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Title: Simultaneous estimations of blood brain barrier (BBB) permeability and local cerebral blood volume (CBV) in human brain tumors with positron tomography and Ga-68 EDTA

Conference · · J. Nucl. Med.; (United States)
OSTI ID:6590988

Using Ga-68 EDTA and a two compartment model for diffusion across the BBB that includes a weighted subtraction term for determination of the relative CBV (compared to a normal region of brain with an intact BBB) or the absolute value of CBV (using measurements of Ga-68 concentrations in the blood: the input function), the authors determined values for the forward and reverse rate constants (k1 and k2) for diffusion across the BBB as well as values of CBV in 12 subjects with primary or metastatic brain tumors. Patients were studied on a NeuroECAT tomograph; imaging times were 1 to 10 minutes per scan for a total of about 2 hours. Measurements of Ga-68 concentrations were made on plasma arterial samples. Four direct measurements (in 3 subjects) of CBV using C(15-0) were also obtained. Values of k1 (the transfer constant which numerically approximates the capillary permeability surface area (PS) product) averaged 0.0030 (+- 0.0017) ml/min/gm while k2 averaged 0.0308 (+- 0.0157)/min. Linear regression analysis of the relative CBV in 7 tumor deposits in 4 paired Ga-68 EDTA/C(15-0) studies compared to normal brain tissues resulted in a correlation coefficient of 0.97 for the two methods. The estimates of k1 and k2 were insensitive to changes in the location of the control regions (although CBV estimates changed appropriately) as well as to substituting the input function for a normal brain region when determining the absolute CBV of the lesions.

Research Organization:
UCLA School of Medicine, Los Angeles, CA
OSTI ID:
6590988
Report Number(s):
CONF-840619-; TRN: 87-018909
Journal Information:
J. Nucl. Med.; (United States), Vol. 25:5; Conference: 31. annual meeting of the Society of Nuclear Medicine, Los Angeles, CA, USA, 5 Jun 1984
Country of Publication:
United States
Language:
English