Measurement of trabecular bone mineral density in the femur in vitro by using the coherent to Compton scatter ratio.
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Biomedical subjects
Publications and source records attributed to J D Craven.
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Trabecular bone mineral density (TBMD) was measured in vivo in the calcaneus by a new method that uses the ratio of coherent to Compton-scattered photons arising from irradiation of a small volume of trabecular bone by a gamma ray source with highly collimated geometry. TBMD values for healthy men (22-77 years) were in the range of 180-357 mg/ml, and values for healthy women (18-73 years) were in the range of 160-321 mg/ml. In contrast, values in a small group of paraplegics were in the range of 90-199 mg/ml.
Using a method combining the velocity of ultrasound and photon absorptiometry in the human radius in vivo, the authors measured the speed of sound in bone (U) and bone mineral content (BMC). From these measurements and a "simple" bone model, they then computed the bone mineral density, compact bone density, and modulus of elasticity. The accuracy of these parameters and of the bone model is assessed, and normal values for each parameter are given and compared with published values. The authors feel that a combination of U and BMC permits better discrimination between normal and abnormal in patients with osteoporosis or metabolic bone disease than either parameter alone.
The reliability of data obtained from the Norland-Cameron Bone Mineral Analyzer has been questioned and the possibility of an inherent calibration error in the machine has been raised. To make an absolute measurement of the instrumental accuracy, bone mineral content measured by the bone mineral analyzer was compared with an absolute value obtained by the ashing method. The instrument bone mineral content values were found to be higher by about 6.5%. The ash content (%), bone mineral density, and compact bone density in these same bone samples were 62.9%, 1.346 g/cm3, and 2.140 g/cm3, respectively, as determined by direct measurement.
Fibromuscular dysplasia (medial type) of the radial and ulna arteries, hitherto unreported, has been demonstrated angiographically following the malfunction of an arteriovenous shunt created for dialysis. Retrograde dilatation of the segmental stenoses caused some improvement in flow. No causal relationship is claimed between fibromuscular dysplasia and the arteriovenous shunt.
A long-term retrospective evaluation was done on the preoperative and postoperative radiographic studies from patients who had undergone the ileal ureter operation. The comparative studies demonstrated decreased or stable pelviocaliceal dilatation, no measurable parenchymal loss, frequent high pressure vesico-ileac reflux and decreased number of renal calculi. Radiographically there was no evidence of renal morphological deterioration.
The modulus of elasticity was derived by combining the velocity of ultrasound measurements and photon absorption (Norland-Cameron method) in human cortical bone (proximal radius) in vivo. The results compare favorably with published values of the elasticity modulus obtained in vitro. Values obtained for a heterogeneous group of patients with bone and joint complaints differed from those of normal volunteers.
The natural history of the upper tracts (170 renal units) of 87 patients undergoing total cystectomy and ileal loop diversion has been followed roentgenologically for up to seven years. The complications inherent in the procedure are illustrated and the appearances of new upper tract tumors demonstrated. Of 126 renal units which was obstruction of the anastomosis, seen in 29 units. The need for regular contrast material examination of the surgically modified upper tracts is emphasized.
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