Magnetic Resonance Imaging (MRI) Practice Test

What parameter can affect the contrast resolution of T2 weighted images?

1. Bandwith

2. Echo Time (TE)

3. Repetition Time (TR)

4. Field Strength

The correct answer is: Echo Time (TE)

The parameter that significantly affects the contrast resolution of T2 weighted images is Echo Time (TE). In MRI, T2 weighted images are designed to highlight differences in the T2 relaxation times of tissues, which reflect how quickly protons in the tissue lose their coherence after the application of a radiofrequency pulse. By adjusting the Echo Time, the timing of when the signal is collected after the radiofrequency pulse, one can maximize the differences in signal intensity between tissues with differing T2 values. Longer Echo Times can enhance contrast in T2 weighted images because they allow for greater relaxation of tissue signals, allowing T2-rich tissues, such as fluid, to appear brighter compared to T2-poor tissues, like fatty or fibrous tissues. As a result, optimizing TE is crucial for achieving the best contrast resolution in T2 images, facilitating clearer visualization of pathology. Other parameters like Bandwidth, Repetition Time (TR), and Field Strength influence image quality but do not have the same direct relationship with contrast resolution on T2 weighting as Echo Time does. Bandwidth affects the signal-to-noise ratio and the spatial resolution, while TR mainly affects T1 weighting and overall image contrast rather than specifically enhancing T2 contrast. Field strength can improve signal intensity and