Improved quantification of mitral regurgitant volume after MitraClip implantation using four-dimensional flow cardiac magnetic resonance imaging with dynamic valve tracking
Bibliographic record
Abstract
A 78-year-old man was referred to our hospital for MitraClip implantation after treatment for decompensated heart failure. Transthoracic echocardiography (TTE) revealed severe mitral regurgitation (MR) with eccentric swirling jets reaching the posterior left atrium due to mitral valve prolapse (Panel A). However, TTE performed suboptimal quantification of MR due to the jet eccentricity; thus, cardiovascular magnetic resonance (CMR) was used instead. Standard CMR methods indirectly quantify MR by subtracting aortic forward flow from the left-ventricular stroke volume. Four-dimensional flow CMR with dynamic valve tracking (4D-DVT) quantifies MR directly with frame-by-frame correction of the annular valve plane motion. The preoperative MR volume was measured at 73 mL using 4D-DVT and at 84 mL using the standard method (Panel B, see Supplementary material online, Video S1, Video Still Image 1). At the 1 year follow up, MR volume quantification was hindered by metal artefacts and multiple jets from the two-clip implantation on TTE (Panel C). However, cine CMR demonstrated a significant reduction in the left-ventricle end-diastolic volume index from 137 to 43 mL/m2 (Panels D and E), and 4D-DVT showed that the MR volume was reduced to 24 mL (Panel F, see Supplementary material online, Video S2, Video Still Image 2). The standard CMR method showed an illogical MR volume reduction of −13 mL. The optimal region of interest for 4D-DVT was just above the annules to avoid artefacts from the clips. Serial 4D-DVT assessment is potentially more versatile and accurate than the standard CMR method or TTE to quantify MR, especially in patients with metal artefacts or eccentric jets. Panel A: Preoperative TTE showed mitral valve prolapse, which caused severe MR with eccentric swirling jets in the left atrium. Panel B: Eccentric MR jets were also observed in the left atrium (arrowheads) on 4D-DVT pathline imaging, from which a preoperative MR volume of 73 mL was derived. CMR data analysis was performed using cmr42 (Circle Cardiovascular Imaging, Canada). Panel C: Repeat TTE at 1 year showed mitral valves repaired by implantation of two clips. Colour Doppler imaging qualitatively revealed mild MR with multiple jets due to clips. Panel D: Cine CMR revealed left-ventricular dilatation (LVEDVi = 137 mL/m2) before implantation of clips with a preserved ejection fraction (LVEF = 54%). Panel E: Follow-up cine CMR indicated that cardiac morphology had markedly improved (LVEDVi = 43 mL/m2) 1 year after clip implantation. Panel F: Serial 4D-DVT imaging demonstrated a reduction in MR volume of 24 mL (arrow) 1 year after clip implantation. 4D-DVT pathline imaging showing eccentric swirling mitral regurgitation jets reaching the posterior left atrium due to mitral valve prolapse. Follow-up cardiovascular magnetic resonance at 1 year. Reduced mitral regurgitation volume was observed by 4D-DVT imaging, which allowed volumetric quantification above the mitral annulus even after MitraClip implantation. Supplementary material is available at European Heart Journal – Case Reports online. Consent: The study was approved by the local research ethics board and written informed consent was obtained from the parent. Funding: This work was supported in part by Japan Society for Promotion of Science (grant number 18K08106).
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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".