PubMed Health⌕ Search

Biomedical subjects

E F Conant

Publications and source records attributed to E F Conant.

At least 19 recordsLinked to original sources
PubMed2005

Diffuse boundary extraction of breast masses on ultrasound by leak plugging.

We propose a semiautomated seeded boundary extraction algorithm that delineates diffuse region boundaries by finding and plugging their leaks. The algorithm not only extracts boundaries that are partially diffuse, but in the process finds and quantifies those parts of the boundary that are diffuse, computing local sharpness measurements for possible use in computer-aided diagnosis. The method treats a manually drawn seed region as a wellspring of pixel "fluid" that flows from the seed out towards the boundary. At indistinct or porous sections of the boundary, the growing region will leak into surrounding tissue. By changing the size of structuring elements used for growing, the algorithm changes leak properties. Since larger elements cannot leak as far from the seed, they produce compact, less detailed boundary approximations; conversely, growing from smaller elements results in less constrained boundaries with more local detail. This implementation of the leak plugging algorithm decrements the radius of structuring disks and then compares the regions grown from them as they increase in both area and boundary detail. Leaks are identified if the outflows between grown regions are large compared to the areas of the disks. The boundary is plugged by masking out leaked pixels, and the process continues until one-pixel-radius resolution. When tested against manual delineation on scans of 40 benign masses and 40 malignant tumors, the plugged boundaries overlapped and correlated well in area with manual tracings, with mean overlap of 0.69 and area correlation R2 of 0.86, but the algorithm's results were more reproducible.

Algorithms↗
PubMed2001

The impact of a multidisciplinary breast cancer center on recommendations for patient management: the University of Pennsylvania experience.

BACKGROUND: Advances in the diagnosis and treatment of breast carcinoma have led to a multidisciplinary approach to management for patients with breast carcinoma. To assess the effect of this approach, the authors performed an evaluation for a cohort of patients examined in a multidisciplinary breast cancer center. METHODS: An analysis was performed for the records of 75 consecutive women with 77 breast lesions examined in consultation in a multidisciplinary breast cancer center between January and June 1998. Each patient's case was evaluated by a panel consisting of a medical oncologist, surgical oncologist, radiation oncologist, pathologist, diagnostic radiologist, and, when indicated, plastic surgeon. A comprehensive history and physical examination was performed, and the relevant mammograms, pathology slides, and medical records were reviewed. Treatment recommendations made before this evaluation were compared with the consensus recommendations made by the panel. RESULTS: For the 75 patients, the multidisciplinary panel disagreed with the treatment recommendations from the outside physicians in 32 cases (43%), and agreed in 41 cases (55%). Two patients (3%) had no treatment recommendation before consultation. For the 32 patients with a disagreement, the treatment recommendations were breast-conservation treatment instead of mastectomy (n = 13; 41%) or reexcision (n = 2; 6%); further workup instead of immediate definitive treatment (n = 10; 31%); treatment based on major change in diagnosis on pathology review (n = 3; 9%); addition of postmastectomy radiation treatment (n = 3; 9%); or addition of hormonal therapy (n = 1; 3%). CONCLUSIONS: The multidisciplinary breast cancer evaluation program provided an integrated program in which individual patients were evaluated by a team of physicians and led to a change in treatment recommendation for 43% (32 of 75) of the patients examined. This multidisciplinary program provided important second opinions for many patients with breast carcinoma.

Adult↗
PubMed2001

Interreader variability and predictive value of US descriptions of solid breast masses: pilot study.

RATIONALE AND OBJECTIVES: This study evaluated the specificity of ultrasound (US) characteristics of solid breast lesions and the interreader variability in their interpretation. MATERIALS AND METHODS: In 61 patients, 70 sonographically visible solid masses, scheduled for biopsy because of findings from conventional imaging, were prospectively and sequentially accrued for evaluation. Three readers interpreted the sonograms and described the solid masses in terms of established US characteristics. The specificity and positive predictive value (PPV) for each characteristic were calculated by comparing US findings with biopsy findings, and interreader variability was evaluated. Five assessment categories were developed to guide recommendations for patient care. The relative performance of each reader was assessed by measuring the PPV for each assessment category and by measuring the area under the receiver operating characteristic curve. RESULTS: The specificity and PPV were calculated for all characteristics and for each reader. The average specificities of the three readers for the most frequently used six characteristics were as follows: spiculation, 97%+/-5 (standard deviation); taller than wide, 91%+/-4; central shadowing, 77%+/-1; markedly hypoechoic, 86%+/-5; duct extension, 95%+/-5; and microlobulation, 84%+/-3 (overall average specificity, 88.5%). The average PPVs for categories II-V were 5%, 10%, 63%, and 94%, respectively. The readers' interpretations were similar and correlated well. CONCLUSION: The proposed US recommendation system is an accurate predictor of histologic findings. A sonographic classification lexicon should prove valuable.

Breast↗
PubMed2001

Breast tissue density quantification via digitized mammograms.

Studies reported in the literature indicate that breast cancer risk is associated with mammographic densities. An objective, repeatable, and a quantitative measure of risk derived from mammographic densities will be of considerable use in recommending alternative screening paradigms and/or preventive measures. However, image processing efforts toward this goal seem to be sparse in the literature, and automatic and efficient methods do not seem to exist. In this paper, we describe and validate an automatic and reproducible method to segment dense tissue regions from fat within breasts from digitized mammograms using scale-based fuzzy connectivity methods. Different measures for characterizing mammographic density are computed from the segmented regions and their robustness in terms of their linear correlation across two different projections--cranio-caudal and medio-lateral-oblique--are studied. The accuracy of the method is studied by computing the area of mismatch of segmented dense regions using the proposed method and using manual outlining. A comparison between the mammographic density parameter taking into account the original intensities and that just considering the segmented area indicates that the former may have some advantages over the latter.

Algorithms↗
PubMed2001

Blinded review of retrospectively visible unreported breast cancers: an eye-position analysis.

PURPOSE: To determine whether unreported retrospectively identified cancers on mammograms receive prolonged visual attention and can be reliably detected in a blinded review. MATERIALS AND METHODS: Four experienced mammographers performed a blinded review of a test set of 20 retrospective cases where the cancer was not detected until the next mammographic evaluation, 10 prospective cases where the cancer was initially detected, and 10 cancer-free cases. Two views were digitized and displayed on a workstation. The experiment consisted of an initial impression, during which eye position was monitored, and a final impression, during which viewers zoomed on regions of interest and localized suspicious lesions. Eye-position data were analyzed to determine whether retrospectively visible cancers attracted attention to the same degree as prospectively visible cancers. The initial impression used 1,000 msec as the eye-fixation dwell criterion for detecting a lesion. RESULTS: Initially, 70% of retrospective cancers and 50% of prospective cancers did not attract prolonged visual attention. In prospective cases, detailed examination significantly improved the mean receiver operating characteristic area, from.73 to.88 (P <.01), but in retrospective cases, the mean receiver operating characteristic area barely increased, from.60 to.68, due to a high true-positive-to-false-positive ratio. CONCLUSION: At blinded review, detection of retrospectively visible cancers was significantly inferior to that of prospective cancers. It cannot be assumed that retrospectively identified cancers are intrinsically detectable, because they do not draw prolonged visual attention during visual search for breast cancers.

Breast Neoplasms↗
PubMed2001

Diabetic mastopathy in men: imaging findings in two patients.

The classic imaging findings of diabetic mastopathy, an uncommon entity manifesting in patients with a history of long-standing insulin-dependent diabetes mellitus, have been reported in the literature in women but not, to the authors' knowledge, in men. Two men with diabetic mastopathy presented with palpable breast masses. The clinical histories of the men in whom this condition was diagnosed were similar to those reported for women with the condition. The mammographic findings in both men, at presentation, were suggestive of gynecomastia.

Adult↗
PubMed2001

Cyclosporin A-induced fibroadenomas of the breast: report of five cases.

Five female patients undergoing cyclosporin A therapy had newly developed breast masses. Masses were bilateral in three of the five patients and palpable in four patients. The imaging findings were suggestive of fibroadenomas, and biopsy results were used to confirm the diagnosis. With the development of new breast lesions in patients after transplantation surgery, the diagnosis of cyclosporin A-induced fibroadenomas should be considered.

Adolescent↗
PubMed2001

Update on digital mammography.

On January 28, 2000, the U.S. Food and Drug Administration (FDA) approved the first full-field digital mammography unit for clinical use. The approval occurred approximately ten years after a National Cancer Institute (NCI) expert panel determined that, of all emergent technologies, digital mammography held the greatest potential for improving breast cancer detection [1,2]. Currently, four types of digital mammographic systems are under clinical evaluation. This article will review the information from the early clinical trials on digital mammography and will attempt to define the potential impact of digital mammography on the clinical practice of breast imaging.

Journal Article↗
PubMed2000

Quantitative vascularity of breast masses by Doppler imaging: regional variations and diagnostic implications.

Seventy-four biopsy proven breast masses were imaged by color and power Doppler imaging to evaluate vascular pattern of malignant and benign breast masses. The images were analyzed for vascularity. The measurements were made over the entire mass as well as regionally at its core, at its periphery, and in the tissue surrounding it. The surgical specimens were analyzed for microvessel density. The diagnostic performance of Doppler sonographic vascularity indices was evaluated by receiver operating characteristic analysis. The malignant masses were 14 to 54% more vascular than the benign masses. Both types of masses were more vascular by ultrasonography than the tissue surrounding them. Whereas benign masses were 2.2 times more vascular than the surrounding tissue, the malignant masses were 5.0 times more vascular. In a subset of patients the regional vascularity at the core, periphery, and surrounding tissue by Doppler imaging exhibited a strong correlation (R2 > 0.9) with the corresponding histologic microvessel density measurements. Although the malignant masses exhibited a strong gradient in vascularity, core > periphery > surrounding tissue, the benign masses had relatively uniform distribution of vascularity. The area under the receiver operating characteristic curve (A(Z)) for the Doppler indices ranged from 0.56 +/- 0.07 to 0.65 +/- 0.07. A nonlinear analysis including age-specific values of Doppler indices improved the diagnostic performance to A(Z) = 0.85 +/- 0.06. In conclusion, quantitative Doppler imaging when used in combination with a nonlinear rule-based approach has the potential for differentiating between malignant and benign masses.

Adult↗
PubMed1999

Immunohistochemistry with pancytokeratins improves the sensitivity of sentinel lymph node biopsy in patients with breast carcinoma.

BACKGROUND: Sentinel lymph node (SLN) biopsy is being investigated as a staging procedure for breast carcinoma. The authors evaluated whether immunohistochemical (IHC) analysis improves the sensitivity of this procedure. METHODS: Forty-four women with breast carcinoma were recruited for SLN biopsy. Preoperative lymphoscintigraphy was followed by intraoperative localization using a handheld gamma probe and blue dye. After SLN identification, an immediate complete axillary lymph node dissection was performed in all patients. All lymph nodes were subjected to routine histology (hematoxylin and eosin [H&E]) and IHC using antibody to cytokeratins. RESULTS: The SLN was identified in 41 of 43 patients (95%). Successful SLN identification was independent of biopsy technique (open surgical [95%] vs. fine-needle aspiration/core needle biopsy [96%]). Twelve of 41 patients (29%) had evidence of lymph node metastasis in the SLN by routine histology. Of the twenty-nine patients with H&E negative SLN, 3 were found to have metastasis by IHC for a conversion rate of 10%. Fifteen of 41 patients (37%) had evidence of metastasis in SLN. All 26 patients with H&E and IHC negative SLN had negative nonsentinel lymph nodes by routine histology and IHC (100% negative predictive value). All patients with tumors < 2 cm and micrometastasis to the SLN had no additional lymph node disease, in contrast to patients with lesions > 2 cm or patients with macrometastasis to the SLN (P = 0.007). CONCLUSIONS: These results confirm that SLN biopsy is extremely accurate for patients with breast carcinoma, even after open surgical biopsy. IHC analysis or serial sectioning of SLN improves the sensitivity of this staging technique.

Adult↗
PubMed1999

How experience and training influence mammography expertise.

RATIONALE AND OBJECTIVES: The authors evaluated the influence of perceptual and cognitive skills in mammography detection and interpretation by testing three groups representing different levels of mammography expertise in terms of experience, training, and talent with a mammography screening-diagnostic task. MATERIALS AND METHODS: One hundred fifty mammograms, composed of unilateral cranial-caudal and mediolateral oblique views, were displayed in pairs on a digital workstation to 19 radiology residents, three experienced mammographers, and nine mammography technologists. One-third of the mammograms showed malignant lesions; two-thirds were malignancy-free. Observers interacted with the display to indicate whether each image contained no malignant lesions or suspicious lesions indicating malignancy. Decision time was measured as the lesions were localized, classified, and rated for decision confidence. RESULTS: Compared with performance of experts, alternative free response operating characteristic performance for residents was significantly lower and equivalent to that of technologists. Analysis of overall performance showed that, as level of expertise decreased, false-positive results exerted a greater effect on overall decision accuracy over the time course of image perception. This defines the decision speed-accuracy relationship that characterizes mammography expertise. CONCLUSION: Differences in resident performance resulted primarily from lack of perceptual-learning experience during mammography training, which limited object recognition skills and made it difficult to determine differences between malignant lesions, benign lesions, and normal image perturbations. A proposed solution is systematic mentor-guided training that links image perception to feedback about the reasons underlying decision making.

Analysis of Variance↗
PubMed1996

Quantitative ultrasonic diagnosis of silicone breast implant rupture: an in vitro feasibility study.

Ultrasound is useful in evaluating the integrity of silicone breast implants. However, extensive operator experience is required. A system for computer-assisted diagnosis is being developed to reduce operator dependence. Feasibility was examined by measuring the ultrasonic properties of breast implants in vitro. Silicone gels from 45 explanted implants (26 intact and 19 ruptured) were placed in sealed acoustic test chambers and 60 RF A-lines were acquired from each. Velocity of sound, attenuation and integrated backscatter (IB) were estimated. Receiver operating characteristic (ROC) analysis was performed. The mean speed of sound was 1060 m/s +/- 50.1 m/s in intact implants and 1115 m/s +/- 74.3 m/s in ruptured ones (p < 0.003). Differences in attenuation were not statistically significant. The mean IB was -83.9 dB +/- 7.94 dB in intact and -77.2 dB +/- 9.07 dB in ruptured implants (p < 0.006). The area under the ROC curve (Az) was 0.70 and 0.73 for IB and velocity, respectively, while combining the two yielded Az = 0.81. Changes in speed of sound and IB, with changes in integrity of breast implants, have been demonstrated in vitro. The results indicate the potential for quantitative assessment of silicone breast implants performed in vivo.

Breast Implants↗
PubMed1996

Lung involvement in systemic sclerosis (scleroderma): relation to classification based on extent of skin involvement or autoantibody status.

Lung involvement accounts for significant morbidity and is a leading cause of mortality in patients with systemic sclerosis (SSc). It has been shown that different patterns of pulmonary involvement are seen in different subtypes of SSc. This paper reports a retrospective review of 72 patients with SSc to determine whether disease classification according to the extent of skin involvement alone (diffuse vs. limited) or autoantibody status was predictive of pulmonary parenchymal involvement. The diagnosis of interstitial lung disease was based on pulmonary function tests and chest radiographs. Restrictive lung disease was common in both limited SSc (lSSc) and diffuse SSc (dSSc), occurring in 30% and 50% of these patients respectively (P = 0.16). Radiographic evidence of significant interstitial disease was also comparable between the groups [nine of 32 lSSc patients (28%) vs. six of 17 dSSc patients (32%), P = n.s.]. No significant difference in mean lung function was found between patients with anti-Scl 70 antibody (n = 12) compared to those without (n = 60) (TLC 79.0 +/- SE 5.1% predicted vs. 82.8 +/- 2.2, P = n.s.; DLCO 63.0 +/- 5.1 vs. 59.7 +/- 2.5, P = n.s.). By contrast, statistically significant differences in mean lung function were found between patients with anticentromere antibody (ACA) (n = 24) and those without ACA (n = 48) (TLC 98.6 +/- SE 3.9% predicted vs. 79.7 +/- 3.1%, P < 0.001); and less frequent radiographic evidence of severe interstitial disease (0 of 17 with significant interstitial changes on chest radiograph vs. 15 of 32 (47%), P = 0.002). It is concluded that classification of SSc patients on the basis of the distribution of skin involvement poorly predicts the occurrence of interstitial lung disease. On the other hand, ACA is highly associated with the absence of interstitial lung disease.

Adult↗
PubMed1995

Bilateral breast carcinoma: mammographic and histologic correlation.

PURPOSE: To determine the mammographic, histologic, and clinical features of bilateral breast cancer. MATERIALS AND METHODS: Pre-biopsy mammograms of 67 patients with bilateral carcinoma were reviewed. Lesions were synchronous in 35 patients and metachronous in 32. Mammographic appearance, lesion size and location, and bilateral similarities were evaluated. Axillary nodal status was noted. These characteristics were compared with those of unilateral cancers. RESULTS: Of 58 mammographically evident lesion pairs, 31 involved the same quadrant. Of the total 67 lesion pairs, 24 pairs were similar in appearance, and 15 had both mirror image location and a similar appearance. Of 17 lesion pairs considered to represent a single primary carcinoma with metastases to the contralateral breast, eight had a similar mirror image appearance and five had mirror image location and a similar mirror image appearance. The second cancer of metachronous pairs was smaller, with less frequent axillary nodal involvement. CONCLUSION: The appearance of bilateral breast cancer does not differ from that of unilateral carcinoma. Bilateral breast carcinomas frequently demonstrate a similar mammographic appearance and mirror image location.

Adult↗
PubMed1994

Mammographically detected breast cancer. Nonpalpable is not a synonym for inconsequential.

BACKGROUND: Needle-guided breast biopsy has become a regularly recommended procedure to excise nonpalpable, questionable breast lesions detected by mammography. Whether cancers detected in this manner have a more favorable outcome than those detected by clinical examination is not clearly documented. METHODS: To address questions about the biology of mammographically detected cancer and likelihood of axillary node metastasis, as well as the accuracy of screening mammography, data from 3752 needle-guided breast biopsies and 1175 nonpalpable breast cancers were reviewed. RESULTS: Between 1974 and 1992, 3752 needle-guided biopsies were performed in 3441 women for nonpalpable breast lesions. Benign disease was disclosed in 2575 (68.7%) biopsies and malignancy in 1175 (31.3%). Of 1130 malignancies, 61.8% were invasive carcinomas; 4.8% were microinvasive ductal carcinomas; 28.5% were ductal carcinomas in situ; and 4.8% were lobular carcinomas in situ. Axillary dissection in 558 patients with invasive carcinoma revealed that 27.1% had at least one positive axillary node. Of patients with invasive cancers presenting as nonpalpable calcifications alone, 27.5% had at least one positive axillary node. CONCLUSIONS: More than one fourth of patients with nonpalpable, invasive cancer in this series had axillary node metastasis. Therefore, axillary dissection is an important treatment consideration for all patients with invasive carcinoma, despite technique of detection. Ductal carcinomas in situ detected as limited calcifications do not require axillary dissection. In this study, 31% of biopsies proved the presence of malignancy, an acceptable and appropriate benign-to-malignant ratio.

Biopsy, Needle↗
PubMed1994

Breast implants: incidental findings on CT.

The mammographic, sonographic, and MR appearances of both normal and abnormal breast implants have been described. Breast implants are occasionally seen on chest CT scans obtained for other reasons; however, we know of no published reports on the CT findings in a series of patients with breast implants. We present a retrospective review of CT findings in 18 patients with 27 breast implants that illustrates the spectrum of findings that can be seen in asymptomatic patients.

Breast↗
PubMed1994

Imaging findings in mucin-containing carcinomas of the breast: correlation with pathologic features.

OBJECTIVE: Breast carcinomas may contain varying quantities of extracellular mucin. The purpose of this study was to correlate the mammographic and sonographic appearance of mucin-containing carcinomas of the breast with the histologic features of these tumors. MATERIALS AND METHODS: The tumor registry and breast imaging files at our institution identified 34 women with 37 mucin-containing breast carcinomas for which mammographic and histologic slides were available for review. By consensus, two radiologists determined the mammographic margin characteristics (circumscribed, microlobulated, indistinct, spiculated) and, when available, the sonographic properties of the carcinomas. Doubling time in days was estimated from sequential mammograms when possible. A pathologist reviewed the histologic slides and divided the 37 carcinomas into three categories based on the percentage by volume of mucin seen: pure mucinous (> or = 90% mucin), 23 cases; moderately mucinous (< 90% and > 30% mucin), seven cases; and minimally mucinous (< or = 30% mucin), seven cases. To determine the contribution of varying percentages of mucin to the radiologic appearance of the tumors, the margin characteristics were correlated with the histologic percentage of mucin, microscopic margin appearance (displacing or infiltrating), nuclear grade (I, II, III), and lymph node status. RESULTS: Tumors with circumscribed and microlobulated margins on mammography had a higher percentage of mucin histologically (p < .01; chi 2). A trend of slower growth rate on mammograms, lower histologic nuclear grade, and less frequent axillary node involvement were also seen in tumors with a higher percentage of mucin. Spiculated mammographic margins were seen when there were decreasing volumes of mucin and when tumor margins histologically were infiltrating; these tumors had higher nuclear grades and more frequent axillary node involvement (p < .01). CONCLUSION: The radiologic and pathologic correlation of mucin-containing breast carcinomas demonstrates that lesions with higher percentages of mucin have mammographic appearances that reflect less aggressive histologic margins, lower nuclear grades, and slower growth rates. Carcinomas that have small percentages of mucin have mammographic and histologic characteristics of more aggressive, invasive ductal carcinomas.

Adenocarcinoma, Mucinous↗