The differential diagnosis of recurrent astro-glioma and radiological necrosis with MRI, CT and SPECT

Purpose: To study the specific features of recurrent astro-glioma and radiational necrosis on MRI, CT and SPECT. Materials and methods: Fifty-five patients of recurrent tumors and 5 patients of radiological necrosis were imaged on with CT or MRI and proved by second operation and pathology. Thirteen cases of nonrecurrence verified by clinical course and follow-up CT or MRI were taken as control group. The images were acquired with Diasonic 0.5 MTS imager and Eliscint 2400 CT scanner; Magnevist and Omnipaque were used as contrast medium respectively on MRI and CT; SPECT was done on APEX 409 AG SPECT image with 99mTc-MIBI. Results: It is found that (1) The operative patterns were closely related to the rate of tumor recurrence, but not related to recurrent type which classified as primary type, expanded type, and distant type. (2) 87% of recurrence and 80% of radiological necrosis were found within 2 years of after operation. (3) 100% of recurrent tumor in this study displayed post-operative active growing syndrome on CT or MRI. Finger-like edema could be seen in radiological necrosis. (4) Most recurrent tumors showed nodule-or ring-like contrasted study while map-like enhancement or non-enhanced were considered as specific feature of radiological necrosis. Conclusion: In patients with astro-glioma postoperative, follow up pre- and post-contrasted scan using CT or MRI within 2 years after operation is very helpful in defecting and for differentiating recurrent tumor from radiological necrosis with 100% of specificity