Application of the chirp z-transform to MRI data

Area of Science:

• Magnetic Resonance Imaging
• Signal Processing
• Spectroscopy

Background:

• Single-point imaging sequences like SPRITE are crucial for applications such as T2* mapping and signal averaging.
• Accurate field-of-view scaling is essential for quantitative analysis in these sequences.
• Existing methods may introduce artifacts or lose critical signal and phase information during scaling.

Purpose of the Study:

• To introduce and theoretically describe a novel chirp z-transform (CZT) algorithm for field-of-view scaling.
• To demonstrate the algorithm's ability to preserve signal intensity and phase during scaling.
• To compare the performance of the CZT method with conventional image-space interpolation techniques.

Main Methods:

• Implementation of a chirp z-transform (CZT) algorithm operating entirely in k-space.
• Application of the CZT algorithm for field-of-view scaling in single-point imaging sequences.
• Comparative analysis against traditional fast Fourier transformation followed by image-space interpolation.

Main Results:

• The developed CZT algorithm successfully scales the field-of-view while preserving signal intensity and phase.
• The CZT method demonstrates particular utility for SPRITE imaging of nuclei with short relaxation times (e.g., sodium at high field).
• The k-space CZT approach shows advantages over conventional image-space interpolation methods.

Conclusions:

• The chirp z-transform offers a robust and accurate method for field-of-view scaling in SPRITE imaging.
• This technique enhances the quality and reliability of quantitative magnetic resonance imaging, especially for challenging nuclei.
• The CZT algorithm provides a valuable advancement for advanced MRI applications requiring precise data manipulation.