Feasibility of proton magnetic resonance spectroscopy for the assessment of chemotherapeutic drug delivery after TACE: a proof of concept

Abstract Purpose Proton magnetic resonance spectroscopy ( 1 H-MRS) is a spectroscopic method for the in-vivo assessment of various metabolites. The distribution and duration of intratumoral drug presence after transarterial chemoembolization (TACE) in liver malignancies is likely to affect treatment response. However, it may vary between different patients. The aim of this experimental work is to evaluate the feasibility of 1 H-MRS for treatment monitoring in TACE. Methods 1 H-MRS was performed (1) in-vitro and (2) ex-vivo in porcine liver using 2D single voxel spectroscopy with a preclinical 7 T MRI scanner. Doxorubicin, Embozene TANDEM® (Varian, Palo Alto, CA) beads and Lipiodol® (Guerbet, Villepinte, F), were examined in-vitro and ex-vivo. Data was analysed using a dedicated software. Results The main signal of doxorubicin, formed by a cycloalkyl- and methoxy group, was detected at 3.54 ± 0.02 ppm ex-vivo and 3.46 ± 0.04 ppm in-vitro (theoretical peak: 3.77 ppm). Embozene TANDEM® showed weak signals in the range from 1.04 ± 0.02 ppm to 3.60 ± 0.02 ppm in-vitro. Due to signal overlap, Embozene TANDEM® was only measurable in-vitro. Lipiodol® generated prominent signals in the range from 0.69 ± 0.02 ppm to 2.14 ± 0.03 ppm ex-vivo and 0.67 ± 0.02 ppm to 3.95 ± 0.04 ppm in-vitro, exceeding the signal strength of all other measured substances. Conclusion The spectrum of doxorubicin can be well separated from liver metabolites. Embozene TANDEM® has no interfering influence on the detection of doxorubicin. The strength of the Lipiodol® signal overlaps the signals of the liver. At 7 T 1 H-MRS appears to be suited for the in-vivo monitoring of drug delivery and distribution after TACE.