Methods for diagnostic imaging by regulating the administration rate of contrast agent

Abstract

Methods for providing an image of an internal region of a patient. Embodiments of the methods involve administering to the patient a contrast agent which comprises a vesicle composition comprising, in an aqueous carrier, a gas or gaseous precursor and vesicles comprising lipids, proteins or polymers. The patient is scanned using diagnostic imaging, such as ultrasound, to obtain a visible image of the region. The contrast agent is administered to the patient at a rate to substantially eliminate diagnostic artifacts in the image. The methods are particularly useful for diagnosing the presence of any diseased tissue in the patient.

What is claimed is:  
     
         1 . A method for providing an image of an internal region of a patient comprising (i) administering to the patient a vesicle composition comprising, in an aqueous carrier, a gas or gaseous precursor and vesicles comprising lipids, proteins or polymers, and (ii) scanning the patient using diagnostic imaging to obtain a visible image of the region, wherein said vesicle composition is administered to the patient at a rate which substantially eliminates diagnostic artifacts in the image.  
     
     
         2 . A method according to  claim 1  wherein said vesicles comprise lipids.  
     
     
         3 . A method according to  claim 2  wherein said vesicle composition comprises vesicles selected from the group consisting of micelles and liposomes.  
     
     
         4 . A method according to  claim 2  wherein said lipids comprise phospholipids.  
     
     
         5 . A method according to  claim 4  wherein said phospholipids are selected from the group consisting of phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid.  
     
     
         6 . A method according to  claim 5  wherein said phosphatidylcholine is selected from the group consisting of dioleoylphosphatidylcholine, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine and distearoylphosphatidylcholine.  
     
     
         7 . A method according to  claim 6  wherein said phosphatidylcholine comprises dipalmitoylphosphatidylcholine.  
     
     
         8 . A method according to  claim 5  wherein said phosphatidylethanolamine is selected from the group consisting of dipalmitoylphosphatidylethanolamine, dioleoylphosphatidylethanolamine, N-succinyldioleoylphosphatidylethanolamine and 1-hexadecyl-2-palmitoylglycerophosphoethanolamine.  
     
     
         9 . A method according to  claim 8  wherein said phosphatidylethanolamine comprises dipalmitoylphosphatidylethanolamine.  
     
     
         10 . A method according to  claim 5  wherein said phosphatidic acid comprises dipalmitolylphosphatidic acid.  
     
     
         11 . A method according to  claim 2  wherein said lipid further comprises a polymer.  
     
     
         12 . A contrast agent according to  claim 11  wherein said polymer comprises a hydrophilic polymer.  
     
     
         13 . A method according to  claim 11  wherein said hydrophilic polymer comprises polyethylene glycol.  
     
     
         14 . A method according to  claim 1  wherein said vesicles comprise proteins.  
     
     
         15 . A method according to  claim 14  wherein said proteins comprise albumin.  
     
     
         16 . A method according to  claim 1  wherein said vesicles comprise polymers.  
     
     
         17 . A method according to  claim 16  wherein said polymers comprise synthetic polymers or copolymers which are prepared from monomers selected from the group consisting of acrylic acid, methacrylic acid, ethyleneimine, crotonic acid, acrylamide, ethyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, lactic acid, glycolic acid, ε-caprolactone, acrolein, cyanoacrylate, bisphenol A, epichlorhydrin, hydroxyalkylacrylates, siloxane, dimethylsiloxane, ethylene oxide, ethylene glycol, hydroxyalkylmethacrylates, N-substituted acrylamides, N-substituted methacrylamides, N-vinyl-2-pyrrolidone, 2,4-pentadiene-1-ol, vinyl acetate, acrylonitrile, styrene, p-amino-styrene, p-aminobenzylstyrene, sodium styrene sulfonate, sodium 2-sulfoxyethyl-methacrylate, vinyl pyridine, aminoethyl methacrylates and 2-methacryloyloxytrimethyl-ammonium chloride.  
     
     
         18 . A method according to  claim 16  wherein said polymers comprise synthetic polymers or copolymers selected from the group consisting of polyacrylic acid, polyethyleneimine, polymethacrylic acid, polymethylmethacrylate, polysiloxane, polydimethylsiloxane, polylactic acid, poly(ε-caprolactone), epoxy resin, poly(ethylene oxide), poly(ethylene glycol), polyamide, polyvinylidene-polyacrylonitrile, polyvinylidene-polyacrylonitrile-polymethylmethacrylate and polystyrene-polyacrylonitrile.  
     
     
         19 . A method according to  claim 18  wherein said polymers comprise polyvinylidene-polyacrylonitrile copolymer.  
     
     
         20 . A method according to  claim 1  wherein said gas comprises a fluorinated gas.  
     
     
         21 . A method according to  claim 20  wherein said fluorinated gas is selected from the group consisting of a perfluorocarbon, sulfur hexafluoride and heptafluoropropane.  
     
     
         22 . A method according to  claim 21  wherein said fluorinated gas comprises a perfluorocarbon.  
     
     
         23 . A method according to  claim 22  wherein said perfluorocarbon gas is selected from the group consisting of perfluoromethane, perfluoroethane, perfluoropropane, perfluorobutane and perfluorocyclobutane.  
     
     
         24 . A method according to  claim 1  wherein said gaseous precursor has a boiling point of greater than about 37° C.  
     
     
         25 . A method according to  claim 24  wherein said gaseous precursor comprises a fluorinated compound.  
     
     
         26 . A method according to  claim 25  wherein said fluorinated compound comprises a perfluorocarbon.  
     
     
         27 . A method according to  claim 26  wherein said perfluorocarbon is selected from the group consisting of perfluoropentane and perfluorohexane.  
     
     
         28 . A method according to  claim 1  wherein said diagnostic imaging is selected from the group consisting of ultrasound imaging and computed tomography imaging.  
     
     
         29 . A method according to  claim 28  wherein said diagnostic imaging comprises ultrasound imaging.  
     
     
         30 . A method according to  claim 1  wherein said internal region comprises the heart region.  
     
     
         31 . A method according to  claim 1  wherein said vesicle composition is administered to the patient at a rate of from about 1×10 6  to less than about 8×10 6  vesicles/Kg-sec.  
     
     
         32 . A method according to  claim 31  wherein said vesicle composition is administered at a rate of from about 1×10 6  to about 7×10 6  vesicles/Kg-sec.  
     
     
         33 . A method according to  claim 32  wherein said vesicle composition is administered at a rate of from about 1.5×10 6  to about 6×10 6  vesicles/Kg-sec.  
     
     
         34 . A method according to  claim 33  wherein said vesicle composition is administered at a rate of from about 2×10 6  to about 5.5×10 6  vesicles/Kg-sec.  
     
     
         35 . A method according to  claim 34  wherein said vesicle composition is administered at a rate of from about 2.5×10 6  to about 5×10 6  vesicles/Kg-sec.  
     
     
         36 . A method according to  claim 35  wherein said vesicle composition is administered at a rate of from about 3×10 6  to about 4.5×10 6  vesicles/Kg-sec.  
     
     
         37 . A method according to  claim 1  wherein said vesicle composition is administered to the patient at a rate of from about 1×10 −7  to about 3×10 −3  cc gas/Kg-sec.  
     
     
         38 . A method according to  claim 37  wherein said vesicle composition is administered at a rate of from about 3×10 −6  to about 3×10 −3  cc gas/Kg-sec.  
     
     
         39 . A method according to  claim 38  wherein said vesicle composition is administered at a rate of from about 4×10 −6  to about 2×10 −3  cc gas/Kg-sec.  
     
     
         40 . A method according to  claim 39  wherein said vesicle composition is administered at a rate of from about 8×10 −6  to about 2×10 −3  cc gas/Kg-sec.  
     
     
         41 . A method according to  claim 40  wherein said vesicle composition is administered at a rate of from about 1×10 −5  to about 1×10 −3  cc gas/Kg-sec.  
     
     
         42 . A method according to  claim 41  wherein said vesicle composition is administered at a rate of from about 4×10 −5  to about 1×10 −3  cc gas/Kg-sec.  
     
     
         43 . A method according to  claim 42  wherein said vesicle composition is administered at a rate of from about 8×10 −5  to less than about 1×10 −3  cc gas/Kg-sec.  
     
     
         44 . A method according to  claim 43  wherein said vesicle composition is administered at a rate of from about 1×10 −4  to about 9×10 −4  cc gas/Kg-sec.  
     
     
         45 . A method for providing an image of an internal region of a patient comprising (i) administering to the patient a lipid composition comprising, in an aqueous carrier, a lipid and a gas or gaseous precursor, and (ii) scanning the patient using diagnostic imaging to obtain a visible image of the region, wherein said lipid composition is administered to the patient at a rate which substantially eliminates diagnostic artifacts in the image.  
     
     
         46 . A method according to  claim 43  wherein said lipid comprises a phospholipid.  
     
     
         47 . A method according to  claim 46  wherein said phospholipid is selected from the group consisting of phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid.  
     
     
         48 . A method according to  claim 47  wherein said lipid composition comprises a vesicle composition.  
     
     
         49 . A method according to  claim 48  wherein said vesicle composition comprises vesicles selected from the group consisting of micelles and liposomes.  
     
     
         50 . A method according to  claim 45  wherein said diagnostic imaging is selected from the group consisting of ultrasound imaging and computed tomography imaging.  
     
     
         51 . A method according to  claim 50  wherein said diagnostic imaging comprises ultrasound imaging.  
     
     
         52 . A method according to  claim 45  wherein said lipid composition is administered to the patient at a rate of from about 1×10 −7  to about 3×10 −3  cc gas/Kg-sec.  
     
     
         53 . A method according to  claim 52  wherein said lipid composition is administered at a rate of from about 3×10 −6  to about 3×10 −3  cc gas/Kg-sec.  
     
     
         54 . A method according to  claim 53  wherein said lipid composition is administered at a rate of from about 4×10 −6  to about 2×10 −3  cc gas/Kg-sec.  
     
     
         55 . A method according to  claim 54  wherein said lipid composition is administered at a rate of from about 8×10 −6  to about 2×10 −3  cc gas/Kg-sec.  
     
     
         56 . A method according to  claim 55  wherein said lipid composition is administered at a rate of from about 1×10 −5  to about 1×10 −3  cc gas/Kg-sec.  
     
     
         57 . A method according to  claim 56  wherein said lipid composition is administered at a rate of from about 4×10 −5  to about 1×10 −3  cc gas/Kg-sec.  
     
     
         58 . A method according to  claim 57  wherein said lipid composition is administered at a rate of from about 8×10 −5  to less than about 1×10 −3  cc gas/Kg-sec.  
     
     
         59 . A method according to  claim 58  wherein said lipid composition is administered at a rate of from about 1×10 −4  to about 9×10 −4  cc gas/Kg-sec.  
     
     
         60 . A method for providing an image of an internal region of a patient comprising (i) administering to the patient a vesicle composition comprising, in an aqueous carrier, a gas or gaseous precursor and vesicles comprising lipids, proteins or polymers, (ii) flushing said composition, and (iii) scanning the patient using diagnostic imaging to obtain a visible image of the region, wherein said composition is flushed at a rate which substantially eliminates diagnostic artifacts in the image.  
     
     
         61 . A method accroding to  claim 60  wherein said vesicles comprise lipids.  
     
     
         62 . A method according to  claim 60  wherein said lipids comprise phospholipids.  
     
     
         63 . A method according to  claim 62  wherein said phospholipids are selected from the group consisting of phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid.  
     
     
         64 . A method according to  claim 63  wherein said phosphatidylcholine is selected from the group consisting of dioleoylphosphatidylcholine, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine and distearoylphosphatidylcholine.  
     
     
         65 . A method according to  claim 64  wherein said phosphatidylcholine comprises dipalmitoylphosphatidylcholine.  
     
     
         66 . A method according to  claim 63  wherein said phosphatidylethanolamine is selected from the group consisting of dipalmitoylphosphatidylethanolamine, dioleoylphosphatidylethanolamine, N-succinyldioleoylphosphatidylethanolamine and 1-hexadecyl-2-palmitoylglycerophosphoethanolamine.  
     
     
         67 . A method according to  claim 66  wherein said phosphatidylethanolamine comprises dipalmitoylphosphatidylethanolamine.  
     
     
         68 . A method according to  claim 63  wherein said phosphatidic acid comprises dipalmitolylphosphatidic acid.  
     
     
         69 . A method according to  claim 60  wherein said vesicles comprise proteins.  
     
     
         70 . A method according to  claim 69  wherein said proteins comprise albumin.  
     
     
         71 . A method according to  claim 60  wherein said vesicles comprise polymers.  
     
     
         72 . A method according to  claim 71  wherein said polymers comprise synthetic polymers or copolymers which are prepared from monomers selected from the group consisting of acrylic acid, methacrylic acid, ethyleneimine, crotonic acid, acrylamide, ethyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, lactic acid, glycolic acid, ε-caprolactone, acrolein, cyanoacrylate, bisphenol A, epichlorhydrin, hydroxyalkylacrylates, siloxane, dimethylsiloxane, ethylene oxide, ethylene glycol, hydroxyalkylmethacrylates, N-substituted acrylamides, N-substituted methacrylamides, N-vinyl-2-pyrrolidone, 2,4-pentadiene-1-ol, vinyl acetate, acrylonitrile, styrene, p-amino-styrene, p-aminobenzylstyrene, sodium styrene sulfonate, sodium 2-sulfoxyethyl-methacrylate, vinyl pyridine, aminoethyl methacrylates and 2-methacryloyloxytrimethyl-ammonium chloride.  
     
     
         73 . A method according to  claim 71  wherein said polymers comprise synthetic polymers or copolymers selected from the group consisting of polyacrylic acid, polyethyleneimine, polymethacrylic acid, polymethylmethacrylate, polysiloxane, polydimethylsiloxane, polylactic acid, poly(ε-caprolactone), epoxy resin, poly(ethylene oxide), poly(ethylene glycol), polyamide, polyvinylidene-polyacrylonitrile, polyvinylidene-polyacrylonitrile-polymethylmethacrylate and polystyrene-polyacrylonitrile.  
     
     
         74 . A method according to  claim 73  wherein said polymers comprise polyvinylidene-polyacrylonitrile copolymer.  
     
     
         75 . A method according to  claim 60  wherein said vesicle composition is flushed with a saline solution.  
     
     
         76 . A method according to  claim 60  wherein said gas comprises a fluorinated gas.  
     
     
         77 . A method according to  claim 76  wherein said fluorinated gas is selected from the group consisting of a perfluorocarbon gas, sulfur hexafluoride and heptafluoropropane.  
     
     
         78 . A method according to  claim 77  wherein said fluorinated gas comprises a perfluorocarbon.  
     
     
         79 . A method according to  claim 78  wherein said perfluorocarbon gas is selected from the group consisting of perfluoromethane, perfluoroethane, perfluoropropane, perfluorobutane and perfluorocyclobutane.  
     
     
         80 . A method according to  claim 60  wherein said gaseous precursor has a boiling point of greater than about 37° C.  
     
     
         81 . A method according to  claim 80  wherein said gaseous precursor comprises a fluorinated compound.  
     
     
         82 . A method according to  claim 81  wherein said fluorinated compound comprises a perfluorocarbon.  
     
     
         83 . A method according to  claim 82  wherein said perfluorocarbon is selected from the group consisting of perfluoropentane and perfluorohexane.  
     
     
         84 . A method according to  claim 61  wherein said vesicle composition comprises vesicles selected from the group consisting of micelles and liposomes.  
     
     
         85 . A method according to  claim 60  wherein said diagnostic imaging is selected from the group consisting of ultrasound imaging and computed tomography imaging.  
     
     
         86 . A method according to  claim 85  wherein said diagnostic imaging comprises ultrasound imaging.  
     
     
         87 . A method according to  claim 60  wherein said internal region comprises the heart region.  
     
     
         88 . A method according to  claim 60  wherein said vesicle composition is flushed at a rate of from about 0.01 to about 2.4 mL/sec.  
     
     
         89 . A method according to  claim 88  wherein said vesicle composition is flushed at a rate of from about 0.05 to about 2 mL/sec.  
     
     
         90 . A method according to  claim 89  wherein said vesicle composition is flushed at a rate of from about 0.07 to about 1.8 mL/sec.  
     
     
         91 . A method according to  claim 90  wherein said vesicle composition is flushed at a rate of from about 0.09 to about 1.6 mL/sec.  
     
     
         92 . A method according to  claim 91  wherein said vesicle composition is flushed at a rate of from about 0.1 to about 1.5 mL/sec.  
     
     
         93 . A method according to  claim 92  wherein said vesicle composition is flushed at a rate of from about 0.3 to about 1.3 mL/sec.  
     
     
         94 . A method according to  claim 93  wherein said vesicle composition is flushed at a rate of from about 0.5 to about 1.1 mL/sec.  
     
     
         95 . A method for providing an image of an internal region of a patient comprising (i) administering to the patient a lipid composition comprising, in an aqueous carrier, a lipid and a gas or gaseous precursor, (ii) flushing said composition, and (iii) scanning the patient using diagnostic imaging to obtain a visible image of the region, wherein said composition is flushed at a rate which substantially eliminates diagnostic artifacts in the image.  
     
     
         96 . A method according to  claim 95  wherein said lipid comprises a phospholipid.  
     
     
         97 . A method according to  claim 96  wherein said phospholipid is selected from the group consisting of phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid.  
     
     
         98 . A method according to  claim 97  wherein said lipid composition comprises a vesicle composition.  
     
     
         99 . A method according to  claim 95  wherein said vesicle composition comprises vesicles selected from the group consisting of micelles and liposomes.  
     
     
         100 . A method according to  claim 95  wherein said diagnostic imaging is selected from the group consisting of ultrasound imaging and computed tomography imaging.  
     
     
         101 . A method according to  claim 90  wherein said diagnostic imaging comprises ultrasound imaging.  
     
     
         102 . A method according to  claim 95  wherein said internal region comprises the heart region.  
     
     
         103 . A method according to  claim 95  wherein said composition is flushed at a rate of from about 0.01 to about 2.4 mL/sec.  
     
     
         104 . A method according to  claim 103  wherein said lipid composition is flushed at a rate of from about 0.05 to about 2 mL/sec.  
     
     
         105 . A method according to  claim 104  wherein said lipid composition is flushed at a rate of from about 0.07 to about 1.8 mL/sec.  
     
     
         106 . A method according to  claim 105  wherein said lipid composition is flushed at a rate of from about 0.09 to about 1.6 mL/sec.  
     
     
         107 . A method according to  claim 106  wherein said lipid composition is flushed at a rate of from about 0.1 to about 1.5 mL/sec.  
     
     
         108 . A method according to  claim 107  wherein said lipid composition is flushed at a rate of from about 0.3 to about 1.3 mL/sec.  
     
     
         109 . A method according to  claim 108  wherein said lipid composition is flushed at a rate of from about 0.5 to about 1.1 mL/sec.  
     
     
         110 . A method for substantially eliminating diagnostic artifacts in a diagnostic image of an internal region of a patient comprising regulating the rate at which a contrast agent is administered to the patient.  
     
     
         111 . A method according to  claim 110  wherein the diagnostic image is selected from the group consisting of ultrasound images and computed tomography images.  
     
     
         112 . A method according to  claim 111  wherein the diagnostic image comprises ultrasound images.  
     
     
         113 . A method according to  claim 110  wherein the diagnostic artifacts are selected from the group consisting of ultrasound artifacts and computed tomography artifacts.  
     
     
         114 . A method according to  claim 113  wherein the diagnostic artifacts comprise ultrasound artifacts.  
     
     
         115 . A method according to  claim 110  wherein said contrast agent comprises a vesicle composition comprising, in an aqueous carrier, a gas or gaseous precursor and vesicles comprising lipids, proteins or polymers.  
     
     
         116 . A method according to  claim 115  wherein said vesicles comprise lipids.  
     
     
         117 . A method according to  claim 116  wherein said vesicle composition comprises vesicles selected from the group consisting of micelles and liposomes.  
     
     
         118 . A method according to  claim 116  wherein said lipids comprise phospholipids.  
     
     
         119 . A method according to  claim 118  wherein said phospholipids are selected from the group consisting of phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid.  
     
     
         120 . A method according to  claim 119  wherein said phosphatidylcholine is selected from the group consisting of dioleoylphosphatidylcholine, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine and distearoylphosphatidylcholine.  
     
     
         121 . A method according to  claim 120  wherein said phosphatidylcholine comprises dipalmitoylphosphatidylcholine.  
     
     
         122 . A method according to  claim 119  wherein said phosphatidylethanolamine is selected from the group consisting of dipalmitoylphosphatidylethanolamine, dioleoylphosphatidylethanolamine, N-succinyldioleoylphosphatidylethanolamine and 1-hexadecyl-2-palmitoylglycerophosphoethanolamine.  
     
     
         123 . A method according to  claim 122  wherein said phosphatidylethanolamine comprises dipalmitoylphosphatidylethanolamine.  
     
     
         124 . A method according to  claim 119  wherein said phosphatidic acid comprises dipalmitolylphosphatidic acid.  
     
     
         125 . A method according to  claim 116  wherein said lipid further comprises a polymer.  
     
     
         126 . A contrast agent according to  claim 125  wherein said polymer comprises a hydrophilic polymer.  
     
     
         127 . A method according to  claim 126  wherein said hydrophilic polymer comprises polyethylene glycol.  
     
     
         128 . A method according to  claim 115  wherein said vesicles comprise proteins.  
     
     
         129 . A method according to  claim 128  wherein said proteins comprise albumin.  
     
     
         130 . A method according to  claim 115  wherein said vesicles comprise polymers.  
     
     
         131 . A method according to  claim 130  wherein said polymers comprise synthetic polymers or copolymers which are prepared from monomers selected from the group consisting of acrylic acid, methacrylic acid, ethyleneimine, crotonic acid, acrylamide, ethyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, lactic acid, glycolic acid, ε-caprolactone, acrolein, cyanoacrylate, bisphenol A, epichlorhydrin, hydroxyalkylacrylates, siloxane, dimethylsiloxane, ethylene oxide, ethylene glycol, hydroxyalkylmethacrylates, N-substituted acrylamides, N-substituted methacrylamides, N-vinyl-2-pyrrolidone, 2,4-pentadiene-1-ol, vinyl acetate, acrylonitrile, styrene, p-amino-styrene, p-aminobenzylstyrene, sodium styrene sulfonate, sodium 2-sulfoxyethyl-methacrylate, vinyl pyridine, aminoethyl methacrylates and 2-methacryloyloxytrimethyl-ammonium chloride.  
     
     
         132 . A method according to  claim 130  wherein said polymers comprise synthetic polymers or copolymers selected from the group consisting of polyacrylic acid, polyethyleneimine, polymethacrylic acid, polymethylmethacrylate, polysiloxane, polydimethylsiloxane, polylactic acid, poly(ε-caprolactone), epoxy resin, poly(ethylene oxide), poly(ethylene glycol), polyamide, polyvinylidene-polyacrylonitrile, polyvinylidene-polyacrylonitrile-polymethylmethacrylate and polystyrene-polyacrylonitrile.  
     
     
         133 . A method according to  claim 132  wherein said polymers comprise polyvinylidene-polyacrylonitrile copolymer.  
     
     
         134 . A method according to  claim 115  wherein said vesicle composition is administered to the patient at a rate of from about 1×10 6  to less than about 8×10 6  vesicles/Kg-sec.  
     
     
         135 . A method according to  claim 134  wherein said vesicle composition is administered at a rate of from about 1×10 6  to about 7×10 6  vesicles/Kg-sec.  
     
     
         136 . A method according to  claim 135  wherein said vesicle composition is administered at a rate of from about 1.5×10 6  to about 6×10 6  vesicles/Kg-sec.  
     
     
         137 . A method according to  claim 136  wherein said vesicle composition is administered at a rate of from about 2×10 6  to about 5.5×10 6  vesicles/Kg-sec.  
     
     
         138 . A method according to  claim 137  wherein said vesicle composition is administered at a rate of from about 2.5×10 6  to about 5×10 6  vesicles/Kg-sec.  
     
     
         139 . A method according to  claim 138  wherein said vesicle composition is administered at a rate of from about 3×10 6  to about 4.5×10 6  vesicles/Kg-sec.  
     
     
         140 . A method according to  claim 115  wherein said vesicle composition is administered to the patient at a rate of from about 1×10 −7  to about 3×10 −3  cc gas/Kg-sec.  
     
     
         141 . A method according to  claim 140  wherein said vesicle composition is administered at a rate of from about 3×10 −6  to about 3×10 −3  cc gas/Kg-sec.  
     
     
         142 . A method according to  claim 141  wherein said vesicle composition is administered at a rate of from about 4×10 −6  to about 2×10 −3  cc gas/Kg-sec.  
     
     
         143 . A method according to  claim 142  wherein said vesicle composition is administered at a rate of from about 8×10 −6  to about 2×10 −3  cc gas/Kg-sec.  
     
     
         144 . A method according to  claim 143  wherein said vesicle composition is administered at a rate of from about 1×10 −5  to about 1×10 −3  cc gas/Kg-sec.  
     
     
         145 . A method according to  claim 144  wherein said vesicle composition is administered at a rate of from about 4×10 −5  to about 1×10 −3  cc gas/Kg-sec.  
     
     
         146 . A method according to  claim 145  wherein said vesicle composition is administered at a rate of from about 8×10 −5  to less than about 1×10 −3  cc gas/Kg-sec.  
     
     
         147 . A method according to  claim 146  wherein said vesicle composition is administered at a rate of from about 1×10 −4  to about 9×10 −4  cc gas/Kg-sec.  
     
     
         148 . A method according to  claim 100  wherein said administration also comprises flushing said contrast agent.  
     
     
         149 . A method according to  claim 148  wherein said contrast agent is flushed at a rate of administered to the patient at a rate of from about 1×10 −7  to about 3×10 −3  cc gas/Kg-sec.  
     
     
         150 . A method according to  claim 149  wherein said contrast agent is flushed at a rate of from about 0.05 to about 2 mL/sec.  
     
     
         151 . A method according to  claim 150  wherein said contrast agent is flushed at a rate of from about 0.07 to about 1.8 mL/sec.  
     
     
         152 . A method according to  claim 151  wherein said contrast agent is flushed at a rate of from about 0.09 to about 1.6 mL/sec.  
     
     
         153 . A method according to  claim 152  wherein said contrast agent is flushed at a rate of from about 0.1 to about 1.5 mL/sec.  
     
     
         154 . A method according to  claim 153  wherein said contrast agent is flushed at a rate of from about 0.3 to about 1.3 mL/sec.  
     
     
         155 . A method according to  claim 154  wherein said contrast agent is flushed at a rate of from about 0.5 to about 1.1 mL/sec.  
     
     
         156 . A method according to  claim 100  wherein the region comprises the heart region.  
     
     
         157 . A method for diagnosing the presence of diseased tissue in a patient comprising (i) administering to the patient a vesicle composition comprising, in an aqueous carrier, a gas or gaseous precursor and vesicles comprising lipids, proteins or polymers, and (ii) scanning the patient using diagnostic imaging to obtain a visible image of any diseased tissue in the patient, wherein said vesicle composition is administered to the patient at a rate which substantially eliminates diagnostic artifacts in said image.  
     
     
         158 . A method for diagnosing the presence of diseased tissue in a patient comprising (i) administering to the patient a lipid composition comprising, in an aqueous carrier, a lipid and a gas or gaseous precursor, and (ii) scanning the patient using diagnostic imaging to obtain a visible image of any diseased tissue in the patient, wherein said lipid composition is administered to the patient at a rate which substantially eliminates diagnostic artifacts in said image.  
     
     
         159 . A method for diagnosing the presence of diseased tissue in a patient comprising (i) administering to the patient a vesicle composition comprising, in an aqueous carrier, a gas or gaseous precursor and vesicles comprising lipids, proteins or polymers, (ii) flushing said composition, and (iii) scanning the patient using diagnostic imaging to obtain a visible image of any diseased tissue in the patient, wherein said vesicle composition is flushed at a rate which substantially eliminates diagnostic artifacts in the image.  
     
     
         160 . A method for diagnosing the presence of diseased tissue in a patient comprising (i) administering to the patient a lipid composition comprising, in an aqueous carrier, a lipid and a gas or gaseous precursor, (ii) flushing said composition, and (iii) scanning the patient using diagnostic imaging to obtain a visible image of any diseased tissue in the patient, wherein said lipid composition is flushed at a rate which substantially eliminates diagnostic artifacts in the image.  
     
     
         161 . A system for administering a contrast agent to a patient comprising: 
 (a) a first vessel containing a contrast agent;    (b) a second vessel containing a flushing agent;    (c) a conduit having means for directing fluid into a blood vessel of the patient;    (d) means for placing said first and second vessels into flow communication with said conduit;    (e) first flow inducing means for inducing said contrast agent to flow from said first vessel into said conduit; and    (f) second flow inducing means for inducing said flushing agent to flow from said second vessel into said conduit subsequent to said flowing of said contrast agent into said conduit by said first flow inducing means.    
     
     
         162 . A system according to  claim 161  wherein said second flow inducing means further comprises means for inducing said contrast agent to flow from said conduit into said blood vessel and for subsequently inducing said flushing agent to flow from said conduit into said blood vessel.  
     
     
         163 . A system according to  claim 162  wherein said second flow inducing means has means for inducing flow at variable rates, whereby said contrast agent flows into said blood vessel at a first rate and said flushing agent flows into said blood vessel at a second rate.  
     
     
         164 . A system according to  claim 161  wherein said first flow inducing means comprises a syringe plunger and said first vessel comprises a syringe barrel in which said plunger slides.  
     
     
         165 . A system according to  claim 161  wherein said second flow inducing means comprises a mechanical injector.  
     
     
         166 . A system according to  claim 165  wherein said mechanical injector operates using pneumatic or hydraulic pressure.  
     
     
         167 . A system according to  claim 161  wherein said conduit comprises a needle.  
     
     
         168 . A system according to  claim 161  wherein said conduit comprises tubing.  
     
     
         169 . A system according to  claim 161  wherein said means for placing said first and second vessels into flow communication with said conduit comprises a three-way stopcock.  
     
     
         170 . A system according to  claim 161  wherein said means for placing said first and second vessels into flow communication with said conduit comprises a port.  
     
     
         171 . A system according to  claim 161  wherein said contrast agent comprises a vesicle composition comprising, in an aqueous carrier, a gas or gaseous precursor and vesicles comprising lipids, proteins or polymers.  
     
     
         172 . A system according to  claim 161  wherein said contrast agent comprises a lipid composition comprising, in an aqueous carrier, a lipid and a gas or gaseous precursor.  
     
     
         173 . A system according to  claim 161  wherein said flushing agent comprises a saline solution.