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Biomedical subjects

K A Shaffer

Publications and source records attributed to K A Shaffer.

At least 37 records · Page 2Linked to original sources

How U.S. radiologists use their professional time: factors that affect work activity and retirement plans.

PURPOSE: To determine what demographic, professional, and practice characteristics are related to the amount of time radiologists work per week, to their allocation of time among professional activities, and to their plans for retirement. MATERIALS AND METHODS: The American College of Radiology surveyed 2,804 radiologists and nuclear medicine specialists. Means and percentiles were calculated for the radiologists' number of hours and days worked per week, number of weeks away, percentage allocation of time, and retirement intentions. Multiple linear and logistic regression analyses were performed. RESULTS: Full-time, post-training radiologists worked a mean of 50 hours per week. Radiologists spent 2 weeks on professional education and 4.4 weeks on vacation each year. On average, 68% of professional time was spent on hospital patient care; 18%, on office patient care; 7%, on teaching and research; and 5% on administration. Forty-one percent of radiologists planned to eventually work part-time; 47% intended to retire fully. CONCLUSION: These data will provide an important baseline for modeling the future size of the radiologist workforce and for assessing changes in the ways radiologists use their time and plan their futures.

Adult↗

U.S. radiologists' satisfaction in their profession.

PURPOSE: To determine characteristics associated with differences among radiologists in professional satisfaction and the effect of satisfaction on career plans. MATERIALS AND METHODS: The American College of Radiology surveyed 2,804 radiologists and nuclear medicine specialists in the United States. Single-variable and multivariate analyses were performed. RESULTS: Sixty-five percent of radiologists were currently satisfied with their profession; 31% were more satisfied than they were 5 years ago, 32% felt the same, and 37% were less satisfied. Current satisfaction was most likely for radiologists with a diagnostic radiology subspecialty, board certification, age over 45 years, an academic practice, a salaried position, a full-time practice, urban location, and location in the West. Professional satisfaction relative to that 5 years ago was particularly high for (among others) young radiologists. Poorly satisfied radiologists were more likely to plan a career change and eventual part-time work. Female radiologists were as satisfied as males. CONCLUSION: This study identifies sources of radiologists satisfaction and dissatisfaction and effects of satisfaction on career plans.

Adult↗

The sex ratio of American radiologists: comparison and implications by age, subspecialty, and type of practice.

OBJECTIVE: The purpose of this paper is to present results related to two questions regarding changes in the sex ratio of American radiologists. Do men and women in radiology have different patterns of subspecialization, postresidency training, board certification, or practice characteristics? Do differences in patterns between the sexes imply that the number of radiologists required in the future will change with a changing sex ratio of radiologists? MATERIALS AND METHODS: A survey questionnaire was mailed to a stratified random sample of 2804 radiologists, radiation oncologists, and nuclear medicine specialists drawn from the American Medical Association Physician Masterfile. The survey achieved a response rate of 69%. Stratification criteria included sex, age, and subspecialty. The survey questions included age, sex, subspecialty, training status, board certification, type of practice, principal work activity, source of income, hours worked, and amount of time away from the practice. Data analysis used descriptive statistics, ordinary least squares regression, and logit analysis. Weighting assured that results represent all radiologists. RESULTS: Only 13% of active radiologists who have finished training are women. The percentage varies with age; 6% of radiologists 45 years old or older; 22% of those 35-44 years old, and 23% of those younger than 35 years old were women. Differences in the sex ratio were not associated with differences in board certification or postresidency fellowships, but subspecialization differed by sex. Women were more likely than men to be salaried, to work part-time, to be engaged in teaching, and to work in an office rather than in a hospital. Differences in the sex ratio had little impact on estimates of the number of radiologists that will be needed in the future. CONCLUSION: Female radiologists have subspecialization and practice characteristics different from those of male radiologists. The increasing percentage of women in the profession will have little effect on the number of radiologists and radiation oncologists needed.

Adult↗

Radiologists in the United States: demographic, professional, and practice characteristics.

OBJECTIVE: The purpose of this report is to present a statistical portrait of radiologists in the United States based on the 1990 American College of Radiology Manpower Survey. Unlike previous surveys, this survey included radiologists who were not members of the College and was thus more representative of all radiologists. (Approximately three quarters of radiologists are College members.) We examined how the demographic, professional, and practice characteristics of radiologists vary among major groups within the profession. MATERIALS AND METHODS: A stratified random sample of 2804 radiologists and nuclear medicine specialists was drawn from the American Medical Association Physician Masterfile, which is the most complete and extensive single source of information on physicians in the United States. Because the total numbers of female radiologists, nuclear medicine specialists, and radiologists less than 35 years old are relatively small, these groups were deliberately "oversampled" (hence the term stratified random sample) to ensure sufficient numbers of responses in these categories for meaningful analysis. A total of 1845 completed questionnaires were received, which yields a response rate of 68% if the questionnaires sent to invalid addresses are excluded. Responses were weighted to make the data representative of all radiologists, despite differences in sampling rates. RESULTS: Findings for professionally active radiologists who completed their training included the following: 94% were certified by the American Board of Radiology, 13% were women, 47% were less than 45 years old, fees for service were the primary remuneration for 62%, and 72% are in practices owned by physician members of the practice. By major activity in radiology, 69% were diagnostic radiology generalists; 11% were radiation oncologists; 18% were diagnostic radiology subspecialists; and 2% were nuclear medicine specialists. A breakdown by age indicated that the age group of radiologists less than 45 years old included more women, diagnostic subspecialists, and persons who had fellowship training than other age groups did. Percentages of diagnostic radiology generalists and solo practitioners were lower among younger radiologists. Radiation oncologists, compared with all others, were the most likely to practice solo or in small groups of two to four members. The subfields with the highest percentages (60% or more) of diagnostic radiologists reporting expertise or proficiency were CT, mammography, and sonography. Among radiologists who were retired, half had retired by the time they were 65 years old. However, a majority of radiologists 65-69 years old were still working, as were 40% of those 70-74 years old. CONCLUSION: The profession of radiology is changing, with more women, subspecialists, and fellowship-trained radiologists in younger age groups and fewer solo practitioners. Only a small percentage of radiologists are not board certified. Radiologists typically remain professionally active into their late 60s or even beyond.

Adult↗

Imaging of regional spread of breast cancer by internal mammary lymphoscintigraphy, CT, and MRI.

Forty women with breast cancer underwent imaging by internal mammary lymphoscintigraphy (IMLS), which was correlated with the results of CT and MRI of the chest. IMLS was performed and interpreted using the previously described methods of Ege. It identified 22 instances of ipsilateral internal mammary nodal involvement, none of which corresponded to cases of abnormally enlarged (diameter greater than 1.0 cm) internal mammary nodes on CT and/or MRI. Positive IMLS was associated with axillary nodal metastases in 15 out of 22 instances. The authors conclude that IMLS provides information on regional nodal spread of breast cancer that is not available with either CT/MRI imaging or axillary biopsy.

Antimony↗

MR detection of tumor in the internal auditory canal.

The MR appearance of 15 tumors within or near the internal auditory canal was analyzed in detail and compared with the subsequent surgical observations. In most cases, nonenhanced MR showed the precise extent of the intracanalicular and extracanalicular tumor despite minor variations in appearance. In a case of facial nerve neurinoma, the extent to which the tumor invaded the canal was underestimated by MR. Gadolinium-DTPA enhancement is expected to eliminate uncertainties in MR imaging of the internal auditory canal.

Cerebellar Neoplasms↗

Surface-coil magnetic resonance imaging of the internal auditory canal.

Computed tomography is effective for detecting acoustic neuromas, but not for resolving individual nerves in the internal auditory canal. Surface-coil magnetic resonance (MR) images of the internal auditory canal were obtained using a 1.5 T superconducting magnet, a 13.5-cm-diameter surface coil, 3- and 5-mm-thick slices, and partial-saturation pulse sequences. Cranial nerves VII and VIII (three branches) were identified on MR images in volunteers and on corresponding cryomicrotomic sections. The nerves were obscured in one patient with an acoustic neuroma. Because high-resolution surface-coil images can demonstrate specific nerves in the internal auditory canal, MR should be a sensitive study to evaluate cranial nerves VII and VIII in patients with facial paralysis and neurosensory hearing loss that is congenital or caused by small acoustic neuromas.

Facial Nerve↗

Magnetic resonance imaging of the internal auditory canal.

Three patients with exclusively or predominantly intracanalicular neuromas and 5 with presumably normal internal auditory canals were examined with prototype 1.4- or 1.5-tesla magnetic resonance (MR) scanners. MR images showed the 7th and 8th cranial nerves in the internal auditory canal. The intracanalicular neuromas had larger diameter and slightly greater signal strength than the nerves. Early results suggest that minimal enlargement of the nerves can be detected even in the internal auditory canal.

Facial Nerve↗

Comparison of computed tomography and complex motion tomography in the evaluation of cholesteatoma.

High-resolution axial and coronal computed tomographic (CT) scans were compared with coronal and sagittal complex motion tomograms in patients with suspected middle ear cholesteatomas. Information on CT scans equaled or exceeded that on conventional complex motion tomograms in 16 of 17 patients, and in 11 it provided additional information. Soft-tissue resolution was superior with CT. In 14 patients who underwent surgery, CT provided information that was valuable to the surgeon. On the basis of this study, high-resolution CT is recommended as the preferred method for evaluating most patients with cholesteatomas of the temporal bone.

Cholesteatoma↗

The potential value of liquid-crystal thermography in detecting significant mastopathy.

Liquid-crystal thermography (LCT) was assessed as a means of detecting proliferative disorders of the breast independently of other clinical or radiological data. There was no statistically significant difference between positive diagnosis rates for LCT of the breast in biopsy-proved proliferative disorders and in clinically and radiologically normal volunteers. While this experiment was not designed to evaluate LCT for detection or diagnosis of advanced, clinically occult, or minimal breast cancer, the data suggest that this technique can identify some large, bulky tumors, and that the smaller the lesion, the less likely that it would be detected by LCT.

Breast Neoplasms↗

Temporal bone: comparison of pluridirectional tomography and high resolution computed tomography.

The recent introduction of high resolution computed tomography (CT) capable of resolving delicate bony structures such as the temporal bone marks another significant advance in diagnostic imaging. This study was designed to compare the integrity of these new CT images, standard CT images, and conventional complex motion tomographic images against contact radiographs of sliced anatomic specimens. Temporal bones of three frozen cadaver heads were studied with complex motion tomograms at 1 mm intervals and contiguous CT scans at 1.5 mm intervals in axial, coronal, and sagittal projections. The heads were physically sectioned at 2 mm intervals in planes corresponding to the radiographic planes using a precise indexing and sawing system. The tomographic images were compared for information content to contact radiographs of the anatomic specimen sections. Conventional tomographic images and expanded number range target reconstruction CT images proved to be highly accurate. Standard CT reconstruction images were not. The probable clinical effectiveness of each method is discussed.

Cadaver↗

High resolution computed tomography of the temporal bone.

The radiation dose and the anatomic detail of computed tomography (CT) and conventional tomography were studied in 18 patients with suspected acoustic neuroma, cholesteatoma, malignant tumor, and temporal bone fracture. It is concluded that CT is the technique of choice in patients suspected of having acoustic neuromas or malignant tumors of the temporal bone, while hypocycloidal tomography should be used to evaluate pateints with otosclerosis, small cholesteatomas, and inflammatory disease of the middle ear. For diagnosing fractures and large cholesteatomas, CT and conventional tomography are complementary.

Cholesteatoma↗

Manipulation of CT data for temporal-bone imaging.

The usefulness of CT in studying the temporal bone is limited by spatial resolution and by the range of absorption coefficients which can be displayed. The authors evaluated the effect of four types of data manipulation: (a) reconstruction of data with different convolution filters (target reconstruction), (b) extension of the range of CT numbers, (c) mathematical filtration to enhance edges, and (d) correction for beam hardening. Target reconstruction and extension of the CT range significantly improved visualization of small structures in the temporal bone.

Humans↗

Thin section computed tomography of the temporal bone.

The applications of computed tomography (CT) in temporal bone studies have increased because of thin sections (less than 2 mm), high spatial resolution (less than 0.8 mm) and high resolution reconstruction algorithms. Thin section CT was performed in 56 patients suspected of having acoustic neuromas, other tumors, cholesteatomas or fractures. High resolution experimental image reconstruction was performed in some cases. In most cases, the pathologic process was demonstrated as well or better on CT scans than on complex motion tomograms. We concluded that high resolution, thin section CT is the technique of choice to evaluate patients with temporal bone tumors. CT is an effective means of studying patients with large cholesteatomas and fractures, although conventional tomography may be complementary in some cases. The value of CT in patients with otosclerosis and inflammatory disease of the middle ear should be evaluated more extensively.

Adult↗

Which breast to biopsy: an expanding dilemma.

To provide insight into the significance of findings reported from screening asymptomatic women for breast cancer, we reviewed 19,928 mammographic studies with the accompanying physical examination and correlated these findings with 554 breast biopsies. Of 83 breast biopsies with suspicious findings on both physical examination and mammography, 72 demonstrated breast cancer (87%). Of 155 biopsies for suspicious changes on mammography alone, 50 (32%) demonstrated breast cancer. The accuracy of suspicious mammography was independent of findings limited to physical examination, 34 (17%) had breast cancer; 31 were in 152 biopsies of patients with mammography interpreted as normal (20%) and three were in biopsies of 52 patients (6%) in whom a visualized mass was interpreted as benign. One hundred and twelve breast biopsies were performed for changes interpreted as normal or benign. Six malignancies were discovered (5%). No cancer was found in 31 biopsies for nonpalpable benign mammographic abnormalities. Our results emphasize the importance of discriminating between nonvisualization of a mass and mammographic recognition of either a benign or malignant tumor. The reliability of interpretation is considerably greater for a visualized lesion than a nonvisualized one.

Biopsy↗