Errors in the assessment of the efficacy of MRI pulse sequences

The effects of the echo delay TE on contrast in saturation recovery MRI have been analyzed both theoretically and with experimental brain scans. It is demonstrated that the influence of the TE values offered as minimal values by all major current equipment manufacturers is not insignificant, but produces a degree of T 2 weighting that considerably degrades the useful contrast that could be obtained from T 1 weighted studies. Consequently, conclusions drawn about the relative performances of T 1 and T 2 weighted sequences may be incorrect if based on saturation recovery images obtained with inappropriate echo times.