CArtesian sampling with Variable density and Adjustable temporal resolution (CAVA)

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging Physics

Background:

• Dynamic MRI applications require precise temporal resolution for accurate physiological measurements.
• Current methods for adjusting temporal resolution in phase contrast MRI (PC-MRI) are often limited or require pre-acquisition planning.

Purpose of the Study:

• To develop and validate a novel variable density Cartesian sampling method for dynamic MRI.
• To enable retrospective adjustment of temporal resolution in real-time PC-MRI.

Main Methods:

• The CArtesian sampling with Variable density and Adjustable temporal resolution (CAVA) method generates phase encoding indices using a golden ratio increment.
• Variable density is achieved through nonlinear stretching of these indices, followed by rounding to the nearest integer.
• CAVA's performance was assessed using a pulsatile flow phantom and real-time, free-breathing PC-MRI data from healthy volunteers.

Main Results:

• CAVA successfully enabled image recovery with retrospectively selected temporal resolutions.
• Image quality and flow quantification accuracy using CAVA were comparable to existing pseudo-random sampling techniques.
• Flow quantification results obtained with CAVA showed good agreement with breath-held segmented acquisitions.

Conclusions:

• The CAVA method offers a flexible approach for dynamic MRI by allowing retrospective adjustment of temporal resolution.
• This technique enhances the utility of PC-MRI for real-time, free-breathing applications.