Robert W . Parkey

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Exercise is known to produce changes in the amount and distribution of water in skeletal muscle. Because MR imaging is highly sensitive to changes in water distribution, these changes should be detectable under appropriate imaging conditions. Imaging of the forearms and/or legs was performed in 16 volunteers at 0.35 T, before and after exercise. Exercises(More)
PURPOSE To assess correlations between muscle edema on magnetic resonance (MR) images and clinical indexes of muscle injury in delayed-onset muscle soreness (DOMS) produced by submaximal exercise protocols. MATERIALS AND METHODS Sixteen subjects performed 36 elbow flexions ("biceps curls") at one of two submaximal workloads that emphasized eccentric(More)
Sports-related muscle pain is frequent in both trained and untrained persons; however, its severity and significance may be difficult to assess clinically. The authors used magnetic resonance (MR) imaging to evaluate acute strains and delayed-onset muscle soreness in sedentary subjects and postmarathon myalgia in trained runners. MR imaging documented the(More)
To assess the role of glycogenolysis in mediating exercise-induced increases in muscle water as monitored by changes in muscle proton relaxation times on magnetic resonance imaging (MRI) and cross-sectional area (CSA), five patients with myophosphorylase deficiency (MPD) were compared with seven controls. Absolute and relative work loads were matched during(More)
Because determination of neurologic integrity after severe limb trauma is crucial in patient care, the authors assessed magnetic resonance (MR) imaging as a tool to map denervated motor units of skeletal muscle in patients with traumatic peripheral neuropathy. Denervation was confirmed in 22 patients with use of electromyography, surgery, or both. MR(More)
Computed tomography (CT) has been used to quantitate acute myocardial infarct size in isolated, arrested canine hearts. Acute myocardial infarcts were produced in 20 hearts by either left anterior descending (13 dogs) or circumflex coronary artery ligation (seven dogs). Each animal was given iodinated contrast media intravenously immediately before(More)
To enhance the versatility of the short-tau inversion-recovery (STIR) sequences, the authors determined a range of repetition time (TR) and inversion time (TI) combinations that suppress signal intensity from fat by study of both patient and phantom images. To make fast STIR images, variations in the following pulsing conditions were studied with use of an(More)
Left ventricular (LV) performance at rest and during multilevel exercise in the supine and upright positions was studied in seven normal subjects with equilibrium radionuclide ventriculography. The mean left ventricular end-diastolic volume (LVEDV) during supine rest was 107 4 10 ml (± SEM) and 85 ± 6 ml (p < 0.02) in the upright position; the mean resting(More)
The accuracy and reproducibility of magnetic resonance (MR) imaging in the determination of left ventricular mass in humans was investigated. Left ventricular wall volume was measured from ten short-axis, end-diastolic MR images that spanned the left ventricle. Mass was estimated on the basis of average left ventricular wall volume and an assumed myocardial(More)