Akio Hiwatashi MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: The purpose of this study was to determine if it is possible to differentiate between the subcortical white matter of the primary auditory cortex (first Heschl gyrus (HG)) and the superior temporal gyrus (STG) by measuring the fractional anisotropy (FA) on diffusion tensor images (DTI) in healthy individuals. Methods and Materials: Six healthy volunteers (three males and three females), aged 26 to 41 years (mean 32 years) were included in this study. All MR examinations were performed on a GE Signa 1.5 T MR scanner. We used a single-shot pulsed-gradient spin-echo echo-planar sequence and the following parameters: repetition time = 1500 ms, echo time = 116 ms, matrix size = 256x256, field of view = 220x220 mm, total scan time = 6 min 28 sec. Diffusion weighting was applied in 20 orientations with b value 1000 s/mm2 in addition to 3 acquisitions at b=0 and was repeated 11 times in each orientation. Two 5 mm thick coronal slices were chosen to include HG. FA maps were generated with custom codes on off-line computer workstations (Sun and SGI). For quantitative analyses of these images, regions of interest consisting 3 x 3 pixels were placed in the subcortical white matters in HG and STG bilaterally. Results: The HG was detected on DTI in all volunteers. The mean ± standard deviation of fractional anisotropy was 0.37 ± 0.02 and 0.38 ± 0.01 in the subcortical white matter of the right and left HG and they were higher than that in ipsilateral STG (0.26 ± 0.02 and 0.28 ± 0.02 in the right and left STG, respectively). There were significant statistical differences between ipsilateral HG and STG (P = 0.002 and 0.005 for the right and the left side, respectively). There were no statistical differences in HG and STG compared to the contralateral side (P = 0.43 and 0.45 in HG and STG, respectively). Conclusion: In this study of normal volunteers we found the FA in the subcortical white matter of the HG to be higher than that of the STG in both hemispheres. The difference may be explained by the auditory radiation near the primary auditory cortex.       Questions about this event email: Akio Hiwatashi@urmc.rochester.edu

Hiwatashi MD, A, Diffusion Tensor Imaging of the Acoustic Radiation.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3101865.html