What is the main function of TE in MRI?

The main function of TE, or echo time, in MRI is to determine the extent of T2 decay before signal acquisition. TE is the time interval between the application of the radiofrequency (RF) pulse and the peak of the echo signal that is received. During this period, the transverse magnetization of the tissue decreases due to T2 relaxation processes.

As tissues have different T2 relaxation times, setting various TE values allows for differentiation of tissues based on their T2 properties. Shorter TE values capture signals before significant T2 decay occurs, which can enhance the visibility of structures with longer T2 times. Conversely, longer TE values can highlight differences in tissues with shorter T2 times, making it key to image contrast and overall image quality.

Understanding the role of TE is critical for optimizing MRI scans and achieving desired image characteristics. This fundamental concept is essential for radiologists and technicians to accurately interpret images and diagnose conditions effectively.