Usefulness of Controlled Aliasing in Parallel Imaging Results in Higher Acceleration in Gadoxetic Acid–Enhanced Liver Magnetic Resonance Imaging to Clarify the Hepatic Arterial Phase

Abstract

The CAIPIRINHA technique improved the image quality of hepatic arterial phase imaging with gadoxetic acid, reducing the number of non-diagnostic arterial phase studies.

Comparison of Three, Motion-Resistant MR Sequences on Hepatobiliary Phase for Gadoxetic Acid (Gd-EOB-DTPA)-Enhanced MR Imaging of the Liver

“…The acquired k-space samplings are offset from the normal grid-like sampling by shifting the sampling positions of alternate rows with respect to the partition-encoding direction (7,9,10). This technique can save the acquisition time and the breathholding time more effectively than the generalized auto calibrating partially parallel acquisition (GRAPPA) technique (8)(9)(10)13). In cooperative patients, our study showed that the 3D GRE with CAIPIRINHA was superior to 3D radial GRE with GA and ILAB for all qualitative analyses.…”

“…The newly developed, parallel acceleration technique (3D gradient recalled echo [GRE], with controlled aliasing in parallel imaging, resulting in higher acceleration [CAIPIRINHA]), can save image acquisition time, by modifying the phase encoding sampling manner, which leads to reduced aliasing artifacts and provides better image quality, although patients cannot hold their breath long enough (7)(8)(9)(10). Therefore, this rapid imaging technique that reduces respiration artifacts, may propel patients with short breathing capacity, into routine clinical MR practice.…”

Shortened breath-hold contrast-enhanced MRI of the liver using a new parallel imaging technique, CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration): a comparison with conventional GRAPPA technique

“…Third, we could not compare the 3 datasets during arterial or portal phase in the same patients because the images dramatically change every second from arterial to venous phase in dynamic contrast-enhanced imaging. However, Tanimoto et al [19] reported that ringing artifacts could be reduced by a shorter scan time, and Park et al [13] reported that the CAIPIRINHA-VIBE with AF = 4 reduced the number of non-diagnostic arterial-phase images compared with the conventional protocols in different patients, with its already proven utility in dynamic contrast-enhanced imaging.…”

“…First, the 2-s difference in breath holding was not negligible for elderly patients. Second, parallel imaging artifacts and motion artifacts were difficult to exactly distinguish in some cases as discussed previously [13], and the score of motion artifacts might be slightly overestimated by parallel imaging artifacts. An acquisition time of approximately 10 s was thought to be suitable for the breath-hold examination especially for elderly patients, and further research on the most appropriate scan time is necessary.…”

“…Controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) is a new parallel imaging technique that modifies aliasing artifacts and SNR loss based on parallel imaging reconstruction algorithms during acquisition of multi-slice or 3D data [2,4,8,[12][13][14]. In this technique, the sampling pattern is modified by shifting the sampling position for each slice, resulting in improvement of two-dimensional parallel imaging, as previously explained [8,13]. A previous study compared GRAPPA and CAIPIRINHA with various AFs in healthy volunteers [2].…”