M Kimura, H Sejima, H Ozasa et al [ Shimane Med Univ Japan]
Technetium – 99m-HMPAO SPECT in Patients with Hemiconvulsions followed by Todd’s Paralysis
Pediatr Radiol 28: 92-9, 1998
Single Photon Emission CT [SPECT] is commonly used to image the brain, there are no reports of the SPECT appearance of the brain after postictal transient focal neurologic trauma. This article describes the SPECT appearance in two patients who had prolonged hemiconvulsion with subsequent transient hemiparesis [ Todd’s paralysis].
SPECT imaging showed that hyperperfusion of the cerebral hemisphere remained many hours after the postictal neurologic deficits resolved, suggesting that the increased cerebral blood flow did not directly impact the hemiparesis.
Prolonged cerebral hyperperfusion was present even though the patient’s seizure was short.
The findings suggest, that in patients with hemiconvulsions and Todd’s paralysis, the prolonged cerebral hyperfusion may be the result of impaired vascular autoregulation and its effects on cerebral function.
Sr MD Devous, RA Thisted, GF Morgan, et al (Univ of Texas, Dallas; Univ of Chicago; Guilford Pharmaceuticals, Baltimore, Md; et al)
SPECT Brain Imaging in Epilepsy: A Meta-analysis
J Nucl Med 39: 285-293, 1998.
Patients failing to respond to medical treatment of partial epileptic seizures originating in the temporal lobe are now treated surgically. Prior to surgery, single photon emission CT (SPECT) is used to assess the patient. Published studies report different sensitivities for SPECT in imaging regional cerebral blood flow on ictal, interictal or postictal scans. This meta analysis (of 624 patients) reviews relevant studies to determine SPECT sensitivities during different stages of seizure.
When SPECT is performed to assist surgery planning for refractory epilepsy, it is important that ictal or postictal images are obtained in conjunction with interictal images. These interictal images are important for comparisons in the evaluation of perfusion changes on the ictal or postictal images.