[Validation of MRI and 18F-FDG-PET coregistration in patients with primary brain tumors].
OBJECTIVE
To evaluate the role of PET and MRI fused image study inpatients with primary brain tumors previously treated, to determine the presence of radionecrosis vs residual tumor viability.


METHODS
Primary brain tumors were diagnosed by biopse and MR. 18FDG-PET scan and T1 enhanced MRI follow-up studies were performed between 3 and 5 months after treatment. The 18F-FDG uptake was semiquantitavively calculated by a region-of-interest based Tumor hotspot/normal brain tissue index.


RESULTS
Fifty-seven patients were studied, 37 had high grade gliomas; 9 had oligoastrocytomas; 5 had Embrionary tumors; I had a meningyoma and I had an oliodendroglial tumor. All MR studies showed tumor enhancement, without determine wether if it was radionecrosis or tumor viability. PET/MR fused study diagnosed 21 negative studies (30%) and 36 positive results (70%). Tumor hotspot/normal brain tissue index correlated well with the visual analysis registered.


CONCLUSIONS
Visual analysis in the contrast enhanced MR overestimates the tumoral area, without defining a possible diagnosis between tumor viability and radionecrosis. Metabolic activity in the 18F-FDG PET study in the enhanced area, determines the presence of residual tumor viability. Therefore, coregistration can be used to obtain a more specific diagnosis optimizing the cinical use.
Ortega-López
Nayelli
N
Unidad PET-Ciclotrón, Facultad de Medicina, Universidad Nacional Autónoma de México, México, DF, México. nayeortega2000@yahoo.com.mx
Mendoza-Vásquez
Raúl Guillermo
RG
Adame-Ocampo
Gloria
G
Alexanderson-Rosas
Erick
E
Cayetano-Alcaraz
Axel Alberto
AA
Angel-Celis
Miguel
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D003627:Data Interpretation, Statistical; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D005910:Glioma / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009336:Necrosis; D049268:Positron-Emission Tomography / Q000379:methods*; D011832:Radiation Injuries / Q000175:diagnosis / Q000000981:diagnostic imaging; D019275:Radiopharmaceuticals
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18