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 Evaluation of Half-Dose Molecular Breast Imaging With Wide Beam Reconstruction Processing (NCT01653964), a na na study. The primary outcome is Compare the Diagnostic Accuracy of 8 mCi Molecular Breast Imaging (MBI) With 4 mCi MBI..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01653964 |
| Phase | NA |
| Condition | Breast Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 83 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Mayo Clinic |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned patients undergoing molecular breast imaging in the setting of breast cancer evaluation. The primary outcome description says that 82 patients were recruited before breast biopsy and that 34 had a histologically proven breast cancer diagnosis. The registry enrollment is 83, so the enrollment figure and the outcome description refer to different counts; the record does not explain the distinction.
Intervention
The imaging approach was molecular breast imaging (MBI) using 4 mCi of Tc-99m sestamibi. The stated objective also considered whether Wide Beam Reconstruction processing was applied. The registry arm description refers to MBI at 4 mCi and 8 mCi consecutively, but does not give separate outcome results according to reconstruction processing.
Comparator
The intended comparator was standard MBI using 8 mCi of Tc-99m sestamibi. The record describes one group and does not describe randomized allocation or separate parallel groups. It therefore does not establish a randomized comparison between independent groups.
Primary question
The stated question was whether half-dose MBI could achieve image quality and diagnostic accuracy non-inferior to standard-dose MBI. The primary outcome is described as a number of cancers detected. The registry record does not report the detected-cancer counts, an estimate of the difference between doses, a confidence interval, or a non-inferiority margin. Consequently, the stated question cannot be answered from the registry results.
3. Trial Design
This completed study was a single-group diagnostic-imaging evaluation sponsored by Mayo Clinic. The registry lists 83 participants enrolled and identifies breast cancer as the condition. The study began in 2012-07, reached primary completion in 2016-05, and is marked completed. It is listed as not applicable for phase, with no allocation and no masking. Those registry entries do not describe a randomized, blinded, parallel-group treatment trial.
The arm description states that molecular breast imaging was performed at 4 mCi and 8 mCi consecutively. The objective frames 4 mCi as the half-dose approach and 8 mCi as standard MBI, using Tc-99m sestamibi. Wide Beam Reconstruction processing is part of the objective, which asks whether the lower-dose imaging, with or without that processing, can achieve image quality and diagnostic accuracy non-inferior to standard MBI. The record does not specify the exact sequence of procedures, whether every participant received both processing approaches, or how reconstruction conditions were assigned.
The design matters to interpretation. A single-group study that obtains imaging at different doses is not equivalent to a randomized comparison of separate groups. If the same participants contributed images at both doses, the observations would be related within participant; that relationship should be accounted for in the analysis. The record does not report the analysis method or clarify the analysis population in enough detail to determine how that issue was handled.
The primary outcome timeframe is described as at the time of study, within 2 days after the exam, and when enrollment had been reached, approximately 24 months. The registry lists one outcome measure and no analyses. It gives no reported outcome values, analysis results, or explanation of how the two stated timing descriptions relate to each other. The study's planned sample-size justification and detailed statistical plan are not reported in the registry record.
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: 83 subjects were enrolled (consented) but 1 subject was found not to meet eligibility criteria, so did not participate in the study.
Overall Study
| Stage | Molecular Breast Imaging |
|---|---|
| STARTED | 82 |
| COMPLETED | 82 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Of 82 patients recruited to the study (prior to breast biopsy), 34 had a histologically-proven diagnosis of breast cancer.
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 | Molecular Breast Imaging |
|---|---|---|
| Participants analysed | 82 | |
| Age, Continuous | years | 57 (SD 11.3) |
| Sex: Female, Male: Female | Participants | 82 |
| Sex: Female, Male: Male | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 82 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United States | Participants | 82 |
6. Primary Endpoint
The registry lists the primary outcome as Compare the Diagnostic Accuracy of 8 mCi Molecular Breast Imaging (MBI) With 4 mCi MBI., measured over At time of study (within 2 days after exam) and when enrollment has been reached (approximately 24 months).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | cancers detected |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is described as the number of cancers detected when comparing MBI performed with 8 mCi against MBI performed with 4 mCi. This is a count outcome: it records how many cancers were identified, rather than directly reporting a probability of detection, a sensitivity, or a difference in image-quality scores. The outcome description notes that 34 of 82 recruited patients had a histologically proven breast cancer diagnosis before breast biopsy was referenced in the enrollment description.
Cancer detection is relevant to the objective because the study asks whether lower-dose imaging can preserve diagnostic accuracy. However, a count by itself is difficult to interpret without the corresponding detection results for each dose, the number of eligible cancers assessed by each method, and information about cancers not detected. The registry record does not report those data or the numerical outcome result. It also does not report a definition of the image-quality measure or a threshold for deciding that the lower dose is non-inferior.
In general, diagnostic accuracy describes how well a test distinguishes people with and without the condition of interest against a reference standard. Counts of detected cancers can contribute to that assessment, but do not by themselves give the full diagnostic-accuracy picture. The registry record does not report the false-positive results, the full reference-standard classification, or a detailed accuracy analysis. Therefore, the endpoint's stated purpose is clear, but its observed value and its precision cannot be assessed from this record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record states a diagnostic objective, not a numerical finding. It describes a comparison of MBI at 4 mCi with MBI at 8 mCi and identifies the primary measure as the number of cancers detected. However, it does not report the cancer counts for either dose, a difference or other comparative estimate, a confidence interval, or a p-value. Without those results, there is no basis in the record to describe the observed direction or size of any dose-related difference.
The objective uses the term non-inferior. In general, a non-inferiority study asks whether the experimental approach is not worse than a comparator by more than a prespecified, clinically acceptable margin. Such a conclusion requires a defined margin and an estimate with sufficient precision relative to that margin. The registry record does not report the margin, the analysis used to assess it, or a confidence interval. The stated aim alone is not evidence that non-inferiority was demonstrated.
The record describes 82 recruited patients in the primary outcome population, of whom 34 had a histologically proven breast cancer diagnosis. It separately lists enrollment as 83. The reason for the difference is not reported in the registry record. These counts should not be treated as interchangeable denominators without knowing which participants contributed usable images, which were included in the cancer-detection analysis, and how the analysis population was defined.
There is also a design limitation relevant to comparison. The study is listed as single-group, with no allocation, and describes imaging at the two doses consecutively. It is not a like-for-like randomized control comparison. If the same patients contributed results at both doses, within-person dependence would matter for uncertainty estimates; the registry record does not report how that dependence was handled. The record also does not state how Wide Beam Reconstruction conditions were compared or whether results were separated by processing approach.
Consequently, the posted information supports a description of what the study set out to evaluate and how the registry characterizes its design. It does not support a quantitative judgment about relative cancer detection, diagnostic accuracy, image quality, or the precision of those measures. No conclusion about the study's primary objective can be drawn from the registry record alone.
9. Statistical Methods Explained
Interpreting this study requires separating the scientific question from the evidence needed to answer it. The question concerns diagnostic performance at two imaging doses, while the registry reports a count outcome but no numerical result. General statistical concepts can clarify what would be needed for interpretation, but they cannot replace the absent study results.
What does non-inferiority mean?
In general, non-inferiority is a prespecified comparison framework. It does not mean that two methods have identical results, nor does a non-significant difference by itself establish non-inferiority. Investigators ordinarily define a margin representing the largest loss in performance that would still be considered acceptable for the study question. The estimated difference and its uncertainty are then evaluated relative to that margin. A confidence interval expresses a range of values compatible with the data under the analysis assumptions. For a non-inferiority conclusion, that interval must be sufficiently precise in relation to the chosen margin.
The registry record states a non-inferiority objective but does not report a margin, an effect estimate, a confidence interval, or a test result. It is therefore not possible to determine whether the data met a non-inferiority criterion. The objective should be read as the question the study intended to examine, not as a result.
How should a count outcome be understood?
The primary measure is the number of cancers detected. A count is an absolute tally, but it needs a meaningful denominator and a clear definition of which cases could have been detected. For diagnostic accuracy, the analysis generally needs to distinguish cases with disease from those without disease and compare imaging classifications with an appropriate reference standard. Sensitivity concerns detection among people who have the condition; specificity concerns correct negative classifications among people who do not. These are general definitions, not results reported for this study.
The record says that 34 patients had histologically proven breast cancer, but gives no detected-cancer counts by dose and no corresponding accuracy estimates. It does not report false-positive classifications or a complete account of reference-standard status. A cancer-detection count alone therefore cannot establish the full diagnostic performance of either imaging dose.
Why does the study structure matter?
The registry identifies a single group and describes MBI at both 4 mCi and 8 mCi consecutively. If the same participant underwent imaging at both doses, the two observations are paired rather than independent. In general, paired analyses use the within-participant relationship to estimate a comparison and its uncertainty. Treating paired observations as if they came from unrelated participants can misstate precision. The registry record does not report whether all participants had both examinations or how the analysis handled any pairing.
The study is not described as randomized, and its allocation is listed as not applicable. That means the record does not support interpreting it as a randomized comparison of separate arms. The procedure order, any order effects, and the handling of Wide Beam Reconstruction are not reported. These design details matter because imaging conditions and analysis choices can affect comparability.
What can precision measures contribute?
In general, a point estimate describes the observed comparison, while a confidence interval communicates how uncertain that estimate is. A narrow interval indicates greater precision under the model assumptions; a wide interval indicates that a range of effects remains compatible with the data. A p-value, when used, addresses compatibility with a specified statistical null hypothesis and does not measure clinical importance or prove equivalence. None of these numerical results is reported for the primary comparison in the registry record.
Counts can also show variability beyond what a simple statistical model expects. In general, over-dispersion means observed variation is greater than the model allows. If present, it can make standard errors too small and confidence intervals too narrow under an inadequately specified model. The record does not report a count model, an over-dispersion assessment, or any other analysis method, so no particular modeling approach can be attributed to this study.
What do the planning assumptions mean?
A planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a stated fraction of the observed effect. These are assumptions for a planning calculation, not evidence about how the study itself was designed or analyzed. The registry does not report the trial's own sample-size justification. A planning sample size is not observed power and does not show that an analysis had a particular probability of detecting an effect after the study was completed.
For non-time-to-event outcomes, a planning quantity expressed as participants per arm is a hypothetical design requirement under its assumptions; it is not the number enrolled in this single-group study. Such an illustration also cannot supply missing outcome data or establish non-inferiority. Since the registry record does not report the observed effect or comparative result, the planning assumptions should not be mistaken for a finding about MBI.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and no analyses. That does not establish that the study used only one statistical test: the record does not report a complete analysis plan, all endpoints considered, or all comparisons performed. The primary objective includes image quality and diagnostic accuracy, and it refers to lower-dose imaging with or without Wide Beam Reconstruction. Whether these were treated as separate comparisons, how outcomes were prioritized, and whether any adjustment for multiple testing was planned are not reported in the registry record.
Multiplicity matters in general when several outcomes, subgroups, processing conditions, or comparisons are examined. Repeated testing can increase the chance of finding an apparently notable result by chance if the analysis does not account for the broader set of tests. Without the analysis plan and reported analyses, it is not possible to assess how this issue was addressed for this study.
The record does not describe missing-data procedures, exclusions after enrollment, handling of uninterpretable images, or the analysis population used for the primary outcome. It reports enrollment of 83, while the primary outcome description refers to 82 recruited patients and identifies 34 with histologically proven breast cancer. The reason for these different counts is not reported in the registry record. It is also not stated whether the outcome population included all enrolled participants, only those with evaluable imaging, or a subset defined by confirmed disease status.
These omissions limit interpretation because exclusions and missing imaging or reference-standard information can affect the denominator and the resulting accuracy estimates. The registry record does not report enough information to evaluate those potential effects or to determine whether the analysis followed a prespecified plan.
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 |
|---|---|---|---|
| Molecular Breast Imaging | 0 | 82 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Molecular Breast Imaging | 0 of 82 |
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 |
|---|---|
| Molecular Breast Imaging | 0 of 82 |
The registry lists 82 participants at risk in the molecular breast imaging group. It reports zero participants affected by serious adverse events, zero affected by other adverse events, and zero deaths. These are the posted safety figures for the group; they are not comparative safety estimates between randomized arms, because the registry describes a single-group study rather than randomized allocation.
A zero count in a registry record means that no events are reported for the specified category and group. It does not prove that an event is impossible or that the intervention has no risk. In general, the interpretation of adverse-event counts depends on how events were defined, how they were collected, the duration of follow-up, and whether all participants had complete safety information. Those details are not reported in the registry record. The record also does not list serious adverse-event terms, consistent with no serious terms being posted.
The figures should be read as a description of events recorded in this study, not as a precise estimate of risk for other populations or settings. The record does not provide a comparison group or a detailed safety analysis. No causal conclusion about the imaging procedure can be drawn from these counts alone.
12. What the Result Does, and Does Not, Mean
The study's scientific aim was to examine whether MBI at 4 mCi, with or without Wide Beam Reconstruction, could achieve image quality and diagnostic accuracy non-inferior to standard MBI at 8 mCi. The registry identifies the primary measure as cancers detected and describes a group receiving imaging at both dose levels consecutively. This establishes the subject of the evaluation, but the registry does not report the results required to assess the objective.
The record gives context for the target population: 82 patients are mentioned in the primary outcome description, and 34 of them had histologically proven breast cancer. The overall enrollment is listed as 83. It does not report why these counts differ, how many cancers were detected at each dose, or the full diagnostic-accuracy results. Without those details, the magnitude and precision of any comparison cannot be described.
In general, evidence of non-inferiority requires a defined margin, a suitable comparison, and a sufficiently precise estimate evaluated against that margin. The registry record does not report the margin or the comparison estimate. It therefore does not show that the lower-dose approach met the stated objective, and it also does not show that it failed to meet it. The result is unreported, rather than established in either direction.
The single-group structure is also important. The record does not describe randomized allocation, and it does not provide enough detail to assess how paired observations, procedure order, or reconstruction conditions were handled. These features affect what can be inferred from any comparison, even if numerical results are available.
The appropriate reading is therefore limited: NCT01653964 was a completed evaluation of diagnostic imaging at two stated doses, with an objective framed around non-inferiority. Its posted registry information does not permit a quantitative conclusion about cancer detection, image quality, diagnostic accuracy, or the comparative precision of the two dose approaches.
13. Why This Trial Matters Statistically
This study raises a useful statistical distinction between having a clear research question and having enough reported evidence to answer it. The objective is stated in terms of non-inferiority, a framework that depends on a prespecified margin and a precise estimate. The registry record does not report either the margin or the comparative estimate. As a result, the intended question is visible, but the evidential basis for a conclusion is not.
The design also illustrates why the unit of comparison matters. The study is described as a single group undergoing MBI at two doses consecutively, rather than as a randomized comparison of separate groups. If observations are paired within participants, the analysis should reflect their dependence. A result's uncertainty can differ depending on whether that structure is recognized. The record does not state how the data were analyzed.
Diagnostic accuracy is more demanding than reporting a tally of detected cancers. A detection count needs context about the number and status of cases assessed, the reference standard, and missed or false-positive classifications. The outcome description notes histologically proven cancer in some patients, but the registry does not post the dose-specific detection counts or the other details needed to interpret accuracy.
Finally, the record distinguishes enrollment from the count in the primary outcome description without explaining the difference. Clear accounting of analysis populations and missing observations is important for understanding denominators and possible selection effects. These statistical issues are not unique to imaging studies: they apply broadly to paired diagnostic evaluations and non-inferiority claims. In this record, they identify what additional reporting would be needed for a complete assessment, not what the study results were.
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 leaves several trial-specific details unresolved. It lists enrollment as 83, while the primary outcome description refers to 82 patients recruited before breast biopsy. It does not explain whether the counts reflect eligibility, participation in imaging, evaluable examinations, or another distinction. Without that accounting, the analysis denominator cannot be established.
The arm description says that MBI at 4 mCi and 8 mCi was performed consecutively, but does not specify procedure order, whether every participant received both examinations, or the handling of any incomplete or uninterpretable scans. Because the study is single-group, these details are important for understanding the comparison. The record also does not explain how Wide Beam Reconstruction was applied or how results were separated by reconstruction condition.
The registry does not report cancer-detection results, diagnostic-accuracy estimates, image-quality results, confidence intervals, or statistical tests. It does not state the non-inferiority margin, the sample-size justification, the analysis population, the missing-data approach, or the statistical model. These omissions prevent assessment of the primary objective and of the precision of any comparison.
The record provides limited safety detail beyond event counts: definitions, collection methods, and follow-up procedures are not reported in the registry record. The timing description for the primary outcome refers both to within 2 days after the exam and to when enrollment had been reached, approximately 24 months; how those timing statements fit together is not explained. These limitations concern the information available in the registry record and do not establish that the study itself lacked additional methods or findings.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluation of Half-Dose Molecular Breast Imaging With Wide Beam Reconstruction Processing — NCT01653964.
- Registry record last updated 2017-09-18; status last verified 2017-09.
- Results first posted 2017-09-18.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT01653964, titled Evaluation of Half-Dose Molecular Breast Imaging With Wide Beam Reconstruction Processing, is listed as a completed, single-group diagnostic-test study sponsored by Mayo Clinic. It enrolled 83 participants, with a start date of 2012-07 and primary completion in 2016-05. The study evaluated molecular breast imaging at 4 mCi and 8 mCi of Tc-99m sestamibi. Its stated objective was to assess whether half-dose MBI, with or without Wide Beam Reconstruction, could achieve image quality and diagnostic accuracy non-inferior to standard MBI.
The primary outcome is described as the number of cancers detected. Its population description refers to 82 patients, including 34 with histologically proven breast cancer. The registry reports no analyses and does not post primary comparative results, a non-inferiority margin, or a detailed statistical plan. It lists zero serious adverse events, zero other adverse events, and zero deaths among 82 participants at risk. The available record describes the study objective and design but does not allow the primary comparison to be evaluated.