An 1-month-old baby without any perinatal insult presented with left focal seizures since day 12 of life. He had multiple seizures daily. He had a seizure just before undergoing magnetic resonance imaging (MRI), which was suggestive of post-ictal oedema versus hemimegalencephaly [Figure 1a-d] with arterial spin labelling (ASL) perfusion showing hyperperfusion in the right cerebral hemisphere [Figure 1i and j]. His repeat MRI at 3 months [Figure 1e-h] showed hemimegalncephaly with ASL showing hypoperfusion in the right cerebral hemisphere [Figure 1k and l]. He did not have a seizure prior to MRI this time. ASL changes helped in identification of epileptic focus.
Figure 1.
T2W, T1W, DWI axial images at 1 month (a-d) and 3 months of ages (e-h) reveal mild enlargement of the right cerebral hemisphere with slight hypertrophy and mild hypermyelination of the centrum semiovale (*) and blurring of gray-white matter junction (arrow) compared to the left cerebral hemisphere. ASL perfusion study shows peri-ictal hyperperfusion in the entire right cerebral hemisphere at 1 month of age (i and j) and inter-ictal hypoperfusion at 3 months of age (k and l)
Ictal and interictal single photon emission-computed tomography (SPECT) and PET (positron imaging tomography) are often used to detect metabolic changes related to epileptic activity. ASL can be used as an additional functional marker of cerebral perfusion with minimal additional effort. ASL is an MRI technique used to assess cerebral blood flow (CBF) noninvasively by magnetically labelled blood as an endogenous contrast agent.[1,2] The CBF is reduced in the chronic interictal period as the epileptogenic region is less functional and active compared with the normal brain tissue.[3,4] The CBF is typically increased in the acute peri-ictal period due to pathologic neuronal activity. Hypoperfusion on ASL images closely matches the patterns of hypometabolism on fluorine 18 fluorodeoxyglucose (FDG) PET images due to the close coupling of perfusion and metabolism in the brain.[1,5] Hence, ASL perfusion study can be useful as an additional and complementary tool and probably a noninvasive surrogate marker to FDG PET.
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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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REFERENCES
- 1.Kim BS, Lee ST, Yun TJ, Lee SK, Paeng JC, Jun J, et al. Capability of arterial spin labeling MR imaging in localizing seizure focus in clinical seizure activity. Eur J Radiol. 2016;85:1295–303. doi: 10.1016/j.ejrad.2016.04.015. [DOI] [PubMed] [Google Scholar]
- 2.Nagesh C, Kumar S, Menon R, Thomas B, Radhakrishnan A, Kesavadas C. The imaging of localization related symptomatic epilepsies: The value of arterial spin labelling based magnetic resonance perfusion. Korean J Radiol. 2018;19:965–77. doi: 10.3348/kjr.2018.19.5.965. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Nguyen D, Kapina V, Seeck M, Viallon M, Fedespiel A, Lovblad KO. Ictal hyperperfusion demonstrated by arterial spin-labeling MRI in status epilepticus. J Neuroradiol. 2010;37:250–1. doi: 10.1016/j.neurad.2009.12.003. [DOI] [PubMed] [Google Scholar]
- 4.Pendse N, Wissmeyer M, Altrichter S, Thomas B, Radhakrishnan A, Kesavadas C. Interictal arterial spin-labeling MRI perfusion in intractable epilepsy. J Neuroradiol. 2010;37:60–3. doi: 10.1016/j.neurad.2009.05.006. [DOI] [PubMed] [Google Scholar]
- 5.Blauwblomme T, Boddaert N, Chémaly N, Chiron C, Pages M, Varlet P, et al. Arterial spin labeling MRI: A step forward in non-invasive delineation of focal cortical dysplasia in children. Epilepsy Res. 2014;108:1932–9. doi: 10.1016/j.eplepsyres.2014.09.029. [DOI] [PubMed] [Google Scholar]