sodium-pertechnetate-tc-99m and Epilepsies--Partial

The acquisition of multiple radiotracer studies at different time points during a neurological event permits the study of different functional activation states in humans. Peri-ictal SPECT is a promising technique for localizing the epileptogenic zone and would be enhanced by the ability to acquire sequentially coregistered ictal and postictal SPECT images of a single seizure. This study was designed to develop and validate an accurate method for the simultaneous acquisition of 99mTc and 123I SPECT images of the brain.. A multicompartment, transaxial Hoffman brain-slice phantom was filled with 99mTc, 123I or a 3:1 mixture of the two isotopes. Planar and SPECT images were acquired by a dual-head gamma camera system equipped with parallel and fanbeam collimators, respectively. Thirty-two energy windows (2 keV width) were acquired over the energy range 120-184 keV. From the planar data, the signal-to-noise characteristics and crosstalk were measured for each energy window and used to devise an energy window acquisition strategy that was then applied to the SPECT data. Three summed energy windows were created: a primary 99mTc image (130-146 keV), a primary 123I image (152-168 keV) and a secondary 99mTc crosstalk image (134-140 keV). A fraction (0.041) of the 99mTc crosstalk image was subtracted from the 123I image. No crosstalk correction was performed on the primary 99mTc image.. (a) Planar images: results showed 1.3% crosstalk in the 123I image compared with 19.7% for a 10% asymmetric energy window alone. 123I crosstalk into the 99mTc window was 2.79% and was relatively constant with changes in the location of the 99mTc energy window. (b) Tomographic images: results showed 1.51% 99mTc crosstalk in the 123I image compared with 12.44% for the uncorrected image and 3.70% 123I crosstalk in the 99mTc image.. An effective technique for the simultaneous acquisition of 99mTc and 123I radiotracer distributions in the brain has been developed and validated in a phantom model and should have clinical application in peri-ictal functional activation studies of the brain.

Topics: Brain; Epilepsies, Partial; Humans; Image Processing, Computer-Assisted; Iodine Radioisotopes; Phantoms, Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m; Tomography, Emission-Computed, Single-Photon

Clinical, electroencephalographic, rheoencephalographic and linear cerebral circulation findings were compared for 71 epileptics (group 1), 62 migraine patients (group 2) and 6 patients with epilepsy which had developed in the presence of severe migraine with aura (group 3). One-third of migraine patients, mostly of young age, suffering from migraine with aura and basilar migraine had such consciousness disorders as stupefaction and syncopes. EEG changes in migraine patients were considered nonspecific, paroxysmal spike activity arose only in addition of epileptic seizures. Cerebral blood flow measured by radionuclide tracing in migraine-free interval tended to speeding up, while in groups 1 and 3 hemocirculation was slow. Epileptogenic provocation in group 1 patients accelerated cerebral blood flow on the side of the focus, but decelerated it in group 3. The authors hold that the nature of migraine and epilepsy is different. By disintegration of cerebrovascular regulation and vascular supply of the neuron, migraine may promote secondary epileptogenesis.

Topics: Blood Flow Velocity; Cerebrovascular Circulation; Electroencephalography; Epilepsies, Partial; Epilepsy, Generalized; Female; Humans; Male; Migraine Disorders; Pentylenetetrazole; Radionuclide Imaging; Serum Albumin, Radio-Iodinated; Sodium Pertechnetate Tc 99m