Biomedical subjects

Constance Lehman

Publications and source records attributed to Constance Lehman.

8 recordsLinked to original sources

PubMed2006

Morphologic blooming in breast MRI as a characterization of margin for discriminating benign from malignant lesions.

RATIONALE AND OBJECTIVES: Develop a fully automated, objective method for evaluating morphology on breast magnetic resonance (MR) images and evaluate effectiveness of the new morphologic method for detecting breast cancers. MATERIALS AND METHODS: We present a new automated method (morphologic blooming) for identifying and classifying breast lesions on MR that measures margin sharpness, a characteristic related to blooming, defined as rapid enhancement, with a border that is initially sharp but becomes unsharp after 7 minutes. Independent training sets (98 biopsy-proven lesions) and testing sets (179 breasts, 127 patients, acquired at five institutions) were used. Morphologic blooming was evaluated as a stand-alone feature and as an adjunct to kinetics using free-response receiver operating characteristic and sensitivity analysis. Dependence of false-positive (FP) rates on acquisition times and pathologies of contralateral breasts were evaluated. RESULTS: Sensitivity of morphologic blooming was 80% with 2.46 FP per noncancerous breast: FPs did not vary significantly by acquisition times. FPs varied significantly by pathologies of contralateral breasts (cancerous contralateral: 4.29 FP/breast; noncancerous contralateral: 0.48 FP/breast; P < .0001). Evaluation of 45 cancers showed suspicious morphologies on 10/15 (67%) cancers with benign-like kinetics and suspicious kinetics on 5/10 (50%) cancers with benign-like morphologies. CONCLUSION: We present a new, fully automated method of identifying and classifying margin sharpness of breast lesions on MR that can be used to direct radiologists' attention to lesions with suspicious morphologies. Morphologic blooming may have important utility for assisting radiologists in identifying cancers with benign-like kinetics and discriminating normal tissues that exhibit cancer-like enhancement curves and for improving the performance of computer-aided detection systems.

Adult↗

PubMed2006

MRI-guided breast interventions.

The use of breast magnetic resonance imaging (MRI) in the diagnosis, staging, and management of breast cancer is rapidly increasing. MRI has the ability to detect malignancy that is occult to physical exam, ultrasound, and mammography. These qualities necessitate methods for MRI-guided tissue sampling. This article reviews all previously published and currently accepted methods for MRI-guided tissue sampling. The data to support these techniques are provided where appropriate. A detailed technique for vacuum-assisted breast biopsy is included. We will also review the data on other MRI-guided breast interventions such as transcutaneous tissue ablation.

Biopsy↗

PubMed2006

Diagnostic architectural and dynamic features at breast MR imaging: multicenter study.

PURPOSE: To prospectively determine the prevalence and predictive value of three-dimensional (3D) and dynamic breast magnetic resonance (MR) imaging and contrast material kinetic features alone and as part of predictive diagnostic models. MATERIALS AND METHODS: The study protocol was approved by the institutional review board or ethics committees of all participating institutions, and informed consent was obtained from all participants. Although study data collection was performed before HIPAA went into effect, standards that would be compliant with HIPAA were adhered to. Data from the International Breast MR Consortium trial 6883 were used in the analysis. Women underwent 3D (minimum spatial resolution, 0.7 x 1.4 x 3 mm; minimal temporal resolution, 4 minutes) and dynamic two-dimensional (temporal resolution, 15 seconds) MR imaging examinations. Readers rated enhancement shape, enhancement distribution, border architecture, enhancement intensity, presence of rim enhancement or internal septations, and the shape of the contrast material kinetic curve. Regression was performed for each feature individually and after adjustment for associated mammographic findings. Multivariate models were also constructed from multiple architectural and dynamic features. Areas under the receiver operating characteristic curve (Az values) were estimated for all models. RESULTS: There were 995 lesions in 854 women (mean age, 53 years +/- 12 [standard deviation]; range, 18-80 years) for whom pathology data were available. The absence of enhancement was associated with an 88% negative predictive value for cancer. Qualitative characterization of the dynamic enhancement pattern was associated with an Az value of 0.66 across all lesion architectures. Focal mass margins (Az = 0.76) and signal intensity (Az = 0.70) were highly predictive imaging features. Multivariate models were constructed with an Az value of 0.880. CONCLUSION: Architectural and dynamic features are important in breast MR imaging interpretation. Multivariate models involving feature assessment have a diagnostic accuracy superior to that of qualitative characterization of the dynamic enhancement pattern.

Adolescent↗

PubMed2005

MRI detection of distinct incidental cancer in women with primary breast cancer studied in IBMC 6883.

BACKGROUND: Prior single institution studies suggest MRI may improve the assessment of the extent of cancer within the breast, and thus reduce the risk of leaving macroscopic disease in the breast following breast conservation therapy. We report on the rate of MRI and mammography detection of foci of distinct incidental cancer in a prospective, multi center trial involving 426 women with confirmed breast cancer at 15 institutions in the US, Canada, and Germany. METHODS: Women underwent mammography and MRI prior to biopsy of the suspicious index lesion. Additional incidental lesions (IL) greater than 2 cm from the index lesion that were detected by mammography and MRI were noted and characterized. Biopsy recommendations were associated with ILs given an assessment of suspicious or highly suspicous (BiRads 4 and 5). These assessments were considered a positive test. RESULTS: MRI had a significantly higher yield of confirmed cancer ILs than mammography (0.18 (95%CI: 0.142-0.214) for MRI versus 0.072 (95%CI: 0.050-0.100) for mammography). The cancer ILs detected by MRI alone appeared to be similar to those detected by mammography with respect to size and histology. The percentage of biopsies of ILs that resulted in a cancer diagnosis was similar between the modalities (MRI 0.72(95%CI: 0.6-0.81); Mammography 0.85 (95%CI: 0.62-0.96)). CONCLUSIONS: These results suggest that consideration needs to be given regarding the integration of breast MRI into the pretreatment evaluation of women seeking breast conservation therapy.

Biopsy↗

PubMed2004

Magnetic resonance imaging of the breast prior to biopsy.

CONTEXT: Breast magnetic resonance imaging (MRI) has been shown to have high sensitivity for cancer detection and is increasingly used following mammography to evaluate suspicious breast lesions. OBJECTIVE: To determine the accuracy of breast MRI in conjunction with mammography for the detection of breast cancer in patients with suspicious mammographic or clinical findings. DESIGN, SETTING, AND PATIENTS: Prospective multicenter investigation of the International Breast MR Consortium conducted at 14 university hospitals in North America and Europe from June 2, 1998, through October 31, 2001, of 821 patients referred for breast biopsy for American College of Radiology category 4 or 5 mammographic assessment or suspicious clinical or ultrasound finding. INTERVENTIONS: MRI examinations performed prior to breast biopsy; MRI results were interpreted at each site, which were blinded to pathological results. MAIN OUTCOME MEASURES: Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of breast MRI. RESULTS: Among the 821 patients, there were 404 malignant index lesions, of which 63 were ductal carcinoma in situ (DCIS) and 341 were invasive carcinoma. Of the 417 nonmalignant index lesions, 366 were benign, 47 showed atypical histology, and 4 were lobular carcinoma in situ. The AUC pooled over all institutions was 0.88 (95% confidence interval [CI], 0.86-0.91). MRI correctly detected cancer in 356 of 404 cancer cases (DCIS or invasive cancer), resulting in a sensitivity of 88.1% (95% CI, 84.6%-91.1%), and correctly identified as negative for cancer 281 of 417 cases without cancer, resulting in a specificity of 67.7% (95% CI, 62.7%-71.9%). MRI performance was not significantly affected by mammographic breast density, tumor histology, or menopausal status. The positive predictive values for 356 of 492 patients was 72.4% (95% CI, 68.2%-76.3%) and of mammography for 367 of 695 patients was 52.8% (95% CI, 49.0%-56.6%) (P<.005). Dynamic MRI did not improve the AUC compared with 3-dimensional MRI alone, but the specificity of a washout pattern for 123 of 136 patients without cancer was 90.4% (95% CI, 84%-95%). CONCLUSIONS: Breast MRI has high sensitivity but only moderate specificity independent of breast density, tumor type, and menopausal status. Although the positive predictive value of MRI is greater than mammography, MRI does not obviate the need for subsequent tissue sampling in this setting.

Adult↗

PubMed2004

Factors contributing to mammography failure in women aged 40-49 years.

BACKGROUND: Younger women (40-49 years) have lower mammographic sensitivity (i.e., greater proportion of cancers detected after a negative mammogram) than older women (> or =50 years). We explored the effect of tumor growth rate, breast density, mammographic image quality, and breast cancer risk factors on mammographic sensitivity in younger and older women. METHODS: We studied 576 women (n = 73 aged 40-49 years and n = 503 aged 50 years or older) who were diagnosed with invasive breast cancer between 1988 and 1993. Interval cancers were defined as those diagnosed within 12 or 24 months after a negative screening mammogram and before a subsequent mammogram. Tumor growth rate was assessed by mitotic figure count and Ki-67 positivity. The main outcome measures were percentage of women with interval cancer (1 -mammographic sensitivity) by age, odds ratio (OR) of interval cancer by age, and excess odds (i.e., the percentage of the odds ratio for age that was explained by individual covariates). RESULTS: Interval cancers occurred in 27.7% of younger women and 13.9% of older women within 12 months (OR = 2.36, 95% confidence interval [CI] = 1.14 to 4.77) and in 52.1% of younger women and 24.7% of older women within 24 months (OR = 3.58, 95% CI = 2.15 to 5.97). Greater breast density explained 67.6% of the decreased mammographic sensitivity in younger women at 12 months, whereas rapid tumor growth explained 30.6% and breast density explained 37.6% of the decreased sensitivity in younger women at 24 months. CONCLUSIONS: Breast density largely explained decreased mammographic sensitivity at 12 months, whereas rapid tumor growth contributed to decreased mammographic sensitivity at 24 months. A 12-month versus a 24-month mammography screening interval may therefore reduce the adverse impact of faster growing tumors on mammographic sensitivity in younger women.

Adult↗

PubMed2002

Use of the American College of Radiology BI-RADS guidelines by community radiologists: concordance of assessments and recommendations assigned to screening mammograms.

OBJECTIVE: This study evaluated the use of the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) by community radiologists by determining the concordance of assessment categories and recommendations assigned to screening mammograms. MATERIALS AND METHODS: The study comprised the interpretations of 82,620 consecutive screening mammograms by 18 radiologists between January 1, 1995, and December 31, 1998. For all mammograms, assessment categories and recommendations were compared to determine whether they were in accordance with BI-RADS guidelines. Overall patterns of discordance were analyzed, and comparisons of discordant patterns by assessment category, patient age, breast density, and year of examination were made. RESULTS: The overall discordance between BI-RADS assessments and recommendations was low (3%). The assessment with the highest discordance was "probably benign finding" (category 3), at 53.5%. Mammograms obtained in 1998 were almost half as likely to have assessment-recommendation discordance compared with those obtained in 1995 (2.4% vs 4.5%, respectively; odds ratio = 0.52; p < 0.001). Mammograms of women with dense breast tissue were 30% more likely to have lesions assigned discordant assessments and recommendations compared with those of women with fatty tissue (3.4% vs 2.7%, respectively; odds ratio = 1.3; p < 0.001). No differences in the patterns of discordance were found between mammograms of women younger than 50 years and those of women 50 years old and older (p = 0.10). CONCLUSION: There has been improvement in the accurate application of BI-RADS since its introduction. However, variation in the pairing of BI-RADS assessments and recommendations persists. Continued efforts to educate radiologists about the use of BI-RADS and to clarify BI-RADS terms would promote maximum consistency in this use of this reporting method.

Adult↗

PubMedDate not supplied

Overview of breast health care guidelines for countries with limited resources.

Among women around the globe, breast cancer is both the most common cancer and the leading cause of cancer-related death. Women in economically disadvantaged countries have a lower incidence of breast cancer, but poorer survival rates for the disease relative to women in affluent countries. Evidence suggests that breast cancer mortality can be reduced if resources are applied to the problem in a systematic way. The purpose of the Global Summit Consensus Conference was to begin a process to develop guidelines for improving breast health care in countries with limited resources-those with either low- or medium-level resources based on World Health Organization (WHO) criteria. Breast cancer experts and patient advocates representing 17 countries and 9 world regions participated in the conference. They reviewed the existing breast health guidelines, which generally assume unlimited resources. Individual panels then discussed and debated how limited resources can best be applied to improve three areas of breast health care--early detection, diagnosis, and treatment--and how to integrate these areas in building a breast health care program. The panelists unanimously agreed on the guiding principle that all women have the right to access to health care. They also agreed that collecting data on breast cancer is imperative for deciding how best to apply resources and for measuring progress. The panelists acknowledged the considerable challenges in implementing breast health care programs when resources are limited, as well as the need to build a program that is specific to each country's unique situation. The panelists noted that the development of centralized, specialized cancer centers may be a cost-effective way to deliver breast cancer care to some women when it is not possible to deliver such care to women nationwide. In countries with limited resources, at least half of the women have advanced or metastatic breast cancer at the time of diagnosis. Because advanced breast cancer has the poorest survival rate and is the most resource intensive to treat, measures to reduce the stage at diagnosis are likely to have the greatest overall benefit in terms of both survival and costs. Women should have access to diagnosis and treatment if efforts are undertaken to improve early detection of breast cancer. The panels' findings outline specific steps for prioritizing the use of limited resources to decrease the impact of breast cancer around the globe.

Breast Neoplasms↗