Every clinical trial sponsor asks the same question before partnering with a core lab: Can we trust the numbers this lab produces?
Data quality is not an abstract concept. It determines whether a medical device gets approved, whether a novel therapeutic demonstrates true efficacy, and whether years of capital investment translate into a defensible regulatory submission.
We conducted an internal analysis that speaks directly to this question.
In echocardiography, hemodynamic parameters are measured using two primary forms of spectral Doppler: continuous wave (CW) and pulsed wave (PW). Both are standard, widely accepted techniques, but they work differently, so the choice of method depends on what exactly is being measured.
Because CW integrates velocity across the entire ultrasound beam, it captures the true peak velocity wherever it occurs along that path. PW, by design, only records velocity at the depth the operator selects, so it will underestimate the peak whenever the true peak lies outside that sample volume, which is the mechanical reason the two techniques do not agree.
When measurements intended for CW are inadvertently taken using PW (or vice versa), or when a technique is applied outside its intended location, it can result in severe diagnostic misclassification, such as falsely indicating stenosis in a valve that is actually normal.
Selecting the wrong technique, or failing to standardize protocol selection across trial sites, can quietly introduce systematic bias into a study’s endpoint data. Clinical guidelines call for CW when assessing peak RVOT gradients precisely because PW is prone to aliasing and underestimation at the high velocities that obstruction produces, creating a systematic, directional error rather than incidental noise. The question we set out to answer was: What is the magnitude of bias in RVOT metrics between CW and PW Doppler?
We analyzed 21 subjects, pairing CW and PW measurements for four key Right Ventricular Outflow Tract (RVOT) metrics: velocity time integral (VTI), peak velocity, peak pressure gradient, and mean pressure gradient. The pattern was consistent, statistically decisive, and revealed a systematic discrepancy.
Table 1. CW vs. PW Doppler means across four RVOT metrics (n=21 paired subjects).
Metric | CW Mean | PW Mean | Difference |
RVOT VTI (cm) | 42.41 | 23.92 | 18.49 |
RVOT Peak Velocity (m/s) | 1.96 | 1.13 | 0.83 |
RVOT Peak Pressure Gradient (mmHg) | 16.62 | 5.80 | 10.82 |
RVOT Mean Pressure Gradient (mmHg) | 9.25 | 2.98 | 6.27 |
This analysis illustrates a core principle: we do not assume a methodology is neutral. We test it, quantify it, and standardize it before it becomes an uncontrolled variable that undermines study conclusions.
For a sponsor evaluating research partners, that principle is the actual product. A core lab that proactively catches systematic bias in standard imaging techniques is a core lab that will identify protocol flaws before they reach a regulatory reviewer. It is the difference between an imaging vendor that executes instructions blindly and a scientific partner that understands what the numbers mean.
We approach every data set that comes through our lab with the conviction that methodology deserves the same scrutiny as the scientific hypothesis itself.
If you are evaluating research partners for an upcoming echo-based trial, cardiovascular therapeutic study, or structural heart device trial, we welcome the conversation. Let’s ensure your imaging endpoints are built on unassailable scientific rigor.
Cara Bergeron, MS, RDCS, RVT, FASE
Cara Bergeron, MS, RDCS, RVT, FASE, is the Echo Programs Manager at Medical Metrics, where she leads echocardiography core lab programs for cardiovascular and structural heart trials. A registered cardiac and vascular sonographer and Fellow of the American Society of Echocardiography, Cara focuses on keeping imaging methods rigorous and standardized from the first scan to the final endpoint.
