Liposomal Gd-DTPA: effect of encapsulation on enhancement of hepatoma model by MRI.
Liposomes entrapping gadolinium-DTPA (Gd-DTPA) were synthesized from 60 mole percent egg phosphatidylcholine (EPC) and 40 mole percent cholesterol or EPC alone entrapping Gd-DTPA in diameters of 100 and 200 nm. Rats bearing Morris hepatoma in their flanks were imaged by MR pre- and post-contrast with free Gd-DTPA and liposomal Gd-DTPA for up to four hours after IV contrast. Comparison of images after free and liposomal Gd-DTPA showed dramatic differences in tumor and organ enhancement. Liposomal Gd-DTPA enhancement of tumor corresponded more closely to histologically proven vascularized portions of tumor than free Gd-DTPA. Hepatic enhancement was greater with liposomal than free Gd-DTPA and time course of liver, kidney and tumor enhancement was prolonged. The 100-nm EPC Gd-DTPA liposomes caused the greatest enhancement. Gd-DTPA liposomes may be useful as liver and blood pool contrast agents. By varying lipid composition and vesicle size, patterns of enhancement may be selectively modified.
Unger
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EC
Fox Chase Cancer Center, Department of Radiology, Philadelphia, PA 19111.
MacDougall
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Cullis
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Tilcock
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C
D000818:Animals; D003287:Contrast Media; D005069:Evaluation Studies as Topic; D005682:Gadolinium / Q000008:administration & dosage; D019786:Gadolinium DTPA; D008081:Liposomes; D008114:Liver Neoplasms, Experimental / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D009942:Organometallic Compounds / Q000008:administration & dosage; D004369:Pentetic Acid / Q000008:administration & dosage; D051381:Rats; D011916:Rats, Inbred F344
D003287:Contrast Media; D008081:Liposomes; D009942:Organometallic Compounds; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA