Dual-isotope single-photon emission computerized tomography scanning in patients with glioblastoma multiforme: association with patient survival and histopathological characteristics of tumor after high-dose radiotherapy.

OBJECT: The study was conducted to determine the association between dual-isotope single-photon emission computerized tomography (SPECT) scanning and histopathological findings of tumor recurrence and survival in patients treated with high-dose radiotherapy for glioblastoma multiforme. METHODS: Studies in which SPECT with 201Tl and 99mTc-hexamethypropyleneamine oxime (HMPAO) were used were performed 1 day before reoperation in 47 patients with glioblastoma multiforme who had previously been treated by surgery and high-dose radiotherapy. Maximum uptake of 201Tl in the lesion was expressed as a ratio to that in the contralateral scalp, and uptake of 99mTc-HMPAO was expressed as a ratio to that in the cerebellar cortex. Patients were stratified into groups based on the maximum radioisotope uptake values in their tumor beds. The significance of differences in patient gender, histological characteristics of tissue at reoperation, and SPECT uptake group with respect to 1-year survival was elucidated by using the chi-square statistic. Comparisons of patient ages and time to tumor recurrence as functions of 1-year survival were made using the t-test. Survival data at 1 year were presented according to the Kaplan-Meier method, and the significance of potential differences was evaluated using the log-rank method. The effects of different variables (tumor type, time to recurrence, and SPECT grouping) on long-term survival were evaluated using Cox proportional models that controlled for age and gender. All patients in Group I (201Tl ratio < 2 and 99mTc-HMPAO ratio < 0.5) showed radiation changes in their biopsy specimens: they had an 83.3% 1-year survival rate. Group II patients (201Tl ratio < 2 and 99mTc-HMPAO ratio of > or = 0.5 or 201Tl ratio between 2 and 3.5 regardless of 99mTc-HMPAO ratio) had predominantly infiltrating tumor (66.6%); they had a 29.2% 1-year survival rate. Almost all of the patients in Group III (201Tl ratio > 3.5 and 99mTc-HMPAO ratio > or = 0.5) had solid tumor (88.2%) and they had a 6.7% 1-year survival rate. Histological data were associated with 1-year survival (p < 0.01): however, SPECT grouping was more closely associated with 1-year survival (p < 0.001) and was the only variable significantly associated with long-term survival (p < 0.005). CONCLUSIONS: Dual-isotope SPECT data correlate with histopathological findings made at reoperation and with survival in patients with malignant gliomas after surgical and high-dose radiation therapy.

Reversible cerebral hypoperfusion in Lyme encephalopathy.

Lyme encephalopathy (LE) presents with subtle neuropsychiatric symptoms months to years after onset of infection with Borrelia burgdorferi. Brain magnetic resonance images are usually normal. We asked whether quantitative single photon emission computed tomography (SPECT) is a useful method to diagnose LE, to measure the response to antibiotic therapy, and to determine its neuroanatomic basis. In 13 patients with objective evidence of LE, SPECT demonstrated reduced cerebral perfusion (mean perfusion defect index [PDI] = 255), particularly in frontal subcortical and cortical regions. Six months after treatment with 1 month of intravenous ceftriaxone, perfusion significantly improved in all 13 patients (mean PDI = 188). In nine patients with neuropsychiatric symptoms following Lyme disease, but without objective abnormalities (e.g., possible LE), perfusion was similar to that of the treated LE group (mean PDI = 198); six possible LE patients (67%) had already received ceftriaxone prior to our evaluation. Perfusion was significantly lower in patients with LE and possible LE than in 26 normal subjects (mean PDI = 136), but 4 normal subjects (15%) had low perfusion in the LE range. We conclude that LE patients have hypoperfusion of frontal subcortical and cortical structures that is partially reversed after ceftriaxone therapy. However, SPECT cannot be used alone to diagnose LE or determine the presence of active CNS infection.

Intratumoral administration of 5-[123I]iodo-2'-deoxyuridine in a patient with a brain tumor.

UNLABELLED: We have initiated a study in which patients suspected of having primary gliomas are given a single intracerebral injection of the thymidine analog 5-[123I]iodo-2'-deoxyuridine ([123I]IUdR). The purpose of the study is to determine the biodistribution of the radiopharmaceutical and to calculate dose estimates to the tumor and normal tissues. METHODS: A patient with a cystic glioma was injected with [123I]IUdR. Whole-body scans and brain scans were obtained at various times after injection, and blood, urine and stools were collected and assayed for radioactivity to assess its biodistribution and clearance. RESULTS: Scintigraphic imaging demonstrated that the distribution of radiolabeled IUdR was mainly confined to the tumor (injection site), stomach and bladder. Disappearance from the tumor site and blood clearance were delayed probably due to collection in the cystic lesion. Eighty percent of the injected dose was recovered in the urine. CONCLUSION: The pharmacokinetics of [123I]IUdR locoregionally administered to a human glioma in situ resembled those observed in a rat glioma model where administration of the radiopharmaceutical radiolabeled with the Auger electron emitter 125I was therapeutically effective.

Detection of intracranial abnormalities in patients with chronic fatigue syndrome: comparison of MR imaging and SPECT.

OBJECTIVE: Chronic fatigue syndrome is a recently characterized condition of unknown origin that is manifested by fatigue, flulike complaints, and neurologic signs and symptoms, including persistent headache, impaired cognitive abilities, mood disorders, and sensorimotor disturbances. This syndrome can be difficult to diagnose clinically or by standard neuroradiologic tests. We performed MR imaging and single-photon emission computed tomography (SPECT) in patients with chronic fatigue syndrome to compare the usefulness of functional and anatomic imaging in the detection of intracranial abnormalities. SUBJECTS AND METHODS: Sixteen patients who fulfilled the Centers for Disease Control, British, and/or Australian criteria for chronic fatigue syndrome had MR and SPECT examinations within a 10-week period. Axial MR and SPECT scans were analyzed as to the number and location of focal abnormalities by using analysis of variance with the Student-Newman-Keuls option. MR imaging findings in patients with chronic fatigue syndrome were compared with those in 15 age-matched control subjects, and SPECT findings in the patients with chronic fatigue syndrome were compared with those in 14 age-matched control subjects by using Fisher's exact test. The findings on MR and SPECT scans in the same patients were compared by using the Wilcoxon matched-pairs signed-ranks test. RESULTS: MR abnormalities consisted of foci of T2-bright signal in the periventricular and subcortical white matter and in the centrum semiovale; there were 2.06 foci per patient, vs 0.80 foci per control subject. MR abnormalities were present in eight (50%) of 16 patients, compared with three (20%) of 15 age-matched control subjects. Neither of these differences reached significance, although the power of the study to detect differences between groups was small. Patients with chronic fatigue syndrome had significantly more defects throughout the cerebral cortex on SPECT scans than did normal subjects (7.31 vs 0.43 defects per subject, p < .001). SPECT abnormalities were present in 13 (81%) of 16 patients, vs three (21%) of 14 control subjects (p < .01). SPECT scans showed significantly more abnormalities than did MR scans in patients with chronic fatigue syndrome (p < .025). In the few patients who had repeat SPECT and MR studies, the number of SPECT abnormalities appeared to correlate with clinical status, whereas MR changes were irreversible. CONCLUSION: SPECT abnormalities occur more frequently and in greater numbers than MR abnormalities do in patients with chronic fatigue syndrome. SPECT may prove to be useful in following the clinical progress of patients with this syndrome.

SPECT imaging of the brain: comparison of findings in patients with chronic fatigue syndrome, AIDS dementia complex, and major unipolar depression.

OBJECTIVE: 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. SUBJECTS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Thallium-201 technetium-99m HMPAO single-photon emission computed tomography (SPECT) imaging for guiding stereotactic craniotomies in heavily irradiated malignant glioma patients.

SPECT scanning with Tl-201 and Tc-99m offers a unique, inexpensive functional imaging modality to combine with CT stereotactic craniotomy for guiding resection of necrosis and/or tumour in patients treated with escalated doses of radiation (> 6000 cGy) by either brachytherapy or radiosurgery. Thirty-two cases were analyzed, with a detailed description of the imaging and operative techniques.

Detection of recurrent gliomas with quantitative thallium-201/technetium-99m HMPAO single-photon emission computerized tomography.

Deteriorating clinical status after high-dose radiation therapy for high-grade gliomas may be due to radiation changes or may signal recurrent or residual tumor mass. The two conditions cannot be distinguished reliably by computerized tomography (CT) or magnetic resonance (MR) imaging. The authors assessed the ability of sequential thallium-201 chloride (201Tl) and technetium-99m hexamethylpropylene amine oxime (99mTc HMPAO) single-photon emission CT (SPECT) to distinguish tumor recurrence from radiation changes after high-dose (greater than or equal to 600 cGy) radiation therapy for malignant gliomas. Preoperative tumor/nontumor uptake ratios were analyzed in 32 patients and correlated with the presence of gross tumor at the time of reoperation. In 12 of 13 patients with 201Tl tumor/scalp ratios of 3.5 or greater, recurrent tumor was present. The authors found 99mTc HMPAO SPECT to be useful for identifying the absence of solid tumor recurrence in patients with low to moderate 201Tl uptake (ratio 1.1 to 3.4) and low perfusion to that site. In 11 of 12 patients with 99mTc HMPAO tumor/cerebellum ratios of 0.50 or less, no recurrent tumor mass was present. Three of seven patients with 201Tl ratios of 3.4 or less and 99mTc HMPAO ratios of 0.51 or more had recurrent tumor found at surgery; thus the test was not predictive in this group. It is concluded that the use of sequential 201Tl and 99mTc HMPAO SPECT accurately identifies the presence of tumor recurrence versus radiation changes in most patients with high-grade astrocytomas who have undergone tumor resection and high-dose radiation therapy.