Paul Ruggieri

Successful surgery for epilepsy due to early brain lesions despite generalized EEG findings

Objective: To understand the role of epilepsy surgery in children with generalized or bilateral findings on preoperative scalp EEG. Methods: From our pediatric epilepsy surgery series, we identified 50 patients in whom 30 to 100% of preoperative epileptiform discharges (ictal, interictal, or both) were generalized or contralateral to the side of surgery. Results: All patients had severe refractory epilepsy and an epileptogenic lesion on brain MRI. Ninety percent of the lesions were congenital, perinatal, or acquired during infancy, predominantly malformations of cortical development (44%) or cystic encephalomalacia (40%). Age at surgery was 0.2 to 24 (median 7.7) years. Surgeries were hemispherectomy (64%) or lobar or multilobar resection. At last follow-up (median 24.0 months), 72% of patients were seizure-free, 16% had marked improvement with only brief episodes of staring or tonic stiffening, and 12% were not improved. The rate of seizure-free outcome was not significantly associated with age at seizure onset or surgery, presence of hemiparesis or focal clinical features during seizures, type of lesion, or surgery type. Postoperative seizure-free rate did not differ from that in a comparison group of similar patients who matched the study group except for their high percentage (70 to 100%) of ipsilateral ictal and interictal epileptiform discharges on preoperative EEG. Conclusions: Epilepsy surgery may be successful for selected children and adolescents with a congenital or early-acquired brain lesion, despite abundant generalized or bilateral epileptiform discharges on EEG. The diffuse EEG expression may be due to an interaction between the early lesion and the developing brain.

Epilepsy Surgery in Infants

Purpose: We report 12 infants who had frontal (n = 3), temporal (n = 2), or temporoparieto‐occipital (n = 2) resection or functional hemispherectomies (n = 5) at age 2.5–29 (mean 15.3) months for catastrophic epilepsy due to focal cortical dysplasia (n = 5), Sturge‐Weber syndrome (n = 3), ganglioglioma (n = 3), or hemimegalencephaly (n = 1). Seizures began at 1 day to 14 months (mean, 4.0 months) after birth, occurred frequently (often many times per day, and were refractory to antiepileptic drugs. Patients were evaluated for surgery at 2.5–24 (mean 12.4) months of age. Seven patients had hemiparesis and eight had slowed cognitive development. Seizures were characterized by arrest or marked reduction of behavioral motor activity with unclear level of consciousness (n = 4, with temporal or temporoparietal EEG seizures), focal clonic activity (n = 3, with perirolandic EEG seizures), generalized tonic stiffening (n = 3, with temporoparieto‐occipital, parietal, or frontal EEG seizures), or infantile spasms and hypsarrhythmia (n = 2, with a frontal tumor or temporoparieto‐occipital cortical dysplasia).

Temporal lobe epilepsy due to hippocampal sclerosis in pediatric candidates for epilepsy surgery

Objective: To characterize the clinical, EEG, MRI, and histopathologic features and explore seizure outcome in pediatric candidates for epilepsy surgery who have temporal lobe epilepsy (TLE) caused by hippocampal sclerosis (HS). Methods: The authors studied 17 children (4 to 12 years of age) and 17 adolescents (13 to 20 years of age) who had anteromesial temporal resection between 1990 and 1998. Results: All patients had seizures characterized by decreased awareness and responsiveness. Automatisms were typically mild to moderate in children and moderate to marked in adolescents. Among adolescents, interictal spikes were almost exclusively unilateral anterior temporal, as opposed to children in whom anterior temporal spikes were associated with mid/posterior temporal, bilateral temporal, extratemporal, or generalized spikes in 60% of cases. MRI showed hippocampal sclerosis on the side of EEG seizure onset in all patients. Fifty-four percent of children and 56% of adolescents had significant asymmetry of total hippocampal volumes, whereas the remaining patients had only focal atrophy of the hippocampal head or body. Subtle MRI abnormalities of ipsilateral temporal neocortex were seen in all children and 60% of adolescents studied with FLAIR images. On histopathology, there was an unexpectedly high frequency of dual pathology with mild to moderate cortical dysplasia as well as HS, seen in 79% of children and adolescents. Seventy-eight percent of patients were free of seizures at follow-up (mean, 2.6 years). A tendency for lower seizure-free outcome was observed in patients with bilateral temporal interictal sharp waves or bilateral HS on MRI. The presence of dual pathology did not portend poor postsurgical outcome. Conclusions: TLE caused by HS similar to those in adults were seen in children as young as 4 years of age. Focal hippocampal atrophy seen on MRI often was not reflected in total hippocampal volumetry. Children may have an especially high frequency of dual pathology, with mild to moderate cortical dysplasia as well as HS, and MRI usually, but not always, predicts this finding. Postsurgical seizure outcome is similar to that in adult series.

Seizure outcome after epilepsy surgery in patients with normal preoperative MRI

Objective: To determine outcome after epilepsy surgery in patients with normal preoperative magnetic resonance imaging (MRI). Methods: 24 adult and paediatric patients with normal preoperative MRIs were studied. They underwent epilepsy surgery between 1994 and 2001 and had at least one year of follow up. Results: At the most recent follow up, nine patients (37%) were seizure-free and 18 (75%) had at least a 90% reduction in seizure frequency with weekly or monthly seizures. Seizure freedom was not significantly different after resections in frontal (5/9) or temporal regions (4/13) (p = 0.24, Fisher’s exact test), or among patients with or without localising features on EEG, PET, or ictal SPECT. Subdural grids, used in 15 of 24 patients, helped tailor resections but were not associated with differences in outcome. Histopathology showed cortical dysplasia in 10 patients (42%), non-specific findings in 13 (54%), and hippocampal sclerosis in one (4%). Cortical dysplasia was seen in seven patients with frontal resection (78%) and non-specific findings in nine (69%) with temporal resection. Seizure outcome did not differ on the basis of location of resection or histopathology. Conclusions: While these results were less favourable than expected for patients with focal epileptogenic lesions seen on MRI, they represented worthwhile improvement for this patient population with high preoperative seizure burden. In this highly selected group, no single test or combination of tests further predicted postoperative seizure outcome.

Strategies for the Safe Magnetic Resonance Imaging of Pacemaker-Dependent Patients

Objective: To determine if strategies used to safely scan nonpacemaker‐dependent patients could be applied to facilitate safe MRI of pacemaker‐dependent patients.

Postictal Diffusion-Weighted Imaging for the Localization of Focal Epileptic Areas in Temporal Lobe Epilepsy

Summary:  Purpose: Diffusion‐weighted MR imaging (DWI) is a novel technique to delineate focal areas of cytotoxic edema of various etiologies. We hypothesized that DWI may also detect the epileptogenic region and adjacent areas during the ictal and early postictal periods in patients with temporal lobe epilepsy (TLE).

Periictal diffusion-weighted imaging in a case of lesional epilepsy.

Summary: Purpose: Diffusion‐weighted MR imaging (DWI) has been used for the early diagnosis of acute ischemic lesions in humans and in animal models of focal status epilepticus. We hypothesized that DWI may be a sensitive, noninvasive tool for the localization of the epileptogenic area during the periictal period.

Diagnosis of cerebrovascular disease in sickle cell anemia by magnetic resonance angiography

The study of blood flow by means of magnetic resonance techniques has led to a noninvasive magnetic resonance angiography (MRA) technique for imaging large cerebral vessels. Ten children with sickle cell hemoglobinopathy and a history of acute neurologic syndromes were studied with combined parenchymal magnetic resonance imaging (MRI) and MRA. Six had abnormal MRI findings and MRA-defined luminal lesions in the vascular distribution of these parenchymal infarctions. The three children with previous intraarterial angiography had MRA abnormalities that corresponded with vascular lesions on conventional angiograms. Four had normal MRI and MRA findings. We conclude that a combination of MRI and MRA provides a noninvasive screening test for large-vessel disease in this population.

Steroid-responsive encephalopathy associated with autoimmune thyroiditis and primary CNS demyelination

Steroid responsive encephalopathy associated with autoimmune thyroiditis is a well-recognized complication of autoimmune thyroid disease. However, the characterization of the histopathological features of steroid responsive encephalopathy associated with autoimmune thyroiditis are limited to six cases. Reported pathological features include vasculitis involving venules and arterioles, lymphocytic perivascular cuffs and microglial activation. We report a case of SREAT with biopsy proven (on two occasions) primary CNS demyelination and radiological evidence of steroid responsiveness, identifying primary CNS demyelination as a complication of autoimmune thyroid disease.

Neocortical temporal FDG-PET hypometabolism correlates with temporal lobe atrophy in hippocampal sclerosis associated with microscopic cortical dysplasia

Summary:  Purpose: Medically intractable temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), with or without cortical dysplasia (CD), is associated with atrophy of the hippocampal formation and regional fluorodeoxyglucose positron‐emission tomography (FDG‐PET) hypometabolism. The relation between areas of functional and structural abnormalities is not well understood. We investigate the relation between FDG‐PET metabolism and temporal lobe (TL) and hippocampal atrophy in patients with histologically proven isolated HS and HS associated with CD.