Review

Nanotechnology and MRI contrast enhancement

Department of Chemistry and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, TX 77005, USA.

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Email the corresponding author at durango@rice.edu

Lon J Wilson

† Author for correspondence

Department of Chemistry and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, TX 77005, USA.

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Email the corresponding author at durango@rice.edu

Published Online:17 Mar 2010https://doi.org/10.4155/fmc.10.3

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Abstract

Technical advances in nanotechnology are creating novel classes of MRI contrast-enhancing agents. These nanomaterials offer much higher relaxivities than most current clinical contrast agents, which translates into greater MRI contrast enhancement. These nanoscale agents also have the potential to revolutionize in vivo applications of contrast-enhanced MRI since they offer the multiple advantages of low toxicities, extremely high relaxivities and cell internalization capabilities. In this review, we discuss three types of such contrast agents currently in use or under development for medical imaging: small particles of iron oxide, fullerenes encapsulating Gd³⁺ ions (gadofullerenes) and single-walled carbon nanotube nanocapsules encapsulating Gd³⁺ ion clusters (gadonanotubes). The latest developments and projected future applications of these nanotechnology-inspired contrast agents in the field of medical imaging are also discussed.

Papers of special note have been highlighted as: ▪ of interest ▪▪ of considerable interest

Bibliography

1 Leff HS, Rex AF. Maxwell’s demon 2: entropy, classical and quantum information, computing Institute of Physics, Bristol, PA, USA (2003).Google Scholar
2 Muller EW. Study of atomic structure of metal surfaces in the field ion microscope. J. Appl. Phys.28,1–6 (1957).Crossref, CAS, Google Scholar
3 Eigler DM, Schweizer EK. Positioning single atoms with a scanning tunneling microscope. Nature344,524–526 (1990).Crossref, CAS, Google Scholar
4 Ferrari M. Cancer nanotechnology: opportunities and challenges. Nat. Rev. Cancer5,161–171 (2005).Crossref, Medline, CAS, Google Scholar
5 Hartman KB, Laus S, Bolskar RD et al. Gadonanotubes as ultrasensitive pH-smart probes for magnetic resonance imaging. Nano. Lett.8,415–419 (2008).Crossref, Medline, CAS, Google Scholar
6 Hämisch Y. Molecular Imaging with PET: new insights into the molecular basis of health and disease. Medicamundi47,18–27 (2003).Google Scholar
7 Månsson SB. Physical principles of magnetic imaging by nuclear magnetic resonance. In: The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging. Merbach A, Toth E (Eds). John Wiley & Sons, Chichester, UK, 1–43 (2001).▪▪ Provides the physical principles of MRI by describing NMR phenomena and their relaxation processes in detail.Google Scholar
8 de Bazelaire CM, Duhamel GD, Rofsky NM, Alsop DC. MR imaging relaxation times of abdominal and pelvic tissues measured in vivo at 3.0 T: preliminary results. Radiology230,652–659 (2004).Crossref, Medline, Google Scholar
9 Hendrick RE, Haacke EM. Basic physics of MR contrast agents and maximization of image-contrast. J. Magn. Reson. Imaging3,137–148 (1993).▪ Explains the physical basis of MRI contrast agents.Crossref, Medline, CAS, Google Scholar
10 Bean CP, Livingston JD. Superparamagnetism. J. Appl. Phys.30,120–129 (1959).Crossref, Google Scholar
11 Cacheris WP, Quay SC, Rocklage SM. The relationship between thermodynamics and the toxicity of gadolinium complexes. Magn. Reson. Imaging8,467–481 (1990).Crossref, Medline, CAS, Google Scholar
12 Olsvik O, Popovic T, Skjerve E et al. Magnetic separation techniques in diagnostic microbiology. Clin. Microbiol. Rev.7,43–54 (1994).Crossref, Medline, CAS, Google Scholar
13 Månsson S. Physical principles of magnetic imaging by nuclear magnetic resonance. In: The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging. Merbach A, Toth E (Eds). Wiley, NY, USA, 1–43 (2001).Google Scholar
14 Bulte JWM, Kraitchman DL. Iron oxide MR contrast agents for molecular and cellular imaging. NMR Biomed.17,484–499 (2004).▪▪ Describes the use of SPIOs for molecular imaging, cell labeling, cell migration and trafficking and imaging of macrophage activity.Crossref, Medline, CAS, Google Scholar
15 Liu W, Frank JA. Detection and quantification of magnetically labeled cells by cellular MRI. Eur. J. Radiol.70,258–264 (2009).Crossref, Medline, Google Scholar
16 Ferrucci JT, Stark DD. Iron-oxide enhanced MR-imaging of the liver and spleen – review of the 1st–5 years. Am. J. Roentgenol.155,943–950 (1990).Crossref, Medline, CAS, Google Scholar
17 Pratten MK, Lloyd JB. Pinocytosis and phagocytosis – the effect of size of a particulate substrate on its mode of capture by rat peritoneal-macrophages cultured in vitro. Biochim. Biophys. Acta881,307–313 (1986).Crossref, Medline, CAS, Google Scholar
18 Rogers WJ, Basu P. Factors regulating macrophage endocytosis of nanoparticles: implications for targeted magnetic resonance plaque imaging. Atherosclerosis178,67–73 (2005).Crossref, Medline, CAS, Google Scholar
19 Weissleder R, Stark DD, Engelstad BL et al. Superparamagnetic iron-oxide - pharmacokinetics and toxicity. Am. J. Roentgenol.152,167–173 (1989).▪ Establishes the pharmacokinetics and toxicity of dextran-coated ferumoxide superparamagnetic iron oxide nanoparticles and concludes that the material is a biocompatible potential MRI contrast agent.Crossref, Medline, CAS, Google Scholar
20 Saini S, Stark DD, Hahn PF et al. Ferrite particles – a superparamagnetic MR contrast agent for enhanced detection of liver-carcinoma. Radiology162,217–222 (1987).Crossref, Medline, CAS, Google Scholar
21 Lu AH, Salabas EL, Schuth F. Magnetic nanoparticles: Synthesis, protection, functionalization, and application. Angew. Chem. Int. Ed. Engl.46,1222–1244 (2007).Crossref, Medline, CAS, Google Scholar
22 Patri A, Dobrovolskaia M, Stern S, McNeil S. Preclinical characterization of engineered nanoparticles intended for cancer therapeutics. In: Nanotechnology for cancer therapy. Amiji MM (Ed.). CRC/Taylor & Francis, Boca Raton, USA, 817 (2007).Google Scholar
23 Stark DD, Weissleder R, Elizondo G et al. Superparamagnetic iron-oxide – clinical-application as a contrast agent for MR imaging of the liver. Radiology168,297–301 (1988).Crossref, Medline, CAS, Google Scholar
24 Reimer P, Balzer T. Ferucarbotran (Resovist): a new clinically approved RES-specific contrast agent for contrast-enhanced MRI of the liver: properties, clinical development, and applications. Eur. Radiol.13,1266–1276 (2003).Crossref, Medline, Google Scholar
25 Gruttner C, Teller J. New types of silica-fortified magnetic nanoparticles as tools for molecular biology applications. J. Magn. Magn. Mater.194,8–15 (1999).Crossref, CAS, Google Scholar
26 Taupitz M, Wagner S, Schnorr J. Phase I clinical evaluation of citrate-coated monocrystalline very small superparamagnetic iron oxide particles as a new contrast medium for magnetic resonance imaging. Invest. Radiol.39,625–625 (2004).Crossref, CAS, Google Scholar
27 Li W, Tutton S, Vu AT et al. First-pass contrast-enhanced magnetic resonance angiography in humans using ferumoxytol, a novel ultrasmall superparamagnetic iron oxide (USPIO)-based blood pool agent. J. Magn. Reson. Imaging21,46–52 (2005).Crossref, Medline, Google Scholar
28 Schulze E, Ferrucci JT, Poss K, Lapointe L, Bogdanova A, Weissleder R. Cellular uptake and trafficking of a prototypical magnetic iron-oxide label in-vitro. Invest. Radiol.30,604–610 (1995).Crossref, Medline, CAS, Google Scholar
29 Huang HC, Chang PY, Chang K et al. Formulation of novel lipid-coated magnetic nanoparticles as the probe for in vivo imaging. J. Biomed. Sci.16(1),86 (2009).Crossref, Medline, Google Scholar
30 Kim D, Hong KS, Song J. The present status of cell tracking methods in animal models using magnetic resonance imaging technology. Mol. Cell23,132–137 (2007).CAS, Google Scholar
31 Vogl TJ, Hammerstingl R, Schwarz W et al. Superparamagnetic iron oxide-enhanced versus gadolinium-enhanced MR imaging for differential diagnosis of focal liver lesions. Radiology198,881–887 (1996).Crossref, Medline, CAS, Google Scholar
32 Zheng WW, Zhou KR, Chen ZW, Shen JZ, Chen CZ, Zhang SJ. Characterization of focal hepatic lesions with SPIO-enhanced MRI. World J. Gastroenterol.8,82–86 (2002).Crossref, Medline, Google Scholar
33 Harisinghani MG, Saini S, Weissleder R et al. MR lymphangiography using ultrasmall superparamagnetic iron oxide in patients with primary abdominal and pelvic malignancies: radiographic-pathologic correlation. Am. J. Roentgenol.172,1347–1351 (1999).Crossref, Medline, CAS, Google Scholar
34 Michel SCA, Keller TM, Frohlich JM et al. Preoperative breast cancer staging: MR imaging of the axilla with ultrasmall superparamagnetic iron oxide enhancement. Radiology225,527–536 (2002).Crossref, Medline, Google Scholar
35 Lee JM, Kim IH, Kwak HS, Youk JH, Han YM, Kim CS. Detection of small hypervascular hepatocellular carcinomas in cirrhotic patients: comparison of superparamagnetic iron oxide-enhanced MR imaging with dual-phase spiral CT. Korean J. Radiol.4,1–8 (2003).Crossref, Medline, Google Scholar
36 Tanimoto A, Wakabayashi G, Shinmoto H, Nakatsuka S, Okuda S, Kuribayashi S. Superparamagnetic iron oxide-enhanced MR imaging for focal hepatic lesions: a comparison with CT during arterioportography plus CT during hepatic arteriography. J. Gastroenterol.40,371–380 (2005).Crossref, Medline, Google Scholar
37 Nakamura H, Ito N, Kotake F, Mizokami Y, Matsuoka T. Tumor-detecting capacity and clinical usefulness of SPIO-MRI in patients with hepatocellular carcinoma. J. Gastroenterol.35,849–855 (2000).Crossref, Medline, CAS, Google Scholar
38 Kudo M. Imaging diagnosis of hepatocellular carcinoma and premalignant/borderline lesions. Semin. Liver Dis.19,297–309 (1999).Crossref, Medline, CAS, Google Scholar
39 Araki T. SPIO-MRI in the detection of hepatocellular carcinoma. J. Gastroenterol.35,874–876 (2000).Crossref, Medline, CAS, Google Scholar
40 Rappeport ED, Loft A, Berthelsen AK et al. Contrast-enhanced FDG-PET/CT vs. SPIO-enhanced MRI vs. FDG-PET vs. CT in patients with liver metastases from colorectal cancer: a prospective study with intraoperative confirmation. Acta Radiol.48,369–378 (2007).Crossref, Medline, CAS, Google Scholar
41 Rogers WJ, Meyer CH, Kramer CM. Technology insight: in vivo cell tracking by use of MRI. Nat. Clin. Pract. Cardiovasc. Med.3,554–562 (2006).Crossref, Medline, CAS, Google Scholar
42 Krejci J, Pachernik J, Hampl A, Dvorak P. In vitro labelling of mouse embryonic stem cells with SPIO nanoparticles. Gen. Physiol. Biophys.27,164–173 (2008).Medline, CAS, Google Scholar
43 Gao J. MRI-visible micellar nanomedicine for targeted drug delivery to lung cancer cells. Mol. Pharm.7(1),32–40 (2010).Crossref, Medline, Google Scholar
44 Huang H, Xie Q, Kang M et al. Labeling transplanted mice islet with polyvinylpyrrolidone coated superparamagnetic iron oxide nanoparticles for in vivo detection by magnetic resonance imaging. Nanotechnology20,365101 (2009).Crossref, Medline, Google Scholar
45 Mulder WJM, Strijkers GJ, van Tilborg GAF, Griffioen AW, Nicolay K. Lipid-based nanoparticles for contrast-enhanced MRI and molecular imaging. NMR Biomed.19,142–164 (2006).Crossref, Medline, CAS, Google Scholar
46 Tang Z, Lin N, Fang H et al. MRI tracking of the fate of intravascularly injected and SPIO-labeled rat mesenchymal stem cells in the livers of rats with hepatic fibrosis. Dig. Dis. Sci. DOI: 10.1007/s10620-009-0921-2 (2009) (Epub ahead of print).Google Scholar
47 Sykova E, Jendelova P. In vivo tracking of stem cells in brain and spinal cord injury. Prog. Brain Res.161,367–383 (2007).Crossref, Medline, CAS, Google Scholar
48 Nowacek A, Gendelman HE. NanoART, neuroAIDS and CNS drug delivery. Nanomed.4,557–574 (2009).Crossref, Medline, CAS, Google Scholar
49 Toma A, Otsuji E, Kuriu Y et al. Monoclonal antibody A7-superparamagnetic iron oxide as contrast agent of MR imaging of rectal carcinoma. Br. J. Cancer93,131–136 (2005).Crossref, Medline, CAS, Google Scholar
50 Tsourkas A, Shinde-Patil VR, Kelly KA et al.In vivo imaging of activated endothelium using an anti-VCAM-1 magnetooptical probe. Bioconjug. Chem.16,576–581 (2005).Crossref, Medline, CAS, Google Scholar
51 Bos C, Delmas Y, Desmouliere A et al.In vivo MR imaging of intravascularly injected magnetically labeled mesenchymal stem cells in rat kidney and liver. Radiology233,781–789 (2004).Crossref, Medline, Google Scholar
52 Frank JA, Miller BR, Arbab AS et al. Clinically applicable labeling of mammalian and stem cells by combining superparamagnetic iron oxides and transfection agents. Radiology229,610–610 (2003).Crossref, Medline, Google Scholar
53 Kawahara I, Nakamoto M, Kitagawa N et al. Potential of magnetic resonance plaque imaging using superparamagnetic particles of iron oxide for the detection of carotid plaque. Neurol. Med. Chir. (Tokyo)48,157–162 (2008).Crossref, Medline, Google Scholar
54 Marzelli M, Fischer K, Kim YB et al. Composite MR contrast agents for conditional cell-labeling. Int. J. Imaging Syst. Technol.18,79–84 (2008).Crossref, Medline, Google Scholar
55 Yang F, Gu AY, Chen ZP, Gu N, Ji M. Multiple emulsion microbubbles for ultrasound imaging. Mater. Lett.62,121–124 (2008).Crossref, CAS, Google Scholar
56 Ji XJ, Shao RP, Elliott AM et al. Bifunctional gold nanoshells with a superparamagnetic iron oxide-silica core suitable for both MR imaging and photothermal therapy. J. Phys. Chem. C Nanomater. Interfaces111,6245–6251 (2007).Crossref, Medline, CAS, Google Scholar
57 Stuber M, Gilson WD, Schar M et al. Positive contrast visualization of iron oxide-labeled stem cells using inversion-recovery with ON-Resonant water suppression (IRON). Magn. Reson. Med.58,1072–1077 (2007).Crossref, Medline, Google Scholar
58 Zurkiya O, Hu XP. Off-resonance saturation as a means of generating contrast with superparamagnetic nanoparticles. Magn. Reson. Med.56,726–732 (2006).Crossref, Medline, Google Scholar
59 Kroto HW, Heath JR, Obrien SC, Curl RF, Smalley RE. C-60 – buckminsterfullerene. Nature318,162–163 (1985).Crossref, CAS, Google Scholar
60 Heath JR, Obrien SC, Zhang Q et al. Lanthanum complexes of spheroidal carbon shells. J. Am. Chem. Soc.107,7779–7780 (1985).Crossref, CAS, Google Scholar
61 Laus S, Sitharaman B, Toth E et al. Understanding paramagnetic relaxation phenomena for water-soluble gadofullerenes. J. Phys. Chem. C Nanomater. Interfaces111,5633–5639 (2007).▪▪ Explores the mechanisms (inner-sphere and outer-sphere) that give gadofullerenes their high-performance efficacy as an MRI contrast agent.Crossref, CAS, Google Scholar
62 Toth E, Bolskar RD, Borel A et al. Water-soluble gadofullerenes: Toward high-relaxivity, pH-responsive MRI contrast agents. J. Am. Chem. Soc.127,799–805 (2005).▪▪ Establishes the efficacy and pH dependence of water-soluble gadofullerenes for use as MRI contrast media.Crossref, Medline, CAS, Google Scholar
63 Bertini I, Galas O, Luchinat C, Parigi G. Computer-program for the calculation of paramagnetic enhancements nuclear-relaxation rates in slowly rotating systems. J. Magn. Reson. A113,151–158 (1995).Crossref, CAS, Google Scholar
64 Laus S, Sitharaman B, Toth V et al. Destroying gadofullerene aggregates by salt addition in aqueous solution of Gd@C₆₀(OH)_x and Gd@C₆₀[C(COOH₂)]₁₀. J. Am. Chem. Soc.127,9368–9369 (2005).Crossref, Medline, CAS, Google Scholar
65 Sitharaman B, Tran LA, Pham QP et al. Gadofullerenes as nanoscale magnetic labels for cellular MRI. Contrast Media Mol. Imaging2,139–146 (2007).Crossref, Medline, CAS, Google Scholar
66 Stevenson S, Stephen RR, Amos TM, Cadorette VR, Reid JE, Phillips JP. Synthesis and purification of a metallic nitride fullerene BisAdduct: exploring the reactivity of Gd₃N@C₈₀. J. Am. Chem. Soc.127,12776–12777 (2005).Crossref, Medline, CAS, Google Scholar
67 Lu J, Sabirianov RF, Mei WN, Gao Y, Duan CG, Zeng XC. Structural and magnetic properties of Gd₃N@C₈₀. J. Phys. Chem. B.110,23637–23640 (2006).Crossref, Medline, CAS, Google Scholar
68 Stevenson S, Phillips JP, Reid JE, Olmstead MM, Rath SP, Balch AL. Pyramidalization of Gd3N inside a C-80 cage. The synthesis and structure of Gd₃N@C₈₀. Chem. Commun.2814–2815 (2004).Crossref, Medline, Google Scholar
69 MacFarland DK, Walker KL, Lenk RP et al. Hydrochalarones: a novel endohedral metallofullerene platform for enhancing magnetic resonance imaging contrast. J. Med. Chem.51,3681–3683 (2008).Crossref, Medline, CAS, Google Scholar
70 Chen Z, Fatouros PP, Corwin FD, Broaddus WC, Dorn HC. In vitro and in vivo imaging studies of a new gadolinium endohedral metallofullerene MRI contrast agent. Neuro. Oncol.8,492–492 (2006).Google Scholar
71 Fatouros PP, Corwin FD, Chen ZJ et al.In vitro and in vivo imaging studies of a new endohedral metallofullerene nanoparticle. Radiology240,756–764 (2006).Crossref, Medline, Google Scholar
72 Rinzler AG, Liu J, Dai H et al. Large-scale purification of single-wall carbon nanotubes: process, product, and characterization. Appl. Phys. A Mater. Sci. Processing67,29–37 (1998).Crossref, CAS, Google Scholar
73 Journet C, Maser WK, Bernier P et al. Large-scale production of single-walled carbon nanotubes by the electric-arc technique. Nature388,756–758 (1997).Crossref, CAS, Google Scholar
74 Nikolaev P, Bronikowski MJ, Bradley RK et al. Gas-phase catalytic growth of single-walled carbon nanotubes from carbon monoxide. Chem. Phys. Lett.313,91–97 (1999).Crossref, CAS, Google Scholar
75 Gu Z, Peng H, Hauge RH, Smalley RE, Margrave JL. Cutting single-wall carbon nanotubes through fluorination. Nano. Lett.2,1009–1013 (2002).Crossref, CAS, Google Scholar
76 Ashcroft JM, Hartman KB, Kissell KR et al. Single-molecule I-2@US tube nanocapsules: a new X-ray contrast-agent design. Adv. Mater.19,573 (2007).Crossref, CAS, Google Scholar
77 Hartman KB, Hamlin DK, Wilbur DS, Wilson LJ. (AtCl)-At-211@US tube nanocapsules: a new concept in radiotherapeutic-agent design. Small3,1496–1499 (2007).Crossref, Medline, CAS, Google Scholar
78 Sitharaman B, Kissell KR, Hartman KB et al. Superparamagnetic gadonanotubes are high-performance MRI contrast agents. Chem. Commun.3915–3917 (2005).▪▪ Establishes the gadonanotube as a novel nanotechnology and describes their high-performance efficacy as an MRI contrast agent.Crossref, Medline, Google Scholar
79 Ananta JS, Matson ML, Tang AM et al. Single-walled carbon nanotubes materials as T²-weighted MRI contrast agents. J. Phys. Chem. C DOI: 10.1021/jp907891n (2009) (Epub ahead of print).Google Scholar
80 Sithararman B, Wilson LJ. Gadonanotubes as new high-performance MRI contrast agents. Int. J. Nanomed.1,291–295 (2006).Medline, Google Scholar
81 Tannock IF, Rotin D. Acid pH in tumors and its potential for Therapeutic exploitation. JBR-BTR.49,4373–4384 (1989).CAS, Google Scholar
82 Striolo A. The mechanism of water diffusion in narrow carbon nanotubes. Nano. Lett.6,633–639 (2006).Crossref, Medline, CAS, Google Scholar
83 Jankovski A, Raftopoulos C, Vaz G et al. Intra-operative MRI at 3T: short report. JBR-BTR. 90,249–251 (2007).Google Scholar
84 McDermott R, Lee SK, ten Haken B, Trabesinger AH, Pines A, Clarke J. Microtesla MRI with a superconducting quantum interference device. Proc. Natl Acad. Sci. USA101,7857–7861 (2004).Crossref, Medline, CAS, Google Scholar
85 Mansfield P. Snapshot magnetic resonance imaging (nobel lecture). Angew. Chem. Int. Ed. Engl.43,5456–5464 (2004).Crossref, Medline, CAS, Google Scholar
86 Mackeyev Y, Hartman KB, Ananta JS, Lee AV, Wilson LJ. Catalytic synthesis of amino acid and peptide derivatized gadonanotubes. J. Am. Chem. Soc.131,8342 (2009).Crossref, Medline, CAS, Google Scholar
87 Langer M, Kratz F, Rothen-Rutishauser B, Wunderli-Allenspach H, Beck-Sickinger AG. Novel peptide conjugates for tumor-specific chemotherapy. J. Med. Chem.44,1341–1348 (2001).Crossref, Medline, CAS, Google Scholar
88 Hassan AA, Chan BT, Tran LA et al. Serine-derivatized gadonanotubes as magnetic nanoprobes for intracellular labeling. Contrast Media Mol. Imaging DOI: 10.1002/cmmi.293 (2009) (Epub ahead of print).▪▪ Establishes gadonanotubes as a new intracellular cell-labeling technology.Google Scholar
89 Grobner T. Gadolinium – a specific trigger for the development of nephrogenic fibrosing dermopathy and nephrogenic systemic fibrosis? Nephrol. Dial. Transplant.21,1104–1108 (2006).Crossref, Medline, CAS, Google Scholar
90 Grobner T, Prischl FC. Gadolinium and nephrogenic systemic fibrosis. Kidney Int.72,260–264 (2007).Crossref, Medline, CAS, Google Scholar
91 High WA, Ayers RA, Chandler J, Zito G, Cowper SE. Gadolinium is detectable within the tissue of patients with nephrogenic systemic fibrosis. J. Am. Acad. Dermatol.56,21–26 (2007).Crossref, Medline, Google Scholar
92 Thakral C, Abraham JL. Nephrogenic systemic fibrosis: histology and gadolinium detection. Radiol. Clin. North Am.47,841–846 (2009).Crossref, Medline, Google Scholar
93 Todd DJ, Kagan A, Chibnik LB, Kay J. Cutaneous changes of nephrogenic systemic fibrosis - Predictor of early mortality and association with gadolinium exposure. Arthritis Rheum.56,3433–3441 (2007).Crossref, Medline, Google Scholar
94 Winter TC, Freeny PC, Nghiem HV et al. MR-Imaging with IV-superparamagnetic iron-oxide – efficacy in the detection of focal hepatic-lesions. Am. J. Roentgenol.161,1191–1198 (1993).Crossref, Medline, Google Scholar
101 Latest IMV market report shows MRI procedure growth slowing to 3% per year. IMV Technologies. Press Release (2008). www.imvinfo.com/index.asp?Sec=abt&Sub=prs&Pag=dis&ItemId=200242Google Scholar

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Published online 17 March 2010

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Financial & competing interests disclosure

This work was supported by the Nanoscale Science and Engineering Initiative of the National Science Foundation (NSF Award Number EEC-00647452), The Robert A. Welch Foundation (Grant C-0627), the Houston Alliance for NanoHealth Award (6130G) and the Department of the Army (Grant W8XWH-07-02-0101). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

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