Peripheral Nerves, Tumors, and Hybrid PET-MRI

INTERESTING IMAGE

Peripheral Nerves, Tumors, and Hybrid PET-MRI Maria Isabel Vargas, MD,* Valentina Garibotto, MD,Þ Magalie Viallon, MD, PhD,þ Renaud Guignard, MD,Þ Victor Cuvinciuc, MD,* Karl Lovblad, MD,* and Osman Ratib, MDÞ

Abstract: The study of peripheral nerves (PN) is a challenge because of the orientation, size, and also because of the fact that these pathologies are not well known. The diagnosis of PN damage was based exclusively on clinical examination and electrophysiologic testing until few years ago. MRI is the examination of choice for studying peripheral nerves; recently, magnetic resonance neurography has been added as a part of clinical routine. However, the analysis of PN after surgical treatment remains difficult. This clinical case of a sarcoma of the right brachial plexus illustrates how hybrid PET-MRI in postsurgical evaluation will clearly improve the exact delimitation of residual metabolically active tumor after surgery. Key Words: PET, MRI, peripheral nerves, tumors, 3D STIR (Clin Nucl Med 2013;38: e40Ye42)

Received for publication November 3, 2011; revision accepted January 22, 2012. From the Departments of *Neuroradiology; †Nuclear Medicine; and ‡Radiology, Geneva University Hospital and University of Geneva, Geneva, Switzerland. Conflicts of interest and sources of funding: none declared. Reprints: Maria Isabel Vargas, MD, Department of Neuroradiology, DISIM, Geneva University Hospital, 4 Gabrielle-Perret-Gentil, 1211 Geneva 14, Switzerland. E-mail: [email protected]. Copyright * 2012 by Lippincott Williams & Wilkins ISSN: 0363-9762/13/3801Y0e40

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REFERENCES 1. Vargas MI, Viallon M, Nguyen D, et al. New approaches in imaging of the brachial plexus. Eur J Radiol. 2010;74:403Y410. 2. Viallon M, Vargas MI, Jlassi H, et al. High-resolution and functional magnetic resonance imaging of the brachial plexus using an isotropic 3D T2 STIR (Short Term Inversion Recovery) SPACE sequence and diffusion tensor imaging. Eur Radiol. 2008;18:1018Y1023. 3. Vargas MI, Viallon M, Nguyen D, et al. Diffusion tensor imaging (DTI) and tractography of the brachial plexus: feasibility and initial experience in neoplastic conditions. Neuroradiology. 2010;52:237Y245. 4. Yoshikawa T, Hayashi N, Yamamoto S, et al. Brachial plexus injury: clinical manifestations, conventional imaging findings, and the latest imaging techniques. Radiographics. 2006;26:S133YS143. 5. Eary JF, Link JM, Muzi M, et al. Multiagent PET for risk characterization in sarcoma. J Nucl Med. 2011;52:541Y546. 6. Ratib O, Beyer T. Whole-body hybrid PET/MRI: ready for clinical use? Eur J Nucl Med Mol Imaging. 2011;38:992Y995. 7. Bronstein Y, Tummala S, Rohren E. F-18 FDG PET/CT for detection of malignant involvement of peripheral nerves: case series and literature review. Clin Nucl Med. 2011;36:96Y100. 8. Lee NK, Lee BH, Hwang YJ, et al. Findings from CT, MRI, and PET/CT of a primary malignant melanoma arising in a spinal nerve root. Eur Spine J. 2010;19:174Y178.

Clinical Nuclear Medicine

& Volume 38, Number 1, January 2013

Copyright © 2012 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.



Peripheral Nerves, Tumors, and Hybrid PET-MRI

FIGURE 1. Sarcoma of the right brachial plexus; 3 dimensional STIR SPACE (Sampling Perfection with Application optimized Contrasts using different flip angle Evolutions) coronal reconstruction1Y4 showing a voluminous and infiltrating mass with ill-delineated edges at level of right brachial plexus; note the extension of tumor to C6, C7, C8, and TH1 roots.

FIGURE 2. Sarcoma of the right brachial plexus after surgery; hybrid PET-MRI5,6: coronal PET, coronal STIR sequence, and coregistration of both techniques showing hypermetabolism at level of C7 (A) enlarged and irregular root on MRI (B), and exactly residual tumor metabolically active on coregistration (C, arrow). * 2012 Lippincott Williams & Wilkins

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FIGURE 3. Sarcoma of the right brachial plexus after surgery; coregistration of axial T2 with PET and coronal STIR,7,8 showing residual tumor at level of C7 root (arrow).

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* 2012 Lippincott Williams & Wilkins
