SENSITIVITY AND SPECIFICITY OF TL-201 SINGLE-PHOTON EMISSION TOMOGRAPHY IN THE FUNCTIONAL DETECTION AND DIFFERENTIAL-DIAGNOSIS OF BRAIN-TUMORS

The aim of this retrospective study was to assess the contribution of thallium-201 single-photon emission tomography (SPET) in the detection and differential diagnosis of brain tumours. In 90 patients Tl-201 SPET was performed because of clinical or radiological suspicion of tumoral invasion, completed by technetium-99m hexamethylpropylene amine oxime and Tc-99m-sestamibi SPET in some patients. For all tumours, diagnosis was based on biopsy or autopsy. Other diagnoses were made only after clinical and radiological follow-up for at least 6 months. Histologically tumours consisted of astrocytoma stage I or II (number of patients, n=6), astrocytoma stage III (n=8), glioblastoma multiforme (n=14) and oligodendroglioma (n=3), brain metastasis (n=14), lymphoma (n=3), meningioma (n=3), pituitary adenoma (n=2), pineal tumour (n=1), colloid cyst (n=1) and craniopharyngioma (n=1). False-negative studies included pineal tumour (n=1), colloid cyst (n=1), craniopharyngioma (n=1), astrocytomas stage I or II (n=6) and stage III (n=3), oligodendroglioma (n=2) and metastasis in the brain stem (n=1). Additional metastases approximately < 1.5 cm were not detected in two patients and Tl-201 SPET underestimated tumoral extent in one patient suffering from glioblastoma multiforme (n=1). A false-positive positive study was obtained in a patient with skull metastasis (n=l). All 15 patients who were finally shown to suffer from ischaemic infarction had a normal SPET study 9-28 days after the onset of symptomatology. Of five patients with haemorrhagic infarction, studied within 2 weeks, four were false-positive. Of six patients with intracranial haemorrhage, studied 9-39 days later, one showed focal Tl-201 accumulation. Two further false-posi