Liver and Spleen Stiffness Measurements by Point Shear Wave Elastography via Acoustic Radiation Force Impulse: Intraobserver and Interobserver Variability and Predictors of Variability in a US PopulationJournal of Ultrasound in Medicine November 2016 35:2373-2380;Published Online First September 23, 2016, doi:10.7863/ultra.15.10056
Sonographic Evaluation for Endometrial Polyps: The Interrupted Mucosa SignJournal of Ultrasound in Medicine November 2016 35:2381-2387;Published Online First September 14, 2016, doi:10.7863/ultra.15.09007
Elastography Improves the Diagnostic Accuracy of Sonography in Differentiating Endometrial Polyps and Submucosal FibroidsJournal of Ultrasound in Medicine November 2016 35:2389-2395;Published Online First September 14, 2016, doi:10.7863/ultra.15.12017
Does Shear Wave Elastography Provide Additional Value in the Evaluation of Thyroid Nodules That Are Suspicious for Malignancy?Journal of Ultrasound in Medicine November 2016 35:2397-2404;Published Online First October 25, 2016, doi:10.7863/ultra.15.09009
Completed Sonographic Anatomic Surveys: The Exception Rather Than the RuleJournal of Ultrasound in Medicine November 2016 35:2441-2447;Published Online First September 23, 2016, doi:10.7863/ultra.15.12001
Use of Point-of-Care Ultrasound in the Emergency Department:Insights From the 2012 Medicare National Payment Data SetJournal of Ultrasound in Medicine November 2016 35:2467-2474;Published Online First October 3, 2016, doi:10.7863/ultra.16.01041
Clinicopathologic Factors and Thyroid Nodule Sonographic Features for Predicting Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma: A Retrospective Study of 1204 PatientsJournal of Ultrasound in Medicine November 2016 35:2475-2481;Published Online First October 25, 2016, doi:10.7863/ultra.15.10012
Basic Abdominal Point-of-Care Ultrasound Training in the Undergraduate: Students as MentorsJournal of Ultrasound in Medicine November 2016 35:2483-2489;Published Online First October 13, 2016, doi:10.7863/ultra.15.11068
Value of Ultrasound Elastography in the Differential Diagnosis of Cervical Lymph Nodes: A Comparative Study With B-mode and Color Doppler SonographyJournal of Ultrasound in Medicine November 2016 35:2491-2499;doi:10.7863/ultra.15.09019
Liver and Spleen Stiffness Measurements by Point Shear Wave Elastography via Acoustic Radiation Force Impulse
Intraobserver and Interobserver Variability and Predictors of Variability in a US Population
Objectives—Measurements of liver stiffness and spleen stiffness are useful noninvasive ways to assess fibrosis and portal hypertension in patients with chronic liver disease. One method for assessing stiffness is by point shear wave elastography via acoustic radiation force impulse imaging (ARFI). Its advantage is that sites where stiffness is measured are visualized sonographically. However, its reliability has not been well established, and all studies done to date evaluating the use of ARFI in chronic liver disease have been performed outside the United States. We aimed to characterize the intraobserver and interobserver variability of ARFI-measured liver and spleen stiffness.
Methods—Two hepatologists evaluated unselected hepatology outpatients with ARFI. Exclusions were hepatocellular carcinoma, ascites, a surgical shunt or transjugular intrahepatic portosystemic shunt, portal thrombosis, and cholestatic disease. Each operator obtained 20 measurements from the right liver lobe and spleen. Intraclass correlation coefficients (ICC) were calculated.
Results—A total of 177 patients were included: median age, 61 years; 85% male; and 43% obese. Intraobserver ICCs were the same for both observers for liver stiffness (0.89; 95% confidence interval [CI], 0.85–0.92) and spleen stiffness (0.72; 95% CI, 0.61–0.80). Interobserver agreement was excellent for liver stiffness (ICC, 0.85; 95% CI, 0.76–0.90) but not as good for spleen stiffness (ICC, 0.73; 95% CI, 0.60–0.83). A body mass index of 30 kg/m2 or greater, waist circumference of greater than 105 cm, and skin-to-capsule distance of 2 cm or greater negatively affected the ICC for liver stiffness; small spleen size negatively affected the ICC for spleen stiffness.
Conclusions—To our knowledge, this article is the first report of ARFI findings in a US population with chronic liver disease. Liver stiffness reproducibility was excellent, particularly in nonobese patients. Spleen stiffness reproducibility was excellent in those with larger spleens and therefore may be most useful in patients with cirrhosis and portal hypertension.
Objectives—To evaluate the interrupted mucosa sign for identification of endometrial polyps, using pathologic confirmation as the reference standard, compared to other accepted sonographic findings.
Methods—We reviewed 195 patients referred for pelvic sonographic evaluations for suspected endometrial polyps in this retrospective Institutional Review Board–approved study. Of these, 82 had tissue sampling of the endometrium and constituted the final study group. Patient data, including age, menopausal status, last menstrual period, and final pathologic diagnosis, were recorded. Sonograms were reviewed by 2 blinded board-certified radiologists for endometrial features, including thickness, echogenicity, vascularity, presence of a mass, and the interrupted mucosa sign. Descriptive statistics and multivariate logistic regression analysis were performed.
Results—The mean age of the patients was 44.99 (SD, 9.88) years, 79.1% of whom were premenopausal. Pathologic diagnosis confirmed polyps in 58 (70.73%). A single feeding vessel was visualized in 36 patients with polyps (62.07%), whereas the interrupted mucosa sign was visualized in 34 (58.62%). The presence of a feeding vessel, the interrupted mucosa sign, or both detected 48 (82.76%) of the polyps. In the multivariate analysis, only the interrupted mucosa sign was a statistically significant predictor of pathologic diagnosis of a polyp (P= .035), with an odds ratio of 3.83 (95% confidence interval, 1.10–13.29). Other sonographic findings were not independent predictors of a polyp: mass (P = .35), single feeding vessel (P= .31), endometrial thickness (P = .88), and endometrial echogenicity (P = .45). The sensitivity, specificity, and positive predictive value of the interrupted mucosa sign were 59%, 75%, and 85%, respectively.
Conclusions—The interrupted mucosa sign is a promising sonographic sign for identification of endometrial polyps, with greater predictive power than previously described signs. It has the potential to improve the diagnostic performance of sonography, especially when used in combination with other described signs.
Elastography Improves the Diagnostic Accuracy of Sonography in Differentiating Endometrial Polyps and Submucosal Fibroids
Objectives—To assess whether strain elastography may be used to visualize the different stiffness of endometrial polyps and submucosal fibroids.
Methods—We conducted a prospective monocentric single-operator study on diagnostic accuracy. Patients who qualified for hysteroscopy because of suspected endometrial polyps and submucosal fibroids were included. Before the procedure, all patients underwent routine sonographic and power Doppler examinations. Additionally, the stiffness of intrauterine lesions was assessed by strain elastography. The enhancement was adjusted to visualize hard myometrium and soft endometrium around the intrauterine lesion. Due to their histologic structure, we assumed that on strain elastography, endometrial polyps should appear as soft lesions, whereas submucosal fibroids should appear as hard lesions. Sonographic, power Doppler, and elastographic findings were verified by pathologic examinations after hysteroscopies. The diagnostic accuracy of sonography, power Doppler imaging, and strain elastography was compared by the McNemar test.
Results—Forty-seven patients were included and underwent hysteroscopy. In 29 cases, endometrial polyps were found, and in 18, submucosal fibroids were found. The diagnostic accuracy rates for B-mode sonography, power Doppler imaging, and strain elastography in distinguishing endometrial polyps and submucosal fibroids were 70.2%, 65.9%, and 89.4%, respectively. The proportion of correct findings was significantly higher for strain elastography than for B-mode sonography (P = .0265) and power Doppler imaging (P = .0153).
Conclusions—Strain elastography complements sonography in differentiating intrauterine lesions. Strain elastography may be used to visualize the different stiffness of endometrial polyps and submucosal fibroids.
Does Shear Wave Elastography Provide Additional Value in the Evaluation of Thyroid Nodules That Are Suspicious for Malignancy?
Objectives—We aimed to determine whether the integration of shear wave elastography (SWE) with conventional ultrasonography (US) improves diagnostic performance for suspicious thyroid lesions.
Methods—For 215 thyroid lesions in 185 patients classified as Thyroid Imaging Reporting and Data System category 4 or 5 according to the findings of conventional US, SWE elasticity indices were automatically calculated. A receiver operating characteristic curve analysis was used to determine the threshold. Thyroid Imaging Reporting and Data System categories were upgraded for high-stiffness nodules and unchanged for low- and normal-stiffness nodules. The diagnostic performances were assessed and compared with histologic findings. Intraobserver and interobserver variability of SWE was assessed.
Results—Elasticity indices were significantly higher in malignant versus benign nodules (P≤ .001). The minimum elasticity index (cutoff, 40.7 kPa) of the stiffest part combined with conventional US showed the highest area under the curve (0.774; 95% confidence interval, 0.682–0.866) but was not superior to conventional US (0.791; 95% confidence interval, 0.706–0.876; P = .48). Combined with the standard deviation of the elasticity index for the whole lesion (cutoff, 6.8 kPa), US yielded the highest sensitivity (95.5%; P < .001) and lowest specificity (42.1%; P < .001). Sensitivity increased and specificity decreased by adding any other SWE elasticity index. The intraobserver and interobserver reliability of SWE was fair to excellent according to the interclass correlation coefficients, with correlation coefficients of 0.765 to 0.846 (all P < .001).
Conclusions—The SWE elasticity indices of malignant thyroid nodules were significantly high. Adding SWE to conventional US did not improve diagnostic performance.
Sonographic Differentiation Between Angiolipomas and Superficial Lipomas
Objectives—The purpose of this study was to compare the sonographic findings of angio lipomas with those of superficial lipomas.
Methods—Preoperative sonograms of 26 angiolipomas from 18 patients and 47 superficial lipomas from 43 patients that were confirmed by biopsy were reviewed retrospectively. The echo texture, echogenicity, internal echogenic stranding, vascularity, visualization of lateral and superficial-deep tumor capsules, shape, and tumor length, width, and length-to-width ratio were evaluated and compared between angiolipomas and superficial lipomas.
Results—Angiolipomas frequently appeared as heterogeneous (19 of 26 [73.1%]), hyperechoic (23 of 26 [88.5%]), and ovoid (17 of 26 [65.4%]) masses with lesser visualized lateral tumor capsules (6 of 26 [23.1%]), whereas superficial lipomas appeared as homogeneous (36 of 47 [76.6%]), isoechoic (35 of 47 [74.5%]), and spindle-shaped (23 of 47 [48.9%]) masses with well-visualized lateral capsules (33 of 47 [70.2%]), and the differences were statistically significant (P < .001). Vascularity was seen in 4 angiolipomas (16.7%) and in no superficial lipomas (0%). The mean length and width ± SD of angiolipomas (2.2 ± 1.02 and 0.6 ± 0.27 cm, respectively) were smaller than those of superficial lipomas (4.2 ± 1.52 and 1.1 ± 0.51 cm), with statistical significance (P< .001). The other sonographic findings did not reveal statistically significant differences between the tumor types.
Conclusions—Sonography might help differentiate angiolipomas from superficial lipomas.
Objectives—To determine how often fetal organ systems are imaged completely and whether this rate varies by hospital.
Methods—All initial sonographic anatomic examinations between 16 and 24 weeks from 3 hospitals (perinatal designation levels I–III) from January 2012 through December 2013 were identified in their obstetric and gynecologic anatomic survey report databases, focusing on 36 anatomic fields. Structures were grouped into regions: brain, face, spine, heart, abdomen, and extremities. Rates of complete visualization of each structure, structure grouping, and the total were calculated and compared by χ2 testing.
Results—From 7211 examinations (2578 from level I, 986 from level II, and 3647 from level III), the completion rate was 16.8% (I, 20.6%; II, 20.0%; and III, 13.2%; P < .00001). Brain and extremity imaging was complete 85% of the time or more but spine only 62.4% (sacrum consistently lowest). Completeness rates varied significantly (P< .00001) for the face (28.1%–64.4%, due to low rates of clearing lips at level III, and level I not clearing profiles), heart (37.3%–56.1%, level I < II < III), and abdomen (65.2%–85.7%, due to lower rates of clearing kidneys at level I). Completion of both the heart and spine was 32.0% (I, 23.0%; II, 25.4%; and III, 40.2%; P < .00001).
Conclusions—With a comprehensive reporting system, completion rates for full anatomic sonograms are low. Facial, cardiac, and spinal structures are least complete, and follow-up examinations often remain incomplete. Completion benchmarks would be helpful because “incomplete” studies lead to repeated examinations that increase health care costs.
Use of Point-of-Care Ultrasound in the Emergency Department
Insights From the 2012 Medicare National Payment Data Set
Objectives—Point-of-care ultrasound is a valuable tool with potential to expedite diagnoses and improve patient outcomes in the emergency department. However, little is known about national patterns of adoption. This study examined nationwide point-of-care ultrasound reimbursement among emergency medicine (EM) practitioners and examined regional and practitioner level variations.
Methods—Data from the 2012 Center for Medicare and Medicaid Services Fee-for-Service Provider Utilization and Payment Data include all practitioners who received more than 10 Medicare Part B fee-for-service reimbursements for any Healthcare Common Procedure Coding System code in 2012. Odds ratios (ORs) and descriptive statistics were calculated to assess relationships between ultrasound reimbursement and practice location, nearby presence of an EM residency, and time elapsed since practitioner graduation.
Results—Of 52,928 unique EM practitioners, 391 (0.7%) received limited ultrasound reimbursements for a total of 16,389 scans in 2012. Urban counties had an OR of 5.4 (95% confidence interval, 3.8–7.8) for receiving point-of-care ultrasound reimbursements compared to rural counties. Counties with an EM residency had an OR of 84.7 (95% confidence interval, 42.6–178.8) for reimbursement compared to counties without. The OR for receiving reimbursement was independent of medical school graduation year (P = .83); however, recent graduates performed more scans (P = .02).
Conclusions—A small minority of EM practitioners received reimbursements for point-of-care ultrasound from Medicare beneficiaries. These practitioners were more likely to reside in urban and academic settings. Future efforts should assess the degree to which our findings reflect either low point-of-care ultrasound use or low rates of billing for ultrasound examinations that are performed.
Clinicopathologic Factors and Thyroid Nodule Sonographic Features for Predicting Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma
A Retrospective Study of 1204 Patients
Objectives—Preoperative prediction of lymph node metastasis is of clinical importance for the surgical treatment of thyroid tumor. The purpose of this study was to evaluate clinicopathologic factors and thyroid nodule sonographic features predictive of central lymph node metastasis in papillary thyroid microcarcinoma.
Methods—Clinicopathologic factors and thyroid nodule sonographic features of 1204 patients with papillary thyroid microcarcinoma were retrospectively reviewed from January 2014 to June 2015. Central lymph node dissection was performed on each patient. Univariate and multivariate analyses were performed to analyze the clinicopathologic factors and thyroid nodule sonographic features associated with central lymph node metastasis in papillary thyroid microcarcinoma. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the relevance of all potential predictive factors.
Results—Central lymph node metastasis was detected in 395 of the 1204 patients (32.81%). By univariate and multivariate analyses, younger age (≤43 years), male sex, larger tumor size (≥7 mm), multifocal papillary thyroid microcarcinoma and microcalcification were independently associated with central lymph node metastasis in papillary thyroid microcarcinoma (P < .05). The ORs were 1.920 (95% CI, 1.476–2.499), 1.665 (95% CI, 1.234–2.247), 1.534 (95% CI, 1.177–2.000), 2.120 (95% CI, 1.563–2.877), and 4.109 (95% CI, 3.118–5.414), respectively.
Conclusions—Central lymph node metastasis is highly prevalent in papillary thyroid microcarcinoma. Younger age (≤43 years), male sex, larger tumor size (≥7 mm), multifocal papillary thyroid microcarcinoma, and microcalcification were independent predictors of central lymph node metastasis. Surgeons and radiologists need to pay more attention to patients with papillary thyroid microcarcinoma who have these risk predictors.
Basic Abdominal Point-of-Care Ultrasound Training in the Undergraduate
Students as Mentors
Objectives—To analyze the ability of medical students to be integrated in the teaching of basic abdominal ultrasound using a peer-mentoring design.
Methods—Thirty medical students previously trained in basic abdominal ultrasound (mentors) had to teach all fourth-year students (n = 136) from a single academic year the same training they had received. There were 3 stages to the ultrasound teaching: theoretical (online course); basic training (3 practical sessions in which students were guaranteed to have had a minimum of 15 hours of practical experience with ultrasound and performed at least 20 basic abdominal ultrasound studies); and evaluation (objective structured clinical examination in which students had to obtain the basic abdominal views and to identify 17 structures).
Results—The mean grade ± SD obtained was 8.71 ± 1.53 of a possible 10 points. Only 2 students (1.56%) obtained a grade lower than 5, and 14 students (10.86%) obtained a grade lower than 7. A total of 33 students (25.5%) achieved the maximum grade. The structures most easily identified were the liver, the right kidney, and the urinary bladder, with 97.7% of correct answers. Students obtained the poorest results when trying to identify the left and right cardiac cavities (subxiphoid view), with only 53.5% and 55.8% of correct answers, respectively.
Conclusions—Teaching based on peer mentoring achieved an adequate level of training in basic abdominal ultrasound. The students acquired these skills in a relatively short training period. These results suggest that peer mentoring can facilitate the large-scale implementation of ultrasound teaching in undergraduate students.
Value of Ultrasound Elastography in the Differential Diagnosis of Cervical Lymph Nodes
A Comparative Study With B-mode and Color Doppler Sonography
Objectives—The purpose of this study was to determine the usefulness of ultrasound elastography in the evaluation of enlarged cervical lymph nodes in comparison with B-mode and color Doppler sonography.
Methods—A total of 220 lymph nodes in 168 consecutive patients who were referred for sonography of the neck were included in this study. B-mode sonograms were evaluated according to short-axis diameter, long-to-short-axis ratio, hilum, echogenicity, and microcalcification. For color Doppler sonography, 5 different patterns were defined according to vascularity. Elastographic patterns of the lesions were categorized to 5 main types. The mean strain index values were calculated for all lymph nodes. Histopathologic findings, clinical and laboratory data, and imaging findings were used as reference standards for the diagnosis of benign and malignant lymph nodes.
Results—Of the 220 lymph nodes, 69.5% were diagnosed as benign, and 30.5% were diagnosed as malignant. The sensitivity, specificity, and accuracy of B-mode sonography were 97.0%, 31.4%, and 51.3%, respectively; the values were 76.1%, 82.4%, and 80.5% for color Doppler sonography and 82.1%, 56.2%, and 64.1% for elastography. The strain index cutoff value for the differentiation of benign and malignant lymph nodes was accepted as 1.7. The sensitivity, specificity, and accuracy of the strain index were 71.6%, 76.5%, and 75.0%.
Conclusions—Ultrasound elastography adds no additional value to combined B-mode and color Doppler sonography for differentiation of benign and malignant cervical lymph nodes.