Imaging Studies After Seizures

Objective:To investigate the imaging manifestations induced by seizures, in order to provide evidences for rational diagnosis and differential diagnosis.Methods:Imaging data of291cases of various types of epilepsy admitted to Xiangya Hospital of Central South University from January2012to March2014were investigated retrospectively. The brain MRI (Magnetic resonance imaging, MRI) of all patients had been reviewed by two or more than two doctors (including neurology and magnetic resonance chamber).The clinical data and EEG (electroencephalogram, EEG) data of patients with abnormal brain MRI changes caused by seizures were summarized and analyzed retrospectively. We summarized the frequency of seizures, seizure types and epileptic MRI changes in the common parts, features, prognosis, the relationship between the lesion site and EEG discharge site in patients with abnormal MRI caused by seizures.Results:1. Cases selected:Based on patient history, test results related to clinical manifestations, laboratory tests, brain magnetic resonance venography (MRV), cerebral digital subtraction angiography (DSA) technology and cerebrospinal fluid examination, we ruled out brain MRI abnormalities caused by cerebral infarction for8cases, post-traumatic brain injury for15cases, encephalitis for12cases, tumor for5cases, venous sinus thrombosis for3cases, metabolic diseases for cases. A total of46cases which did not meet the diagnostic criteria were excluded, and245cases were enrolled finally.2. The frequency of seizures, seizure types in patients with abnormal brain MRI changes caused by seizures:245cases of patients enrolled were underwent the examination of MRI, and we discovered brain MRI abnormalities caused by seizures in36patients (14.7%). Among them,39cases with simple partial seizures, and MRI abnormalities were found in5 patients of them(12.8%);51cases with complex partial seizures in, and MRI abnormalities were found in7patients of them(13.7%);66cases with partial seizures with secondary generalized tonic-clonic seizures and MRI abnormalities were found10cases of them(15.2%);55cases with generalized tonic-clonic seizures, MRI abnormalities were found in8cases of them(14.5%);34cases with status epilepticus, MRI abnormalities were found in6cases of them(17.6%). The incidence rates of MRI abnormalities caused by status epilepticus and non-status epilepticus had no difference (P=0.069).3. The MRI features of36cases induced by acute exacerbation of epilepsy:T2-weighted images:31patients with slightly or high signal on T2image, two cases showed equal T2signal change; fluid-attenuated inversion recovery (FLAIR) sequences examination:35cases showed high signal changes, one case showed equal signal; Diffusion-weighted imaging (DWI) sequence of examination:13cases showed high signal changes,2case showed equal signal and21cases did not inspect this sequence; MRI enhanced scan:1patient had a partial strengthening the brain parenchyma,14cases showed no enhanced and21patients did not undergo enhanced scan. The MRI abnormalities induced by epileptic seizures in acute phase mainly presented high T2signal, FLAIR hyperintensity and DWI sequence examination early had a good diagnostic capabilities to patients with abnormal MRI caused by seizures.4. Lesion site:12cases involving the cortex;8cases involving the subcortical white matter;4cases involving the hippocampus;2cases involving the brain damage surrounding; distant parts:3cases involving the thalamus,2cases involving the corpus callosum, two cases involving the putamen,1case involving the lenticular nucleus and tail caudate nucleus,2cases involving the cerebellum. Lesions mainly involved cortical and subcortical white matter.Lesion characteristics:MRI changes similar to cerebral infarction were found in10cases, and4cases were misdiagnosed; MRI changes similar to tumor mass were found in2cases, and1cases were misdiagnosed; MRI changes similar to venous sinus thrombosis were found in1cases, and1cases were misdiagnosed; MRI changes similar to mitochondrial encephalopathy were found in5cases, and1cases were misdiagnosed; MRI changes similar to viral encephalitis were found in13cases, and6cases were misdiagnosed; MRI changes similar to reversible posterior leukoencephalopathy syndrom were found in5cases and1cases were misdiagnosed.5. Follow-up MRI:Among the MRI abnormalities caused by seizures of36cases patients,32patients were performed follow-up MRI within90days, and the lesions of25patients (78.1%) completely wer reversible, two cases (6.3%) appeared partially reversible, and5cases (15.6%) lesions appeared completely irreversible; another4cases were lost.6. The relationship between lesion site and EEG:The site of MRI abnormalities site consistented with the EEG discharge site in27patients, and EEG discharge site was located near the brain lesions lobe while lesion site located in the hypothalamus, hippocampus, putamen, caudate nucleus, corpus callosum, cerebellum and other distant sites on MRI in9patients.Conclusions:1. Both status epilepticus and non-status epilepticus seizures could cause abnormal brain MRI signal changes.2. The abnormal brain MRI lesion site caused by seizures was non-specific, it could present as the near epileptic foci, but also for distant parts.3. Abnormal brain MRI caused by seizures could show a transient change in the majority, but also occured completely irreversible change.