Myocardial Perfusion Imaging in Takayasu Arteritis
Bibliographic record
Abstract
OBJECTIVE: Myocardial perfusion defects using scintigraphy have been frequently observed in patients with Takayasu arteritis (TA) without coronary stenosis. The aim of our study was to evaluate coronary microcirculation in TA using thallium-201 (201Tl) myocardial scintigraphy and dipyridamole (DPM) as vasodilator agent. METHODS: Twenty-five consecutive patients with TA were prospectively recruited. They were asymptomatic for cardiac issues and examined using 201Tl myocardial scintigraphy at rest and after coronary artery vasodilation with intravenous DPM. Factors associated with improvement in myocardial perfusion after DPM were identified in patients with TA. RESULTS: Among 25 patients with TA, 21 (84%) had 201Tl myocardial perfusion defects and 4 (16%) had normal resting myocardial perfusion. Using a 17-segments model for quantitative image analysis, DPM significantly improved resting 201Tl myocardial perfusion in 14 patients (61%) versus 9 patients without improvement (39%). We were able to examine coronary artery stenoses in 11 patients, including 10 patients with thallium perfusion defects, and significant coronary artery stenoses were present in only 2 patients (18.2%). No significant difference was found in traditional cardiovascular risk factors between TA patients with or without improvement of myocardial perfusion after DPM. The absence of improvement in myocardial perfusion after DPM tended to be closely associated with specific features and prognostic factors of TA, such as aortic regurgitation at diagnosis, renovascular hypertension, longer duration of TA disease, and male sex. CONCLUSION: We found the significantly high prevalence of myocardial perfusion defects mostly improved after vasodilation with DPM, which may indicate the major role of microcirculatory dysfunction in myocardial ischemia in TA.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| 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 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".