Shin Ho Kook

Practice guideline for the performance of breast ultrasound elastography

Ultrasound (US) elastography is a valuable imaging technique for tissue characterization. Two main types of elastography, strain and shear-wave, are commonly used to image breast tissue. The use of elastography is expected to increase, particularly with the increased use of US for breast screening. Recently, the US elastographic features of breast masses have been incorporated into the 2nd edition of the Breast Imaging Reporting and Data System (BI-RADS) US lexicon as associated findings. This review suggests practical guidelines for breast US elastography in consensus with the Korean Breast Elastography Study Group, which was formed in August 2013 to perform a multicenter prospective study on the use of elastography for US breast screening. This article is focused on the role of elastography in combination with B-mode US for the evaluation of breast masses. Practical tips for adequate data acquisition and the interpretation of elastography results are also presented.

Validation of intra- and interobserver reproducibility of shearwave elastography: Phantom study

PURPOSE To assess intra- and interobserver reproducibility of quantitative ultrasound (US) elastography for breast masses using shearwave elastography (SWE). MATERIALS AND METHODS The US elastography phantom was used. This training phantom contained 12 masses with dimensions from 6 to 11mm and varying B-mode (hypo- iso- and hyperechoic) characteristics and viscoelastic properties varying from about 50 to 250kPa. Four attending radiologists participated as operators and used Supersonic Imaging 15-4 MHz array to acquire images. In each session, B-mode US features were assessed once and US elastography values were assessed twice in a consecutive and distinct manner. A total of three identical sessions of data acquisition were performed at 2-week intervals. For categorical variables such as BI-RADS features of mass on B-mode image and qualitative SWE features, kappa (k) values were calculated by the generalized linear mixed model. For continuous variables, kPa, and ratio, intraclass correlation coefficients (ICCs) were calculated. RESULTS Interobserver agreement for SWE image similarity was moderate (k=0.57). With respect to quantitative SWE values, intraobserver ICCs were 0.65, 0.77, 0.92, and 0.91 for maximum elasticity; 0.70, 0.83, 0.94, and 0.94 for mean elasticity; and 0.67, 0.83, 0.92, and 0.92 for elasticity ratio for operators 1, 2, 3, and 4, respectively. Interobserver reproducibility showed good agreement with ICC values of 0.77 for maximum elasticity, 0.82 for mean elasticity, and 0.79 for elasticity ratio. CONCLUSION Quantitative US elastography for breast masses was highly reproducible with good agreement across operators. With respect to intraobserver reproducibility, ICC values varied but three out of four operators showed good agreement.

Ultrasound and Clinicopathological Characteristics of Triple Receptor-Negative Breast Cancers

Purpose Triple receptor-negative (TRN) breast cancer is associated with high risk of recurrence and poor prognosis. The present study assessed the clinicopathologic characteristics and ultrasound (US) features of TRN breast cancers. Methods Pathological and biological data were reviewed for 558 breast cancer patients treated at Kangbuk Samsung Hospital, between January 2003 and December 2009. The patients were separated into TRN breast cancer and non-TRN breast cancer groups, based on the results of immunohistochemical prognostic panels. Clinical and pathologic features were compared for the two groups. US features, including shape, orientation, margins, boundaries, echo patterns, posterior acoustic features, surrounding tissues, and microcalcifications, were determined for 41 TRN patients and 189 non-TRN controls (ER+/PR+/HER2-). Results Of 558 cases, 58 (10.4%) had the TRN phenotype. Four hundred and thirty-four cases (77.8%) were invasive ductal carcinomas. TRN cancer was significantly associated with specific characteristics of tumor size, nuclear grade, histologic grade, venous invasion, and lymphatic invasion. With respect to US features, TRN cancers were more likely to have an oval shape, a circumscribed margin, and marked hypoechogenicity. Conclusion Tumor characteristics were different between TRN and non-TRN breast cancers, although US cannot differentiate the subtype of breast cancers TRN cancer tend to show somewhat different US morphology.

Value of adding sonoelastography to conventional ultrasound in patients with congenital muscular torticollis

BackgroundSonoelastography has been utilized to evaluate various myopathies. However, the benefits of adding sonoelastography to conventional ultrasound (US) in patients with congenital muscular torticollis are unclear.ObjectiveTo evaluate the value of adding sonoelastography to conventional US in patients with congenital muscular torticollis.Materials and methodsThis study included 27 infants clinically diagnosed with congenital muscular torticollis and 17 healthy infants who underwent conventional US and sonoelastography. The echogenicity of the sternocleidomastoid muscle was assessed as isoechoic, heterogeneous, hyperechoic or hypoechoic compared with normal muscle. The thickness of the involved and contralateral sternocleidomastoid muscles was measured. Elastographic findings were scored from 1 (soft) to 3 (hard) by two independent radiologists.ResultsThe sternocleidomastoid muscle thickness, difference and ratio between involved and normal sternocleidomastoid muscle thickness, and elastographic score differed significantly between the patient and control groups. Of the 27 patients, 11 had isoechoic, 5 had heterogeneous and 11 had hyperechoic muscles. Congenital muscular torticollis patients with isoechoic muscle showed significantly higher elastographic scores than the control group, but there were no other significant differences by conventional US.ConclusionsAdding sonoelastography to conventional US is helpful for the diagnosis of congenital muscular torticollis, especially in patients with isoechoic sternocleidomastoid muscle.

Evaluation of cervical lymph node metastasis in thyroid cancer patients using real-time CT-navigated ultrasonography: preliminary study.

Purpose: To evaluate the diagnostic accuracy of real-time neck computed tomography (CT)-guided ultrasonography (US) in detecting cervical neck lymph node metastasis (LNM) in patients with papillary thyroid cancer (PTC). Methods: We retrospectively reviewed data from 176 patients (mean age, 43 years; range, 23 to 74 years) with surgically confirmed PTC who underwent preoperative US, neck CT, and neck CTguided US. We then compared the sensitivities and diagnostic accuracies of each of the three above modalities in detecting cervical LNM. Results: Preoperative US showed 17.3% sensitivity and 58.5% diagnostic accuracy in detecting central LNM compared with 64.3% sensitivity and 89.2% diagnostic accuracy in detecting lateral neck LNM. Neck CT showed 23.5% sensitivity and 55.7% diagnostic accuracy in detecting central LNM and 71.4% sensitivity with 90.9% diagnostic accuracy in detecting lateral neck LNM. CT-guided US exhibited 37.0% sensitivity and 63.1% diagnostic accuracy in detecting central LNM compared with 92.9% sensitivity and 96.0% diagnostic accuracy in detecting lateral LNM. CT-guided US showed higher diagnostic accuracy with superior sensitivity in detecting central and lateral LNM than did US (P<0.001, P=0.011) and CT (P=0.026, P=0.063). Conclusion: Neck CT-guided US is a more accurate technique with higher sensitivity for detecting cervical LNM than either US or CT alone. Therefore, our data indicate that neck CT-guided US is an especially useful technique in preoperative examinations.

Ultrasonography-guided surgical clip placement for tumor localization in patients undergoing neoadjuvant chemotherapy for breast cancer.

Purpose We investigated the feasibility of using surgical clips as markers for tumor localization and their effect on the imaging evaluation of treatment responses after neoadjuvant chemotherapy (NAC). Methods A total of 16 breast cancers confirmed by needle biopsy in 15 patients were included in this study from October 2012 to June 2014. Under ultrasonography (US)-guidance, the surgical clips were placed prior to NAC. Additional mammography, breast US, and breast magnetic resonance examinations were performed within 10 days before surgery. The time period from marker insertion to operation date was documented. Images acquired via the three modalities were evalu-ated for the following parameters: location of clip, clip migration (>1 cm), the presence of complications from clip placement, and the effect of clips on the assessment of treatment. Results The mean time period was 128.6±34.4 days (median, 132.0 days) from the date of clip insertion to the date of surgery. The mean number of inserted clips was 2.3±0.7 (median, 2.0). Clip migration was not visualized by imaging in any patient, and there were no complications reported. Surgical clips did not negatively affect the assessment of treatment responses to NAC. Conclusion Surgical clips may replace commercial tissue markers for tumor localization in breast cancer patients undergoing NAC without migration. Surgical clips are well tolerated and safe for the patient, easily visualized on imaging, do not interfere with treatment response, and are cost-effective.

Feasibility of Preoperative Axillary Lymph Node Marking with a Clip in Breast Cancer Patients Before Neoadjuvant Chemotherapy: A Preliminary Study

BackgroundThe aim of this study was to determine the feasibility of image-guided marker-clip placement in axillary lymph nodes (ALNs) for breast cancer upon initial presentation and to assess the reliability of this method with sentinel lymph node biopsy (SLNB) for axillary restaging after neoadjuvant chemotherapy (NAC).MethodsBetween June 2015 and August 2016, a marker clip was placed at a clinically positive ALN under ultrasonography (US) guidance before initiation of NAC in 20 patients. Preoperative localization of marker-clipped LNs was performed, and the localized LNs were removed by SLNB. We compared the postoperative results of the marker-clipped LNs, SLNs and ALNs.ResultsImage-guided marker-clip placements and localization of marker-clipped LNs were performed successfully in 20 patients. A total of 24 marker clips were inserted, and 23 marker-clipped LNs were successfully retrieved during surgery (identification rate, 23/24, 95.8%). In the 11 patients with pathologically confirmed metastatic marker-clipped LNs, four became negative after NAC, and seven maintained metastatic residues on the marker-clipped LNs. Three of the seven patients had metastatic residues on the ALNs, and two of the three patients also had negative SLNs. Marker-clipped nodes accurately predicted the axillary nodal status in these two patients compared with SLNs alone.ConclusionImage-guided marker-clip placement on positive ALNs before NAC and removal with SLNB is technically feasible. This technique can improve the accuracy of the residual disease evaluation on the axilla, especially in patients with negative SLNB results, and can identify candidates for limited axillary surgery after NAC.

Mammographic Breast Density Evaluation in Korean Women Using Fully Automated Volumetric Assessment

The purpose was to present mean breast density of Korean women according to age using fully automated volumetric assessment. This study included 5,967 screening normal or benign mammograms (mean age, 46.2 ± 9.7; range, 30–89 years), from cancer-screening program. We evaluated mean fibroglandular tissue volume, breast tissue volume, volumetric breast density (VBD), and the results were 53.7 ± 30.8 cm3, 383.8 ± 205.2 cm3, and 15.8% ± 7.3%. The frequency of dense breasts and mean VBD by age group were 94.3% and 19.1% ± 6.7% for the 30s (n = 1,484), 91.4% and 17.2% ± 6.8% for the 40s (n = 2,706), 72.2% and 12.4% ± 6.2% for the 50s (n = 1,138), 44.0% and 8.6% ± 4.3% for the 60s (n = 89), 39.1% and 8.0% ± 3.8% for the 70s (n = 138), and 39.1% and 8.0% ± 3.5% for the 80s (n = 12). The frequency of dense breasts was higher in younger women (n = 4,313, 92.3%) than older women (n = 1,654, 59.8%). Mean VBD decreased with aging or menopause, and was about 16% for 46-year-old-Korean women, much higher than in other countries. The proportion of dense breasts sharply decreases in Korean women between 40 and 69 years of age.

Evaluation of Screening US–detected Breast Masses by Combined Use of Elastography and Color Doppler US with B-Mode US in Women with Dense Breasts: A Multicenter Prospective Study

Purpose To investigate the value of the combined use of elastography and color Doppler ultrasonography (US) with B-mode US for evaluation of screening US-detected breast masses in women with dense breasts. Materials and Methods This prospective, multicenter study included asymptomatic women with dense breasts who were referred for screening US between November 2013 and December 2014. Eligible women had a newly detected breast mass at conventional B-mode US screening, for which elastography and color Doppler US were performed. The following outcome measures were compared between B-mode US and the combination of B-mode US, elastography, and color Doppler US: area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive predictive value (PPV), and the number of false-positive findings at screening US. Results Among 1021 breast masses (mean size, 1.0 cm; range, 0.3-3.0 cm) in 1021 women (median age, 45 years), 68 were malignant (56 invasive). Addition of elastography and color Doppler US to B-mode US increased the AUC from 0.87 (95% confidence interval [CI]: 0.82, 0.91) to 0.96 (95% CI: 0.95, 0.98; P < .001); specificity from 27.0% (95% CI: 24.2%, 29.9%) to 76.4% (95% CI: 73.6%, 79.1%; P < .001) without loss in sensitivity (95% CI: -1.5%, 1.5%; P > .999); and PPV from 8.9% (95% CI: 7.0%, 11.2%) to 23.2% (95% CI: 18.5%, 28.5%; P < .001), while avoiding 67.7% (471 of 696) of unnecessary biopsies for nonmalignant lesions. Conclusion Addition of elastography and color Doppler US to B-mode US can increase the PPV of screening US in women with dense breasts while reducing the number of false-positive findings without missing cancers.

Impact of high-grade obstruction on outcomes in patients with appendiceal inflammatory masses managed by nonoperative treatment

Purpose To retrospectively assess the impact of high-grade obstructions identified on initial CT on outcomes of patients with appendiceal inflammatory masses managed by nonoperative treatment. Methods Institutional Review Boards approved this retrospective study and informed consent was waived. Included were 52 consecutive patients diagnosed with appendiceal inflammatory masses by CT scan and managed by nonoperative treatment. The main outcome measure was treatment failure and secondary outcomes were complications and initial and total hospital stay. Patient demographics, inflammatory markers, and CT findings for presence of an appendiceal inflammatory mass and high-grade obstruction were assessed. Patients with and without high-grade obstruction were compared for patient characteristics and outcomes using Fisher exact test and Student t-test. Results Among 52 patients, 14 (27%) had high-grade obstruction on CT examination at presentation. No significant differences were observed in patient characteristics (P > 0.05), treatment failure (P = 0.33), complications (P = 0.29), or initial (P = 0.73) or total (P = 0.72) hospitalization between patients with and without high-grade obstruction. Conclusion For patients who were managed by nonoperative treatment for appendiceal inflammatory masses, the presence of high-grade obstruction identified on initial CT scan did not significantly affect outcomes of treatment failure, complications, and initial and total hospitalization.