Novel in Vivo Synaptic Imaging in Experienced Meditators: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Novel in Vivo Synaptic Imaging in Experienced Meditators (NCT05418608), a na phase 1 study. The primary outcome is Binding Potential Using Synaptic Density.

2. Clinical Question

3. Trial Design

The registry identifies NCT05418608 as a completed Phase 1 study sponsored by Yale University. The listed enrollment is 40. The study began on 2022-04-21, and primary completion is listed as 2024-04-01. The record names the condition areas as Behavior and Health.

The description centers on PET imaging with [11C]UCB-J, a tracer used to characterize binding in cortical and subcortical brain regions, with MRI used for anatomical identification. The meditator and non-meditating-control descriptions each refer to a PET scan and an MRI scan. The stated objective compares tracer distribution between experienced meditators and non-meditating controls.

There is an important design qualification: the registry lists the model as single-group, allocation as not applicable, and masking as none. It also explicitly says this is not a randomized comparison and that the arms are not a like-for-like control comparison. Accordingly, the group labels and intended contrast should not be interpreted as evidence of randomized assignment or of a controlled treatment effect. The registry record does not explain how the single-group classification relates to the two group descriptions.

The record lists one primary imaging outcome and a secondary outcome concerning correlation between meditation questionnaire data and SV2A binding. It contains no recorded statistical analyses. Numerical primary and secondary outcome findings, group characteristics, and details of any analysis population 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.

Overall Study

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.

6. Primary Endpoint

The registry lists the primary outcome as Binding Potential Using Synaptic Density, measured over Up to 6 months.

The primary outcome is titled “Binding Potential Using Synaptic Density.” The registry describes binding potential as a unitless measure and reports that values for each region represent binding potential. It is intended to characterize [11C]UCB-J tracer binding across brain regions, as part of an assessment of synaptic density.

The endpoint is continuous, with the planned summary parameter identified as a mean and dispersion identified as standard deviation. The timeframe is “Up to 6 months.” The outcome description says imaging data were analyzed using kinetic modeling to quantify total tracer binding, volume of distribution, and binding potential. It specifies voxel-by-voxel compartment model fitting with an arterial input function.

Regional measurement matters because tracer binding may be characterized separately across cortical and subcortical areas rather than reduced to one whole-brain value. The described processing registers PET images to each subject’s T1-weighted MR images and then to an MR template. Gray matter regions of interest are determined using template-defined regions with a gray matter segmentation mask, and partial volume correction is applied to account for atrophy. These procedures describe how the endpoint was intended to be derived; they do not establish the result. Numerical means, standard deviations, and regional estimates are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a continuous imaging outcome summarized as a mean with standard deviation. It also gives a detailed account of image processing and kinetic modeling. The explanations below distinguish those recorded methods from general statistical interpretation. Numerical outcome estimates and inferential analyses are not reported in the registry record.

What does a mean with standard deviation describe?

The mean is a summary of the central value of a continuous measurement. The standard deviation describes how dispersed individual measurements are around that mean. These quantities answer different questions: the mean describes the group’s average level, while the standard deviation describes variability among measured values. A standard deviation is not the same as the uncertainty in an estimated mean. A confidence interval, when reported, expresses uncertainty around an estimate under the assumptions of the analysis. No means, standard deviations, or confidence intervals for binding potential are reported in the registry record.

How is binding potential derived?

The endpoint description says that PET data were analyzed using kinetic modeling to quantify total tracer binding, volume of distribution, and binding potential. It specifies voxel-by-voxel compartment model fitting with the arterial input function. In general, kinetic models use the time course of tracer measurements and a model of tracer movement to estimate quantities that cannot be read directly from a single image. The registry’s description identifies the modeling approach but does not report fitted values, model diagnostics, or uncertainty for those estimates.

Why are image registration and regions of interest used?

The stated processing registers PET images to a subject’s T1-weighted MR images and then to an MR template. In general, registration aligns images so that anatomical locations can be compared or summarized consistently. The record describes gray matter regions of interest as template-defined regions combined with a gray matter segmentation mask. It names FreeSurfer for the template regions and the FAST algorithm in FSL for segmentation. This process is described as enabling automatic determination of regional outcome values. It does not, on its own, show how similar the groups were or establish a causal effect.

What does partial volume correction address?

The registry says partial volume correction is applied to account for atrophy. In general, partial volume effects occur when the spatial resolution of imaging causes signals from nearby tissues or structures to blend. Correction methods attempt to address this mixing when estimating regional signal. Such correction depends on modeling and image-processing choices; the record does not report sensitivity analyses or the impact of this step on the outcome estimates.

Why does design affect the statistical interpretation?

In general, random allocation can help balance measured and unmeasured characteristics between groups, while observational group comparisons can remain vulnerable to confounding. This study is listed as single-group, with allocation not applicable and no masking. The registry explicitly states that the arms are not a like-for-like control comparison. Thus, the record does not support treating a group contrast as a randomized treatment effect. The registry does not report how groups were selected, whether covariates were adjusted for, or a statistical model for a between-group estimate.

What can be said about statistical significance and precision?

A p-value, when reported, describes how compatible data are with a specified null model under the analysis assumptions; it is not a measure of the size or practical importance of an effect. A confidence interval communicates uncertainty about an estimate and its plausible values under the method used. Neither a p-value nor a confidence interval for the primary endpoint is reported in the registry record. Because the numerical estimates are also absent, the direction, size, and precision of the primary outcome cannot be assessed from this record.

How should planning calculations be read?

In general, sample-size calculations are planning illustrations based on assumptions about an effect, variability, allocation, and the chosen statistical test. They are not observed power and cannot substitute for an outcome estimate or confidence interval. Any illustration based on a fraction of an observed effect depends on that observed effect being available and on the calculation assumptions. The registry record does not report primary outcome estimates or a trial-specific design justification, so a planning calculation cannot resolve the missing results or establish what the study was designed to detect.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists the primary binding-potential outcome and a secondary outcome concerning correlation between meditation questionnaire data and SV2A binding. It does not report whether additional regional or other outcomes were analyzed beyond the listed measures, how many statistical tests were conducted, or whether any adjustment for multiple comparisons was planned or used. A multiplicity strategy is therefore not reported in the registry record.

Multiplicity matters in general when many outcomes, regions, or comparisons are tested: considering more tests can increase the chance of obtaining apparently notable results by chance. Adjustments and prespecified analysis choices can help readers understand how findings were evaluated. Since no numerical outcome analyses or p-values are recorded, the consequences of multiplicity cannot be assessed for this study.

Missing-data methods are not reported in the registry record. The record does not state how missing PET or MRI measurements, incomplete scans, unavailable questionnaire responses, or exclusions from analysis were handled. It also does not specify the analysis population or provide participant flow through screening, enrollment, imaging, and analysis. The enrollment figure alone does not establish how many participants contributed to any particular endpoint.

The registry lists zero analyses. This means no analysis entries are present in the record; it should not be read as proof that no analysis was performed. Without analysis-population details, missing-data handling, or outcome estimates, readers cannot determine whether reported findings, if available elsewhere, reflect all enrolled participants or a selected subset.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports serious and other adverse-event counts separately for Meditators and Non-meditating Controls. For each group, it lists 20 participants at risk for serious events and 20 at risk for other events. The affected counts are 0 for serious events and 0 for other events in each group. Deaths are listed as 0 in each group, and no serious-event terms are listed.

These are the safety counts recorded in the registry, not estimates of comparative risk. The study is not described as a randomized comparison, and the registry says the arms are not a like-for-like control comparison. The counts therefore should not be used to infer that one group had lower risk than the other or that the imaging procedures have no risk.

Zero recorded affected participants means that the registry lists no events in these categories for the reported groups. It does not establish that every possible adverse experience was measured or that events could not occur. The record does not report details of safety surveillance, event definitions, duration of follow-up for safety, or whether any events were missing from reporting. These qualifications matter when interpreting a zero count.

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

The result that can be stated from the registry is primarily methodological: the study aimed to characterize [11C]UCB-J binding potential in brain regions among experienced meditators in relation to non-meditating controls. The endpoint is described as a unitless continuous measure derived from PET imaging and kinetic modeling, with MRI-based anatomical processing and partial volume correction.

The record does not provide numerical binding-potential findings. It therefore does not show the average regional values, variability, size or direction of a group contrast, or precision of any estimate. Nor does it report a result for the secondary questionnaire-correlation outcome. The lack of these estimates is not evidence that the groups had identical measurements or that a meaningful difference was found; the registry record does not allow either conclusion.

The design description also calls for caution. The intended scientific comparison is between meditators and non-meditating controls, but the registry classifies the study as single-group and says the arms are not a like-for-like control comparison. It lists no random allocation. Any apparent contrast would need to be interpreted in light of participant selection and group comparability, details that are not reported in the registry record.

In general, imaging measures provide an operational way to quantify a biological signal, but they should not be equated automatically with a broad clinical outcome. The record focuses on tracer distribution and binding potential; it does not report clinical benefits, changes in health, or evidence that meditation caused any imaging difference. The posted safety counts list zero affected participants in the recorded adverse-event categories, but those counts do not establish absence of all possible harm.

13. Why This Trial Matters Statistically

This study is statistically notable for the way it connects a specialized imaging endpoint with a group-based research question. The registry describes PET kinetic modeling, an arterial input function, regional analysis, MRI registration, gray matter segmentation, and partial volume correction. Such processing illustrates that an imaging endpoint is not simply a raw scanner reading: it depends on measurement and modeling choices that shape the estimate.

The record also highlights why study design labels and outcome reporting need to be read together. The scientific aim refers to meditators and non-meditating controls, while the registry classifies the model as single-group and explicitly cautions that the arms are not a like-for-like control comparison. This makes it especially important to distinguish a descriptive group contrast from a randomized causal comparison.

For statistical interpretation, the absence of numerical results is decisive. Without regional means, variability, contrasts, or uncertainty intervals, the size and precision of the primary endpoint cannot be evaluated. The registry’s description of methods is useful for understanding how the outcome was intended to be constructed, but methods alone do not reveal what was observed. Likewise, zero recorded adverse events in the listed categories is a report about the recorded counts, not a general proof of safety.

The record therefore provides a useful case for separating three questions: what was measured, how it was measured, and what the data show. Here the first two are described in some detail, while numerical answers to the third are not reported in the registry record.

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 interpreting results is that numerical primary and secondary outcome estimates are not reported in the registry record. There are no regional means or standard deviations, group contrasts, confidence intervals, or p-values available for assessing magnitude, direction, or precision. The registry lists zero analyses, but that does not establish whether analyses were conducted outside the record.

There is also an unresolved design description. The stated aim compares experienced meditators with non-meditating controls, yet the registry identifies the model as single-group, lists allocation as not applicable, and says the arms are not a like-for-like control comparison. The record does not explain the classification or report group-selection methods, baseline characteristics, or adjustment for potential confounding. These omissions limit interpretation of any between-group contrast.

The registry does not report detailed eligibility criteria or how meditation experience was operationalized. It also does not provide participant flow, the analysis population, missing-data handling, or exclusions for the primary imaging outcome. The listed enrollment should not be assumed to equal the number contributing to each regional estimate.

Although the outcome description gives substantial image-processing detail, the record does not report model diagnostics, sensitivity analyses, or the influence of the described partial volume correction. It also does not report a multiplicity plan for evaluating multiple regions or outcomes. These gaps prevent assessment of how robust any potential findings would be to analysis choices. Finally, the safety counts are registry entries without accompanying details about event definitions, surveillance, or follow-up for safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Novel in Vivo Synaptic Imaging in Experienced Meditators — NCT05418608.
• Registry record last updated 2026-06-10; status last verified 2026-05.
• Results first posted 2026-06-10.
• 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.

18. Record Summary

NCT05418608 is a completed Phase 1 imaging study sponsored by Yale University, with enrollment listed as 40. The record gives a start date of 2022-04-21 and a primary completion date of 2024-04-01. Its stated objective is to characterize [11C]UCB-J PET binding in cortical and subcortical areas in experienced meditators in relation to non-meditating controls.

The primary endpoint is regional binding potential, described as a unitless continuous measure summarized by a mean and standard deviation. The record describes kinetic modeling, MRI registration, gray matter regions of interest, and partial volume correction. It also lists a secondary questionnaire-correlation outcome.

The registry classifies the design as single-group and says the arms are not a like-for-like control comparison. Numerical primary and secondary results, analysis details, missing-data methods, and multiplicity procedures are not reported in the registry record. Recorded serious and other adverse-event counts are zero in both groups.