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Biomedical subjects

C A Wesolowski

Publications and source records attributed to C A Wesolowski.

8 recordsLinked to original sources
PubMed1995

Effect of carbamazepine and valproate on bone mineral density.

OBJECTIVE: To examine the effect of carbamazepine and valproate monotherapy on bone mineral density in children. METHODS: Axial (second, third, and fourth lumbar vertebrae) and appendicular (distal third of radius) bone mineral density was measured by dual-energy x-ray absorptiometry in 27 healthy children and 26 children with uncomplicated idiopathic epilepsy treated with either carbamazepine (n = 13) or valproate (n = 13) for more than 18 months. Control subjects and patients were similar with respect to age, race (all white), and geographic area, and had no dietary restrictions, neurologic impairment, or physical handicaps. RESULTS: Subjects were seizure-free for more than 6 months on a regimen of carbamazepine or valproate therapy, and had mean serum trough levels of 6.88 +/- 2 micrograms/ml and 72.04 +/- 45.6 micrograms/ml, respectively. Dietary calcium intake was similar in control and treated groups. After correction for gender and age, children treated with valproate had a 14% (p = 0.003) and 10% (p = 0.005) reduction in bone mineral density at the axial and appendicular sites, respectively. The reduction in bone mineral density increased with the duration of valproate therapy. Carbamazepine did not significantly reduce bone mineral density. CONCLUSION: Valproate montherapy, but not carbamazepine therapy, significantly reduces axial and appendicular bone mineral density in children with idiopathic epilepsy and may increase their risk of osteoporotic fractures.

Absorptiometry, Photon↗
PubMed1992

Comparison of Tl-201 renal uptake with Tc-99m DTPA angiorenography in patients with hypertension. Measures of renal asymmetry.

Renal uptake of Tl-201 reflects renal perfusion and may have a role in defining renal asymmetry in patients with hypertension who are referred for myocardial scintigraphy. The authors compared two methods of quantitating differential renal uptake of Tl-201, with similar data obtained from the angiographic and renal uptake (RU) phases of Tc-99m DTPA scintigraphy in 35 patients with hypertension. For Tl-201, asymmetry in renal counts was quantitated based on a simple outline technique or on interpolative background subtraction of 5-minute posterior images. Inter-observer and intra-observer variability among duplicate measurements were lower for Tl-201, particularly with interpolative background subtraction, than for Tc-99m DTPA. Renal/background ratios were similar for Tl-201 and RU-phase Tc-99m DTPA images when considering liver, spleen, or inter-renal regions as background; however, paraspinal uptake was relatively higher with Tl-201 (P less than 0.01). Qualitatively, renal asymmetry scores with the two radiotracers agreed (r = 0.89, blinded readings by four observers), although asymmetry was more marked with Tl-201 (P = 0.06). Measurements with Tl-201 agreed with both phases of Tc-99m DTPA (r = 0.96 to 0.98), but interpolative background subtraction systematically yielded greater inter-renal asymmetry than RU (P less than 0.01), reflecting the qualitative impression. Thus, ancillary Tl-201 imaging reflects differences between the kidneys in a fashion similar but not identical to Tc-99m DTPA scintigraphy.

Angiography, Digital Subtraction↗
PubMed1990

Renal uptake of Tl-201 in hypertensive patients undergoing myocardial perfusion imaging.

The detection of renovascular disease (RVD) has particular relevance in hypertensive patients (HP) who have symptoms of target organ damage. To evaluate the possibility of RVD in HP undergoing myocardial perfusion scintigraphy for chest pain symptoms, posterior renal images were obtained at 1-3 hours after Tl-201 injection. Analog and computer images were obtained for 5 minutes in 45 HP; 12 patients with no history of hypertension or renal disease served as normal controls. For qualitative analysis, images were coded and read by three observers as to symmetry of renal uptake. Differential renal uptake of Tl-201 (DRU) was quantitated on computer images. In normal controls, uptake was agreed on as symmetric. In HP, 6 patients had marked asymmetry of DRU and 4 had possibly significant asymmetry; 2 had decreased uptake in both kidneys suggesting bilateral RVD or nephrosclerosis. Objective correlation with DRU was obtained in 10 HP who had contrast angiography, confirming 4 cases of unilateral RVD and 2 of bilateral RVD. Thirteen patients also had renography with Tc-99m DTPA; differential renal function by this modality correlated well with DRU of Tl-201 (r = 0.98). Thus, DRU of Tl-201 can be used as a supplement to myocardial scintigraphy to identify HP who require further evaluation and treatment of RVD.

Adult↗
PubMed1988

Avoidance of errors related to renal depth during radionuclide evaluation of renal perfusion.

Quantitative renal imaging is subject to errors related to varying renal depth. Lateral projection images, ultrasound, and geometric mean calculations can be utilized to measure renal depth or to correct for variations in the attenuation of renal activity. However, each of these methods is time consuming and each has the potential for introducing additional errors. As an alternative, the authors propose the use of quantitative indices that are insensitive to the effects of attenuation. This report illustrates how transit-time-distribution (TTD) parameters can be used to assess renal perfusion independent of varying renal depth.

Humans↗
PubMed1988

New methods of examining gamma camera collimators.

New methods are proposed and described to examine the quality of gamma camera collimators in two special performance categories, namely, uniformity in regional efficiency and regional variations in channel tilt. These two performances are critical areas for SPECT imaging. Results obtained from experimental and commercial collimators illustrate the variability seen for these performance characteristics in currently available collimators.

Quality Control↗
PubMed1987

Renal arteriovenous transit times of technetium-radiolabeled chelates.

A noninvasive method was developed for quantitating the distribution of renal arteriovenous transit times of technetium-99m (99mTc) radiopharmaceuticals. Using this method, the characteristic transit times and amplitudes of the first two components of [99mTC] DTPA or MDP transit through the renal vasculature were calculated. The first component amplitude (A1) was evaluated for its ability to discriminate between 20 hypertensive patients with renovascular disease and 21 normotensive subjects. A1 was compared with three other quantitative indices: the ascending slope of the initial renal time-activity curve, the kidney-to-aorta slope ratio (K/A), and renal size. A1 nearly perfectly separated the hypertensive patients from the normotensive subjects; the ability of A1 to discriminate between these two groups is clearly superior to renal size, the initial renal slope, and K/A. We conclude that measurements of the intrarenal distribution of blood flow have distinct advantages over indices of renal blood flow that have been derived from scintillation camera measurements of 99mTc radiopharmaceuticals.

Humans↗
PubMedDate not supplied

A direct modeling approach to the early renal vascular transit of 99mTc chelates.

Delay channel integral methods are developed and applied for analyzing human renal scintiangiographic data produced after peripheral venous injection of a 99mTc chelete. The results include information for two renal vascular compartments (C1, C2) and a residual compartment (Cr). Each vascular compartment is associated with a fraction of the total renal plasma flow (A1, A2) and a mean transit time (T1, T2). The residual compartment has the residual plasma flow fraction Ar. The results obtained in 40 normal kidneys are presented and compared theoretically to the results from other methods.

Algorithms↗