The Power Button Sign: A Newly Described Central Sulcal Pattern on Surface Rendering MR Images of Type 2 Focal Cortical Dysplasia

Published Online:https://doi.org/10.1148/radiol.14140773

The power button sign, which enriches the MR semiology of type 2 focal cortical dysplasia, may increase diagnostic confidence when other cardinal MR criteria are visible or, more important, when these are lacking or doubtful.

Purpose

To compare the occurrence of several central sulcus variants and to assess the reproducibility of a sulcal pattern named the power button sign (PBS) in patients with type 2 focal cortical dysplasia (FCD2) and healthy control subjects.

Materials and Methods

The local institutional review board approved the study, and written informed consent was waived for patients and was obtained from control subjects. Four readers reviewed three-dimensional (3D) T1-weighted magnetic resonance (MR) images in 37 patients (13 with negative MR imaging findings) with histologically proven FCD2 of the central region and 44 control subjects on the basis of a visual analysis of a 3D reconstruction of cortical folds. They searched for central sulcus variations (interruptions, side branches, and connections) and for a particular sulcal pattern, namely, the interposition of a precentral sulcal segment between the central sulcus and one of its hook-shaped anterior ascending branches (ie, PBS). Inter- and intraobserver reliability, specificity, and sensitivity were calculated.

Results

The central sulcus showed a greater number of side branches (P < .001) and was more frequently connected to the precentral sulcus (P < .001) in patients with FCD2 than in control subjects. The PBS was found in 23 (62%) of 37 total patients with FCD2, in six (46%) of 13 with negative MR imaging findings, and in only one control subject. Inter- and intraobserver rates were excellent (0.88 and 0.93, respectively) for the detection of PBS. FCD2 was located either in the depth of the ascending branch of the central sulcus (14 of 23, 61%) or in its immediate vicinity (nine of 23).

Conclusion

Given its excellent reproducibility and specificity, the PBS, when present, could become a useful qualitative diagnostic MR criterion of FCD2 in the central region.

© RSNA, 2014

References

  • 1. Chassoux F, Devaux B, Landré E, et al. Stereoelectroencephalography in focal cortical dysplasia: a 3D approach to delineating the dysplastic cortex. Brain 2000;123(Pt 8):1733–1751.
  • 2. Urbach H, Scheffler B, Heinrichsmeier T, et al. Focal cortical dysplasia of Taylor’s balloon cell type: a clinicopathological entity with characteristic neuroimaging and histopathological features, and favorable postsurgical outcome. Epilepsia 2002;43(1):33–40.
  • 3. Fauser S, Bast T, Altenmüller DM, et al. Factors influencing surgical outcome in patients with focal cortical dysplasia. J Neurol Neurosurg Psychiatry 2008;79(1):103–105.
  • 4. Lerner JT, Salamon N, Hauptman JS, et al. Assessment and surgical outcomes for mild type I and severe type II cortical dysplasia: a critical review and the UCLA experience. Epilepsia 2009;50(6):1310–1335.
  • 5. McGonigal A, Bartolomei F, Régis J, et al. Stereoelectroencephalography in presurgical assessment of MRI-negative epilepsy. Brain 2007;130(Pt 12):3169–3183.
  • 6. Kim DW, Lee SK, Chu K, et al. Predictors of surgical outcome and pathologic considerations in focal cortical dysplasia. Neurology 2009;72(3):211–216.
  • 7. Chassoux F, Rodrigo S, Semah F, et al. FDG-PET improves surgical outcome in negative MRI Taylor-type focal cortical dysplasias. Neurology 2010;75(24):2168–2175.
  • 8. Mellerio C, Labeyrie MA, Chassoux F, et al. Optimizing MR imaging detection of type 2 focal cortical dysplasia: best criteria for clinical practice. AJNR Am J Neuroradiol 2012;33(10):1932–1938.
  • 9. Mellerio C, Labeyrie MA, Chassoux F, et al. 3T MRI improves the detection of transmantle sign in type 2 focal cortical dysplasia. Epilepsia 2014;55(1):117–122.
  • 10. Barkovich AJ, Kuzniecky RI, Bollen AW, Grant PE. Focal transmantle dysplasia: a specific malformation of cortical development. Neurology 1997;49(4):1148–1152.
  • 11. Yagishita A, Arai N, Maehara T, Shimizu H, Tokumaru AM, Oda M. Focal cortical dysplasia: appearance on MR images. Radiology 1997;203(2):553–559.
  • 12. Raymond AA, Fish DR, Sisodiya SM, Alsanjari N, Stevens JM, Shorvon SD. Abnormalities of gyration, heterotopias, tuberous sclerosis, focal cortical dysplasia, microdysgenesis, dysembryoplastic neuroepithelial tumour and dysgenesis of the archicortex in epilepsy: clinical, EEG and neuroimaging features in 100 adult patients. Brain 1995;118(Pt 3):629–660.
  • 13. Krsek P, Maton B, Korman B, et al. Different features of histopathological subtypes of pediatric focal cortical dysplasia. Ann Neurol 2008;63(6):758–769.
  • 14. Besson P, Andermann F, Dubeau F, Bernasconi A. Small focal cortical dysplasia lesions are located at the bottom of a deep sulcus. Brain 2008;131(Pt 12):3246–3255.
  • 15. Régis J, Tamura M, Park MC, et al. Subclinical abnormal gyration pattern, a potential anatomic marker of epileptogenic zone in patients with magnetic resonance imaging-negative frontal lobe epilepsy. Neurosurgery 2011;69(1):80–93.
  • 16. Palmini A, Gambardella A, Andermann F, et al. Intrinsic epileptogenicity of human dysplastic cortex as suggested by corticography and surgical results. Ann Neurol 1995;37(4):476–487.
  • 17. Cunningham DJ. Text-book of anatomy. New York, NY: Wood, 1905.
  • 18. Ono M, Kubik S, Abernathey CD. Atlas of the cerebral sulci. Stuttgart, Germany: Thieme, 1990.
  • 19. Hamasaki T, Imamura J, Kawai H, Kuratsu J. A three-dimensional MRI study of variations in central sulcus location in 40 normal subjects. J Clin Neurosci 2012;19(1):115–120.
  • 20. Yousry TA, Schmid UD, Alkadhi H, et al. Localization of the motor hand area to a knob on the precentral gyrus: a new landmark. Brain 1997;120(Pt 1):141–157.
  • 21. Gay O, Plaze M, Oppenheim C, et al. Cortex morphology in first-episode psychosis patients with neurological soft signs. Schizophr Bull 2013;39(4):820–829.
  • 22. Mangin JF, Rivière D, Cachia A, et al. A framework to study the cortical folding patterns. Neuroimage 2004;23(Suppl 1):S129–S138.
  • 23. Chassoux F, Landré E, Mellerio C, et al. Type II focal cortical dysplasia: electroclinical phenotype and surgical outcome related to imaging. Epilepsia 2012;53(2):349–358.
  • 24. Van Essen DC. A tension-based theory of morphogenesis and compact wiring in the central nervous system. Nature 1997;385(6614):313–318.
  • 25. Rakic P. Specification of cerebral cortical areas. Science 1988;241(4862):170–176.
  • 26. Winston GP, Micallef C, Symms MR, Alexander DC, Duncan JS, Zhang H. Advanced diffusion imaging sequences could aid assessing patients with focal cortical dysplasia and epilepsy. Epilepsy Res 2013;108(2):336–339.
  • 27. Bronen RA, Spencer DD, Fulbright RK. Cerebrospinal fluid cleft with cortical dimple: MR imaging marker for focal cortical dysgenesis. Radiology 2000;214(3):657–663.
  • 28. Colombo N, Tassi L, Deleo F, et al. Focal cortical dysplasia type IIa and IIb: MRI aspects in 118 cases proven by histopathology. Neuroradiology 2012;54(10):1065–1077.
  • 29. Naidich TP, Brightbill TC. The pars marginalis. I. A “bracket” sign for the central sulcus in axial plane CT and MRI. Int J Neuroradiol 1996;2(1):3–19.
  • 30. Hingwala D, Thomas B, Radhakrishnan A, Suresh Nair N, Kesavadas C. Correlation between anatomic landmarks and fMRI in detection of the sensorimotor cortex in patients with structural lesions. Acta Radiol 2014;55(1):107–113.
  • 31. Yang JC, Aronson JP, Dunn GP, Codd PJ, Buchbinder BR, Eskandar EN. Three-dimensional brain surface visualization for epilepsy surgery of focal cortical dysplasia. J Clin Neurosci 2014;21(7):1230–1232.
  • 32. Wagner M, Jurcoane A, Hattingen E. The U sign: tenth landmark to the central region on brain surface reformatted MR imaging. AJNR Am J Neuroradiol 2013;34(2):323–326.
  • 33. Montenegro MA, Li LM, Guerreiro MM, Guerreiro CA, Cendes F. Focal cortical dysplasia: improving diagnosis and localization with magnetic resonance imaging multiplanar and curvilinear reconstruction. J Neuroimaging 2002;12(3):224–230.
  • 34. Sun ZY, Klöppel S, Rivière D, et al. The effect of handedness on the shape of the central sulcus. Neuroimage 2012;60(1):332–339.
  • 35. Vovk U, Pernus F, Likar B. A review of methods for correction of intensity inhomogeneity in MRI. IEEE Trans Med Imaging 2007;26(3):405–421.

Article History

Received April 8, 2014; revision requested June 6; final revision received July 3; accepted July 16; final version accepted July 29.
Published online: Sept 19 2014
Published in print: Feb 2015