Biomedical subjects

Gary R Cutter

Publications and source records attributed to Gary R Cutter.

25 records · Page 2Linked to original sources

PubMed2003

Optimization of technique factors for a silicon diode array full-field digital mammography system and comparison to screen-film mammography with matched average glandular dose.

Contrast-detail experiments were performed to optimize technique factors for the detection of low-contrast lesions using a silicon diode array full-field digital mammography (FFDM) system under the conditions of a matched average glandular dose (AGD) for different techniques. Optimization was performed for compressed breast thickness from 2 to 8 cm. FFDM results were compared to screen-film mammography (SFM) at each breast thickness. Four contrast-detail (CD) images were acquired on a SFM unit with optimal techniques at 2, 4, 6, and 8 cm breast thicknesses. The AGD for each breast thickness was calculated based on half-value layer (HVL) and entrance exposure measurements on the SFM unit. A computer algorithm was developed and used to determine FFDM beam current (mAs) that matched AGD between FFDM and SFM at each thickness, while varying target, filter, and peak kilovoltage (kVp) across the full range available for the FFDM unit. CD images were then acquired on FFDM for kVp values from 23-35 for a molybdenum-molybdenum (Mo-Mo), 23-40 for a molybdenum-rhodium (Mo-Rh), and 25-49 for a rhodium-rhodium (Rh-Rh) target-filter under the constraint of matching the AGD from screen-film for each breast thickness (2, 4, 6, and 8 cm). CD images were scored independently for SFM and each FFDM technique by six readers. CD scores were analyzed to assess trends as a function of target-filter and kVp and were compared to SFM at each breast thickness. For 2 cm thick breasts, optimal FFDM CD scores occurred at the lowest possible kVp setting for each target-filter, with significant decreases in FFDM CD scores as kVp was increased under the constraint of matched AGD. For 2 cm breasts, optimal FFDM CD scores were not significantly different from SFM CD scores. For 4-8 cm breasts, optimum FFDM CD scores were superior to SFM CD scores. For 4 cm breasts, FFDM CD scores decreased as kVp increased for each target-filter combination. For 6 cm breasts, CD scores decreased slightly as kVp increased for Mo-Mo, but did not change significantly as a function of kVp for either Mo-Rh or Rh-Rh. For 8 cm breasts, Rh/Rh FFDM CD scores were superior to other target-filter combinations and increased significantly as kVp increased. These results indicate that low-contrast lesion detection was optimized for FFDM by using a softer x-ray beam for thin breasts and a harder x-ray beam for thick breasts, when AGD was kept constant for a given breast thickness. Under this constraint, optimum low-contrast lesion detection with FFDM was superior to that for SFM for all but the thinnest breasts.

Equipment Failure Analysis↗

PubMed2002

Performance of diagnostic mammography for women with signs or symptoms of breast cancer.

BACKGROUND: The performance of diagnostic mammography for women with signs or symptoms of breast cancer has not been well studied. We evaluated whether age, breast density, self-reported breast lump, and previous mammography influence the performance of diagnostic mammography. METHODS: From January 1996 through March 1998, prospective diagnostic mammography data from women aged 25-89 years with no previous breast cancer were linked to cancer outcomes data in six mammography registries participating in the Breast Cancer Surveillance Consortium. We used the final mammographic assessment at the end of the imaging work-up to determine abnormal mammographic examination rate, positive predictive value (PPV), sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve. We used age, breast density, prior mammogram, and self-reported breast lump jointly as predictors of performance. All statistical tests were two-sided. RESULTS: Of 41 427 diagnostic mammograms, 6279 (15.2%) were judged abnormal. The overall PPV was 21.8%, sensitivity was 85.8%, and specificity was 87.7%. Multivariate analysis showed that sensitivity and specificity generally declined as breast density increased (P =.007 and P<.001, respectively), that previous mammography decreased sensitivity (odds ratio [OR] = 0.52, 95% confidence interval [CI] = 0.36 to 0.74; P<.001) but increased specificity (OR = 1.43, 95% CI = 1.31 to 1.57; P<.001), and that a self-reported breast lump increased sensitivity (OR = 1.64, 95% CI = 1.13 to 2.38; P =.013) but decreased specificity (OR = 0.54, 95% CI = 0.49 to 0.59; P<.001). ROC analysis showed that higher breast density and previous mammography were negatively related to accuracy (P<.001 for both). CONCLUSIONS: Diagnostic mammography in women with signs or symptoms of breast cancer shows higher sensitivity and lower specificity than screening mammography does. Higher breast density and previous mammographic examination appear to impair performance.

Adult↗

PubMed2002

Performance comparison of full-field digital mammography to screen-film mammography in clinical practice.

Results of acceptance testing 18 full-field digital mammography systems for clinical use and of conducting annual physics surveys of 38 screen-film mammography systems were compared in terms of exposure times, mean glandular breast doses, and image quality. These evaluations were made using the same test tools on all systems, with emphasis on assessing automatic exposure control performance and image quality on both digital and screen-film systems using clinical techniques. Survey results indicated that digital mammography systems performed similarly to screen-film systems in terms of exposure times and mean glandular doses for thin to intermediate breasts, but that digital mammography systems selected shorter exposure times and lower mean glandular doses for thicker breasts. For all breast thicknesses, digital mammography systems yielded mean contrast-detail scores higher than those for screen-film systems. For all breast thicknesses, the 18 digital mammography systems demonstrated less variance in terms of exposure times, mean glandular doses, and contrast-detail scores than did the 38 screen-film systems tested. These results indicate that the clinical use of digital mammography may generally improve image quality for equal or lower breast doses, while providing tighter control on exposures and image quality than screen-film mammography.

Biophysical Phenomena↗

PubMed2002

Clinical comparison of full-field digital mammography and screen-film mammography for detection of breast cancer.

OBJECTIVE: The purpose of this work is to compare full-field digital mammography and screen-film mammography for the detection of breast cancer in a screening population. SUBJECTS AND METHODS: Full-field digital mammography was performed in addition to screen-film mammography in 6736 examinations of women 40 years old and older presenting for screening mammography at either of two institutions. Two views of each breast were acquired with each technique. The digital and screen-film mammograms were each interpreted independently. In addition to a clinical assessment, each finding was assigned a probability of malignancy for use in receiver operating characteristic analysis. In cases in which the digital and screen-film interpretations differed, a side-by-side analysis was performed to determine the reasons for the discrepancy. With few exceptions, findings detected on either technique were evaluated with additional imaging and, if warranted, biopsy. RESULTS: Additional evaluation was recommended on at least one technique in 1467 cases. These additional evaluations led to 181 biopsies and the detection of 42 cancers. Nine cancers were detected only on digital mammography, 15 were detected only on screen-film mammography, and 18 were detected on both. The difference in cancer detection is not statistically significant (p > 0.1). Digital mammography resulted in fewer recalls than did screenfilm mammography (799 vs 1007, p < 0.001). The difference between the receiver operating characteristic curve area for digital (0.74) and screen-film (0.80) mammography was not significant (p > 0.1). Reasons for discrepant interpretations of cancer were approximately equally distributed among those relating to lesion conspicuity, lesion appearance, and interpretation. CONCLUSION: No significant difference in cancer detection was observed between digital mammography and screen-film mammography. Digital mammography resulted in fewer recalls than did screen-film mammography.

Adult↗

PubMedDate not supplied

Impact of customized videotape education on quality of life in patients with chronic obstructive pulmonary disease.

PURPOSE: To compare the impact of a library of pulmonary rehabilitation videotapes versus an older videotape and usual care on quality of life and ability to perform activities of daily living in persons with chronic obstructive pulmonary disease. METHODS: Two hundred fourteen patients diagnosed with chronic obstructive pulmonary disease, emphysema, or chronic bronchitis were recruited and randomized to receive customized videotapes, standard videotapes, or usual care. Outcome measures included the Fatigue Impact Scale, Seattle Obstructive Lung Disease Questionnaire, and the SF-36(R) Health Survey. RESULTS: Differences in coping skills and emotional functioning on the Seattle Obstructive Lung Disease Questionnaire were found among the 174 subjects who completed the study. The customized videotape group improved by 8.6 and 4.8 points, respectively, whereas the score of the other groups decreased by less than 1 point for the coping skills, and the scores of the standard video and the control groups decreased by 3.0 and 2.1 points, respectively, for emotional functioning (P < .05, all comparisons). The scores using the Fatigue Impact Scale also improved for the customized videotape group, whereas the scores of the others remained unchanged. Videotape users demonstrated better conversion to and retention of exercise habits, with over 80% of customized videotape subjects who reported exercise habits at baseline continuing the habits as compared with 40% in the usual care group. Sedentary subjects at baseline were more likely to begin and maintain exercise if randomized to videotapes. CONCLUSIONS: These findings demonstrate increased quality of life, lower fatigue, and better compliance with a prescribed exercise regimen among subjects using the customized videotapes. There was a significant improvement in emotional functioning and coping skills among customized videotape subjects.

Activities of Daily Living↗

PubMedDate not supplied

Radiologist uncertainty and the interpretation of screening.

OBJECTIVE: To determine radiologists' reactions to uncertainty when interpreting mammography and the extent to which radiologist uncertainty explains variability in interpretive performance. METHODS: The authors used a mailed survey to assess demographic and clinical characteristics of radiologists and reactions to uncertainty associated with practice. Responses were linked to radiologists' actual interpretive performance data obtained from 3 regionally located mammography registries. RESULTS: More than 180 radiologists were eligible to participate, and 139 consented for a response rate of 76.8%. Radiologist gender, more years interpreting, and higher volume were associated with lower uncertainty scores. Positive predictive value, recall rates, and specificity were more affected by reactions to uncertainty than sensitivity or negative predictive value; however, none of these relationships was statistically significant. CONCLUSION: Certain practice factors, such as gender and years of interpretive experience, affect uncertainty scores. Radiologists' reactions to uncertainty do not appear to affect interpretive performance.

Colorado↗

PubMedDate not supplied

Mammographers' perception of women's breast cancer risk.

OBJECTIVE: To understand mammographers' perception of individual women's breast cancer risk. MATERIALS AND METHODS: Radiologists interpreting screening mammography examinations completed a mailed survey consisting of questions pertaining to demographic and clinical practice characteristics, as well as 2 vignettes describing different risk profiles of women. Respondents were asked to estimate the probability of a breast cancer diagnosis in the next 5 years for each vignette. Vignette responses were plotted against mean recall rates in actual clinical practice. RESULTS: The survey was returned by 77% of eligible radiologists. Ninety-three percent of radiologists overestimated risk in the vignette involving a 70-year-old woman; 96% overestimated risk in the vignette involving a 41-year-old woman. Radiologists who more accurately estimated breast cancer risk were younger, worked full-time, were affiliated with an academic medical center, had fellowship training, had fewer than 10 years experience interpreting mammograms, and worked more than 40% of the time in breast imaging. However, only age was statistically significant. No association was found between radiologists' risk estimate and their recall rate. CONCLUSION: U.S. radiologists have a heightened perception of breast cancer risk.

Adult↗