Synthesized images with intensified relaxation time effect

Saturation recovery sequence with the spin echo signals for imaging is the most basic method for MRI. Many investigations on the T1 and T2 values in lesions show that the strong correlations can be stated between T1 and T2 value prolongations. However, the prolongation in T1 and T2 give a reversed effect on the pixel intensity change in MRI. Therefore, in the conventional MRI, the pixel intensities show the inconveniently suppressed relaxation time prolongation effect. A new functional imaging method, which can show a monotonic image intensity change in accordance with the T1 and T2 prolongations in the brain tumors, is presented. This synthesized imaging is obtained by calculating images with pixel intensities in accordance with the following formula: I ∝ [1 - exp (-TR/T1)] exp (qTE/T2) where q is a constant with positive value. Our images are calculated without using such unstable calculations as exponentially decaying curve analysis. These images were useful to distinguish brain tumor from surrounding edema. This new imaging method will be applied routinely to clinical cases in future. (author)