Soman Salil, Holdsworth Samantha J, Skare Stefan, Andre Jalal B, Van Anh T, Aksoy Murat, Bammer Roland, Rosenberg Jarrett, Barnes Patrick D, Yeom Kristen W
Department of Radiology, Stanford University, Stanford, CA.
Department of Radiology, Lucas Center, Stanford University, Stanford, CA.
J Neuroimaging. 2015 Mar-Apr;25(2):296-302. doi: 10.1111/jon.12093. Epub 2014 Mar 5.
Diffusion tensor imaging (DTI) is useful for multiple clinical applications, but its routine implementation for children may be difficult due to long scan times. This study evaluates the impact of decreasing the number of DTI acquisitions (NEX) on interpretability of pediatric brain DTI.
15 children with MRI-visible neuropathologies were imaged at 3T using our motion-corrected, parallel imaging- accelerated DT-EPI technique with 3 NEX (scan time 8.25 min). Using these acquisitions, NEX = 1 (scan time 2.75 min) and NEX = 2 (scan time 5.5 min) images were simulated. Two neuroradiologists scored diffusion-weighted images (DWI), apparent diffusion coefficient (ADC), fractional anisotropy (FA), and first eigenvector color-encoded (EV) images from each NEX for perceived SNR, lesion conspicuity and clinical confidence. ROI FA/ADC and image SNR values were also compared across NEX.
NEX = 2 perceived SNR, lesion conspicuity, and clinical confidence were not inferior to NEX = 3 images. NEX = 1 images showed comparable lesion conspicuity and clinical confidence as NEX = 3, but inferior perceived SNR. FA and ADC ROI measurements demonstrated no significant difference across NEX. The greatest SNR increase was seen between NEX = 1 and NEX = 2.
Reducing NEX to shorten imaging time may impact clinical utility in a manner that does not directly correspond with SNR changes.
