Measurement of Cerebral Blood Flow Using Graph Plot Analysis and I-123 Iodoamphetamine
Bibliographic record
Abstract
PURPOSE: 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. RESULT: 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.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".