✓ Transient neuroimaging abnormalities associated with seizure activity have received little attention in the literature. The authors report a focal magnetic resonance (MR) imaging abnormality of the corpus callosum in a patient following a secondary generalized seizure. A 27-year-old right-handed man presented with a history of medically refractory partial seizures since the age of 1 year. The results of an MR imaging study obtained 4 months prior to the patient undergoing video-electroencephalography monitoring were unremarkable. After the patient discontinued all antiepileptic medications, a secondary generalized seizure of right temporal origin was recorded. Five days later, repeated MR imaging revealed a nonenhancing 14 × 11—mm ovoid hyperintense lesion in the splenium of corpus callosum. The patient was asymptomatic, and his neurological and neurocognitive examinations remained unremarkable. Follow-up MR imaging 5 weeks and 1 year later demonstrated near-complete resolution of the lesion. Benign and transient abnormalities in the splenium can occur as a periictal phenomenon. A high index of suspicion and follow-up imaging may prevent further unwarranted intervention.
Transient postictal magnetic resonance imaging abnormality of the corpus callosum in a patient with epilepsy
Case report and review of the literature
Aaron A. Cohen-Gadol, Jeffrey W. Britton, Clifford R. Jack Jr., Jonathan A. Friedman and W. Richard Marsh
Francis H. Tomlinson, Paul J. Kurtin, Vera J. Suman, Bernd W. Scheithauer, Judith R. O'Fallon, Patrick J. Kelly, Clifford R. Jack Jr. and Brian P. O'Neill
✓ The authors report on a clinicopathological study of 89 surgical patients with histologically proven primary parenchymal brain lymphoma, all diagnosed between January 1975 and December 1990. The cohort included 60 men and 29 women whose median age at diagnosis was 60 years (range 14 to 84 years). The duration of symptoms was less than 8 weeks in 48% of the patients. Symptom groups included focal neurological deficit (73%), neuropsychiatric symptoms (28%), seizures (9%), and increased intracranial pressure (3%). A total of 132 tumors were seen in 89 patients: the most common sites were frontal (32 patients), temporoparietal (31 patients), and basal ganglia (17 patients); multiple lesions were reported in 23 patients. No patient had antecedent of human immunodeficiency virus positivity or acquired immunodeficiency syndrome. A family history of cancer was present in 33% of the patients, three-quarters of whom were first-degree relatives. Histological subtypes (National Cancer Institute Working Formulation) included 64 large cell (72%) and 13 immunoblastic (15%) tumors. Phenotype was determined in 66 patients: 63 were B-cell type and three were T-cell type. Surgical resection was performed in 47% of the cases, with the remainder undergoing biopsy only. All but six patients received radiation therapy. Thirty-one patients received chemotherapy, whereas 46 patients did not; data on the remaining 12 patients were unavailable. The end point of the study was death from any cause. At the time of last contact, 69 of the patients (78%) had died; the median survival time for this study group was 20.9 months. On univariate analysis, prognostic factors significantly associated with survival included age at diagnosis, family history of cancer, and focal neurological deficit. Multivariate analysis revealed four unfavorable prognostic factors: age greater than or equal to 60 years, history of cancer in first-degree relatives, focal deficit, and ependymal contact. After adjustment for these variables, clinical syndrome, size and number of lesions, extent of surgery, histological cell type, radiation dose, and use of chemotherapy were not significantly associated with survival.
Frank H. Tomlinson, Clifford R. Jack Jr. and Patrick J. Kelly
✓ Serial postoperative magnetic resonance (MR) studies were obtained in 21 patients who underwent somatotopically placed stereotactic radiofrequency (rf) ventralis lateralis thalamotomy for the control of movement disorders. The MR studies were reviewed to determine the MR characteristics of early-phase (≤ 7 days) and late-phase (8 days to 5 months) lesions. Surgery was performed for the control of parkinsonian tremor (14 cases), intention tremor (six cases), and essential tremor (one case). Single rf lesions were made with an electrode (1.6 mm in diameter, 3 mm in tip length) heated to 78°C for 60 seconds. On MR images of the lesions, three distinct concentric zones were identified, described as follows (from the center outward). Zone 1 gives increased signal on long-relaxation time (TR) (T2-weighted) MR images in early- and late-phase lesions and decreased signal on short-TR (T1-weighted) MR images in early-phase lesions only. Zone 2 gives decreased signal on long-TR (T2-weighted) images in early- and late-phase lesions; it gives isointense signal on short-TR (T1-weighted) images in early-phase lesions only. Zone 3 gives increased signal on long-TR (T2-weighted) images in early-phase lesions only and decreased signal on short-TR (T1-weighted) MR images in early-phase lesions only. It is considered that in early-phase lesions, Zone 2, with a mean diameter of 7.3 mm on axial long-TR (T2-weighted) imaging, represents an area of hemorrhagic coagulation necrosis. In late-phase lesions, Zone 2, with a mean diameter of 5.0 mm on axial long-TR (T2-weighted) imaging, represents hemosiderin deposition. Zone 3 likely represents edema, and this zone disappears between the early and late periods.
From regression analysis, lesion size began to stabilize at approximately 7 months with a mature lesion diameter of 3.3 mm. Long-term follow-up monitoring (median 16 months) showed good tremor control. Based on clinical and radiological findings, the authors conclude that forms of hemoglobin are suitable markers to assess the size of rf lesions. Serial MR imaging provides a noninvasive means of studying the evolution of rf thalamotomy lesions.
Clifford R. Jack Jr., Emre Kokmen and Burton M. Onofrio
✓ The case of a 30-year-old woman with Chiari I malformation and a cervicothoracic syrinx is presented. The patient was followed clinically over a 2½-year period. Spontaneous and complete resolution of the syrinx, as documented by serial magnetic resonance studies, was accompanied by only a minimal change in objective symptomatology.
Clifford R. Jack Jr., Thoralf M. Sundt Jr., Nicolee C. Fode and Dale G. Gehring
✓ Between 1974 and 1982, an anastomosis between a pedicle of the superficial temporal artery (STA) and a cortical branch of the middle cerebral artery (MCA) was performed in 163 carotid systems in 157 patients for internal carotid artery occlusion in whom postoperative angiograms were available for analysis. The angiographic opacification of the arterial system was correlated with the patient's preoperative neurological function and stroke in the follow-up period.
From this analysis, the following observations were made: 1) 96% of bypasses were patent; 2) 80% of bypasses achieved a high or medium MCA filling score; 3) there was hypertrophy of the STA in 70% of the cases; 4) greater bypass filling occurred in hemispheres with nonvisualized preoperative collateral circulation than in those with readily visualized collateral flow; 5) a meaningful correlation between angiographically assessed postoperative bypass function and stroke rate was not possible because only four patients suffered an ipsilateral hemispheric stroke in the 8-year follow-up period; and 6) patients who were neurologically unstable before the procedure were at greatest risk for a stroke in the follow-up period. It is apparent that objective analysis of the effectiveness of an STA-MCA bypass, or any other form of extracranial bypass, must await the development of new diagnostic studies in which high-resolution three-dimensional quantification of cerebral blood flow is possible. These studies will necessarily be correlated with preoperative and follow-up clinical data.