Neuroradiologic applications of central nervous system SPECT

Single photon emission computed tomography (SPECT) of the central nervous system (CNS) has many potentially useful interventional neuroradiologic applications. CNS SPECT allows easy and safe evaluation of the collateral circulation during internal carotid balloon test occlusion. The cerebrovascular distribution of intracarotid amobarbital sodium, which is used in the Wada test, can be accurately determined with simultaneous injection of a radiopharmaceutical. Easy and safe evaluation of the extent and distribution of vasospasm associated with subarachnoid hemorrhage or cerebral angiography is also possible with CNS SPECT. Images obtained after administration of acetazolamide can be compared with baseline images to evaluate cerebrovascular reserve before carotid endarterectomy. Seizure foci can be identified if peripheral intravenous injection is performed during an ictus. Thallium-201 imaging can be used to direct stereotactic brain biopsy to check for tumor recurrence. Radiologists need to familiarize themselves and their clinical colleagues with the many uses of this imaging technique.

Stereotactic location and excision of seizure focus with xenon-enhanced CT

A case of intractable seizures, originating in the motor cortex, was successfully treated with excision of the seizure focus after precise location of the focus on depth electrode recordings. The depth electrode was placed stereotactically with coordinates from xenon-enhanced CT images. Prior attempts at treating the seizures with ablation of seizure foci had resulted in disappearance of seizure activity on electrocorticography study without cessation of clinical seizures.

Demyelinating disease after neurologically complicated primary Epstein-Barr virus infection

This report describes five patients who, following a neurologically complicated primary Epstein-Barr virus infection, developed progressive or relapsing neurologic deficits. The sequelae in four patients followed 4 to 12 years led to the diagnosis of multiple sclerosis (MS). The fifth patient presented with acute disseminated sclerosis and exhibits diffuse neurologic deficits that have persisted for 2 years. We suggest that the diagnosis of an unexplained acute neurologic or psychiatric syndrome should raise the question of a primary EBV etiology. A precisely timed serologic and hematologic study of the blood is imperative to capture the essential evidence. The data presented represent a clinical association between a neurologically complicated primary EBV infection and both chronic and acute demyelinating disease. The evidence does not justify a conclusion that EBV virus causes MS.

King's syndrome with malignant hyperthermia. Potential outpatient risks

King's syndrome is a sporadic genetic syndrome exhibiting characteristic facial features, short stature, and subclinical myopathy. Affected individuals are susceptible to malignant hyperthermia (MH) induced by anesthesia, stress, or trauma. The incidence of King's syndrome is uncertain as all reported cases were first recognized following an episode of MH. We report a case of King's syndrome without the cryptorchidism and pectus carinatum associated with the syndrome. King's syndrome's possible link to Noonan's syndrome is discussed herein, and the diagnosis and management of MH are briefly reviewed. We recommend evaluation for MH susceptibility in all patients with clinical signs consistent with King's syndrome and in their family members prior to anesthesia.

Neurological and neuropsychological effects of cerebral spinal fluid shunting in children with assumed arrested ("normal pressure") hydrocephalus

Normocephalic children found to have ventriculomegaly during evaluation of long-standing (4.5-8.5 years) neurological disorder were tested for academic achievement, intellectual quotient and neuropsychological functioning. Radioactive iodinated serum cisternography, pre and post-shunt electrophysiological studies (visual evoked responses, brainstem auditory evoked potentials, sleep electroencephalograms) and radiological studies (skull radiographs computed tomography) were recorded. Four children who have been followed more than one year after insertion of ventricular-peritoneal shunts are presented. All demonstrated improvement in psychometric findings along with some improvement in CT scan and EEG studies. The most marked initial changes were noted on measures of neuropsychological performance, accompanied later by improvement in measures of intelligence. Achievement test scores showed no consistent pattern of change. This sample suggests that there is a group of asymptomatic children with apparent clinically stable (arrested) hydrocephalus in whom abnormal neuropsychological testing indicates the need for cerebrospinal fluid shunting, with subsequent improvement.

Pseudotumor cerebri following treatment of hypothalamic and primary hypothyroidism

Pseudotumor cerebri occurs in many diverse endocrine and nonendocrine disorders. We report what we believe is a new association following initiation of thyroxine (T4) replacement in hypothalamic hypothyroidism, as well as another occurrence following T4 replacement in primary hypothyroidism. The less than benign clinical course reported in these two patients suggests the need for careful neurologic and funduscopic evaluation during the initial months of T4 replacement in all cases of hypothyroidism.

CT measurements of cranial growth: microcephaly

Computed tomographic (CT) head scans were measured to determine the cranial dimensions of four children with microcephaly. These measurements were compared with cranial dimensions of normal children. CT proved to be useful in determining the developmental status of children with neurologic problems relative to their normal counterparts on the basis of cranial dimensions.

Abnormal brainstem auditory evoked potentials and neuropathology in "locked-in" syndrome

Brainstem auditory evoked potentials (BAEPs) were studied in a "locked-in" syndrome resulting from multiple occlusions of paramedian pontine arteries. Abnormality of BAEPs (first recorded 10 days after infarction) indicated that brainstem damage extended beyond the basis pontis, where, typically, interruption of corticospinal pathways results in the "locked-in" syndrome. Later, partial BAEP recovery suggested that the technique can be used to distinguish between permanent and transient brainstem involvement. Autopsy examination revealed close correspondence between permanent brainstem damage and persistent BAEP abnormalities. Persistent abnormal prolongation of III-V conduction time and aberration of wave IV were associated with damage near the lateral lemniscus contralateral to the stimulated ear.