High sensitivity 19F MRI of a perfluorooctyl bromide emulsion: application to a dynamic biodistribution study and oxygen tension mapping in the mouse liver and spleen.
ABSTRACT We have recently developed an optimized multi-spin echo (MSE) sequence dedicated to perfluorooctyl bromide (PFOB) imaging yielding an excellent sensitivity in vitro. The aim of the present study was to apply this sequence to quantitative measurements in the mouse liver and spleen after intravenous (i.v.) injection of PFOB emulsions. We first performed oxygenation maps 25.5 min after a single infusion of emulsion and, contrary to previous studies, shortly after injection. The signal-to-noise ratio (SNR) in the liver and spleen was as high as 45 and 120, respectively, for 3-min images with 11.7-μL pixels. Values of oxygen tension tended to be slightly higher in the spleen than in the liver. Dynamic biodistribution experiments were then performed immediately after intravenous (i.v.) injection of PFOB emulsions grafted with different quantities of polyethylene glycol (PEG) for stealth. Images were acquired every 7 min for 84 min and the SNR measured in the liver and spleen was at least four from the first time point. Uptake rates could be assessed for each PEG amount and, in spite of high standard deviations (SDs) owing to interanimal variability, our data confirmed that increasing quantities of PEG allow more gradual uptake of the emulsion particles by the liver and spleen. In conclusion, our method seems to be a powerful tool to non-invasively perform accurate in vivo quantitative measurements in the liver and spleen using (19)F MRI.
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ABSTRACT: Fluorocarbons have been used for years as propellants in aerosol sprays. Because of their ability to transport oxygen, perfluorocarbon compounds have been more recently used in artificial fluid respiration. Monobrominated perfluorocarbon compounds are radiopaque and have low enough vapor pressures to be tolerated in biologic systems. Microemulsions of these compounds have been detected in mouse and rat neoplasms and appear to be located within macrophages. In this study of the potential usefulness of these compounds for radiographic contrast enhancement, rabbits with V2 carcinoma thigh implants received either a high-dose (10--12 ml/kg) or a low-dose (2 ml/kg) emulsion of perfluoroctylbromide intravenously. Dense contrast enhancement of some of the V2 carcinomas was demonstrated by both computed tomography and conventional radiography. Four of the five rabbits in the high-dose group died within 9 days but all six rabbits in the low-dose group survived beyond 9 days. Death in the high-dose group was associated with pulmonary consolidation and anesthesia although some animals had extensive V2 metastases. These compounds have some interesting potential applications in imaging, pending further study of their toxicity.American Journal of Roentgenology 08/1981; 137(1):141-6. · 2.90 Impact Factor
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ABSTRACT: Although perfluorochemicals (PFCs) are known for their ability to carry oxygen, they are the most versatile and only universal contrast agents with important applications using x-ray, ultrasound, or magnetic resonance (MR). The characteristics that make them unique diagnostic agents are lack of hydrogen atoms, immiscibility with water, low surface tension, compressibility, and long intravascular persistence when emulsified and given i.v. When made radiopaque, they are visible with x-ray computed tomography (CT) and standard radiography. Because the neat liquid is inert it can be ingested, instilled in the lung, or introduced into any hollow organ to image the lumen without untoward effects. The long intravascular persistence allows the imaging of blood vessels and vascularized tissues. Small or deep vessels become visible on Color Doppler Imaging and angiographic images of any vascular tree including the coronaries can be rendered from the serial CT images. As PFCs accumulate within RE cells, specific liver and spleen enhancement is achieved allowing the detection of small tumors within these organs. When injected interstitially, the particles find their way to the draining lymphnodes providing detail of the internal architecture to detect the presence or absence of tumor involvement on both CT and sonography. Using 19F MR, tissue perfusion and tissue pO2 measurements can be achieved. As can be seen, the applications of PFC in diagnosis are vast, unique, and important. These new capabilities will carry radiological tools to new horizons.Artificial Cells Blood Substitutes and Biotechnology 02/1994; 22(2):295-313. · 0.85 Impact Factor
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ABSTRACT: Perfluoroctylbromide (PFOB) in emulsion form was tested as a blood pool imaging agent for computed tomography (CT) in five animals (three dogs and two pigs). Computed tomography of the kidneys, liver, spleen, and mediastinum was performed in the control state and at various time intervals after the end of PFOB infusion. The attenuation coefficient of the vascular space increased by 117 Hounsfield units (HU) (range 105-128 HU), the liver by 54 HU (range 43-70 HU), and the spleen by 77 HU (range 69-86 HU) 30 to 50 min after the end of PFOB infusion, 5 ml/kg. The vascular space enhanced by 25 HU for every g of PFOB/100 ml of blood and remained at almost a constant level for hours after the end of infusion. In conclusion, PFOB emulsion, in addition to hepatosplenic enhancement, produces prolonged and substantial opacification of the vascular space, allowing CT imaging of the heart and vascular structures minutes to hours after the end of infusion.Journal of Computer Assisted Tomography 09/1984; 8(4):739-44. · 1.58 Impact Factor