technetium-tc-99m-exametazime and AIDS-Dementia-Complex

We prospectively studied a cohort of 25 HIV-1 infected individuals with no clinical signs of encephalopathy with 99mTc-HMPAO-SPECT. The findings were correlated with magnetic resonance imaging (MRI), neuropsychological testing and clinical staging aiming at the early diagnosis of HIV encephalopathy by single photon emission computed tomography (SPECT). A total of 25 matched seronegative controls were subject to neuropsychological testing only. A total of 24 patients and controls were monitored for 6-46 months (mean and median 26 months). No patients developed AIDS dementia complex during the study; 3 patients developed minimal symptoms (MSK classification stage 0.5). There was a significant decline in 99mTc-HMPAO uptake over time and neuropsychological abnormalities progressed. Unexpectedly, there was a correlation of high cortical and subcortical 99mTc-HMPAO uptake and low performance in cognitive dysfunction tests, indicating a possible inflammatory reaction in the brain with increased blood flow due to HIV infection. We conclude that, in non-demented HIV-infected individuals, both the 99mTc-HMPAO uptake and functional level slowly decrease over time, but the regional cerebral blood flow decrease could be masked by a direct HIV-induced inflammatory reaction in the brain, which gives a 99mTc-HMPAO hyperfixation.

Topics: Adult; AIDS Dementia Complex; Cognition Disorders; Cohort Studies; Female; HIV Infections; Humans; Longitudinal Studies; Magnetic Resonance Imaging; Male; Middle Aged; Neuropsychological Tests; Prospective Studies; Radiopharmaceuticals; Sensitivity and Specificity; Severity of Illness Index; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

AIDS dementia complex is a well-defined neurological manifestation of the HIV infection. Its anatomo-pathological pattern is cerebral atrophy, grey and white matter abnormalities and vascular changes, and the main symptom is progressive dementia. SPECT with Tc 99m HMPAO has proved to be an useful tool in studying Alzheimer and multi-infarct dementia, and its use has been recently proposed in AIDS-dementia. We studied with Tc 99m HMPAO 57 Pts (11 HIV+, 26 ARC, 17 AIDS) and control group of 7 drug-addicted seronegative Pts. We found positive results in 45% SPECT, 18% CT, 0% neurological tests of dementia in HIV+ phase, versus 52%, 41, 20% in ARC phase and 94%, 88% and 76% in AIDS phase, while all control Pts were negative. Control group is too small to exclude with all possibility of doubt cerebral blood flow impairment caused by drug damage but nevertheless we think that SPECT examination with 99 mTc HMPAO has an important role in assessing CBF changes in earlier stages of AIDS disease. These changes are probably forerunners of definitive cerebral damage and may be important markers of the advancement of disease.

Topics: Adult; AIDS Dementia Complex; Brain; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) is a common effect of the AIDS virus. We studied the regional cerebral blood flow of patients with early ADC and its response to atevirdine mesylate.. Ten men with early ADC, who had failed or were intolerant to zidovudine or didanosine therapy, were treated with atevirdine mesylate for 12 wk. Cerebral perfusion SPECT using 99mTc-HMPAO was performed at Week 0 and Week 12. SPECT images were analyzed qualitatively and semiquantitatively.. The cerebral perfusion abnormalities in early ADC were usually mild and characteristically involved the cortices and periventricular regions bilaterally and symmetrically. Four patients were able to complete the protocol. Three of these patients responded to atevirdine clinically, two of whom showed improvement in their Week 12 SPECT images. The other responder had an essentially unchanged image. The patient who did not respond to atevirdine showed a definite deterioration in cerebral perfusion.. Cerebral perfusion SPECT is useful in detecting and assessing therapeutic responses in ADC. The preliminary results of atevirdine in treating ADC are promising and need further investigation.

Topics: Adult; AIDS Dementia Complex; Anti-HIV Agents; Brain; Cerebrovascular Circulation; Humans; Male; Middle Aged; Pilot Projects; Piperazines; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Although specific patterns of technetium-99m exametazime [99mTc-hexamethylpropylene amine oxime (HMPAO)] brain single-photon emission tomography (SPET) uptake have been described for patients with dementia, no multi-institutional study has evaluated interobserver agreement. Interobserver agreement for 99mTc-HMPAO brain SPET uptake patterns in 50 clinically diagnosed demented subjects from four institutions were studied. Neurologists classified these subjects as presumed Alzheimer's disease (n = 21), confirmed Alzheimer's disease (n = 10), multi-infarct dementia (n = 9), HIV-related dementia (n = 7), or "mixed" (n = 3). In addition 20 normal (five per institution) 99mTc-HMPAO studies were included in a randomized blinded evaluation by three readers each from a different institution. Readers classified the general appearance of the images in one of four categories: normal, globally decreased uptake, focal areas of decreased uptake, and patchy changes in uptake. Consensus results show a sensitivity of 72% and specificity of 79% for identifying abnormalities in scans of demented subjects. Readers also rated 99mTc-HMPAO uptake in eight designated regions in each hemisphere. Significant reader agreement (P < 0.01) for the classification by general appearance and the ratings of regional uptake was obtained. This study demonstrates that interpretation of regional cerebral blood flow/SPET images is concordant across multiple institutions and readers.

Topics: AIDS Dementia Complex; Alzheimer Disease; Brain; Dementia, Multi-Infarct; Humans; Observer Variation; Organotechnetium Compounds; Oximes; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The objective of this study was to characterize the cognitive status of a population of asymptomatic HIV-positive drug addicts (patient group) to document the relationship between neuropsychological results and cerebral blood flow defects as measured by single photon emission computed tomography. As a control group we employed an age-matched population of HIV-seronegative drug addicts. Some neuropsychological differences were found between patients and controls and between drug addicts and normal population. We could not detect any difference in cerebral blood flow rates among HIV-1-positive and -negative drug addicts.

Topics: AIDS Dementia Complex; Brain; Cerebral Cortex; Diagnosis, Differential; Dominance, Cerebral; HIV Seronegativity; HIV Seropositivity; HIV-1; Humans; Neuropsychological Tests; Organotechnetium Compounds; Oximes; Regional Blood Flow; Substance Abuse, Intravenous; Substance-Related Disorders; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Chronic fatigue syndrome is an illness of unknown origin that begins abruptly with a flulike state and has symptoms suggesting both a chronic viral encephalitis and an affective disorder. We compared single-photon emission computed tomography (SPECT) scans of patients with chronic fatigue syndrome with those of patients with AIDS dementia complex and unipolar depression.. We used 99mTc-hexamethylpropyleneamine oxime to examine 45 patients with chronic fatigue syndrome, 27 patients with AIDS dementia complex, and 14 patients with major unipolar depression. Scans of 38 healthy persons were used as controls. Comparison of regional defects between groups, as well as midcerebral uptake indexes (an objective measure of global radionuclide uptake), was performed by using analysis of variance with the Student-Newman-Keuls option. Correlation between the number of regional defects and the midcerebral uptake index was determined by using the Spearman rank-correlation test.. Patients with AIDS dementia complex had the largest number of defects (9.15 per patient) and healthy patients had the fewest defects (1.66 per patient). Patients with chronic fatigue syndrome and depression had similar numbers of defects per patient (6.53 and 6.43, respectively). In all groups, defects were located predominantly in the frontal and temporal lobes. The midcerebral uptake index was found to be significantly lower (p < .002) in the patients with chronic fatigue syndrome (.667) and patients with AIDS dementia complex (.650) than in patients with major depression (.731) or healthy control subjects (.716). Also, a significant negative correlation was found between the number of defects and midcerebral uptake index in patients with chronic fatigue syndrome and AIDS dementia complex, but not in depressed patients or control subjects.. These findings are consistent with the hypothesis that chronic fatigue syndrome may be due to a chronic viral encephalitis; clinical similarities between chronic fatigue syndrome and depression may be due to a similar distribution and number of defects in the two disorders.

Topics: Adult; Aged; AIDS Dementia Complex; Brain; Depressive Disorder; Fatigue Syndrome, Chronic; Female; Humans; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Single photon emission computed tomography (SPECT) using N-isopropyl-p-(123I)iodoamphetamine (123I-IMP) and 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) was performed in 25 patients with different clinical stages of AIDS encephalopathy. The average interval between the two examinations was 7 days. In 15 of the 25 cases (60%) 99Tcm-HMPAO scans were different from 123I-IMP scans. Uptake defects of different extent were observed in 8 of 25 cases (32%), of different extent and different location in 3 of 25 cases (12%) and of identical extent but of different location in 4 of 25 cases (16%). Differences in the uptake patterns of 123I-IMP and 99Tcm-HMPAO with regard to extent and/or location were more commonly shown in patients with early acquired immunodeficiency syndrome (AIDS) encephalopathy (P = 0.0372). In this group, 99Tcm-HMPAO showed uptake defects of greater extent more frequently than did 123I-IMP (P = 0.0156). Our data indicate different brain uptake mechanisms of 123I-IMP and 99Tcm-HMPAO in early and advanced AIDS encephalopathy.

Topics: Adult; AIDS Dementia Complex; Amphetamines; Brain; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Intravenous drug use is a major risk factor for HIV-1 infection. Since both AIDS dementia complex (ADC) and cocaine have been associated with abnormal brain perfusion imaging, we compared the scintigraphic patterns of ADC patients and cocaine polydrug users with normal control subjects using 99mTc-HMPAO SPECT. We found a high incidence of cortical defects in both ADC (100%) and cocaine-dependent (90%) subjects. In the cocaine and ADC patients, cortical defects were most frequent in the frontal, temporal and parietal lobes and occurred with similar frequency in the two populations. In both groups, the number of cortical defects per subject was higher than normal subjects (10.0 +/- 5.0 for ADC, 10.1 +/- 5.2 for cocaine and 0.7 +/- 1.5 for normal), background activity was high (a 65% and 60% incidence for ADC and cocaine, respectively), and basal ganglia involvement was frequent (40% and 65% for ADC and cocaine). We conclude that the brain perfusion pattern, while a sensitive indicator of ADC, cannot be distinguished from chronic cocaine polydrug use and caution should therefore be applied before entertaining a specific diagnosis.

Topics: Adult; AIDS Dementia Complex; Brain; Cocaine; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Substance-Related Disorders; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Alzheimer's disease produces regional abnormalities in brain blood flow and metabolism that may result in recognizable scintigraphic patterns. We determined the predictive value of 99mTc-HMPAO SPECT for the presence of Alzheimer's disease based on a prospective study of 132 consecutive patients coming to our nuclear medicine clinical unit for evaluation of their memory loss or cognitive abnormalities. During clinical follow-up averaging 10.1 mo, a final diagnosis was established in 113 patients, 52 of which had Alzheimer's disease. The probability of Alzheimer's disease was determined for seven scintigraphic patterns. The probability was 19% that patients with memory loss and normal perfusion had Alzheimer's disease. For abnormal perfusion patterns, the probability of Alzheimer's disease was 82% with bilateral temporoparietal defects, 77% with bilateral temporoparietal defects with additional defects, 57% with unilateral temporoparietal defects, 43% with frontal defects only, 18% with other large defects and 0% with multiple small cortical defects. We conclude that for 99mTc-HMPAO SPECT the predictive value of bilateral temporoparietal defects for Alzheimer's disease is high, while the perfusion patterns of unilateral temporoparietal perfusion defects and frontal defects only, which occur in 20% of patients with Alzheimer's disease, are not predictive of that disease.

Topics: AIDS Dementia Complex; Alzheimer Disease; Cerebrovascular Circulation; Dementia, Vascular; Diagnosis, Differential; Humans; Organotechnetium Compounds; Oximes; Parkinson Disease; Predictive Value of Tests; Probability; Prospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: AIDS Dementia Complex; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Human immunodeficiency virus (HIV) infection is frequently complicated by a variety of disease processes affecting the central nervous system (CNS). One of them is AIDS dementia complex (ADC), which, in the absence of opportunistic infection, is believed to be caused by HIV itself. ADC is characterized by a constellation of cognitive, motor, and behavioral symptoms that progressively get worse. This study was coined to recruit AIDS patients without any opportunistic CNS infection but with signs of CNS abnormality as evidenced by behavioral and subtle motor changes, then to categorize them into five stages, and finally to perform the cerebral blood flow scan using Ceretec. The aim of this study was to correlate the abnormalities of the brain scan with the different stages of ADC. Five patients were analyzed, with dementias ranging from mild to severe according to Price's classification. After confirming the absence of CNS opportunistic infections and AIDS associated malignancies by CT of the brain, the patients underwent psychiatric evaluation and brain scans. The SPECT scans were very sensitive in showing uptake defects in the brain, even in the early stages of ADC. The blood flow defects were more pronounced in the later stages, while the CT scans remained negative except in patients with the most severe dementia.

Topics: Adult; AIDS Dementia Complex; Brain; Cerebrovascular Circulation; Humans; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

In forty patients at early and advanced stages of HIV infection (Walter Reed stages I-IV) regional cerebral blood flow was determined by 99mTc-HMPAO SPECT, comparing the results with CT and MRI findings. All patients with HIV encephalopathy (AIDS dementia complex) had pathologic SPECT results (multilocular, patchy uptake defects), but also in earlier and even earliest stages of HIV infection positive SPECT findings were observed. Compared to functional SPECT imaging, morphologically orientated methods (CT, MRI) were insensitive in detecting HIV-induced foci: more than 50% of the patients with pathologic SPECT findings had negative CT or MRI scans. Most patients in advanced Walter Reed stages had neurological abnormalities accompanied by positive SPECT. Subtle alterations of HMPAO uptake were observed even in a few cases of early HIV infection without neurological CNS symptoms. The data presented suggest that HMPAO SPECT is highly sensitive in the detection of altered brain perfusion not only in advanced but also early stages of HIV infection. Changes in regional cerebral blood flow are present before noticeable structural defects may be observed. Thus, it is suggested to use HMPAO SPECT in the evaluation and monitoring of patients with, and particularly at risk for, HIV encephalopathy.

Topics: Adult; Aged; AIDS Dementia Complex; Brain; Cerebrovascular Circulation; Female; HIV Infections; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Dementia complex is a syndrome that affects a high percentage of AIDS patients. Neuroradiological findings may be non-specific and the diagnosis can be difficult in its earlier stages. Preliminary radionuclide studies have recently reported derangements of regional cerebral blood flow (CBF) which may be present before overt anatomical injury. This study reports on cortical and cerebellar CBF changes in 26 patients studied with 99Tcm-HM-PAO and single photon emission computed tomography (SPECT). Extensive cortical CBF derangements were observed in all patients and an evident cerebellar hypoperfusion was also present in three. The prevalence of hypoperfusion was highest in the frontal and parietal lobes. The extension of the hypoperfusion showed a highly significant correlation with the severity of the dementia complex (P less than 0.01 by chi 2 test). The SPECT also showed hypoperfused areas in three patients with normal CT scans and in two patients with normal MRI scans. These results confirm previous preliminary reports on the high prevalence of cortical hypoperfusion in dementia complex and suggest the use of this radionuclide technique to assist in the early diagnosis and follow-up of AIDS patients, especially when CT and MRI are still normal.

Topics: Adult; AIDS Dementia Complex; Cerebrovascular Circulation; Female; Humans; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon