Correlation of 11C-methionine PET and diffusion-weighted MRI: is there a complementary diagnostic role for gliomas?
BACKGROUND
11C-Methionine (MET) PET and diffusion-weighted (DW) MRI are commonly used for evaluation of gliomas. We assessed the correlation between MET uptake and diffusion restriction measured on DW MRI in glioma.


METHODS
Thirty-one patients with gliomas, who were initially examined with MET PET and DW MRI, were enrolled retrospectively. MET PET and apparent diffusion coefficient (ADC) images were coregistered to each other, using rigid-body transformation. Tumor-to-normal count density ratio of the cortex (TNR) and normalized apparent diffusion coefficient (nADC) value were measured for each voxel on the MET PET and ADC map. The maximum TNR (TNRmax) and minimum nADC (nADCmin) were obtained for each tumor. Correlations between those parameters were evaluated.


RESULTS
The TNRmax and nADCmin values of a glioma were significantly correlated (r=-0.42). TNRmax and nADCmin were significantly correlated with glioma grades. Furthermore, TNRmax and nADCmin showed a trend for correlation with the Ki-67 index. We analyzed the correlation between voxel-based TNR and ADC within a tumor and observed no correlation between them. Regions with high MET uptake did not correspond with regions with low nADC.


CONCLUSIONS
We found a negative correlation between TNRmax and nADCmin for each glioma; however, MET uptake and ADC within a tumor were independent of each other and were heterogeneous. The two parameters represent different biological features; thus, as a comprehensive approach, MET PET and DW MRI might have a complementary role in the characterization of gliomas.
aDepartment of Nuclear Medicine, Seoul National University Hospital bDepartment of Neurosurgery, Seoul National University College of Medicine, Seoul National University Hospital cDepartment of Molecular Medicine and Biopharmaceutical Science, Graduate School of Convergence Science and Technology dCancer Research Institute eSchool of Chemical and Biological Engineering fCenter for Nanoparticle Research, Institute for Basic Science Seoul National University, Departments of gRadiology hPathology, Seoul National University College of Medicine, Seoul, Korea iDepartment of Radiological Sciences, University of California at Irvine, Irvine, California, USA.
Hongyoon
H
Choi
Jin Chul
JC
Paeng
Gi Jeong
GJ
Cheon
Chul-Kee
CK
Park
Seung Hong
SH
Choi
Hye Sook
HS
Min
Keon Wook
KW
Kang
June-Key
JK
Chung
Euishin Edmund
EE
Kim
Dong Soo
DS
Lee
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008297:Male; D008715:Methionine; D008875:Middle Aged; D049268:Positron-Emission Tomography; D055815:Young Adult
C086242:carbon-11 methionine; D008715:Methionine