Pilot Study Comparing Diagnostic Imaging Versus Tomosynthesis in Detection of Hip, Wrist or Tibia Injury: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pilot Study Comparing Diagnostic Imaging Versus Tomosynthesis in Detection of Hip, Wrist or Tibia Injury (NCT01927575), a non-randomized na study. The primary outcome is Number of Participants for Whom Tibia Injury Was Detected.

2. Clinical Question

The clinical question is therefore exploratory and focused on imaging assessment, rather than a reported estimate of diagnostic accuracy. The record describes a planned independent review by the principal investigator or designee. It does not report the review’s findings, a diagnostic reference standard, or participant-level classification results. It also does not report separate results for hip or wrist injury. Without the numerical primary outcome and details of how diagnoses were verified, readers cannot determine from this record how often tibia injury was detected or how TOMO compared with the other imaging procedures.

3. Trial Design

This was a pilot imaging study listed as terminated, with a non-randomized allocation and a crossover model. Masking was listed as none, and the phase was recorded as not applicable. Enrollment was 1. The registry lists a start date of 2013-09 and a primary completion date of 2014-04. The sponsor was Fujifilm Medical Systems USA, Inc.

The interventions included Standard X-Ray + CT, Standard X-Ray + MRI and TOMO. The comparative arm descriptions say that investigators would choose the standard of care for each subject. The record’s primary outcome population description refers to three tibia image sets: X-ray, CT and Digital Tomosynthesis. These descriptions establish that the study involved image comparisons, but they do not give a complete account of the imaging sequence or how every listed intervention related to the three image sets.

Non-randomized allocation means that assignment was not described as random. In general, random assignment is used to reduce systematic differences in the groups being compared; without it, comparison can be affected by how participants or procedures are selected. The registry record itself flags that the arms are not a like-for-like control comparison. The crossover label indicates a crossover model, but the sequence, timing and any washout arrangements are not reported in the registry record. Those details should not be inferred from the design label.

The stated aim was to build a library of image sets and assess whether TOMO could replace or complement current imaging standards for patients with hip, wrist or tibia injuries. The primary outcome was limited to the number of participants for whom tibia injury was detected at baseline imaging collection. No analysis results are listed, and no analysis is reported for the single registered outcome measure.

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.

Before assignment: Subjects are recruited as long as they had either an x-ray and CT or an x-ray and MRI, and sign a consent to have a third image taken with Fujifilm's Digital Radiographic AcSelerate CsI System with Tomosynthesis.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Three sets (1 - X-ray, 1- CT and 1 - Digital Tomosynthesis) of images of the tibia evaluated to confirm acceptable image quality and provided clinical and diagnostic value.

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: 1 patient was enrolled in this study, and they underwent Standard X-Ray and CT as well as Tomosynthesis.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants for Whom Tibia Injury Was Detected, measured over Baseline Imaging Collection.

The primary endpoint is titled “Number of Participants for Whom Tibia Injury Was Detected.” It is a count of participants, not a continuous measurement or a time-to-event outcome. The timeframe is baseline imaging collection. The accompanying description says the study would evaluate three tibia image sets—X-ray, CT and Digital Tomosynthesis—for acceptable image quality and clinical and diagnostic value.

Such an endpoint can describe whether injury was identified in the images under review. The broader rationale in the record is that tomosynthesis might replace or complement existing imaging, with clinical utility considered in relation to imaging procedures and diagnostic strategy. The record also describes independent review by the principal investigator or designee to assess whether TOMO images could provide clinical equivalence to images from other FDA-cleared imaging systems.

In general, an endpoint needs a clearly specified assessment procedure to support interpretation. For a detection outcome, relevant details can include how the injury status is established, who reviews each image, whether reviewers are masked, and how disagreements are handled. Those details are not reported in the registry record. The record also does not give the observed number of participants with detected tibia injury, so the endpoint’s numerical result and its precision cannot be assessed. No numerical estimate of sensitivity, specificity or agreement is reported in the registry record, and none should be inferred from the endpoint title alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the design label mean?

The study is recorded as non-randomized and crossover, with no masking. In general, randomization assigns participants or procedures by chance, helping balance known and unknown characteristics across comparison groups. A non-randomized design does not have that protection. Crossover designs involve comparisons across interventions within a participant or unit, but the label alone does not establish the sequence, timing, or conduct of those comparisons. The sequence and timing are not reported in the registry record. Because the record says the arms are not a like-for-like control comparison, readers should not treat the listed groups as if they were randomized, interchangeable groups.

Masking concerns whether people involved in the study are kept unaware of which intervention or image is being assessed. The record lists masking as none. In general, masking can reduce the influence of expectations on assessment, particularly when outcomes require judgment. The record describes independent review by the principal investigator or designee, but does not report whether image readers knew the imaging method or what review procedures were used. Independent review and masking are distinct features and should not be assumed to mean the same thing.

What kind of endpoint is listed?

The outcome is a count of participants for whom tibia injury was detected. In general, a binary outcome records whether an event or condition is present for each observation, and a count can summarize how many participants meet that definition. The record identifies the outcome as a participant count, with baseline imaging collection as its timeframe. It does not report the observed count, an analysis estimate, or a statistical test.

For diagnostic imaging, interpretation depends on the assessment framework. In general, sensitivity describes detection among cases with the condition, while specificity describes correct non-detection among cases without it. These quantities require a defined reference for disease status and enough information about positive and negative assessments. The registry record does not report such a reference procedure or provide the classification counts needed for those measures. The endpoint title alone therefore does not permit calculation of diagnostic accuracy.

What would a confidence interval tell a reader?

In general, a confidence interval describes uncertainty around an estimated quantity under specified statistical assumptions. A narrow interval indicates greater precision than a wide interval, while neither guarantees that the estimate is free from bias. Precision depends on the amount and structure of information in the analysis; validity also depends on whether the design and measurements support the interpretation. No confidence interval is reported for the primary outcome in the registry record, and there is no reported estimate around which to interpret one.

What does the absence of analyses imply?

The record lists zero analyses for its single outcome measure. This is a statement about the analyses reported in the registry record. It should not be expanded into claims about whether investigators performed an analysis elsewhere, why a result was not posted, or what an unreported analysis would show. The record does not report a statistical analysis plan, the model used for any outcome, handling of repeated images, or methods for missing data.

Why does the comparison structure matter?

In general, the value of a comparison depends on how interventions are assigned and how outcome assessment is conducted. Non-randomized comparisons may reflect differences in who receives which procedure or in the circumstances of imaging. In crossover studies, within-participant comparisons can address some stable participant characteristics, but interpretation also depends on the ordering and timing of procedures and whether one procedure can affect later assessments. Those design details are not reported in the registry record. The record itself cautions that the arms are not like-for-like controls, so a conventional causal interpretation of between-arm differences would not be justified.

What can be said about planning illustrations?

In general, a sample-size calculation estimates how many observations a future study might need under chosen assumptions about the effect to detect, the significance level, allocation and statistical model. It is a planning exercise, not a summary of observed evidence, and it is not “observed power.” The registry record does not report its own sample-size justification or design assumptions. Any planning illustration based on an observed effect would depend on an effect estimate, but no primary outcome result is reported in the registry record. Such an illustration should not be read as evidence that the pilot was adequately sized or that an effect was demonstrated.

What is not specified?

The record does not report a detailed statistical analysis plan, interim analyses, adjustment for multiple comparisons, or an approach to missing observations. It also does not report diagnostic adjudication rules, the reference standard, or reader agreement. These are not minor substitutions that can be posted by general statistical knowledge; they are study-specific details needed to assess how an endpoint was generated and analyzed. Without them and without outcome results, statistical interpretation is necessarily limited to the information the registry record states.

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("Standard X-Ray", "Standard CT", "Tomosynthesis")
n      <- c(1, 1, 1)
events <- c(1, 1, 1)
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  Standard X-Ray  1  1  100.0  2.5  100.0  20.7  100.0  15.8  98.7
ARM  Standard CT  1  1  100.0  2.5  100.0  20.7  100.0  15.8  98.7
ARM  Tomosynthesis  1  1  100.0  2.5  100.0  20.7  100.0  15.8  98.7

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one outcome measure and zero analyses. It does not report a statistical analysis plan or identify a hierarchy of primary and secondary hypotheses beyond the listed primary outcome. It also does not report whether other outcomes were assessed outside the registry record. Therefore, the handling of multiplicity—when several outcomes, comparisons or tests can increase the chance of a chance-positive finding—is not reported in the registry record. No adjustment method or testing strategy should be assumed.

Missing-data methods are also not reported in the registry record. The enrollment is 1, but the record does not explain whether any planned image assessments or outcome observations were unavailable, incomplete or excluded. It does not describe an analysis population, such as whether all enrolled participants or only those with complete image sets would be included. The listed three-image-set description does not establish that every image set was collected or evaluated.

In general, missing observations can affect interpretation when their availability is related to participant characteristics, the imaging procedure or the outcome. A transparent account typically explains how much information was missing and how it was handled. The registry record gives no such accounting for the primary endpoint. Since the numerical outcome result is also not reported, readers cannot assess the extent to which missing information may have influenced an estimate. These omissions are uncertainties about the analysis record, not evidence that data were missing or that a particular method was used.

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 posted adverse-event counts list one participant at risk in each of the Standard X-Ray, Standard CT and Tomo groups. For each listed group, serious adverse events are recorded as 0, other adverse events as 0, and deaths as 0. These are the event counts shown in the registry record; they do not provide a comparative safety estimate.

In general, zero observed events do not demonstrate that an intervention has no risk. The ability to detect uncommon events depends on the amount of safety information collected and on how events were sought, defined and reported. The registry record does not describe the adverse-event collection period, monitoring procedures, or completeness of reporting. Enrollment was 1, and the crossover label means the group entries should not automatically be interpreted as separate sets of participants. The record does not explain how the risk counts relate to individual exposure across imaging procedures.

The adverse-event entries should therefore be read narrowly: no serious adverse events, other adverse events or deaths are recorded in the listed groups. They do not establish that no events occurred outside the posted record, and they do not support a broad conclusion about comparative safety.

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

The registry record describes a pilot intended to build an image library and assess whether TOMO could replace or complement existing imaging for hip, wrist or tibia injuries. Its listed primary outcome concerns the number of participants for whom tibia injury was detected at baseline imaging collection. The record does not report a numerical result for that outcome. Accordingly, the posted information does not show how many participants had tibia injury detected or whether TOMO and the other imaging procedures produced similar or different assessments.

The study’s enrollment was 1. The design was non-randomized, masking was none, and the record identifies the arms as not like-for-like controls. These features matter because a difference between procedures, if one were reported, would need to be interpreted in light of how the procedures were selected, compared and reviewed. The registry record does not provide the details or outcome results needed to estimate a comparative effect or its precision.

The record does not establish diagnostic accuracy, clinical equivalence, replacement of an existing procedure, or improvement in diagnostic strategy. It also does not establish that TOMO is ineffective. Those conclusions would require evidence not reported in the registry record, including interpretable outcome results and a clear account of assessment and comparison methods. The stated objective and endpoint describe what the study sought to evaluate; they are not results.

The safety entries show zero recorded serious adverse events, other adverse events and deaths in each listed group, with one participant at risk in each. Those counts are a limited description of the posted record, not proof of absence of risk. The appropriate reading is that the registry documents a terminated pilot and its intended imaging assessment, but does not report the numerical primary outcome or analysis needed to answer the diagnostic comparison question.

14. Why This Trial Matters Statistically

This study is statistically notable because it illustrates the difference between a registered research question and a reported result. The record defines an imaging objective and a participant-count endpoint, but lists zero analyses and no numerical primary outcome. Without an estimate, readers cannot judge the direction, size or precision of a result. A stated aim to assess clinical equivalence does not itself demonstrate equivalence.

The design also makes clear why comparison labels need context. A non-randomized crossover study is not automatically comparable to a randomized controlled trial. The registry explicitly cautions that the arms are not like-for-like controls and says standard care would be chosen per subject. In general, assignment and assessment procedures influence whether observed differences can be attributed to an intervention. The record does not give enough detail about sequence, timing or image review to resolve those issues.

Enrollment of 1 places the record in a pilot context and limits what can be learned about variability across participants. The registry does not report a sample-size justification, analysis plan, or outcome estimate. This prevents readers from assessing whether a planned precision or power target was met. In general, sample-size planning is not a substitute for observed data, and a planning illustration based on an effect does not constitute evidence that the effect occurred.

The record is also a useful reminder that diagnostic endpoints need a defined assessment framework. A count of detected injuries is not, by itself, enough to establish diagnostic accuracy or clinical equivalence. Interpretation would require clarity about the reference for injury status, image-reading procedures and outcome classification. These details are not reported in the registry record. The statistical significance of this case is therefore methodological: it shows how much a brief registry entry can define about intent while leaving unanswered questions about results, measurement and analysis.

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.

Several limitations specific to this study constrain interpretation. The registry reports enrollment of 1, yet the planned primary outcome description refers to three tibia image sets: one X-ray, one CT and one Digital Tomosynthesis. The record does not report the number of completed image sets or whether all were evaluated. It is therefore not possible to establish from the record how complete the planned image collection was.

The stated clinical population includes hip, wrist or tibia injuries, whereas the listed primary outcome is specific to tibia injury detection. The record does not report separate outcome results for hip or wrist imaging. Its objective of building an image library is broader than the one registered outcome measure, but whether that library was completed is not reported in the registry record.

The comparison structure is also not fully described. The listed interventions include Standard X-Ray + CT and Standard X-Ray + MRI, while the outcome population description refers to X-ray, CT and Digital Tomosynthesis. The arm descriptions say standard care would be selected per subject, and the record warns that the arms are not like-for-like controls. The relationship among these descriptions, the sequence of imaging, and the crossover process is not reported in enough detail to infer a uniform comparison.

Masking is listed as none. The record describes an independent review by the principal investigator or designee, but does not report whether reviewers knew the imaging modality, how image quality was rated, or how disagreements were resolved. It also does not report the diagnostic reference standard, analysis plan, handling of missing information, or the reason for termination. Most importantly, no numerical primary outcome or analysis result is reported. These gaps prevent assessment of the observed diagnostic findings and their precision.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Pilot Study Comparing Diagnostic Imaging Versus Tomosynthesis in Detection of Hip, Wrist or Tibia Injury — NCT01927575.
• Registry record last updated 2020-06-04; status last verified 2020-05.
• Results first posted 2017-06-05.
• 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 record describes a terminated pilot study of imaging for hip, wrist or tibia injury, sponsored by Fujifilm Medical Systems USA, Inc. It lists a start date of 2013-09, a primary completion date of 2014-04, enrollment of 1, non-randomized allocation, no masking and a crossover model. The phase is recorded as not applicable.

Interventions include Standard X-Ray + CT, Standard X-Ray + MRI and TOMO. The primary outcome is the number of participants for whom tibia injury was detected at baseline imaging collection. Its description refers to three tibia image sets and an assessment of image quality and clinical and diagnostic value. The record lists one outcome measure and zero analyses.

A numerical primary outcome result and the reason for termination are not reported in the registry record. Adverse-event entries list one participant at risk and zero serious adverse events, other adverse events and deaths in each of the Standard X-Ray, Standard CT and Tomo groups. These entries do not supply a comparative safety estimate.