Marco Carnì

Diffusion-weighted magnetic resonance imaging in patients with partial status epilepticus

Purpose:  Diffusion‐weighted magnetic resonance imaging (DWI) is used to detect changes in the distribution of water molecules in regions affected by various pathologies. Like other conditions, ictal epileptic activity, such as status epilepticus (SE), can cause regional vasogenic/cytotoxic edema that reflects hemodynamic and metabolic changes. This study describes the electroclinical and neuroimaging findings in 10 patients with partial SE whose DWI evaluation disclosed periictal changes related to sustained epileptic activity.

EEG/fMRI Study of Ictal and Interictal Epileptic Activity: Methodological Issues and Future Perspectives in Clinical Practice

Summary:  Purpose: Electroencephalography/functional magnetic resonance imaging (EEG/fMRI) has been proposed recently as a tool to study electrophysiological activity and, consequently, detect brain regions activated during epileptiform EEG abnormalities. The purpose of the study was to review our two‐year experience with studying ictal and interictal activities in patients with epilepsy.

Drug resistant ADLTE and recurrent partial status epilepticus with dysphasic features in a family with a novel LGI1mutation: electroclinical, genetic, and EEG/fMRI findings.

Purpose:  We characterized a family with autosomal dominant lateral temporal epilepsy (ADLTE) whose proband presented uncommon electroclinical findings such as drug‐resistant seizures and recurrent episodes of status epilepticus with dysphasic features.

Metabolic correlatives of brain activity in a FOS epilepsy patient

The correlation and the interactions between neuronal activity and underlying metabolic dynamics are still a matter of debate, especially in pathological conditions. This study reports findings obtained on a subject suffering from fixation‐off sensitivity (FOS) epilepsy, exploited as a model system of triggerable anomalous electrical activity. Functional Magnetic Resonance Spectroscopy was used to investigate the metabolic response to visual spike‐inducing stimuli in a single voxel placed in the temporo‐occipital lobe of a FOS epilepsy patient. MRS measurements were additionally performed on a control group of five healthy volunteers. The FOS patient also underwent an EEG session with the same stimulus paradigm. Uniquely in the FOS patient, glutamate and glutamine concentration increased during the first 10 min of stimulation and then returned to baseline. On the other hand, FOS‐induced epileptic activity (spiking) endured throughout all the stimulation epoch. The observed metabolic dynamics may be likely linked to a complex interplay between alterations of the metabolic pathways of glutamate and modulation of the neuronal activity. Copyright

Long‐term Reproducibility of fMRI Activation in Epilepsy Patients with Fixation Off Sensitivity

Recently EEG/functional magnetic resonance imaging (f MRI) has been proposed in epilepsy research to study and map electrophysiological activity. It can detect regions in the brain activated during interictal or ictal EEG abnormalities and thus contribute to a clearer understanding of neurophysiologic mechanisms underlying epileptic phenomena (1‐3). However, f MRI studies are limited by a number of factors: some are related to the technique itself (nonstandardized technical approach, heterogeneous procedures used in the experimental paradigms, image processing and statistical analysis, and varying sensitivity of the instrument), whereas others are related to the seizures (unpredictable occurrence, technical problems, and artifact on images in case of motor activity). It may, consequently, be difficult to verify the reproducibility of results over time, as is suggested by the lack of studies focusing on this aspect.

Ictal haemodynamic changes in a patient affected by “subtle” Epilepsia Partialis Continua

We report on a 64 year-old woman presenting with Epilepsia Partialis Continua (EPC) affecting the left hand since the age of 24 without neurological deficit. Structural MRI showed a region of focal cortical dysplasia (FCD) over the right central gyrus and lesions in the mesial frontal and occipital cortex secondary to perinatal hypoxic injury. Ictal spike haemodynamic mapping using simultaneous EEG-fMRI revealed significant BOLD signal changes prominent in the region of FCD (larger cluster), occipital cortex (global statistical maximum), prefrontal cortex and cerebellum. The cluster over FCD was in good agreement with the result of EEG source analysis. Our findings provide an interesting illustration of the ability of EEG-fMRI to reveal epileptogenic networks confirming the intrinsic epileptogenic properties of dysplastic neurons.

Cryptogenic focal epilepsy and "hidden" celiac disease in adulthood: a causal or accidental link?

Purpose. Celiac disease (CD) is an immuno-mediated small bowel disease characterized by chronic inflammation due to a permanent intolerance to gliadin. Several neurological complications have been described, including epilepsy, whose evolution might often improve by adopting gluten-free diet (GFD). We studied a population of adult patients affected by posterior drug-resistant epilepsy of unknown cause by performing an accurate screening for CD. In the selected patients presenting the association of epilepsy and CD, we characterized the related electro-clinical features. Materials and Methods. We consecutively identified 211 adult subjects affected by drug-resistant cryptogenic focal epilepsy with posterior seizures. All these patients underwent serological screening for CD. In 10 subjects positive serological tests allowed to perform a CD diagnosis (confirmed by duodenal biopsy). For each patient clinical and EEG data, neuroimaging studies, serological and histological findings were revised, as well as response to GFD, defined as an improvement in seizure outcome. Results. A significant delay between diagnosis of epilepsy and CD was documented. Visual ictal manifestations were reported in half of subjects. In all cases, interictal EEG showed slow and epileptiform abnormalities over parietal-occipital and temporal regions; in three cases, FOS phenomenon was observed. Four patients had familiar history of CD and six cases showed clinical signs/symptoms of malabsorption. GFD led to a reduction of seizure frequency in half of patients. Conclusions. “Posterior” ictal semiology, peculiar EEG patterns and drug-resistance emerge as the most interesting characteristics. CD screening should be performed in epilepsy patients presenting such features.

A computational tool for evaluating HIFU safety

BACKGROUND High Intensity Focused Ultrasound (HIFU) is a noninvasive treatment for therapeutic applications, in particular the treatment of either benign or malignant tumor lesions. HIFU treatment is based on the power of a focused ultrasound beam to locally heat biological tissues over a necrotic level with minimal impact on the surrounding tissues. Therapies based on HIFU are becoming widely spread in the panorama of options offered by the Health Care System. Consequently, there is an ever increasing need to standardise quality assurance protocols and to develop computational tools to evaluate the output of clinical HIFU devices and ensuring safe delivery of HIFU treatment. AIMS Goal of this study is the development of a computational tool for HIFU ablation therapy to assure safety of the patient and effectiveness of the treatment. RESULTS The simulated results provide information about the behaviour of the focalized ultrasound in their interaction with different biological tissues. CONCLUSIONS Numerical simulation represents a useful approach to predict the heath deposition and, consequently, to assess the safety and effectiveness of HIFU devices.

Dependence of apparent diffusion coefficient measurement on diffusion gradient direction and spatial position – A quality assurance intercomparison study of forty-four scanners for quantitative diffusion-weighted imaging

PURPOSE To propose an MRI quality assurance procedure that can be used for routine controls and multi-centre comparison of different MR-scanners for quantitative diffusion-weighted imaging (DWI). MATERIALS AND METHODS 44 MR-scanners with different field strengths (1 T, 1.5 T and 3 T) were included in the study. DWI acquisitions (b-value range 0-1000 s/mm2), with three different orthogonal diffusion gradient directions, were performed for each MR-scanner. All DWI acquisitions were performed by using a standard spherical plastic doped water phantom. Phantom solution ADC value and its dependence with temperature was measured using a DOSY sequence on a 600 MHz NMR spectrometer. Apparent diffusion coefficient (ADC) along each diffusion gradient direction and mean ADC were estimated, both at magnet isocentre and in six different position 50 mm away from isocentre, along positive and negative AP, RL and HF directions. RESULTS A good agreement was found between the nominal and measured mean ADC at isocentre: more than 90% of mean ADC measurements were within 5% from the nominal value, and the highest deviation was 11.3%. Away from isocentre, the effect of the diffusion gradient direction on ADC estimation was larger than 5% in 47% of included scanners and a spatial non uniformity larger than 5% was reported in 13% of centres. CONCLUSION ADC accuracy and spatial uniformity can vary appreciably depending on MR scanner model, sequence implementation (i.e. gradient diffusion direction) and hardware characteristics. The DWI quality assurance protocol proposed in this study can be employed in order to assess the accuracy and spatial uniformity of estimated ADC values, in single- as well as multi-centre studies.

Behavioral and Movement Disorders due to Long-Lasting Myoclonic Status Epilepticus Misdiagnosed as ADHD in a Patient With Juvenile Myoclonic Epilepsy Electroclinical Findings and Related Hemodynamic Changes

Epilepsy and attention-deficit/hyperactivity disorder (ADHD) likely share common underlying neural mechanisms, as often suggested by both the evidence of electroencephalography (EEG) abnormalities in ADHD patients without epilepsy and the coexistence of these 2 conditions. The differential diagnosis between epilepsy and ADHD may consequently be challenging. In this report, we describe a patient presenting with a clinical association of “tics” and behavioral disorders that appeared 6 months before our first observation and had previously been interpreted as ADHD. A video-EEG evaluation documented an electroclinical pattern of myoclonic status epilepticus. On the basis of the revised clinical data, the EEG findings, the good response to valproate, the long-lasting myoclonic status epilepticus, and the enduring epileptic abnormalities likely causing behavioral disturbances, the patient’s symptoms were interpreted as being the expression of untreated juvenile myoclonic epilepsy. The EEG–functional magnetic resonance imaging study revealed, during clinical generalized spike-and-wave and polyspike-and-wave discharges, positive blood oxygen level–dependent (BOLD) signal changes bilaterally in the thalamus, the prefrontal cortex (Brodmann area 6, supplementary motor area) and the cerebellum, and negative BOLD signal changes in the regions of the default mode network. Such findings, which are typical of BOLD changes observed in idiopathic generalized epilepsy, may also shed light on the anatomofunctional network underlying ADHD.