Diffusion-weighted and perfusion MRI demonstrates parenchymal changes in complex partial status epilepticus

Abstract

Diffusion-weighted MRI (DWI) and perfusion MRI (PI) have been mainly applied in acute stroke, but may provide information in the peri-ictal phase in epilepsy patients. Both transient reductions of brain water diffusion, namely a low apparent diffusion coefficient (ADC), and signs of hyperperfusion have been reported in experimental and human epilepsy case studies. We studied 10 patients with complex partial status epilepticus (CPSE) with serial MRI including DWI and PI. All patients showed regional hyperintensity on DWI, and a reduction of the ADC in (i) the hippocampal formation and the pulvinar region of the thalamus (six out of 10 patients), (ii) the pulvinar and cortical regions (two out of 10), (iii) the hippocampal formation only (one out of 10), and (iv) the hippocampal formation, the pulvinar and the cortex (one out of 10). In all patients a close spatial correlation of focal hyperperfusion with areas of ADC/DWI change was present. In two patients hyperperfusion was confirmed in additional SPECT (single photon emission computed tomography) studies. All patients received follow-up MRI examinations showing partial or complete resolution of diffusion and perfusion abnormalities depending on the length of the follow-up interval. The clinical course, EEG and SPECT results all indicate that MRI detected changes related to prolonged epileptic activity. Combined PI and DWI can visualize haemodynamic and tissue changes after CPSE in the hippocampus, thalamus and affected cortical regions.

Cortical Regional Hyperperfusion in Nonconvulsive Status Epilepticus Measured by Dynamic Brain Perfusion CT

“…12,24 In contrast, in stroke, the core of an infarction shows an rCBF reduction exceeding 80% compared with the other hemisphere, 30 and the defined threshold for a penumbra requires a minimal rCBF reduction of 34%. 31 Second, the distribution of focal perfusion changes differs between NCSE and stroke: Concordant with the concept of cortical generation of epileptic activity and with previous MR imaging and CBF-SPECT studies, 13,14 ictal hyperperfusion is predominantly present in the cortex and may encompass multiple vascular territories (Fig 3). 32,33 Acute stroke presenting with epileptic seizures or status epilepticus at onset has been reported, 34 but we did not encounter such etiologies in our series.…”

“…9 Because epileptic activity causes an increased metabolic demand in the involved cerebral cortex, which is accompanied by temporarily increased regional brain perfusion, 10,11 measuring cerebral perfusion has become a widely accepted method for localizing the zone of ictal activity. 10,12 In NCSE, hyperperfusion is reported to be confined mainly to the affected cortex without significant white matter involvement 13,14 and focal cortical hyperperfusion tends to encompass widespread areas of the affected hemisphere if consciousness is reduced. 15,16 Thus, we investigated retrospectively 19 patients after a preceding epileptic seizure with persistent altered mental status with perfusion CT (PCT) and EEG.…”

Reduced Diffusion in a Subset of Acute MS Lesions: A Serial Multiparametric MRI Study

“…In these patients, ADC reductions of 11%-37% have been demon- strated, while signs of increased brain perfusion (due to the high energy demand) were noted in affected tissue. 20 A reduction of the ADC has been detected in different acute neurologic diseases (eg, stroke, 21,22 focal epilepsy, 23 toxic demyelination 24 ). We would favor an inflammatory mechanism that could lead to disturbances of energy metabolism, namely mitochondrial dysfunction, and, in turn, lead to reduced diffusion.…”

Repeated Injection of Contrast Medium Inducing Dysfunction of the Blood-Brain Barrier

“…These abnormal findings cannot be explained by status epilepticus since perfusion-weighted imaging often shows increase at the ictus focus, even though diffusion-weighted imaging often shows cortical high intensity in patients with status epilepticus. 7) In addition, the findings cannot be explained by extensive cerebral infarcts since no occlusion of any branches of the left ICA was detected and perfusion-weighted imaging demonstrated normal intravascular blood flow in its territory. Considering all findings, toxic encephalopathy caused by the contrast medium might have occurred in the territory where contrast medium was injected repeatedly.…”