High-Resolution Magnetic Resonance Imaging Using Compressed Sensing for Intracranial and Extracranial Arteries: Comparison with Conventional Parallel Imaging.

OBJECTIVE: To compare conventional sensitivity encoding (SENSE) to compressed sensing plus SENSE (CS) for high-resolution magnetic resonance imaging (HR-MRI) of intracranial and extracranial arteries.

MATERIALS AND METHODS: HR-MRI was performed in 14 healthy volunteers. Three-dimensional T1-weighted imaging (T1WI) and proton density-weighted imaging (PD) were acquired using CS or SENSE under the same total acceleration factors (AFt )-5.5, 6.8, and 9.7 for T1WI and 3.2, 4.0, and 5.8 for PD-to achieve reduced scanning times in comparison with the original imaging sequence (SENSE T1WI, AFt 3.5; SENSE PD, AFt 2.0) using the 3-tesla system. Two neuroradiologists measured signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), and used visual scoring systems to assess image quality. Acceptable imaging was defined as a visual score ≥ 2. Repeated measures analysis of variance and Cochran's Q test were performed.

RESULTS: CS yielded better image quality and vessel delineation than SENSE in T1WI with AFt of 5.5, 6.8, and 9.7, and in PD with AFt of 5.8 ( p < 0.05). CS T1WI with AFt of 5.5 and CS PD with AFt of 3.2 and 4.0 did not differ significantly from original imaging ( p > 0.05). SNR and CNR in CS were higher than they were in SENSE, but lower than they were in the original images ( p < 0.05). CS yielded higher proportions of acceptable imaging than SENSE (CS T1WI with AFt of 6.8 and PD with AFt of 5.8; p < 0.0167).

CONCLUSION: CS is superior to SENSE, and may be a reliable acceleration method for vessel HR-MRI using AFt of 5.5 for T1WI, and 3.2 and 4.0 for PD.