Use of thallium-201 SPECT to quantitate malignancy grade of gliomas

Abstract

A quantitative preoperative technique using thallium-201 single-photon emission computerized tomography is described which predicts whether specific gliomas are of high- or low-grade malignancy. An index, based on the ratio of thallium uptake in the tumor versus the homologous contralateral brain, was calculated and compared with tumor histology. The index in 14 patients with low-grade malignant gliomas was 1.27 +/- 0.40 in contrast to an index of 2.40 +/- 0.61 in 11 patients with high-grade malignant gliomas (p less than 0.0005). Whether gliomas were of low- or high-grade malignancy could be predicted with 89% accuracy using a threshold of 1.5. Low-grade gliomas with an index higher than 1.5 acted biologically more like high-grade tumors, and no tumor histologically classified as being of high-grade malignancy had an index lower than 1.7. This technique could help to reduce unrecognized sampling errors during needle biopsies of brain tumors, particularly of high-grade lesions classified in error as low-grade tumors due to inadequate biopsy material.

Multimodality image fusion in dose escalation studies of brain tumors

“…The conventional MRI sequences might enhance the necrotic regions as well as the active tumor, whereas the SPECT/PET images can differentiate the two 9 , 16 . The single voxel proton magnetic resonance spectroscopy (MRS) and imaging, MRSI) has the potential to distinguish tumor relapse/necrosis and correlation of tumor grade 17 , 18 , 19 , 20 .…”

Comparison of Gadolinium-Enhanced MR and Thallium-201 Single Photon Emission Computed Tomography in Pediatric Brain Tumors

“…Even with the use of contrast agents, radiation necrosis may be indistinguishable from residual or recurrent tu mor on MR and CT [7], Although hypermetabolic tumor may be distinguishable from radiation necrosis on PET scanning, PET is expensive, not widely available, and has not been used to any extent in pediatric brain tumors [1,3], Tl-SPECT has been used in adults to differentiate high-grade gliomas from radiation necrosis [1,3]. Thal lium is a potassium analog which is transported into cells by a Na-K-ATPase-dependent pump and other cotrans port systems [1,7], Thallium uptake depends on cell membrane permeability, tumor type, regional blood How, and blood-brain barrier permeability and is not affected by steroid administration [3], Intense thallium uptake by neoplastic cells depends on active tumor metabolism.…”

“…Thal lium is a potassium analog which is transported into cells by a Na-K-ATPase-dependent pump and other cotrans port systems [1,7], Thallium uptake depends on cell membrane permeability, tumor type, regional blood How, and blood-brain barrier permeability and is not affected by steroid administration [3], Intense thallium uptake by neoplastic cells depends on active tumor metabolism. Regions of moderate thallium uptake may represent reac tive changes due to radiation damage without the pres ence of active tumor, cerebral candidiasis, bacterial ab scesses, hematomas, and infarcts [1,3,[8][9][10], In the set ting of malignant supratentorial gliomas, a thallium index <1.5 almost excludes the probability that the lesion is malignant [1]. However, the thallium index below which a lesion is probably not malignant has not been defined in pediatric brain tumors.…”

“…Thallium indices did not correlate with histologic grade, biologic aggressiveness, or tumor type. We were unable to establish indications for the use of thallium SPECT in this setting as there was little clinically useful information derived from thallium SPECT that was not provided by Gd-MR.Brain imaging with thallium-201 single photon emis sion computed tomography (Tl-SPECT) has been used in adults with supratentorial glial tumors to predict histo logic grade and to differentiate residual or recurrent tumor from the effects of radiotherapy [1][2][3]. Because…”

Differential Diagnosis Between Radiation Necrosis and Glioma Progression Using Sequential Proton Magnetic Resonance Spectroscopy and Methionine Positron Emission Tomography

“…Several neuroimaging modalities have been assessed for the differential diagnosis of radiation necrosis and tumor recurrence. Thallium-201 single photon emission computed tomography and [ 18 F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) can predict the malignancy of a tumor before treatment, 4,7,29) and are sensitive but relatively nonspecific for the differential diagnosis of tumor recurrence and radiation necrosis. 3,5,16) FDG-PET measurement of regional cerebral metabolism of glucose is useful for the assessment of tumor viability, 7) but cannot distinguish necrosis from recurrent tumor because 20,28) The recent widespread availability of magnetic resonance (MR) imaging and development of image processing sequences including proton MR spectroscopy ( 1 H-MRS) now allow follow up at short intervals.…”