A new approach to the detection of lesions in mammography using fuzzy clustering

Breast cancer is a leading cause of female mortality and its early detection is an important means of reducing this. The present study investigated an approach, based on fuzzy clustering, to detect small lesions, such as microcalcifications and other masses, that are hard to recognize in breast cancer screening. A total of 180 mammograms were analysed and classified by radiologists into three groups (n = 60 per group): those with microcalcifications; those with tumours; and those with no lesions. Twenty mammograms were taken as training data sets from each of the groups. The algorithm was then applied to the data not taken for training. Analysis by fuzzy clustering achieved a mean accuracy of 99.7% compared with the radiologists' findings. It was concluded that the fuzzy clustering algorithm allowed for more efficient and accurate detection of breast lesions and may improve the early detection of breast tumours.     

Metaplastic carcinoma of the breast: mammographic and sonographic findings

PURPOSE: We investigated the mammographic, sonographic, and pathologic findings in metaplastic carcinoma of the breast. METHODS: The mammographic (n = 16) and sonographic (n = 11) findings in 16 patients with metaplastic carcinoma of the breast were analyzed retrospectively along with pathologic findings. Whenever possible, results of preoperative fine-needle aspiration biopsy and immunohistochemical studies were obtained. RESULTS: All patients presented with a palpable breast mass. The mean size of the lesions at pathologic examination was 4.2 cm. On mammography, 15 patients had a mass (1 patient had 2 masses), and 1 patient had only clustered microcalcifications without an associated mass. The mean longest diameter of the 16 masses on mammography was 4.6 cm. Eleven lesions (69%) were round to ovoid in shape, 13 lesions (81%) showed ill-defined or obscured margins, and 10 lesions (63%) showed associated architectural distortion. On sonography, 6 (55%) of 11 lesions were round to ovoid, 9 lesions (82%) had well-defined margins, and 6 lesions (55%) showed complex echogenicity with solid and cystic components. At pathologic examination, 4 of these 6 lesions showed hemorrhagic or cystic necrosis. Axillary lymph nodes were positive in 6 (40%) of 15 patients in whom axillary node dissection was performed. CONCLUSIONS: Metaplastic carcinoma of the breast manifests as a rapidly growing, mammographically ill-defined round mass with associated architectural distortion on mammograms. Complex echogenicity with solid and cystic components may be seen sonographically and is related to hemorrhagic or cystic necrosis seen pathologically.     

Sonographic evaluation of mammographically detected microcalcifications without a mass prior to stereotactic core needle biopsy

PURPOSE: The purpose of this prospective study was to evaluate the clinical usefulness of sonographically re-evaluating areas of microcalcification found mammographically before undertaking stereotactic core needle biopsy (SCNB). METHODS: Patients with nonpalpable breast lesions appearing as microcalcifications on mammograms and who had been referred to us for SCNB were re-evaluated sonographically before the procedure. None of the breast lesions had been associated with a density on the mammograms, and the initial sonographic evaluations had been negative. Using the mammograms for correlation, we meticulously re-evaluated the areas of microcalcifications sonographically using a high-frequency linear-array transducer. The sonographic and histopathologic results were then reviewed and correlated. The sonographic findings and visibility of the mammographically detected microcalcifications were analyzed by the 2-tailed Fisher's exact test and the chi-square test. RESULTS: Sixty-six patients, who had 68 cases of microcalcifications, were enrolled. Thirteen of the 66 patients underwent surgery, and 9 of the 13 were found to have breast carcinoma. In the sonographic re-evaluation before SCNB in these 9 patients, an associated soft tissue mass was demonstrated in 5 patients but not in the other 4. Sonographic re-evaluation also revealed abnormalities in 24 of 68 cases (35.3%), in contrast to the negative findings on the initial sonography. Using the chi-square test to identify a trend, we found that the percentage of cases that were sonographically visible was highest for clustered benign microcalcifications and lowest for segmental benign microcalcifications (p < 0.0001). CONCLUSIONS: In breast lesions that appear as microcalcifications without an associated mass on mammograms, pre-SCNB sonographic re-evaluation with a high-frequency transducer can depict microcalcifications, particularly the clustered ones, and can detect small associated masses. Although the absence of a sonographically detectable mass in areas of mammographically detected microcalcifications does not guarantee the absence of cancer, the presence of an associated mass on sonography should warrant close follow-up in the case of negative results to avoid a delay in the diagnosis of breast carcinoma.     

Sonographic Findings of High‐Grade and Non–High‐Grade Ductal Carcinoma In Situ of the Breast

Objective. The purpose of this study was to differentiate between high‐grade and non–high‐grade ductal carcinoma in situ (DCIS) of the breast on sonography. Methods. From October 2003 to August 2009, 76 DCIS lesions in 73 women who underwent sonography and mammography were included in this study. Lesions were confirmed by mastectomy, breast‐conserving surgery, or surgical biopsy. Images were analyzed by 2 radiologists with consensus and were correlated with histologic grades. Results. Of the 76 lesions, 44 were classified as high‐‐grade and 32 as non–high‐grade DCIS. Fifty‐seven lesions (75.0%) were identified on sonography, which revealed a mass in 30 cases, microcalcifications in 20, ductal changes in 4, and architectural distortion in 3. All cases with false‐negative findings on sonography (n = 19) showed microcalcifications on mammography. On sonography, masses were more frequently found in non–high‐grade (62.5%) than high‐grade DCIS (22.7%; P < .01). No significant difference was seen in the sonographic features of masses between high‐grade and non–high‐grade DCIS. Microcalcifications were more common in high‐grade (43.2%) than non–high‐grade (3.1%) DCIS (P = .02). Most sonographically visible microcalcifications had associated findings such as ductal changes (n = 11), a mass (n = 7), or a hypoechoic area (n = 5). The detection rate of microcalcifications on sonography was higher in high‐grade (62.9%) than non–high‐grade DCIS (25.0%; P = .023). Conclusions. Microcalcifications with associated ductal changes (11 of 31 [35.5%]) were the most common sonographic findings in high‐grade DCIS. An irregular hypoechoic mass with an indistinct and microlobulated margin (13 of 26 [50.0%]) was the most frequent finding in non–high‐grade DCIS.     

Phantom-based comparison of conventional versus phase-contrast mammography for LCD soft-copy diagnosis

Purpose

Liquid crystal display (LCD) of mammograms provides soft-copy results that differ in conventional and phase contrast mammography (PCM). PCM potentially offers the highest quality of sharpness and graininess, an edge emphasis effect on the object, and the highest image resolution. However, when the image is displayed on an LCD, the resolution depends on the pixel pitch and the PCM image data must be diminished. We investigated the observed effect on spatial resolution and contrast when conventional or phase contrast mammograms are viewed on an LCD.

Methods

Using the tissue-equivalent phantom (Model 1011A), a conventional mammogram and a magnification radiography image were obtained with a PCM system. This phantom contains simulated fibers, microcalcifications, and masses. The PCM image was reduced 1/1.75 to render it consistent with life size mammography using the nearest neighbor, bilinear, and bicubic interpolation methods. The images were displayed on a five million (5M)-pixel LCD with 100 % magnification. Ten mammography technicians observed the reduction images displayed on LCDs and reported their results.

Results

In the detectability of the microcalcifications, there was no significant difference between conventional mammograms and reduced PCM images. Regarding fibers and masses, detectability using reduced images was higher than those of conventional images. The detectability using images reduced by the nearest-neighbor method was lower than those of images reduced by two other interpolation methods. Bilinear interpolation was affected by the smoothing effect, while CNR was increased. In addition, since the noise of PCM image was reduced by an air gap effect, high detectability of key image features was found.

Conclusions

Soft-copy display of phase-contrast mammograms is feasible with LCDs, while detectability of fibers and masses was best with bilinear interpolation and use of an air gap.     

数字化乳腺X线引导下钙化导丝定位切除活检病例的影像与病理的相关性分析

目的 回顾性分析数字化乳腺X线引导下钙化导丝定位切除活检证实的良恶性病例之间X线征象差异性,筛选乳腺良恶性微钙化鉴别的有效客观性影像学因子,分析导丝定位存在的问题,为获得更客观地活检指征、降低乳腺微钙化过度活检提供依据。材料与方法收集2009-7至2011-3年数字化乳腺X线引导下钙化导丝定位切除活检病例。阅片者在不知道钙化良恶性结果的情况下阅读X线图像,记录病变X线征象（钙化类型、分布类型、分布范围、背景腺体密度、BI-RADS）。比较良恶性微钙化的X线征象差异性,分析各乳腺X线征象对良恶性微钙化鉴别的意义。比较BI-RADS 4A、4B、4C组间良恶性微钙化的分布差异。结果 入组共98例,良性72例（73.5%）,恶性26例（26.5%）。经过分析,病变良恶性与钙化类型、BI-RADS分级相关,与年龄、钙化分布、分布范围及腺体密度无显著相关。BI-RADS 4级亚级间良恶性病变分布存在差异（P=0.003）,BI-RADS 4C的恶性病变所占比例最高（72.7%）,BI-RADS 4A的良性病例所占比例最高（84.6%）。结论 乳腺X线引导下导丝定位切除活检能够有效地发现乳腺癌,但尽量避免过度活检。钙化类型和BI-RADS是恶性乳腺钙化的有效影响因子。     

Ultrasonographic features of focal xanthogranulomatous pyelonephritis.

OBJECTIVE: To analyze the ultrasonographic features of focal xanthogranulomatous pyelonephritis. METHODS: Ultrasonographic features of 15 patients with pathologically proved focal xanthogranulomatous pyelonephritis were retrospectively analyzed by 2 radiologists who reached a consensus, in terms of the location, margin, size, and echo texture of the mass, associated calculi, lymphadenopathy, or local extension, in comparison with computed tomographic and clinical findings. RESULTS: At ultrasonography, 12 (80%) of 15 masses were well circumscribed. The maximal sizes of the masses ranged from 2.5 to 5.8 (mean, 3.8) cm. Thirteen solid masses (87%) were hyperechoic (n = 7), hypoechoic (n = 4), or isoechoic (n = 4) to the renal cortex, and the preoperative diagnosis was either renal cell carcinoma (n = 11) or Wilms tumor (n = 2). The preoperative diagnosis of the other 2 cystic lesions (13%) was renal abscess. Renal calculi were found in 1 case, but lymphadenopathy or local extension was not depicted. Clinical inflammatory signs were found in 11 of 15 patients. CONCLUSIONS: There were no specific ultrasonographic features that allow for the distinction between focal xanthogranulomatous pyelonephritis and renal tumors or abscesses. Focal xanthogranulomatous pyelonephritis should be considered when there are clinical signs of infection or inflammation and a focal solid mass is seen on ultrasonography.     

Sonographic appearance of ductal carcinoma in situ diagnosed with ultrasonographically guided large core needle biopsy: correlation with mammographic and pathologic findings.

The purpose of this study was to evaluate sonographic features of ductal carcinoma in situ diagnosed percutaneously at ultrasonographically guided large core needle biopsy. Of 619 biopsies, 203 breast carcinomas were diagnosed, of which nine were pure ductal carcinoma in situ. All ductal carcinoma in situ lesions appeared sonographically as hypoechoic masses without a pseudocapsule. Grade 1 lesions (n = 2; mean size, 9.5 mm), grade 2 lesions (n = 4; mean size, 18 mm) and grade 3 lesions (n = 3; mean size, 32 mm) had means of 0, 1, and 5 malignant sonographic features, respectively. Ductal carcinoma in situ appeared mammographically as a mass, with two of four grade 2 lesions and all grade 3 lesions demonstrating suspicious microcalcifications. One grade 3 ductal carcinoma in situ was spiculated. In conclusion, ductal carcinoma in situ lesions tended to show more malignant mammographic and sonographic features as histologic grade and size increased.     

MRI to X-ray mammography registration using a volume-preserving affine transformation

X-ray mammography is routinely used in national screening programmes and as a clinical diagnostic tool. Magnetic Resonance Imaging (MRI) is commonly used as a complementary modality, providing functional information about the breast and a 3D image that can overcome ambiguities caused by the superimposition of fibro-glandular structures associated with X-ray imaging. Relating findings between these modalities is a challenging task however, due to the different imaging processes involved and the large deformation that the breast undergoes. In this work we present a registration method to determine spatial correspondence between pairs of MR and X-ray images of the breast, that is targeted for clinical use. We propose a generic registration framework which incorporates a volume-preserving affine transformation model and validate its performance using routinely acquired clinical data. Experiments on simulated mammograms from 8 volunteers produced a mean registration error of 3.8±1.6mm for a mean of 12 manually identified landmarks per volume. When validated using 57 lesions identified on routine clinical CC and MLO mammograms (n=113 registration tasks) from 49 subjects the median registration error was 13.1mm. When applied to the registration of an MR image to CC and MLO mammograms of a patient with a localisation clip, the mean error was 8.9mm. The results indicate that an intensity based registration algorithm, using a relatively simple transformation model, can provide radiologists with a clinically useful tool for breast cancer diagnosis.     

BI-RADS词典钙化描述语的应用价值分析

目的：依据乳腺影像报告和数据系统（breast imaging-report and data system,BI-RADS）词典中的钙化描述语,回顾性分析数字钼靶摄影中钙化病灶的恶性度。方法收集126例可疑恶性钙化的病例,由2位影像科医生对数字钼靶摄影中的钙化进行分析,从形态和分布两方面进行描述语记录,之后与术后病理结果对照,分析BI-RADS钙化描述语对恶性度的预测价值。结果126例病例中,恶性61例。形态描述语中,恶性度最高的是细线或细线分支状（93%）;分布描述语中：恶性度最高的是段样（75%）。结论 BI-RADS词典中,钙化描述语能够帮助评估数字钼靶摄影中钙化病灶的恶性度。     

Differential diagnosis of focal epididymal lesions with gray scale sonographic, color Doppler sonographic, and clinical features.

OBJECTIVE: To determine whether focal epididymal lesions can be differentiated on gray scale sonographic, color Doppler sonographic, and clinical features. METHODS: This was a retrospectiveanalysis of 60 focal epididymal lesions in 57 patients. Focal epididymal lesions were classified into 3 groups: nonspecific epididymitis (n = 43), tuberculous epididymitis (n = 10), and benign epididymal masses (n = 7). The following gray scale sonographic, color Doppler sonographic, and clinical features were analyzed: size, location, echogenicity, and heterogeneity of the lesion; hypoechoic or hyperechoic rim presence; hydrocele presence; degree of blood flow in the lesion; patient's age; duration of symptoms; and scrotal tenderness. RESULTS: Lesions were larger in patients with tuberculous epididymitis than in those with either nonspecific epididymitis (P = .007) or benign epididymal masses (P = .0017). The hypoechoic or hyperechoic rim of the lesion was more common in patients with benign epididymal masses than in those with nonspecific epididymitis (P = .002). The degree of blood flow in the lesion was greater in patients with nonspecific epididymitis than in those with either tuberculous epididymitis (P = .0019) or benign epididymal masses (P < .001). The duration of symptoms was shorter in patients with nonspecific epididymitis than in those with either tuberculous epididymitis (P < .001) or benign epididymal masses (P = .0092). The frequency of scrotal tenderness was higher in patients with nonspecific epididymitis than in those with either tuberculous epididymitis (P < .001) or benign epididymal masses (P < .001). CONCLUSIONS: Gray scale sonographic, color Doppler sonographic, and some clinical features may be helpful for differential diagnosis of focal epididymal lesions.     

磁共振扩散加权成像对肝脏常见肿瘤的诊断及鉴别诊断作用

目的：探讨磁共振扩散加权成像对肝脏常见肿瘤的诊断及鉴别诊断的作用。方法：选取肝脏常见肿瘤88例，其中原发性肝癌28例，肝转移瘤15例，肝血管瘤33例，肝囊肿12例。行轴位扩散加权扫描，并拟合出ADC图，在ADC图上测出ADC值并进行统计分析。然后行动态增强全肝扫描，观察实性病变在动脉期、门脉期以及延迟期不同时相的强化程度。结果：肝囊肿和血管瘤ADC值均明显高于原发性肝癌、转移瘤（P＜0.01），根据多期动态增强扫描动脉期肝脏恶性肿瘤病灶的表现将其分为富血供病灶和乏血供病灶。结论：ADC值的应用大大提高了MRI对肝脏常见肿瘤的诊断和鉴别诊断能力。     

几何模型匹配乳腺头足位与内外斜位X线片所示病灶

目的 观察几何模型(GM)匹配乳腺头足(CC)位与内外斜(MLO)位X线片所示病灶的价值。方法 回顾性分析493例接受乳腺CC位和MLO位X线摄影的乳腺病灶患者,共598个乳腺病灶,包括499个钙化灶和99个肿块。构建GM用于匹配CC与MLO位片所示乳腺病灶,再以环形法(AB)和直线法(SS)进行对比,分别计算匹配误差,包括GM匹配误差、AB径向误差及SS轴向误差;分析GM对CC及MLO位图像中同一病灶的匹配性能,评价其应用价值。结果 GM对乳腺钙化灶和肿块的匹配误差分别为2.85(1.45,5.08)及3.70(1.35,6.25)mm,差异无统计学意义(Z=-1.344,P=0.179)。对乳腺上部病灶,AB匹配的径向误差和SS匹配的轴向误差均大于下部病灶(P均<0.001);对乳腺外侧病灶,AB的径向误差和SS的轴向误差均大于内侧病灶(P均<0.05)。GM、AB及SS间匹配误差整体差异有统计学意义(H=93.012,P<0.001);两两比较差异均有统计学意义(P均<0.05),GM匹配性能明显优于AB和SS。GM匹配误差与摄片时乳腺压迫厚度无明显相关性...     

Raman spectroscopy: a real-time tool for identifying microcalcifications during stereotactic breast core needle biopsies

Microcalcifications are an early mammographic sign of breast cancer and a target for stereotactic breast needle biopsy. We present here a Raman spectroscopic tool for detecting microcalcifications in breast tissue based on their chemical composition. We collected ex vivo Raman spectra from 159 tissue sites in fresh stereotactic breast needle biopsies from 33 patients, including 54 normal sites, 75 lesions with microcalcifications and 30 lesions without microcalcifications. Application of our Raman technique resulted in a positive predictive value of 97% for detecting microcalcifications. This study shows that Raman spectroscopy has the potential to detect microcalcifications during stereotactic breast core biopsies and provide real-time feedback to radiologists, thus reducing non-diagnostic and false negative biopsies.     

全数字化乳腺X线摄影在乳腺癌诊断中的作用

目的分析经手术病理证实的乳腺病变在全数字化乳腺摄影（FFDM）中的影像学表现,提高X线在乳腺癌诊断中的准确性。方法搜集2008年1月-2010年10月313例行FFDM检查、手术和病理证实的乳腺病变患者的临床资料及乳腺X线片,由放射科医师对患者的X线片观察并分析,参照乳腺影像学报告和数据系统（BI-RADS）进行分级,以术后病理结果为金标准,评价FFDM检查诊断乳腺癌的灵敏度、特异度、准确率、阳性预测值和阴性预测值,并分析误诊和漏诊的原因。结果病理结果显示,313例乳腺标本中,乳腺癌194例,乳腺良性病变119例。在乳腺恶性病变中,X线主要表现为单纯肿块型83例,钙化型95例,结构扭曲6例,不对称致密影8例,乳腺内弥漫性腺体结构模糊2例。X线诊断假阳性18例,假阴性20例。FFDM检查对乳腺癌诊断的灵敏度、特异度、准确率、阳性预测值、阴性预测值分别约89.2%、84.9%、87.7%、90.6%、82.8%。误诊的主要原因是肿块的边缘形态、微小钙化等类似于恶性;漏诊的主要原因是乳腺腺体致密、不对称致密影及微小结构扭曲。结论数字化乳腺X线摄影在乳腺癌诊断中具有较高的价值。     

Intraoperative sonographic localization of breast masses: success with specimen sonography and surgical bed sonography to confirm excision.

OBJECTIVE: To assess the use of intraoperative sonography for localization of breast masses at excisional biopsy, with specimen and surgical bed sonography to confirm excision. METHODS: A computer search of the 5-year period from January 1993 through January 1998 revealed 138 consecutive women referred for sonographically guided excisional biopsy of 148 masses; 35 masses were excluded because they had no postoperative mammograms. One hundred thirteen masses constituted the study group. Specimen sonography (n = 60) or surgical bed sonography (n = 53) was performed as the initial evaluation to confirm excision, but ultimately, surgical bed sonography may have been necessary after specimen sonography, and specimen sonography may have been necessary after surgical bed sonography. The miss rates determined by postoperative imaging were calculated for each group and compared with those of mammographically guided needle localization series from the literature. RESULTS: Follow-up physical examination and mammography showed no residual mass in the region of surgery in any patient. However, follow-up sonography had 1 miss in the initial specimen sonogram group (1 [1.7%] of 60) and 1 miss in the initial surgical bed group (1 [1.9%] of 53). As shown by the Fisher exact test, there was no significant difference between the miss rates of the 2 initial methods of confirming lesion excision or between the miss rates of these initial methods, both groups combined, and 6 mammographic localization series from the literature. CONCLUSION: Intraoperative breast sonography, using specimen sonography and scanning the surgical bed, has miss rates comparable with those of mammographic needle localization. Follow-up sonography must be performed if there is any doubt of complete excision.     

Do Medicare patients with disabilities receive preventive services? A population-based study.

OBJECTIVE: To compare health maintenance procedure rates of Medicare patients with different levels of disability. STUDY DESIGN: Observational study analyzing data from the 1995 Medicare Current Beneficiary Survey (MCBS, n = 15,590). Self-reported Pap smears, mammograms, and influenza and pneumococcal vaccinations were compared between groups with different levels of health-related difficulties in six activities of daily living (ADL). RESULTS: Compared to those without disabilities, the most severely disabled women (limitations in 5 or 6 ADL) reported fewer Pap smears (age < or =70, 23% vs 41%, p < .001) and mammograms (age > or = 50, 13% vs 44%, p < .001). In a controlled analysis, individuals with this high level of disability were 57% (95% confidence interval [CI], 33% to 72%) and 56% (95% CI, 43% to 76%) less likely to report receiving Pap smears and mammograms, respectively, compared with able-bodied women, regardless of their age, whether they were in an HMO, or whether they lived in a long-term care facility. Functional limitations were not a deterrent to receiving vaccinations. In general, patients in HMOs reported more procedures than those in fee-for-service, while those in long-term care facilities reported fewer procedures than those living in the community. CONCLUSIONS: Disability among Medicare patients is a significant, independent risk factor for not receiving mammograms and Pap smears. Efforts should be made to identify the most severely disabled because they are at particular risk.     

数字化乳腺X线摄影检出BI-RADS 3~5级微钙化病变的动态增强MR研究

目的探讨DCE-MRI对数字化乳腺X线摄影检出BI-RADS3-5级微钙化病变的诊断价值。方法44例数字化乳腺X线摄影发现BI-RADS3-5级微钙化的患者于活检前完成双乳DCE-MR检查,以术后病理诊断为金标准,分析BI-RADS3～5级微钙化病变的DCE-MRI特点。结果病理证实良性微钙化病变13例,恶性微钙化病变31例。38.46%(5/13)良性单纯微钙化病变在DCE-MRI上无强化,93.33%(14/15)恶性微钙化伴肿块或局限性致密影病变在DCE-MRI上有明显强化,良恶性微钙化病变在DCE-MRI上早期增强率之间差异有显著统计学意义。DCE-MRI对微钙化病变诊断的敏感性和特异性分别为96.77%和92.31%。结论良恶性微钙化病变的DCE-MRI表现有明显差异,DCE-MRI有助于微钙化病变的定性诊断。     

卵巢肿块的CT诊断

目的探讨卵巢肿块的CT表现和诊断价值。方法回顾性分析96例卵巢肿块的临床及CT表现,患者年龄15岁～80 岁,平均47岁。CT检查包括平扫和增强扫描,层厚、层隔5mm-10mm,通常范围为耻骨联合下缘至髂前上棘,肿块巨大者上界应完全覆盖病灶。扫描前夜起分次口服1％-2％泛影葡胺水溶液,总量约1500ml,以充分充盈盆腔肠管,已婚妇女扫描前常规使用阴道塞。本组病例均经手术病理证实。结果在96例患者中共检出108个病灶,手术病理报告畸胎瘤22例(22个病灶),囊腺瘤14例(14个病灶),卵巢囊肿20例(24个病灶),囊腺癌32例(36个病灶),转移癌4例(8个病灶),其它病变4例(4个病灶)。结论 CT发现病变的敏感性100％,定性诊断准确率87％。     

Radiologic findings of lobular carcinoma in situ: mammography and ultrasonography

Purpose. The purpose was to evaluate the mammographic and sonographic (US) features of lobular carcinoma in situ (LCIS). Methods. Mammographic and US findings of nine lesions diagnosed pathologically as pure LCIS were analyzed retrospectively according to the American College of Radiology breast imaging reporting and data system (BI‐RADS) lexicon. Results. With regards to mammographic findings of LCIS, there were no lesions demonstrated in six cases and a mass in three cases, two of which contained microcalcifications. The most common US findings of LCIS were irregular shape (five cases), ill‐defined margins (eight cases), and hypoechogenicity (seven cases). All cases had an elongated shape parallel to the skin or were round (no lesion had a taller‐than‐wide shape). Two cases were associated with microcalcifications. The final BI‐RADS categories were category 3 (probably benign finding) in one case, category 4A (low suspicion of malignancy) in two cases, and category 4B (intermediate suspicion of malignancy) in six cases. Conclusions. LCIS is frequently mammographically occult, and an incidental finding on routine screening mammograms, usually because of microcalcifications. LCIS, a high‐risk lesion, can mimic invasive carcinoma on US. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound, 2010