ABSTRACT
To investigate the clinical value of 1H magnetic resonance spectroscopy (1H MRS) in the evaluation of high intensity focused ultrasound (HIFU) ablation for primary liver cancer. Routine magnetic resonance sequences, contrast-enhanced magnetic resonance imaging and respiratory-triggered single voxel point resolved spectroscopy sequence (PRESS) were performed on 24 patients with primary liver cancer before and after HIFU ablation. A respiratory-triggered axial T2 weighted imaging (T2WI) was used as localizer for PRESS. Spectroscopy data was transmitted to a personal computer and was post-processed with a custom software (Saker, provided by Ning Jing, an engineer in GE Healthcare). It would be considered "technical success" if the baselines of spectra were stable and main metabolites were without overlapping and could be identified. Integral areas of choline (Cho) peak at 3.2 parts per million (ppm) and lipid (Lip) peak at 1.3 ppm were measured, and the choline to lipid (Cho/Lip) ratios were calculated. The differences of areas of Cho, Lip peak and Cho/Lip ratios before and after HIFU ablation were compared by using paired samples t test, and a P value of less than 0.05 was considered statistically significant. The technical success rate of 1H-MRS was 87.50% (42/48). Integral areas of Cho peak and Lip peak of 20 patients with satisfied spectra were measured, and the Cho/Lip ratios were calculated. The Integral area of Cho peak decreased from 34 597+/-6 802 before HIFU ablation to 6 372+/-2 466 after HIFU ablation (t = 18.02, P less than 0.01). The Integral area of Lip peak increased from 147 948+/-16 317 before HIFU ablation to 149 069+/-16 345 after HIFU ablation (t = -15.11, P less than 0.01). The Cho/Lip ratio decreased from 0.23+/-0.03 before HIFU ablation to 0.04+/-0.02 after HIFU ablation (t = 25.32, P less than 0.01). 1H-MRS could provide information of metabolites changes of primary liver cancer after HIFU ablation and could be used as a complementary sequence to other magnetic resonance sequences to evaluate all around primary liver cancer after HIFU ablation.
ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the application of 3D liver acquisition volume acceleration (3D-LAVA) integrated with array spatial sensitivity encoding technique (ASSET) in liver dynamic-enhancement scanning.</p><p><b>METHODS</b>One hundred forty-seven patients underwent conventional plain and contrast enhancement liver MR imaging. 3D-LAVA and 2D fast spoiled gradient recalled echo were used for contrast enhancement liver MR scanning in 90 and 57 patients respectively. In the 3D-LAVA group, integrated ASSET was used in 72 out of the 90 patients. Of the 57 patients who underwent examinations using 2D fast spoiled gradient recalled echo, portal vein CE-MRA was performed on 20. The ability of 3D-LAVA to detect the lesions and the advantage to shorten the acquisition time after integrating with ASSET were analyzed. Original images of 60 patients in the 3D-LAVA group were processed using MIP to illustrate the anatomy of the portal vein. They were compared with those shown by CE-MRA to evaluate the illustration abilities of the two approaches.</p><p><b>RESULTS</b>3D-LAVA is more sensitive than 2D-FSPGR in detecting metastatic hepatic carcinomas. In the 3D-LAVA group integrated with ASSET, earlier and peak arterial phase images were acquired in 34 cases; and earlier, peak and late arterial phase images were acquired in 23 cases. The illustrations of the portal vein anatomy by 3D-LAVA were similar to those shown by portal vein CE-MRA.</p><p><b>CONCLUSION</b>3D-LAVA integrated with ASSET can obtain higher quality multi-phase dynamic enhancement images of the liver in a shorter time, and in the meantime also shows the vascular anatomy.</p>