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 Patient-Assisted Compression in 3D - Impact on Image Quality and Workflow (NCT03456427), a na na study. The primary outcome is Percentage of Acceptable Overall Image Quality.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03456427 |
| Phase | NA |
| Condition | Breast Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 36 |
| Arms in the primary outcome | n/a |
| Lead sponsor | GE Healthcare |
| Results posted | Yes |
2. Clinical Question
Population
People enrolled in a study listed under Breast Cancer. The registry record gives an enrollment of 36, but does not report further participant characteristics.
Intervention
Patient-Assisted Compression (PAC), in which the patient participates in controlling the amount of compression force during mammography.
Comparator
Technologist-Controlled (TC) Compression. The study description says that the other breast was imaged using PAC, followed by TC compression.
Primary question
How does the percentage of acceptable overall image quality compare between unilateral two-view (CC and MLO) breast images acquired using PAC and TC modes?
The registry frames the question around image quality in mammography using the Senographe Pristina 3D platform. Its brief summary also identifies clinical workflow as an area of interest. The listed secondary outcomes are the number of repeat image acquisitions and the percentage of acceptable mammographic attributes.
This is a comparison of compression modes within a study where participants underwent imaging of both breasts in different ways: one breast received standard-of-care imaging, and the other was imaged using PAC followed by TC compression. The record does not describe this as a randomized comparison. The order of PAC and TC is stated, but further details about how the imaging procedures were evaluated are not reported in the registry record.
The primary question is therefore specific to the acceptability of overall image quality under the two compression modes. It is not a question about cancer detection, diagnosis, or patient outcomes. The registry record does not report numerical results for the primary question, so the direction and precision of any observed comparison cannot be established from that record.
3. Trial Design
The registry describes a completed, single-group study sponsored by GE Healthcare, with an enrollment of 36. The condition listed is Breast Cancer. The phase is recorded as NA, the allocation as NA, and masking as NONE. Its start date is 2018-01-04, and its primary completion date is 2018-01-09.
The study description says all participants would undergo standard-of-care imaging on one breast. The other breast would be imaged using Patient-Assisted Compression (PAC), followed by Technologist-Controlled (TC) Compression. The interventions are listed as devices. This arrangement means that the compression-mode comparison is described within the same participant, rather than as a comparison between separately assigned treatment groups. The record does not provide enough detail to characterize the precise analysis of this within-participant structure.
The primary objective concerns acceptable overall image quality in unilateral two-view (CC and MLO) breast images obtained using PAC and TC modes. Its timeframe is listed as 1 Day. The secondary outcomes concern repeat image acquisitions and acceptable mammographic attributes. The record lists 3 outcome measures and 0 analyses.
Although the study status is COMPLETED, completion status does not itself supply outcome findings. Numerical results, analysis methods used for the primary comparison, and participant-level analysis details are not reported in the registry record. Allocation is listed as NA, so this should not be described as a randomized trial. The record also does not report a masking procedure; masking is listed as NONE.
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 Study Participants |
|---|---|
| STARTED | 36 |
| COMPLETED | 33 |
| NOT COMPLETED | 3 |
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 Study Participants |
|---|---|---|
| Participants analysed | 33 | |
| Age, Continuous | years | 66.45 (SD 10.99) |
| Sex: Female, Male: Female | Participants | 33 |
| Sex: Female, Male: Male | Participants | 0 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 4 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 29 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Menopausal Status: Post-Menopausal | Participants | 29 |
| Menopausal Status: Perimenopause | Participants | 2 |
| Menopausal Status: Pre-Menopausal | Participants | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Acceptable Overall Image Quality, measured over 1 Day.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is titled Percentage of Acceptable Overall Image Quality. It concerns the percentage of participants whose unilateral two-view breast images—CC and MLO views—are judged to have acceptable overall image quality when acquired using PAC and TC compression modes. The registry lists the unit as participants, the parameter as a count of participants, and the timeframe as 1 Day.
Image acceptability is a way to assess whether acquired images meet a defined quality standard. In general, such an endpoint can summarize whether images are considered usable according to the study’s assessment criteria. The registry record, however, does not report those criteria, how acceptability was judged, who performed the assessment, or whether assessors were masked. It also does not give the observed counts or percentages for either compression mode.
The endpoint is relevant to the stated objective because it focuses on overall image quality under the two modes, rather than on a clinical outcome such as diagnosis. The record lists repeat image acquisitions and the percentage of acceptable mammographic attributes as secondary outcomes, which address additional aspects of image acquisition and quality. Their numerical results are not reported in the registry record.
Without the endpoint counts and a description of the analysis, readers cannot determine how large or precise the comparison was. The endpoint definition identifies what the study intended to assess; it does not, by itself, establish which mode had more acceptable images or whether any observed difference would be meaningful.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a primary comparison but does not report its numerical results. In particular, it does not give the number or percentage of participants with acceptable overall image quality under PAC or TC compression, an estimated difference between modes, or a confidence interval. It lists 0 analyses. Consequently, the record does not support a conclusion about the direction, size, or statistical precision of the primary comparison.
The study design describes imaging under both compression modes within a participant: one breast was imaged using PAC and then TC, while the other underwent standard-of-care imaging. This is not presented as a randomized, parallel-group comparison. A statistical interpretation should therefore keep the described imaging arrangement in view rather than treating the study as though participants were assigned to separate PAC and TC groups. The registry record does not provide enough analysis detail to determine how the relationship between observations from the same participant was handled.
In general, a percentage describes the share of observations meeting a defined criterion, while an interval estimate conveys uncertainty around an estimate. For a within-participant comparison, the association between observations from the same participant can matter to the uncertainty calculation. These general points do not identify the method used in this study: the analysis method, interval estimates, and hypothesis-test results are not reported in the registry record.
The stated planning illustration uses a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. Such assumptions describe a planning exercise; they do not replace the trial’s own design or establish the precision of its actual findings. The trial’s own sample-size justification is not reported in the registry record. A planning illustration based on an observed effect is not observed power, and the registry record does not provide an observed primary effect from which to interpret such an illustration.
The registry lists the study as completed, but completion is not evidence that the primary outcome favored either mode. No inferential result is reported, and no finding about image quality or workflow should be attributed to the study on the basis of the design description alone. The appropriate reading is that the record states what the investigators intended to compare, while leaving the result and its uncertainty unreported.
9. Statistical Methods Explained
What does the endpoint count?
The primary endpoint is a participant-level measure of acceptable overall image quality. The registry describes the target as a percentage and identifies the unit as participants and the parameter as a count of participants. In general, a binary endpoint classifies an observation into categories such as acceptable or not acceptable. A count of participants meeting the acceptable criterion can then be used to describe the percentage meeting that criterion, if the relevant denominator and outcome data are available.
The record does not state the observed counts or percentages for PAC or TC images. It also does not describe the operational criteria for acceptability or the procedure used to apply them. Thus, the endpoint’s name and objective can be explained, but its observed distribution cannot be reconstructed from the registry record.
Why does the study arrangement matter?
The design description places both compression modes within a participant’s imaging experience: the other breast was imaged using PAC, followed by TC compression. In general, observations collected from the same participant may be associated. A method for paired or otherwise correlated observations can account for that association, whereas treating every observation as independent may misstate uncertainty. This is a general statistical consideration, not a description of the method used in this study. The statistical method for the primary comparison is not reported in the registry record.
The record also says one breast received standard-of-care imaging. That description should not be confused with a randomized allocation to PAC or TC arms: allocation is recorded as NA, and the study model is SINGLE GROUP. The registry does not explain whether or how standard-of-care images entered the primary endpoint analysis.
What would an estimate and interval communicate?
In general, an estimate summarizes the observed comparison, while a confidence interval describes the range of values compatible with the data under a stated statistical procedure. A narrower interval indicates greater precision under that procedure; a wider interval indicates more uncertainty. The interval’s interpretation depends on the analysis method and assumptions. Neither an estimate nor an interval is reported for the primary comparison in the registry record, so no precision judgment can be made about the observed image-quality contrast.
A hypothesis test, when used, evaluates data against a specified null hypothesis under assumptions. Its result does not by itself express the size or practical relevance of an effect. The registry record lists 0 analyses and does not report a test statistic or p-value. It therefore does not establish whether a test was conducted or what its result was.
Why can over-dispersion matter?
In general, over-dispersion means that observed variability is greater than a statistical model assumes. If a model underestimates variability, standard errors may be too small and intervals may be too narrow. This issue can arise in some count-data settings when observations vary more than a basic model allows. The primary endpoint is described as a participant count for a binary acceptability outcome, but the registry record does not report a model or any over-dispersion assessment. It would be inappropriate to claim that over-dispersion was present or that a particular adjustment was used.
How should planning assumptions be read?
The stated sample-size assumptions describe a planning illustration based on the observed effect: a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. In general, a sample-size calculation estimates the number of participants needed under its assumptions to target a chosen power and significance level. It is conditional on the assumed effect and analysis framework.
These planning calculations are not observed power and do not show how precise the completed study’s result was. The registry record does not report its own sample-size justification, and it does not report the numerical primary effect needed to assess an effect-based planning illustration. The listed equal-allocation assumption also does not change the registry’s single-group design description or establish that the trial enrolled separate randomized arms.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary outcome, Percentage of Acceptable Overall Image Quality, and two named secondary outcomes: Number of Repeat Image Acquisitions and Percentage of Acceptable Mammographic Attributes. It also lists 3 outcome measures and 0 analyses. The analysis methods and numerical findings for these outcomes are not reported in the registry record.
Multiplicity arises in general when several outcomes, comparisons, or analyses are examined. If many statistical tests are performed, the chance of at least one apparently unusual result can increase unless the analysis plan addresses that issue. The registry record does not report whether multiplicity was considered, whether any adjustment was planned, or how the primary and secondary outcomes were prioritized in analysis. No adjustment method should be inferred from the list of endpoints alone.
Information about missing outcome data is not reported in the registry record. The record does not state whether all enrolled participants contributed primary-endpoint observations, how missing image assessments were handled, or whether any sensitivity analyses were planned or performed. Without those details, the completeness of the endpoint data and the possible effect of missingness cannot be assessed.
The analysis populations are not reported in the registry record. It does not specify an intention-to-treat, per-protocol, or other analysis set. The participant-level endpoint and within-participant imaging description do not establish, by themselves, which observations were included in an analysis.
These gaps matter because the interpretation of a comparison depends not only on the endpoint definition, but also on which observations were analyzed, how missing data were treated, and how multiple outcomes were handled. With 0 analyses listed and no corresponding results, the registry does not permit an assessment of these choices.
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 Study Participants | 0 | 36 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| All Study Participants | 0 of 36 |
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 Study Participants | 0 of 36 |
The registry safety figures list All Study Participants as the group. For serious adverse events, 36 participants are listed as at risk and 0 as affected. For other adverse events, 36 are listed as at risk and 0 as affected. Deaths are listed as 0. These are the recorded counts; they should not be converted into additional percentages or interpreted as evidence beyond the registry entry.
The record does not list serious adverse-event terms. It also does not provide detailed definitions, event descriptions, assessment procedures, or a fuller account of how safety events were collected. The recorded zero counts therefore mean that no affected participants are entered in those registry fields; they do not answer questions the record does not report, such as the completeness of event ascertainment.
These safety entries are separate from the primary image-quality endpoint. They do not provide evidence about whether PAC or TC produced better image quality, nor do they establish a causal comparison between the compression modes. The study is described as single-group, and the safety figures are presented for All Study Participants rather than as a randomized between-group safety contrast.
When reading zero counts, distinguish the registry’s recorded values from a broader claim that an event is impossible or that no unrecorded event occurred. The record reports 0 affected for the listed categories and 0 deaths; details needed for a more extensive safety interpretation are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record establishes that the study was designed to assess image quality and workflow in relation to PAC use with the Senographe Pristina 3D platform. It specifies a primary image-quality question comparing PAC and TC modes, and names repeat image acquisitions and acceptable mammographic attributes as secondary outcomes. It also describes an imaging sequence in which the other breast was imaged with PAC followed by TC.
Those design details do not establish the result. The primary outcome counts, percentages, estimated comparison, confidence interval, and inferential analysis are not reported in the registry record. The record lists 0 analyses. It therefore does not show whether image acceptability was higher under either mode, how large any difference was, or how precisely a difference was estimated. The completed status does not fill in these missing results.
The study also does not answer every question that might arise about mammography. Its primary endpoint concerns acceptability of overall image quality for unilateral two-view (CC and MLO) breast images. The record does not report cancer-detection outcomes, diagnostic accuracy, or patient outcomes as primary findings. Although the brief summary mentions discomfort as background for PAC, the listed outcomes do not include a reported discomfort result.
The study design should not be described as randomized: allocation is listed as NA, and the model is SINGLE GROUP. The record does not provide enough detail to judge how within-participant association was handled, how acceptability was assessed, or what analysis population was used. Accordingly, no causal or comparative claim should be drawn from the design description alone.
The sound conclusion is limited: the registry specifies a comparison and its intended outcomes, but does not report the findings needed to evaluate the comparison. No claim that one compression mode is superior, equivalent, or inferior is supported by the registry record.
13. Why This Trial Matters Statistically
This study raises a useful statistical issue: how to compare image-quality outcomes when the study description places both compression modes within a participant’s imaging. In general, observations from the same participant can be related. Accounting for that relationship is important when estimating uncertainty, because a method that ignores it may not represent the data structure well. The registry record does not report the method used, so the design makes the issue relevant without revealing how it was handled.
The endpoints also distinguish overall image acceptability from other acquisition-related measures. Repeat image acquisitions and acceptable mammographic attributes address aspects that are not identical to the primary endpoint. In general, having several outcomes can broaden the evaluation, while also raising questions about outcome priority and multiplicity. The registry record does not report an analysis plan or multiplicity procedure.
The case also illustrates why study completion and study results are different kinds of information. The registry labels the study COMPLETED and records an enrollment of 36, yet it lists 0 analyses and does not report primary outcome values. A design description can establish what was intended to be examined, but an interpretation of effects requires the observed results and enough information to understand their analysis.
Finally, planning assumptions should be kept separate from evidence about a completed study. An effect-based sample-size illustration can clarify how planning depends on assumptions, but it is not a substitute for an observed estimate and its uncertainty. The trial’s own sample-size justification is not reported in the registry record. These distinctions help prevent design details or planning exercises from being mistaken for evidence about image quality.
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 main limitation for interpretation is that the registry record does not report numerical primary or secondary outcome results. The primary comparison therefore cannot be described in terms of its observed direction, magnitude, or precision. Although the study status is COMPLETED, the record lists 0 analyses.
The description identifies a single-group model, allocation recorded as NA, and no masking. It does not describe a randomized comparison. The other breast was imaged using PAC followed by TC, but the registry does not report enough detail to determine how the within-participant relationship was incorporated into the analysis or how standard-of-care imaging related to the primary analysis.
Further endpoint details are not reported in the registry record. These include the criteria for acceptable overall image quality, how image assessments were conducted, who judged acceptability, and whether image assessors were masked. The record also does not report the analysis population, missing-data handling, or a multiplicity approach.
The registry lists an enrollment of 36, but does not provide participant characteristics or explain the trial’s sample-size justification. The stated planning illustration assumptions do not supply an observed treatment-mode effect or a result-specific precision estimate. Safety entries report 0 affected for serious and other adverse events and 0 deaths, but details on event definitions and ascertainment are not reported.
These limitations do not negate the stated objective; they constrain what can be concluded from the registry record. In particular, design and endpoint descriptions cannot substitute for the missing estimates and analysis details.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Patient-Assisted Compression in 3D - Impact on Image Quality and Workflow — NCT03456427.
- Registry record last updated 2019-04-05; status last verified 2019-01.
- Results first posted 2019-04-05.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT03456427 is a completed, single-group study titled Patient-Assisted Compression in 3D - Impact on Image Quality and Workflow. GE Healthcare is listed as sponsor. The registry records an enrollment of 36, a start date of 2018-01-04, and a primary completion date of 2018-01-09. Phase and allocation are listed as NA, and masking is listed as NONE.
The study description says participants received standard-of-care imaging on one breast and PAC followed by TC compression on the other. The primary objective compares acceptable overall image quality for unilateral two-view (CC and MLO) images. Secondary outcomes concern repeat image acquisitions and acceptable mammographic attributes.
The record lists 3 outcome measures and 0 analyses. Numerical primary and secondary outcome results are not reported in the registry record. Safety fields list 0 affected for serious events, 0 affected for other events, and 0 deaths.