Reversible focal MRI abnormalities due to status epilepticus. An EEG, singlephoton emission computed tomography, transcranial Doppler follow-up study

Csaba Juha´sz*, Erika Scheidl, Imre Szirmai

Department of Neurology, Semmelweis University of Medicine, H-1083 Budapest, Balassa u. 6, Hungary

Accepted for publication: 20 May 1998

Abstract

We demonstrate clinical data and findings of MRI, transcranial Doppler (TCD), single photon emission computed tomography (SPECT)and electroencephalography (EEG) in an 8 month follow-up study of a 15 year old girl who developed focal status epilepticus with sensoryand visual illusions. EEG showed right temporal and occipital seizure activity and attenuation of the alpha activity with right predominance.MRI showed a right temporo-parietal hyper signal on the T2 weighted images involving the cortex with sulcal effacement. MRI-angio-graphy suggested insufficient flow in the right transverse sinus. TCD detected an elevated flow velocity in the ipsilateral middle cerebralartery during status epilepticus, corresponding to an increased perfusion of the epileptic area revealed by SPECT. After normalization of theTCD finding, the MRI detected persistent cortical abnormality beyond the 70th day after admission. MRI normalized on the 103rd day offollow-up. Serial EEG frequency analysis demonstrated the recovery of alpha peak frequency on the left side, but the attenuation ofrhythmic signals remained persistent on the right. In our case, the restitution of postictal EEG lag behind the consolidation of MRI signalabnormality. 1998 Elsevier Science Ireland Ltd. All rights reserved

Keywords:Focal epilepsy; Focal status epilepticus; MRI; Transcranial Doppler; Electroencephalography; Follow-up

1. Introduction

There are several reports on reversible MRI pathologyfollowing focal status epilepticus (Kramer et al., 1987;Riela et al., 1991; Takamatsu et al., 1991; De Carolis etal., 1992; Lee et al., 1992; Henry et al., 1994; Cox et al.,1995; Stubgen, 1995; Chan et al., 1996) even after singleseizures (Yaffe et al., 1995). The time course of signalabnormality is variable but does not persist for longer than2 months. These observations suggest that pathological sig-nals can be the consequence of cortical discharging lesions,rather than the cause of them (Rao et al., 1995). Long-termfollow-up of electroencephalography (EEG) after the recov-ery of postictal MRI pathology has not been published.Single photon emission computed tomography (SPECT)can demonstrate peri-ictal hyperperfusion of the epilepticarea (Jabbari et al., 1991). Transcranial Doppler (TCD) is a

non-invasive method for monitoring blood flow in largecerebral vessels. There are some studies demonstratingincreased blood flow velocity in the nutritive arteries ofthe epileptic focus (Wilder-Smith and Nirkko, 1991;Bode, 1992). However, changes of flow velocity in the mid-dle cerebral artery during and after focal status epilepticushas not so far been reported. We followed one patient withnon-convulsive focal status epilepticus using MRI, quanti-tative EEG, TCD and SPECT. During the 8 month follow-up, we wanted to clarify the time course of changes reflectedby the various investigating methods.

2. Case report

A 15 year old girl was born premature with asphyxia,hyperbilirubinaemia and anaemia, weighing 1900 g. Shedeveloped two generalized tonic–clonic seizures 3 weeksbefore admission to the department. After the termination ofgeneralized seizures she felt continuous numbness and par-esthesia on the left arm and face, associated with frequent

Electroencephalography and clinical Neurophysiology 107 (1998) 402–407

0013-4694/98/$ - see front matter 1998 Elsevier Science Ireland Ltd. All rights reservedPII : S0013-4694(98)00089-3 EEG 97783

* Corresponding author. Tel./fax: +36 1 2100337;e-mail: jucsab@neur.sote.hu