Cerebral oxygen and glucose metabolism and blood flow in mitochondrial encephalomyopathy: a PET study.
Cerebral blood flow (CBF), oxygen metabolism (CMRO2), and glucose metabolism (CMRGlc) were measured using positron emission tomography in five patients diagnosed as having mitochondrial encephalomyopathy. The molar ratio between the oxygen and glucose consumptions was reduced diffusely, as CMRO2 was markedly decreased and CMRGlc was slightly reduced. The CBF showed less changes. The CBF increase on hypercapnia was smaller than normal, though this was not significant. CBF with hypocapnia demonstrated a significant reduction compared with the normal. These results suggest that oxidative metabolism is impaired and anaerobic glycolysis relatively stimulated, due to a primary defect of mitochondrial function, and that mild lactic acidosis occurs in brain tissue because of impaired utilisation of pyruvate in the TCA cycle. As these findings appear to indicate directly a characteristic of this disease, such measurements may be a useful tool for assessment of the pathophysiology and for diagnosis of mitochondrial encephalomyopathy.
Shishido
F
F
Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels-Akita, Japan.
Uemura
K
K
Inugami
A
A
Tomura
N
N
Higano
S
S
Fujita
H
H
Sasaki
H
H
Kanno
I
I
Murakami
M
M
Watahiki
Y
Y
Nagata
K
K
D000140:Acidosis, Lactic / Q000000981:diagnostic imaging / Q000503:physiopathology; D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D001921:Brain / Q000098:blood supply*; D002648:Child; D003937:Diagnosis, Differential; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006019:Glycolysis / Q000502:physiology; D006801:Humans; D006935:Hypercapnia / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008928:Mitochondria / Q000502:physiology; D017237:Mitochondrial Encephalomyopathies / Q000000981:diagnostic imaging* / Q000503:physiopathology; D010101:Oxygen Consumption / Q000502:physiology*; D012016:Reference Values; D012039:Regional Blood Flow / Q000502:physiology; D014055:Tomography, Emission-Computed
D001786:Blood Glucose