Method of magnetic resonance imaging of the liver and spleen
First Claim
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1. The method of imaging a tumor in the liver or spleen of a human subject, comprising:
- (a) parenterally administering to the human subject prior to magnetic resonance imaging (MRI) examination an aqueous suspension composed essentially of 1.5 to 8 micron diameter microspheres, said microspheres having a biodegradeable matrix with a contrast agent dispersed therein selected from the group consisting of paramagnetic and ferromagnetic contrast agents, the quantity of said microspheres administered being effective to appreciably reduce the T2 relaxation time of the subject'"'"'s liver and/or spleen;
(b) delaying the examination until the microspheres have been segregated by the reticuloendothelial system and are concentrated in the liver and spleen; and
then(c) carrying out an MRI examinaiton of the liver and/or spleen by T2 imaging or mixed T1 and T2 imaging to obtain an image in which the normal liver or spleen tissues appear dark and the tumor appears light with distinct margins therebetween.
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Abstract
A method of magnetic resonance imaging (MRI) of liver and/or spleen is provided employing encapsulated contrast agents in the form of microspheres having a biodegradeable matrix with the paramagnetic/ferromagnetic contrast agent dispersed therein. Ferromagnetic contrast agents such as magnetite are preferred. Ferromagnetic microspheres when administered intravenously segregate through the reticuloendothelial system in the liver and spleen where they reduce the T2 relaxation time to obtain improved MR imaging.
101 Citations
14 Claims
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1. The method of imaging a tumor in the liver or spleen of a human subject, comprising:
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(a) parenterally administering to the human subject prior to magnetic resonance imaging (MRI) examination an aqueous suspension composed essentially of 1.5 to 8 micron diameter microspheres, said microspheres having a biodegradeable matrix with a contrast agent dispersed therein selected from the group consisting of paramagnetic and ferromagnetic contrast agents, the quantity of said microspheres administered being effective to appreciably reduce the T2 relaxation time of the subject'"'"'s liver and/or spleen; (b) delaying the examination until the microspheres have been segregated by the reticuloendothelial system and are concentrated in the liver and spleen; and
then(c) carrying out an MRI examinaiton of the liver and/or spleen by T2 imaging or mixed T1 and T2 imaging to obtain an image in which the normal liver or spleen tissues appear dark and the tumor appears light with distinct margins therebetween. - View Dependent Claims (2, 3, 4, 5, 6)
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7. The method of imaging a tumor in the liver or spleen of a human subject, comprising:
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(a) intravenously administering to the human subject prior to magnetic resonance imaging (MRI) examination an aqeuous suspension composed essentially of microspheres having an average size of from 2 to 5 microns diameter, said microspheres being composed of a biodegradable matrix having a ferromagnetic contrast agent dispersed therein, the quantity of said microspheres administered being effective to appreciably reduce the T2 relaxation time of the subject'"'"'s liver and/or spleen; (b) delaying the examination until the microspheres have been segregated by the reticuloendothelial system and are concentrated in the liver and spleen; and
then(c) carrying out an MRI examination of the liver and/or spleen by T2 imaging or mixed T1 and T2 imaging to obtain an image in which the normal liver or spleen tissues appear dark and the tumor appears light with distinct margins therebetween. - View Dependent Claims (8, 9, 10, 11)
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12. The method of imaging a tumor in the liver or spleen of a human subject, comprising:
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(a) intravenously administering to the human subject prior to magnetic resonance imaging (MRI) examination an aqueous suspension composed essentially of 1.5 to 8 micron diameter microspheres, said microspheres having a matrix of human serum albumin with magnetite particles dispersed therein, the quantity of said micropsheres administered being effective to appreciably reduce the T2 relaxation time of the subject'"'"'s liver and/or spleen; (b) delaying the examination until the microspheres have been segregated by the reticuloendothelial system and are concentrated in the liver and spleen; and
then(c) carrying out an MRI examination of the liver and/or spleen by T2 imaging or mixed T1 and T2 imaging to obtain an image in which the normal liver or spleen tissues appear dark and the tumor appears light with distinct margins therebetween. - View Dependent Claims (13, 14)
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Specification