PET: Blood flow and oxygen consumption in brain tumors
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Tissue perfusion and cerebral energy metabolism in brain tumor patients are regionally abnormal, and certain patterns of pathological changes may be demonstrated in and around tumor tissue. Tumor CBF may vary widely between subjects, whereas oxygen extraction is almost always markedly reduced. This is in apparent contradiction with the tumor tissue oxygen tension data (see previous chapter): since these are low, an increase of OER would be expected. Still, as discussed above, oxygen consumption calculated from oxygen tension or PET data yield the same relative decreases (0.3) of tumor oxygen utilization compared to normal brain. This suggests that the characteristic pathological changes of tumor cell energy metabolism have diminished oxygen demand and changed the level of coupling between CBF and OER.
Since all published data on OER in tumor patients have been obtained by the steady state method, possibly resulting in an underestimation of OER, it will be mandatory to apply dynamic oxygen uptake measurements to circumvent this methodological problem and e.g. to make use of distribution volume of water to correct for tissue composition as has been reported in one paper studying patients with breast tumors.
Because of the conspicuous regional changes in tumor oxygen metabolism it is expected that effectivity of chemotherapeutic measures is directly reflected by characteristical adaptations of metabolism. Systematic studies in this context have not been reported to date. Whether oxygen metabolism changes would be more sensitive than just CBF measurements as indicator of treatment effectivity remains to be seen.
Key wordspositron emission tomography brain tumors blood flow oxygen consumption
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- 1.Lammertsma AA, Jones T: Low oxygen extraction fraction in tumours measured with the oxygen-15 steady state technique: effect of tissue heterogeneity. Br J Radiol 65: 697–700, 1992Google Scholar
- 2.Wilson CB, Lammertsma AA, McKenzie CG, Sikora K, Jones T: Measurement of blood flow and exchanging water space in breast tumors using positron emission tomography: A rapid and noninvasive dynamic method. Canc Res 52: 1592–1597, 1992Google Scholar
- 3.Leenders KL, Beaney RP, Brooks DJ, Lammertsma AA, Heather JD, McKenzie CG: Dexamethasone treatment of brain tumor patients: Effects on regional cerebral blood flow, blood volume, and oxygen utilization. Neurol 35: 1610–1616, 1985Google Scholar
- 4.Ito M, Lammertsma AA, Wise RJS, Bernardi S, Frackowiack RSJ, Heather JD, McKenzie GG, Thomas DGT, Jones T: Measurement of regional cerebral blood flow and oxygen utilization in patients with cerebral tumors using15O and positron emission tomography: Analytical techniques and preliminary results. Neuroradiol 23: 63–74, 1982Google Scholar
- 5.Ogawa T, Uemura K, Shishido F, Yamaguchi T, Murakami M, Inugami A, Kanno I, Sasaki H, Kato T, Hirata K, Kowada M, Mineura K, Yasuda T: Changes of cerebral blood flow, and oxygen and glucose metabolism following radiochemotherapy of gliomas: A PET study. J Comp Ass Tomogr 12: 290–297, 1988Google Scholar
- 6.Tyler JL, Diksic M, Villemure JG, Evans AC, Yamamoto YL, Feindel W: Metabolic and hemodynamic evaluation of gliomas using positron emission tomography. J Nucl Med 28: 1123–1133, 1987Google Scholar
- 7.Rhodes CG, Wise RJ, Gibbs JM, Frackowiak RS, Hatazawa J, Palmer AJ, Thomas DG, Jones T:In vivo disturbance of the oxidative metabolism of glucose in human cerebral gliomas. Ann Neurol 14: 614–626, 1983Google Scholar
- 8.Mineura K, Suda Y, Yasuda T, Kowada M, Ogawa T, Shishido F, Uemura K: Early and late stage positron emission tomography (PET) studies on the hemocirculation and metabolism of seemingly normal brain tissue in patients with gliomas following radiochemotherapy. Acta Neurochir (Wien) 93: 110–115, 1988Google Scholar
- 9.Mineura K, Yasuda T, Kowada M, Ogawa T, Shishido F, Uemura K: Positron emission tomographic evaluation of radiochemotherapeutic effect on regional cerebral hemocirculation and metabolism in patients with gliomas. J Neuro-Oncology 5: 277–285, 1987Google Scholar
- 10.Beaney RP, Brooks DJ, Leenders KL, Thomas DG, Jones T, Hainan KE: Blood flow and oxygen utilization in the contralateral cerebral cortex of patients with untreated intracranial tumors as studied by positron emission tomography, with observations on the effect of decompressive therapy. J Neurol Neurosurg Psych 48: 310–319, 1985Google Scholar
- 11.Leenders KL, Findley LJ, Cleeves L: PET before and after surgery for tumor-induced parkinsonism. Neurol 36: 1074–1078, 1986Google Scholar
- 12.Hino A, Imahori Y, Tenjin H, Mizukawa N, Ueda S, Hirakawa K, Nakahashi H: Metabolic and hemodynamic aspects of peritumoral low-density areas in human brain tumor. Neurosurg 26: 615–621, 1990Google Scholar
- 13.Lammertsma AA, Wise RJ, Cox TC, Thomas DG, Jones T: Measurement of blood flow, oxygen utilization, oxygen extraction ratio, and fractional blood volume in human brain tumours and surrounding oedematous tissue. Br J Radiol 58: 725–734, 1985Google Scholar