Skip Navigation LinksHome > February 2014 - Volume 49 - Issue 2 > Seven-Tesla Magnetic Resonance Imaging Accurately Quantifies...
Investigative Radiology:
doi: 10.1097/RLI.0b013e3182a7e1b7
Original Articles

Seven-Tesla Magnetic Resonance Imaging Accurately Quantifies Intratumoral Uptake of Therapeutic Nanoparticles in the McA Rat Model of Hepatocellular Carcinoma: Preclinical Study in a Rodent Model

Tyler, Patrick D. BA*‡; McDevitt, Joseph L. BA*‡; Sheu, Alexander Y. BS*‡; Nicolai, Jodi MS*; Procissi, Daniele PhD*; Ragin, Ann B. PhD*; Lewandowski, Robert J. MD; Salem, Riad MD; Larson, Andrew C. PhD*†§; Omary, Reed A. MD, MS

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Abstract

Objectives

After inducing McA tumors in Sprague-Dawley rats (McA-SD), the following hypotheses were tested: first, that hypervascular McA tumors grown in Sprague-Dawley rats provide a suitable platform to investigate drug delivery; and second, that high-field MRI can be used to measure intratumoral uptake of DOX-SPIOs.

Materials and Methods

McA cells were implanted into the livers of 18 Sprague-Dawley rats. In successfully inoculated animals, 220-μL DOX-SPIOs were delivered to tumors via the intravenous or intra-arterial route. Pretreatment and posttreatment T2*-weighted images were obtained using 7-T MRI, and change in R2* value (ΔR2*) was obtained from mean signal intensities of tumors in these images. Tumor iron concentration ([Fe]), an indicator of DOX-SPIO uptake, was measured using mass spectroscopy. The primary outcome variable was the Pearson correlation between ΔR2* and [Fe].

Results

Tumors grew successfully in 13 of the 18 animals (72%). Mean (SD) maximum tumor diameter was 0.83 (0.25) cm. The results of phantom studies revealed a strong positive correlation between ΔR2* and [Fe], with r = 0.98 (P < 0.01). The results of in vivo drug uptake studies demonstrated a positive correlation between ΔR2* and [Fe], with r = 0.72 (P = 0.0004).

Conclusions

The McA tumors grown in the Sprague-Dawley rats demonstrated uptake of nanoparticle-based therapeutic agents. Magnetic resonance imaging quantification of intratumoral uptake strongly correlated with iron concentrations in pathological specimens, suggesting that MRI may be used to quantify uptake of iron-oxide nanotherapeutics.

Copyright © 2014 by Lippincott Williams & Wilkins

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