Kinetic analysis of IMP split dose method for two consecutive measurement of cerebral blood flow
- Kyoto Univ. Faculty of Medicine (Japan); and others
The split dose method for two consecutive measurements of cerebral blood flow (CBF) with I-123 IMP seems to offer a great merit to the SPECT study of the brain. However, because of complexity of the dynamics of IMP, it is not clear if microsphere (MS) model permits a estimation of CBF for the 2nd dose. We applied kinetic (KN) analysis based on 2 compartment model to the dynamic SPECT scan data, and compared the results with those obtained by MS model. Dynamic SPECT (1-min scans for 50 min) was performed using 3-head SPECT camera in 5 patients to test the reproducibility of measured CBF and in 9 patients to test the vascular response to acetazolamide (ACZ). Two doses of IMP (111 MBq each) were injected at the time of, and 25 min after, the scan initiation. ACZ (1g) was administered at 13 min. Arterial blood samples were drawn manually during the scan and an octanol extracted input function was obtained. Dynamic scan data for 22 min was used for CBF by KN analysis (K1), and 4-min scan data at 5 min for CBF by MS model (Km), for each dose. For 2nd CBF by MS model, simple subtraction of brain activity due to the I st dose was done using 4-min scan data just prior to the 2nd dose. Reproducibility of measured CBF by KN analysis was excellent (r=0.949, 1st K1=39.2{plus_minus}5.6 and 2nd K1=38.5{plus_minus}6.6 ml/l00g/min: mean{plus_minus}SD). Vascular response to ACZ was good (1st K1=42.4{plus_minus}7.8 to 2nd K1=67.9{plus_minus}10.0) in areas without ischemia, but poor (1st K1=41.1{plus_minus}8.5 to 2nd K1=46.1{plus_minus}11.1) in ischemic areas. Compared to KN analysis, MS model underestimated 3.5% for the 1st CBF measurement and 12.8% for the 2nd. However, excellent correlation was observed not only between 1st K1 and Km (r=0.993, slope=0.920) but between 2nd K1 and Km (r=0.994, slope=0.814), and the results permitted a reasonable correction for Km.
- OSTI ID:
- 198062
- Report Number(s):
- CONF-940605-; ISSN 0161-5505; TRN: 95:007029-0214
- Journal Information:
- Journal of Nuclear Medicine, Vol. 35, Issue Suppl.5; Conference: 41. annual meeting of the Society of Nuclear Medicine, Orlando, FL (United States), 5-8 Jun 1994; Other Information: PBD: May 1994
- Country of Publication:
- United States
- Language:
- English
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