18F-FDG PET/CT findings in a possible MELAS syndrome: A case study

Document Type: Case Report


1 Research Center for Nuclear Medicine, Tehran University of Medical Sciences, Tehran, Iran

2 Association of Nuclear Medicine and Molecular Imaging (ANMMI), Universal Scientific Education and Research Network (USERN), Tehran, Iran


Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a rare congenital disorder of mitochondrial DNA, presenting a wide range of clinical symptoms comprising headaches, seizures, aphasia, hearing loss, visual defects, and hemiparesis. Herein we report a case of a previously asymptomatic 40-year-old male who presented with recurrent headache, seizures, Wernicke’s aphasia, and impaired visual acuity. Investigations included CT, MRI, MR venography, MR spectroscopy, and PET/CT with 18F-fluorodeoxyglucose (18F-FDG-PET) of the brain. PET imaging showed diffuse increased 18F-FDG uptake in the right hemisphere and left temporal lobe; additionally, decreased 18F-FDG uptake was observed in the left frontoparietal lobe. The patient underwent treatment by levetiracetam, co-enzyme Q10, riboflavin, L-carnitine, and lacosamide, followed by improvement of his clinical signs and symptoms indicative of partial response to the therapy.


Main Subjects

  1. Pavlakis SG, Phillips PC, DiMauro S, De Vivo DC, Rowland LP. Mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes: a distinctive clinical syndrome. Ann Neurol. 1984 Oct;16(4):481-8.
  2. Goto Y, Nonaka I, Horai S. A mutation in the tRNA(Leu)(UUR) gene associated with the MELAS subgroup of mitochondrial encephalomyopathies. Nature. 1990 Dec 13;348(6302):651-3.
  3. Wang YX, Le WD. Progress in diagnosing mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes. Chin Med J (Engl). 2015 Jul 5;128(13):1820-5.
  4. Ramanathan RS, Malhotra K, Scott T. Teaching NeuroImages: diffuse cerebral neurosarcoidosis mimicking gliomatosis cerebri. Neurology. 2013 Aug 13;81(7):e46.
  5. Malhotra K, Liebeskind DS. Imaging of MELAS. Curr Pain Headache Rep. 2016 Sep;20(9):54.
  6. Ikawa M, Okazawa H, Arakawa K, Kudo T, Kimura H, Fujibayashi Y, Kuriyama M, Yoneda M. PET imaging of redox and energy states in stroke-like episodes of MELAS. Mitochondrion. 2009 Apr;9(2):144-8.
  7. Yoneda M, Ikawa M, Arakawa K, Kudo T, Kimura H, Fujibayashi Y, Okazawa H. In vivo functional brain imaging and a therapeutic trial of L-arginine in MELAS patients. Biochim Biophys Acta. 2012 May;1820(5):615-8.
  8. Yoshii Y, Yoneda M, Ikawa M, Furukawa T, Kiyono Y, Mori T, Yoshii H, Oyama N, Okazawa H, Saga T, Fujibayashi Y. Radiolabeled Cu-ATSM as a novel indicator of overreduced intracellular state due to mitochondrial dysfunction: studies with mitochondrial DNA-less ρ0 cells and cybrids carrying MELAS mitochondrial DNA mutation. Nucl Med Biol. 2012 Feb;39(2):177-85.
  9. Rodan LH, Poublanc J, Fisher JA, Sobczyk O, Wong T, Hlasny E, Mikulis D, Tein I. Cerebral hyperperfusion and decreased cerebrovascular reactivity correlate with neurologic disease severity in MELAS. Mitochondrion. 2015 May;22:66-74.
  10. Molnár MJ, Valikovics A, Molnár S, Trón L, Diószeghy P, Mechler F, Gulyás B. Cerebral blood flow and glucose metabolism in mitochondrial disorders. Neurology. 2000 Aug 22;55(4):544-8.