Efficacy of step-oblique mammography for confirmation and localization of densities seen on only one standard mammographic view.

OBJECTIVE: Step-oblique mammography is a technique used to determine with confidence whether a mammographic finding visible on multiple images on only one projection (but not elucidated using standard additional mammographic projections such as the roll view) represents a summation artifact or a true mass, and to precisely localize the true mass for further evaluation (if applicable). This paper describes the step-oblique technique and evaluates its efficacy. MATERIALS AND METHODS: Between January 1, 1993 and December 31, 1998, 69 consecutive women underwent step-oblique mammography for the evaluation of densities seen on multiple images in only one standard projection. Additional images were obtained at 15 degrees stepped increments in obliquity. If a one-projection-only finding was not seen on step-oblique images, the density was judged to represent a summation artifact, completing the examination. If a density was visualized and could be triangulated concordantly on step-oblique images ranging from the craniocaudal to the 90 degrees lateral projection, then it was judged to represent a real lesion. Such a lesion was further characterized (mass, neodensity, architectural distortion, focal asymmetric density) and was localized precisely in three dimensions, permitting imaging-guided tissue diagnosis, if appropriate. For all study patients, we also recorded BI-RADS (American College of Radiology Breast Imaging and Data Reporting System) assessment categories; pathology results for biopsied lesions; and mammographic follow-up, clinical follow-up, and linkage to regional tumor registry for nonbiopsied lesions for which at least 2 years had elapsed since step-oblique mammography. RESULTS: Step-oblique mammography differentiated 50 real lesions from 19 summation artifacts. All 50 real lesions, although initially visible on only one standard projection, were successfully localized in three dimensions. Subsequent management resulted in the prompt detection and diagnosis of seven breast cancers and 21 benign lesions. None of the remaining findings managed by follow-up rather than biopsy have subsequently been found to be malignant. CONCLUSION: Step-oblique mammography is an effective means of evaluating the mammographic finding visible on multiple images on only one standard projection.

Variability and accuracy in mammographic interpretation using the American College of Radiology Breast Imaging Reporting and Data System.

BACKGROUND: Several studies, which were limited by their small sample size and selection of difficult cases for review, have reported substantial variability among radiologists in interpretation of mammographic examinations. We have determined, in the largest study to date, intraobserver and interobserver agreement in interpreting screening mammography and accuracy of mammography by use of the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS). METHODS: The mammographic examinations were randomly selected on the basis of original mammographic interpretation and cancer outcome from 71,713 screening examinations performed by the Mobile Mammography Screening Program of the University of California, San Francisco, during the period from April 1985 through February 1995. The final sample included 786 abnormal examinations with no cancer detected, 267 abnormal examinations with cancer detected, and 1563 normal examinations. Films were read separately by two radiologists according to BI-RADS. Cancer status was determined by contacting women's physicians and by linkage to the regional Surveillance, Epidemiology, and End Results Program. RESULTS: There was moderate agreement between radiologists in reporting the presence of a finding when cancer was present (kappa = 0.54) and substantial agreement when cancer was not present (kappa = 0.62). Agreement was moderate in assigning one of the five assessment categories but was statistically significantly lower when cancer was present relative to when cancer was not present (kappa = 0.46 versus 0.56; two-sided P = .02). Agreement for reporting the presence of a finding and mammographic assessment was two-fold more likely for examinations with less dense breasts. Agreement was higher on repeat readings by the same radiologists than between radiologists. The sensitivity of mammography was lower with BI-RADS than with the original system for mammographic interpretation, but the positive predictive value of mammography was higher. CONCLUSION: Considerable variability in interpretation of mammographic examinations exists; this variability and the accuracy of mammography are neither improved nor diminished with use of BI-RADS.

Ovarian cancer: staging with CT and MR imaging.

PURPOSE: To evaluate ovarian cancer staging and tumor resectability with computed tomography (CT) or magnetic resonance (MR) imaging. MATERIALS AND METHODS: Eighty-two women underwent CT (n = 43) or MR imaging (n = 50); eleven of these 82 underwent both. Imaging was performed within 4 weeks of surgical staging. Radiologic, surgical, and histopathologic findings were compared. RESULTS: Overall staging accuracy was similar for CT and MR imaging (77% [33 of 43] vs 78% [39 of 50]). Evaluation of pelvic cancer extent was better with MR imaging than with CT. There was no difference in detection of abdominal disease. Most mesenteric and small-bowel implants were not detected with either CT or MR imaging. For CT, the positive predictive value for cancer nonresectability was 100% (three of three patients); the negative predictive value was 92% (37 of 40 patients). The positive and negative predictive values for MR imaging were 91% (10 of 11 patients) and 97% (38 of 39 patients). CONCLUSION: While the staging accuracy of both CT and MR imaging is only moderate, prediction of tumor resectability is excellent.

The comparative value of mammographic screening for women 40-49 years old versus women 50-64 years old.

OBJECTIVE: The purpose of our study was to compare the major prognostic factors (tumor size, axillary lymph node status, and tumor stage) of breast cancers detected at mammographic screening in women ages 40-49 years old with those in women ages 50-64 years old. MATERIALS AND METHODS: Study subjects were women ages 40-64 years old who participated in our mobile van mammographic screening program from April 1985 to June 1994. We retrospectively reviewed the clinical and pathology records of women in whom breast cancer was detected at mammographic screening. All examinations were performed with dedicated equipment using screen-film technique. RESULTS: A total of 44,301 screening examinations were done during the study period. Seventy-five cancers were detected in women ages 40-49 years old, and 128 cancers were detected in women ages 50-64 years old. The cancer detection rate was 3.0 per 1000 examinations in the younger age group compared with 5.5 per 1000 examinations in the older age group. The median size of breast cancers was 10 mm for women ages 40-49 versus 11 mm for women ages 50-64. Eighty-eight percent of the patients in both age groups had no evidence of metastasis to axillary lymph nodes. Nineteen percent of women in the younger age group had advanced breast cancer (stage II or higher) compared with 26% of women ages 50-64 (p = .25). No statistically significant differences were noted between the two age groups in the size, lymph node status, or stage of breast cancers detected at mammographic screening. However, the cancers found in younger women had slightly more favorable prognoses. CONCLUSION: The major prognostic factors of cancers detected with modern mammographic equipment appear to be at least as favorable for women ages 40-49 years old as for women ages 50-64 years old. As mammographic screening has already been shown to be beneficial for women ages 50-64 years old, screening should also be beneficial for women ages 40-49 years old.

Initial versus subsequent screening mammography: comparison of findings and their prognostic significance.

OBJECTIVE: The goal of this study was to compare findings on initial and subsequent screening mammograms to determine the prognostic significance of screening-detected abnormalities. MATERIALS AND METHODS: All 3386 abnormal examinations from a 9-year mammographic screening program were studied. An initial examination was defined as one for which there were no prior films available for comparison (even if one or more prior examinations had been performed); the remainder were called subsequent examinations. The principal mammographic feature of each abnormality was recorded, as well as whether a biopsy was performed. For all screening-detected cancers, we also determined several surrogate markers of prognosis (tumor size, presence of axillary lymph node metastasis, and tumor stage). These various parameters were analyzed as a function of initial versus subsequent screening. RESULTS: The frequency of abnormal examinations was more than 2 times greater for initial examinations (7%) than for subsequent examinations (3%). Only minor differences were noted between initial and subsequent screenings when comparing the principal mammographic features of the abnormalities. However, the number of cancers found per number of biopsies performed was significantly greater (p = .02) for subsequent screenings (41%) than for initial screenings (32%). Among the 333 cancers detected, tumor size was significantly smaller for subsequent screenings (p = .0076). Node-negative status and early tumor stage (stage 0 or 1) also were found more frequently for subsequently screened cancers, but these differences were not statistically significant. CONCLUSION: Substantially fewer abnormal screening interpretations are made when mammography has been performed previously and when the prior films are available for comparison. This results in cost savings and reduced morbidity at subsequent screening (no further work-up, less patient anxiety, fewer benign biopsies). Surrogate markers of prognosis also appear to be more favorable for cancers detected at subsequent screening.

Clinical efficacy of mammographic screening in the elderly.

PURPOSE: To compare mammographic screening results for women aged 65 years and older (elderly group) with those for women aged 50-64 years (younger group). MATERIALS AND METHODS: Mammography was performed in 32,140 women aged 50 years and older (10,914 elderly, 21,226 younger). Parameters studied included demographic data, screening interpretations, disposition of abnormal interpretations, results of biopsies, and characteristics of breast cancers. RESULTS: The cancer detection rate is substantially higher in elderly women (9.2 per 1,000 women) than in younger women (5.7 per 1,000 women). The median size of cancers in elderly women is 11 mm (vs 12 mm in younger women). Axillary nodal status is 93% node negative in elderly women (vs 88% node negative in younger women). Cancer stage is earlier in elderly women than it is in younger women (84% stage 0 or 1 vs 75% stage 0 or 1). CONCLUSION: Mammographic screening is at least as effective in detecting cancers for which there is a favorable prognosis in women aged 65 years and older as it is in women aged 50-64 years. Because the efficacy of screening in younger-group women has already been proved, it may be inferred that screening also benefits elderly-group women.

MRI of a silicone breast implant surrounded by an enlarging hemorrhagic collection.

MRI yields cross-sectional image acquisition in multiple planes with very high contrast resolution. Additionally, in MRI of the breast, evaluation of the entire implant is possible. Not only is MRI very sensitive to loss of implant integrity and rupture, but also MRI can evaluate and characterize adjacent fluid collections or soft-tissue masses. Anatomic relationships of abnormalities and normal structures are well seen. In some situations, MRI may offer clinically relevant information not adequately addressed by other imaging modalities.

Imaging techniques for breast MR imaging.

Specialized rf coils and pulse sequence techniques for contrast-enhanced breast imaging have been a focus of recent attention in MR imaging research. The imaging strategies for maximizing sensitivity and specificity involve trade-offs between spatial and temporal resolution. This article discusses these issues and others, such as considerations for coil design, fat suppression, patient positioning, motion artifact reduction, and methods for quantitative measurement of dynamic contrast enhancement.

Differentiation of silicone gel from water and fat in MR phase imaging of protons at 0.064 T.

The authors present a method of identifying silicone at magnetic resonance (MR) imaging based on its chemical shift. The method relies on phase images reconstructed from a gradient-recalled-echo sequence that has an echo time chosen to maximize the phase offsets between water, fat, and silicone. Results from studies at 0.064 T of both phantoms and human subjects are presented. This technique was useful in identifying extracapsular silicone and may be applicable at other field strengths.

The ovary. Computed tomography and magnetic resonance imaging.

CT and MR imaging can both contribute valuable clinical information in women with benign and malignant ovarian masses; the superior soft tissue contrast and multiplanar capabilities provided by MR imaging make it a valuable tool to evaluate the normal ovary, polycystic ovaries, endometriosis, and disorders of sexual differentiation. CT is currently the recommended modality to stage ovarian carcinoma, and peritoneal implants as small as 5 mm can be visualized. With the addition of contrast-enhanced images to conventional MR sequences, however, improved visualization of intratumoral architecture has also allowed for accurate MR characterization of benign versus malignant ovarian masses. Fat saturation techniques used with conventional MR sequences can also be used for definitive characterization of benign fat-containing teratomas and differentiate these tumors from hemorrhagic ovarian cysts or endometriomas. Finally, the detailed visualization of the normal-sized ovary on MR images provided by both the body coil and the new phased-array coil allows detection of the normal ovaries, ovarian follicles, and ovarian cysts throughout the premenopausal and postmenopausal years. Findings of polycystic ovarian syndrome, which cannot be evaluated by CT, are characteristic on MR images. MR is unparalleled in the evaluation of disorders of sexual differentiation because MR images can depict ectopic and normally positioned gonads and provide multiplanar depiction of the other pelvic organs and perineum as well. CT and MR imaging can provide valuable and specific clinical information about the ovary and benign and malignant ovarian disease.