MRI changes and their prognostic value in status epilepticus

Status epilepticus (SE) is a neurological emergency associated with a high rate of mortality and morbidity. The longer status epilepticus lasts the higher is the chance for nerve cells of the brain to get damaged, loose their function and eventually die. Therefore, the treatment of SE should start as early as possible. Some forms of SE are relatively easy to treat. In some types of SE, however, the seizure activity persists despite the usage of multiple antiseizure drugs. Brain imaging, especially magnetic resonance imaging (MRI) is an essential part of a diagnostic work- up of patients with SE. Some patients with SE develop changes on MRI, which are caused by ongoing seizure activity. These changes may persist or disappear within of days after onset of SE. It is not clear, however, why only some patients develop SE associated MRI changes. It is also not well established whether there are specific patterns of MRI abnormalities caused by SE. Other open questions are related to the behavior of MRI changes in SE over time: 1) is the severity of SE associated with the persistent MRI abnormalities? 2) could MRI changes predict the prognosis and outcome of SE? 3) will patients with persistent MRI changes develop irreversible brain damage, for instance, atrophy of some brain structures? In order to answer these questions, we are planning to recruit in prospective manner 230 patients with SE at the Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University of Salzburg. Many of these patients will undergo MRI due to their clinical needs. In case if patients have SE-associated changes, they will undergo follow-up MRIs one week and one month after the onset of SE. These MRI will be thoroughly analyzed by two independent expert neuroradiologists. The results will be compared with the MRIs of two control groups: 1) patients who have epilepsy and single seizures (not SE) and 2) patients who have MRI changes, but no epilepsy or SE. MRIs of all study participants (patients with SE and control group patients) will undergo sophisticated analyses of MRIs by different software in order to look for aberrant connections between different parts of the brain and signs for brain atrophy. MRI changes will be correlated to the clinical and electroencephalographic data of patients with SE. We hypothesize that 1) SE is associated with specific patterns of MRI changes, 2) most of these changes disappear within one or latest four weeks after the onset of SE, 3) widespread and persisting MRI changes are linked with severe course of SE and unfavorable outcome. Therefore, we expect that the results of this study will help us to define an MRI prognostic marker of SE, which in itself may have an important implication for treatment of patients with SE.

Status epilepticus (SE) is the most severe expression of epileptic seizures. In fact, it is a continuous seizure and is associated with significantly increased mortality and morbidity. Therefore, it is of decisive importance to timely diagnose SE and treat it effectively in order to avoid its serious consequences for patients' health. The diagnosis of SE is based in the most cases on clinical manifestations and an electroencephalography (EEG). However, in some cases, the clinical picture is non-specific and the EEG is equivocal. In such instances, a magnetic resonance imaging (MRI) - a modern technique enables diagnosing SE and is useful in predicting its outcome. The aim of this study was to characterize MRI features of SE and to determine their diagnostic and prognostic value. During four years of the study, we prospectively identified and recruited over 400 patients with different types of SE who underwent an MRI in an acute setting within 48 hours after the diagnosis. About half of these patients had MRI abnormalities caused by SE, so called "peri-ictal MRI abnormalities" - PMA. We performed follow-up MRIs in those patients who had PMA 1 week and 4 weeks after the initial MRI in order to observe the behavior of PMA over time. In the vast majority of patients who presented with non-motor manifestations of SE, an MRI was helpful in supporting the diagnosis of SE. In our large cohort, we could determine the specific location of PMA in the human brain. We were able also to distinguish between MRI features of SE and MRI abnormalities due to other common conditions such as stroke by quantifying the MRI aberrations. Comprehensive analysis of our cohort allowed us to determine the clinical parameters that were associated with persistent MRI abnormalities and therefore, with the potential damage of the brain due to SE. In other words, PMA appear to serve as a reliable biomarker for the potential brain injury as a result of SE. In summary, based on our unique and internationally the largest prospective imaging database of patients with SE, we could determine the important role of MRI in diagnosing unclear cases of suspected SE. MRI alterations related to SE serve as reliable biomarker for determining the outcome of SE. Our results open new avenues for early and precise diagnosing of SE and tailoring treatment strategies based on imaging features of SE.