Recurrent cerebral gliomas in MRI and Iodine-123[corrected]-alpha-methyl-tyrosine SPECT: the use of digitally fused images.

Background: Early detection and site location of recurrent cerebral glioma helps design optimum therapeutic regimen, which contributes to prolonged survival time of the patients. However, diagnosing the neoplastic growth at the post-resection site is a difficult process. The diagnostic modality to provide the most extensive morphological data is dynamic MR tomography. On the other hand, the tumour-related metabolic changes can be best diagnosed using the PET and SPECT techniques of nuclear medicine that employ radiolabelled amino acid 131 I-alpha-metyl-tyrosine (IMT) as the tracer. Thus, for comprehensive diagnostics of brain tumours, it is most effective to combine both the modalities and evaluate the fused images. The aim of the present study was to verify the usefulness of the calculated algorithm for a digital fusion of RM/SPECT images for the assessment of post-resection site of cerebral gliomas.

Material And Methods: The findings of MR and SPECT imaging for 21 patients who had surgery for cerebral glioma were subject to assessment. Diagnosis was based on histopathology results (8 cases of anaplastic astrocytoma and 13 cases of multiform glioblastoma). The site and size of the contrast enhancement areas from MR was compared with the hot focus location from SPECT.

Results: The study confirmed the feasibility of digital fusion of images yielded by SPECT and MR. The fused images reflect the non-homogeneity of the post-resection site of cerebral gliomas. Contrast enhancement areas only partially overlapped with the hot foci which, furthermore, were found to be substantially smaller.

Conclusions: The consistency of tumour locations detected with MR and SPECT was higher for tumours of the anaplastic astrocytoma type than for multiform glioblastomas (higher polymorphism of pathological changes).