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 Wrist Fracture Evaluation With a Desktop Orthopedic Tomosynthesis System (NCT03993691), a na na study. The primary outcome is Sensitivity.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03993691 |
| Phase | NA |
| Condition | Fracture |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of North Carolina, Chapel Hill |
| Results posted | Yes |
2. Clinical Question
Population
Participants had standard-of-care, conventional 2D radiographic imaging for presumed or known scaphoid, wrist, or distal radius fractures. The registry record lists 30 enrolled participants. It does not report their age, fracture characteristics, or other baseline details.
Intervention
Participants received a Tomo-E scan within two weeks of the conventional radiographic imaging. The primary outcome concerns readers’ ability to detect wrist fractures on the Tomo-E scans.
Comparator
Conventional radiography was part of standard care, but the study is registered as single-group, with allocation listed as NA and no masking. It is not a randomized, like-for-like comparison between separate treatment groups. For the primary diagnostic assessment, fracture status was clinically determined by the attending orthopedic surgeon.
Primary question
How sensitive is Tomo-E for detecting wrist fractures when radiologists read the scans and fracture status is based on the attending orthopedic surgeon’s clinical determination? The registry also lists specificity as a secondary outcome, but numerical results for either measure are not reported in the registry record.
This is a diagnostic-imaging question, not a question about treatment assignment or patient outcomes. Sensitivity describes detection among cases classified as having a fracture by the reference determination. Specificity concerns classification among cases without a fracture by that determination. These measures address different kinds of diagnostic error and require the underlying classifications to interpret.
The registered description says that Tomo-E scans would be reviewed in a standardized reader study at the conclusion of all study imaging. It does not report how many scans were classified as fracture-positive or fracture-negative, how readers’ classifications were combined, or the resulting accuracy estimates. Thus the clinical question is clear, but the posted registry information does not give a numerical answer.
3. Trial Design
This completed study evaluated a desktop orthopedic tomosynthesis system for wrist-fracture imaging. It is registered as a single-group study, with allocation listed as NA and masking listed as none. The record lists 30 participants. The sponsor is the University of North Carolina, Chapel Hill. The recorded study start date is 2019-11-05, and the primary completion date is 2021-11-03.
Participants had conventional 2D radiographic imaging as part of standard care for presumed or known scaphoid, wrist, or distal radius fractures. They received Tomo-E scans within two weeks. The registry describes the Tomo-E scans as being assessed in a standardized reader study after all study imaging was complete. This design does not assign participants to separate randomized imaging groups. The conventional radiograph is part of the clinical context; the registry’s stated reference for diagnostic accuracy is the attending orthopedic surgeon’s clinical determination of whether a fracture was present.
The primary outcome is sensitivity, with a stated timeframe of 8 months. Specificity is listed as a secondary outcome. Although the record describes two outcome measures, it does not provide numerical outcome results or analysis records. The absence of a posted analysis means that details such as the number of readers, the handling of multiple readings, and the statistical methods used for the final accuracy estimates are not reported in the registry record.
The design is relevant when interpreting what the study can establish. It can be described as an evaluation of Tomo-E scans in participants who also underwent conventional radiography, not as a randomized comparison of imaging strategies. The record does not report whether readers were blinded to other imaging or clinical information, so the potential influence of that information cannot be assessed from the registry entry.
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 | All Participants |
|---|---|
| STARTED | 30 |
| COMPLETED | 30 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | All Participants |
|---|---|---|
| Participants analysed | 30 | |
| Age, Continuous | years | 63 (SD 15) |
| Sex: Female, Male: Female | Participants | 26 |
| Sex: Female, Male: Male | Participants | 4 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 29 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 2 |
| Race (NIH/OMB): White | Participants | 27 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | Participants | 30 |
6. Primary Endpoint
The registry lists the primary outcome as Sensitivity, measured over 8 months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percent of scans with a fracture |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is sensitivity, described as the ability of radiologist readers to detect wrist fractures on Tomo-E scans. The registry gives the endpoint unit as percent of scans with a fracture and identifies the attending orthopedic surgeon’s clinical determination as the basis for deciding whether a fracture was present. It states that the scans would be reviewed in a standardized reader study after all study imaging was complete. The registered timeframe is 8 months.
In general, sensitivity describes how often a diagnostic method identifies a condition among cases classified as having that condition by the chosen reference determination. It is useful because a diagnostic method may fail to identify some cases that are considered to have the condition. Interpreting a sensitivity estimate requires knowing the number of reference-positive cases and how many were identified by the readers. Neither those counts nor a numerical sensitivity estimate is reported in the registry record.
The reference determination matters. Here, the record names the attending orthopedic surgeon’s clinical determination, but does not describe the criteria used, the information available to the surgeon, or whether that determination was made independently of the imaging under evaluation. Those details affect how readers should understand the endpoint as a measure of agreement with the clinical reference, rather than an error-free measure of underlying fracture status.
Specificity is listed as a secondary outcome. In general, specificity concerns recognition of cases classified as not having the condition. Its numerical result and the counts needed to interpret it are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the intended diagnostic question and the study population, but it does not post numerical sensitivity or specificity results. There is therefore no reported estimate of how often readers detected fractures on Tomo-E scans, no estimate of how often fracture-negative cases were correctly classified, and no reported uncertainty interval for either measure. The listed enrollment of 30 participants describes the study size, not the number of cases contributing to each diagnostic-accuracy denominator.
For sensitivity, interpretation depends on the cases that the attending orthopedic surgeon classified as having a fracture and on the readers’ assessments of those scans. Without the number of reference-positive cases, the number detected, or the resulting estimate, the endpoint cannot be quantified from the registry record. The same issue applies to specificity: its interpretation requires information about reference-negative cases and their reader classifications, none of which is reported.
In general, a confidence interval conveys the range of values compatible with an estimate under the statistical method used. It helps readers judge precision, which is influenced by the number of relevant cases and by the observed classifications. No confidence interval or other measure of precision is reported in the registry record. A numerical result without its denominator and uncertainty would also be difficult to assess, particularly in a diagnostic study where sensitivity and specificity depend on different subsets of cases.
The design also constrains the comparison that can be made. Participants received conventional radiography as standard care and then received Tomo-E scans within two weeks, but the registered study is single-group rather than a randomized comparison. The registry’s primary reference is the surgeon’s clinical determination, not a stated head-to-head statistical test of Tomo-E against radiography. It would therefore be inappropriate to infer comparative accuracy, superiority, or equivalence from the design description alone.
The record lists no analysis records, and the diagnostic outcome values are not reported in the registry record. It does not state whether estimates were adjusted, how readings from different radiologists were handled, or whether results were assessed at the scan, participant, or reader level. These are important analytical choices because repeated readings or multiple scans from a participant may not be statistically independent. The posted information does not establish which approach was used.
Accordingly, the registry supports a description of the question, timing, and broad study structure, but not a conclusion about the observed diagnostic performance. That limitation is about the available results, not evidence that the device had either high or low accuracy. No treatment-effect conclusion follows from a study designed around diagnostic imaging outcomes.
9. Statistical Methods Explained
The primary outcome is a diagnostic-accuracy measure rather than a treatment-effect measure. In general, diagnostic accuracy compares a test classification with a reference classification. Sensitivity concerns the test’s identification of cases classified as having the condition. Specificity concerns correct classification among cases classified as not having it. These measures answer related but distinct questions; a single overall label of accuracy cannot replace both.
What does sensitivity represent?
For this study, the test classification comes from radiologists’ readings of Tomo-E scans. The reference classification is the attending orthopedic surgeon’s clinical determination of fracture status. The registry describes the endpoint as sensitivity and identifies its unit as percent of scans with a fracture. In general, the estimate depends on the reference-positive cases and on which of those cases readers identify. The registry record does not report those counts or the resulting estimate, so sensitivity cannot be reconstructed from the posted information.
The reference standard is part of the meaning of a diagnostic estimate. A sensitivity estimate describes agreement with the selected reference classification; it does not by itself establish an independent, error-free account of disease status. The record does not describe the surgeon’s criteria or whether the surgeon’s determination was independent of the imaging being evaluated. Those details are not reported in the registry record and should not be assumed.
How does specificity differ?
Specificity is listed as a secondary outcome. In general, it concerns whether cases classified as not having a fracture by the reference are also classified as negative by the test readers. Sensitivity and specificity rely on different reference-status groups. A reader cannot interpret one as a substitute for the other, and neither measure alone describes every aspect of diagnostic performance. The registry does not post the specificity estimate, its denominator, or its uncertainty.
Why do denominators and uncertainty matter?
Diagnostic estimates are proportions based on observed classifications. In general, the number of relevant cases affects how precisely an estimate can be interpreted: estimates based on limited information can vary substantially across samples. A confidence interval is a way to express uncertainty around an estimate under a stated statistical model. It is not a guarantee that the reference classification is correct, nor does it resolve design limitations. The registry record reports neither diagnostic estimates nor confidence intervals, so precision cannot be assessed.
The enrollment of 30 is not necessarily the denominator for either outcome. Sensitivity uses reference-positive cases, while specificity uses reference-negative cases. The registry does not report how the enrolled participants were distributed across these groups or whether all enrolled participants contributed evaluable scans and readings. It also does not report a participant flow or a count of excluded or unevaluable observations.
What can be said about the analysis?
The record says that all Tomo-E scans would be reviewed in a standardized reader study at the conclusion of all study imaging. It does not report the statistical method for combining or summarizing reader assessments. For example, it does not say whether readers’ results were presented separately, combined, or analyzed with a method that accounts for multiple readings of the same scan. These choices can affect both the estimate and its uncertainty, especially when observations share a participant or scan.
No analysis records are listed. The registry does not report whether confidence intervals, hypothesis tests, adjustments, or sensitivity analyses were used. It also does not provide a statistical analysis plan in the registry record recorded for this study. Such methods should not be inferred from the outcome definitions alone.
How should planning illustrations be understood?
General planning calculations estimate the number of participants needed under specified assumptions. They are not observed trial results and are not evidence that a study had a particular probability of detecting an effect. The planning assumptions associated with this record describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. Those are assumptions for an illustration; the registered study itself is single-group, and the posted diagnostic outcome results needed to identify an observed effect are not reported in the registry record. The planning assumptions therefore should not be read as the study’s actual design or as observed power.
Overall, the statistical concepts clarify what the registered outcomes are intended to measure, but they cannot supply missing numerical results or unreported analytical choices. The registry record establishes the planned diagnostic question and names the reference determination; it does not give enough information to reproduce or evaluate the final sensitivity and specificity analyses.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists sensitivity as the primary outcome and specificity as a secondary outcome. It lists two outcome measures and zero analysis records. The record does not report whether the investigators tested multiple hypotheses, adjusted for multiple comparisons, or designated any additional outcomes for confirmatory interpretation. A multiplicity strategy is therefore not reported in the registry record.
Multiplicity matters in general when several outcomes, comparisons, or analysis choices are examined. The more results considered, the more important it is to know which analyses were planned and how the results were interpreted. Here, the registry identifies the primary and secondary outcome roles, but it does not report a statistical analysis plan or the final analysis details. No claim about adjustment or unadjusted testing can be made from the outcome listing alone.
Missing-data handling is also not reported in the registry record. The entry does not state whether any participants lacked an evaluable Tomo-E scan, a reader assessment, or a clinical reference determination. It does not report exclusions, incomplete assessments, or the approach used if information was missing. The enrollment count of 30 does not establish that all participants contributed to every outcome.
The analysis populations are not reported in the registry record. There is no stated set of participants or scans included in the sensitivity or specificity calculations, and no account of whether all readers or readings were retained. These omissions matter because diagnostic accuracy depends on reference classifications and corresponding test readings. Without the analysis denominators and missingness information, neither the completeness nor the representativeness of the diagnostic estimates can be assessed.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| All Participants | 0 | 30 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| All Participants | 0 of 30 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| All Participants | 0 of 30 |
The registry’s adverse-event figures list 30 participants at risk for serious adverse events and 0 affected. The same figures list 30 at risk for other adverse events and 0 affected. The deaths count is 0, and no top serious-event terms are listed. These are the recorded counts in the registry entry; they do not provide a description of event definitions, collection procedures, or the period over which events were monitored.
A zero count means that no affected participants are recorded in these registry fields. It does not establish that the imaging procedure is risk-free, nor does it explain whether events were actively sought or how causality was assessed. The record does not report event-specific details beyond the listed counts, so readers cannot assess the nature or timing of any events from this entry.
Safety counts should be read separately from diagnostic performance. They do not indicate whether Tomo-E detected fractures accurately, and the absence of reported events does not supply missing sensitivity or specificity results. The registry information is limited to the listed at-risk and affected counts.
12. What the Result Does, and Does Not, Mean
The registry describes a completed diagnostic-imaging study in which participants received Tomo-E scans after conventional radiography. It identifies sensitivity as the primary outcome, defines fracture status by the attending orthopedic surgeon’s clinical determination, and lists specificity as a secondary outcome. These details show what diagnostic question the study was intended to address.
The registry does not report numerical sensitivity or specificity results. It also does not provide the counts of reference-positive and reference-negative cases, the reader classifications, or uncertainty intervals. Consequently, the posted record does not establish a numerical level of diagnostic performance or its precision. This absence should not be interpreted as evidence for either favorable or unfavorable performance.
The study’s single-group design also sets a boundary on interpretation. Although conventional radiography was part of standard care, the record does not describe a randomized head-to-head comparison of imaging methods. Nor does the primary endpoint, as registered, measure clinical outcomes such as recovery or changes in care. Diagnostic accuracy against the stated clinical reference is not the same as proof of patient benefit.
In general, an imaging result can be interpreted only in relation to its reference standard, the cases included, the way scans were read, and the statistical uncertainty around the estimate. Several of these details are not reported in the registry record. The entry therefore supports a cautious account of the study’s purpose and structure, but not conclusions about how Tomo-E compares with radiography or how a scan result affected clinical decisions.
The listed zero counts for serious adverse events, other adverse events, and deaths are safety-record entries, not evidence about diagnostic accuracy. They should be understood within the limits of the event information recorded, rather than as a broad statement about risk.
13. Why This Trial Matters Statistically
This study raises a statistical question that is central to diagnostic research: how well do readers identify cases against a stated reference determination? That question requires more than a device description. It requires a clear definition of the reference status, the test readings, the relevant denominators, and measures of uncertainty. The registry identifies the intended sensitivity outcome and names the attending orthopedic surgeon’s clinical determination as the reference, but does not post the numerical results needed to judge performance.
The distinction between sensitivity and specificity is also important. They concern different reference-status groups and can convey different aspects of diagnostic classification. Reporting both with their denominators and uncertainty would allow readers to understand how the test performed across fracture-positive and fracture-negative cases. The registry lists specificity as secondary but does not report either outcome estimate.
Study structure matters to statistical interpretation. This is a single-group evaluation, not a randomized trial with separate imaging arms. Conventional radiography was received as standard care, while Tomo-E scans followed within two weeks. The registered endpoint uses a clinical reference determination rather than a stated randomized comparison. Recognizing that distinction helps prevent an accuracy question from being recast as a comparative-effectiveness result.
The record also illustrates why enrollment alone is insufficient to interpret diagnostic estimates. Sensitivity and specificity depend on the numbers of reference-positive and reference-negative cases and on the corresponding readings. The total enrollment does not reveal either denominator. Without outcome counts and precision measures, readers cannot tell how stable an estimate would be or how broadly it might apply.
Statistically, the most informative conclusion is therefore about what remains necessary for interpretation: diagnostic results, analysis denominators, reader-handling methods, and uncertainty. Their absence in the registry record limits conclusions without resolving the underlying clinical question.
14. 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 registry record provides limited detail for assessing the diagnostic results. It lists 30 enrolled participants, but does not report the number with a fracture according to the attending orthopedic surgeon, the number without a fracture, or how many contributed evaluable scans and readings. Those counts are essential context for sensitivity and specificity.
The study is registered as single-group, with allocation listed as NA and masking listed as none. The record does not describe whether radiologist readers had access to conventional radiographs, clinical information, or the surgeon’s determination. It also does not report the number of readers or how reader-level assessments were combined. These unreported details limit assessment of possible information effects and the statistical handling of repeated readings.
The reference standard is described as the attending orthopedic surgeon’s clinical determination, but the criteria and process for that determination are not reported in the registry record. The information does not establish whether the determination was made independently of the scans under evaluation. This limits how specifically agreement with the reference can be interpreted.
The participant and fracture characteristics are not reported in the registry record beyond the stated context of presumed or known scaphoid, wrist, or distal radius fractures. The record does not provide subgroup results or enough detail to assess whether the observed cases represent other clinical settings. Numerical outcome results, confidence intervals, missing-data handling, and analysis populations are also not reported.
Finally, the study’s timing and design do not establish a randomized comparison of imaging methods or an effect on patient outcomes. The registry describes Tomo-E scans within two weeks after conventional imaging, but does not report comparative accuracy estimates. These limitations are specific to the information recorded and should not be filled by assumptions.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Wrist Fracture Evaluation With a Desktop Orthopedic Tomosynthesis System — NCT03993691.
- Registry record last updated 2023-02-03; status last verified 2021-12.
- Results first posted 2022-11-07.
- 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.
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18. Record Summary
NCT03993691 is a completed, single-group study titled Wrist Fracture Evaluation With a Desktop Orthopedic Tomosynthesis System. It lists 30 participants and the University of North Carolina, Chapel Hill as sponsor. The recorded start date is 2019-11-05, and the primary completion date is 2021-11-03.
Participants underwent conventional 2D radiographic imaging for presumed or known scaphoid, wrist, or distal radius fractures and received Tomo-E scans within two weeks. The primary outcome was sensitivity, defined through radiologist detection of fractures using the attending orthopedic surgeon’s clinical determination as the reference. Specificity was listed as a secondary outcome.
The registry lists 0 affected participants for serious adverse events, 0 for other adverse events, and 0 deaths among 30 at risk in each adverse-event category. Numerical diagnostic outcome results, analysis records, and further analysis details are not reported in the registry record.