Kyung Hee Ko

CHA University, Sŏul, Seoul, South Korea

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Publications (27)44.51 Total impact

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    ABSTRACT: 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.
    Ultrasonography (Seoul, Korea). 01/2014; 33(1):3-10.
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    ABSTRACT: PURPOSE To evaluate the usefulness of SWE for the differential Diagnosis of small (≤2cm) breast lesions METHOD AND MATERIALS From June 2012 to December 2012, of 215 women who had been performed conventional US and SWE, 165 masses of 155 women (mean age: 44.97±9.54 years, range 22-87 years) who had 2cm and smaller lesions were included in this study. All patients underwent US guided core biopsy or surgical excision. US BI-RADS final assessment and quantitative SWE parameters were recorded. Final assessments of the 165 breast lesions were categorized as follows: category 3 in 23, category 4a in 119, category 4b in 11, category 4c in 8, and category 5 in 4. Histopathologic diagnosis was used as reference standard. Optimal cutoff value for each quantitative SWE parameter was calculated by ROC curve. Calculated cutoff value was used to upgrade BI-RADS 3 lesions to category 4a and downgrade BI-RADS 4a lesions to category 3. RESULTS Of the 165 small breast masses, 20 masses (12%) were malignant and 145 masses (88%) were benign. Mean Emax of malignant masses (141.97±98.03kPA) was significantly higher than that of benign (49.14±39.89kPa). Emax with a cutoff value of 87.5kPa had the highest Az value (0.796, sensitivity 75.0%, specificity 85.5%, PPV 41.7%, NPV 96.1%). However, for small masses equal or smaller than 1cm, Az values of all quantitative SWE parameters were lower than 0.6. After adding SWE to conventional US, there was no improvement of diagnostic performance (sensitivity 80%, specificity 95.2%, PPV 69.6%, NPV 97.2%). When applying Emax <87.5 to downgrade BI-RADS category 4a to BI-RADS category 3, we could reduce benign biopsy rate from 84 %(102/122) to 62 %(26/42). CONCLUSION Small malignant masses≤2cm were significantly stiffer than small benign lesions. However adding SWE parameters to conventional US showed no improvement of diagnostic performance. SWE could give US BI-RADS some help for reducing benign biopsy rate. CLINICAL RELEVANCE/APPLICATION SWE could give conventioanl US BI-RADS some help on differential diagnosis of small breast masses 2cm or smaller with reducing benign biopsy rate.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: To report our preliminary experience with shear-wave elastography (SWE) for non-mass lesions (NMLs) in the breast and suggest a potential ancillary role of SWE for BI-RADS Category 4a NMLs in reducing the number of unnecessary benign biopsies. A total of 310 breast lesions in 286 consecutive women who had been scheduled for US-guided automated gun biopsy or vacuum-assisted biopsy between June and December 2012 were initially included in this study. Finally, 33 women with 34 breast lesions classified as NMLs constituted our study population. Diagnostic performances of each quantitative SWE parameter were calculated. Histological diagnosis was used as a reference standard. Among the 34 breast NMLs, 22 (65 %) were benign and 12 (35 %) were malignant. Emean value with cut-off set at 41.6 kPa had the highest Az value 0.788 (95 % CI, 0.625-0.951), showing sensitivity of 83.3 % and specificity of 68.2 %. By applying an Emean value of 41.6 kPa or less as a criterion for downgrading soft BI-RADS category 4a NMLs to category 3 NMLs, 15 unnecessary biopsies could have been eliminated from the 19 BI-RADS category 4a lesions (79 %). SWE features could increase positive predictive values and reduce unnecessary benign biopsies of category 4a NMLs. • Ultrasound elastography is increasingly used to assess the stiffness of breast lesions • Shear-wave elastography provides useful information about non-mass breast lesions • Shear-wave elastography may render some biopsies of non-mass breast lesions unnecessary.
    European Radiology 10/2013; · 4.34 Impact Factor
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    ABSTRACT: To determine the correlation of qualitative shear wave elastography (SWE) pattern classification to quantitative SWE measurements and whether it is representative of quantitative SWE values with similar performances. From October 2012 to January 2013, 267 breast masses of 236 women (mean age: 45.12±10.54 years, range: 21-88 years) who had undergone ultrasonography (US), SWE, and subsequent biopsy were included. US BI-RADS final assessment and qualitative and quantitative SWE measurements were recorded. Correlation between pattern classification and mean elasticity, maximum elasticity, elasticity ratio and standard deviation were evaluated. Diagnostic performances of grayscale US, SWE parameters, and US combined to SWE values were calculated and compared. Of the 267 breast masses, 208 (77.9%) were benign and 59 (22.1%) were malignant. Pattern classifications significantly correlated with all quantitative SWE measurements, showing highest correlation with maximum elasticity, r=0.721 (P<0.001). Sensitivity was significantly decreased in US combined to SWE measurements to grayscale US: 69.5-89.8% to 100.0%, while specificity was significantly improved: 62.5-81.7% to 13.9% (P<0.001). Area under the ROC curve (Az) did not show significant differences between grayscale US to US combined to SWE (P>0.05). Pattern classification shows high correlation to maximum stiffness and may be representative of quantitative SWE values. When combined to grayscale US, SWE improves specificity of US.
    European journal of radiology 09/2013; · 2.65 Impact Factor
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    ABSTRACT: The goal of this study is to compare the overall quality of film mammograms taken according to the Korean standards with the American College of Radiology (ACR) standard for clinical image evaluation and to identify means of improving mammography quality in Korea. Four hundred and sixty eight sets of film mammograms were evaluated with respect to the Korean and ACR standards for clinical image evaluation. The pass and failure rates of mammograms were compared by medical facility types. Average scores in each category of the two standards were evaluated. Receiver operating characteristic curve analysis was used to identify an optimal Korean standard pass mark by taking the ACR standard as the reference standard. 93.6% (438/468) of mammograms passed the Korean standard, whereas only 80.1% (375/468) passed the ACR standard (p < 0.001). Non-radiologic private clinics had the lowest pass rate (88.1%: Korean standard, 71.8%: ACR standard) and the lowest total score (76.0) by the Korean standard. Average scores of positioning were lowest (19.3/29 by the Korean standard and 3.7/5 by the ACR standard). A cutoff score of 77.0 for the Korean standard was found to correspond to a pass level when the ACR standard was applied. We suggest that tighter regulations, such as, raising the Korean pass mark, subtracting more for severe deficiencies, or considering a very low scores in even a single category as failure, are needed to improve the quality of mammography in Korea.
    Korean journal of radiology: official journal of the Korean Radiological Society 09/2013; 14(5):701-10. · 1.32 Impact Factor
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    ABSTRACT: OBJECTIVE: To investigate the factors that have an effect on false-positive or false-negative shear-wave elastography (SWE) results in solid breast masses. METHODS: From June to December 2012, 222 breast lesions of 199 consecutive women (mean age: 45.3 ± 10.1 years; range, 21 to 88 years) who had been scheduled for biopsy or surgical excision were included. Greyscale ultrasound and SWE were performed in all women before biopsy. Final ultrasound assessments and SWE parameters (pattern classification and maximum elasticity) were recorded and compared with histopathology results. Patient and lesion factors in the 'true' and 'false' groups were compared. RESULTS: Of the 222 masses, 175 (78.8 %) were benign, and 47 (21.2 %) were malignant. False-positive rates of benign masses were significantly higher than false-negative rates of malignancy in SWE patterns, 36.6 % to 6.4 % (P < 0.001). Among both benign and malignant masses, factors showing significance among false SWE features were lesion size, breast thickness and lesion depth (all P < 0.05). All 47 malignant breast masses had SWE images of good quality. CONCLUSIONS: False SWE features were more significantly seen in benign masses. Lesion size, breast thickness and lesion depth have significance in producing false results, and this needs consideration in SWE image acquisition. KEY POINTS: • Shear-wave elastography (SWE) is widely used during breast imaging • At SWE, false-positive rates were significantly higher than false-negative rates • Larger size, breast thickness, depth and fair quality influences false-positive SWE features • Smaller size, larger breast thickness and depth influences false-negative SWE features.
    European Radiology 05/2013; · 4.34 Impact Factor
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    ABSTRACT: OBJECTIVE: To evaluate which shear wave elastography (SWE) parameter proves most accurate in the differential diagnosis of solid breast masses. METHODS: One hundred and fifty-six breast lesions in 139 consecutive women (mean age: 43.54 ± 9.94 years, range 21-88 years), who had been scheduled for ultrasound-guided breast biopsy, were included. Conventional ultrasound and SWE were performed in all women before biopsy procedures. Ultrasound BI-RADS final assessment and SWE parameters were recorded. Diagnostic performance of each SWE parameter was calculated and compared with those obtained when applying cut-off values of previously published data. Performance of conventional ultrasound and ultrasound combined with each parameter was also compared. RESULTS: Of the 156 breast masses, 120 (76.9 %) were benign and 36 (23.1 %) malignant. Maximum stiffness (Emax) with a cut-off of 82.3 kPa had the highest area under the receiver operating characteristics curve (Az) value compared with other SWE parameters, 0.860 (sensitivity 88.9 %, specificity 77.5 %, accuracy 80.1 %). Az values of conventional ultrasound combined with each SWE parameter showed lower (but not significantly) values than with conventional ultrasound alone. CONCLUSIONS: Maximum stiffness (82.3 kPa) provided the best diagnostic performance. However the overall diagnostic performance of ultrasound plus SWE was not significantly better than that of conventional ultrasound alone. KEY POINTS : • SWE offers new information over and above conventional breast ultrasound • Various SWE parameters were explored regarding distinction between benign and malignant lesions • An elasticity of 82.3 kPa appears optimal in differentiating solid breast masses • However, ultrasound plus SWE was not significantly better than conventional ultrasound alone.
    European Radiology 02/2013; · 4.34 Impact Factor
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    Kyung Hee Ko, Hye Kyoung Jung, Tae Joo Jeon
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    ABSTRACT: We present an interesting case of incidental diffuse fluorodeoxyglucose (FDG) uptake at PET in her left breast, related to atypical breastfeeding practice. Clinically, differential diagnoses of diffuse intense FDG uptake in unilateral breast include advanced breast cancer, breast lymphoma and inflammatory condition. However, normal physiologic lactation may also show increased FDG uptake in the breasts. Therefore, if we encounter that finding in daily practice, we should question the patient regarding unilateral breastfeeding. In addition, mammography and ultrasound would be helpful to confirm the diagnosis.
    Korean journal of radiology: official journal of the Korean Radiological Society 01/2013; 14(3):400-402. · 1.32 Impact Factor
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    ABSTRACT: The study objective was to evaluate our experiences of ultrasound-guided vacuum-assisted excision (US-VAE) of benign intraductal papillomas, and to discuss its potential application as a minimally invasive treatment We reviewed the sonographic and histologic features of 29 benign intraductal papillomas removed by US-VAE. The procedure was recommended on the basis of our indications. For validation of selection criteria, the sonographic and pathologic characteristics of surgically excised 94 papillary lesions during the same period were also evaluated. The mean diameter of the lesions was 9.8 mm (range 5-15 mm). There was no mass that abutted the skin or pectoralis muscle and extended the branching ducts. All lesions were category 3 or category 4a. The pathologic diagnoses of all removed masses were benign. Local recurrence was observed in one patient. According to the validation study, papillary lesions less than 1.5 cm of category 3 or 4a were mostly reported to be benign (95.9%, 47 of 49). US-VAE may be a useful alternative to surgical excision in well-selected benign intraductal papillomas.
    Annals of Surgical Oncology 09/2011; 19(3):908-13. · 4.12 Impact Factor
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    ABSTRACT: An imaging-guided core needle biopsy has been proven to be reliable and accurate for the diagnosis of both benign and malignant diseases of the breast, and has replaced surgical biopsy. However, the possibility of a false-negative biopsy still remains. Imaging-pathology correlation is of critical importance in imaging-guided breast biopsies to detect such a possible sampling error and avoid a delay in diagnosis. We will review five possible categories and corresponding management after performing an imaging-pathology correlation in a sonography-guided core needle biopsy of a breast lesion, as well as illustrate the selected images for each category in conjunction with the pathologic finding. Radiologists should be familiar with the imaging features of various breast pathologies and be able to appropriately correlate imaging findings with pathologic results after a core needle biopsy.
    Korean journal of radiology: official journal of the Korean Radiological Society 03/2011; 12(2):232-40. · 1.32 Impact Factor
  • Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 11/2010; 29(11):1671-4. · 1.40 Impact Factor
  • Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 08/2009; 28(7):973-6. · 1.40 Impact Factor
  • Kyung Hee Ko, Ji Hyun Youk, Eun Ju Son
    Ultrasound in Medicine and Biology - ULTRASOUND MED BIOL. 01/2009; 35(8).
  • Ultrasound in Medicine and Biology - ULTRASOUND MED BIOL. 01/2009; 35(8).
  • Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 01/2009; 27(12):1771-5. · 1.40 Impact Factor
  • Ultrasound in Medicine and Biology - ULTRASOUND MED BIOL. 01/2009; 35(8).
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    ABSTRACT: Asymmetric breast findings are frequently encountered at screening and diagnostic mammography. However, there has been some confusion about the applicable terminology for describing asymmetric breast findings. The fourth edition of the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) has incorporated changes in the lexicon for asymmetric breast findings to address such problems and improve the clinical utility of reporting. The fourth edition has replaced "asymmetric breast tissue" with "global asymmetry," "density seen in only a single projection" with "asymmetry," and "focal asymmetric density" with "focal asymmetry." Once an asymmetric finding is perceived, it should be determined whether it is due to a definite lesion. To interpret and manage asymmetric breast findings, additional imaging studies such as straight lateral views, rolled views, and spot compression views at mammography and ultrasonography or magnetic resonance imaging should be applied appropriately in a logical work flow, and the radiologist should be aware of the pitfalls and pearls of each technique and modality.
    Radiographics 12/2008; 29(1):e33. · 2.79 Impact Factor
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    ABSTRACT: The purpose of this study was to document the sonographic findings of axillary lymphadenopathy in Kikuchi disease. The medical records and sonographic findings of 7 patients with a pathologic diagnosis of Kikuchi disease in the axillary lymph node by sonographically guided core needle biopsy (n=6) or excisional biopsy (n=1) were reviewed. On sonograms, lymph nodes were assessed for their distribution, size, shape, border, echogenicity, and internal architecture, and those sonographic features of each node were evaluated to determine whether the findings favored malignant or benign lymphadenopathy. Of the 7 patients (1 man and 6 women; mean age +/- SD, 34.3+/-7.7 years), 29 affected lymph nodes (5-38 mm; mean, 14.8+/-7.2 mm) were identified on sonograms. The sonographic characteristics were as follows: the shortest axis/longest axis ratio of the node (mean, 0.595) was 0.5 or greater in 22 nodes (76%); the border was sharp in 16 (55%); the cortex was hypoechoic in 20 (69%) and isoechoic in 9 (31%); the hilum was narrow in 1 (4%) and absent in 16 (55%); and cortical thickening was found in 13 (45%, concentric in 6 and eccentric in 7). Nineteen lymph nodes (66%) were classified as having malignant-favoring features, and 10 (34%) were classified as having benign-favoring features. Many axillary lymph nodes in Kikuchi disease look suspicious sonographically. When lymph nodes in the axilla show suspicious findings on sonograms of relatively young patients, Kikuchi disease can be considered a possible differential diagnosis, and image-guided percutaneous biopsy should be done.
    Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 07/2008; 27(6):847-53. · 1.40 Impact Factor
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    ABSTRACT: The objective of our study was to report the results of classification of sonographic findings according to BI-RADS and to calculate the positive predictive value (PPV) for each BI-RADS assessment category. We prospectively classified 4,668 breast sonograms according to BI-RADS final assessment category. Suspicious sonographic findings were divided into major and minor suspicious findings. Category 1 was normal and category 2 was a benign finding such as cyst or nodule with uniform and intense hyperechogenicity. A nodule neither category 2 nor category 4 or 5 was defined as category 3. A nodule with one or more suspicious findings, not category 5, was defined as category 4. A nodule with two or more major suspicious findings was defined as category 5. Of the 4,668 cases, 321 cases failed to undergo follow-up of at least 1 year. The PPV was 0.1% in category 1 (3/2,191), 0% in category 2 (0/773), 0.8% in category 3 (6/737), 31.1% in category 4 (161/519), and 96.9% in category 5 (123/127). In palpable lesions (n = 751), the PPV was 2.2% in category 1 (2/93), 0.9% in category 3 (2/217), 54% in category 4 (107/198), and 98% in category 5 (98/100). In nonpalpable lesions (n = 3,596), the PPV was 0.05% in category 1 (1/2,098), 0.8% in category 3 (4/520), 16.8% in category 4 (54/321), and 92.6% in category 5 (25/27). As with mammography, placing sonographic lesions into BI-RADS categories is useful for predicting the presence of malignancy.
    American Journal of Roentgenology 06/2008; 190(5):1209-15. · 2.90 Impact Factor
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    ABSTRACT: To evaluate the safety and efficiency of the Ultrasound (US)-guided large needle core biopsy of axilla lymph nodes. From March 2004 to September 2005, 31 patients underwent the US-guided core biopsy for axilla lymph nodes. Twenty five lesions out of 31 were detected during breast US, and 6 of 31 cases were palpable. Lymph nodes were classified based on their shape and cortical morphology. The core biopsy of axilla lymph nodes was performed on suspicious lymph nodes found during breast ultrasonography to find out whether the patients had a history of breast cancer or not. Among the 31 patients, 16 patients were associated with breast cancer. The lesion sizes varied from 0.6 cm to 3.3 cm (mean=1.59+/-0.76 cm). US-guided core biopsies were performed with 14 G needles with an automated biopsy gun. Total 3 or 5 specimens were obtained. Among the 31 cases of axilla lymph nodes core biopsies, 11 cases showed malignant pathology. Seven out of 11 cases were metastatic lymph nodes from breast cancer; 2 cases were from primary unknown and 2 cases from lymphomas. On the other hand, 20 histopathologic results of axilla lesions were benign: subacute necrotizing lymphadenitis (n=2), dermatopathic lymphadenitis (n=1), reactive hyperplasia (n=10) and free of carcinoma (n=7). The US-guided large needle core biopsy of axilla lesions is safe and effective for the pathological evaluation. The core biopsy is believed to be easy to perform if suspicious lymph nodes or mass lesions are found in the axilla.
    Yonsei Medical Journal 05/2008; 49(2):249-54. · 1.31 Impact Factor