Stress CT Perfusion in Patients With Chest Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Stress CT Perfusion in Patients With Chest Pain (NCT01969916), a na na study. The primary outcome is Number of Participants With Detected Stress-induced Perfusion Abnormalities by 3D Analysis of MDCT Images.

2. Clinical Question

These details frame a diagnostic-imaging question rather than a randomized comparison of regadenoson against another treatment. The recorded outcome is a participant count, not a direct estimate of sensitivity, specificity, agreement with fractional flow reserve, or prediction accuracy. Those quantities require appropriately defined comparisons and results. Although the study description identifies comparison with invasive fractional flow reserve as a goal, the registry record does not report the corresponding analysis or its findings. It also does not report whether all enrolled participants underwent each imaging or invasive assessment. Accordingly, the record establishes the intended clinical question and design, but does not establish how well the imaging approach identified stenosis or predicted later outcomes.

3. Trial Design

The registry describes a completed, single-group study titled Stress CT Perfusion in Patients With Chest Pain. Its official title describes a comprehensive evaluation of patients with chest pain using cardiac computed tomography and asks about adding regadenoson stress perfusion imaging to noninvasive coronary angiography. The sponsor is the University of Chicago. The listed enrollment is 150, and the condition is coronary artery disease. The study start is recorded as 2014-06 and primary completion as 2018-06. Phase is listed as NA, allocation as NA, masking as none, and overall status as completed.

Regadenoson is the named intervention. The record does not describe a separate control arm, and its single-group designation means the posted design is not a randomized, like-for-like comparison between assigned groups. The study description says that stress MDCT perfusion data would be compared with invasive fractional flow reserve data among patients with significant stenosis who undergo invasive coronary angiography. It also describes a goal of assessing the added value of MDCT perfusion as an adjunct to CT coronary angiography for predicting patient outcomes. These statements describe the study aims; they do not substitute for results of those comparisons.

Important design details are not reported in the registry record. These include eligibility criteria beyond the stated clinical context, how participants were recruited, the specific imaging protocol, the regadenoson administration procedure, the criteria for undergoing invasive angiography, and the timing and methods for outcome follow-up. The arm description contains no additional detail. The record therefore supports a broad description of a completed single-group imaging study, but not a detailed reconstruction of its conduct. It does not report a control condition that would allow a causal comparison of assigned treatments, nor does it provide enough detail to assess how selection into imaging or invasive assessment may have shaped the results.

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

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Detected Stress-induced Perfusion Abnormalities by 3D Analysis of MDCT Images, measured over At least 1 year.

The registered primary endpoint is the number of participants with stress-induced perfusion abnormalities detected by three-dimensional analysis of MDCT images. The endpoint description specifies a perfusion defect on stress CT images obtained at peak effect of regadenoson, in the presence of coronary stenosis >50%. Its timeframe is listed as at least 1 year. This is a count of participants meeting the stated finding, not a measurement of the size or severity of each defect.

A participant count can describe how often the specified imaging finding was recorded in the studied group. That makes it a direct way to report the occurrence of the defined finding, but the count alone does not show whether CT identified all participants with stenosis, whether it produced false-positive findings, or how closely it agreed with invasive fractional flow reserve. Those questions need comparison data and a defined analysis. The study description identifies fractional flow reserve and clinical outcome prediction as broader aims, but the registry record does not report results for those aims.

The primary endpoint result itself is not reported in the registry record. The record therefore states what was intended to be counted but does not state the observed number of participants with the finding. It also does not report the analysis population, handling of unavailable scans, or a confidence interval for the endpoint. Without those details, the endpoint definition can be interpreted, but its observed frequency and precision cannot be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a participant-count endpoint and a single-group design, but it does not report an analysis plan for the primary outcome. Understanding what the listed endpoint can answer therefore requires separating the outcome definition from general statistical principles and from analyses that would need additional results.

What a participant count describes

General statistical explanation: a count records how many people meet a stated condition. In this study, the condition is a stress CT perfusion defect detected by three-dimensional MDCT analysis in the presence of coronary stenosis >50%. A count is easy to interpret as an observed number, but a count alone does not describe its uncertainty or its relationship to a reference test. To estimate a frequency, the relevant denominator must also be clear: for example, whether it includes all enrolled participants or only those with evaluable images and the relevant stenosis information. The analysis population and denominator are not reported in the registry record.

Precision and confidence intervals

General statistical explanation: a confidence interval expresses uncertainty around an estimated quantity, such as a proportion or a difference, under a specified statistical method. A narrower interval indicates greater precision under that method, while a wider interval indicates less precision. The interval depends on the observed data and on assumptions about how those data were generated. The registry does not report a confidence interval for the primary endpoint, nor does it report the endpoint count needed to interpret such an interval. No interval should be inferred from the enrollment figure alone.

For a binary finding, analysts may report the number meeting the endpoint together with the relevant denominator and an interval for the corresponding frequency. If the purpose is to compare an imaging result with a reference standard, the analysis must also define how each participant is classified by both methods. General statistical explanation: sensitivity and specificity use different conditional denominators, and agreement measures answer a different question from the raw frequency of a positive finding. The study description mentions invasive fractional flow reserve, but the registry record does not report a cross-classification of CT findings and fractional flow reserve results or any accuracy estimate.

Comparison and design

The study is recorded as single-group, with allocation listed as NA and masking as none. General statistical explanation: random allocation can make groups more comparable with respect to measured and unmeasured characteristics on average, whereas a single-group design does not create a randomized concurrent treatment contrast. A comparison between imaging methods within participants can still be scientifically informative, but it needs a prespecified paired analysis, clear reference criteria, and complete reporting of the paired observations. The registry describes a comparison with fractional flow reserve as a goal; it does not report the method or results of that comparison.

The study description also refers to predicting patient outcomes and to the added value of MDCT perfusion alongside CT coronary angiography. General statistical explanation: a prediction analysis needs a defined outcome, a follow-up period, a model or other prediction rule, and an assessment of how well predictions correspond to observed outcomes. Assessing added value requires a defined baseline approach and a stated measure of improvement. The primary endpoint description is a participant count for imaging abnormalities, while the registry does not report an outcome-prediction model, its performance, or the results of an added-value analysis.

Planning illustrations and observed results

The sample-size assumptions describe planning illustrations based on an observed effect, not the study’s own design justification. Those illustrations assume 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 stated fraction of the observed effect. The assumptions specify total events for time-to-event illustrations using the Schoenfeld approach and participants per arm for other illustrations. The actual study is recorded as single-group, so the equal-allocation framework does not describe its listed design. The registry record does not report the study’s sample-size justification or the calculations used when planning enrollment. Any planning illustration is not observed power and should not be read as proof that the completed study had adequate precision.

General statistical explanation: power is a planning probability defined under assumptions about a true effect, variability, analysis, and significance threshold. It is not a measure of whether a completed study’s result is reliable. After data are observed, interpretation should focus on the estimate, its uncertainty, the analysis assumptions, and the study design. Because the primary result and its uncertainty are not reported in the registry record, those features cannot be evaluated for this endpoint.

Multiplicity and model assumptions

The record lists one outcome measure and no analyses. This does not establish whether investigators considered additional endpoints, subgroups, or repeated testing in the full study. General statistical explanation: when many hypotheses are tested, the chance of at least one apparently unusual result can increase, so a statistical plan may define a primary comparison or address multiplicity. Whether any adjustment was planned or used is not reported in the registry record. The record also does not report whether the endpoint was analyzed as a count, a binary participant-level finding, or another form beyond the count wording in its definition.

General statistical explanation: model assumptions matter because estimates and intervals are trustworthy only to the extent that the method fits the data and design. A normal approximation, for example, is an assumption in the planning illustrations, not evidence that a particular endpoint analysis used that method. No primary-outcome model, test, adjustment, or diagnostic assessment is reported in the registry record. Statistical interpretation should therefore stop short of assigning a method or inferential conclusion that the record does not state.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Regadenoson")
n      <- c(150)
events <- c(56)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Regadenoson  150  56  37.3  29.6  45.6  30.0  45.3  30.0  45.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and zero analyses. The outcome measure is the count of participants with detected stress-induced perfusion abnormalities by three-dimensional MDCT analysis. The record does not report a statistical analysis plan, a hierarchy of primary and secondary hypotheses, or whether additional outcomes or subgroup analyses were considered. It also does not report a multiplicity adjustment. The absence of registered analysis details does not establish that no additional analyses occurred; it means their methods and results are not reported in the registry record.

General statistical explanation: multiplicity arises when several hypotheses or outcomes are evaluated. Without a prespecified plan, it can be difficult to distinguish a confirmatory finding from an exploratory one. An analysis plan can identify the principal endpoint, define other analyses as secondary or exploratory, and state whether and how error rates are controlled. The registry information does not allow readers to determine whether such decisions were made for this study.

Missing-data methods and analysis populations are also not reported in the registry record. The record does not state how many participants had interpretable stress CT images, whether all enrolled participants were assessed for the primary endpoint, how missing or indeterminate imaging was handled, or which participants contributed to any analysis. It does not report exclusions, withdrawals, or the completeness of follow-up for the stated timeframe of at least 1 year.

General statistical explanation: missing observations can affect an estimate when the participants with observed data differ in meaningful ways from those without observed data. The direction and size of any effect depend on the pattern and reason for missingness and on the analysis method. Without the relevant participant flow, missingness details, and analysis population, the completeness and potential representativeness of the endpoint data cannot be assessed. No particular missing-data mechanism or method should be assumed from the registry record.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The safety record lists 150 participants at risk for other adverse events, with 48 affected. It lists 0 participants at risk of serious adverse events with a serious adverse event, and 0 deaths. These are the recorded counts for the Regadenoson group. They should be read as registry entries, not as a comparison of regadenoson with another group, because no control group is listed.

The record does not list serious adverse-event terms. It also does not identify the types, severity, timing, duration, or attribution of the 48 other adverse events. The distinction between serious and other adverse events is part of the registry categorization; the recorded count of other adverse events does not by itself indicate their clinical importance or whether they were caused by the intervention. The record does not report how adverse events were collected or whether reporting was complete throughout follow-up.

General statistical explanation: safety counts are easier to interpret when the number at risk, follow-up time, event definitions, and ascertainment procedures are clear. A count from a single group cannot establish comparative risk, and a zero recorded count does not prove that an event is impossible. No comparative safety estimate or inference is reported in the registry record. The counts should therefore be treated as descriptive entries with limited information about event type and context.

13. What the Result Does, and Does Not, Mean

The registry establishes that a completed, single-group study was designed around regadenoson stress cardiac CT perfusion in patients with chest pain. It records a listed enrollment of 150 and defines a primary outcome based on whether a participant had a specified stress-induced perfusion abnormality. It also records adverse-event counts. These details are useful for understanding the intended question and the broad scope of the study.

The registry record does not report the observed result for the primary endpoint. It therefore does not show how many participants had the defined perfusion abnormality or the precision of any estimate of its frequency. It also does not report the proposed comparison with invasive fractional flow reserve or the analysis of added value alongside CT coronary angiography. The stated aim of predicting patient outcomes is not itself evidence that prediction was achieved; the corresponding data and analyses are not reported in the registry record.

The endpoint is not, on its own, a measure of diagnostic accuracy. A count of detected abnormalities does not reveal how many participants with a reference-standard finding were identified or how many without that finding had a positive imaging result. Nor does it establish whether imaging information predicts later outcomes. Those interpretations require results and methods that are absent from the registry information.

The adverse-event entries show 0 recorded serious adverse events and 0 deaths, alongside 48 participants affected by other adverse events among 150 at risk. They do not establish comparative safety or causation. Event descriptions and collection details are not reported in the registry record.

General statistical explanation: conclusions should match the design, endpoint, and uncertainty actually reported. A single-group study can describe observations within its participants, but without a suitable comparator it does not establish a treatment contrast. Without an endpoint estimate and uncertainty, it also cannot establish the magnitude or precision of the primary finding. The defensible interpretation is therefore that the registry records the study question and design, but leaves the main imaging result and the stated comparative and predictive aims unresolved.

14. Why This Trial Matters Statistically

This study is statistically interesting because its registry description brings together several distinct questions that can easily be conflated: whether stress CT detects a perfusion abnormality, whether that finding agrees with invasive fractional flow reserve, and whether the imaging adds useful information for predicting patient outcomes. Each question calls for its own clearly defined outcome and analysis. The registered primary endpoint is a participant count, while the broader aims include comparison and prediction. Keeping those targets separate is essential when interpreting a diagnostic-imaging study.

The single-group design also shapes the strength of possible conclusions. It can describe findings within the studied participants, but it does not provide a randomized concurrent control group for a treatment comparison. A within-participant comparison of imaging methods could address a different question, provided both methods and their results are reported. The registry describes such a comparison as a goal but does not report its analysis. The distinction between a design that can describe observed findings and an analysis that can establish agreement or prediction is central to sound statistical reading.

The record also illustrates why endpoint definitions and endpoint results must be distinguished. A precise definition identifies what was meant to count, including the specified CT finding and the presence of coronary stenosis >50%. But without the observed count, denominator, and uncertainty, readers cannot assess the frequency or precision of that finding. Likewise, an enrollment figure does not reveal how many participants had usable data for a particular analysis.

Finally, the lack of registered analysis details limits assessment of missing data, multiplicity, and model choices. These are not technical afterthoughts: they influence how much confidence readers can place in an estimate and whether a reported finding answers the intended question. The registry record’s limited results mean that statistical importance lies in recognizing both the carefully stated aims and the boundaries of what the posted information can support.

15. 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 of the registry information is that it defines the primary endpoint without reporting its observed result. The number of participants meeting the endpoint, the denominator used for analysis, and an uncertainty estimate are not reported in the registry record. As a result, the frequency and precision of the primary finding cannot be assessed from the record.

The design is recorded as single-group, with allocation listed as NA and no masking. No concurrent control group is described. This limits interpretation as a randomized comparison of treatment conditions and makes it important not to treat the study as if it had a like-for-like control arm. The study description refers to comparison with invasive fractional flow reserve and to outcome prediction, but the corresponding results and analysis details are not reported in the registry record.

Important operational details are also absent. The record does not report eligibility criteria in detail, the imaging protocol, regadenoson administration details, criteria for invasive angiography, participant flow, or the number with interpretable scans. It does not report how missing or indeterminate imaging findings were handled, which participants formed the analysis population, or how follow-up was completed for the stated timeframe of at least 1 year. These omissions prevent assessment of data completeness and the extent to which analyzed participants represent those enrolled.

The registry lists one outcome measure and zero analyses, but does not describe a statistical analysis plan, multiplicity procedures, or the method used to estimate the primary endpoint. It also does not report the study’s own sample-size justification. The planning assumptions describe illustrations based on observed effects and two-arm allocation, whereas the listed study design is single-group; those illustrations do not establish the design rationale or precision of the study’s primary result.

Safety interpretation is limited by the absence of adverse-event terms and details. The record gives counts but not the types, timing, severity beyond the serious-event category, attribution, or collection procedures for other adverse events. These limitations are specific to the information available in the registry record and should not be mistaken for evidence that the unreported procedures or analyses were not conducted.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Stress CT Perfusion in Patients With Chest Pain — NCT01969916.
• Registry record last updated 2021-02-21; status last verified 2021-02.
• Results first posted 2019-02-18.
• 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.

19. Record Summary

The registry describes a completed, single-group study of regadenoson stress CT perfusion in patients with chest pain, sponsored by the University of Chicago. The listed enrollment is 150; the condition is coronary artery disease. The record lists no masking, allocation as NA, and phase as NA. Its primary endpoint is a participant count for stress-induced perfusion abnormalities detected by three-dimensional MDCT analysis in the presence of coronary stenosis >50%, with a timeframe of at least 1 year.

The study description identifies comparison with invasive fractional flow reserve and assessment of added value for predicting outcomes as goals. The registry record does not report the primary endpoint result, analyses, or findings for those broader aims. It lists 0 participants with a serious adverse event, 48 participants with other adverse events among 150 at risk, and 0 deaths. Details of the other adverse events are not reported in the registry record.

Overall, the record establishes the study’s broad design, intended endpoint, and recorded adverse-event counts, but does not provide the endpoint estimate, uncertainty, analysis population, or statistical methods needed to assess imaging performance or outcome prediction.