Biomedical subjects

N DeBruhl

Publications and source records attributed to N DeBruhl.

5 recordsLinked to original sources

PubMed2001

Volume-localized two-dimensional correlated magnetic resonance spectroscopy of human breast cancer.

A localized 2D correlation spectroscopic sequence (L-COSY) was implemented and applied in human breast cancer in vivo to evaluate the water to fat (both saturated and unsaturated) ratios and also to identify choline. Being in agreement with the conventional 1D magnetic resonance spectroscopy (MRS) results, elevated water to lipids ratios were found in breast cancers and choline was observed only in a few cancer patients.

Adult↗

PubMed1997

Effects of ambient light and view box luminance on the detection of calcifications in mammography.

OBJECTIVE: Viewing conditions can affect diagnostic performance differently depending on background optical densities. We quantified detection accuracy when viewing calcifications in glandular tissue under recommended viewing conditions versus accuracy with lower view box luminance and higher ambient lighting. MATERIALS AND METHODS: A phantom with adipose, 50% adipose and 50% glandular, and glandular-simulating material was imaged, and images were interpreted by five medical imaging physicists using two lighting conditions: the recommended one, high view box luminance (4365 nits) with low ambient light (25 lx), and a suboptimal one, low view box luminance (1763 nits) with moderate ambient lighting (290 lx). Then, a dense (Breast Imaging Reporting and Data System breast composition pattern type 4) unfixed cadaveric breast with numerous native calcifications was imaged 28 times. Nineteen of the films had added clusters of simulated calcifications. Three radiology fellows, each with 11 months of training in mammography, identified the added calcification clusters in the images under the two lighting conditions. Changes in phantom analysis and accuracy of the clinical diagnosis were compared for each lighting condition. RESULTS: On mammograms of the phantom, both speck and fibril identification were degraded by an average of 1.4 objects for the adipose-simulating section (with its darker optical density). For medium optical densities, found in the section with the simulation of 50% glandular and 50% adipose tissue, suboptimal lighting conditions had little or no effect on speck and fibril identification. For sections of the phantom that simulated glandular tissue, an average of 0.6 specks or fibers were not seen when lighting was suboptimal. With the dense cadaveric breast, the fraction of added calcification clusters detected by the three observers improved by an average of 17% when low luminance viewers and high ambient light were replaced with recommended viewing conditions; individual scores of the observers improved significantly: p values ranged from .02 to .05. CONCLUSION: Luminance of the view box and ambient lighting significantly affect detection of calcifications in dense breasts when images are interpreted by radiologists with about 1 year of training in mammography. Detection of calcifications in phantoms is primarily degraded for adipose tissue with its darker optical density. However, when lighting conditions are suboptimal, some observers also have trouble detecting calcifications in glandular tissue with its low optical density.

Adipose Tissue↗

PubMed1994

Mammography quality assurance from A to Z.

Quality assurance (QA) refers to all planned, systematic activities that instill confidence that quality mammography is being performed. Quality control (QC) refers only to the technical aspects of the examination. Standardized labeling of mammograms and the format for mammographic reports are important parts of a QA program; recommendations for both have been published by the American College of Radiology. Minimum staff for a mammography service consists of a scheduler, technologist(s), medical physicist, and radiologist. The scheduler asks the patient questions to ensure that the appropriate examination is performed, gives the patient instructions, and asks the patient to complete a history questionnaire including a release form to obtain earlier mammograms. One certified, licensed technologist is designated to perform QC, which includes maintaining darkroom, screen, and view box cleanliness; reviewing processor performance, checked with sensitometer, densitometer, and phantom images; repeat analysis; analysis of fixative retained in film, darkroom fog, screen-film contact, and adequacy of compression; and visual inspection of equipment. A certified medical physicist performs equipment acceptance testing and annual QC visits thereafter. The radiologist oversees all aspects of the QA program, including selecting and regularly observing the technologists, selecting and meeting with the physicist, communicating results, ensuring patient follow-up, and assessing patient outcome data. The radiologist is ultimately responsible for image quality and the standard of patient care.

Biopsy↗

PubMed1994

Mammograms obtained with rhodium vs molybdenum anodes: contrast and dose differences.

OBJECTIVE: A mammography unit with both a molybdenum anode and a rhodium anode, filtered with molybdenum and rhodium, respectively, was evaluated to determine which types of women would benefit from the dose savings of the rhodium combination despite some loss of contrast. SUBJECTS AND MATERIALS: In 100 women, the molybdenum anode and molybdenum filtration (Mo/Mo) were used to obtain mammograms of the right breast, and the rhodium anode and rhodium filtration (Rh/Rh) were used for mammograms of the left breast. All mammograms were obtained at 26 kVp. All milliampere-second values used to radiograph the breasts of these women were recorded. Mammograms of 54 women (30 with previous mammograms available), representing the four types of breasts as defined by the American College of Radiology, were interpreted by three radiologists. Each mammogram was assigned a grade for breast type, preference (Rh/Rh, Mo/Mo, or previous mammograms), contrast, and sharpness. RESULTS: Overall, mammograms obtained by using the Mo/Mo combination were preferred. However, for images of types 3 and 4 breasts, Rh/Rh was preferred twice as often as it had been for mammograms of types 1 and 2 breasts. The mean glandular dose for all breast types when the Rh/Rh combination was used was 42% of the dose used for the Mo/Mo combination. For a 6-cm-thick dense breast, the Rh/Rh combination required 40% of the dose required for the Mo/Mo combination. CONCLUSION: Mammograms obtained with the Rh/Rh combination carried an overall decrease in contrast and mean glandular dose. However, for young women and some women with large dense breasts, the Rh/Rh mammograms were equivalent to or better than the mammograms obtained with the Mo/Mo combination. Effective use of Rh/Rh units requires careful selection of women based on age or the amount of glandular tissue seen on previous mammograms.

Breast↗

PubMed1993

Mammographic positioning: evaluation from the view box.

To evaluate the quality of breast positioning for mediolateral oblique (MLO) and craniocaudal (CC) views, a prospective study of 1,000 consecutive bilateral screening mammographic examinations was performed. Six criteria were tested, including depth of tissue seen, inferior extent of the pectoral muscle relative to the posterior nipple line, presence of fibroglandular tissue at the posterior edge of the film, and whether the nipple was in profile. Pectoral muscle was depicted to within 1 cm of the nipple line or below it on 1,612 of the 2,000 MLO mammograms (81%); all fibroglandular tissue was depicted on 1,532 MLO mammograms (77%). The depth of tissue depicted on the CC mammogram was within 1 cm greater or less than the depth on the MLO mammogram on 1,586 CC mammograms (79%); the pectoral muscle was seen on 646 CC mammograms (32%). The nipple was in profile in 1,769 MLO mammograms (88%) and 1,783 CC mammograms (89%) but not in profile in either view in 83 cases (4%). Overall improvement was seen in 400 of 587 examinations (68%) when new mammograms were compared with previous mammograms. These criteria can be used to evaluate positioning performance and for quality control.

Female↗