Sestamibi technetium-99m brain single-photon emission computed tomography to identify recurrent glioma in adults: 201 studies.

OBJECT: In the follow-up of treated gliomas, CT and MRI can often not differentiate radionecrosis from recurrent tumor. The aim of this study was to assess the interest of functional imaging with (99m)Tc-MIBI SPECT in a large series of 201 examinations. METHOD: MIBI SPECT were performed in 81 patients treated for brain gliomas. A MIBI uptake index was computed as the ratio of counts in the lesion to counts in the controlateral region. SPECT was compared to stereotactic biopsy in 14 cases, or in the others cases to imaging evolution or clinical course at 6 months after the last tomoscintigraphy Two hundred and one tomoscintigraphies were performed. One hundred and two scans were true positive, 82 scans were true negative. Six scans were false positive (corresponding to 3 patients): 2 patients with an inflammatory reaction after radiosurgery, 1 with no explanation up to now. Eleven scans were false negative (5 patients): 1 patient with a deep peri-ventricular lesion, 2 patients with no contrast enhancement on MRI, 2 patients with a temporal tumor. The sensitivity for tumor recurrence was 90%, specificity 91.5% and accuracy 90.5%. We studied separately low and high grade glioma: sensitivity for tumor recurrence was respectively 91% and 89%, specificity 100% and 83% and accuracy 95% and 87%. MIBI SPECT allowed the diagnose of anaplasic degenerence of low grade sometimes earlier than clinical (5 cases) or MRI signs (7 cases). CONCLUSIONS: Our results confirm the usefullness of MIBI SPECT in the follow-up of treated gliomas for the differential diagnosis between radiation necrosis and tumor recurrence.

Evaluation of methods to detect interhemispheric asymmetry on cerebral perfusion SPECT: application to epilepsy.

UNLABELLED: Detecting perfusion interhemispheric asymmetry in neurologic nuclear medicine imaging is an interesting approach to epilepsy. METHODS: This study compared 4 methods that detect interhemispheric asymmetries of brain perfusion in SPECT. The first (M1) was conventional side-by-side expert-based visual interpretation of SPECT. The second (M2) was visual interpretation assisted by an interhemispheric difference (IHD) volume. The last 2 were automatic methods: unsupervised analysis using volumes of interest (M3) and unsupervised analysis of the IHD volume (M4). Use of these methods to detect possible perfusion asymmetry was compared on 60 simulated SPECT datasets by controlling the presence and location of asymmetries. From the detection results, localization receiver operating characteristic curves were generated and areas under curves were estimated and compared. Finally, the methods were applied to analyze interictal SPECT datasets to localize the epileptogenic focus in temporal lobe epilepsies. RESULTS: This study showed an improvement in asymmetry detection on SPECT images with the methods using IHD volume (M2 and M4), in comparison with the other methods (M1 and M3). However, the most useful method for analyzing clinical SPECT datasets appeared to be visual inspection assisted by the IHD volume, since the automatic method using the IHD volume was less specific. CONCLUSION: The use of quantitative methods can improve performance in detection of perfusion asymmetry over visual inspection alone.