Mitsuhiro Tozaki

Kameda Medical Center, Kameda, Niigata, Japan

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Publications (80)88.98 Total impact

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    ABSTRACT: Purpose To compare positive predictive values (PPVs) of linearly distributed nonmass enhancement (NME) with linear and branching patterns and to identify imaging characteristics of NME that would enable classification as Breast Imaging Reporting and Data System category 3 lesions. Materials and Methods The institutional review board approved this retrospective study and waived the requirement to obtain informed consent. Reports of breast magnetic resonance (MR) examinations (n = 9453) that described NME were reviewed from examinations performed at the study institution from January 2008 to December 2011. NME with linear distribution was allocated to one of two subtypes: linear pattern (arrayed in a line) or branching pattern (with branches). The χ(2) test, Fisher exact test, or Student t test was performed for univariate analyses. Factors that showed a significant association with outcome at univariate analyses were assessed with multivariate analyses by using a logistic regression model. Interobserver agreement of the two subtypes between initial interpretation and the interpretation by two additional radiologists who were blinded to any clinical or pathologic information was evaluated with κ analysis. Results Within the 156 linearly distributed NME lesions, the PPV of the branching pattern (71 of 95 lesions [75%]; 95% confidence interval [CI]: 66%, 84%) was significantly higher than that of the linear pattern (five of 61 lesions [8%]; 95% CI: 1%, 15%) (P < .0001). The PPV of linear pattern lesions smaller than 1 cm was 0% (0 of 30 lesions; 95% CI: 0%, 0%). At multivariate analysis, branching pattern and NME lesion size of 1 cm or greater were significant predictors of malignancy (P < .0001 [odds ratio: 21.6; 95% CI: 7.5, 62.2] and P = .015 [odds ratio: 5.8; 95% CI: 1.4, 24.0], respectively). Substantial interobserver agreement was obtained for differentiating the two subtypes, with κ values of 0.64 (95% CI: 0.51, 0.76), 0.70 (95% CI: 0.59, 0.82), and 0.64 (95% CI: 0.51, 0.76) between the initial interpreter and reviewer 1, the initial interpreter and reviewer 2, and reviewer 1 and reviewer 2, respectively. Conclusion The branching pattern was a significantly stronger predictor of malignancy than was the linear pattern. NME lesions with a linear pattern that are smaller than 1 cm can be managed with follow-up. (©) RSNA, 2015.
    Radiology 04/2015; DOI:10.1148/radiol.2015141775 · 6.21 Impact Factor
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    ABSTRACT: The primary modality for breast cancer screening is mammography. Recent investigations, however, have indicated that an insufficient number of life-threatening cases have been detected by mammography while mammography can often results in a large number of overdiagnoses. To make breast cancer screening more effective, potential factors that influence screening efficacy need to be elucidated. Breast density is one of limiting factors for breast cancer detection using mammography. In this article, influence of breast density on breast screening is explained. Current topics related to breast density, objective assessment of breast density using applications, revision of breast composition classification in Breast Imaging-Reporting and Data System Mammography fifth edition, and legislative movement regarding breast density in the United States, are also mentioned in this review article.
    Breast Cancer 03/2015; 22(3). DOI:10.1007/s12282-015-0602-2 · 1.51 Impact Factor
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    ABSTRACT: To demonstrate the noninferiority of gadobutrol-enhanced magnetic resonance imaging (MRI) compared with gadopentetate dimeglumine-enhanced MRI in Asian patients referred for contrast-enhanced imaging of the body or extremities. A multicenter, parallel-group comparison study of Asian adults referred for contrast-enhanced MRI were randomized (1:1) to either gadobutrol or gadopentetate dimeglumine. Lesions were assessed for three primary visualization variables: degree of contrast enhancement, border delineation, and internal morphology. Secondary efficacy variables included number of lesions detected, match of MRI diagnosis with final clinical diagnosis, and sensitivity and specificity for malignant lesion detection. Safety was monitored for 24 ± 4 hours after contrast agent administration. A total of 363 patients received either gadobutrol (n = 168) or gadopentetate dimeglumine (n = 178). Mean total scores for three primary visualization variables were 9.39 and 9.34 for gadobutrol and gadopentetate dimeglumine, respectively. The proportion of patients with matched MRI and final diagnosis and sensitivity for malignant lesion detection was greater for unenhanced versus combined images (gadobutrol: 72.2% vs. 81.7%; gadopentetate dimeglumine: 76.2% vs. 82.2%, respectively). Both contrast agents were well tolerated. Gadobutrol (0.1 mmol/kg BW) was well tolerated and effective in Asian patients referred for contrast-enhanced MRI of the body or extremities.J. Magn. Reson. Imaging 2014. © 2014 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 02/2015; 41(2). DOI:10.1002/jmri.24566 · 2.79 Impact Factor
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    ABSTRACT: ScreeningFor reference: Categorization in the Japanese mammography guidelines and those of the Breast Imaging Reporting and Data SystemThe Breast Imaging Reporting and Data System (BI-RADS) developed by the American College of Radiology (ACR) as a standardized quality assessment tool for drawing up imaging findings and reports is universally recognized. In Japan, the “Guidelines for Mammography” complied on the basis of the 2nd edition of BI-RADS were published in 1999. According to those guidelines, mammogram findings are finally assessed for malignancy using 5 grading categories, i.e., category 1 or 2 requiring no additional detailed examination and categories 3–5 warranting further detailed examinations.The 4th edition of BI-RADS [1], on the other hand, is designed to provide a general flow of the breast cancer screening process as follows: lesions presenting screening mammographic findings based on which malignancy cannot be negated are classified into category 0 and subjected to d ...
    Breast Cancer 08/2014; DOI:10.1007/s12282-014-0557-8 · 1.51 Impact Factor
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    ABSTRACT: To evaluate the clinical feasibility of breast density measurements by a new application within a direct photon-counting mammography scanner system. A retrospective study of consecutive women who underwent mammography using a direct photon-counting mammography scanner system (MicroDose mammography SI; Philips Digital Mammography Sweden AB) was performed at the authors' institution between September and December 2013. Quantitative volumetric glandularity measurements were performed automatically for each acquired mammographic image using an application (Breast Density Measurement; Philips Digital Mammography Sweden AB). The quantitative volumetric glandularity of each breast was defined as the average values for the mediolateral oblique (MLO) and craniocaudal (CC) mammogram views. Of the 44 women who underwent bilateral mammogram acquisitions, the breast density measurements were performed successfully in 40 patients (90.9 %). A very good to excellent correlation in the quantitative breast density measurements acquired from the MLO and CC images was obtained in the 40 evaluable patients (R = 0.99). The calculated volumetric glandularity using this new application should correspond well with the true volumetric density of each breast.
    Japanese journal of radiology 05/2014; 32(9). DOI:10.1007/s11604-014-0333-x · 0.74 Impact Factor
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    ABSTRACT: Some reports suggest that the rate of definitive diagnosis of malignant tumors, namely, the final diagnosis being revised to a higher stage, in patients diagnosed as having flat epithelial atypia (FEA) by percutaneous needle biopsy of the breast (PNB) is as low as 0-3 %. However, other reports suggest that the rate is as high as 10 % or more, bringing confusion on this issue. We examined the positive predictive value for malignancy in the patients diagnosed as having pure FEA and the patients' radiolopathological characteristics observed in our hospital. Of the patients who underwent PNB in our facility, those who were diagnosed as having pure FEA were recruited as the subjects of this study. Of the 4,197 consecutive patients who underwent PNB, 44 (1.0 %) were diagnosed as having pure FEA following a re-examination. Among 44 cases, 39 cases were selected as the subjects of this study. Among the 39 patients, six patients were diagnosed as having malignant lesions, two of whom had invasive carcinoma of no special type (papillotubular type), one had tubular carcinoma, one had ductal carcinoma in situ (DCIS) of high nuclear grade, one had DCIS of intermediate nuclear grade, and one had DCIS of low nuclear grade. The diameters of 6 malignant lesions were 10-30 mm at ultrasonography (US) examination. Five of the 39 patients had contralateral breast cancer. The positive predictive value for malignancy of pure FEA was 15.7 %. The patients with pure FEA may make a follow up without an excisional biopsy when the lesion sizes less than 10 mm on US examination.
    Breast Cancer 04/2014; DOI:10.1007/s12282-014-0530-6 · 1.51 Impact Factor
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    ABSTRACT: We assembled needed data on the prevalence and characteristics of BRCA1/2 in Japan. Our study of BRCA1/2 collected data at eight institutions in Japan on 320 individuals with a strong family history of breast cancer, according to the NCCN guidelines, by the end of March 2012. Among 260 proband cases, 46 (17.7 %) were positive for BRCA1, and 35 (13.5 %) were BRCA2-positive. Therefore, the total pathological mutation rate was 30.7 %. Pathology data after breast surgery were obtained from 37 cases of BRCA1 mutation, 23 (62.2 %) of which were triple negative (TN). On the other hand, 29 cases (82.9 %) of BRCA2 mutations were Luminal type. The most prevalent BRCA1 mutation site was L63X, found in 10 families. L63X was reported previously by studies in Japan, and it may be a founder mutation. We found two cases of large deletion detected by multiplex ligation-dependent probe amplification. One was an entire deletion of exon 20 and the lacked exons 1-9. TN with a family history of ovarian cancer was 11/20 (55 %). TN under 40-year-old (y.o.) 15/23 (65.2 %) and TN with one or more breast cancers in family history 17/32 (53.1 %) showed higher incidences of BRCA1 mutation. Hereditary breast and ovarian cancer (HBOC) may have nearly the same prevalence in Japan as in the US or Europe. If TN cases are taken into account, the ratio of BRCA1 is higher. L63X may be one of the founder mutations in Japan. A nationwide database of HBOC is important to develop risk models for BRCA1/2 carriers in Japan.
    Breast Cancer 11/2013; DOI:10.1007/s12282-013-0503-1 · 1.51 Impact Factor
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    ABSTRACT: This study compared the diagnostic performance of two shear wave speed measurement techniques in 81 patients with 83 solid breast lesions. Virtual Touch Quantification, which provides single-point shear wave speed measurement capability (SP-SWS), was compared with Virtual Touch IQ, a new 2-D shear wave imaging technique with multi-point shear wave speed measurement capability (2D-SWS). With SP-SWS, shear wave velocity was measured within the lesion ("internal" value) and the marginal areas ("marginal" value). With 2D-SWS, the highest velocity was measured. The marginal values obtained with the SP-SWS and 2D-SWS methods were significantly higher for malignant lesions and benign lesions, respectively (p < 0.0001). Sensitivity, specificity and accuracy were 86% (36/42), 90% (37/41) and 88% (73/83), respectively, for SP-SWS, and 88% (37/42), 93% (38/41) and 90% (75/83), respectively, for 2D-SWS. It is concluded that 2D-SWS is a useful diagnostic tool for differentiating malignant from benign solid breast masses.
    Ultrasound in medicine & biology 09/2013; DOI:10.1016/j.ultrasmedbio.2013.07.012 · 2.10 Impact Factor
  • Nihon Nyugan Kenshin Gakkaishi (Journal of Japan Association of Breast Cancer Screening) 01/2013; 22(2):198-202. DOI:10.3804/jjabcs.22.198
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    ABSTRACT: Breast magnetic resonance imaging (MRI) has gained acceptance for detecting breast cancer at an earlier stage than mammography, and is expected to make a significant contribution to breast cancer screening. However, as MRI is costlier, less available, and relatively more invasive than mammography, it is not a suitable method for screening of the general population. However,current evidence suggests that women with a high risk of developing breast cancer are not rare in the Japanese population, and that such women develop breast cancer at a younger age when mammography is not so accurate for detection of early breast cancer. The present guidelines are designed to optimize the use of MRI for breast cancer screening in high-risk women. The issues covered background indications, technical factors that affect image quality, and interpretation. The main content is based on the breast MRI guidelines issued by the American College of Radiology (ACR) and the European Society of Breast Imaging (EUSOBI). With regard to technical factors, intravenous contrast study is defined as the standard methodology. Also the importance of examination timing is emphasized. To avoid physiological enhancement of normal breast tissue, MRI should be performed within10days after the end of menstruation. This is especially important for younger women at high risk. Non-contrast MRI including diffusion-weighted imaging is not recommended for this purpose because there is no definite evidence that has higher sensitivity to detect earlier breast cancer. In accordance with these guidelines, it is expected that optimal methodology for breast MRI will be adopted throughout Japan, thus reducing the breast cancer mortality rate among high-risk women.
    Nihon Nyugan Kenshin Gakkaishi (Journal of Japan Association of Breast Cancer Screening) 01/2013; 22(2):155-176. DOI:10.3804/jjabcs.22.155
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    ABSTRACT: Data reviewed at the Kyoto Breast Cancer Consensus Conference (KBCCC) showed that preoperative systemic therapy (PST) could optimize surgery through the utilization of information relating to pre- and post-PST tumor stage, therapeutic sensitivity, and treatment-induced changes in the biological characteristics of the tumor. As such, it was noted that the biological characteristics of the tumor, such as hormone receptors, human epidermal growth factor receptor-2, histological grade, cell proliferative activity, mainly defined by the Ki67 labeling index, and the tumor's multi-gene signature, should be considered in the planning of both systemic and local therapy. Furthermore, the timing of axillary sentinel lymph node diagnosis (i.e., before or after the PST) was also noted to be critical in that it may influence the likelihood of axillary preservation, even in node positive cases. In addition, axillary diagnosis with ultrasound and concomitant fine needle aspiration cytology or core needle biopsy (CNB) was reported to contribute to the construction of a treatment algorithm for patient-specific or individualized axillary surgery. Following PST, planning for breast surgery should therefore be based on tumor subtype, tumor volume and extent, therapeutic response to PST, and patient preference. Nomograms for predicting nodal status and drug sensitivity were also recognized as a tool to support decision-making in the selection of surgical treatment. Overall, review of data at the KBCCC showed that PST increases the likelihood of patients receiving localized surgery and individualized treatment regimens.
    Breast Cancer Research and Treatment 11/2012; 136(3). DOI:10.1007/s10549-012-2333-9 · 4.20 Impact Factor
  • Mitsuhiro Tozaki, Masaaki Sakamoto
    Nippon rinsho. Japanese journal of clinical medicine 09/2012; 70 Suppl 7:511-4.
  • Mitsuhiro Tozaki, Sachiko Isobe, Masaaki Sakamoto
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    ABSTRACT: We evaluated the diagnostic performance of elastography and tissue quantification using acoustic radiation force impulse (ARFI) technology for differential diagnosis of breast masses. There were 161 mass lesions. First, lesion correspondence on ARFI elastographic images to those on the B-mode images was evaluated: no findings on ARFI images (pattern 1), lesions that were bright inside (pattern 2), lesions that were dark inside (pattern 4), lesions that contained both bright and dark areas (pattern 3). In addition, pattern 4 was subdivided into 4a (dark area same as B-mode lesion) and 4b (dark area larger than lesion). Next, shear wave velocity (SWV) was measured using virtual touch tissue quantification. There were 13 pattern 1 lesions and five pattern 2 lesions; all of these lesions were benign, whereas all pattern 4b lesions (n = 43) were malignant. When the value of 3.59 m/s was chosen as the cutoff value, the combination of elastography and tissue quantification showed 91 % (83-91) sensitivity, 93 % (65-70) specificity, and 92 % (148-161) accuracy. The combination of elastography and tissue quantification is thought to be a promising ultrasound technique for differential diagnosis of breast-mass lesions.
    Japanese journal of radiology 07/2012; 30(8):659-70. DOI:10.1007/s11604-012-0106-3 · 0.74 Impact Factor
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    ABSTRACT: BACKGROUND: The purpose of this retrospective study was to examine the usefulness of MRI for predicting nipple involvement. METHODS: A retrospective review was performed of 81 breasts in 78 breast cancer patients who had undergone nipple or nipple-areolar complex resections during surgery. The enhancement patterns of the nipple on MRI were compared to the contralateral side and were categorized as no enhancement, bilateral enhancement, and unilateral enhancement. The physical examination results, MRI findings, and pathological findings were assessed. RESULTS: Nipple involvement was observed in 17 of 81 nipples (21%), of which one exhibited infiltration of invasive ductal carcinoma, 12 exhibited ductal carcinoma in situ, and four exhibited Paget's disease. The nipples with no enhancement or with bilateral enhancement on MRI showed a lower rate of nipple involvement than the nipples with unilateral enhancement (0/48 vs. 17/33, p < 0.001). Among the unilaterally enhanced nipples, those with continuous enhancement from the index lesion showed a higher rate of nipple involvement than those without continuous enhancement (16/26 vs. 1/7, p = 0.03). When the enhancement characteristics of the unilaterally enhanced nipples were categorized, the findings with relatively high positive predictive values for nipple involvement were diffuse enhancement (100%, 2/2), unilateral skin enhancement (100%, 2/2), rim enhancement (86%, 6/7), and periductal enhancement (80%, 4/5). CONCLUSIONS: MRI was useful for predicting nipple involvement. Unilateral enhancement of the nipple with continuous enhancement from the index lesion may suggest the possibility of nipple involvement.
    Breast Cancer 02/2012; 20(4). DOI:10.1007/s12282-012-0338-1 · 1.51 Impact Factor
  • Mitsuhiro Tozaki, Eisuke Fukuma
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    ABSTRACT: To assess the validity of categorization of ultrasonographic findings using automated breast ultrasonography (US). Bilateral whole-breast US was performed using an automated breast volume scanner (ABVS) in 400 women. The 3D data were evaluated using the ABVS workstation, and final assessment categories were recorded based on the following criteria. Irregular-shaped masses with a spiculated margin or echogenic halo were defined as category 5. Solid masses with one of the three suspicious findings (no circumscribed margin, no parallel orientation, and microcalcifications) were defined as category 4a, and masses with two or more suspicious findings were defined as category 4b. For non-mass lesions, localized hypoechoic areas with one of the three suspicious findings (segmental distribution, ductal change, and microcalcifications) were defined as category 4a. Localized hypoechoic areas with two or three suspicious findings were defined as category 4b or 5, respectively. Malignancy was confirmed histologically in 57 women (invasive, n = 38; in situ, n = 19). The rate of malignant findings was 0.6% (1/168) in category 3, 12% (15/129) in category 4a, 53% (31/59) in category 4b and 100% (10/10) in category 5. Categorization of ultrasonographic findings using automated breast US are useful for predicting the likelihood of malignancy.
    Japanese journal of radiology 12/2011; 30(2):185-91. DOI:10.1007/s11604-011-0028-5 · 0.74 Impact Factor
  • Mitsuhiro Tozaki, Eisuke Fukuma
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    ABSTRACT: ShearWave™ Elastography (SWE) provides a quantitative measurement of tissue stiffness and may improve characterization of breast masses. However, the significance of Young's modulus measurements and appropriate SWE evaluation criteria has not been established yet. To assess the usefulness of the pattern classification and Young's modulus measurements in the differential diagnosis between benign and malignant solid breast masses. Ninety-six patients (age range 18-84 years, mean 54 years) with 100 solid breast masses who underwent tissue sampling after a US examination were analyzed. We tried to create a visual pattern classification based on the SWE images. After classifying the visual patterns, the Young's modulus of the lesions was measured in every case. It was possible to classify the images into four patterns by the visual evaluation: no findings (coded blue homogeneously; Pattern 1), vertical stripe pattern artifacts (Pattern 2), a localized colored area at the margin of the lesion (Pattern 3), and heterogeneously colored areas in the interior of the lesion (Pattern 4). There were 17 Pattern 1 lesions, 14 Pattern 2 lesions, 20 Pattern 3 lesions, and 49 Pattern 4 lesions. When Patterns 1 and 2 were assumed to be benign, and Patterns 3 and 4 were assumed to be malignant, the sensitivity and specificity were 91.3% (63/69) and 80.6% (25/31), respectively. The mean Young's modulus measurements of the benign and the malignant lesions were 42 kPa and 146 kPa, respectively (P < 0.0001). No significant differences were found between benign and malignant lesions in Pattern 3. In Pattern 4, however, the Young's modulus of the benign lesions (50 kPa) was lower than the smallest Young's modulus of malignant lesions (61 kPa). The visual pattern classification and adding Young's modulus measurements may improve characterization of solid breast masses.
    Acta Radiologica 12/2011; 52(10):1069-75. DOI:10.1258/ar.2011.110276 · 1.35 Impact Factor
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    ABSTRACT: BACKGROUND: Parotid gland metastasis in breast cancer is extremely rare, and only 14 cases have been reported between 1982 and 2010. CASE REPORT: A 67-year-old female patient was diagnosed with invasive lobular carcinoma of the left breast. Although clinical staging was T1N3M1 (stage IV), the tumor experienced a complete response to chemotherapy. We therefore performed a mastectomy followed by radiotherapy, and continued administration of trastuzumab. However, 11 months later, the patient complained of a swelling in the left parotid gland. Histology following a partial parotidectomy revealed a parotid gland metastasis from the breast. CONCLUSION: Treatment with capecitabine in addition to trastuzumab, which is one of the strategies applied in HER2-positive breast cancer, was effective in our patient. Analysis of the 14 cases of parotid gland metastasis from the breast reported between 1982 and 2010 revealed that the metastasis may occur not by direct lymphatic but by hematogenous spread.
    Breast Care 12/2011; 6(6):471-473. DOI:10.1159/000335222 · 0.91 Impact Factor
  • Mitsuhiro Tozaki
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    ABSTRACT: There has been dramatic progress in MRI technology during the past 20 years, and the rate of detection and diagnostic accuracy in regard to intraductal carcinoma and ductal carcinoma in situ (DCIS) have been increasing. First, we present MRI images of intraductal carcinomas and the terminology in the second edition of the BI-RADS-MRI to describe them. Next, we examined the data in our institution in regard to the following: (1) the DCIS detection rate, (2) the proportions of breast cancer and DCIS in MR-guided vacuum-assisted biopsies (VAB), (3) evaluation of the extent of intraductal carcinoma, and (4) diagnosis of extension of intraductal carcinoma into the nipple. MR images were acquired by performing a 1-min interval dynamic study with a 1.5-T MR scanner. The same radiologist evaluated the MRI in all of the cases. MR-guided VAB was performed by using a commercially available biopsy system. (1) The DCIS detection rate was 95% (148/156), and the DCIS lesions that MRI was unable to detect were low grade in 5 cases, intermediate grade in 2 cases, and high grade in 1 case. (2) The proportion of MR-guided VAB specimens that were breast cancer was 36% (71/200), and the proportion of breast cancers that were DCIS was 82% (58/71). (3) The proportion of margin-positive specimens in the 100 breasts in which breast-conserving surgery was performed was 11% (11/100), and the proportion in which MRI was the cause of the margin being positive was a mere 4% (4/100). (4) The positive predictive value of periductal enhancement and linear enhancement for a diagnosis of intraductal extension into the nipple was 83% (10/12) and 43% (3/7), respectively. Their negative predictive value was 100% (58/58). We concluded that MRI is a very useful examination for the diagnosis of intraductal carcinoma, and that it is important to become thoroughly familiar with the BI-RADS-MRI terminology and accurate interpretation methods.
    Breast Cancer 11/2011; DOI:10.1007/s12282-011-0312-3 · 1.51 Impact Factor
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    ABSTRACT: The aim of this study was to perform the phantom experiment and demonstrate the clinical usefulness of tissue quantification using a linear array transducer and acoustic radiation force impulse (ARFI) technology. For the phantom study, the commercially available Elasticity QA Phantom Model 049 was used. First, we measured the shear wave velocity (m/s) for the four spheres and the background of the phantom. Then, the shear wave velocity at nine sites was measured, with the region of interest being moved gradually from a shallow region (3 mm) to a deeper region (38 mm). For the clinical study, the shear wave velocities of 15 solid breast mass lesions were measured. The phantom study confirmed the feasibility of quantitative determination of the degree of tissue hardness. Dispersion of the measured values tended to be somewhat increased for the depths of 3 mm and 38 mm. The mean shear wave velocity was 2.07-2.93 m/s for five benign lesions, whereas higher shear wave velocities (n = 2) (7.15, 7.44 m/s) or "X.XX" (unmeasurable state) (n = 7) were found for malignant lesions other than mucinous carcinoma (2.44 m/s). ARFI tissue quantification is a potentially promising ultrasonographic technique for diagnosing breast lesions.
    Japanese journal of radiology 10/2011; 29(8):598-603. DOI:10.1007/s11604-011-0591-9 · 0.74 Impact Factor
  • Mitsuhiro Tozaki, Sachiko Isobe, Eisuke Fukuma
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    ABSTRACT: To investigate the shear wave velocity of normal breast tissue and breast lesion using acoustic radiation force impulse (ARFI) technology. This retrospective study was conducted with the approval of the institutional review board. Shear wave velocity was measured using a linear array transducer with a bandwidth of 4-9 MHz and Virtual Touch tissue quantification (Siemens Medical Solutions, Mountain View, CA, USA) in 50 patients. First, the values of the shear wave velocity were determined in the normal tissues. Then, the changes in the shear wave velocity while applying external compression on the breast were determined. For the differential diagnosis of breast lesions, the shear wave velocities of 30 mass lesions (13 benign and 17 malignant lesions) classified as BI-RADS category 4 were measured. The mean shear wave velocities in the subcutaneous fat and the mammary gland parenchyma were 2.66 m/s and 3.03 m/s, respectively (p=0.0006). The mean shear wave velocity measured while applying external compression was 3.33 m/s for subcutaneous fat (p<0.0001), and 3.84 m/s for the mammary gland parenchyma (p<0.0001). In 4 of malignant cases, the shear wave velocity was not indicated (displayed as X.XX; unmeasurable state). The mean shear wave velocity of the 13 malignant lesions (4.49 m/s) was higher than that of benign lesions (2.68 m/s) (p<0.01). ARFI tissue quantification is thought to be a potentially promising ultrasound technique for the diagnosis of breast lesions, but further investigation is required to identify the most appropriate method of measurement.
    European journal of radiology 07/2011; 80(2):e182-7. DOI:10.1016/j.ejrad.2011.05.020 · 2.16 Impact Factor