Quantitative evaluation of k‐space reordering schemes for compatible dual‐echo arteriovenography (CODEA)

Abstract

Compatible dual-echo arteriovenography (CODEA) is a recently developed technique for simultaneous acquisition of time-of-flight MR angiogram (MRA) and blood oxygenation level-dependent MR venogram (MRV) using an echo-specific k-space reordering scheme. In this study, we evaluated and compared the image quality of CODEA MRA/MRV implemented with two different schemes of echo-specific k-space reordering: one along the 1st phase-encode direction (one-dimensional) only and the other along both phase-encode directions (two-dimensional). Our results showed that use of the two-dimensional reordering scheme improved contrast-to-noise ratio of small arteries by approximately 8%, although not statistically significant (P > 0.1). Contrast-to-noise ratio of the CODEA MRAs was better than that for the non-CODEA dual-echo MRA without k-space reordering (contrast-to-noise ratio increased in large arteries by approximately 10% and small arteries by approximately 45%; P < 0.1). Contrast-to-noise ratio of the CODEA MRAs was comparable with that of the conventional single-echo MRA for large arteries but reduced by approximately 20% for small arteries. Contrast-to-noise ratio of veins on the CODEA MRVs was equivalent to that of the conventional single-echo and the non-CODEA dual-echo MRVs. However, some veins in the CODEA MRVs showed stronger contrast than those in the single-echo MRV in relation to the contrast of neighboring arterial signals.