Biomedical subjects
Publications and source records attributed to L M Vincent.
Extramedullary hematopoiesis occurring in the thorax is a well-known complication of a number of various blood dyscrasias, and its appearance with planar Tc-99m sulfur colloid marrow scintigraphy and transmission computed tomography (CT) has been described previously. The authors present a case of thoracic extramedullary hematopoiesis evaluated by CT and emission computed tomography (ECT).
Single and dual photon absorptiometry were performed at the mid-radius, distal radius and lumbar spine in 1105 non-athletic and 124 athletic Caucasian women aged 18-98 years. An age-related loss of bone mineral density in mg/cm2 (BMD) occurred at the three skeletal sites. It was first demonstrated that a single break in the regression line (BMD versus Age) best fit the data. The break represented the approximate age at which an increase in the rate of bone density loss occurred. This break is termed the 'cutpoint'. The approximate (average) age at which the cutpoint occurred was determined by segmented regression analysis with bone density as the dependent variable. The age range studied was between 45 and 55 years. At all three bone sites, the cutpoints in non-athletic women occurred between 47 and 52 years of age, corresponding roughly to the time of menopause. Following this cutpoint the rate of bone loss increased at all three locations in non-athletic women. In athletic women no cutpoint in BMD values could be demonstrated for this age range for the two radial sites. The number of lumbar spine measurements in this group was too small for analysis. The absence of a significant change in rate of bone loss in athletes could have been due to the relatively small number of subjects. It could also suggest that regular sustained exercise programs may delay or minimize the increased rate of loss of BMD which occurs in non-athletic women in the perimenopausal period.
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Blood pool activity in a medial splenic tubercle produced an apparent apical wall motion abnormality during radionuclide ventriculography.
We performed 32 overpressure radionuclide cisternography (ORNC) studies to examine 26 patients who were clinically suspected of having cerebrospinal fluid (CSF) fistula with rhinorrhea. Fifteen (47%) of these cisternography studies were positive, and the site of the leak was identified. No leak could be demonstrated in the other 17. Of 23 examinations performed in patients who had clinically documented CSF rhinorrhea, 15 (65%) were scintigraphically positive. The rapid cephalad transit of the radionuclide bolus allowed completion of the study within 30 to 45 minutes. Seven examinations were also performed with overpressure metrizamide CT cisternography (OMCTC), and five demonstrated concordant results with the radionuclide study. Patient discomfort and side effects were minimal. We conclude that radionuclide infusion cisternography is a safe, rapid, and accurate method of investigating a suspected or proven CSF rhinorrhea and that it is complementary to metrizamide cisternography.
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This is a cross-sectional study of bone densitometry in greater than 700 normal healthy white women ranging in age from 18 to 98 years. A modified procedure for single-photon bone density analysis of the distal radius is described and compared with dual-photon densitometric measurements of the second through fourth lumbar vertebrae. The distal radial site measured was separated from the ulna by 5 mm. This "5 mm" site was characterized according to trabecular and cortical bone content, measurement reproducibility, positioning precision, and the effects of wrist pronation or supination. The radial site demonstrated a bone density loss of less than 0.1%/year for normal women 25-50 years of age, increasing to 0.7%/year after 50 years of age. In contrast to the variability and inconsistency obtained by us and others utilizing the standard "9/10" site, bone loss with age at the new "5 mm" site correlated closely with generalized bone mineral loss of the axial skeleton. We suggest that there is a unique role for single-beam densitometric measurements of the radius, permitting the rapid and relatively inexpensive evaluation of large populations of women without requiring a visit to a medical center. Such a process can select those requiring further evaluation or medical attention.
This study measured radial and lumbar spine bone density in postmenopausal white female patients with nontraumatic fractures and their age-matched controls. Bone density measurements were made with a single-beam densitometer. Distal radial bone density measurements were made at the site at which the radius and ulna are separated by 5 mm, which is approximately 5 mm from the distal radioulnar joint. Lumbar spine density was obtained using a dual-beam densitometer. Density at the commonly used "2/3" site near the midradius was also measured. Forty-six crush fracture osteoporotic patients, 35 hip fracture patients, and 20 osteopenic patients referred to the clinic for back pain or excessive bone loss but with no history of nontraumatic fracture were studied. Bone density values at all sites in the patient populations were statistically reduced from control values (p less than 0.01). At a mean age of 62 years, density of the midradius was 12% below the control value. However, both vertebral and distal radial densities ("5 mm" site) were 25% below control values. The spine/distal radius ratio remained constant. It was demonstrated that bone density at the modified distal radial site could be used to predict vertebral density in osteopenic patients. An "at risk" value useful in screening procedures was determined as that distal radius density value greater than or equal to 95% of all values from fracture patients--325 mg/cm2. It is concluded that distal radial density at the new "5 mm" site can be used in conjunction with midradius density as a preliminary test for both generalized and trabecular bone mass loss in women.
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Three hemophiliac patients are presented who had gas within their pelvic pseudotumors demonstrated by computed tomography. Etiologies of the gas included iatrogenically introduced gas from infection, failed tube drainage of the pseudotumor, and a communication between the pseudotumor and the bladder containing a Foley catheter.
The sonographic appearance and differentiation of fluid collections within the gastrohepatic recess and lesser sac are described. The identification of the lesser omentum and stomach is fundamental to their separation. Accurate localization of upper abdominal fluid may be of aid in selecting an appropriate approach for paracentesis as well as directing the subsequent diagnostic work-up.
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Scintigraphic findings in a patient with biopsy-proven hypervitaminosis A included markedly impaired hepatic uptake of Tc-99m sulfur colloid but essentially normal uptake of Tc-99m DISIDA . This case presents a potential cause for image discordance with these two agents.
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The calcaneal varus angle is an important parameter used by orthopedic surgeons in their assessment of calcaneal fractures, and restoration of this angle is a major goal in the intraoperative reduction of such fractures. Plain radiographic techniques for the measurement of this angle may be difficult to apply. It is much simpler to measure this angle on CT, which is superior in demonstrating the complex anatomy of the calcaneus. However, a standardized method of measuring this angle by CT has not yet been developed. We measured the calcaneal varus angle in 48 subjects (31 normal feet and 62 feet with fractured calcanei) with three methods. The axial calcaneocuboid angle (the angle in the axial plane between the longitudinal axis of the calcaneus and a line drawn perpendicular to the calcaneocuboid joint) measured 25.3 +/- 7.3 degrees (mean +/- 1 SD) in normal feet and 28.9 +/- 8.5 degrees in fractured feet. The axial talocalcaneal angle (the angle between the longitudinal axes of the talus and the calcaneus in the axial plane) measured 20.9 +/- 9.2 degrees in normal feet and 29.2 +/- 11.3 degrees in fractured feet. The coronal talocalcaneal angle (the angle between the vertical axes of the talus and calcaneus in the coronal plane) measured 12.5 +/- 3.8 degrees in normal feet and 21.8 +/- 7.6 degrees in fractured feet. There was a statistically significant difference between the varus angle for normals and for fractured calcanei by all three methods of measurement (p less than or equal to 0.05). These measurements provide preliminary normative data for three methods of estimating the calcaneal varus angle in the normal and fractured hindfoot. These may be of value not only in the surgical restoration of the normal anatomic alignment of the fractured hindfoot but also in the preoperative assessment of congenital foot abnormalities. Although clinical validation is not yet available, our study suggests that the axial calcaneocuboid angle has several significant advantages over the other two methods.