title: Changes in nuclear magnetic resonance (T2) relaxation of limb tissue with bed rest.
abstract: Bed rest is used to simulate the effects of weightlessness on human physiology. A spin-echo procedure was used to image the lower leg of 15 normal male volunteers before and after 5 weeks of horizontal bedrest. In addition to noninvasively measuring muscle size changes, accurate T2 images were produced to investigate possible relaxation time changes immediately (2-4 h) and 1-2 days after bed rest. Subcutaneous fat showed no change in T2, bone marrow showed a decrease, and muscle showed no change immediately after bed rest but increased 1-2 days following reambulation.
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D001510:Bed Rest; D001853:Bone Marrow / Q000033:anatomy & histology; D006801:Humans; D007866:Leg / Q000033:anatomy & histology*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009132:Muscles / Q000033:anatomy & histology; D013997:Time Factors; D014893:Weightlessness