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SU‐GG‐J‐153: Prolonged Discrimination of Target Structures in CT and MR‐Guided Therapies Using a Novel Contrast Agent
Author(s) -
Zheng J,
Allen C,
Jaffray D
Publication year - 2008
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2961702
Subject(s) - medicine , iohexol , nuclear medicine , liposome , lymph , contrast (vision) , gadolinium , voxel , spleen , magnetic resonance imaging , contouring , radiology , pathology , chemistry , biochemistry , organic chemistry , artificial intelligence , renal function , computer science , engineering drawing , engineering
Purpose: To evaluate the performance of a liposome‐based contrast agent in allowing for persistent discrimination of target and disease structures (tumor, invaded lymph nodes) using CT and MR imaging in tumor‐bearing rabbits following a single intravenous administration. Method and Materials: Five New Zealand White rabbits bearing VX2 sarcoma in their left lateral quadriceps received a single i.v. dose of liposomes (80 nm) encapsulating 250 μg/g of iodine in the form of iohexol and 15 μg/g of gadolinium in the form of gadoteridol. They were CT (80 kVp, 200 mA) and MR (3D FSPGR, TR/TE=9.8/4.3) imaged at 1 hour and 1, 2, 3, 5, 7, 10 and 14 days post contrast administration. Semi‐automated contouring using MicroView v2.2 allowed for generation of volumes of interest consisting of kidneys, spleen, liver, tumor and the contralateral muscle, which were subsequently used for data analysis. Results: Co‐localized accumulation and clearance of the liposome contrast agent is visually detected over a two‐week period in both CT and MR. In the tumor volumes, the mean HU increased following the administration of the contrast agent peaking at 3 days post‐injection, while the mean HU measured on the controlateral muscle volumes remained steady. Furthermore, the distribution of the liposome agent is highly heterogeneous within the tumor volume. For a representative rabbit at three days post‐injection, 29.6% of the tumor voxels measured between 115 and 290 HU. This liposome agent also proved to be able to target invaded lymph nodes (as confirmed by pathology). Specifically, 9 out of 10 iliac nodes from the 5 rabbits were enhanced. Conclusion: These investigations demonstrated the ability of nano‐sized liposomes encapsulating iohexol and gadoteridol to allow for persistent discrimination of disease structures and their potential for use in CT and MR‐guided therapies.