Chemical-shift Magnetic Resonance Imaging Performed after Chemoembolization of Hepatocellular Carcinoma

Abstract

: We investigated whether the Lipiodol-derived signal accumulated in hepatocellular carcinoma HCC after transcatheter arterial chemoembolization TACE using Lipiodol oil-based contrast agent mixed with an anticancer agent, known as Lp-TACE, could be evaluated with chemical-shift magnetic resonance imaging MRI . The subjects were 25 HCC patients n 45 tumors who had undergone Lp-TACE and chemical-shift MRI of the abdominal region from April 1, 2000 to March 31, 2012. The regions of interest ROIs were set as large as possible to include the Lipiodol accumulation region on computed tomography CT images and the hyperintense signal region in double-echo fast low-angle shot FLASH , automatic-subtracted images on MRI. We then used both modalities to measure the CT value and signal intensity for each specimen. The MRI signal intensity was calculated by subtracting the background signal intensity from the measured value. The mean CT value for the 45 tumors in the 25 patients of 710 Houns eld units HU ; range, 139-3,062 HU was positively correlated with the mean MRI signal intensity of 43.5 0-212 . Tumors with a diameter ≥ 2 cm exhibited a stronger correlation between CT values and MRI signal intensity in areas of Lipiodol accumulation than tumors smaller than 2 cm. A weaker correlation was observed between the CT values and MRI signal intensity in areas of Lipiodol accumulation when the period from Lp-TACE to MRI was shorter than a week compared to one week or over. Our ndings suggest that chemical-shift MRI can detect Lipiodol accumulation in HCCs and could therefore be useful in evaluating such types of accumulation.

Automatic contrast medium extraction system using electron density data with dual-energy CT

“…Miyagami, et al reported that the range of the CT numbers in the Lipiodol region in HCC patients were 139 to 3062 HU. 11 From the result of the correlation of the CT numbers and the contrast medium concentration in Figure 5, 3000 HU was over 90 mg ml −1 concentration of the contrast medium using over 100 kV. Thus, the contrast medium extraction method is needed to be evaluate at 90 mg ml −1 concentration of the contrast medium.…”