Blood flow and metabolism of central neurocytoma: a positron emission tomography study.
BACKGROUND
New World Health Organization classifications have categorized central neurocytomas as neuronal tumors. The differential diagnosis between central neurocytomas and other tumors is important for selection of the optimal therapy modality for the management of intraventricular tumors. To characterize the pathophysiology and proliferating activity of central neurocytoma accurately, cerebral blood flow and metabolism in five patients with central neurocytoma were studied using positron emission tomography (PET).


METHODS
Tracers used for the present study included C15O2, C15O, 15O2, and 18F-fluorodeoxyglucose (FDG). Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction fraction (rOEF), cerebral metabolic rate of oxygen (rCMRO2), and cerebral metabolic rate of glucose (rCMRGl) were quantitatively analyzed in tumor lesions and the contralateral gray matter. Four patients with central neurocytoma underwent a complete PET study, including all circulatory and metabolic parameters; one patient was studied with 11C-methyl-L-methionine and FDG tracers.


RESULTS
Tumor rCBF and rCBV were higher than comparable values in the contralateral gray matter in three of four patients. This high level of perfusion corresponds to angiographic findings that show intense tumor staining in tumors fed by perforated arteries. Tumor rOEF and rCMRO2 were significantly lower than corresponding values in the gray matter (rOEF, P < 0.01; rCMRO2, P < 0.05 by Student's t test). Tumor rCMRGl ranged from 2.68 to 6.26 mg/100 ml/minutes and did not exceed contralateral gray matter values in any of the five patients. Tumor rCMRGl was significantly lower (P < 0.02) than the gray matter rCMRGl. One tumor exhibited a relatively high value of rCMRGl (comparable to gray matter rCMRGl), and increased in size 4 months after partial resection. No other tumors appeared during postoperative follow-up periods that ranged from 4 to 135 months.


CONCLUSIONS
Circulation and metabolism parameters measured by PET offer insight into the biologic characteristics of central neurocytoma. Tumor rCMRGl may be an indicator of the proliferating activity in central neurocytoma.
Mineura
K
K
Neurosurgical Service, Akita University Hospital, Japan.
Sasajima
T
T
Itoh
Y
Y
Sasajima
H
H
Kowada
M
M
Tomura
N
N
Uesaka
Y
Y
Ogawa
T
T
Hatazawa
J
J
Uemura
K
K
D000328:Adult; D001810:Blood Volume; D002250:Carbon Radioisotopes; D002551:Cerebral Ventricle Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000378:metabolism; D002560:Cerebrovascular Circulation; D003847:Deoxyglucose / Q000031:analogs & derivatives; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives; D008875:Middle Aged; D018306:Neurocytoma / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D014055:Tomography, Emission-Computed
D002250:Carbon Radioisotopes; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose; D008715:Methionine; C038344:methionine methyl ester; D005947:Glucose; D010100:Oxygen