Biomedical subjects
Publications and source records attributed to C R Merritt.
The history of diagnostic US is marked by a remarkable series of giant advances in technology that have had major impact on the clinical impact of sonography. As the twenty-first century begins, US is poised for additional major advances in performance and clinical impact. In the evaluation of a multitude of diseases these developments will bring improvements in screening, diagnosis, and management and extend the value of US to a greatly expanded population.
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The approach outlined above for describing and reporting sonographic features of breast masses represents only the initial step in the development of a comprehensive system to enhance the accurate identification, reporting, and analysis of sonographic abnormalities of the breast. Future revisions, with validation of interobserver consistency in application of these descriptors across multiple centers, with feedback from potential users in the breast imaging community, will undoubtedly expand the utility of this effort.
PURPOSE: Because of the increasing use of sonography to rule out cancer in women with palpable breast abnormalities, this study was performed to determine the rate of sonographically occult malignancy in this clinical setting. METHODS: Women who were recommended for biopsy based on mammographic and/or clinical findings underwent breast sonography. This study retrospectively analyzed the subset of patients with palpable malignant lesions. Lesions were classified as visible or occult on mammography and sonography. Patients without a tissue diagnosis of tumor were excluded. RESULTS: Of 1,346 masses that underwent biopsy or aspiration, 616 lesions were palpable, and of these, 293 were malignant. Sonography detected all 293 palpable malignant lesions (95% confidence interval for sensitivity, 99-100%). Eighteen lesions were mammographically occult. The median lesion size as determined by sonography was 1.8 cm; for the lesions that were mammographically occult, the median size was 1.6 cm. The most common histopathologic diagnosis for both groups of lesions was infiltrating ductal carcinoma. CONCLUSIONS: All palpable malignant breast lesions were visible by sonography in patients in whom a biopsy was recommended. However, we caution that until the false-negative rate of sonography for equivocal palpable abnormalities is determined prospectively, sonography cannot be accurately applied to rule out malignancy in this setting.
In 1997, the American Board of Radiology (ABR) determined to develop a computer-based examination and to create a test center for administration of computer-based examinations. In implementation of its plan, the Board has developed a flexible examination platform, well-adapted to the graphics needs of an image-based examination, and at the same time, compatible with test centers being developed by other medical specialty boards in terms of hardware, software, and candidate surroundings. A test center for secure proctored examination of up to 33 candidates has been created at the Board's headquarters in Tucson, AZ. The decision of the ABR to employ computer-based testing as a part of its recertification process represents an important step of significance to the entire field of radiology, embracing methods that are rapidly becoming integral to the practice of radiology in the acquisition, display, and management of diagnostic imaging information.
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PURPOSE: To determine the extent to which emergency medicine physicians have assumed responsibility for performing and interpreting ultrasonographic (US) studies in emergency departments (EDs) in the United States. MATERIALS AND METHODS: The national 1997 Medicare Part B database was searched by using standard US procedure codes, location codes, and physician specialty codes. The authors determined how many US studies were performed in EDs and what percentage of those studies were performed by emergency medicine physicians, radiologists, or other physicians. RESULTS: During 1997, 234,820 ED US studies within nine major examination categories were performed in Medicare patients nationwide. Emergency medicine physicians performed 1,551 (0.7%) of these studies. When echocardiographic examinations were excluded, emergency medicine physicians performed 458 (0.2%) of the remaining total of 196,158 studies. CONCLUSION: Although emergency medicine physicians have claimed to be actively involved in ED US on a broad scale, the data reveal that their involvement in 1997 was minimal. This raises doubt as to whether they can properly train their residents to perform US or maintain their own competence at acceptable levels.
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A variety of cystic abdominal masses not related to the genitourinary tract may be encountered in the pediatric population. Ultrasound is the most informative imaging modality in the workup of these masses which include lymphangiomas, duplication cysts, enteric cysts, mesothelial cysts, pseudocysts, choledochal cysts, and gastrointestinal teratomas. The clinical and sonographic characteristics of these lesions are presented.
STUDY DESIGN: Records of 1,582 conventional and computed radiographic examinations performed to evaluate scoliosis were reviewed and compared to determine differences in total radiation burden. OBJECTIVE: This study evaluated the impact of computed radiographic imaging (CRI) on radiation exposure in children undergoing serial spinal radiographs for scoliosis assessment and compared exposure from CRI with that of low-dose film-screen combinations. SUMMARY OF BACKGROUND DATA: CRI permits diagnostic radiographic studies to be performed with a dose reduction of 80%-95% compared to conventional film-screen systems. High speed film-screen systems also permit a significantly lower exposure. Each approach has unique advantages and disadvantages. METHODS: Over 6 years, we performed 1,582 spinal examinations in children 4-14 years old using reduced dosage techniques with computed radiography. The images were obtained with Fuji FCR 101 and Philips PCR/SP systems. The adequacy of diagnostic image quality in the serial evaluation of scoliosis at different exposure levels was evaluated and compared with regular and film-screen systems with speeds ranging from 250 to 1,200. RESULTS: Diagnostic-quality images for evaluating scoliosis can be obtained with doses of 5% or less than required with conventional film-screen systems. Computed radiography provides image quality and dose reduction comparable to a 1,200-speed film-screen system. CONCLUSION: CRI gives satisfactory images at 5% reduction of the standard film-screen dose. Based on comparison with a 1,200 speed film-screen system, CRI provides equal or better image quality at a similar radiation dose. The cost of CRI is higher than for film-screen radiography, but wide latitude and the ability to tailor dose with requirements for image quality are significant advantages for CRI.
Doppler color flow imaging has been used to identify obstruction, rejection, and nonfunctioning renal allografts. When done in the immediate posttransplant period on poorly functioning kidneys, it allows early and accurate detection of surgically correctable changes such as arterial or venous thrombosis or early obstruction by blood, urine, or lymph. Further, it determines changes in intrarenal flow patterns that may indicate early transplant dysfunction, such as acute tubular necrosis and/or acute rejection as well as obstruction. Additionally, baseline values can be obtained in uncomplicated cases for serial follow-up. Between July 1980 and February 1991, 20 transplant patients had Doppler color flow imaging in the immediate posttransplant period. The kidney contour, perirenal collections, vessel flow patterns, and resistive indexes were assessed. In two patients, immediate surgical intervention salvaged the allograft. In several other patients with primary nonfunctioning kidneys, the study distinguished between acute tubular necrosis and obstruction due to external compression. We concluded that protocol Doppler color flow imaging is valuable in the immediate posttransplant period for determining surgically correctable complications.
Chorionic villus sampling is an exciting addition to prenatal diagnosis. With this procedure, accomplished quickly and with minimal discomfort at 9 to 11 weeks of pregnancy, information can be obtained about the fetal chromosomal complement. In addition, the fetus can be tested for a variety of disorders, such as sickle-cell disease, Tay-Sachs, and cystic fibrosis. The majority of fetal studies are normal, and such early prenatal testing provides relief of anxiety and opportunity for early maternal-fetal bonding.
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Fine needle aspiration (FNA) biopsy in conjunction with ultrasonic definition of nonpalpable masses in the neck region is being used more frequently. Currently available preoperative localization tests have failed, in many instances, to delineate adequately the location of missed adenomas of the parathyroid gland. We describe herein the use of ultrasonically guided FNA of parathyroid tissue with immunoperoxidase confirmation for precise localization of the diseased gland. Three patients with persistent hypercalcemia after exploration of the neck were referred to Ochsner Clinic, New Orleans. In two of these patients, a parathyroid adenoma had been removed, while in one patient no adenoma was found. All patients had elevated calcium (range 10.9 to 11.6 milligrams per deciliter), low phosphorous and elevated parathyroid levels. Preoperative ultrasonography to localize the suspected parathyroid glands was performed, with FNA and immunohistochemical confirmation. Smears confirmed adequate cellular material. Alcohol fixed, Papanicolaou stained and air dried, Wright's and Giemsa stained smears were evaluated for the presence of parathyroid cells by conventional cytologic examination. The Papanicolaou-stained slides were then decolorized in 1 percent hydrochloric acid in 70 percent ethanol. After decolorization, the smears were stained for parathyroid hormone (PTH) in an avidin-biotin complex (ABC) system, using a commercially available ABC kit (Vector Laboratories Inc.). The primary antibody is a polyclonal antiserum generated in rabbits against a synthetic human PTH. Negative controls were obtained from normal thyroid glands. In all three patients, the diseased gland was localized by ultrasound with cytologic and immunohistochemical confirmation, one on the right side and two on the left side. At surgical excision, the adenomas weighed 0.8 and 0.75 gram and the carcinoma, 0.75 gram. In two, intraoperative identification of the diseased gland was aided by ultrasound directed methylene blue injection into the adenoma. During a follow-up evaluation of eight to 24 months, serum calcium had remained normal in two patients, and one patient had become hypocalcemic and required calcium supplements. The preoperative localization allowed a direct surgical approach to the side in question in all patients. Ultrasonically guided FNA in an immunoperoxidase system can be a valuable preoperative localization technique for patients with recurrent hyperparathyroidism, thus avoiding extensive exploration of the neck with the subsequent complications.