were lower in the <10 MBq group of patients compared with higher Act(rem) >20 MBq. Of the 25 patients with SN non-detection, 20 patients had an Act(rem) <10 MBq. Imaging had no significant influence on the number of patients with a malignant SN (P = 0·48). CONCLUSION: Act(rem) above 10 MBq for nanocolloid tracer appears important for appropriate identification of SNs in patients with BC.