Postflight changes in muscle volume, calf muscle transverse relaxation time, and total body composition were measured in 4 crewmembers after a 17-day mission and in 14-16 crewmembers in multiple shuttle/Mir missions of 16- to 28-wk duration. During the 17-day mission, all muscle regions except the hamstrings significantly decreased 3-10% compared with baseline. During the shuttle/Mir missions, there were significant decreases in muscle volume (5-17%) in all muscle groups except the neck. These changes, which reached a new steady state by 4 mo of flight or less, were reversed within 30-60 days after landing. Postflight swelling and elevation of calf muscle transverse relaxation time persisted for several weeks after flight, which suggests possible muscle damage. In contrast to the 17-day flight, in which loss in fat, but not lean body mass, was found (25), losses in bone mineral content and lean body mass, but not fat, were seen after the longer shuttle/Mir missions. The percent losses in total body lean body mass and bone mineral content were similar at approximately 3.4-3.5%, whereas the pelvis demonstrated the largest regional bone loss at 13%.

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Background. The state of the aorta is a key factor in the prognosis of the patient’s life, since the distension of the ascending aorta in systole determines the blood supply to the myocardium in diastole. Paramagnetic contrast-enhanced MRI provides a reliable assessment of pathological neoangiogenesis, however, in fact, studies of the aorta are performed descriptively, without calculating mechanical strength and extensibility. Objective. To develop and clinically test on the patients with atherosclerotic lesions and myocarditis a method for quantitative assessment of extensibility and mechanical elasticity of the aortic wall.Design and methods. Were examined 12 patients with acute myocardial infarction with ST segment elevation, as a control group 11 patients without clinical and instrumental signs of atherosclerosis of large arteries and aorta. All underwent MRI of the chest and heart with paramagnetic contrast enhancement (PMCE) and ECG synchronization. The indices of aortic distensibility, distensibility normalized to pulse BP, Young’s modulus of the aortic wall, systolic distension of the ascending aorta (mL), index of strengthening of the aortic wall in PMCE were calculated.Results. Ascending aortic distensibility decreased in patients with myocarditis and acute infarction. Young’s modulus and distensibility of the ascending aorta significantly correlated with the value of the aortic wall enhancement index in PMCE. Myocardial damage in acute infarction and myocarditis was noted with a decrease in systolic expansion of the ascending aorta below 10 ml due to its reduced elasticity.Conclusion. There is a relationship between pathological accumulation of a paramagnet in the wall of the ascending aorta, a decrease in its elasticity, a decrease in the volume of systolic aortic dilation, and the development of hypoperfusion myocardial damage. Magnetic resonance elastometry of the aortic wall makes it possible to assess violations of aortic distensibility and predict the development of ischemic damage in the myocardium of the left ventricle.

The term ~empty" sella turcica (EST) was first introduced by Bush in 1951, when in describing the data of 788 autopsies, the diaphragm of the sella was completely lacking in 5.5% of cases, and the hypophysis was spread out on the floor in the form of a thin lamina. This being the case, the sella appeared empty. As a disease, the EST was described in 1962 in patients subjected to surgical or radiation therapy because of endosellar adenoma of the hypophysis. It was later related to the syndrome of secondary EST. Primary EST is characterized by the presence of insufficiency of the diaphragm of the sella turcica with a decrease in the volume of the hypophysis and expansion of the intrasellar subarachnoid space. There are reports in the literature touching on the anatomical, roentgenological, and clinical manifestations of this pathological state [4,7,8]. However, the diagnosis of EST is complicated, since the clinical-roentgenological changes are insufficiently specific and may imitate an endosellar tumor of the hypophysis. The pneumocisternography and computerized tomography with preliminary contrasting that are used today [7,9] are invasive methods and are associated with a substantial radiation burden.One of the most promising methods in solving the problem of the recognition of EST is the new noninvasive method of endoscopic diagnosis, tomography based on the phenomenon of nuclear magnetic resonance, magnetic resonance tomography (MRT). The method makes it possible to carry out an investigation without the use of ionizing radiation or the introduction of iodide or any other contrast agents; the investigation can be carried out multiply, over the course of time, in the three mutually perpendicular planes; it has the Department of Endocrinology, I. M. Sechenov Moscow Medical Academy; Laboratory of Magnetic Resonance Tomography of the Cardiological Scientific Center, Russian Academy Medical Sciences, Moscow. capacity to differentiate soft tissue, and makes it possible to simultaneously obtain images of various organs and systems [1-3, 6, 11]. There are only individual reports relative to the use of MRT for the diagnosis of EST, which, in addition, are based on a small number of clinical observations, have highly contradictory data, relate mainly to secondary 9 EST following operative treatment of adenomas of the hypophysis, or include descriptions of patients with EST out of relationship with endocrinological symptomatology [5].The aim of this study was the determination of the capacities of MRT in the diagnosis of EST. 229 MATERIALS AND METHODSOne hundred and ten patients with the most prevalent diseases of the hypothalamohypophyseal system were examined. The distribution of the patients with the respect to nosologic forms is presented in Table 1.The diagnostic formulations were based on a comprehensive clinical-laboratory investigation, including x-ray craniography in two projections, investigation of the level of hormonal markers specific for the particular diseases (prolactin, TI'H, ACTH, STH, thyroid and adrena...

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The authors analyze the results of many-year application of magnetic imaging to the diagnosis of volume diseases of the adrenals. The method may be effectively used for topical diagnosis of such conditions. Due to some of its characteristics, such as clear differentiation of soft tissues, possibility of examination in 3 and more projections, safety, etc., magnetic imaging may be considered a method of choice in the diagnosis of adrenal tumors. It provides valuable information on the size, shape, localization, and dissemination of adrenal tumors and in some cases differentiates the variants of anatomical norm of the adjacent organs simulating adrenal tumors shown by other topographic methods. Features of magnetic image of tumors different by their hormonal activity: aldosteroma, pheochromocytoma, corticosteroma, "incidentaloma", and malignant tumors are described. Use of paramagnetic contrast agents appreciably improves the quality of magnetic resonance tomographic diagnosis of adrenal tumors, for it permits a more reliable conclusion on the tumor structure and its position amidst the adjacent vascular structures (abdominal aorta and inferior vena cava) and the parenchymatous organs (liver and kidneys), which is particularly valuable for planning surgery.

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