J Neurol (1989) 236:296-299 Journal of

Neurology © Springer-Verlag 1989

CT, MRI and SPECT neuroimaging in status epilepticus with simple partial and complex partial seizures: case report

J. Bauer i, H. Stefan I , W . J . Huk 2 , H. Feistei 3, M.-J. Hilz l, H.-G. Brinkmann l, K.-F. Druschky l, and B. Neund6rfer 1

l Neurologische Klinik mit Poliklinik, Schwabachanlage 6, 2 Abteilung ftir Neuroradiologie, 3 Institut for Nuklearmedizin, Universit~it Erlangen-Ntirnberg, D-8520 Erlangen, Federal Republic of Germany

Summary. A 35-year-old female patient suffering from epilepsy was examined during status epilepticus with simple partial and complex partial seizures by means of EEG, CT, MRI and ictal SPECT. All these examinations showed focal abnormalities with identical location due to oedema and hypervascularisa- tion; these were, however, absent during examinations carried out before and after status epilepticus.

Key words: Status epilepticus - Computed tomography - Magnetic resonance imaging - Single-photon emission com- puted tomography - Cerebral oedema

Introduction

In addition to clinical examination and electroencephalography (EEG), new neuroimaging methods are important in ascertain- ing the cause of epilepsy. Computed tomography (CT) and magnetic resonance imaging (MRI) are used to show cerebral lesions, whereas single-photon computed tomography (SPECT) and positron emission tomography (PET) are used to detect functional disturbances. In addition to interictal findings, the results of recent ictal investigations have occasionally been published. Nevertheless, there are no studies of status epilep- ticus in which ictal SPECT, CT, MRI measurements and inten- sive EEG monitoring have all been carried out on the same patient.

Case report

A 35-year-old female patient whose mother's pregnancy had been normal was born after protracted labour. She had been deaf since birth. Psychomotor development was retarded. Be- haviour was aggressive. Epileptic seizures were associated with limited intellectual and motor performance. At school she had suffered from repeated "fits"; definite epileptic sei- zures first appeared at the age of 25 years. Tonic-clonic sei- zures, complex partial seizures and myoclonic seizures had been observed. When the patient was transferred to our clinic, she had been suffering from status epilepticus for 2 days.

Offprint requests" to," J. Bauer

Clinical findings

Between seizures, the patient was awake and followed orders, as far as she understood them. Neurological examination re- vealed deafness and increased response of tendon reflexes on the left side.

The distribution and duration of seizures over 24 h, derived from long-term EEG monitoring are shown in Fig. 1.

The seizures started with a perioral tonic tensing of the facial muscles, more pronounced on the left side. Myoclonia then began on the upper and lower left eyelids, spreading to the left cheek and the right eyelid. Myoclonia did not extend to the rest of the body. Consciousness was impaired in 50% of seizures. Seizures were classified as simple partial and complex partial seizures.

The interictal EEG showed a slowing down of background activity. A slow-wave and sharp-wave focus was present in the right fronto-centro-temporal region. Seizure onset was charac- terized by 9Hz rhythmic activity in the right fronto-centro- temporal region (Fig. 2). Rhythmic activity sometimes also ex- tended into the left hemisphere.

An ictal SPECT examination was performed on the 3rd 99 rn day of status epilepticus. TC-hexamethyl-propylene amine

oxime (HMPAO) was injected 20 s after seizure onset as shown by the EEG. The SPECT recording followed 1 h later using a double-headed scintillation camera (Rotacamera, Siemens) with a high resolution collimator and a spatial resolution of at least 1.5 cm, even in deeper brain layers. A marked hyperper- fusion in the right central region was found (Fig. 3).

A CT scan taken on the 3rd day of status epilepticus showed cortical and subcortical atrophy. Swelling of the right frontal hemisphere was evident from the narrow sulci. Hypodensity was present in the right fronto-central area (Fig. 4a). CT exami- nation 10 weeks later, 2 weeks after cessation of status epilep- ticus, showed narrow sulci in the right frontal hemisphere; the hypodense area was no longer present (Fig. 4b).

MRI was performed on the 5th day of status epilepticus. On Tl-weighted images, the sulci in the right fronto-central area were blurred. The grey/white matter distinction was not clear. The white matter in the same area was swollen (Fig. 5a). After intravenous injection of gadolinium, the grey matter signal in the right fronto-central region was partly enhanced (Fig. 5b). On MRI examination, carried out 3 months previ- ously, these pathological findings were not present (Fig. 5c).

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Fig. 1. Distribution and duration of sei- zures over 24 h, based on long-term EEG. , Rhytmic EEG activity in the fight hemisphere; . . . . , rhythmic EEG activity in both hemispheres

Fig, 2. Seizure onset in long-term EEG in the fight fronto-centro-temporal re- gion (F4-C4; C4-P4; F8-T4)

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Fig. 3. Ictal SPECT measurement, horizontal view; r, fight; l, left

Fig.4. CT scan (Somatom DRH): a 3rd day of status epilepticus, h 2 weeks after cessation of seizures. R, Right; L, left

Fig.5. MRI images (Magnetom; a, b: 1.5 Tesla; e 1.0 Tesla). a T1- weighted image, 5th day of status epilepticus, b T1-weighted image, 5th day of status epilepticus after injection of gadolinium, c T2-weighted image, 6 months before status epilepticus. R, Right; L, left

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Discussion

The importance of new neuroimaging methods in the interictal diagnosis of the aetiology of epilepsy, especially with focal sei- zures, is well known. Through regular CT scanning, the number of pathological findings may be increased by 20%, to 50% of all cases [ 11, 18].

Nevertheless, the E E G is still important for diagnosing epilepsy [5]. The interictal findings in E E G and CT scans cor- respond in 52% of cases [1].

Compared with CT scanning, MRI increases the number of pathological findings, especially in epilepsies with complex partial seizures. This is of great importance, especially for the investigation of intractable seizures [2, 6, 16]. Interictal SPECT measurements in patients with focal epilepsies have demon- strated one or more hyperperfused brain regions in up to 90% of cases [15, 24, 25].

A focal hypometabolism of glucose can be shown by inter- ictal PET investigations [10, 12, 28]. Comparative studies in focal epilepsies have shown localized abnormalit ies in PET studies (almost always), in MRI (less often) and in CT or SPECT (only rarely) [13, 25].

Ictal neuroimaging investigations have, up to now, only been reported occasionally. Ketz and Meier [8] examined two pa- tients suffering from tonic-clonic status epilepticus. CT showed diffuse brain oedema. Focal hypodensities in ictal or postictal CT scans have been described by some investigators. In some cases these findings gave cause for further examination, includ- ing brain biopsy. This was the case when focal abnormalit ies were suspected to be vascular, inf lammatory or neoplastic. It is agreed that the focal pathological findings on CT are caused by oedema, due to increased vascular permeabili ty [4, 7, 9, 23, 301.

Stone et al. [27] investigated a patient during status epilep- ticus with complex partial seizures, using CT, MRI and angio- graphy. Both CT and MR! showed oedema identically located, comparable with our findings. Cerebral angiography has dem- onstrated a hypervascular pattern consisting of arteriolar or capillary blush with early filling veins, corresponding to the focus in CT and MRI [27, 29]. Similar findings have been de- scribed by Lee and Goldberg [14]. After arrest of seizure ac- tivity, repeated angiograms no longer showed the hypervascular pattern. The mechanism underlying the hypervascular pattern is not known. Perhaps increased oxygen consumption in the cortical epileptogenic site and resultant hypoxia lead to accumu- lation of CO2 and lactic acid, which in turn causes vasodilata- tion, loss of autoregulat ion and increased cerebral blood flow. i t is also possible that a rise in systemic blood pressure during seizure activity, as demonstrated in animals by Plum et al. [21], leads to temporary loss of autoregulation and increased cerebral blood flow. Penfield [19, 20] noticed a regional cortical hyper- perfusion when epileptic seizures appeared during surgery.

In our investigations, a focal hypervascularisation was dem- onstrated by SPECT (Fig. 3) and MRI (Fig. 5b). Lee et al. [15] also examined patients suffering from focal status epilepticus using SPECT and were able to show regional hyperperfusion corresponding to the E E G focus. Even during isolated epileptic seizures, ictal SPECT examinat ion has revealed focal hyper- perfusion [22, 26]. Ictal findings in PET images have occasion- ally been reported [3, 17].

Transient pathological findings in neuroimaging during status epilepticus may appear due to oedema. This may lead to the false diagnosis of vascular, neoplastic or inflammatory

disease. As shown by us and other investigators, it is clear that the focal oedema shown by neuroimaging methods during status epilepticus is reverisble. Repeated examinations therefore are helpful in excluding other diseases.

Acknowledgements. We thank Ms B.Winheim for her help in long- term EEG recording and Dr. Buchholz and colleagues, Erlangen, for their kind permission to publish Fig. 5c.

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Received November 28, 1988 / Received in revised form January 25, 1989 / Accepted February 2, 1989