Development of Radiation Free Whole Body Magnetic Resonance (MR) Imaging Technique for Staging Children With Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Development of Radiation Free Whole Body Magnetic Resonance (MR) Imaging Technique for Staging Children With Cancer (NCT01542879), a na phase 1, phase 2 study. The primary outcome is Sensitivity and Specificity of WB-DW-MR Compared to 18F-FDG PET/CT.

2. Clinical Question

This is a diagnostic-imaging question, not a randomized treatment-effect question. The registry record describes a single-group study, so its design does not assign participants to randomized imaging groups. The purpose stated in the study summary is to evaluate newer whole-body imaging techniques, including their ability to detect the extent and spread of disease. The rationale includes the possibility of no or reduced radiation exposure compared with standard CT and PET/CT imaging, but the rationale is not itself evidence of diagnostic performance or radiation outcomes.

3. Trial Design

The registry record describes a completed Phase I and Phase II study sponsored by Stanford University. It lists a single-group model, allocation as not applicable, and no masking. Enrollment is recorded as 158. The study began on 2012-02-22, and its primary completion date is 2022-08-08. These registry entries describe the study structure and timing; they do not establish what imaging procedures every participant completed or how the images were analyzed.

The arm description is a simultaneous WB-DW-MR scan and 18-F FDG PET scan. The interventions listed in the record are WB-DW-MR scan, 18-F-FDG PET scan, ferumoxytol, and 18-F-FDG PET/MR scan. The primary outcome is framed as a comparison of WB-DW-MR with standard 18F-FDG PET/CT. The study summary additionally describes standard MR, CT, PET, bone, and MIBG imaging as tests used to determine disease extent. Details about the sequence of imaging, which participants received PET/MR or ferumoxytol, and how the different modalities were linked in the analysis are not reported in the registry record.

This is not a randomized comparison: the registry record lists no allocation and a single-group design. The imaging modalities may be compared for diagnostic accuracy, but the record does not describe independent randomized groups or a like-for-like control arm. The primary endpoint timeframe is 3 to 14 weeks post-treatment, with the interval determined by tumor type and treatment protocol. The protocol details behind those intervals are not reported in the registry record. The record does not report a sample-size justification, interim-analysis plan, or a full statistical analysis plan.

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 Sensitivity and Specificity of WB-DW-MR Compared to 18F-FDG PET/CT, measured over 3 to 14 weeks post-treatment (interval determined by tumor type and treatment protocol).

The primary outcome is titled sensitivity and specificity of WB-DW-MR compared with 18F-FDG PET/CT. Sensitivity is the true-positive rate: among cases that meet the reference standard for tumor detection or the relevant clinical finding, it describes how often the imaging test identifies that finding. Specificity is the true-negative rate: among cases that do not meet the reference standard, it describes how often the test classifies them as negative. These are general definitions of diagnostic-accuracy measures.

The registry description says the imaging findings are compared with a clinical reference standard based on biopsy and/or follow-up imaging. A reference standard is needed because diagnostic accuracy depends on how the underlying condition or finding is established. The record does not specify how decisions between biopsy and follow-up imaging were made, whether the same reference standard was used for every participant, or how uncertain or unavailable reference results were handled.

The endpoint is expressed as a percentage with a 95% confidence interval. A confidence interval describes the uncertainty around an estimated quantity; its width depends on the information available and the analysis. The registry record does not report the observed sensitivity, specificity, or confidence intervals. It therefore does not permit a numerical reading of diagnostic accuracy or precision. The stated assessment window is 3 to 14 weeks post-treatment, with the interval determined by tumor type and treatment protocol.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What do sensitivity and specificity describe?

In general, sensitivity and specificity summarize different aspects of a diagnostic test against a reference standard. Sensitivity concerns detection among reference-standard-positive cases; specificity concerns correct classification among reference-standard-negative cases. They are not interchangeable, and neither alone gives a complete account of how a test performs in a clinical setting. The registry record identifies these measures as the primary outcome for WB-DW-MR compared with standard 18F-FDG PET/CT, using biopsy and/or follow-up imaging as the clinical reference standard. The actual estimates are not reported in the registry record.

Why does the reference standard matter?

In general, estimated diagnostic accuracy depends on how the reference standard classifies each finding. If biopsy is used for some assessments and follow-up imaging for others, the rules for choosing and interpreting those sources can affect which cases count as positive or negative. The registry description names biopsy and/or follow-up imaging, but the criteria for using them, the adjudication process, and handling of inconclusive results are not reported in the registry record. Without those details, readers cannot determine how uniformly the reference standard was applied.

How should a confidence interval be read?

In general, a confidence interval conveys uncertainty around an estimated parameter. A narrow interval indicates greater precision than a wide interval, under the assumptions of the method used. It does not resolve possible bias in participant selection, image interpretation, or reference-standard assessment. The registry outcome specifies a 95% confidence interval for sensitivity and specificity, but no interval limits or estimates are reported in the registry record. Their precision therefore cannot be assessed from the record.

What does the design imply for comparison?

The registry record lists a single-group model, allocation as not applicable, and no masking. This does not describe a randomized imaging comparison. In general, diagnostic modalities may be compared using results from the same participants, but that requires the relevant tests and reference assessments to be available and analyzed in a clearly defined way. Whether the primary analysis was paired, whether every participant received the relevant tests, and how within-participant dependence was handled are not reported in the registry record. The arm description specifies simultaneous WB-DW-MR and 18-F FDG PET, while the primary outcome identifies 18F-FDG PET/CT as comparator; the precise relationship between these procedures in the analysis is not stated.

What is over-dispersion, and is it relevant?

In general, over-dispersion occurs when observed variability exceeds what a statistical model assumes. When present, it can make standard errors too small and confidence intervals too narrow if the model does not account for the extra variability. The registry record does not identify a count model, a dispersion assessment, or a statistical method for the primary diagnostic-accuracy analysis. Over-dispersion is therefore a general statistical consideration, not a reported feature of this study’s analysis.

What can be inferred from the analysis count?

The record lists four outcome measures and one analysis. Those administrative counts do not reveal whether the analysis involved multiple endpoints, subgroups, or repeated measurements, nor do they establish how outcomes were prioritized in practice. The method used to estimate sensitivity and specificity, the unit of analysis, any adjustment for multiple comparisons, and any subgroup analyses are not reported in the registry record. No statistical plan should be inferred from the number of analyses listed.

How should planning illustrations be interpreted?

The planning illustrations are described as calculations based on the observed effect, not as the trial’s own design. Their stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event calculations, the quantity is a total event count using the Schoenfeld approach; for other calculations, it is participants per arm. These are planning illustrations, not observed power and not evidence that the completed single-group study was designed with those assumptions. The registry record does not report that these were the trial’s protocol assumptions, and they should not be treated as the study’s sample-size justification.

More broadly, statistical methods are needed to connect collected observations to estimates and uncertainty. For this study, the posted registry information defines the endpoint and confidence-interval format but does not report the underlying estimates or enough analytic detail to reproduce them. The analysis population, missing-data procedures, and rules for excluding or classifying results are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists four outcome measures and one analysis, but it does not report a multiplicity strategy. Multiple outcomes or repeated comparisons can create more opportunities for an apparently notable finding by chance; statistical methods may address that issue by adjusting inference or by defining a primary outcome in advance. The record identifies a primary endpoint, but whether any adjustment was used for additional outcomes or analyses is not reported in the registry record. The listed outcome and analysis counts do not establish that multiplicity was absent or controlled.

Missing-data methods are not reported in the registry record. This includes how incomplete imaging, missing reference-standard assessments, uninterpretable scans, or participants without follow-up were handled. The registry enrollment of 158 does not establish the number included in the primary diagnostic-accuracy analysis. The numbers with evaluable WB-DW-MR, comparator imaging, and reference-standard results are not reported in the registry record.

Analysis-population definitions are also not reported in the registry record. It is unclear whether the primary analysis included all enrolled participants, only those with technically adequate images, or a subset with complete assessments. The registry does not state how participants with multiple lesions or imaging findings were counted, or whether any clustering was accounted for. These details matter because diagnostic-accuracy estimates depend on the observations included and the way they are grouped.

The registry record does not report interim analyses, stopping rules, or a full statistical analysis plan. No assumptions about these procedures can be made from the completed status or the number of analyses listed.

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.

Most frequent non-serious adverse event terms

The registry lists the WB-DW-MR Scan group with 158 participants at risk for serious adverse events and zero affected. For other adverse events, it lists 158 at risk and one affected. These are registry counts, not estimates of comparative risk, and the record does not provide event descriptions for the other adverse event. It also lists six deaths in the group.

The death count should be read separately from the adverse-event counts. The registry record does not report the cause or timing of those deaths, whether they were considered related to study procedures, or whether the deaths were counted as adverse events. No serious adverse-event terms are listed. The record also does not report the safety follow-up period or the completeness of event ascertainment.

Because the study is described as a single-group study with no randomized comparator, these figures do not support a comparison of safety between imaging approaches. They are descriptive counts within the recorded group. A zero count of serious events in the registry record does not establish that no event could occur, and the count alone does not characterize the safety of the imaging procedures.

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

The registry record establishes that the study evaluated whole-body imaging in children with cancer and specified sensitivity and specificity of WB-DW-MR compared with standard 18F-FDG PET/CT as its primary outcome. It identifies biopsy and/or follow-up imaging as the reference standard and gives an assessment window of 3 to 14 weeks post-treatment, with timing dependent on tumor type and treatment protocol. It also records enrollment of 158 and a completed status.

What the record does not establish is the observed diagnostic accuracy. The sensitivity and specificity estimates and their 95% confidence intervals are not reported in the registry record. Consequently, readers cannot use this record to judge the magnitude or precision of the primary results, determine whether the modalities performed similarly, or assess whether one was more accurate than the other. No conclusion about diagnostic performance should be inferred from the study’s stated purpose or rationale.

The description of reduced or absent radiation exposure is part of the study rationale, not a reported comparative outcome in the listed primary endpoint. The registry record does not provide quantitative radiation results or a comparison of radiation exposure. Likewise, the single-group design and absence of allocation do not support interpretation as a randomized treatment comparison.

The safety counts describe the events recorded for the WB-DW-MR Scan group, but the record does not provide causal attribution or follow-up details. The counts cannot establish whether an event was caused by an imaging method. In general, a study’s conclusions depend on the completeness of its data, its analysis methods, and the precision of its estimates. Those elements are not fully reported in the registry record. The result that can be read confidently is the registered question and study structure, not a numerical answer to the primary diagnostic-accuracy question.

13. Why This Trial Matters Statistically

Diagnostic imaging studies raise a distinct statistical question from trials that compare treatments: how closely do test classifications align with an appropriate reference standard? Sensitivity and specificity address different types of classification error, and both need to be interpreted alongside their uncertainty and the way the reference standard was applied. This study’s registered primary outcome makes those issues central.

The record also illustrates why design labels matter. It describes a single-group, unmasked study with allocation not applicable, rather than a randomized comparison. That structure does not automatically make diagnostic comparison impossible, but it does mean readers should not interpret the study as assigning participants to competing treatment arms. Understanding how each imaging modality and reference assessment was applied is essential for interpreting a diagnostic comparison.

The stated rationale includes avoiding or reducing radiation exposure relative to standard CT and PET/CT imaging. That is an important context for the imaging question, but the primary outcome is diagnostic accuracy, and the registry record does not report numerical results for it. Separating a study’s motivation from its reported evidence prevents the rationale from being mistaken for a demonstrated outcome.

Finally, the record shows the limits of registry-level interpretation. It records enrollment, design, outcome definitions, and safety counts, yet does not report the primary estimates, confidence intervals, detailed analysis population, or missing-data methods. Statistical interpretation depends not only on naming an endpoint but also on reporting the observations and methods behind its estimate. Without those details, the primary question remains quantitatively unresolved 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 primary limitation for interpretation is that the registry record does not report the sensitivity and specificity estimates or their confidence intervals. As a result, the intended diagnostic-accuracy comparison cannot be quantified from the record. The endpoint description identifies biopsy and/or follow-up imaging as the reference standard but does not explain how the reference was selected, interpreted, or applied across participants.

The design is listed as single-group, unmasked, and with allocation not applicable. The record does not explain which participants underwent each imaging procedure, how WB-DW-MR was compared with 18F-FDG PET/CT, or whether the comparison used assessments from the same participants. It also does not report whether image readers were blinded to other results. These missing details limit assessment of potential sources of bias in diagnostic classification.

The timeframe varies from 3 to 14 weeks post-treatment according to tumor type and treatment protocol. The registry record does not provide the rules governing this variation, or results by tumor type or timing. Eligibility criteria, participant characteristics, evaluable sample sizes for the endpoint, and analysis-population definitions are not reported in the registry record. Therefore, the enrollment figure cannot be assumed to equal the number contributing to each diagnostic-accuracy estimate.

Missing-data handling, multiplicity procedures, and the full statistical analysis plan are not reported in the registry record. The safety information is also limited: causes and timing of deaths, attribution, and the safety follow-up period are not reported. These limitations prevent a complete assessment of the study’s methods and findings based on the registry record alone.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Development of Radiation Free Whole Body Magnetic Resonance (MR) Imaging Technique for Staging Children With Cancer — NCT01542879.
• Registry record last updated 2026-10-06; status last verified 2026-09.
• Results first posted 2026-10-06.
• 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

NCT01542879 is a completed Phase I and Phase II, single-group study sponsored by Stanford University. It enrolled 158 participants and was designed to develop and assess whole-body MR imaging techniques for staging children with cancer. The record lists WB-DW-MR, 18-F-FDG PET, ferumoxytol, and 18-F-FDG PET/MR among the interventions.

The primary outcome is sensitivity and specificity of WB-DW-MR compared with standard 18F-FDG PET/CT, using biopsy and/or follow-up imaging as the clinical reference standard. The assessment timeframe is 3 to 14 weeks post-treatment, depending on tumor type and treatment protocol. The registry record does not report the primary estimates or confidence intervals. Safety counts recorded for the WB-DW-MR Scan group are zero serious adverse events, one other adverse event, and six deaths; event attribution and timing are not reported.