This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for The REVEALPLAQUE Study: A pRospEctiVe, multicEnter Study to AnaLyze PLAQUE Using CCTA (NCT05138289), a registered phase not stated study. The primary outcome is Comparison of Total Plaque Volume.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05138289 |
| Phase | Phase not stated |
| Condition | Coronary Artery Disease (CAD) (E.G., Angina, Myocardial Infarction, and Atherosclerotic Heart Disease (ASHD)) |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 258 |
| Arms in the primary outcome | n/a |
| Lead sponsor | HeartFlow, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
The registry lists coronary artery disease, including angina, myocardial infarction, and atherosclerotic heart disease. It records enrollment of 258 participants. Specific eligibility criteria and the characteristics of the analyzed population are not reported in the registry record.
Intervention
The method under evaluation is AI-QCPA, an artificial intelligence quantitative coronary plaque analysis using CCTA. The study description concerns quantification and characterization of coronary atherosclerosis with this noninvasive imaging approach.
Comparator
The comparison method is IVUS, or intravascular ultrasound. The registry describes a comparison of measurements from AI-QCPA and IVUS; this is a method-comparison question, not a treatment-versus-control question.
Primary question
The primary endpoint is the Pearson correlation statistic for total plaque volume measured by AI-QCPA and IVUS. The central question is how closely the two methods’ measurements vary together. The numerical correlation result is not reported in the registry record.
In statistical terms, the study asks whether measurements from a noninvasive imaging analysis are associated with measurements from an invasive imaging method. That is narrower than asking whether the methods give interchangeable values. Correlation describes how measurements change together; agreement also concerns whether the values themselves are sufficiently similar. A correlation estimate, considered alone, cannot answer every question about agreement or establish the accuracy of either method. The record’s description uses the language of agreement, while its named primary statistic is Pearson’s correlation. No numerical estimate, confidence interval, or test result is reported, so the strength and precision of the observed relationship cannot be assessed from the registry record.
3. Trial Design
REVEALPLAQUE is described in its title as a prospective, multicenter study. Its stated purpose is to evaluate agreement between CCTA-based quantification and characterization of coronary atherosclerosis and invasive IVUS. The registry lists HeartFlow, Inc. as the sponsor and reports enrollment of 258 participants. The study status is completed.
The registry records a start date of 2021-10-12 and a primary completion date of 2022-11-08. The primary outcome timeframe is listed as 13 months. These dates and the stated timeframe provide registry context, but they do not establish when each participant was imaged or when individual measurements were made.
The comparison concerns two measurement approaches rather than randomized treatment groups. Allocation is not stated, and the registry explicitly cautions that arms are not a like-for-like control comparison. Consequently, descriptions used for randomized treatment trials—such as treatment assignment, a control arm, or a between-arm treatment effect—do not characterize the primary question recorded for this study.
The primary outcome is comparison of total plaque volume, expressed as a Pearson correlation statistic. The registry also notes that the baseline participant count differs from participant flow because 21 participants were excluded from analysis owing to technical limitations and inability to process medical imaging data. The number included in the primary analysis is not reported in the registry record, and it should not be inferred by subtracting exclusions from enrollment. Eligibility criteria, site counts, imaging acquisition details, and the statistical analysis plan are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | IVUS |
|---|---|
| STARTED | 258 |
| COMPLETED | 258 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Baseline participants is not the same as the Participant flow as 21 participants were excluded from analysis due to technical limitations and we were not able to process medical imaging data.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: Baseline participants is not the same as the Participant flow as 21 participants were excluded from analysis due to technical limitations and we were not able to process medical imaging data.
| Characteristic | Unit | IVUS |
|---|---|---|
| Participants analysed | 237 | |
| Age, Continuous | years | 67.5 (SD 9.8) |
| Sex: Female, Male: Female | Participants | 61 |
| Sex: Female, Male: Male | Participants | 176 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 9 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 227 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 1 |
| Race/Ethnicity, Customized: Race – White | Participants | 157 |
| Race/Ethnicity, Customized: Race – Black or African American | Participants | 9 |
| Race/Ethnicity, Customized: Race – Asian | Participants | 63 |
| Race/Ethnicity, Customized: Race – American Indian or Alaska Native | Participants | 0 |
| Race/Ethnicity, Customized: Race – Native Hawaiian or other Pacific Islander | Participants | 0 |
| Race/Ethnicity, Customized: Race – Other | Participants | 8 |
6. Primary Endpoint
The registry lists the primary outcome as Comparison of Total Plaque Volume, measured over 13 months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Pearson's correlation statistic |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint concerns the relationship between total plaque volume measured by AI-QCPA and total plaque volume measured by IVUS. Its reported unit is Pearson’s correlation statistic, and the timeframe is listed as 13 months. The registry’s outcome description frames the purpose as assessing the level of agreement between the methods.
As a general statistical concept, Pearson’s correlation measures the direction and strength of a linear association between two quantitative measurements. A high correlation indicates that larger values from one measure tend to accompany larger values from the other, but it does not necessarily mean the measurements are numerically close. For example, a consistent systematic offset between methods can coexist with a strong correlation. Correlation may also be affected by the range of values in the participants being measured and by unusual observations.
For that reason, the named statistic provides information relevant to method comparison but is not, by itself, a complete assessment of interchangeability. Other approaches may examine differences between measurements, systematic bias, or the spread of those differences. Whether such analyses were planned or conducted is not reported in the registry record. The record does not report the Pearson correlation estimate, its confidence interval, a p-value, or the number of participants contributing to the endpoint. Thus, the endpoint’s definition is available, but its observed magnitude and precision cannot be evaluated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies total plaque volume as the primary outcome and names Pearson’s correlation as its statistic. However, it does not report an outcome estimate or a statistical analysis result. There is therefore no numerical correlation to interpret, and the direction, strength, and precision of the relationship between AI-QCPA and IVUS measurements cannot be determined from the registry record. A p-value, confidence interval, and analysis sample size are also not reported.
The distinction between correlation and agreement matters for interpreting the study question. In general, correlation describes whether two measurements vary together in a linear pattern. It does not establish that one method reproduces the numerical values of the other. Two methods could rank participants similarly while differing systematically in their measured values. Conversely, a restricted range of observed values can make correlation appear weaker even when the measurements are close. These are general properties of correlation, not claims about the results of REVEALPLAQUE.
The registry calls the primary outcome a comparison of total plaque volume and describes the goal as examining agreement. But the named statistic is Pearson’s correlation, and no additional agreement statistic is listed in the record. Without results for differences between methods or other agreement measures, the record does not establish whether values are interchangeable or whether either method has a particular degree of measurement error.
Participant flow also bears on interpretation. The registry says that 21 participants were excluded from analysis because of technical limitations and inability to process imaging data. It notes that the baseline participant count is not the same as participant flow, but does not report the final analysis count. Technical exclusions can affect which participants contribute to an imaging analysis. As a general consideration, if the ability to process images is related to participant or image characteristics, analyzed data may not represent all enrolled participants in the same way. The registry does not provide enough information to assess whether that occurred.
Enrollment of 258 is not the same as the number analyzed for the primary endpoint. No estimate should be treated as precise or generalizable without knowing the analysis population, the observed result, and its uncertainty. The record supports describing the study’s purpose and endpoint, but not concluding how closely the methods agreed or what the result implies about performance in other populations or settings.
9. Statistical Methods Explained
The statistical method named for the primary endpoint is Pearson’s correlation statistic. It is intended to summarize the linear association between two quantitative measurements—in this study, total plaque volume measured by AI-QCPA and by IVUS. The registry does not report a numerical estimate, confidence interval, p-value, or detailed analysis procedure, so the method can be explained conceptually but its implementation and result cannot be checked.
What does correlation describe?
As a general explanation, correlation summarizes whether values from two measures tend to increase or decrease together in a linear pattern. It is not a measure of the absolute difference between their values. If one method consistently reads higher than another, the measures may still be strongly correlated. Correlation therefore addresses association, while agreement asks whether the measurements are sufficiently close for the intended use. The distinction is important because the registry describes agreement but names correlation as its primary statistic.
Pearson’s correlation is most directly informative when a linear relationship is a reasonable summary of the paired measurements. It can be influenced by extreme observations and by how broadly measurements vary across the analyzed participants. These are general properties of the statistic; the registry record does not report diagnostic plots or other information that would establish whether they are concerns for this dataset. A single correlation value also does not reveal the nature of any systematic difference between methods.
What would uncertainty estimates add?
A confidence interval is a general statistical tool for expressing uncertainty around an estimated quantity. For a correlation, it would show the range of values reasonably compatible with the data under the method used to construct the interval. A p-value, if reported, would address a specified statistical hypothesis under its assumptions; it would not show the size or practical importance of an association. Neither a confidence interval nor a p-value is reported for the primary endpoint in the registry record. Without an estimate and its uncertainty, the statistical evidence cannot be evaluated for magnitude or precision.
The analysis sample size is also not reported. Although enrollment is 258, the registry states that 21 participants were excluded from analysis because of technical limitations and inability to process their imaging data. It does not state the number contributing measurements to the primary outcome. The enrollment count should not be substituted for the analyzed count, and the excluded participants should not be assumed to have contributed endpoint data.
How should planning illustrations be read?
General sample-size illustrations are planning calculations, not observed study findings. The described illustration framework uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. For time-to-event outcomes it describes total events; other illustrations are expressed as participants per arm. Those conventions do not establish the study’s original design assumptions, and the registry record does not report a trial-specific sample-size justification. The study’s primary question is a comparison of measurement methods, not a randomized treatment comparison, so equal allocation between treatment arms should not be read as a description of its design. Any planning illustration is not observed power and cannot supply a missing endpoint result.
What cannot be reconstructed from the record?
The registry lists one outcome measure and zero analyses. It does not report an analysis plan, the handling of repeated or unusable measurements, criteria for selecting observations, a method for assessing agreement beyond Pearson’s correlation, or procedures for uncertainty estimation. Nor does it report whether prespecified exclusions or sensitivity analyses were used. Those omissions prevent reconstruction of the statistical workflow or independent appraisal of analytic choices. They do not show that a method was or was not used; such details are simply not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure, the comparison of total plaque volume, and zero analyses. It does not report whether additional analyses were planned, which analyses were considered primary or secondary, or how multiple statistical tests would be handled. A multiplicity strategy is therefore not reported in the registry record. With no numerical analysis results listed, there is also no basis for assessing the impact of any unreported multiple testing.
Missing data and exclusions are relevant because the registry states that 21 participants were excluded from analysis owing to technical limitations and inability to process medical imaging data. It also says that the baseline participant count differs from participant flow. The final number included in the primary analysis, reasons for any other missing measurements, and methods for handling incomplete data are not reported in the registry record. The record does not say whether the excluded participants differed from those analyzed or whether exclusions were specified in advance.
As a general statistical consideration, excluding participants with unprocessable images can affect the population represented by the analysis if image processability is related to participant or imaging characteristics. That possibility cannot be assessed from the available record. No imputation approach, sensitivity analysis, or missing-data assumption is reported.
The record also does not define a detailed analysis population, such as criteria for inclusion in the primary endpoint analysis. Consequently, enrollment should not be interpreted as the endpoint denominator. A full account of multiplicity and missingness would require details on planned outcomes, analyses, participant disposition, and the treatment of unavailable measurements; those details are not reported in the registry record.
11. What the Result Does, and Does Not, Mean
The registry record establishes that REVEALPLAQUE was designed to compare total plaque volume measured with AI-QCPA using CCTA against total plaque volume measured with IVUS. It identifies Pearson’s correlation as the primary endpoint statistic and describes the broader aim as evaluating agreement between the methods. It also records enrollment of 258 participants and notes that 21 participants were excluded from analysis because their imaging data could not be processed owing to technical limitations.
The record does not report the correlation estimate, its uncertainty, a p-value, or the final endpoint analysis count. As a result, it does not show how strong the relationship was, how precisely it was estimated, or whether the two methods produced similar numerical values. The absence of a result in the registry record should not be interpreted as evidence for or against a particular degree of association or agreement.
More generally, correlation and agreement answer related but different questions. Correlation can describe whether measurements move together, but does not alone establish that the values are interchangeable. The registry does not report an additional agreement analysis that would address systematic differences or the distribution of measurement differences. No conclusion about interchangeability can therefore be drawn from the endpoint definition alone.
The study is not described as a randomized comparison of treatments. Its method-comparison purpose does not establish that one imaging approach improves health outcomes, changes clinical decisions, or is preferable for a particular person. The record also does not report enough information to determine how representative the analyzed participants were, given the technical exclusions. The appropriate statistical conclusion is limited: the study’s question and endpoint are described, but its observed result and precision are not reported in the registry record.
12. Why This Trial Matters Statistically
Method-comparison studies raise a statistical question that differs from the usual treatment comparison. They ask whether two ways of measuring a feature produce related or sufficiently similar values. REVEALPLAQUE focuses on total plaque volume measured by AI-QCPA using CCTA and by IVUS. Its primary endpoint makes the choice of statistical measure consequential: Pearson’s correlation describes linear association, whereas agreement concerns the closeness of the methods’ actual measurements.
This distinction matters because a correlation can be informative without proving that two methods are interchangeable. Readers need to know both what a statistic measures and what it leaves unanswered. A reported correlation, if available, would need to be considered alongside its uncertainty and any other analyses addressing agreement. The registry record does not report those results, so it cannot support an assessment of the size or precision of the relationship.
The recorded technical exclusions also illustrate why participant flow is part of statistical interpretation. The registry reports that 21 participants could not be analyzed because their imaging data could not be processed. When an endpoint depends on usable images, the analyzed population may differ from enrollment. The number analyzed and any assessment of the exclusions’ consequences are not reported in the registry record.
Finally, the study highlights the difference between describing a study question and evaluating its evidence. A prospective, multicenter design and an enrolled population provide context, but they do not substitute for the endpoint estimate, its uncertainty, or a transparent account of the analysis population. Statistical interpretation depends on those details, particularly when the stated aim uses the broad term agreement while the primary statistic is correlation.
13. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The most important limitation for interpreting the registry record is that it contains no numerical result for the primary endpoint. The Pearson correlation estimate, confidence interval, p-value, and analysis sample size are not reported. This prevents assessment of the association’s magnitude and precision and leaves the central method-comparison result unresolved.
The endpoint definition also limits what can be inferred. The study description refers to agreement, but the named statistic is Pearson’s correlation. Correlation does not by itself quantify systematic differences or establish that measurements are interchangeable. The registry does not list another agreement measure or provide results for differences between methods.
Participant flow is incompletely described. The record notes that 21 participants were excluded because of technical limitations and inability to process medical imaging data, and says that baseline participants do not match participant flow. It does not report the final analyzed count, additional details about image failures, or whether the exclusions may have affected the composition of the analyzed population.
Further methodological details are not reported in the registry record, including eligibility criteria, site counts, imaging and measurement procedures, the statistical analysis plan, multiplicity handling, missing-data methods, and sensitivity analyses. The registry describes the study as prospective and multicenter, but those labels do not resolve these analytic uncertainties. The available information supports a description of the study’s objective and endpoint, not a full appraisal of the analysis or the performance of either method.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: The REVEALPLAQUE Study: A pRospEctiVe, multicEnter Study to AnaLyze PLAQUE Using CCTA — NCT05138289.
- Registry record last updated 2025-08-22; status last verified 2025-08.
- Results first posted 2025-01-29.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
17. Record Summary
REVEALPLAQUE (NCT05138289) is a completed prospective, multicenter study sponsored by HeartFlow, Inc. It evaluates CCTA-based AI-QCPA measurement and characterization of coronary atherosclerosis against IVUS. The registry records enrollment of 258 participants, a start date of 2021-10-12, and a primary completion date of 2022-11-08.
The primary outcome is comparison of total plaque volume, expressed as a Pearson correlation statistic, with a timeframe listed as 13 months. The record notes that 21 participants were excluded from analysis because of technical limitations and inability to process imaging data. It lists one outcome measure and zero analyses.
The numerical primary outcome result, confidence interval, p-value, and final analysis count are not reported in the registry record. The registry describes an agreement question, but the named endpoint statistic measures correlation and does not alone establish interchangeability.