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Accuracy and reproducibility of blood clot burden quantification with pulmonary CT angiography. AJR Am J Roentgenol 2011; 196:516-23. [PMID: 21343492 DOI: 10.2214/ajr.10.4603] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE The purpose of our study was to assess the accuracy and reproducibility of clot burden quantification with pulmonary CT angiography (CTA). MATERIALS AND METHODS A semiautomated program was developed for segmentation and volumetric quantification of pulmonary embolus with pulmonary CTA. The accuracy of this measurement method was assessed using two pulmonary embolus phantoms. Reproducibility of the measurement method was assessed using clinical pulmonary CTA in 30 patients (16 women, 14 men; mean age, 62 years) with pulmonary embolism (PE). Two observers segmented and measured the volume of blood clot from pulmonary CTA images twice at two separate sessions. Accuracy was evaluated by the relative volume measurement error. Intra- and interobserver reliability were evaluated using intraclass correlation coefficient (ICC); agreement between measurements within and between the two observers was assessed using Bland-Altman analysis. RESULTS Mean relative measurement error from the two phantoms was less than 1% for both observers. A total of 60 emboli were measured from the 30 patients. The intraobserver ICC was 0.990 for observer 1 and 0.999 for observer 2; interobserver ICC was 0.994 for session 1 and 0.989 for session 2. ICC for all four clot measurements was 0.988. Mean volume measurement difference for intraobserver agreement was 0.9% for observer 1 and 0.3% for observer 2, and interobserver agreement was -5.1% for session 1 and -5.8% for session 2. CONCLUSION Blood clot burden can be quantified with a high degree of accuracy and reproducibility from pulmonary CTA images using a semiautomated segmentation method.
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Lanza GM, Winter PM, Caruthers SD, Hughes MS, Hu G, Schmieder AH, Wickline SA. Theragnostics for tumor and plaque angiogenesis with perfluorocarbon nanoemulsions. Angiogenesis 2010; 13:189-202. [PMID: 20411320 DOI: 10.1007/s10456-010-9166-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 03/24/2010] [Indexed: 10/19/2022]
Abstract
Molecular imaging agents are extending the potential of noninvasive medical diagnosis from basic gross anatomical descriptions to complicated phenotypic characterizations based upon the recognition of unique cell-surface biochemical signatures. Although originally the purview of nuclear medicine, "molecular imaging" is now studied in conjunction with all clinically relevant imaging modalities. Of the myriad of particles that have emerged as prospective candidates for clinical translation, perfluorocarbon nanoparticles offer great potential for combining targeted imaging with drug delivery, much like the "magic bullet" envisioned by Paul Ehrlich 100 years ago. Perfluorocarbon nanoparticles, once studied in Phase III clinical trials as blood substitutes, have found new life for molecular imaging and drug delivery. The particles have been adapted for use with all clinically relevant modalities and for targeted drug delivery. In particular, their intravascular constraint due to particle size provides a distinct advantage for angiogenesis imaging and antiangiogenesis therapy. As perfluorocarbon nanoparticles have recently entered Phase I clinical study, this review provides a timely focus on the development of this platform technology and its application for angiogenesis-related pathologies.
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Affiliation(s)
- G M Lanza
- Division of Cardiology, Department of Medicine, Washington University Medical School, 4320 Forest Park Ave, Suite 101, St. Louis, MO 63108, USA.
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Caruthers SD, Cyrus T, Winter PM, Wickline SA, Lanza GM. Anti-angiogenic perfluorocarbon nanoparticles for diagnosis and treatment of atherosclerosis. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2010; 1:311-23. [PMID: 20049799 DOI: 10.1002/wnan.9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Complementary developments in nanotechnology, genomics, proteomics, molecular biology and imaging offer the potential for early, accurate diagnosis. Molecularly-targeted diagnostic imaging agents will allow noninvasive phenotypic characterization of pathologies and, therefore, tailored treatment close to the onset. For atherosclerosis, this includes anti-angiogenic therapy with specifically-targeted drug delivery systems to arrest the development of plaques before they impinge upon the lumen. Additionally, monitoring the application and effects of this targeted therapy in a serial fashion will be important. This review covers the specific application of alpha(nu)beta(3)-targeted anti-angiogenic perfluorocarbon nanoparticles in (1) the detection of molecular markers for atherosclerosis, (2) the immediate verification of drug delivery with image-based prediction of therapy outcomes, and (3) the serial, noninvasive observation of therapeutic efficacy.
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Affiliation(s)
- Shelton D Caruthers
- Washington University School of Medicine and Philips Medical Systems, St. Louis, MO, USA.
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Díaz-López R, Tsapis N, Fattal E. Liquid perfluorocarbons as contrast agents for ultrasonography and (19)F-MRI. Pharm Res 2009; 27:1-16. [PMID: 19902338 DOI: 10.1007/s11095-009-0001-5] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2009] [Accepted: 10/22/2009] [Indexed: 12/22/2022]
Abstract
Perfluorocarbons (PFCs) are fluorinated compounds that have been used for many years in clinics mainly as gas/oxygen carriers and for liquid ventilation. Besides this main application, PFCs have also been tested as contrast agents for ultrasonography and magnetic resonance imaging since the end of the 1970s. However, most of the PFCs applied as contrast agents for imaging were gaseous. This class of PFCs has been recently substituted by liquid PFCs as ultrasound contrast agents. Additionally, liquid PFCs are being tested as contrast agents for (19)F magnetic resonance imaging (MRI), to yield dual contrast agents for both ultrasonography and (19)F MRI. This review focuses on the development and applications of the different contrast agents containing liquid perfluorocarbons for ultrasonography and/or MRI: large and small size emulsions (i.e. nanoemulsions) and nanocapsules.
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Affiliation(s)
- Raquel Díaz-López
- Univ Paris Sud, UMR CNRS 8612, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, 92296, Châtenay-Malabry, France
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Magadala P, van Vlerken LE, Shahiwala A, Amiji MM. Multifunctional Polymeric Nanosystems for Tumor-Targeted Delivery. MULTIFUNCTIONAL PHARMACEUTICAL NANOCARRIERS 2008. [DOI: 10.1007/978-0-387-76554-9_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Marsh JN, Partlow KC, Abendschein DR, Scott MJ, Lanza GM, Wickline SA. Molecular imaging with targeted perfluorocarbon nanoparticles: quantification of the concentration dependence of contrast enhancement for binding to sparse cellular epitopes. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:950-8. [PMID: 17434667 PMCID: PMC1978071 DOI: 10.1016/j.ultrasmedbio.2006.12.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 12/06/2006] [Accepted: 12/23/2006] [Indexed: 05/10/2023]
Abstract
Targeted, liquid perfluorocarbon nanoparticles are effective agents for acoustic contrast enhancement of abundant cellular epitopes (e.g., fibrin in thrombi) and for lower prevalence binding sites, such as integrins associated with tumor neovasculature. In this study, we sought to delineate the quantitative relationship between the extent of contrast enhancement of targeted surfaces and the density (and concentration) of bound perfluorocarbon (PFC) nanoparticles. Two dramatically different substrates were utilized for targeting. In one set of experiments, the surfaces of smooth, flat, avidin-coated agar disks were exposed to biotinylated nanoparticles to yield a thin layer of targeted contrast. For the second set of measurements, we targeted PFC nanoparticles applied in thicker layers to cultured smooth muscle cells expressing the transmembrane glycoprotein "tissue factor" at the cell surface. An acoustic microscope was used to characterize reflectivity for all samples as a function of bound PFC (determined via gas chromatography). We utilized a formulation of low-scattering nanoparticles having oil-based cores to compete against high-scattering PFC nanoparticles for binding, to elucidate the dependence of contrast enhancement on PFC concentration. The relationship between reflectivity enhancement and bound PFC content varied in a curvilinear fashion and exhibited an apparent asymptote (approximately 16 dB and 9 dB enhancement for agar and cell samples, respectively) at the maximum concentrations (approximately 150 microg and approximately 1000 microg PFOB for agar and cell samples, respectively). Samples targeted with only oil-based nanoparticles exhibited mean backscatter values that were nearly identical to untreated samples (<1 dB difference), confirming the oil particles' low-scattering behavior. The results of this study indicate that substantial contrast enhancement with liquid perfluorocarbon nanoparticles can be realized even in cases of partial surface coverage (as might be encountered when targeting sparsely populated epitopes) or when targeting surfaces with locally irregular topography. Furthermore, it may be possible to assess the quantity of bound cellular epitopes through acoustic means.
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MESH Headings
- Animals
- Cells, Cultured
- Contrast Media
- Emulsions
- Epitopes
- Female
- Fluorocarbons
- Hydrocarbons, Brominated
- Image Enhancement/methods
- Light
- Microscopy, Acoustic/methods
- Microscopy, Electron, Scanning/methods
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/diagnostic imaging
- Nanoparticles
- Nanotechnology/methods
- Scattering, Radiation
- Swine
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Affiliation(s)
- Jon N Marsh
- Center for Applied Nanomedicine, Department of Internal Medicine, Washington University, St. Louis, MO 63108, USA.
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Lanza G, Winter P, Cyrus T, Caruthers S, Marsh J, Hughes M, Wickline S. Nanomedicine Opportunities in Cardiology. Ann N Y Acad Sci 2006; 1080:451-65. [PMID: 17132801 DOI: 10.1196/annals.1380.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Despite myriad advances, cardiovascular-related diseases continue to remain our greatest health problem. In more than half of patients with atherosclerotic disease, their first presentation to medical attention becomes their last. Patients often survive their first cardiac event through acute revascularization and placement of drug-eluting stents (DES), but only select coronary lesions are amenable to DES placement, resulting in the use of bare metal or no stent, both of which lack the benefit of antirestenotic therapy. In other patients, transient ischemic attacks (TIAs) and stroke constitute the initial presentation of disease. In these patients, the diagnostic and therapeutic options are woefully inadequate. Nanomedicine offers options to each of these challenges. Antiangiogenic paramagnetic nanoparticles may be used to serially assess the severity of atherosclerotic disease in asymptomatic, high-risk patients by detecting the development of plaque neovasculature, which reflects the underlying lesion activity and vulnerability to rupture. The nanoparticles can locally deliver antiangiogenic therapy, which may acutely retard plaque progression, allowing aggressive statin therapy to become effective. Moreover, these agents may be useful as a quantitative marker to guide atherosclerotic management in an asymptomatic patient. In those cases proceeding to the catheterization laboratory for revascularization, nanoparticles incorporating antirestenotic drugs can be delivered directly into the wall of lesions not amenable to DES placement. Targeted nanoparticles could help ensure that antirestenotic drugs are available for all lesions. Moreover, displacement of antiproliferative agents from the intimal surface into the vascular wall is likely to improve rehealing of the endothelium, improving postprocedural management of these patients.
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Affiliation(s)
- Gregory Lanza
- Med and Biomed Engineering, School of Medicine, Washington University St. Louis, 4003 Kingshighway Bldg., St. Louis, MO 63130, USA.
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Couture O, Bevan PD, Cherin E, Cheung K, Burns PN, Foster FS. A model for reflectivity enhancement due to surface bound submicrometer particles. ULTRASOUND IN MEDICINE & BIOLOGY 2006; 32:1247-55. [PMID: 16875958 DOI: 10.1016/j.ultrasmedbio.2006.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2005] [Revised: 04/18/2006] [Accepted: 05/04/2006] [Indexed: 05/11/2023]
Abstract
Submicrometer particles filled with liquid perfluorocarbon have been shown to increase the ultrasound reflectivity of surfaces onto which they bind and, consequently, are seen as potential targeted contrast agents. The objective of this study is to explain the reflectivity enhancement as a result of the presence of randomly distributed particles on a surface. A model is presented where the diffraction-weighted scattering of all particles is summed over the exposed surface. Experiments were performed at frequencies ranging from 15 MHz to 60 MHz, with glass microbeads and perfluorohexane particles deposited on the surface of agar and Aqualene, a rubber closely matched to water, to confirm the validity of the model. Results showed that the model predicts the surface density and the frequency dependence of the reflectivity enhancement up to a density corresponding to twice the maximum packing of spheres on a surface (200% confluence fraction) for glass beads and a fifth (20% confluence fraction) for perfluorohexane particles. This suggests the possibility of predicting signal enhancement due to a bound contrast agent in simple geometries.
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Affiliation(s)
- Olivier Couture
- Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
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Dayton PA, Zhao S, Bloch SH, Schumann P, Penrose K, Matsunaga TO, Zutshi R, Doinikov A, Ferrara KW. Application of Ultrasound to Selectively Localize Nanodroplets for Targeted Imaging and Therapy. Mol Imaging 2006. [DOI: 10.2310/7290.2006.00019] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Hughes MS, Marsh JN, Hall CS, Fuhrhop RW, Lacy EK, Lanza GM, Wickline SA. Acoustic characterization in whole blood and plasma of site-targeted nanoparticle ultrasound contrast agent for molecular imaging. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2005; 117:964-72. [PMID: 15759715 DOI: 10.1121/1.1810251] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The ability to enhance specific molecular markers of pathology with ultrasound has been previously demonstrated by our group employing a nanoparticle contrast agent [Lanza et al., Invest. Radiol. 35, 227-234 (2000); Ultrasound Med. Biol. 23, 863-870 (1997)]. One of the advantages of this agent is very low echogenicity in the blood pool that allows increased contrast between the blood pool and the bound, site-targeted agent. We measured acoustic backscatter and attenuation coefficient as a function of the contrast agent concentration, ambient pressure, peak acoustic pressure, and as an effect of duty cycle and wave form shape. Measurements were performed while the nanoparticles were suspended in either whole porcine blood or plasma. The nanoparticles were only detectable when insonified within plasma devoid of red blood cells and were shown to exhibit backscatter levels more than 30 dB below the backscatter from whole blood. Attenuation of nanoparticles in whole porcine blood was not measurably different from that of whole blood alone over a range of concentrations up to eight times the maximum in vivo dose. The resulting data provide upper bounds on blood pool attenuation coefficient and backscatter and will be needed to more precisely define levels of molecular contrast enhancement that may be obtained in vivo.
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Affiliation(s)
- Michael S Hughes
- Washington University School of Medicine, Cardiovascular Division, St Louis, Missouri 63110, USA.
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Affiliation(s)
- Susannah H Bloch
- Department of Biomedical Engineering, University of California, Davis 95616, USA
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Abstract
Ultrasound has received less attention than other imaging modalities for molecular imaging, but has a number of potential advantages. It is cheap, widely available and portable. Using Doppler methods, flow information can be obtained easily and non-invasively. It is arguably the most physiological modality, able to image structure and function with less sedation than other modalities. This means that function is minimally disturbed, and multiple repeat studies or the effect of interventions can easily be assessed. High frame rates of over 200 frames a second are achievable on current commercial systems, allowing for convenient cardiac studies in small animals. It can be used to guide interventional or invasive studies, such as needle placement. Ultrasound is also unique in being both an imaging and therapeutic tool and its value in gene therapy has received much recent interest. Ultrasound biomicroscopy has been used for in utero imaging and can guide injection of virus and cells. Ultrahigh frequency ultrasound can be used to determine cell mechanical properties. The development of microbubble contrast agents has opened many new opportunities, including new functional imaging methods, the ability to image capillary flow and the possibility of molecular targeting using labelled microbubbles.
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Affiliation(s)
- H-D Liang
- Ultrasound Group, Imaging Sciences Department, Imperial College London, Clinical Sciences Centre, Hammersmith Campus, Du Cane Road, London W12 0HS, UK
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Marsh JN, Hall CS, Wickline SA, Lanza GM. Temperature dependence of acoustic impedance for specific fluorocarbon liquids. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2002; 112:2858-2862. [PMID: 12509007 DOI: 10.1121/1.1517251] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Recent studies by our group have demonstrated the efficacy of perfluorocarbon liquid nanoparticles for enhancing the reflectivity of tissuelike surfaces to which they are bound. The magnitude of this enhancement depends in large part on the difference in impedances of the perfluorocarbon, the bound substrate, and the propagating medium. The impedance varies directly with temperature because both the speed of sound and the mass density of perfluorocarbon liquids are highly temperature dependent. However, there are relatively little data in the literature pertaining to the temperature dependence of the acoustic impedance of these compounds. In this study, the speed of sound and density of seven different fluorocarbon liquids were measured at specific temperatures between 20 degrees C and 45 degrees C. All of the samples demonstrated negative, linear dependencies on temperature for both speed of sound and density and, consequently, for the acoustic impedance. The slope of sound speed was greatest for perfluorohexane (-278 +/- 1.5 cm/s-degrees C) and lowest for perfluorodichlorooctane (-222 +/- 0.9 cm/s-degrees C). Of the compounds measured, perfluorohexane exhibited the lowest acoustic impedance at all temperatures, and perfluorodecalin the highest at all temperatures. Computations from a simple transmission-line model used to predict reflectivity enhancement from surface-bound nanoparticles are discussed in light of these results.
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Affiliation(s)
- Jon N Marsh
- Washington University School of Medicine, Cardiovascular Division, 216 South Kingshighway, St. Louis, Missouri 63110, USA.
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Abstract
The discipline of medical imaging is expanding to include both traditional anatomic modalities and new techniques for the functional assessment of the presence and extent of disease. Current FDA-approved ultrasound contrast agents are micron-sized bubbles with a stabilizing shell. Microbubble contrast agents can be used to estimate microvascular flow rate in a manner similar to dynamic contrast-enhanced magnetic resonance imaging (MRI). The concentration of these agents within the vasculature, reticulo-endothelial, or lymphatic systems produces an effective passive targeting of these areas. Liquid-filled nanoparticles and liposomes have also demonstrated echogenicity and are under evaluation as ultrasound contrast agents. Actively targeted ultrasound relies on specially designed contrast agents to localize the targeted molecular signature or physiologic system. These agents typically remain within the vascular space, and therefore possible targets include molecular markers on thrombus, endothelial cells, and leukocytes. The purpose of this review is to summarize the requirements, challenges, current progress, and future directions of targeted imaging with ultrasound.
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Affiliation(s)
- Paul A Dayton
- Department of Biomedical Engineering, University of California-Davis, Davis, California 95616, USA
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