Measurement of regional cerebral plasma pool and hematocrit with copper-62-labeled HSA-DTS.
We developed copper-62-labeled human serum albumin-dithiosemicarbazone (62Cu-HSA-DTS) as a blood-pool imaging agent for PET. To evaluate 62Cu-HSA-DTS for plasma-pool imaging and to measure the regional cerebral hematocrit, 12 normal volunteers and 7 patients with cerebrovascular disease underwent PET studies with 62Cu-HSA-DTS and 15O-labeled carbon monoxide (C15O).


METHODS
The normal subjects were studied with both C15O and 62Cu-HSA-DTS. All patients were examined by 15O-gas studies to measure cerebral perfusion and oxygen metabolism, followed by measurement of plasma volume with 62Cu-HSA-DTS for analysis of regional cerebral hematocrit. Regional cerebral hematocrit was calculated from regional cerebral red cell volume (rCRCV) measured by C15O and regional plasma volume (rCPV) measured by 62Cu-HSA-DTS in each subject, and the regional cerebral/large-vessel hematocrit ratio was obtained for both cerebral hemispheres in each subject.


RESULTS
Mean regional cerebral hematocrit and mean cerebral/large-vessel hematocrit ratio in the 12 normal volunteers were 38.3 +/- 3.45% and 0.88 +/- 0.06, respectively. In the seven patients with cerebrovascular disease, regional cerebral hematocrit was significantly lower on the hypoperfused side than the normal hemisphere. The images of rCPV and rCRCV from these patients demonstrated a greater increase in rCPV than rCRCV in the hypoperfused area.


CONCLUSIONS
These results suggest that 62Cu-HSA-DTS can be used for measurement of plasma volume and that regional cerebral hematocrit may provide valuable information regarding the microcirculation in the brain.
Okazawa
H
H
Faculty of Medicine, Kyoto University, Japan.
Yonekura
Y
Y
Fujibayashi
Y
Y
Yamauchi
H
H
Ishizu
K
K
Nishizawa
S
S
Magata
Y
Y
Tamaki
N
N
Fukuyama
H
H
Yokoyama
A
A
Konishi
J
J
D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging*; D002248:Carbon Monoxide; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation / Q000502:physiology; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003301:Copper Radioisotopes; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D010104:Oxygen Radioisotopes; D010953:Plasma Volume / Q000502:physiology; D012709:Serum Albumin; D013882:Thiosemicarbazones; D014055:Tomography, Emission-Computed
D003301:Copper Radioisotopes; D009942:Organometallic Compounds; D010104:Oxygen Radioisotopes; D012709:Serum Albumin; D013882:Thiosemicarbazones; D002248:Carbon Monoxide