Neuroimaging in pediatric brain tumors: Gd-DTPA-enhanced, hemodynamic, and diffusion MR imaging compared with MR spectroscopic imaging.
OBJECTIVE
Gadolinium-enhanced MR images assist in defining tumor borders; however, the relation between tumor cell extent and contrast-enhanced regions is unclear. Our aim was to improve conventional neuroimaging of pediatric brain tumors with hemodynamic, diffusion, and spectroscopic MR imaging.


METHODS
We performed conventional MR and MR spectroscopic imaging in 31 children with neuroglial brain tumors. Hemodynamic MR imaging was performed in 16 patients with a first-pass intravenous bolus of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA); apparent diffusion coefficients (ADCs) were measured in 12 patients. To account for multiple measurements in a patient, we used a nested analysis of variance.


RESULTS
At MR spectroscopy, choline (Cho)-containing compounds (indicating tumor) and lipid levels (indicating necrosis) did not correlate with percent Gd-DTPA enhancement on MR images. Percent enhancement was positively correlated with relative cerebral blood volumes (rCBVs) (P =.05) and negatively correlated with ADCs (P <.001). Stepwise multiple linear regression revealed that rCBV (P =.008), ADC (P =.022), and lipid (P <.001) levels were significant independent predictors of percent enhancement. Tumor spectral patterns were detected in tumor regions and outside enhancing tumor beds in patients with clinical progression; these were confirmed at neuropathologic analysis.


CONCLUSIONS
MR spectroscopic imaging improves the assessment of pediatric brain tumors by adding biochemical information regarding tumor involvement and by depicting residual or recurrent tumor outside the Gd-DTPA-enhanced tumor bed. rCBV and ADC mapping complemented MR spectroscopic imaging. We recommend the use of MR spectroscopic imaging in addition to conventional MR imaging in assessing pediatric brain tumors.
Tzika
A Aria
AA
Department of Radiology, Children's Hospital, Harvard Medical School, Boston, MA 02114, USA.
Zarifi
Maria K
MK
Goumnerova
Liliana
L
Astrakas
Loukas G
LG
Zurakowski
David
D
Young-Poussaint
Tina
T
Anthony
Douglas C
DC
Scott
R Michael
RM
Black
Peter McL
PM
D000293:Adolescent; D001810:Blood Volume; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D002794:Choline / Q000378:metabolism; D003287:Contrast Media; D004058:Diffusion; D018450:Disease Progression; D019786:Gadolinium DTPA; D006801:Humans; D007223:Infant; D050356:Lipid Metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D018365:Neoplasm, Residual / Q000175:diagnosis
D003287:Contrast Media; D019786:Gadolinium DTPA; D002794:Choline