Fully-modelled blood-focused variable inversion times for 3D late gadolinium-enhanced imaging

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Medical Imaging Physics

Background:

• Variable heart rate during cardiac MRI, specifically Late Gadolinium-Enhanced (LGE) scans, can degrade image quality.
• Real-time adjustments using Variable Inversion Times (VTIs) in response to R-R interval changes can mitigate this issue.

Purpose of the Study:

• To investigate an extended single-cycle VTI method, termed fmVTI (fully modeling the longitudinal magnetization).
• To evaluate the in vivo and simulation performance of fmVTI for 3D LGE imaging.

Main Methods:

• Developed and applied VTI and fmVTI techniques for 3D LGE scans in 28 patients.
• Conducted numerical simulations using phantoms to assess ghosting in blood and myocardial scar.
• Assigned qualitative image quality scores for left atrial wall clarity and ghosting in patient scans.

Main Results:

• Numerical simulations showed significant reductions in blood ghosting (VTI: 410 ± 710 vs. fmVTI: 68 ± 40) and scar ghosting (VTI: 830 ± 1300 vs. fmVTI: 510 ± 730) with fmVTI.
• No significant differences were observed in qualitative image quality scores for left atrial wall clarity or total ghosting in patient studies.
• Simulations indicated fmVTI reduced Mz variability in blood signal, leading to less ghosting.

Conclusions:

• The fmVTI method demonstrated potential for reducing ghosting in cardiac MRI simulations.
• Observed ghosting reductions in simulations were not translated to improved patient scan quality.
• Other sources of image artifact, such as phase-encode ghosting and blurring, likely obscured the benefits of fmVTI in clinical studies.