Measurement of cerebral blood flow using graph plot analysis and I-123 iodoamphetamine.
OBJECTIVE
N-isopropyl-p[I-123]iodoamphetamin (IMP) is transiently taken up by the lungs after intravenous injection and its concentration in arterial blood varies depending on the degree of I-123 IMP uptake and subsequent washout. A method that does not require arterial blood sampling would be valuable to measure cerebral blood flow (CBF) using I-123 IMP.


METHODS
The authors developed a new theory and a convenient new method of CBF determination using I-123 IMP that does not require blood sampling. Dynamic images of the head and chest were acquired immediately after intravenous injection of I-123 IMP in a series of 42 consecutive patients with cerebrovascular disorders or other brain diseases (31 men, 11 women; mean age, 58 +/- 11 years). Changes in the I-123 IMP counts of the regions of interest set in the head and pulmonary trunk were analyzed by the graph plot method, and the F values (CBF index slope) determined were compared with the mean CBF levels obtained by simultaneous autoradiography.


RESULTS
The F values correlated well with the mean CBF obtained by autoradiography (r = 0.818, P < 0.001).


CONCLUSIONS
This innovative I-123 IMP graph plot analysis method using the time-activity curve of the head and pulmonary trunk alone is a noninvasive, convenient way to measure CBF. It is expected to become the most useful clinical technique for measuring CBF with I-123 IMP. This method can be used for patient follow-up and for comparing different patient groups evaluated in regional CBF studies.
Okamoto
Kunio
K
Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Ushijima
Yo
Y
Okuyama
Chio
C
Nakamura
Tomoki
T
Nishimura
Tsunehiko
T
D000662:Amphetamines; D001345:Autoradiography; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012039:Regional Blood Flow; D013997:Time Factors
D000662:Amphetamines; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; C041336:4-iodoamphetamine