Comparison of the Effect of Low- and Iso-Osmolar Contrast Agents on Heart Rate during Chest CT Angiography: Results of a Prospective Randomized Multicenter Study
Bibliographic record
Abstract
PURPOSE: To prospectively compare the effect of intravenous injection of low-osmolar iopamidol with that of intravenous injection of iso-osmolar iodixanol on heart rate (HR) during nongated chest computed tomographic (CT) angiography. MATERIALS AND METHODS: This multicenter study was approved by local institutional review boards, and patients provided written informed consent. Patient enrollment and examination at centers in the United States complied with HIPAA regulations. One hundred and thirty patients (54 male; mean age, 52 years) clinically suspected of having pulmonary embolism were referred for pulmonary CT angiography and were randomly assigned to receive 80 mL of either iopamidol (370 mg of iodine per milliliter, n = 63) or iodixanol (320 mg of iodine per milliliter, n = 67) at a rate of 4 mL/sec. HR (measured in beats per minute) was monitored from 5 minutes before the start of injection to the end of imaging, and precontrast HR and maximum postcontrast HR were recorded. Student t and χ(2) tests were used for continuous and categorical variables, respectively. RESULTS: Precontrast HR in patients who received iopamidol (mean, 81 beats per minute ± 18 [standard deviation]) was similar to that in patients who received iodixanol (mean, 77 beats per minute ± 17) (P = .16). Mean postcontrast HR was 87 beats per minute ± 17 and 82 beats per minute ± 18 (P = .16) in the iopamidol and iodixanol groups, respectively. Mean increase from precontrast HR to postcontrast HR was 5 beats per minute ± 9 and 5 beats per minute ± 7 (P = .72) in the iopamidol and iodixanol groups, respectively. Thirty-five (56%) of the 63 patients who received iopamidol and 33 (49%) of the 67 patients who received iodixanol had an HR increase of fewer than 5 beats per minute, 15 (24%) and 18 (27%) patients, respectively, had an increase of 5-9 beats per minute, and four (6%) and three (4%) patients, respectively, had an increase of more than 20 beats per minute. These proportions were not significantly different between the groups (P = .51, χ(2) test). CONCLUSION: High-rate intravenous administration of 80 mL of iopamidol and iodixanol during pulmonary CT angiography slightly increased HR; there was no difference in HR between the contrast agent groups.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.006 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".