Cerebral blood flow in alcohol withdrawal: relation to severity of dependence and cognitive impairment

BACKGROUND

Alcohol dependence affects cerebral function in complex, still unsettled ways.

METHODS

Thirty exclusively alcohol-dependent patients in various stages of withdrawal and 25 matched controls were examined for regional uptake of 99mTc-HMPAO in nine homologous regions of the cerebral cortex by single photon emission tomography (SPET). Image analysis reports regional uptake/uptake in homologous hemisphere.

RESULTS

Alcohol dependence is associated with diminished perfusion in the anterior, and middle frontal regions, and increased perfusion in the posterior temporal regions. Frontal hypoperfusion is related to alcohol withdrawal because it disappears with longer time between imaging, last intake and correlates with a composite index of cognitive impairment at the time. Temporal hyperperfusion persists for longer periods. Severe dependence correlates with both frontal, and temporal altered perfusion.

DISCUSSION

Alcohol withdrawal leads to redistribution of blood flow favouring the temporal, and more posterior regions of the cortex at the expense of frontal flow.

Single photon emission tomography with 99m Tc-HMPAO in Arab patients with depression

BACKGROUND

This study investigates the rate of cerebral blood flow (rCBF) in Arab patients wth depression.

METHODS

Forty-four patients with DSM-III-R major depressive disorders were studied at rest using single photon emission computerized tomography (SPECT) with 99m Tc-HMPAO in comparison with 20 normal controls. All patients were assessed using the Hamilton Rating Scale for Depression (HRSD).

RESULTS

The depressed group showed greater rCBF in left and right posterior frontal and parietal cortical regions than normal controls. Within the depressed group, patients with the least severe illness (HRSD < 20) had significantly lower rCBF than normal controls, whilst those with moderately severe (HRSD 20-29) and severe (HRSD > 30) had significantly greater rCBF in most cortical regions than normal controls. Symptom scores, derived from the HRSD were predicted by rCBF principally increased rCBF in the left frontal cortex.

CONCLUSIONS

These results suggest a generalized cerebral activation principally in the frontal cortex which is in contrast to the results of most previous studies but more in line with the results of studies of induced affect and some studies of depression subsyndromes.

Cortical hypoperfusion in symptomatic West syndrome. A SPECT study

Diffuse and focal changes in glucose utilization and abnormal cerebral cortical perfusion were found in West syndrome by PET and SPECT investigations. In this study 99mTc-HMPAO SPECT was performed on seven patients with symptomatic West syndrome several months after the onset of the spasms. Regions of interest of the cerebral cortex and cerebellum were delineated by an automated computer program and cortical/cerebellar ratios of the HMPAO uptake in the patients were compared to those of controls. The basal ganglia/cerebellar ratios were compared after manual placement of regions of interest. Significantly reduced perfusion was found in the bilateral anterior, mid frontal and perisylvian cortex, and in the left posterior frontal and temporal areas. Well localized, focal changes in the cortical perfusion were not found and the perfusion in the basal ganglia proved to be normal. These abnormalities in the cortical perfusion may reflect a pre-existing brain pathology together with an encephalopathy due to the hypsarrhythmia and infantile spasms.

Agyria-pachygyria: cerebral perfusion studies by 99mTc-HMPAO SPECT [corrected]

Cerebral perfusion was investigated in three patients with agyria-pachygyria by using 99mTc-HMPAO SPECT in order to study the distribution of blood flow. Diffuse cortical hypoperfusion was found in all three infants. The visual cortex was not identifiable in two of the cases. The basal ganglia and cerebellum were prominent by their normal high activity, while tracer uptake was very low in the thalamus. The possible role of improper development of interneuronal connections and abnormal vascular pattern in background of the perfusion defect is discussed.

Regional cerebral blood perfusion in children with hemiplegia: A SPECT study

Fourteen children with spastic hemiplegia of various etiology: cerebral palsy (seven cases, five with porencephalic cyst); stroke with small deep infarcts (two); hemiconvulsion-hemiplegia-epilepsy syndrome (three); traumatic brain injury (two), were investigated by 99mTc-HMPAO SPECT. Localized and remote perfusion abnormalities were studied. Hypoperfusion corresponding to CT abnormalities was found in each group, but the perfusion deficit extended beyond the boundaries of anatomical defects, most prominently in cases with widespread unilateral epileptic discharges. Ipsilateral cerebellar diaschisis was observed in patients with early cerebral insult (who had porencephalic cyst of pre- or perinatal onset) and crossed cerebellar diaschisis was noted in a patient who sustained traumatic brain injury at a later age. Diaschisis in the overlying cortex, thalamus and basal ganglia was noticed in several cases. Although clinical symptoms or signs could not be unequivocally attributed either to the size of the perfusion defects beyond the boundaries of lesions shown by CT or to the diaschisis, the findings may contribute to reveal age-related abnormal perfusion patterns.

Kidney volume estimation using 99Tcm-DMSA RSPECT: evaluation by phantom study

Renal parenchymal volume is important for clinical interpretation. The phantom study was carried out to validate the volume calculation. The volume of kidney phantom was determined using reoriented single photon emission computed tomography (RSPECT). The phantom volume range was 20-300 ml. There are two major factors in the determination of volume which are radioactivity concentration and organ/background ratio. Our results showed that the effect of radioactivity concentration on the volume in the kidney phantom is -3.3 to 7.5% whereas the effect of organ/background ration was only 2.2%. Our relative volume deviation, therefore, from the real volume was 1.43%. We concluded that it is feasible to use kidney volume in clinical work.

Comparison of planar and SPECT 99Tcm-dimercaptosuccinic acid scintigraphy in calculating differential kidney function

An extensive study to compare planar and single photon emission computed tomographic (SPECT) 99Tcm-dimercaptosuccinic acid (DMSA) determination of differential kidney function (DKF) has been carried out. The study has demonstrated that it is possible to use SPECT differential kidney function in place of that obtained using planar scintigraphy. The SPECT DKF value correlated with the planar DKF value. Gradient shaded three-dimensional surface images, reoriented transaxial, sagittal and coronal slices were produced during the same processing method.