Towards elimination of the dark-rim artifact in first-pass myocardial perfusion MRI: Removing Gibbs ringing effects using optimized radial imaging

Abstract

Purpose Subendocardial dark-rim artifacts (DRAs) remain a major concern in first-pass perfusion (FPP) myocardial MRI and may lower the diagnostic accuracy for detection of ischemia. A major source of the DRA is known to be the “Gibbs ringing” effect. We propose an optimized radial acquisition strategy aimed at eliminating ringing-induced DRAs in FPP. Theory and Methods By studying the underlying point spread function (PSF), we show that optimized radial sampling with a simple reconstruction method can eliminate the oscillations in the PSF that cause ringing artifacts. We conduct realistic MRI phantom experiments and in-vivo studies (n=12 healthy humans) to study the artifact behavior of the proposed acquisition scheme in comparison to a conventional Cartesian protocol. Results Simulations and phantom experiments verify the theoretical expectations. Our in-vivo studies show that optimized radial imaging is capable of significantly reducing DRAs in the early myocardial enhancement phase (during which the ringing effect is most prominent and may obscure perfusion defects) while providing equivalent resolution and similar image quality as conventional Cartesian imaging. Conclusion The developed technical framework and results demonstrate that, compared to conventional Cartesian techniques, optimized radial imaging with the proposed optimizations significantly reduces the prevalence and spatial extent of DRAs in FPP imaging.

Adenosine Stress Cardiovascular Magnetic Resonance With Variable-Density Spiral Pulse Sequences Accurately Detects Coronary Artery Disease

“…utilizes a similar approach. 29 A higher readout bandwidth is used to achieve a higher spatial resolution with the same readout duration at the cost of a reduction in SNR. The data is apodized (in their case by a Gaussian filter) to remove residual ringing artifacts, effectively under-weighting the high spatial frequencies and recovering SNR.…”

Recent Advances in Cardiovascular Magnetic Resonance

“…20 Radial perfusion CMR is well suited for continuous acquisition and self-gating, effectively eliminating the need for ECG gating, and has the potential to achieve high diagnostic accuracy in arrhythmic patients. 21 Radial perfusion imaging, using a slice-interleaved continuous approach (Figure 3C), has demonstrated potential for acquiring high-resolution perfusion images (1.4 mm in-plane) at the end-systolic phase without the need for ECG gating.…”

Coronary Microvascular Dysfunction ― Epidemiology, Pathogenesis, Prognosis, Diagnosis, Risk Factors and Therapy ―

“…42 Results of CMR have correlated well with results from invasive measurement. 43 A drawback of CMR is the subendocardial dark-rim artifact, which lowers the diagnostic accuracy of ischemia, but optimized radial imaging has significantly reduced such artifact 44 (Figure 3). CMR is useful for assessing the prognosis of patients with ischemic heart disease.…”