[O-2-175] Identification of Heschl's gyrus on phase difference enhanced imaging
Background and objective: Human primary auditory cortex locates on the superior surface of the temporal lobe in the region known as Heschl’s gyrus (HG). A previous study at 7T evaluated the T2* signal-intensity (SI) of the HG cortex. However, no studies have analyzed the signal intensity of the white matter (WM) in the HG. The phase difference enhanced (PADRE) imaging was developed to enhance the contrast between the target tissue and surrounding tissue by choosing the appropriate phase difference. On PADRE images, the SI of a certain WM may reflect its myelin content. Our purpose is to evaluate relative SI of the WM in the HG on PADRE images in comparison with the SWI-like images.Materials and Methods: The subjects comprised four healthy volunteers (8 sides, 2 women, 2 men: mean age 29.0 years: range 28-30 years). Coronal high-spatial-resolution PADRE images were acquired covering the entire HG and superior temporal gyrus (STG) using a 3T MR system. By consensus of two observers, the HG and STG were identified based on previously established anatomic methods. The SI of WM in the HG on the PADRE images and SWI-like images were divided into three grades in comparison with that of the STG; grade I: isointense, grade II: slightly hypointense, and grade III: markedly hypointense. Results: For the SI of WM, the grade II and grade III appearances were found in 3 (38%) and 5 (62%) of 8 HG (4 subjects) on PADRE images, respectively. On the other hand, all 8 HG were rated as grade I on SWI-like images, suggesting that there was no difference of susceptibility between the HG and STG. Conclusion: The WM in the HG shows hypointense on PADRE, which probably reflects the higher myelin content. PADRE may be useful for identification of the HG by assessing the SI of the WM.