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First‐pass myocardial perfusion MRI with reduced subendocardial dark‐rim artifact using optimized Cartesian sampling
Author(s) -
Zhou Zhengwei,
Bi Xiaoming,
Wei Janet,
Yang HsinJung,
Dharmakumar Rohan,
Arsanjani Reza,
Bairey Merz C. Noel,
Li Debiao,
Sharif Behzad
Publication year - 2017
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25400
Subject(s) - ringing artifacts , magnetic resonance imaging , image quality , artifact (error) , ringing , perfusion , sampling (signal processing) , algorithm , myocardial perfusion imaging , apodization , nuclear medicine , medicine , computer science , artificial intelligence , physics , radiology , computer vision , image (mathematics) , optics , enhanced data rates for gsm evolution , filter (signal processing)
Purpose The presence of subendocardial dark‐rim artifact (DRA) remains an ongoing challenge in first‐pass perfusion (FPP) cardiac magnetic resonance imaging (MRI). We propose a free‐breathing FPP imaging scheme with Cartesian sampling that is optimized to minimize the DRA and readily enables near‐instantaneous image reconstruction. Materials and Methods The proposed FPP method suppresses Gibbs ringing effects—a major underlying factor for the DRA—by “shaping” the underlying point spread function through a two‐step process: 1) an undersampled Cartesian sampling scheme that widens the k ‐space coverage compared to the conventional scheme; and 2) a modified parallel‐imaging scheme that incorporates optimized apodization ( k ‐space data filtering) to suppress Gibbs‐ringing effects. Healthy volunteer studies ( n = 10) were performed to compare the proposed method against the conventional Cartesian technique—both using a saturation‐recovery gradient‐echo sequence at 3T. Furthermore, FPP imaging studies using the proposed method were performed in infarcted canines ( n = 3), and in two symptomatic patients with suspected coronary microvascular dysfunction for assessment of myocardial hypoperfusion. Results Width of the DRA and the number of DRA‐affected myocardial segments were significantly reduced in the proposed method compared to the conventional approach (width: 1.3 vs. 2.9 mm, P < 0.001; number of segments: 2.6 vs. 8.7; P < 0.0001). The number of slices with severe DRA was markedly lower for the proposed method (by 10‐fold). The reader‐assigned image quality scores were similar ( P = 0.2), although the quantified myocardial signal‐to‐noise ratio was lower for the proposed method ( P < 0.05). Animal studies showed that the proposed method can detect subendocardial perfusion defects and patient results were consistent with the gold‐standard invasive test. Conclusion The proposed free‐breathing Cartesian FPP imaging method significantly reduces the prevalence of severe DRAs compared to the conventional approach while maintaining similar resolution and image quality. Level of Evidence: 2 J. Magn. Reson. Imaging 2017;45:542–555.