Biomedical subjects

L W Bassett

Publications and source records attributed to L W Bassett.

At least 19 recordsLinked to original sources

PubMed1992

Effect of poor control of film processors on mammographic image quality.

With the increasingly stringent standards of image quality in mammography, film processor quality control is especially important. Current methods are not sufficient for ensuring good processing. The authors used a sensitometer and densitometer system to evaluate the performance of 22 processors at 16 mammographic facilities. Standard sensitometric values of two films were established, and processor performance was assessed for variations from these standards. Developer chemistry of each processor was analyzed and correlated with its sensitometric values. Ten processors were retested, and nine were found to be out of calibration. The developer components of hydroquinone, sulfites, bromide, and alkalinity varied the most, and low concentrations of hydroquinone were associated with lower average gradients at two facilities. Use of the sensitometer and densitometer system helps identify out-of-calibration processors, but further study is needed to correlate sensitometric values with developer component values. The authors believe that present quality control would be improved if sensitometric or other tests could be used to identify developer components that are out of calibration.

Humans↗

PubMed1992

Enlarging fibroadenoma in a postmenopausal woman: case report.

The authors describe mammographic and pathologic evidence of the growth of a fibroadenoma in an 82-year-old obese woman, 44 years after menopause, who had never been treated with hormone therapy. The patient's obesity is hypothesized as the causal factor for increased estrogen levels leading to growth of the fibroadenoma.

Adenofibroma↗

PubMed1992

Silicone breast implants in vivo: MR imaging.

This study was designed to evaluate pulse sequences and patient positioning for MR imaging of silicone breast implants in patients. One hundred forty-three patients (281 silicone implants) underwent imaging over a 21-month period. The combination of a T2-weighted fast spin echo technique (SE), T2-weighted fast SE with water suppression, and T1-weighted SE with fat suppression is recommended to reliably differentiate silicone from other breast tissues and to identify intracapsular and extracapsular ruptures or leaks. Seventy of the 143 patients underwent removal of their silicone implants. The sensitivity for detection of silicone implant rupture was 76%, with a specificity of 97%. Positioning the patient prone improved image quality.

Adult↗

PubMed1992

Strategies for implementation and quality assurance for mammographic screening.

Compliance with screening mammography guidelines is affected by complex factors, including cost, accessibility, education, and attitudes of referring physicians. High-volume mammography facilities have lower fees and higher quality. Quality assurance is the focus of the voluntary American College of Radiology Mammography Accreditation Program, and over half of all mammography units are accredited. Nonetheless, pressure for mandatory quality standards is increasing. Mobile mammography reduces costs and increases access, but it presents challenges in financing and quality assurance. These screening issues, especially quality assurance, are not taught adequately in radiology residency training programs. Yet public awareness of the benefits of early detection has resulted in more lawsuits for failure to diagnose and delay in diagnosis. Preventive measures reduce medicolegal risks. On a personal level, the psychologic trauma of screening mammography is greater than was previously suspected. However, associated anxiety and stress do not seem to affect compliance with screening guidelines adversely.

Female↗

PubMed1992

Mammographic analysis of calcifications.

Because mammographically detected calcifications are frequently the only sign of breast cancer, the breast radiography equipment, screen-film imaging package, and film processing should be optimized to detect such calcifications. For this purpose, dedicated units with molybdenum targets, microfocal spot magnification capability, reciprocating grids, and high output x-ray tubes are required. With the greater use of state-of-the-art mammography, intraductal carcinoma, or DCIS, manifested only by calcifications is being detected more frequently than ever. DCIS can be of the comedo, cribriform, or micropapillary types. Comedocarcinoma, characterized by linear and branching (casting) calcifications, is the most aggressive type, and it has the highest rate of recurrence after breast-conserving surgery. Cribriform and micropapillary calcifications are characteristically punctate and vary in size and shape. In addition to histologic type, the recurrence of DCIS is related to its extent at detection and whether adequate tissue was removed at the time of breast-conserving surgery. Biopsies for suspicious calcifications should be followed immediately by specimen radiography to verify their removal. If breast-conserving surgery is elected for DCIS, the resected segment of tissue should be examined with pathologic techniques designed to determine whether the margins are clear of tumor. For DCIS and invasive cancers with extensive intraductal component, microfocus magnification mammography over the surgical site is recommended prior to radiotherapy to identify any residual tumor calcifications. Although state-of-the-art mammography is very sensitive in the detection of calcifications, it is low in specificity, thus resulting in a large number of false-positive mammograms and a relatively low true-positive biopsy rate. While some benign calcifications cannot be distinguished from those of malignancy, the number of biopsies for benign conditions can be decreased by careful analysis of the mammograms in a search for features indicating benignity.

Breast Diseases↗

PubMed1991

Mammographically guided fine-needle aspiration biopsy of nonpalpable breast lesions. Can it replace open biopsy?

The authors report the accuracy of mammographically guided fine-needle aspiration (FNA) for the diagnosis of nonpalpable breast lesions in a series of 71 patients. Each mammographically guided FNA was immediately followed by hookwire localization and open biopsy. Seven malignancies were identified cytologically, but three cancers were not detected in aspirates judged to be sufficient for diagnosis. In addition, 19 aspirates were reported to be insufficient, and 4 of these were obtained from lesions histologically proven to be adenocarcinoma. Although no false-positive diagnoses were encountered, the technique demonstrated a sensitivity of 78% and a diagnostic accuracy of 94% for adequate specimens. In this study, mammographically guided FNA was insufficiently sensitive to replace open biopsy for the diagnosis of nonpalpable breast lesions.

Biopsy↗

PubMed1991

Anatomy of the hip: correlation of coronal and sagittal cadaver cryomicrosections with magnetic resonance images.

Magnetic resonance imaging (MRI) is noninvasive and provides images with higher soft tissue contrast than possible with any other imaging modality. Unlike CT which depicts anatomy in the axial plane, MRI is capable of producing images in thin cross sections acquired directly in any plane, usually axial, coronal or sagittal planes. The use of diagnostic MR images is facilitated by an understanding of the detailed anatomy that is depicted. The purpose of this study was to identify anatomical structures in coronal and sagittal cryomicrosections of the hip region. Thin cryosections of the hips of fresh-frozen cadavers were obtained by a method developed by one of the authors (WR). These sections were matched with thin-section, high resolution MR images of a normal volunteer. The complex anatomy of the hip and its surrounding muscles, tendons and ligaments was exquisitely depicted on both the cadaver microcryosections and the matched MRT images.

Cadaver↗

PubMed1991

Increased radiation dose at mammography due to prolonged exposure, delayed processing, and increased film darkening.

Four single-emulsion films introduced over the past 2 years--Du Pont Microvision, Fuji MiMa, Konica CM, and Eastman Kodak OM--were compared with Eastman Kodak OM SO-177 (Min-RE) film to evaluate their varying effects on mean glandular dose of reciprocity law failure due to prolonged exposure, delayed processing, and increased film darkening as a result of increased radiation exposure to improve penetration of glandular tissue. Exposures over 1.3 seconds led to increased radiation doses of 20%-30%. Delays in processing of 6 hours decreased processing speed by 11%-32% for all films except Du Pont Microvision. Optical density increases of 0.40 required 20%-30% more skin exposure for all five films. Optimal viewing densities were also evaluated and found to be different for each of the five films. Mammographers need to be aware of these differences in mammographic films to achieve maximum contrast at mammography.

Breast↗

PubMed1991

Usefulness of mammography and sonography in women less than 35 years of age.

Indications, clinical history, mammographic findings, and clinical outcome were reviewed in 1,016 women younger than 35 years who underwent mammography during an 8-year period. The indications for mammography were a palpable mass in 454 (44.7%), findings at routine screening in 237 (23.3%), lumpiness in 29 (14.9%), unilateral nipple discharge in seven (3.5%), localized breast tenderness in six (5.1%), adenopathy in three (1.9%), diffuse tenderness in two (2.9%), bilateral nipple discharge in two (1.5%), and miscellaneous in four (2.2%). In 405 women (39.9%), at least two-thirds of the breast tissue was radiodense; however, in 299 (29.4%) women the breast was predominantly fatty, allowing for excellent mammograms. Six women had carcinomas: Mammographic findings prompted biopsy in one patient, indicated a benign-appearing mass (found to be solid at sonography or aspiration) in three patients with a palpable mass (contributing to delay in biopsy in two), and were negative in two. Sonography was performed in 389 women and was useful in preventing unnecessary biopsy of cysts but was not useful in differentiating benign from malignant solid masses. Younger women with persistent localized breast symptoms should undergo a tailored mammographic examination, but negative findings or findings of a benign lesion should not preclude biopsy of a palpable solid mass.

Adult↗

PubMed1991

Present status of residency training in mammography.

We conducted a telephone interview of all 207 accredited diagnostic radiology residency training programs listed in the American Medical Association's Directory of Graduate Medical Education Programs. Resident training in mammography was offered in 206 programs, and 35% of the programs had initiated this training within the past 3 years. Residents had an assigned block of time to do mammography in 84% of the programs. Of the 206 programs, 40% had rotations devoted exclusively to mammography, with 82% of the exclusive rotations lasting from 4 to 8 weeks. Residents were performing localization procedures in 91% of the programs and dictating cases in 81%. A distinction was made between screening and diagnostic examinations by 35% of the training institutions, at least in terms of the fee for the examination. Radiologists who devoted at least half of their practice to mammography taught in 52% of the programs. The American College of Radiology has granted accreditation in mammography to 29% of the programs. Although almost all accredited residency training programs offer training in mammography, there are some deficiencies in this training. More residents need to gain the experience of dictating mammography reports and need to learn about the distinctions between screening and diagnostic mammography. Despite the anticipated deluge of screening examinations in the next decade, there were only 17 fellowships that included at least 6 months of mammography identified in 15 (7%) of the institutions; only 11 of these were full-time 1-year breast imaging fellowships.

Curriculum↗

PubMed1991

Breast sonography.

Sonographic equipment for breast imaging has continued to improve, and the role of breast sonography has evolved to that of an indispensable adjunct to mammography. Breast sonography is not useful for screening for breast cancer in any age group. Its main use is for the differentiation of cystic vs solid palpable and mammographically visible masses. If strict sonographic criteria are used for a simple cyst, the diagnostic accuracy approaches 100%. Sonographic diagnosis of a simple cyst precludes the need for further workup, including aspiration, biopsy, or followup. This article emphasizes the technical aspects of breast sonography, especially those factors that alter the diagnostic information on the images. These factors can be especially problematic in differentiating cysts and solid masses, the most common diagnostic use of breast sonography. Selection of equipment depends largely on the requirements of a specific practice. Optimally, the sonographic equipment is located close to where mammography is performed, and the sonographic and mammographic findings are interpreted together.

Breast Neoplasms↗

PubMed1991

The prevalence of carcinoma in palpable vs impalpable, mammographically detected lesions.

Concern over excessive numbers of false-positive mammograms, leading to unnecessary investigations and surgical interventions, has been cited as a barrier to mammographic screening for breast cancer. We compared the biopsy results from palpable vs impalpable, mammographically detected lesions from one experienced breast surgeon's practice from July 1980 through July 1989. Overall, there were 372 biopsies in 346 women. Of 143 biopsies for palpable abnormalities, 48 (34%) yielded a primary malignant lesion. The length of the palpable cancers averaged 3.7 cm (median, 2.8 cm). Sixteen (33%) of the 48 biopsies were in patients who had positive axillary lymph nodes, and five (10%) were in patients who had distant metastases at the time of biopsy. Of 229 biopsies for impalpable, mammographically detected lesions, 72 (31%) yielded a primary breast carcinoma. Excluding 34 carcinomas that had only calcifications, the length of the mammographically detected tumors averaged 2.0 cm (median, 1.5 cm). Eleven (15%) of the 72 biopsies were in patients who had positive axillary nodes, and none were in patients who had distant metastases at the time of biopsy. The positive predictive values (number of cancers detected divided by the number of biopsies recommended) were not significantly different when comparing biopsies indicated for palpable, clinically detected (34%) vs impalpable, mammographically detected (31%) abnormalities (p = .669). However, the mammographically detected cancers were smaller, more often noninvasive (32% vs 4%), less often associated with axillary metastases (15% vs 33%), and without distant metastases (0% vs 10%).

Biopsy↗

PubMed1991

Diagnostic importance of the radiographic density of noncalcified breast masses: analysis of 91 lesions.

Radiographic density is considered an important feature in the evaluation of noncalcified breast masses, yet no studies assessing its value have been published. The radiographic densities of 91 biopsy-proved, nonfatty, noncalcified breast masses were evaluated by three mammographers. The density determinations made by each observer were compared with the histologic outcome for the 51 benign and 40 malignant lesions. With the kappa statistic, interobserver agreement was relatively poor (0.22 to 0.49), and intraobserver agreement for one expert mammographer was 0.50. When the majority opinion of the mammographers was used, sensitivity was 48%, specificity was 80%, and both positive and negative predictive values were 66%. As a solitary feature in lesion analysis, mammographic density is difficult to assess and is of limited value for the prediction of the benign or malignant nature of noncalcified breast masses.

Biopsy↗

PubMed1991

Preoperative evaluation of osteosarcoma: value of gadopentetate dimeglumine-enhanced MR imaging.

Decisions regarding the surgical approach in osteosarcoma require accurate assessment of tumor extent. In order to determine whether enhancement with gadopentetate dimeglumine could add clinically significant information to that available with unenhanced MR imaging, 21 patients with osteosarcoma underwent preoperative MR imaging. T1- and T2-weighted spin-echo MR images obtained before and after administration of IV gadopentetate dimeglumine were evaluated to determine the conspicuity of marrow and soft-tissue extent of tumor, including tumor involvement of major neurovascular bundles and adjacent joints. MR results were correlated with tumor margins found at surgery. In some instances, use of gadopentetate dimeglumine obscured differentiation of tumor from normal marrow or tumor infiltration into perineurovascular fat, and tumor extension through pseudocapsule could not be differentiated from peritumoral edema after contrast administration. Contrast enhancement did assist in differentiation of intraarticular tumor from effusion; however, synovial invasion could be identified on unenhanced T1-weighted images by loss of synovial fat and cortical disruption. These results indicate that gadopentetate dimeglumine does not assist in defining tumor margins of osteosarcoma.

Adolescent↗

PubMed1991

Nonspecific findings on MR imaging. The importance of correlative studies and clinical information.

Although magnetic resonance (MR) imaging is highly sensitive for the detection of abnormalities of the musculoskeletal system, changes in marrow and soft-tissue signal intensity are often nonspecific, and benign conditions may be mistaken for malignancy. In an effort to identify the cause of this type of misdiagnosis in MR examinations, the MR scans were reviewed of 30 patients whose images manifested bone and/or soft-tissue changes that were initially believed to be consistent with malignancy but were later found to represent benign conditions. Of the 30 patients, MR abnormalities were attributable to trauma in 11, benign tumors and tumorlike conditions in ten, infection in seven, and prior radiotherapy in two. In 24 cases, correlative imaging studies (14 patients), appropriate clinical history (six patients), and/or physical and laboratory examinations (four patients) would have avoided these misdiagnoses.

Adult↗

PubMed1991

Magnetic resonance imaging of the shoulder.

Magnetic resonance imaging is an effective means for evaluating the painful shoulder. It has been shown to display accurately pathology associated with impingement syndrome and is useful in the detection of tears of the glenoid labrum. The role of magnetic resonance imaging in evaluation of synovial pathology has not yet been defined. Additional work is needed in this area.

Humans↗

PubMed1991

Mammography and early breast cancer detection.

Screening mammography has been shown to reduce breast cancer mortality. Both film-screen mammography and xeromammography are highly sensitive and specific. Mammography accreditation programs assure physicians and patients that a facility provides mammography of the highest quality, using the lowest possible radiation dose. Mammographic signs of early cancer include a small mass, calcifications, architectural distortion and a neodensity. Dense tissue may result in a false-negative examination even when a cancer is palpable, with adverse effects if biopsy is delayed.

Adult↗

PubMed1991

Advances in imaging of rheumatoid arthritis.

Several new imaging modalities have been found useful in clinical evaluation of patients with rheumatoid arthritis (RA). Magnetic resonance (MR) imaging has proven to be an excellent noninvasive method to evaluate the spine, shoulder, hip, and knees; its use for the evaluation of smaller joints is still being investigated. In patients with RA, MR imaging has been used to evaluate cervical spine instability, rotator cuff tear, osteonecrosis, and osteomyelitis. Patients with RA may have advanced osteoporosis, predisposing to insufficiency fractures. This includes fractures associated with increased activity after hip or knee arthroplasty. Newer methods for measuring the degree of osteoporosis include single photon absorptiometry, dual photon absorptiometry, quantitative computed tomography (CT), and dual-energy projection radiography. It has not yet been determined which of these methods will be most widely used in the future, but quantitative CT and dual-energy projection radiography currently show the most promise. Ultrasonography provides an excellent noninvasive method for the diagnosis of popliteal cysts, and color Doppler sonography can differentiate cyst and popliteal aneurysm. As compared to radiography or conventional CT, high-resolution CT provides an improved method to detect the early changes of RA in the lung parenchyma.

Arthritis, Rheumatoid↗