Comparison of fibroglandular tissue distributions for microwave tomographic breast images with complementary MR T2 weighted images.

We have recently demonstrated good correlation between the recovered permittivity from microwave imaging (MIS) and the recovered water content from near infrared imaging (NIR) for a common set of normal patients undergoing associated breast examinations. We have subsequently conducted a small sample of comparison breast examinations between microwave imaging and MR to assess possible correlation between the location and extent of the fibroglandular as seen on MR images with increased permittivity zones of the microwave images. From various physiological and MR breast studies, it has been shown that the fibroglandular regions are generally comprised of significantly higher levels of water than the more dominant adipose tissue. The initial results of this study are quite encouraging and demonstrate obvious correlations between the permittivity and MR-recovered fibroglandular regions for a set of patients with widely varying tissue type variations. In addition, they illustrate the value of extracting diagnostic information from multiple modalities especially where the amount of direct in vivo property measurements is limited or nonexistent.

Quantitative hemoglobin tomography with diffuse near-infrared spectroscopy: pilot results in the breast.

The authors describe what is, to the best of their knowledge, the first quantitative hemoglobin concentration images of the female breast that were formed with model-based reconstruction of near-infrared intensity-modulated tomographic data. The results in 11 patients, including two with breast tumors with pathologic correlation, are summarized. Hemoglobin concentration appears to correlate with tumor vascularity without the need for exogenous contrast material and thereby has intrinsic diagnostic value.

Initial studies of in vivo absorbing and scattering heterogeneity in near-infrared tomographic breast imaging.

Simultaneously recovered absorption and scattering images that separate these optical property features within the female breast are demonstrated from frequency-domain measurements. A study of known absorbing and scattering objects is presented as a foundation for interpreting these in vivo images once the contrast space has been fully characterized. No measurable influence of absorbing-object contrast appears in the scattering images, whereas localized scattering contrast enhances the corresponding region within the absorption image by approximately 30% (e.g., a 2:1 scatterer also reconstructs as an approximately 1.3:1 absorber). Scattering and absorption images of a female volunteer with a 3.4-cm fibroadenoma show a clear 2:1 localized increase in absorption coefficient with little or no evidence of scattering enhancement in the lesion.

Mammography in 53,803 women from the New Hampshire mammography network.

PURPOSE: To describe measures of mammography performance in a geographically defined population and evaluate the interpreter's use of the Breast Imaging Reporting and Data System (BI-RADS). MATERIALS AND METHODS: Mammographic data from 47,651 screening and 6,152 diagnostic examinations from November 1, 1996, to October 31, 1997, were linked to 1,572 pathologic results. Mammographic outcomes were based on BI-RADS assessments and recommendations reported by the interpreting radiologist. The consistency of BI-RADS recommendations was evaluated. RESULTS: Screening mammography had a sensitivity of 72.4% (95% CI: 66.4%, 78.4%), specificity of 97.3% (95% CI: 97.25%, 97.4%), and positive predictive value of 10.6% (95% CI: 9.1%, 12.2%). Diagnostic mammography had higher sensitivity, 78.1% (95% CI: 71.9%, 84.3%); lower specificity, 89.3% (95% CI: 88.5%, 90.1%); and better positive predictive value, 17.1% (95% CI: 14.5%, 19.8%). The cancer detection rate with screening mammography was 3.3 per 1,000 women, with a biopsy yield of 22.4%, whereas the interval cancer rate was 1. 2 per 1,000. Nearly 80% of screening-detected invasive malignancies were node negative. The recall rate for screening mammography was 8. 3%. Ultrasonography was used in 3.5% of screening and 17.5% of diagnostic examinations. BI-RADS recommendations were generally consistent, except for probably benign assessments. CONCLUSION: The sensitivity of screening mammography in this population-based sample is lower than expected, although other performance indicators are commendable. BI-RADS "probably benign" assessments are commonly misused.

Current medicolegal and confidentiality issues in large, multicenter research programs.

The convenience of fast computers and the Internet have encouraged large collaborative research efforts by allowing transfers of data from multiple sites to a single data repository; however, standards for managing data security are needed to protect the confidentiality of participants. Through Dartmouth Medical School, in 1996-1998, the authors conducted a medicolegal analysis of federal laws, state statutes, and institutional policies in eight states and three different types of health care settings, which are part of a breast cancer surveillance consortium contributing data electronically to a centralized data repository. They learned that a variety of state and federal laws are available to protect confidentiality of professional and lay research participants. The strongest protection available is the Federal Certificate of Confidentiality, which supersedes state statutory protection, has been tested in court, and extends protection from forced disclosure (in litigation) to health care providers as well as patients. This paper describes the careful planning necessary to ensure adequate legal protection and data security, which must include a comprehensive understanding of state and federal protections applicable to medical research. Researchers must also develop rules or guidelines to ensure appropriate collection, use, and sharing of data. Finally, systems for the storage of both paper and electronic records must be as secure as possible.

Mammography in New Hampshire: characteristics of the women and the exams they receive.

New Hampshire (NH) is one of two states that has developed a population-based mammography registry. The purpose of this paper is to describe what we have learned about mammography use in New Hampshire. After collecting data for 20 months, the database contains almost 110,000 mammographic encounters representing 101,679 NH women, who range in age from 18 to 97 with a mean of 56.7 years (SD=10.91). Education levels are high with 92% having a high school education and 59% with some college. Forty-six percent report their primary insurance is private, 29% report HMO/PPO coverage, and 25% receive federal health care assistance. Risk factors represented in the database include (categories not mutually exclusive) advancing age (60% over age 50), hormone replacement therapy use by menopausal women (40.6%), and a family history of breast cancer (29%). Penetration of mammography relative to the NH population is higher for younger age groups (40-48% for those aged 44-64) than older age groups (34-39% for those aged 65-84). The majority of mammographic encounters are routine screening exams (86%), often interpreted as negative or normal with benign findings (88%). Use of comparison films to interpret either diagnostic or screening mammography occurred in 86% of encounters. We have matched 3,877 breast pathology records to these mammographic encounters. The distribution of pathology outcomes for diagnostic exams was very similar to that for screening exams (approximately 65% benign, 17% invasive breast cancer, and 6% noninvasive breast cancer). Overall, we have designed a system that is well accepted by the NH community. Challenges include careful monitoring of data for coding errors, and a limitation of linking variables in mammography and pathology data. Data represented in this registry are a critical resource for research in mammographic screening and breast cancer early detection.

Multifrequency electrical impedance imaging: preliminary in vivo experience in breast.

We have deployed a recently completed spectroscopic electrical impedance tomography (EITS) imaging system in a small series of women (13 participants accrued to date) in order to investigate the feasibility of delivering EITS breast examinations on a routine basis. Hardware is driven with sinusoidally varying spatial patterns of applied voltage delivered to 16 electrodes over the 10 kHz to 1 MHz spectral range using a radially translating interface which couples the electrodes to the breast through direct contact. Imaging examinations have consisted of the acquisition of multi-channel measurements at ten frequencies on both breasts. Participants lie prone on an examination table with the breast to be imaged pendant in the electrode array that is located below the table. Examinations were comfortable and easy to deliver (about 10 minutes per breast including electrode-positioning time). Although localized near-surface electrode artefacts are evident in the acquired images, several findings have emerged. Permittivity images have generally been more informative than their conductivity counterparts, except in the case of fluid-filled cysts. Specifically, the mammographically normal breast appears to have characteristic absolute EITS permittivity and conductivity images that emerge across subjects. Structural features in the EITS images have correlated with limited clinical information available on participants with benign and malignant abnormality, cysts and scarring from previous lumpectomy and follow-up radiation therapy. Several cases from this preliminary experience are described.

Accuracy of prenatal sonography for detecting circumvallate placenta.

OBJECTIVE: We determined the accuracy of prenatal sonography for detecting placental circumvallation, a placental abnormality associated with increased fetal morbidity and mortality. MATERIALS AND METHODS: We analyzed 62 healthy pregnant (range, 18-36 weeks) patients with focused placental sonography for detection of morphologic abnormality using the published criteria for circumvallate placenta (irregular edge, uplifted margin, or placental sheet or shelf). Placental marginal sonograms were taken at 30 degrees intervals around the entire placental margin. Five experienced sonologists who were unaware of the pathologic findings independently reviewed the placental images and graded the placentas from 1 (definitely normal) to 5 (definitely circumvallate). Receiver operating characteristic (ROC) curves and area under the ROC curve were calculated for each reader. Gross and microscopic pathology was used as the gold standard for all cases. RESULTS: In the 62 patients, sonography revealed 49 normal placentas (79%), 12 partially circumvallate placentas (19%), and one completely circumvallate placenta (2%). ROC curves for the reviewers resulted in values for area under the curve ranging from .39 to .58. The sonologist who achieved the highest value for the area under the curve classified the 13 cases of proven circumvallation as one case of definite circumvallation, four cases as uncertain or equivocal, and eight cases as probably or definitely normal placentas. Of the normal placentas, 35% were graded as probably or definitely circumvallate by at least one sonologist. All sonologists misgraded the case of complete circumvallation as normal. CONCLUSION: Focused placental sonograms interpreted by experienced sonologists fail to detect the placental edge abnormality in most cases of circumvallation. In our study, 17 of 49 normal placentas were diagnosed as probably or definitely circumvallate by one or more observers. Our sonologists' interpretations of sonograms showed that complete circumvallation was difficult to assess. Although our study had a limited number of patients, the accuracy of sonography of the placenta for revealing circumvallation appears to be limited.

The New Hampshire Mammography Network: the development and design of a population-based registry.

OBJECTIVE: Some authors have proposed a national mammography registry to improve and monitor breast diagnostic practices. However, issues such as confidentiality, accuracy, and direct and indirect costs are practical barriers to implementing such a registry. This paper describes the development and design of a population-based mammography registry in New Hampshire. The project's objectives are to assess the accuracy of mammography by comparing interpretive results with pathology and tumor-registry reports and to improve mammographic performance by reporting findings to facilities, radiologists, and pathologists statewide. MATERIALS AND METHODS: We recruited radiologists and pathologists through professional associations and facilities through site visits. Data used to develop and design the registry were collected during site visits, using structured face-to-face interview methods. Only one site refused to provide site-specific information. RESULTS: Facilities in New Hampshire estimated the annual mammographic volume to be approximately 148,000. We have noted a great deal of variability in mammography practices. Their principal methods for determining screening versus diagnostic mammograms were by patient self-reports (44% of practices), referring physicians' reports (38%), and radiologists' reports (18%). Although 71% of practices have computers, only 16% have radiology information systems or hospital information systems that offer computerized patient-tracking capabilities. More than 90% of New Hampshire radiologists exclusively use freehand dictation for reporting, and although almost 50% codify reports, only 11% use the American College of Radiology lexicon. These data and concerns expressed by radiologists, pathologists, technologists, and administrators helped shape the New Hampshire registry. CONCLUSION: Heterogeneity of radiologic practices poses major challenges for implementing a population-based mammography registry. Issues such as confidentiality, the difficulty of assessing diagnostic acumen, and the time involved in providing data to a registry must be adequately addressed. For the registry to succeed in such diverse settings, researchers, radiologists, pathologists, technologists, and administrative staff must collaborate and cooperate.