The status of status: seizures are bad for your brain's health.
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Animals↗
Biomedical subjects
R A Bronen
Publications and source records attributed to R A Bronen.
Hippocampal and limbic terminology.
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Hippocampus↗
Imaging findings in hippocampal sclerosis: correlation with pathology.
We evaluated the ability of preoperative radiologic imaging to detect hippocampal sclerosis in 31 patients who underwent surgery for intractable epilepsy. Hippocampal sclerosis is commonly associated with surgically treatable temporal lobe epilepsy. It is pathologically described as neuronal cell loss with associated gliosis in the hippocampus. While previous reports have correlated imaging results with clinical or qualitative histologic findings, this study used quantitative pathologic criteria (neuronal cell density) to diagnosis hippocampal sclerosis. We focused our study on the 11 patients with cryptogenic temporal lobe epilepsy. Of these, nine had hippocampal sclerosis by pathologic criteria. MR findings included unilateral hippocampal atrophy, an increased signal in the hippocampus on long TR scans, and atrophy in the adjacent white matter and temporal lobe. Hippocampal atrophy was most frequently seen in the red nucleus plane on coronal scans, corresponding to the body of the hippocampus. We also compared hippocampal size on MR with neuronal density in surgical specimens of the 11 patients with cryptogenic temporal lobe epilepsy. A statistically significant correlation was found between MR size and neuronal density in CA3 and CA4 of the cornu ammonis and the granular cell layer of the hippocampus. Since temporal lobectomy eliminated seizures in seven of nine patients with hippocampal sclerosis, preoperative diagnosis by MR has important therapeutic consequences.
Adolescent↗
Regional distribution of MR findings in hippocampal sclerosis.
PURPOSE: To investigate the distribution of MR findings in the hippocampus and amygdala in patients with hippocampal sclerosis. METHODS: We blindly evaluated MR scans for atrophy and signal changes occurring in the amygdala, hippocampal head, hippocampal body, and hippocampal tail in 57 consecutive patients with hippocampal sclerosis proved by pathologic analysis. RESULTS: Regional atrophy or signal change was present in limbic structures. Atrophy was detected in 52 patients, occurring in the amygdala in 7 (12%), hippocampal head in 29 (51%), hippocampal body in 50 (88%), and hippocampal tail in 35 (61%). Hyperintense signal on long-repetition-time images was observed in 49 patients and involved the amygdala in 2 (4%), hippocampal head in 22 (39%), hippocampal body in 46 (81%), and hippocampal tail in 28 (49%). Thirty patients (53%) had abnormal MR findings distributed through the entire ipsilateral hippocampus, 25 (44%) had regional rather than widespread involvement of limbic structures, and 2 (3%) had no MR abnormalities. CONCLUSION: Signal and volume changes associated with hippocampal sclerosis affect the entire hippocampus in most patients. However, a substantial number of patients have MR abnormalities that are regional, involving only portions of the hippocampus and amygdala. The most frequently affected region was the hippocampal body. These findings can have important implications for surgery and quantitative image analysis, if the seizure generator is related to MR changes.
Adult↗
MR findings after depth electrode implantation for medically refractory epilepsy.
PURPOSE: To evaluate using MR imaging chronic changes in the brain parenchyma after electroencephalography depth electrode placement in patients with medically refractory epilepsy. METHODS: A retrospective review of MR scans in 57 patients who underwent stereotactic placement of 210 depth electrodes was performed. Scans were evaluated for evidence of gliosis, hemorrhage, or infection along the probe tracts. RESULTS: Signal abnormalities along the probe tracts were seen in 38 patients (67%). Of the 210 probe tracts evaluated on long-repetition-time images, 85 (41%) were associated with punctate hyperintensity and four (2%) with punctate hypointensity; 120 (57%) showed no MR changes to suggest prior electrode placement. One probe placement was complicated by a significant intraparenchymal hemorrhage. CONCLUSIONS: Depth electrode implantation for electroencephalography monitoring results in imperceptible or minimal chronic changes as detected by MR in almost all patients. The punctate hypersensitivity on long-repetition-time images is though to be caused by gliosis along the probe tracts. These signal changes should not be confused with the seizure focus. Significant hemorrhage or infection is a rare complication of probe placement. Incorporation of MR angiographic data with conventional spin-echo images at the time of stereotactic probe placement may further reduce the low incidence of probe-related hemorrhage.
Adolescent↗
Focal cortical dysplasia of Taylor, balloon cell subtype: MR differentiation from low-grade tumors.
PURPOSE: To test the hypothesis that focal cortical dysplasia of Taylor (FCDT) can be distinguished from low-grade tumors by means of clinical and MR findings. METHODS: We examined 10 clinical and 19 MR imaging variables in patients who underwent surgery for intractable epilepsy over an 8-year period. The 54 patients with low-grade glial neoplasms were compared with the eight patients who had balloon cell FCDT. RESULTS: Statistically significant differences were seen with respect to eight of the MR variables and none of the clinical variables. MR findings suggesting dysplasia rather than tumor included the presence of gray matter thickening associated with a homogeneous hyperintense signal in the subcortical white matter that tapers as it extends to the lateral ventricle. A frontal lobe location favors dysplasia, while a temporal lobe (especially medial temporal lobe) location is more suggestive of a neoplasm. CONCLUSION: Several MR features help distinguish balloon cell FCDT from neoplasms, especially cortical thickening and a tapered signal to the ventricle. This distinction is important for surgical planning, as the decision to operate and the extent of surgical resection often depend on the presence or absence of neoplastic tissue.
Adolescent↗