Patterns and Prevalence of FDG Extravasation in PET/CT Scans: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Patterns and Prevalence of FDG Extravasation in PET/CT Scans (NCT03041090), a non-randomized na study. The primary outcome is Number of Participants With Intraveneous Infiltration of FDG During Routine PET/CT Imaging by Visually Assessment of Interpreting Physicians.

2. Clinical Question

3. Trial Design

This completed study examined FDG extravasation or infiltration in the setting of PET/CT imaging. The registry lists an enrollment of 133 and identifies the condition as intravenous infiltration. The study ran from 2016-03 to primary completion in 2017-12. It was sponsored by St. Louis University.

The design is listed as nonrandomized, with parallel groups and no masking. Participants were assessed in a static-imaging group or a dynamic-imaging group. The static group used standard-of-care images obtained after the standard-of-care uptake time. The dynamic group used study-related images of and around the injection site acquired during the standard-of-care uptake period. In each group, images were described as assessed visually by a board-certified physician and using time activity curves from sensor data.

The intervention is named the Lucerno ID System. The study description explains that sensors can capture time activity curves during tracer uptake, and that these curves may help identify tracer presence near an injection site. It also describes the study objective as determining whether time activity curves correspond to PET images of the injection site taken during uptake. The registry lists a measurement period from sensor placement to removal, no more than 2 hours.

The registry does not describe random assignment, allocation concealment, or masking; masking is listed as none. Because the groups were not randomized and differ in imaging approach, group comparisons cannot automatically be interpreted as causal effects of one approach versus another. Detailed eligibility criteria and participant characteristics are not reported in the registry record. The study phase is listed as NA.

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

Reasons for not completing this period:

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: Data were analyzed by physician review of the static standard of care PET/CT images and dynamic injection site images for visible evidence of radiotracer infiltration. The Time Activity Curves (TACs) generated from the applied sensors were independently assessed and the results compared to physician assessments of the PET/CT images.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Intraveneous Infiltration of FDG During Routine PET/CT Imaging by Visually Assessment of Interpreting Physicians, measured over The time frame would be from the time the sensors were placed to the time the sensors were removed; no more than 2 hours..

The primary endpoint is the number of participants with FDG intravenous infiltration during routine PET/CT imaging, identified by visual assessment of interpreting physicians. It is a count of participants, rather than a measure of the amount of tracer at the injection site or a measure of image quality. The stated timeframe runs from sensor placement to sensor removal, for no more than 2 hours.

The endpoint addresses whether physicians identify radiotracer presence near the injection site. This matters to the study question because the registry description notes that an injection site may not appear in routine images, potentially leaving a reading physician unaware of an infiltration. The study aimed to compare rates of radiotracer presence near the injection site detected by physicians and to examine whether sensor time activity curves correspond to PET images of that site.

As a count, the endpoint needs a clearly defined assessment rule and an account of how many participants were evaluated. The registry record does not report the primary endpoint counts, the number assessed for the primary endpoint, or the detailed criteria physicians used to classify infiltration. It therefore does not show the observed frequency or allow the precision of that frequency to be evaluated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General: The study addresses a detection question. A participant is classified according to whether infiltration is identified, so the endpoint is binary at the participant level; the primary measure is the count of participants classified as having infiltration. A count by itself does not tell the reader how common the event was unless the number assessed is also known. A proportion can communicate frequency, while an interval around that proportion communicates uncertainty. The registry record does not report the primary outcome count, denominator, or interval.

What does a nonrandomized parallel design imply?

The registry lists nonrandomized allocation and a parallel model. In a parallel design, groups are assessed separately rather than each participant necessarily receiving every study approach. Here, the listed groups are static imaging and dynamic imaging. Since assignment was not randomized, differences between groups may reflect participant or study-process differences as well as imaging approach. Randomization is a general method for balancing measured and unmeasured factors across groups on average; it is not reported for this study. The record also lists no masking. The available details do not state whether image readers knew the group or sensor information, so the potential for assessment awareness cannot be evaluated further.

The descriptions say that images were assessed visually by a board-certified physician and using sensor time activity curves. These are different forms of information, and a comparison between them depends on how each is defined and aligned. For example, a diagnostic agreement analysis would ordinarily specify which assessment is treated as the reference and how discordant classifications are handled. Those details and the resulting agreement statistics are not reported in the registry record. The study’s secondary outcomes mention sensor detection and physician identification, but outcome names alone do not define a full analysis method.

Why do counts and denominators matter?

General: For an event outcome, the count describes the number of observed events, while the denominator describes the number of participants whose outcome could be assessed. Both are needed to interpret an event frequency. If some participants have no usable assessment, the denominator can depend on how missing outcomes are handled. The primary endpoint is specified as a count of participants, but the posted results do not state the relevant counts or denominators. The safety results list participants at risk for adverse-event reporting, but those figures are not a substitute for the primary endpoint denominator unless the registry explicitly establishes that they are the same analysis population.

General: A confidence interval expresses sampling uncertainty around an estimate, conditional on the model and data used. A narrow interval generally indicates more precision than a wide interval, but precision does not eliminate bias from a nonrandomized design, incomplete assessment, or outcome misclassification. No primary endpoint confidence interval is reported in the registry record. There is also no reported model, adjustment set, or inferential comparison for that endpoint.

How should planning calculations be read?

The registry’s sample-size assumptions describe planning illustrations using a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect expressed as a stated fraction of the observed effect. These are planning illustrations, not observed power. They are not evidence that the study was designed with a particular power, and they should not be interpreted as a post hoc measure of success. The trial’s own sample-size justification is not reported in the registry record. The posted primary event counts and effect estimate are also not reported, so readers cannot inspect the observed effect that the planning approach references.

General: Power is a design concept describing the chance that a planned analysis will detect a specified effect if that effect is present, under the assumed design and model. Power depends on assumptions about event frequency, effect size, variability, allocation, and the analysis. A planning calculation is useful only in relation to those assumptions; changing the assumed effect changes the resulting planning requirement. It does not show whether a completed study found an effect. In this study, no trial-specific power justification or inferential analysis is reported in the registry record.

General: For binary outcomes, methods may compare event proportions or model the probability of an event. A valid analysis also needs to account for the study design and the way participants entered each group. Adjustment can sometimes address measured differences, but it cannot guarantee removal of bias from unmeasured factors. The registry record does not report a primary-outcome model or covariate adjustment, so no particular method should be attributed to the investigators.

The outcome timeframe is defined in relation to sensor placement and removal, no more than 2 hours. That defines a period for the endpoint assessment, but the record does not report timing distributions, adherence to that period, or whether all participants had complete assessments within it. Those details would be useful for understanding the consistency of outcome ascertainment. Overall, the design and endpoint description identify what the study intended to examine, while the missing outcome counts and analysis details limit statistical interpretation of the results.

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("Dynamic Arm", "Static Arm")
n      <- c(21, 109)
events <- c(17, 32)
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  Dynamic Arm  21  17  81.0  58.1  94.6  60.0  92.3  59.7  92.2
ARM  Static Arm  109  32  29.4  21.0  38.8  21.6  38.5  21.6  38.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and secondary outcomes concerning sensor-detected infiltration and the percentage of participants with infiltrations identified by physicians and the sensor device. It does not report a statistical analysis plan describing how these outcomes were prioritized, whether hypotheses were prespecified, or how multiplicity was addressed. Multiplicity is a general concern when several outcomes or comparisons are tested: the chance of obtaining at least one apparently unusual result can increase as the number of tests increases. No correction method or testing hierarchy is reported in the registry record, so the treatment of multiple outcomes cannot be assessed.

Missing-data methods are not reported in the registry record. The record does not state how many participants had complete physician assessments, sensor readings, or image evaluations; whether any outcomes were unavailable; or how unavailable assessments would be handled. It also does not report exclusions from an endpoint analysis or sensitivity analyses for missing observations. Absence of a missing-data description should not be interpreted as evidence that no data were missing.

Analysis populations are also not described. The record does not specify whether the primary endpoint included every enrolled participant, only participants with evaluable images, or another defined group. This matters because the count and denominator must refer to a clearly defined population. Although safety results list participants at risk in the dynamic and static groups, the registry does not state that those populations are the same as the endpoint analysis populations.

No statistical analyses are listed in the registry record. Consequently, the analysis populations, handling of missingness, multiplicity strategy, and any deviations from a planned analysis cannot be evaluated from the 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 0% reporting threshold.

The registry’s adverse-event figures list the dynamic group with 24 participants at risk and 0 serious adverse events, 0 other adverse events, and 0 deaths. The static group lists 109 participants at risk and 0 serious adverse events, 0 other adverse events, and 0 deaths. These are the safety figures recorded for the groups; they are not results for the primary infiltration endpoint.

A zero in these fields means that no events of that category are recorded for the corresponding group in this registry entry. It does not establish that the study’s observation process would identify every possible event, nor does it show that no event could occur outside the recorded period or reporting definitions. The safety reporting timeframe and detailed adverse-event collection procedures are not reported in the registry record.

These figures should also be read in light of the study’s nonrandomized design and the listed at-risk populations. They do not provide a randomized comparison of safety, and the registry does not report an analysis comparing groups. No serious adverse-event terms are listed. The absence of reported events is a description of the registry record, not a general conclusion about safety.

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

The study is relevant to a practical imaging problem described in its registry summary: an injection-site infiltration may be difficult to recognize when the injection site is not included in routine images. It examined whether sensor time activity curves correspond to PET images of the injection site and described physician review of static and dynamic imaging. This makes the study question one of detection and assessment, rather than a treatment comparison.

The posted record does not report the primary endpoint counts or the secondary outcome results. It therefore does not establish how frequently physicians identified infiltration in the study, whether sensor information identified it, or whether physician and sensor assessments agreed. It also does not provide estimates of uncertainty or a statistical comparison between the groups. No conclusion about the size or precision of an observed detection difference can be drawn from the record.

Even if group-specific results were available, the nonrandomized allocation would require caution in interpreting differences. The static and dynamic groups had different imaging approaches, and the registry does not report enough information about group comparability or adjusted analyses to separate the imaging approach from other potential differences. The record lists no masking, and does not specify reader awareness or detailed assessment procedures.

The safety figures describe zero recorded adverse events in the listed categories for the groups, but they do not answer the primary question about infiltration detection. The registry’s background estimate of approximately 15% is not the study’s observed event rate. Overall, the registry describes a completed investigation and its intended assessments, but its posted outcome information is insufficient to quantify the primary finding or its statistical uncertainty.

14. Why This Trial Matters Statistically

This study illustrates why an endpoint’s definition and the way it is measured matter. The stated primary outcome is a count of participants with physician-identified infiltration. That is not interchangeable with sensor detection, visual findings on dynamic images, or agreement between assessment methods. Each answers a related but distinct question. Clear outcome definitions and reported counts are needed to show what was observed.

The study also highlights the difference between a detection objective and a causal comparison. Its groups used different imaging approaches, but allocation was nonrandomized. A difference between groups, if available, could not be attributed to imaging approach alone without considering how participants entered the groups and whether other relevant characteristics differed. The registry does not report information that would resolve those issues.

From a statistical perspective, a count without its analysis denominator and uncertainty is difficult to interpret. A reported event frequency and confidence interval would help readers understand both the observed scale and its precision. The record does not report the primary counts or interval estimates, so the central statistical question remains unanswered in the posted results.

The planned use of sensor time activity curves also raises a general measurement question: whether a new signal corresponds to an established image-based assessment, and how disagreement is evaluated. The registry names related secondary outcomes but does not post their results or the analysis details. This record therefore helps identify the methodological questions that matter—endpoint ascertainment, agreement, group comparability, and precision—while leaving their empirical answers unreported.

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.

A key limitation of the registry record is that it does not report the primary endpoint results. The number of physician-identified infiltrations, the endpoint denominators, and any interval estimates or statistical tests are not available. The secondary outcomes are listed without numerical results. This prevents assessment of event frequency, sensor-physician agreement, or comparative precision.

The nonrandomized design limits interpretation of any potential group contrast. The static and dynamic groups differ in imaging approach, and the registry does not describe how participants were assigned or provide participant characteristics that could show whether the groups were comparable. No adjusted analysis is reported. The record also lists no masking, while the reader’s awareness of group or sensor information is not specified.

Outcome assessment details are limited. The primary endpoint is described as visual assessment by interpreting physicians, but detailed classification criteria, reader procedures, and handling of uncertain findings are not reported in the registry record. The registry does not explain how sensor readings were translated into a presence-or-absence classification or how disagreements between methods were analyzed.

Eligibility criteria, participant characteristics, missing-data procedures, analysis populations, multiplicity handling, and the trial’s own sample-size justification are not reported in the registry record. These omissions restrict evaluation of generalizability, potential selection effects, and the robustness of any statistical analysis. The brief summary supplies background context, but that context does not replace study-specific outcome results.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Patterns and Prevalence of FDG Extravasation in PET/CT Scans — NCT03041090.
• Registry record last updated 2019-06-14; status last verified 2019-06.
• Results first posted 2019-06-14.
• 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

NCT03041090 is a completed, nonrandomized parallel study sponsored by St. Louis University. The record lists enrollment of 133, a study start of 2016-03, and primary completion in 2017-12. The study examined FDG infiltration during PET/CT imaging using static and dynamic imaging groups, with the Lucerno ID System listed as the intervention.

The primary outcome was the count of participants with physician-identified FDG intravenous infiltration during routine PET/CT imaging. Secondary outcomes concerned sensor-detected infiltration and identification by physicians and the sensor device. The registry does not report numerical results for these outcomes or statistical analyses. Safety figures list 0 serious adverse events, 0 other adverse events, and 0 deaths for each group. The record does not report the trial’s sample-size justification, analysis populations, missing-data methods, or multiplicity approach.