Indian Journal of Nuclear Medicine
Home | About IJNM | Search | Current Issue | Past Issues | Instructions | Ahead of Print | Online submissionLogin 
Indian Journal of Nuclear Medicine
  Editorial Board | Subscribe | Advertise | Contact
Users Online: 423 Print this page  Email this page Small font size Default font size Increase font size


 
 Table of Contents     
CASE REPORT
Year : 2013  |  Volume : 28  |  Issue : 2  |  Page : 93-95  

Hemimegalencephaly: A rare cause of hemihypoperfusion on 99m technetium-ethyl cysteinate dimer brain perfusion single-photon emission computed tomography


Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India

Date of Web Publication16-Sep-2013

Correspondence Address:
Nishikant A Damle
Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi - 110 029
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-3919.118257

Rights and Permissions
   Abstract 

Hemimegalencephaly is a rare congenital neuronal migration disorder that can presents with the equally rare finding of hemihypoperfusion on brain perfusion single-photon emission computed tomography (SPECT). It is an extremely rare cause of intractable epilepsy. Technetium-99m ethyl cysteinate dimer (ECD) brain perfusion SPECT is useful in excluding other foci of hypoperfusion in the contralateral since hemispherectomy has been suggested to be the treatment of choice. Furthermore, hemimegalencephaly may present with hyper as well as hypoperfusion on ECD SPECT. We present the case of an 11-year-old male child with intractable seizures who showed hemihypoperfusion in the hemimegalecephalic hemisphere.

Keywords: 99m technetium-ethyl cysteinate dimer brain single-photon emission computed tomography, hemihypoperfusion, hemimegalencephaly


How to cite this article:
Damle NA, Singhal A, Mukherjee A, Sahoo MK, Tripathi M, Bal C. Hemimegalencephaly: A rare cause of hemihypoperfusion on 99m technetium-ethyl cysteinate dimer brain perfusion single-photon emission computed tomography. Indian J Nucl Med 2013;28:93-5

How to cite this URL:
Damle NA, Singhal A, Mukherjee A, Sahoo MK, Tripathi M, Bal C. Hemimegalencephaly: A rare cause of hemihypoperfusion on 99m technetium-ethyl cysteinate dimer brain perfusion single-photon emission computed tomography. Indian J Nucl Med [serial online] 2013 [cited 2019 Dec 7];28:93-5. Available from: http://www.ijnm.in/text.asp?2013/28/2/93/118257


   Introduction Top


Hemimegalencephaly is a rare congenital neuronal migration disorder characterized by unilateral hypertrophy of a cerebral hemisphere and ipsilateral ventriculomegaly. [1],[2] It can be an isolated abnormality, or it can be associated with neurocutaneous syndromes. [1] Clinical manifestations include intractable motor seizures, impaired psychomotor development, hemiparesis, and hemianopsia. [1] Patients having hemimegalencephaly usually have a very poor prognosis. These patients require early surgical interventions to prevent progression to intractable epilepsy. [3] Hemispherectomy is the treatment of choice. [1] The definition of the dysfunctional areas of dysplastic cortex may affect surgical management of these anomalies. [4] Evaluation of regional cerebral blood flow using technetium-99m ethyl cysteinate dimer (Tc-99m ECD) single-photon emission computed tomography (SPECT) provides useful information in the patient of hemimegalencephaly [5],[6] because it clearly delineates the border of the dysplastic cortex by showing altered blood flow to the dysfunctional areas. [4]


   Case Report Top


An 11-year-old male child was referred to a tertiary care hospital with history of gradually increasing seizures frequency since infancy. The child had delayed milestones and right hemiparesis. Seizures were mainly right sided, complex partial in nature and refractory to medical treatment over the past decade. The child was born out of non-consanguineous marriage, at term with a normal vaginal delivery. There was no family history of neurologic diseases. Non-contrast computed tomography (CT) of head showed diffuse enlargement of left cerebral hemisphere with midline shift towards right while the right cerebral hemisphere was normal [Figure 1]a. T2W magnetic resonance imaging (MRI) images showed diffuse gyral thickening involving the left cerebral cortex causing midline shift and scalloping of inner table of left calvarium [Figure 1]b.White matter in both cerebral hemispheres show normal myelination. Linear hyperintensities involving the subcortical U fibers of left fronto-parietal region were seen on the fluid attenuation inversion recovery image [Figure 1]c.

Post-gadolinium T1W image in axial plane showed no abnormal enhancement [Figure 1]d. Tc-99m ECD brain perfusion SPECT revealed diffusely decreased tracer uptake in the left cerebral hemisphere, with normal uptake in the right hemisphere suggestive of left cerebral hemihypoperfusion [Figure 2]a-c.
Figure 1: Non-contrast computed tomography of head (a) Axial shows diffuse enlargement of left cerebral hemisphere (*) with midline shift towards right while the right hemisphere is normal. Non-contrast magnetic resonance imaging T2W (b) Images (axial) show diffuse gyral thickening (thin arrow) in the left cerebrum causing midline shift and scalloping of inner table (arrow head) of left calvarium. White matter in both cerebral hemispheres show normal myelination. Linear hyperintensities involving the subcortical U fibers of left fronto-parietal region seen on fluid attenuation inversion recovery image (c) Post-gadolinium T1W image in axial plane (d) shows no abnormal enhancement

Click here to view
Figure 2: 99m technetium-ethyl cysteinate dimer brain perfusion single-photon emission computed tomography transaxial, coronal and sagittal images reveal diffusely decreased tracer uptake in the left cerebral hemisphere (arrow), with normal uptake in the right hemisphere. Findings are suggestive of left cerebral hemihypoperfusion

Click here to view



   Discussion Top


Tc-99m ECD is a perfusion agent similar to Tc-99m hexamethylpropyleneamine oxime (HMPAO). Regional differences in perfusion within the affected hemisphere with relative interictal hypoperfusion and ictal hyperperfusion of the seizure focus in a neonate with hemimegalencephaly has been reported on Tc-99m HMPAO brain SPECT imaging. [7] Ictal SPECT using Tc-99m HMPAO is also useful in demonstrating the site of epileptogenesis and its spread. [2] Sometimes it has been found that brain SPECT shows increased radiotracer uptake in the pathological hemisphere in the early part of life, which gets reversed in the later stage with decreased radiotracer uptake in the pathological hemisphere. These serial changes of radiotracer uptake on SPECT probably reflect either changes in epileptic activity or maturational changes in cerebral perfusion in hemimegalencephaly. [8] Brain SPECT helps in excluding seizure foci or other perfusion abnormalities in the contralateral side before surgery. [1] Considering recent recommendations for hemispherectomy in these patients, Tc-99m ECD/HMPAO SPECT scan should be used to complement electroencephalogram (EEG) as a method to define the extent of abnormality, which may be more relevant to long-term prognosis than EEG alone. [9] Also, while interpreting a brain SPECT, hemimegalencephaly must be considered as a differential in hemihypoperfusion, for which CT/MRI correlation should be sought before reporting. The other differentials for hemispheric hypoperfusion are Rasmussen's encephalitis, [10] Sturge  Weber syndrome More Details, [11] Aspergers syndrome, [12] exanthema subitum [13] and gliomatosis cerebri, [14] which can even be mistaken for hemimegalencephaly.

 
   References Top

1.Bar-Sever Z, Connolly LP, Barnes PD, Treves ST. Brain SPECT evaluation of cerebral perfusion in hemimegalencephaly. Clin Nucl Med 1997;22:250-2.  Back to cited text no. 1
[PUBMED]    
2.Tanaka Y, Hamano S, Nara T, Nakanishi Y. A case of hemimegalencephaly: Ictal EEG and SPECT. No To Hattatsu 1994;26:528.  Back to cited text no. 2
[PUBMED]    
3.Uematsu M, Haginoya K, Togashi N, Hino-Fukuyo N, Nakayama T, Kikuchi A, et al. Unique discrepancy between cerebral blood flow and glucose metabolism in hemimegalencephaly. Epilepsy Res 2010;92:201-8.  Back to cited text no. 3
    
4.Tutuncuoglu S, Tekgul H, Duman Y, Kayalioglu M. 99m Tc HMPAO-SPECT in patients with neuronal migration anomalies. Turkish Journal of Nuclear Medicine 1996;5:165-9.  Back to cited text no. 4
    
5.Podreka I, Suess E, Goldenberg G, Steiner M, Brücke T, Müller C, et al. Initial experience with technetium-99m HM-PAO brain SPECT. J Nucl Med 1987;28:1657-66.  Back to cited text no. 5
    
6.Ozkiriş A, Evereklioglu C, Kula M, Somdaş M, Erkiliç K, Coşkun A. Tc-99m HMPAO brain SPECT in linear nevus sebaceous syndrome. Ann Nucl Med 2003;17:703-6.  Back to cited text no. 6
    
7.Alfonso I, Harvey S, Acuña A, Velez E, Papazian O, Litt R, et al. Interictal and ictal SPECT in a neonate with hemimegalencephaly. Clin Nucl Med 1997;22:323-4.  Back to cited text no. 7
    
8.Tagawa T, Otani K, Futagi Y, Wakayama A, Morimoto K, Morita Y. Serial IMP-SPECT and EEG studies in an infant with hemimegalencephaly. Brain Dev 1994;16:475-9.  Back to cited text no. 8
[PUBMED]    
9.Konkol RJ, Maister BH, Wells RG, Sty JR. Hemimegalencephaly: Clinical, EEG, neuroimaging, and IMP-SPECT correlation. Pediatr Neurol 1990;6:414-8.  Back to cited text no. 9
[PUBMED]    
10.Tessonnier L, Thomas P, Benisvy D, Chanalet S, Chaborel JP, Bussière F, et al. Perfusion SPECT findings in a suspected case of Rasmussen encephalitis. J Neuroimaging 2009;19:378-80.  Back to cited text no. 10
    
11.Aylett SE, Neville BG, Cross JH, Boyd S, Chong WK, Kirkham FJ. Sturge-Weber syndrome: Cerebral haemodynamics during seizure activity. Dev Med Child Neurol 1999;41:480-5.  Back to cited text no. 11
[PUBMED]    
12.Yang WH, Jing J, Xiu LJ, Cheng MH, Wang X, Bao P, et al. Regional cerebral blood flow in children with autism spectrum disorders: A quantitative 99mTc-ECD brain SPECT study with statistical parametric mapping evaluation. Chin Med J (Engl) 2011;124:1362-6.  Back to cited text no. 12
[PUBMED]    
13.Ohta H, Watanabe Y, Sumimoto S, Kojima N, Ishigaki T, Todo G, et al. Hypoperfusion of right hemisphere on brain SPECT in a patient with exanthem subitum and left hemiparesis. Ann Nucl Med 2000;14:223-5.  Back to cited text no. 13
[PUBMED]    
14.Maton B, Resnick T, Jayakar P, Morrison G, Duchowny M. Epilepsy surgery in children with gliomatosis cerebri. Epilepsia 2007;48:1485-90.  Back to cited text no. 14
[PUBMED]    


    Figures

  [Figure 1], [Figure 2]



 

Top
  
 
  Search
 
  
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    Abstract
   Introduction
   Case Report
   Discussion
    References
    Article Figures

 Article Access Statistics
    Viewed968    
    Printed37    
    Emailed0    
    PDF Downloaded59    
    Comments [Add]    

Recommend this journal