LVOT cine imaging

LVOT cine imaging supports automated measurement of proximal aortic-root geometry. In CardiacNexus, this modality feeds the LVOT/aortic-root subset of Valvular and flow phenotypes.

Modality
LVOT cine CMR
UKB source
Data Field 20212
Pipeline step
Processed LVOT cine segmentation, accepted-frame diameter extraction, and LVOT QC overlays
Outputs
LVOT.csv / aortic_diameter feature folder; visualization/aorta/LVOT_*.png
Maturity
Source-audited modality page

Current pipeline role

The current implementation reads lvot_processed.nii.gz and seg_lvot.nii.gz. For each time frame that passes lvot_pass_quality_control, it derives three aortic-root landmarks from the segmentation: aortic valve annulus, aortic sinuses, and sinotubular junction. The final tabular rows use the median accepted-frame diameter for each level.

When BSA is available, the same source also emits BSA-indexed diameter rows. The phenotype page currently surfaces the three primary absolute diameter rows; the output inventory records the absolute and indexed rows as the broader LVOT contract.

Current outputs

Output familyCurrent rowsSource pathNotes
Aortic-root diametersLVOT: Aortic Valve Annulus Diameter [mm], LVOT: Aortic Sinuses Diameter [mm], LVOT: Sinotubular Junction Diameter [mm]src/feature_extraction/LVOT_20212/eval_LVOT.pymedian across accepted frames
BSA-indexed aortic-root diameterscorresponding /BSA [mm/m^2] rowseval_LVOT.py; query_BSAconditional on BSA availability
QC overlaysvisualization/aorta/LVOT_*.pngeval_LVOT.pyframe-level landmark overlays

QC and interpretation caveats

LVOT measurements depend on plane prescription, segmentation quality, landmark geometry, and accepted-frame availability. The source skips frames that fail LVOT QC, skips geometrically implausible corner detection, and warns when sinus diameter is not larger than annulus or sinotubular junction. If BSA lookup fails, indexed rows are not produced for that subject.

LVOT diameters should be interpreted with phase-contrast flow and aortic-structure context when valve physiology or aortopathy is relevant. They are geometric measurements, not diagnostic valve-disease classifiers.

Source audit

  • Current input names, QC behavior, landmark logic, output labels, BSA-indexed rows, and visualization paths were checked against eval_LVOT.py.
  • docs/data/output_column_inventory.yml records the broader LVOT artifact contract.
  • Textbook context boundary: broad clinical textbook context is not surfaced here because the source implementation and phenotype page provide enough page-specific context for draft rollout.
Aortic-root and LVOT anatomy context from the CardiacNexus manuscript image cache
Aortic-root anatomy context from the manuscript image cache, cited there to Hacking 2024, shown to orient LVOT cine root and annular measurement outputs. CardiacNexus root, annular, and valve rows remain implementation-defined and require linked output tables for interpretation.Source: manuscript image cache citing Hacking 2024; permission and exact reuse wording pending for draft use.
  • Displayed figure provenance is recorded in docs/data/figure_provenance.yml; permission and exact reuse wording remain pending for public release.