Assessment of Left Ventricular Ejection Fraction with multifocal collimators: Comparison between IQ-SPECT, Planar Equilibrium Radionuclide Angiography, and Cardiac Magnetic Resonance
Bibliographic record
Abstract
511 Background: IQ-SPECT has been shown to significantly reduce acquisition time and administered dose while preserving image quality in myocardial perfusion imaging. The accuracy of gated blood-pool SPECT (GBPS) with IQ-SPECT to assess left ventricular ejection fractions (LVEF) and left ventricular end diastolic volumes (LVEDV) remains unknown. The purpose of this study is to compare LVEF and LVEDV obtained with IQ-SPECT to planar ventriculography and cardiac magnetic resonance imaging (cMRI). Methods: Sixty consecutive patients who underwent IQ-SPECT GBPS and planar imaging were included. Among those patients, 11 also underwent cMRI within 30 days of their GBPS. IQ-SPECT LVEF and LVEDV were calculated automatically using 2 validated software: QBS and MHI (Harel et al, 2007, 2010). IQ-SPECT LVEF measurements were compared to planar LVEF and cMRI LVEF. IQ-SPECT LVEDV measurements were compared to cMRI LVEDV. Results: Average ± SD planar LVEF was 48 ± 11 % (range 23 to 70 %) and average GBPS LVEDV was 177 ± 59mL (range 63 to 342 mL). Average ± SD GBPS LVEF were 40 ± 12 % and 44 ± 12 % with QBS and MHI respectively. Correlation coefficients between IQ-SPECT and planar LVEF were r=0.70 and r=0.83 for QBS and MHI respectively. Correlation coefficient between cMRI and planar LVEF was 0.69. Correlation coefficients between cMRI and GBPS LVEF were 0.52 and 0.65 using QBS and MHI respectively. Correlation coefficient between cMRI and GBPS LVEDV was 0.80 with both QBS and MHI. There was no significant correlation between the planar and GBPS LVEF difference versus LVEDV with QBS (r=0.03, p=0.81) and MHI (r=0.14, p=0.29). Conclusions: : LVEF calculated with GBPS using IQ-SPECT correlates well with planar measurements for a broad range of LVEF and LVEDV. Correlation is best using the MHI method and variation is independent of LVEDV. Furthermore, there is very good correlation between LVEDV measured with GBPS using IQ-SPECT and cMRI. These results suggest that IQ-SPECT can be used for the assessment of LVEF and LVEDV with GBPS.
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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 | 0.001 | 0.003 |
| 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".