CC BY 4.0 · Indian Journal of Neurosurgery 2023; 12(02): 147-154
DOI: 10.1055/s-0042-1743398
Original Article

Effect of Whole-body [18F]Fluoro-2-deoxy-2-d-glucose Positron Emission Tomography in Patients with Suspected Brain Metastasis

1   Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Neetu Soni
2   Department of Neuroradiology, University of Iowa Health and Clinic, Iowa, Iowa, United States
Aftab Hasan Nazar
1   Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Anant Mehrotra
3   Department of Neurosurgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Prabhakar Mishra
4   Department of Biostatistics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Sanjay Gambhir
1   Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
› Author Affiliations


Background and Purpose [18F]Fluoro-2-deoxy-2-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) has a promising role in the workup and management of carcinoma of unknown primary (CUP). We have evaluated the effect of whole-body FDG PET/CT in assessing the patients presented with suspected brain metastasis (CUP-BM) on brain magnetic resonance imaging (MRI) or computed tomography (CT).

Materials and Methods This retrospective study included FDG PET/CT of 50 patients (24 males, mean: 58 ± 12.2 years old) with a CUP-BM diagnosis based on MRI and CT imaging. The final diagnosis of primary brain neoplasm (BP) or brain metastases (BM) was based on FDG PET/CT findings and/or histopathology (HPE).

Results On FDG PET/CT, 52% (26/50) of patients did not have any systemic lesion apart from a brain lesion. Out of these, 50% (13/26) had HPE confirmation of primary brain neoplasm (BP). FDG PET/CT identified multiple systemic lesions apart from brain lesions in the remaining 48% (24/50) of patients. They were categorized as the brain metastases (BM) group. The primary lesions were located in the lungs (n = 20), kidneys (n = 1), prostate (n = 1), esophagus (n = 1), and tongue (n = 1).

Conclusion FDG PET/CT could suggest a diagnosis of BM based on the presence of systemic lesions. It also provides an easily accessible peripheral site for biopsy and systemic disease burden in a single scan. FDG PET/CT's up-front use in suspected CUP-BM on CT and/or MRI could differentiate the BM from BP in most cases and avoid brain biopsy in the BM group.

Availability of Data and Material (Data Transparency)

Data are partially available after a request from the corresponding author. It contains patient no. identification.

Ethical Approval Statement

It was a retrospective study on anonymized data, and all investigations and procedures were done as part of the standard of care. The ethical committee's permission was not required.

Authors' Contribution

M.O. and S.G. contributed to the concept and design of the study. A.H.N., P.M., and A.M. did data collection, data, and statistical analysis. M.O., N.S. wrote the first draft. A.H.N., N.S., A.M., did manuscript preparation and figure preparation. M.O., N.S. and S.G. finalized manuscript.

Publication History

Article published online:
16 May 2022

© 2022. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (

Thieme Medical and Scientific Publishers Pvt. Ltd.
A-12, 2nd Floor, Sector 2, Noida-201301 UP, India

  • References

  • 1 Burglin SA, Hess S, Høilund-Carlsen PF, Gerke O. 18F-FDG PET/CT for detection of the primary tumor in adults with extracervical metastases from cancer of unknown primary: a systematic review and meta-analysis. Medicine (Baltimore) 2017; 96 (16) e6713
  • 2 Haas I, Hoffmann TK, Engers R, Ganzer U. Diagnostic strategies in cervical carcinoma of an unknown primary (CUP). Eur Arch Otorhinolaryngol 2002; 259 (06) 325-333
  • 3 American Cancer Society | Information and Resources about for Cancer: Breast, Colon, Lung, Prostate, Skin. Accessed November 23, 2020. Available at:
  • 4 NORDCAN. Accessed November 23, 2020. Available at:
  • 5 Le Chevalier T, Cvitkovic E, Caille P. et al. Early metastatic cancer of unknown primary origin at presentation. A clinical study of 302 consecutive autopsied patients. Arch Intern Med 1988; 148 (09) 2035-2039
  • 6 Hemminki K, Bevier M, Hemminki A, Sundquist J. Survival in cancer of unknown primary site: population-based analysis by site and histology. Ann Oncol 2012; 23 (07) 1854-1863
  • 7 Soffietti R, Abacioglu U, Baumert B. et al. Diagnosis and treatment of brain metastases from solid tumors: guidelines from the European Association of Neuro-Oncology (EANO). Neuro-oncol 2017; 19 (02) 162-174
  • 8 Sperduto PW, Berkey B, Gaspar LE, Mehta M, Curran W. A new prognostic index and comparison to three other indices for patients with brain metastases: an analysis of 1,960 patients in the RTOG database. Int J Radiat Oncol Biol Phys 2008; 70 (02) 510-514
  • 9 Gould MK, Kuschner WG, Rydzak CE. et al. Test performance of positron emission tomography and computed tomography for mediastinal staging in patients with non-small-cell lung cancer: a meta-analysis. Ann Intern Med 2003; 139 (11) 879-892
  • 10 Reinhardt MJ, Joe AY, Jaeger U. et al. Diagnostic performance of whole body dual modality 18F-FDG PET/CT imaging for N- and M-staging of malignant melanoma: experience with 250 consecutive patients. J Clin Oncol 2006; 24 (07) 1178-1187
  • 11 Fischer B, Lassen U, Mortensen J. et al. Preoperative staging of lung cancer with combined PET-CT. N Engl J Med 2009; 361 (01) 32-39
  • 12 Moller AKH, Loft A, Berthelsen AK. et al. 18F-FDG PET/CT as a diagnostic tool in patients with extracervical carcinoma of unknown primary site: a literature review. Oncologist 2011; 16 (04) 445-451
  • 13 Kwee TC, Kwee RM. Combined FDG-PET/CT for the detection of unknown primary tumors: systematic review and meta-analysis. Eur Radiol 2009; 19 (03) 731-744
  • 14 Dong MJ, Zhao K, Lin XT, Zhao J, Ruan LX, Liu ZF. Role of fluorodeoxyglucose-PET versus fluorodeoxyglucose-PET/computed tomography in detection of unknown primary tumor: a meta-analysis of the literature. Nucl Med Commun 2008; 29 (09) 791-802
  • 15 Klee B, Law I, Højgaard L, Kosteljanetz M. Detection of unknown primary tumours in patients with cerebral metastases using whole-body 18F-flouorodeoxyglucose positron emission tomography. Eur J Neurol 2002; 9 (06) 657-662
  • 16 Jeong H-J, Chung J-K, Kim YK. et al. Usefulness of whole-body (18)F-FDG PET in patients with suspected metastatic brain tumors. J Nucl Med 2002; 43 (11) 1432-1437
  • 17 Koç ZP, Kara PÖ, Dağtekin A. Detection of unknown primary tumor in patients presented with brain metastasis by F-18 fluorodeoxyglucose positron emission tomography/computed tomography. CNS Oncol 2018; 7 (02) CNS12
  • 18 Wolpert F, Weller M, Berghoff AS. et al. Diagnostic value of 18F-fluordesoxyglucose positron emission tomography for patients with brain metastasis from unknown primary site. Eur J Cancer 2018; 96 (96) 64-72
  • 19 Delbeke D, Coleman RE, Guiberteau MJ. et al. Procedure guideline for tumor imaging with 18F-FDG PET/CT 1.0. J Nucl Med 2006; 47 (05) 885-895
  • 20 Achrol AS, Rennert RC, Anders C. et al. Brain metastases. Nat Rev Dis Primers 2019; 5 (01) 5
  • 21 Ostrom QT, Wright CH, Barnholtz-Sloan JS. Brain metastases: epidemiology. Handb Clin Neurol 2018; 149: 27-42
  • 22 Mavrakis AN, Halpern EF, Barker II FG, Gonzalez RG, Henson JW. Diagnostic evaluation of patients with a brain mass as the presenting manifestation of cancer. Neurology 2005; 65 (06) 908-911
  • 23 Meric K, Killeen RP, Abi-Ghanem AS. et al. The use of 18F-FDG PET ratios in the differential diagnosis of common malignant brain tumors. Clin Imaging 2015; 39 (06) 970-974