F Viñuela

Computed tomography in temporal lobe epilepsy

Forty patients who had intractable temporal lobe epilepsy had surgery for treatment of their seizures following study by computed tomography (CT). Fifteen of 19 patients with tumors had good correlation between CT and pathological findings. Another group of patients had macroscopic changes that were demonstrated on CT and verified at surgery. Sixteen patients had microscopic pathological diagnoses including cytoarchitectural abnormalities, Chaslin gliosis, and ectopic neurons. Six of these had enlarged temporal horns on the ipsilateral and five on the contralateral side to the electroencephalographic-pathological abnormality. In the investigation of temporal lobe epilepsy we believe that CT, especially with the newer generation scanners, records tumors and other larger macroscopic changes but that temporal horn size is unreliable in predicting the abnormal side if only microscopic changes are present. Index Terms: Epilepsy—Brain, abnormalities—Computed tomography.

Revisited old and new ct findings in unruptured larger arteriovenous malformations of the brain

Several papers have already described the computed tomographic (CT) findings in arteriovenous malformations (AVMs) of the brain. In a population of larger and unruptured AVMs, however, improved resolution CT has made it possible to demonstrate findings not previously appreciated: (a) major and minor mass effects in the absence of rupture of an AVM (33 of 60 cases); (b) cisternal enlargement secondary to vessel ectasia and tortuosity; (c) extensive edema of white matter; (d) the detailed features of finer and coarser calcifications of the malformation; (e) gray matter changes, disturbances in the gray-white matter interface, and intrinsic hypodense regions within the AVM; and (f) visualization of small vessels on intravenous enhancement.

Technical Advances in Endovascular Therapy of Brain Arteriovenous Malformations

Endovascular therapy of intracranial vascular diseases—arteriovenous malformations (AVMs), aneurysms, fistulas, tumors—is a natural extension of techniques of cerebral angiography. The development of microcatheters with or without calibrated leak balloons in their tips allows safe navigation beyond the circle of Willis and catheterization of cortical or deep-seated arteries of the brain.1 it is also possible to use the intracranial venous route and reach the venous sinuses or even the vein of Galen using a transfemoral technique. The latter technique is applied for embolization of AVMs involving the dural sinuses (especially transverse and cavernous sinuses2) or vein of Galen aneurysms in neonates.3 Various microcatheters are now available that allow safe navigation beyond the circle of Willis if used judiciously. We have catheterized 850 arterial feeders in 228 brain AVMs (Fig. 19.1). No technical or clinical complications were observed in the last 347 superselec-tive catheterizations of brain cortical or deep AVM feeders larger than 2 mm in diameter. Superselective angiography and Amytal testing of arterial feeders of AVMs located in eloquent areas of the brain may be performed on an outpatient basis. This superselective morphological and functional assessment of an AVM provides important information not available with standard cerebral angiography. For brain AVMs that appear to involve the motor cortex, this anatomical and functional localization is compared to localization techniques using somatosensory evoked potentials and intraoperative electrocorticography in an awake patient.4 The preliminary use of magnetoencephalography to localize the speech cortex has shown some potential, and it appears to be more useful for preoperative localization of the Wernicke area.5