Automatic segmentation of breast lesions on ultrasound

In this paper we present a computationally efficient segmentation algorithm for breast masses on sonography that is based on maximizing a utility function over partition margins defined through gray-value thresholding of a preprocessed image. The performance of the segmentation algorithm is evaluated on a database of 400 cases in two ways. Of the 400 cases, 124 were complex cysts, 182 were benign solid lesions, and 94 were malignant lesions. In the first evaluation, the computer-delineated margins were compared to manually delineated margins. At an overlap threshold of 0.40, the segmentation algorithm correctly delineated 94% of the lesions. In the second evaluation, the performance of our computer-aided diagnosis method on the computer-delineated margins was compared to the performance of our method on the manually delineated margins. Round robin evaluation yielded Az values of 0.90 and 0.87 on the manually delineated margins and the computer-delineated margins, respectively, in the task of distinguishing between malignant and nonmalignant lesions.

Providing professional mammography services: financial analysis

PURPOSE

To perform a financial analysis of mammography services to determine whether the key underlying economic drivers of this service are aligned with the public's expectations.

MATERIALS AND METHODS

The financial status of mammography services at seven university-based programs was assessed by using an extensive financial survey encompassing revenue, direct and indirect costs, and volume data for 1997 and 1998. At one of the institutions, an activity-based costing analysis was performed by procedure type: screening mammography, diagnostic mammography, breast ultrasonography, interventional procedures, and review of outside mammograms.

RESULTS

All seven institutions incurred losses in the professional component of mammography services. The underlying financial problem was a negative contribution margin (total mammography revenues minus direct expenses). The driver of the financial loss was the volume of diagnostic mammograms, which generated a loss per procedure. Diagnostic mammogram volume drove the mammography full-time equivalent count (P =.039) and was highly and negatively correlated with contribution margin (P <.001).

CONCLUSION

The reimbursement rate for mammography procedures, especially diagnostic mammography, needs to be increased to reflect the current reality of the resources necessary to maintain the accessibility and accuracy of this evolving mix of clinical services.

Rates and causes of disagreement in interpretation of full-field digital mammography and film-screen mammography in a diagnostic setting

OBJECTIVE

This study was performed to determine the rates and causes of disagreements in interpretation between full-field digital mammography and film-screen mammography in a diagnostic setting.

SUBJECTS AND METHODS

Patients undergoing diagnostic mammography were invited to participate in the digital mammography study. Three views, selected by the radiologist interpreting the film-screen mammography, were obtained in both film-screen mammography and digital mammography. Radiologists independently assigned a Breast Imaging Reporting and Data System (BI-RADS) category to the film-screen mammography and the digital mammography images. The BI-RADS categories were grouped into the general categories of agreement, partial agreement, or disagreement. A third and different radiologist reviewed all cases of disagreement, reached a decision as to management, and determined the primary cause of disagreement.

RESULTS

Six radiologists reviewed digital mammography and film-screen mammography diagnostic images in a total of 1147 breasts in 692 patients. Agreement between digital mammography and final film-screen mammography assessment was present in 937 breasts (82%), partial agreement in 159 (14%), and disagreement in 51 (4%), for a kappa value of 0.29. The primary causes of disagreement were differences in management approach of the radiologists (52%), information derived from sonography or additional film-screen mammograms (34%), and technical differences between the two mammographic techniques (10%).

CONCLUSION

Significant disagreement between film-screen mammography and digital mammography affecting follow-up management was present in only 4% of breasts. The most frequent cause of disagreement in interpretation was a difference in management approach between radiologists (interobserver variability). This source of variability was larger than that due to differences in lesion visibility between film-screen mammography and digital mammography.

Measuring satisfaction with mammography results reporting

OBJECTIVE

To assess factors associated with patient satisfaction with communication of mammography results and their understanding and ability to recall these results.

DESIGN

Cross-sectional telephone survey.

SETTING

Academic breast imaging center.

PATIENTS

Two hundred ninety-eight patients who had either a screening or diagnostic mammogram.

MEASUREMENTS AND MAIN RESULTS

Survey items assessed waiting time for results, anxiety about results, satisfaction with several components of results reporting, and patients' understanding of results and recommendations. Women undergoing screening exams were more likely to be dissatisfied with the way the results were communicated than those who underwent diagnostic exams and received immediate results (20% vs 11%, P =.05). For these screening patients, waiting for more than two weeks for notification of results, difficulty getting in touch with someone to answer questions, low ratings of how clearly results were explained, and considerable or extreme anxiety about the results were all independently associated with dissatisfaction with the way the results were reported, while age and actual exam result were not.

CONCLUSIONS

Patients undergoing screening mammograms were more likely to be dissatisfied with the way the results were communicated than were those who underwent diagnostic mammograms. Interventions to reduce the wait time for results, reduce patients' anxiety, and improve the clarity with which the results and recommendations are given may help improve overall satisfaction with mammography result reporting.

Management of complex breast cysts

OBJECTIVE

This study was undertaken to evaluate the various strategies currently in use to manage complex cysts and specifically address the need for intervention.

MATERIALS AND METHODS

A review of 4562 breast sonograms obtained during an 18-month period revealed 308 complex cysts in 252 women. Data collected from review of patient records included the patient's age and risk factors for breast cancer, aspiration or biopsy results (or both), follow-up imaging studies, and management recommendations.

RESULTS

Management recommendations for complex cysts were 1-year follow-up in 13 patients, 6-month follow-up in 148, sonographically guided aspiration in 82, aspiration with possible core biopsy in 62, and excisional biopsy in three. No malignancies were diagnosed in the group treated with follow-up imaging, sonographically guided aspiration, or excisional biopsy. One malignancy, a papilloma with a 3-mm focus of ductal carcinoma in situ, was diagnosed in one of the patients who underwent core biopsy.

CONCLUSION

Of the lesions classified as complex cysts, the malignancy rate was 0.3% (1/308). This malignancy rate is lower than that for lesions classified as probably benign using mammographic criteria (i.e., for lesions classified as category 3 lesions using the Breast Imaging Reporting and Data System). Because the accepted standard practice for management of probably benign lesions is follow-up studies, the low yield of malignancy in this series suggests that complex cysts can be managed with follow-up imaging studies instead of intervention.

Are malignant cells displaced by large-gauge needle core biopsy of the breast?

OBJECTIVE

The purpose of this paper is to determine the rate of tumor displacement resulting from large-gauge needle core biopsy in patients with breast carcinoma.

MATERIALS AND METHODS

Three hundred fifty-two cancer excisions in patients who had undergone large-gauge needle core biopsy were evaluated for evidence of tumor displacement. Three needle procedures were compared: vacuum-assisted, automated gun, and core biopsy guided by palpation. Needle track visualization, presence and amount of tumor displacement, tumor morphology, and interval between core biopsy and surgical excision were recorded for each case.

RESULTS

Seventy-six cases showed tumor displacement of one or two cell clusters, and 38 cases-showed displacement of multiple tumor fragments. Tumor displacement was identified in 37% of automated gun specimens, 38% of specimens obtained with palpable guidance, and 23% of specimens obtained with a vacuum-assisted needle. Tumor displacement was seen in 42% of patients with an interval between biopsy and excision of less than 15 days, in 31% of patients with an interval of 15-28 days, and in 15% of tumors excised more than 28 days after core biopsy (p < .005).

CONCLUSION

Tumor cell displacement was observed in 32% of patients who had undergone large-gauge needle core biopsy. The incidence and amount of tumor displacement was inversely related to the interval between core biopsy and excision. This relation suggests that tumor cells do not survive displacement.

Imaging features of focal breast fibrosis: mammographic-pathologic correlation of noncalcified breast lesions

OBJECTIVE

Our objective was to describe the spectrum of imaging and histologic findings of focal breast fibrosis with an emphasis on noncalcified lesions, thereby offering a means of confirming mammographic-pathologic concordance on core biopsy of this increasingly encountered diagnosis.

MATERIALS AND METHODS

Retrospective review of 610 core needle biopsies revealed the histologic diagnosis of focal fibrosis in 89 (15%). Thirty-nine cases were excluded: 17 in which focal fibrosis was not the primary diagnosis and 22 in which calcifications were the main imaging findings. The 50 remaining patients with noncalcified lesions that proved on histology to be focal fibrosis constituted the basis of the study.

RESULTS

Mammographically, focal fibrosis presented as a mass in 68% of patients (n = 34), architectural distortion in 12% (n = 6), and asymmetric density in 10% (n = 5); focal fibrosis was mammographically occult in 10% (n = 5). Sonographically, 72% (n = 36) of cases of focal fibrosis presented as masses with three echo texture patterns: hypoechoic, isoechoic, and centrally echogenic with a peripheral hypoechoic rim. The sonographic margins were well circumscribed (n = 21), lobulated (n = 10), or ill defined (n = 5). Histologic review revealed three morphologic patterns of collagen deposition: perilobular, septal, and haphazard fibrosis. Correlation with the imaging findings showed that septal and perilobular fibrosis most often presented as hypoechoic or centrally echogenic masses, whereas the haphazard form was more often seen with architectural distortion.

CONCLUSION

Focal fibrosis often presents as a noncalcified mass on mammography or sonography. The diagnosis of focal fibrosis on core needle biopsy can be considered concordant for a mass exhibiting well-circumscribed or partially obscured margins. Imaging findings discordant with focal fibrosis, such as marginal spiculation, require excisional biopsy.

Sonographic evaluation of infiltrating lobular carcinoma

OBJECTIVE

Infiltrating lobular carcinoma (ILC), which accounts for 7-10% of all breast malignancies, often poses diagnostic difficulties. The purpose of our study was to correlate the clinical, mammographic, and sonographic findings in each histologic subtype of ILC and to evaluate the sensitivity of sonography in its diagnosis.

MATERIALS AND METHODS

We reviewed 208 cases of invasive lobular carcinoma. In 81 of these tumors, sonography was performed to further examine a mammographically invisible palpable abnormality or a mammographically subtle lesion. A dedicated breast pathologist classified each of these tumors as pure invasive lobular carcinoma or mixed invasive lobular and ductal carcinoma. Pure ILC tumors were further subclassified as one of five histologic subtypes. We retrospectively studied the clinical, mammographic, and sonographic findings in each histologic tumor subtype.

RESULTS

The most common sonographic appearance of ILC was a heterogeneous, hypoechoic mass with angular or ill-defined margins and posterior acoustic shadowing, which was seen in 60.5% (49/81) of tumors. Of the remaining 32 tumors, 15% (12/81) showed focal shadowing without a discrete mass, 12% (10/81) appeared as a lobulated, well-circumscribed mass, and 12% (10/81) were sonographically invisible. Although considerable overlap occurred among histologic subtypes, classic ILC tended to present as focal shadowing without a discrete mass; pleomorphic ILC typically was seen as a shadowing mass; and, of all the tumor subtypes, signet, alveolar, and solid ILC were most likely to be revealed on sonography as a lobulated, well-circumscribed mass. In the 81 mammographically subtle or invisible lesions, sonography detected the tumor in 87.7% (71/81). The sensitivity of sonography in tumors smaller than 1 cm was 85.7% (12/14).

CONCLUSION

High-resolution sonography of the breast is a useful adjunct in the evaluation of ILC, a neoplasm that frequently presents a clinical and mammographic diagnostic challenge.

Ductography for nipple discharge: no replacement for ductal excision

BACKGROUND

Current management of nipple discharge depends on clinical history to distinguish pathologic from physiologic discharge. We investigated whether ductography supplied additional information in the decision for surgery and/or the localization of pathologic lesion.

METHODS

A retrospective review of patients with a presenting complaint of nipple discharge seen at the Lynn Sage Breast Center was conducted from January 1995 to June 1996. Medical records, pathology, and ductograms were reviewed.

RESULTS

Of 91 patients with nipple discharge, 49 met the criteria for physiologic discharge and 42 had pathologic discharge. Eleven with physiologic discharge had ductograms; none were abnormal. Four of 20 preoperative ductograms were normal but showed intraductal papillomas at the time of surgery; 6 of 20 (30%) had multiple lesions. Four lesions on ductograms did not demonstrate corresponding lesions in the surgical specimen. It is uncertain whether this is due to a missed lesion or a false-positive ductogram.

CONCLUSIONS

Modern ductography does not reliably exclude intraductal pathology and is not a substitute for surgery in patients with pathologic discharge. Its utility is in identifying multiple lesions or those with lesions in the periphery of the breast.

Improved diagnosis of breast implant rupture with sonographic findings and artificial neural networks

RATIONALE AND OBJECTIVES

The authors evaluated the use of sonographic findings combined with artificial neural networks as an aid to the diagnosis of breast implant rupture.

MATERIALS AND METHODS

From a database of 78 breast implants that were evaluated prospectively with sonography and then surgically removed, sonographic findings and surgical results were used to train and test backpropagation and radial basis function artificial neural networks by using the leave-one-out method. Receiver operating characteristic (ROC) curve analysis was used to compare the performance of the different neural networks with that of the radiologists involved.

RESULTS

By using the ROC area index as a measure of performance, the artificial neural network (Az = 0.8744) outperformed the radiologists (Az = 0.8057), although not by a statistically significant difference (P = .09). The best-performing network used, in addition to the sonographic findings, the diagnosis of the radiologist as an input. This network (Az = 0.9245) outperformed both the radiologists and the "unaided" networks by a statistically significant margin (P = .02 for radiologists, P = .04 for the unaided network). The network performed remarkably well in those cases in which the radiologists classified the implant as indeterminate, predicting the correct diagnosis in 23 of 25 cases (92%).

CONCLUSION

The results suggest that artificial neural networks in tandem with the unaided radiologic diagnosis can improve the accuracy rate in the detection of implant rupture based on sonographic findings. This "team" approach provided the best results.

Age and interval for screening mammography: whom do you believe?

The purpose of this article is to help the clinician understand the benefits and limitations of screening mammography in the 40-49 age group. Since the benefit of screening mammography is well established in the literature for the 50-59 age group, comparison of the relevant issues is focused on similarities and differences between these two age groups. The incidence of breast cancer, the effectiveness of mammography, and the growth rates of tumors influence the benefit derived from screening. Available data suggest that mammography is equally effective in both age groups, with similar detection rates of minimal cancer (27 vs. 25%). The difference in estimated annual incidence between the 40-49 and the 50-59 age group is only 8%. Since tumor growth rate seems to be faster in the younger age group, screening should be performed annually, starting at 40 years of age, if it is to provide a benefit.

Sonographic signs of breast implant rupture

OBJECTIVE

This study evaluated sonography as a screening test for breast implant rupture and developed diagnostic criteria for implant rupture.

SUBJECTS AND METHODS

Women contemplating implant removal were evaluated prospectively with sonography. Implants were classified as normal, indeterminate, or ruptured. Individual sonographic signs were analyzed for their statistic association with implant rupture. To measure the degree of interobserver variation, static images were evaluated by two different observers.

RESULTS

Of 236 implants evaluated, surgical confirmation was available in 78, 22 of which were ruptured and 56, intact. Echogenic noise, multiple discontinuous parallel linear echoes, and echodense aggregates in the implant lumen were statistically associated with rupture. Based on sonographic findings, we classified 34 implants as intact (at surgery: 31 intact, 3 ruptured). We classified 19 as ruptured (at surgery: 11 ruptured, 8 intact). Of the 25 implants we classified as indeterminate, 17 were intact and 8 were ruptured at surgery. Therefore, sonography had a positive predictive value of 58%, a negative predictive value of 91%, a sensitivity of 50%, and a specificity of 55%. Receiver operating characteristic analysis suggests a learning curve effect and no significant interobserver variation.

CONCLUSIONS

A normal sonographic result is highly predictive of an intact implant. Thus, sonography is useful in evaluating symptomatic women or women concerned about implant rupture. An indeterminate sonographic result suggests the need for further testing.

Sonographic evaluation of the breast

Knowledge of appropriate ultrasonographic (US) techniques and the US appearance of the normal breast and specific lesions is essential for successful application of breast US. The highest quality breast sonograms are achieved with 5-10-MHz linear transducers, imaging the lesion within the transducer focal zone, and relatively steep time-gain compensation curves. On sonograms, the fat in normal breast parenchyma is hypoechoic, fibrous tissue is echogenic, and glandular tissue is intermediate in echogenicity. Some normal structures can simulate masses, including the anterior costochondral junction when imaged in cross section and fat lobules outlined by Cooper ligaments when imaged in a perpendicular plane. Cysts have an anechoic interior, sharp margins, and posterior acoustic enhancement. Benign solid lesions are usually hypoechoic but variable in US appearance, which can overlap with that of complicated cysts. The classic US appearance of breast carcinoma is a hypoechoic mass with inhomogeneous internal echoes, irregular margins, and variable acoustic shadowing, although carcinoma can appear well circumscribed or have posterior acoustic shadowing in some cases. The most important function of breast US is differentiating a cyst from a solid lesion. US is also useful for evaluating a palpable mass in either young patients (< 30 years old) or those with dense breasts and negative mammographic results.

Tracheal and bronchial cartilaginous rings: warfarin sodium-induced calcification

Progressive calcification of the cartilaginous rings (CCR) of the trachea and bronchi has been observed in patients undergoing prolonged prophylactic anticoagulant therapy with warfarin sodium. The purpose of this study was to validate the relationship of warfarin sodium and CCR, as well as to present the appearance and sex and age distribution of the normal degenerative CCR seen in the elderly. Chest radiographs were scrutinized for evidence of CCR in 92 patients who underwent warfarin sodium therapy and in 105 patients used as a control group. CCR was classified as not present (scored as 0), subtle (scored as 1), and extensive (scored as 2). In the warfarin sodium study group, 47% of patients (43 of 92) exhibited level 1 or level 2 CCR. This proportion was 19% (20 of 105) in the control group. The difference was statistically significant (P less than .001). A significant positive correlation (P less than .001) was also present between the duration of warfarin sodium therapy and increased levels of CCR.

Value of diagnostic tests for deep venous thrombosis: a decision analysis model

A decision analysis model and data pooled from more than 12,000 patients were used to help elucidate conflicting results about the preferred method for diagnosing deep venous thrombosis (DVT). The prevalence of DVT in symptomatic legs is 40%, a value at which venography followed by Doppler ultrasound (in cases of nondiagnostic or unsuccessful venography) is preferred over the sequence of Doppler-plethysmography, provided that the sensitivity of the latter is less than 94%. If the prevalence of DVT decreases to 25% or the sensitivity of Doppler is 95% or higher, then the sequences of Doppler-plethysmography and venography-Doppler are equivalent in helping minimize resulting morbidity and mortality. Because of the greater clinical significance of proximal DVT, the analysis was modified to reflect changes in prevalence, sensitivity of noninvasive tests, and rate of pulmonary embolus due to DVT extending above the knee. In this case, performing plethysmography is slightly better than performing venography followed by Doppler or plethysmography.

A subclavian line complication: embolisation of an arteriovenous fistula

We report a case illustrating the successful non-surgical management of an arteriovenous fistula resulting from central line placement. After diagnosis by angiography transcatheter embolotherapy of the internal mammary artery provided an alternative to thoracotomy in treating this unusual complication.

Enhancement of pulmonary vasculature in pulmonary consolidation as seen by computed tomography

Computed tomography of the chest is often useful in evaluating lung consolidation and endobronchial obstruction. Our case demonstrates a consolidated lung associated with endobronchial obstruction and an interesting finding of enhanced pulmonary vasculature contrasted against surrounding pulmonary parenchyma of low density. We believe this represents the computed tomography appearance of drowned lung.