CINE turbo spin echo imaging

Abstract

High-resolution turbo spin echo (TSE) images have demonstrated important details of carotid artery morphology; however, it is evident that pulsatile blood and wall motion related to the cardiac cycle are still significant sources of image degradation. Although ECG gating can reduce artifacts due to cardiac-induced pulsations, gating is rarely used because it lengthens the acquisition time and can cause image degradation due to nonconstant repetition time. This work introduces a relatively simple method of converting a conventional TSE acquisition into a retrospectively ECG-correlated cineTSE sequence. The cineTSE sequence generates a full sequence of ECG-correlated images at each slice location throughout the cardiac cycle in the same scan time that is conventionally used by standard TSE sequences to produce a single image at each slice location. The cineTSE images exhibit reduced pulsatile artifacts associated with a gated sequence but without the increased scan time or associated nonconstant repetition time effects. Magn Reson Med 66:1286-1292,

Free-breathing black-blood CINE fast-spin echo imaging for measuring abdominal aortic wall distensibility: a feasibility study

“…The currently available technique of ECG-gated, fully sampled CINE FSE would take a scanning time approximately 16 times longer than static FSE. Unlike fully sampled CINE FSE, variable-density sampling can be performed within a scanning time only 2 -4 times longer than static FSE imaging (Mendes et al , 2011). This scanning time was tolerable for all the healthy subjects in this study.…”

“…Figure 4 illustrates the concept of variable-density sampling, which retrospectively constructs the sparse k-space domain and time domain (k y − t) for the subsequent image reconstruction. The variable-density sampling method based on Mendes et al (Mendes et al , 2011) was already established, and we doubled the number of excitations to 88 to increase the signal-to-noise ratio (SNR) around the abdominal aorta. The sampling density is higher at the center of the k-space than the peripheral k-space: the center of the k-space has 24 temporal samples, and there are 96 samples distributed across the -2 and +2 lines.…”

“…However, a routine FFT does not allow for spatial and temporal regularizations, and an iterative algorithm is needed for regularization purposes. The implemented reconstruction was based on the method proposed by Mendes et al (Mendes et al , 2011) and the temporally constrained reconstruction (Adluru et al , 2007). A slight difference between previous work and this study is that we added the spatial regularization terms.…”

“…This paper describes the development of a free-breathing black-blood CINE FSE method for measuring abdominal aortic wall motion. Recently, CINE FSE sequences have combined variabledensity sampling with advanced reconstruction methods (Boesen et al , 2015;Mendes et al , 2011) to perform black blood CINE imaging of the carotid artery. This study implemented a similar variabledensity sampling strategy (Boesen et al , 2015;Mendes et al , 2011) to allow efficient acquisitions, together with inner volume excitation (Feinberg et al , 1985) and improved blood suppression to allow free-breathing black-blood CINE FSE of the abdominal aorta.…”

Fast spin echo imaging of carotid artery dynamics

“…There has been recent interest in cardiac phase resolved black‐blood imaging of the carotid arteries . We further developed a cine FSE imaging approach that was first implemented by Mendes et al and assessed its suitability for characterizing the common carotid artery over the cardiac cycle by comparing it to a prospectively gated FSE method. Cine FSE images acquire multiple cardiac phase images in roughly the same scan time required for a multiple signal average black‐blood FSE technique that is currently used for wall composition assessment .…”