A prototype 16-channel head Adaptive Image Receive (AIR) radiofrequency coil from GE Healthcare outperformed a conventional 8-channel head coil for in vivo whole-brain imaging, though it did not perform as well as a conventional 32-channel head coil, according to a recent article in ARRS’ American Journal of Roentgenology (AJR).
“This study shows the feasibility of the novel AIR coil technology for imaging the brain and provides insight for future coil design improvements,” concluded first author Petrice M. Cogswell of the Mayo Clinic in Rochester, Minnesota.
Lightweight and flexible with an open, ski-mask design, the emergent AIR coil technology exhibits electrical characteristics that overcome several of the limitations of traditional rigid coil designs.
CAPTION: Photograph shows participant positioned in balaclava AIR coil. Coil elements are sutured to external surface of fabric. In this prototype design, no elements are placed over patient’s eyes, nose, or mouth, which may improve comfort compared with conventional coils. In this image, identifiable portions of participant’s face have been obscured for publication and privacy purposes.
Imaging a phantom and 15 healthy adult participants, Cogswell and colleagues used clinically available MRI sequences to compare their 16-channel head AIR coil with conventional 8- and 32-channel head coils. During consensus review, two board-certified neuroradiologists graded the AIR coil against the 8-channel coil and the 32-channel coil on a 5-point ordinal scale in multiple categories.
On average, the signal-to-noise ratio, structural sharpness, and overall image quality scores of the 16-channel AIR coil prototype were better than those of the 8-channel coil but not as good as those of the 32-channel coil.
CAPTION: Magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) images of 25-year-old healthy female participant. A–C, MPRAGE images obtained with 8-channel (A), 16-channel AIR (B), and 32-channel (C) head coils. Surface coil intensity correction has been applied for these images via vendor-provided algorithm. Nonspecific white matter lesions and perivascular spaces (white arrow) evaluated for scoring of structural sharpness were better depicted on 32-channel relative to 16-channel AIR and on 16-channel relative to 8-channel coil. Frontal signal loss of 16-channel AIR coil is shown by red arrow in B. AIR coil element placement in this prototype was not specifically optimized for uniformity, and this may be improved in future designs.
Noise covariance matrices showed stable performance of the AIR coil across participants. Overall, the median g-factors for the 16-channel AIR coil were less than those of the 8-channel coil but greater than those of the 32-channel coil.
CAPTION: Noise covariance matrices from representative healthy 32-year-old female participant. Noise covariance matrices for 8-channel (left), 16-channel AIR (middle), and 32-channel (right) head coils. Noise power of each individual element is shown along diagonal, and noise correlation between elements is shown on off-diagonal. Off-diagonal terms are normalized to diagonal term, because relationship of off-diagonal to diagonal terms reflects coupling.
“The advantages of the AIR coil technology for reduction of claustrophobia, improved airway access and monitoring of patients under anesthesia, and overall better user comfort may be investigated in future studies,” the authors of this AJR article added.Back To Top
Adaptive Image Receive Coil from GE Shows Promise for Whole-Brain Imaging. Appl Radiol.