Downloaded from http://journals.lww.com/nuclearmed by BhDMf5ePHKbH4TTImqenVFao8o3NFiILDnihHIM+SqFSERP0vG6YWaqtOUAJAQ7yUW5Jn/JW4qc= on 10/23/2020 PET/CT in Evaluation of Low Backache Due to Sacral Nerve Root Involvement Inflammatory and Malignant Involvement Divya Yadav, MD,* Meivel Angamuthu, MD,* T. Kishan Subudhi, MBBS,* Chandan J. Das, MD,† and Rakesh Kumar, MD* Abstract: Low back pain with radiation to lower limbs is due to nerve root impingement or involvement in most cases. 18 F-FDG PET/CT has shown sacral nerve root involvement in several peripheral nerve pathologies, including neurolymphomatosis, peripheral nerve sheath tumor, and plexopathies. We present 2 cases of a low back pain with ulcerative colitis and metastatic neu- roendocrine tumor who underwent 18 F-FDG PET/CT and 68 Ga-DOTANOC PET/CT, respectively. PET/CT can be used as an adjunct tool to evaluate sacral nerve root involvement to look for malignant or inflammatory nerve involvement. Key Words: PET/CT, ulcerative colitis, neurolymphomatosis, plexopathies, nerve root involvement (Clin Nucl Med 2020;45: e299–e300) REFERENCES 1. Guo H, Mosci C, Iagaru A, et al. Demonstration of peripheral nerve root in- volvement by non-Hodgkin's lymphoma on 18 F-FDG PET/CT. Eur J Nucl Med Mol Imaging. 2012;39:729–730. 2. Wang Y , Wang J, Jiang C, et al. Secondary neurolymphomatosis of spinal nerve roots detected by 18 F-FDG PET/CT: a case report and differential di- agnosis of the case. Hell J Nucl Med. 2015;18:261–263. 3. Sideras PA, Matthews J, Sakib SM, et al. Neurolymphomatosis of the periph- eral nervous system: a case report and review of the literature. Clin Imaging. 2016;40:1253–1256. 4. Roy S, Parida G, Tripathy S, et al. Active leprosy neuritis detected on FDG PET/CT. Clin Nucl Med. 2018;43:132–133. 5. Figueroa JJ , Loftus EV Jr, Harmsen WS, et al. Peripheral neuropathy incidence in inflammatory bowel disease: a population-based study. Neurology . 2013;80: 1693–1697. 6. Cardin A, Patel M, Ma D, et al. Celiac disease on FDG PET/CT. Clin Nucl Med. 2019;44:e526–e528. 7. Crush AB, Howe BM, Spinner RJ, et al. Malignant involvement of the peripheral nervous system in patients with cancer: multimodality imaging and pathologic correlation – 1. Radiographics. 2014;34:1987–2007. 8. Liebig C, Aala G, Wilks JA, et al. Perineural invasion in cancer: a review of the literature. Cancer . 2009;115:3379–3391. 9. Metser U, Lerman H, Blank A, et al. Malignant involvement of the spine: as- sessment by 18 F-FDG PET/CT. J Nucl Med. 2004;45:279–284. 10. Crush AB, Howe BM, Spinner RJ, et al. Malignant involvement of the pe- ripheral nervous system in patients with cancer: multimodality imaging and pathologic correlation. Radiographics. 2014;34:1987–2007. Received for publication November 14, 2019; revision accepted February 16, 2020. From the Departments of *Nuclear Medicine, and †Radiology, All India Institute of Medical Science, New Delhi, India. Conflicts of interest and sources of funding: none declared. Correspondence to: Rakesh Kumar, MD, Diagnostic Nuclear Medicine Division, Department of Nuclear Medicine, All India Institute of Medical Science, Rajkumari Amrit Kaur O.P.D. New Delhi 110029, India. E-mail: rkphulia@yahoo.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/20/4506–e299 DOI: 10.1097/RLU.0000000000003021 FIGURE 1. A 29-year-old man with a known case of ulcerative colitis for 4 years presented with pain in lower back with radiation to bilateral lower limbs for 5 months. MIP image (A) of 18 F-FDG PET/CT scan shows increased radiotracer uptake along bilateral sacral nerve roots (marked with black arrows). Transaxial fused PET/CT and CT images (B and C) shows increased FDG uptake in bilateral sacral foramina, which correlates with thickened sacral nerve roots on MRI scan (D, marked with white arrows). Coronal fused PET/CT and CT images (E and F) illustrate increased FDG uptake along the sacral nerve roots in sacral canal, which correlates with the sacral nerve roots in sacral canal on MRI scan (G, marked with white arrows). There were no other lesions to suggest any malignant pathology. 18 F-FDG PET/CT has shown sacral nerve root involvement in several peripheral nerve pathologies, including neurolymphomatosis, peripheral nerve sheath tumor, and plexopathies. 1–4 The bilateral sacral nerve root involvement was considered as inflammatory involvement, and it is a commonly reported neurologic complication of inflammatory bowel disease. 5,6 INTERESTING IMAGE Clinical Nuclear Medicine • Volume 45, Number 6, June 2020 www.nuclearmed.com e299 Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.