PURPOSE: To determine the test-retest precision of functional MR maps of regions in the brain "activated" by sensory, motor, and cognitive tasks. METHODS: Echo-planar images were acquired at 1.5 T in four subjects during voluntary motor activity involving the thumb and fingers and during tactile stimulation of the palm. Each subject performed the two tasks twice. Functional images of each task were generated at three thresholds. Test-retest precision was calculated in terms of two ratios: 1) the pixels activated in both iterations of the tasks in proportion to the pixels activated by either iteration of the task, and 2) the ratio modified to include first-order neighboring pixels. The first is referred to as pixel precision, and the latter as first-order-neighbor pixel precision. RESULTS: In each subject, activation from the first and second iteration of each task was located in the same region of the same gyrus. Pixel precision was .57 for the two tasks (at a threshold of 0.50). First-order-neighbor precision was greater than .80 for the two tasks at the same threshold. CONCLUSION: High test-retest precision can be obtained in functional MR.
PURPOSE: To determine the test-retest precision of functional MR maps of regions in the brain "activated" by sensory, motor, and cognitive tasks. METHODS: Echo-planar images were acquired at 1.5 T in four subjects during voluntary motor activity involving the thumb and fingers and during tactile stimulation of the palm. Each subject performed the two tasks twice. Functional images of each task were generated at three thresholds. Test-retest precision was calculated in terms of two ratios: 1) the pixels activated in both iterations of the tasks in proportion to the pixels activated by either iteration of the task, and 2) the ratio modified to include first-order neighboring pixels. The first is referred to as pixel precision, and the latter as first-order-neighbor pixel precision. RESULTS: In each subject, activation from the first and second iteration of each task was located in the same region of the same gyrus. Pixel precision was .57 for the two tasks (at a threshold of 0.50). First-order-neighbor precision was greater than .80 for the two tasks at the same threshold. CONCLUSION: High test-retest precision can be obtained in functional MR.
Authors: Joseph A Maldjian; Paul J Laurienti; Lance Driskill; Jonathan H Burdette Journal: AJNR Am J Neuroradiol Date: 2002 Jun-Jul Impact factor: 3.825
Authors: Arash Babaei; B Douglas Ward; Shahryar Ahmad; Anna Patel; Andrew Nencka; Shi-Jiang Li; James Hyde; Reza Shaker Journal: Am J Physiol Gastrointest Liver Physiol Date: 2012-07-05 Impact factor: 4.052