Virtual Spirometry: Running and Results

Research Use Only. Virtual Spirometry sits outside the declared intended use of the device. Its output is for study and investigation and must not be used to inform a diagnostic or therapeutic decision about an individual patient. See Intended Use and Safety.

Step 5: Run the Analysis

1. Review the patient data, the breathing mode and the scenario (No scenario for the patient’s baseline)
2. Press the round green start button

The job runs and its status is polled periodically while it computes. The panel updates when results are ready.

Step 6: Review Results

A run typically takes 3–5 minutes. When it completes, the report opens with:

• A flow–volume loop for the whole lung, plotted from the simulated cycle. Several runs can be overlaid on the same chart for comparison.
• FEV1 (L), FVC (L) and the FEV1/FVC ratio (%).
• A per-lobe table — FEV1, FVC, FEV1/FVC, each lobe’s share of total FVC, and volume share — for all five lobes.
• Left lung and right lung aggregate rows.
• A simulation conditions block recording the parameters actually used: whether the muscle-effort values came from the patient’s anthropometrics or from generic constants, and whether the run used the shipped model parameters or a set recalibrated on your own cohort (params_origin).

Why the parameter origin is recorded. The shipped model is tuned on our reference population. A site can have its own set fitted to its own patients, and once that set is in use every run on that site uses it. Two runs on the same patient — one before, one after a set was adopted — can therefore differ, and the conditions block is what tells you which of the two you are looking at. Recalibration can be run from the interface — see Recalibrating Virtual Spirometry on Your Cohort — but adopting its result is closed for now, so on a site that has never adopted a set this always reads shipped, which is today’s behaviour for everyone.

Metric	Meaning
FEV1	Forced expiratory volume in 1 second
FVC	Forced vital capacity
FEV1/FVC	Ratio conventionally used to flag obstruction

PEF is computed and stored with the result, but is not currently displayed.

These are simulated quantities. The model produces no reference values of its own — no percent-predicted, no z-scores, no LLN/ULN. Where you see Pred or %Pred columns beside a run, those come from a real spirometry report uploaded as a PDF, not from the simulation. Do not read the simulated numbers as a measurement of the patient.

Saving and Exporting

The analysis result is associated with the patient’s data once the job completes. Use Download XML in the panel to export the run.

Research Applications

Baseline reference

Running virtual spirometry on the baseline anatomy gives a reference point for comparison with a simulated post-resection configuration (see the next tutorial). Both are simulations, and the comparison describes the model, not the patient.

Longitudinal study

Running the analysis on serial scans lets you follow how simulated quantities change as the reconstructed anatomy changes over time.

Troubleshooting

The Analysis Does Not Start

• Check the anatomy: the lungs must be segmented and have a clean surface
• Check patient data: make sure the anthropometric inputs are filled in
• Re-open the panel from the lung analysis controls if it is not visible

Results Look Off

• Review the segmentation: under- or over-segmented lungs change the volumes
• Check the inputs: an incorrect height or gender shifts the model
• Check the scenario: a run with a scenario selected is a hypothesis, not the patient — compare it with a No scenario run

Best Practices

1. Segment airways when possible for a better lung model
2. Clean the lung surface before running
3. Enter accurate anthropometrics
4. Run the baseline first (No scenario), then any scenario to compare against it
5. Treat outputs as estimates and correlate with clinical data