To increase spatial resolution without affecting scan time, and all other parameters remaining the same, an MRI technologist can do which of the following?

• A. Increase frequency encoding steps
• B. Decrease receiver bandwidth
• C. Increase TR
• D. Decrease slice thickness

Answer: (A)

Increasing frequency encoding steps is a method to enhance spatial resolution in MRI imaging while maintaining the same scan time. By increasing the number of frequency encoding steps, the MRI system captures more data points across the frequency domain, which translates to finer spatial detail in the resulting images. This additional data aids in better distinguishing between closely spaced structures, thereby improving spatial resolution.

The other methods, while they have their own merits, would not achieve the same impact on spatial resolution without influencing the scan duration or other parameters. Decreasing receiver bandwidth, for example, can improve signal-to-noise ratio and enhance image quality, but it typically results in longer scan times as it requires more time to collect the same amount of data. Increasing the repetition time (TR) would also deteriorate scan efficiency by prolonging the overall scan time, while decreasing slice thickness can enhance spatial resolution but often necessitates longer scan times to collect sufficient data, especially if the overall imaging technique remains unchanged. These factors make increasing frequency encoding steps the most suitable option for maintaining scan time while improving spatial resolution.