title: Highly accelerated T1-weighted abdominal imaging using 2-dimensional controlled aliasing in parallel imaging results in higher acceleration: a comparison with generalized autocalibrating partially parallel acquisitions parallel imaging.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the feasibility and technical quality of an abdominal 3-dimensional interpolated breath-hold (volumetric interpolated breath-hold examination [VIBE]) magnetic resonance examination using the new parallel acquisition technique, controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA).
  
  
  METHODS
  In this institutional review board-approved study, 15 volunteers underwent an abdominal magnetic resonance imaging examination including axial unenhanced 3-dimensional VIBE sequences with the conventional parallel acquisition technique, generalized autocalibrating partially parallel acquisitions parallel imaging (GRAPPA), with an acceleration factor (R) of 2, 3, 4, and 2 × 2 in comparison with a CAIPIRINHA-VIBE sequence with an acceleration factor of 2 × 2. Images were evaluated regarding the overall image quality, liver edge sharpness, and parallel imaging artifacts. Signal-to-noise ratio was evaluated using 2 different methods. In a second study population, 17 patients were examined with our new routine protocol for abdominal imaging that now comprises VIBE sequences with CAIPIRINHA with R = 2 × 2.
  
  
  RESULTS
  In the volunteer population, the overall image quality of CAIPIRINHA with R = 2 × 2 was significantly higher compared with GRAPPA with R = 3, 4, and 2 × 2 (P < 0.05). There were significantly less parallel imaging artifacts with CAIPIRINHA with R = 2 × 2 (P < 0.05). Acquisition time varied between 21.1 (GRAPPA with R = 2, 320 matrix) and 6.9 seconds (CAIPIRINHA with R = 2 × 2, 256 matrix). Signal-to-noise ratio performance of CAIPIRINHA with R = 2 × 2 was superior to GRAPPA with R = 3, 4, and 2 × 2. In the patient population, VIBE sequences with CAIPIRINHA with R = 2 × 2 showed consistently good image quality, minimal motion artifacts, and minimal parallel imaging artifacts.
  
  
  CONCLUSIONS
  The CAIPRINHA-VIBE with an acceleration factor of R = 2 × 2 is feasible in a clinical setting and is characterized by fast and robust imaging with an image quality comparable with a 2-fold acceleration with GRAPPA.
authors: Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany. Philipp.Riffel@umm.de
authors: Philipp
authors: P
authors: Riffel
authors: Ulrike I
authors: UI
authors: Attenberger
authors: Stephan
authors: S
authors: Kannengiesser
authors: Marcel D
authors: MD
authors: Nickel
authors: Carolyn
authors: C
authors: Arndt
authors: Mathias
authors: M
authors: Meyer
authors: Stefan O
authors: SO
authors: Schoenberg
authors: Henrik J
authors: HJ
authors: Michaely
mesh_terms: D000005:Abdomen / Q000473:pathology*; D000328:Adult; D000368:Aged; D000465:Algorithms; D016477:Artifacts; D002138:Calibration; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult