Chemical Shift MR Imaging Methods for the Quantification of Transcatheter Lipiodol Delivery to the Liver: Preclinical Feasibility Studies in a Rodent Model

Abstract

Purpose:To demonstrate the feasibility of using chemical shift magnetic resonance (MR) imaging fat-water separation methods for quantitative estimation of transcatheter lipiodol delivery to liver tissues. Materials and Methods:Studies were performed in accordance with institutional Animal Care and Use Committee guidelines. Proton nuclear MR spectroscopy was first performed to identify lipiodol spectral peaks and relative amplitudes. Next, phantoms were constructed with increasing lipiodol-water volume fractions. A multiecho chemical shift-based fatwater separation method was used to quantify lipiodol concentration within each phantom. Six rats served as controls; 18 rats underwent catheterization with digital subtraction angiography guidance for intraportal infusion of a 15%, 30%, or 50% by volume lipiodol-saline mixture. MR imaging measurements were used to quantify lipiodol delivery to each rat liver. Lipiodol concentration maps were reconstructed by using both single-peak and multipeak chemical shift models. Intraclass and Spearman correlation coefficients were calculated for statistical comparison of MR imaging-based lipiodol concentration and volume measurements to reference standards (known lipiodol phantom compositions and the infused lipiodol dose during rat studies). Results:Both single-peak and multipeak measurements were well correlated to phantom lipiodol concentrations (r 2 . 0.99). Lipiodol volume measurements were progressively and significantly higher when comparing between animals receiving different doses (P , .05 for each comparison). MR imaging-based lipiodol volume measurements strongly correlated with infused dose (intraclass correlation coefficients . 0.93, P , .001) with both single-and multipeak approaches. Conclusion:Chemical shift MR imaging fat-water separation methods can be used for quantitative measurements of lipiodol delivery to liver tissues.q RSNA, 2012

A multifunctional contrast dye for morphological research

“…Proton ( 1 H) NMR spectroscopy revealed that the spectrums of both native LPD and newly formulated RIO were almost identical ( Fig. 1B) and similar to that previously reported for LPD (Yin, 2012).…”

Characterization and Evaluation of Injectable Biodegradable Polymer Multimodality Radiologic Markers in an In Vivo Murine Model

“…However, the signals in its 1 H NMR spectrum can be used to identify its presence in the polymer clips. The characteristic peaks at 0.96 ppm, 2.25 ppm, and 4.27 ppm have been used to distinguish Lipiodol from the polymers in the clip formulation . NMR analysis of the markers also confirmed the presence of Lipiodol remaining in the samples after 6 months.…”

“…The characteristic peaks at 0.96 ppm, 2.25 ppm, and 4.27 ppm have been used to distinguish Lipiodol from the polymers in the clip formulation. 16 NMR analysis of the markers also confirmed the presence of Lipiodol remaining in the samples after 6 months. However, 1 H NMR splitting of the polymer and Lipiodol could not be determined in the marker samples because of excess dissolved tissue samples along with iron oxide nanoparticles.…”

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

“…A few studies have reported that this new technology makes it possible to discriminate the signals obtained in Lipiodol accumulation in HCCs [20][21][22] . In the present study, we therefore investigated whether chemical-shift MRI could be used to evaluate the signal derived from Lipiodol accumulation in HCCs after Lp-TACE.…”