Erin McKinstry, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: To describe a semi-automated technique for quantitative MRI spectral analysis of proton density (PD,) T1, and T2 distributions of the entire liver and spleen, using a mixed turbo spin echo (Mix TSE) pulse sequence in conjunction with quantitative MR image processing algorithms. Methods and Materials: Twenty adult subjects, including healthy volunteers (n=5), patients with biopsy-confirmed diffuse liver disease (n=5), and other in-patients (n = 10) were enrolled in this IRB-approved study (male=14, female=6, age range=29-76, mean age=46 years). MR images were acquired with the Mix TSE pulse sequence on a clinical 1.5T MR scanner. This dual-inversion/-echo time sequence was implemented with various scan settings; first TI's: 50-520 ms, second TI's: 1114-1791 ms, first TE's: 5.9-6.5 ms, second TE's: 100-200 ms. Fourteen to 28 axial slices (7.0-10.0 mm slice thickness, zero gap) were obtained for full anatomical coverage of the liver and spleen. Data was transferred to PC workstations where quantitative maps of T1, T2, and PD were computed with Q-MRI algorithms, and then further processed with semi-automated segmentation algorithms developed at our MR research lab for tissue characterization. PD, T1, and T2 distributions (representing the collection of all voxel values) were derived for the entire scanned volume, as well as for the whole segmented liver and spleen. Results: For each segmented organ/tissue type, uni-modal, semi-symmetrical distributions of PD (normalized to 1.0 for adipose fat), T1, and T2 values (respectively) were observed for all subjects. The peak location (mode) of these PD, T1, and T2 organ distributions ranged as follows: PD of liver: 0.38 to 0.68, T1 of liver: 280 to 451 ms, T2 of liver: 60 to 96 ms; PD of spleen: 0.34 to 0.76, T1 of spleen: 396 to 619 ms, T2 of spleen: 105 to 178 ms. Conclusion: A technique for whole organ characterization in terms of the Q-MRI spectral signatures is presented in a small cohort human study. Segmented organs and tissue types exhibit characteristic uni-modal Q-MRI spectra.      

McKinstry, E, Quantitative Magnetic Resonance Imaging (Q-MRI) Spectroscopy (PD, T1, and T2) of the Liver and Spleen: Whole Organ Characterization in 20 Patients.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3107049.html