Image Quality Characteristics of the 3D-parallel Imaging Method (CAIPIRINHA) in Abdominal MRI.

This study investigated the image quality using controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) to shorten the imaging time in dynamic abdominal examinations. Comparisons with the conventional generalized autocalibrating partially parallel acquisitions (GRAPPA) method were made by changing the sampling shift in CAIPIRINHA using a 3.0 T MRI. The measurements included the visual evaluation of five stages, the signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in phantom experiments. The visual evaluation (five stages) and SNR were determined using a nickel sulfate bottle phantom attached to the MRI device. Each evaluation was performed on the middle slice of the 3D image. The SNR was compared with the mean region of interest value calculated from five locations within the phantom. The CNR was determined using custommade phantoms that mimic the T1 and T2 values of the liver and spleen. In the results, at reduction factor (Rf) = 6 and 8, the SNR per unit imaging time was reduced with GRAPPA, while there was no decrease in SNR and CNR with CAIPIRINHA. By performing imaging using an appropriate sampling shift, it is possible to acquire an equivalent GRAPPA in a short period of time using CAIPIRINHA.