Digital mammography: observer performance study of the effects of pixel size on the characterization of malignant and benign microcalcifications.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the effects of pixel size on the characterization of mammographic microcalcifications by radiologists. MATERIALS AND METHODS: Two-view mammograms of 112 microcalcification clusters were digitized with a laser scanner at a pixel size of 35 microm. Images with pixel sizes of 70, 105, and 140 microm were derived from the 35-microm-pixel size images by averaging neighboring pixels. The malignancy or benignity of the microcalcifications had been determined with findings at biopsy or 2-year follow-up. Region-of-interest images containing the microcalcifications were printed with a laser imager. Seven radiologists participated in a receiver operating characteristic (ROC) study to estimate the likelihood of malignancy. The classification accuracy was quantified with the area under the ROC curve (Az). The statistical significance of the differences in the Az values for different pixel sizes was estimated with the Dorfman-Berbaum-Metz method and the Student paired t test. The variance components were analyzed with a bootstrap method. RESULTS: The higher-resolution images did not result in better classification; the average Az with a pixel size of 35 microm was lower than that with pixel sizes of 70 and 105 microm. The differences in Az between different pixel sizes did not achieve statistical significance. CONCLUSION: Pixel sizes in the range studied do not have a strong effect on radiologists' accuracy in the characterization of microcalcifications. The low specificity of the image features of microcalcifications and the large interobserver and intraobserver variabilities may have prevented small advantages in image resolution from being observed.

Mammographic appearance of breast cancer in African-American women: report of 100 consecutive cases.

RATIONALE AND OBJECTIVES: The authors determined the mammographic appearance of breast carcinoma in African-American women and compared it with that in a white cohort. MATERIALS AND METHODS: The authors reviewed the mammograms, clinical records, and pathology records of 97 consecutive African-American women with 100 confirmed breast cancers and 110 white women with 111 confirmed breast cancers. RESULTS: The mammograms obtained in African-American women were positive in 94 cases (94%), and those obtained in white women were positive in 99 cases (89%). Forty-seven percent of malignancies in African-American women appeared as calcifications, alone or with a mass, and 41% appeared as a mass only. There was no statistically significant difference in the frequency of these two findings between the African-American and the white populations. There was no statistically significant difference in the breast parenchymal pattern between the two groups. The most common tumor location in both races was the upper outer quadrant. CONCLUSION: Breast carcinoma in African-American women is similar to that in white women in terms of mammographic appearance, location, and breast density. The mammographic appearance should not be an impediment to the detection of breast cancer in African-American women.

Locally advanced breast carcinoma: accuracy of mammography versus clinical examination in the prediction of residual disease after chemotherapy.

PURPOSE: To determine the mammographic features of locally advanced breast carcinoma treated with neoadjuvant chemotherapy and to evaluate the accuracy of mammography in the prediction of residual carcinoma. MATERIALS AND METHODS: Of 90 women treated with hormonally synchronized cytotoxic therapy before mastectomy or lumpectomy for advanced breast carcinoma, 56 were selected because they had undergone mammography before and after neo-adjuvant therapy. Mammographic and clinical opinion on the presence of residual disease was compared with histologic results. RESULTS: Fifty-four (96%) of 56 women had a complete (n = 34 [61%]) or partial (n = 20 [36%]) clinical response. Thirteen (23%) of 56 women had no residual tumor. Sensitivity of mammography in the prediction of residual carcinoma was greater than that of clinical examination (79% vs 49%), but specificity was lower (77% vs 92%). In 24 women with inflammatory carcinoma, sensitivity of mammography was 78% while that of clinical examination was 39%; specificity was equal (83%). CONCLUSION: Mammography was more sensitive than clinical examination in the prediction of residual carcinoma; it was not accurate enough to obviate surgical biopsy.

Mammographic appearance of cancer in the opposite breast: comparison with the first cancer.

OBJECTIVE: Patients who have had cancer in one breast are at high risk for cancer in the contralateral breast. These bilateral cancers may be synchronous or metachronous. If the manifestations on mammography were similar in both breasts, an aggressive search for the mammographic findings of the first breast cancer might lead to early detection of the contralateral cancer. The purpose of this study was to evaluate mammograms for patients with bilateral cancers to determine whether the mammographic appearance of the contralateral cancer is likely to be the same as that of the first cancer. MATERIALS AND METHODS: We retrospectively reviewed the pathologic and mammographic records of 69 patients with surgically proven bilateral primary breast cancer. Thirty four of 69 (49%) had synchronous cancer, and 35 (51%) had metachronous cancer. Mammographic appearances were classified as microcalcifications, spiculated mass, nonspiculated mass (whether circumscribed or poorly defined), asymmetric or developing density, architectural distortion, and normal. Multiple findings were subclassified as major and minor findings. All findings were compared between both breast cancers, and statistical significance was determined by the two-sample Z test. RESULTS: Forty six (67%) of 69 patients had different major mammographic findings in the contralateral cancer. Of 30 patients whose first cancers had microcalcifications, 20 (67%) had microcalcifications in the contralateral cancer. Of 39 patients whose first cancers lacked microcalcifications, 17 (44%) had microcalcifications in the contralateral cancer. This difference was statistically significant (p = .02). Of 26 patients whose first cancers had spiculated masses, 9 (35%) had a contralateral spiculated mass. Of 43 patients whose first cancers lacked spiculated masses, 12 (28%) had a contralateral spiculated mass. This difference was not statistically significant (p = .22). CONCLUSION: Our results show that contralateral tumors usually have major mammographic findings different from those of the first cancer, and the mammographic signs of the first cancer do not indicate the most likely appearance of cancer in the contralateral breast. Evaluation of a contralateral mammogram should be performed without regard for the mammographic findings for the first cancer.

Hepatic artery resistance before and after standard meal in subjects with diseased and healthy livers.

PURPOSE: To assess fasting and postprandial resistive index (RI) in subjects with healthy and diseased livers. MATERIALS AND METHODS: Subjects with healthy (n = 10) and diseased (n = 33) livers underwent fasting and postprandial Doppler ultrasonography of the hepatic artery. Findings were compared with parameters for liver disease and Child class A-C and Child score of 5-15. RESULTS: The mean postprandial RI increase in healthy subjects was 42% (all, > or = 20%) and in patients with liver disease was 7% (six, > or = 20%). Patients with class A disease (n = 12) had a significantly greater increase in post-prandial RI (13%) than those with class B or C disease (3%) (P < .05). All patients with class C disease (n = 9) had an increased postprandial RI of less than 10%. The 13 patients with at least 10% increase in postprandial RI had less severe liver disease (Child score, 6.1 +/- 1.3 [standard deviation]) than the 20 patients with less than 10% increase (Child score, 8.4 +/- 1.7) (P < .01). CONCLUSION: A normal marked increase in postprandial RI is generally not seen in patients with severe liver disease.

Pure and mixed mucinous carcinoma of the breast: pathologic basis for differences in mammographic appearance.

OBJECTIVE: It is important to differentiate pure and mixed mucinous carcinomas of the breast because the former have a more favorable prognosis. We correlate histopathologic findings with mammographic findings for 20 patients with pure or mixed mucinous carcinomas to determine differential characteristics and their pathologic basis. MATERIALS AND METHODS: We searched our pathology database of 2219 consecutive women with a diagnosis of breast cancer and found that 31 (1.4%) had mucinous carcinomas. Eleven women were excluded because the mammograms (n = 6) or the microscopic slides (n = 5) were not available. The remaining 20 women, who were 37-92 years old (mean, 64 years), were the subjects of the study. Their clinical records, mammograms, and microscopic slides were reviewed. Tumor size was based on the maximum mammographic diameter or measured diameter of the excised tumor. RESULTS: Seventeen patients (85%) had tumors that were mammographically apparent. Histopathologic review confirmed 15 pure mucinous tumors and five mixed mucinous tumors having an overall mean diameter of 3.4 cm. The pure-tumor group contained three incidentally detected tumors (all < or = 0.8 cm in diameter); six that had a circumscribed, lobular contour on mammograms (mean diameter, 3.6 cm); and six that had a poorly defined, irregular contour (mean diameter, 1.2 cm). One of the mammographically apparent small pure tumors contained histologically confirmed psammomatous microcalcifications. All pure tumors had microscopically evident circumscribed margins that could have accounted for the circumscribed mammographic appearance of the larger masses. All mixed tumors had mammographically and histologically evident irregular margins because of the associated fibrosis and infiltrative margins of the nonmucinous component (mean diameter, 5.3 cm). CONCLUSION: There are differences in the mammographic appearances of pure and mixed mucinous carcinomas that have a histopathologic basis. Circumscribed, lobular margins on mammograms are characteristic of large pure tumors and are the result of their microscopically evident circumscribed margins and expansile growth pattern. Irregular margins on mammograms are more characteristic of mixed mucinous tumors, regardless of tumor size, and are attributable to the fibrotic and infiltrative nature of the nonmucinous component.

Transmastoid labyrinthectomy: reliable surgical management of vertigo.

Transmastoid labyrinthectomy has continued to be an important part of the surgical armamentarium for patients with vertigo and nonserviceable hearing loss. Continuing experience substantiates our earlier impression that the vestibular system usually accommodates rapidly to complete unilateral surgical ablation, regardless of age or degree of residual vestibular activity in the ear (as measured by preoperative bithermal caloric testing). Although the symptom of vertigo is reliably treated by transmastoid labyrinthectomy, a patient questionnaire has demonstrated a significant incidence of mild to moderate persisting postoperative dysequilibrium. Although this dysequilibrium is usually not debilitating, this questionnaire has demonstrated its existence more precisely than a retrospective review of the patients' clinical records. This study reviews 110 patients who underwent labyrinthectomy between 1978 and 1985. We remain impressed at the efficacy of the transmastoid labyrinthectomy in relieving the symptom of vertigo.

In vivo stochastic ultrasonic characterisation of abdominal tissues.

Two experimental systems have been used for digitization of waveforms backscattered from normal and pathologic abdominal tissues in vivo. Initial studies were performed with a digitization system which allowed only A-mode display of areas of interest before and during waveform recording. A new interactive system allows for digitization of waveforms from areas of interest in abdominal organs, selected with the aid of real-time B-mode images of a mechanical sector scanner. Statistical parameters of these waveforms, derived in the amplitude and frequency domains, show potential utility for diagnosis of diffuse diseases of the liver and spleen.

In vivo ultrasonic tissue characterization of human intracardiac masses.

Interactions between an ultrasonic signal and cardiac tissue have been used to characterize the histologic state of myocardium in vitro. To assess the utility of in vivo ultrasonic tissue characterization, stochastic analysis was applied to the digitized echocardiographic signals from 15 patients with 2-dimensional echocardiograms suggesting intracardiac masses. Ten subjects with echocardiograms suggesting mural thrombi underwent subsequent surgery or necropsy, which confirmed thrombi in 6 and revealed no thrombi (designated artifact) in 4. Five other patients had intracardiac tumors. The amplitudes within the digitized ultrasonic signals were displayed as histograms, which were described by a parameter k that represented the degree to which each histogram departed from a totally random probability density function. In 5 of 6 thrombi, k = 0, but in all 4 artifacts, k greater than 0. The sixth thrombus had k = 0.5 due to the specular effect of the interface between the thrombus' 2 lobes. All 5 tumors had k greater than 0. Ultrasonic tissue characterization using a stochastic analysis of backscatter can be performed in vivo and helps differentiate thrombus from artifact and tumor in the heart.

Stochastic frequency-domain tissue characterization: application to human spleens "in vivo'.

Ultrasonic waveforms backscattered from normal and pathologic human spleens were recorded in vivo using a high-speed digital data acquisition system. A frequency-domain analysis was performed for 50 digitized waveforms from each spleen, in which autocorrelations of frequency spectra were employed to measure the mean spacing among adjacent tissue scatterers. Mean scatterer spacing for normal spleens averaged 1.10 +/- 0.14 mm, whereas abnormal, diffusely of these measurements are in accord with those expected from splenic histology. The techniques described may be valuable in ultrasonic diagnosis of the spleen and other organs.

Ultrasonic characterization of abdominal tissues via digital analysis of backscattered waveforms.

Ultrasonic waveforms backscattered from normal and abnormal livers and spleens were recorded in vivo with the aid of a high-speed data acquisition system. Frequency-domain analysis of the digitized waveforms was employed to derive values for mean spacing of ultrasonic scatterers in tissue. Amplitude-domain analysis yielded measures of mean amplitude and variance, an indication of the distribution of amplitude values. Studies indicated that cirrhotic liver is characterized by a higher mean amplitude, a broader amplitude distribution, and a larger mean scatterer spacing than normal liver. Amplitude- and frequency-domain statistics for livers with other diffuse disease processes or tumor, as well for abnormal spleens. also differed from those of normal tissues. These data give information which may not be evident from B-mode sonograms, and which appears to be related to histological features.