Which statement best represents the requirements for T2 weighted images?

For T2 weighted images, it is crucial to understand the relationship between the time to echo (TE) and the time to repetition (TR) settings in MRI. T2 weighting is achieved when we allow the spins of the hydrogen nuclei in the tissues to interact with one another over a longer time period, which is primarily influenced by a long TE. A longer TE gives the tissue enough time to experience T2 relaxation, highlighting differences between tissue types based on their water content and the T2 decay characteristics.

In addition, having a long TR contributes to T2 weighting by ensuring that the longitudinal magnetization of the tissues is given ample time to recover before the next excitation pulse. This further enhances the sensitivity of the imaging to T2 differences within the tissues, producing clearer contrast that allows for better differentiation between structures.

Thus, both a long TE and a long TR are necessary to optimally emphasize the T2 relaxation properties of the tissues, leading to the best representation of T2 weighted images. This understanding is fundamental for anyone working with MRI technology, as it impacts the quality and interpretability of scans in clinical practice.