Study designs of evaluations included in the review
Studies that included at least 6 patients with confirmed tumour recurrence were eligible for inclusion.
Specific interventions included in the review
Studies that evaluated 201-Tl SPECT for the detection of tumour recurrence were eligible for inclusion. The 201-Tl dose ranged from 111 to 148 MBq. The time interval from tracer injection to scanning ranged from 5 to 10 minutes to 3 hours. The reference region of interest was either the mirror image (contralateral hemisphere) or contralateral scalp. The definition of a positive SPECT scan was based on a tumour-non tumour ratio ranging >=0.5 to >=3.5.
Reference standard test against which the new test was compared
Studies in which histopathological confirmation of the suspected brain lesion or cytological examination of cerebrospinal fluid (CSF) for tumour cells was used as the reference standard were eligible for inclusion. Clinical follow-up was not considered to be a valid reference standard.
Participants included in the review
Studies of patients who had previously received radiotherapy for supratentorial glioma and who were clinically suspected to have recurrent tumour growth were eligible for inclusion. Glioma was considered to include astrocytic, oligodendroglial or ependymal tumours, or mixed gliomas, based on the World Health Organization classification of tumours of the nervous system. Patients with various types of glioma were included, although most had high-grade gliomas. The patients had received different types and dosages of radiotherapy. Some patients had also previously received chemotherapy. The mean age of the participants ranged from 43 to 57 years and the overall age from 9 to 84 years. The prevalence of tumour recurrence ranged from 33 to 100%.
Outcomes assessed in the review
Studies had to report sufficient data to construct a 2x2 table of test performance to be included. The outcomes reported in the review were the sensitivity, specificity and diagnostic odds ratio (DOR).
How were decisions on the relevance of primary studies made?
Two reviewers independently selected studies for inclusion in the review. Any disagreements were resolved through consensus, or by referral to a third reviewer if necessary.