Magnetic Resonance Imaging (MRI), is a medical diagnostic technique used in this study. The MRI creates images of the body using the principles of nuclear magnetic resonance, which is a spectroscopic technique used by scientists to obtain microscopic chemical and physical information about molecules, was performed in a 1.5T clinical magnet at UTMB.
MRI imaging was completed of the calves, thighs, and lumbar spine of each subject. For the calves after the positioning scans two sets of axial images are acquired, one a spin echo sequence with each slice 10mm thick and the other an inversion recovery sequence with a 12 mm thickness. The slice gaps were chosen to allow complete coverage of the calves. The field of view includes both legs; each sequence will take about 4 min. For the thighs, the imagings were the same as for the calves with appropriate changes in the field of view and slice gaps to allow complete coverage of the thighs. The lumbar spines were imaged using fast spin echo sequence. The images were sagittal images 3mm thick with gaps chosen to allow coverage of the spine, the acquisition time was about 3 min. Prior to the data acquisition, the subject was lying down for 15 minutes to allow the body fluids to equilibrate, during this time some of the required positioning scans were acquired. The legs were strapped together (with Velcro) and supported with foam at heels and knees.
Fast spin-echo T2-weighted scans had echo time (TE) = 11ms, effective TE = 66ms, and recovery time (TR) = 6000 – 9000ms (depending on the number of slices). The T2-weighted image set were collected in the thigh – between the iliac crest and the superior pole of the patella, and in the shank – from the tibial tubercle to the taro-crural joint.
The slice thickness was 10mm and 12mm (depending on the sequence), inter-slice gap 0.09mm (to minimize cross-talk between subsequent slices) (that is a Distal Factor of 30%), and field of view (FOV) was 270mm, and acquisition matrix 256 x 256 pixels. In order to improve visualization, the data sets were zero-filled to 512 x 512 pixels prior to Fourier transformation. The collection of each data set was required approximately 15 minutes.
This experiment has concluded in ground-based studies sponsored by the National Aeronautics and Space Administration's Human Adaptation and Countermeasures Division. This experiment was conducted during the Lunar Analog Feasibility Study. LSDA does not expect to receive results from this study.