Elmer C. San Pedro

Regional Cerebral Blood Flow and Magnetic Resonance Spectroscopic Imaging Findings in Diaschisis From Stroke

Background and Purpose— This study evaluated blood flow and metabolite changes in cerebral diaschisis from internal capsule region infarction using regional cerebral blood flow (rCBF) single-photon emission computed tomography (SPECT) and 1H magnetic resonance spectroscopic imaging (MRSI). We hypothesized that complementary measures of diaschisis effects in white matter (characterized by 1H MRSI) and gray matter (characterized by changes in rCBF) can be measured and exhibit parallel changes. Methods— Five stroke patients and 16 normal controls underwent Tc-99m hexamethylpropyleneamine-oxime brain SPECT and 1H MRSI at 4.1 T. The metabolites N-acetyl aspartate (NAA) and creatine (Cr) were measured using 1H MRSI. The tissue content was expressed as the percent of gray or white matter in each MRSI voxel to allow comparison of the differential effects of diaschisis in gray and white matter tissue types. The blood flow and metabolite changes were evaluated at superior cerebral regions distant from the stroke to allow a measure of diaschisis relatively unconfounded by their expected changes in the infarction region. Results— The rCBF SPECT data in stroke patients showed a perfusion defect, with size ranging from 1.23 cc to 10.23 cc, in the region of cortical diaschisis. 1H MRSI showed increased Cr/NAA ratios in regions of white matter diaschisis. There was a tendency for larger rCBF defect size to be associated with greater increases in Cr/NAA values in the same diaschitic cerebral hemisphere, ipsilateral to the infarction. Conclusion— Diaschisis ipsilateral to stroke in white matter can be characterized by 1H MRSI, and diaschisis ipsilateral to stroke in cortical gray matter regions can be characterized by changes in rCBF. The tendency for greater reductions in cortical rCBF values to be associated with increased Cr/NAA values in the same diaschitic cerebral hemisphere implies that a relationship exists between rCBF reductions in gray matter and abnormal changes in white matter subservient to it.

Anterior Cingulate Gyrus Epilepsy: The Role of Ictal rCBF SPECT in Seizure Localization

Summary: Purpose: The goal of this report is to demonstrate the utility of ictal brain single photon emission tomography (SPECT) in a 39‐year‐old man with complex partial seizures arising from the anterior cingulate gyrus. Seizures originating from the anterior cingulate gyrus are difficult to localize because they have variable ictal semiology, are usually brief, and have rapid cortical propagation.

Basis and Clinical Application of Brain Imaging

18.2 Radiopharmaceuticals 452 18.2.1 Tc-99m-Hexamethylpropylene Amine Oxime 452 18.2.2 Tc-99m-Ethyl Cysteinate Dimer 452 18.2.3 Xe-133 for Quantitative Regional Cerebral Blood Flow 454 18.2.4 O-15H2O forQuantitative Regional Cerebral Perfusion Measured by PET 455 18.2.5 Thallium-201 455 18.2.6 Tc-99m-Hexakis-2-methoxy-2-isobutyl Isonitrile 457 18.2.7 2-[F-18]Fluoro-2-deoxy-d-glucose 457 18.2.8 Dopamine Transporter Receptor Binding Agents 458 18.2.9 Cell Proliferation ImagingUsing [F-18]Fluoro-3’-deoxy-3’-l-fluorothymidine PET 460