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 Magnetic Resonance Imaging (MRI) of Appendicitis in Children (NCT00723788), a na na study. The primary outcome is Diagnostic Sensitivity/Specificity and Accuracy of Appendiceal MRI Comparedsurgical Findings or Clinical Follow-up.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00723788 |
| Phase | NA |
| Condition | Appendicitis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | Single |
| Enrollment | 21 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Children's National Research Institute |
| Results posted | Yes |
2. Clinical Question
Population
The official title identifies children aged 8–18 being evaluated for appendicitis. The registry lists appendicitis as the condition and describes the primary outcome population as patients who received MRI. Further eligibility criteria and the clinical setting are not reported in the registry record.
Intervention
Participants received MRI of the abdomen, with detailed views of the appendix. The brief summary says the MRI was to be performed without additional contrast material or sedation. The registry describes this as a diagnostic study rather than a treatment comparison.
Comparator
The study aim refers to CT and/or ultrasound performed at the same time as MRI. All patients received MRI; 20 also received ultrasound and 9 received CT, with 8 patients receiving all three procedures. The primary outcome is framed against surgical findings or clinical follow-up, rather than as a randomized comparison between imaging groups.
Primary question
The central question is how well appendiceal MRI classifies appendicitis, using sensitivity, specificity, positive predictive value, and negative predictive value. The brief summary also asks whether MRI can diagnose appendicitis as well as or better than CT and/or ultrasound. Numerical diagnostic estimates and the study’s conclusions are not reported in the registry record.
3. Trial Design
This is a completed, single-group diagnostic study registered as NCT00723788. The registry lists enrollment of 21 and identifies MRI of the abdomen as the only intervention. Every enrolled patient was to receive an abdominal MRI with detailed views of the appendix. The brief summary states that no additional contrast material or sedation would be used for the MRI.
The official title identifies children aged 8–18. The record gives the study start as 2008-08 and primary completion as 2010-04. Its status is completed. Phase and allocation are listed as not applicable, and the model is single group. These fields do not describe a randomized assignment to MRI versus CT or ultrasound.
The record says all patients received MRI; 20 also received ultrasound and 9 received CT, with 8 patients receiving all three procedures. The brief summary frames the aim as evaluating MRI against CT and/or ultrasound performed at the same time. Separately, the primary outcome description refers to comparison with surgical findings or clinical follow-up. The registry does not report the detailed procedures used to establish or adjudicate those reference findings.
Masking is recorded as single, but the identity of the masked party and the practical masking procedures are not reported in the registry record. There is no randomized control arm or like-for-like treatment comparison described. The study therefore addresses diagnostic classification in a group receiving MRI, not a causal treatment effect between assigned imaging strategies. The record’s stated enrollment is a trial characteristic; it should not be read as the number with complete data for every diagnostic measure.
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 | MRI of the Abdomen |
|---|---|
| STARTED | 21 |
| COMPLETED | 21 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: All patients received MRI, of those 20 also received US and 9 CT, meaning that 8 patients received all three procedures.
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.
Population: Patient referral from Emergency Department for suspected appendicitis with ultrasound and/or CT imaging request (0800 hr - 1700 hr)
| Characteristic | Unit | MRI of the Abdomen |
|---|---|---|
| Participants analysed | 21 | |
| Age, Categorical: <=18 years | Participants | 21 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 9 |
| Sex: Female, Male: Male | Participants | 12 |
| Region of Enrollment: United States | participants | 21 |
6. Primary Endpoint
The registry lists the primary outcome as Diagnostic Sensitivity/Specificity and Accuracy of Appendiceal MRI Comparedsurgical Findings or Clinical Follow-up, measured over during diagnostic procedure.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is described as diagnostic sensitivity, specificity, positive predictive value, and negative predictive value for appendiceal MRI, with surgical findings or clinical follow-up named as the basis for comparison. The timeframe is during the diagnostic procedure. The record describes the outcome as a number of participants and classifies it as binary, meaning that the underlying event is a participant count rather than a continuous measurement.
These measures address different aspects of diagnostic classification. In general, sensitivity describes how often a test identifies the condition among those who have it according to a reference standard; specificity describes how often it classifies those without the condition correctly. Positive and negative predictive values describe the probability of the corresponding reference classification among people with positive or negative test results. They complement one another rather than providing interchangeable summaries.
These measures are used because a diagnostic test can have different patterns of classification errors, and one summary alone may not describe that pattern. Predictive values also depend on the composition of the evaluated population, so they should be interpreted in the context of the study population and reference process. The registry lists the intended measures but does not report their numerical estimates, confidence intervals, diagnostic classifications, or detailed reference-standard rules. The endpoint’s planned purpose is clear; its observed diagnostic performance cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a diagnostic aim, not a reported diagnostic result. It names sensitivity, specificity, positive predictive value, and negative predictive value, but gives no numerical estimate for any of these measures. It also does not report confidence intervals or the underlying classification counts. As a result, the posted record does not establish how closely MRI classifications agreed with surgical findings or clinical follow-up.
The record’s brief summary describes a comparison of MRI with CT and/or ultrasound performed at the same time. The primary outcome description, however, identifies surgical findings or clinical follow-up as the reference. These are distinct interpretive questions: comparing imaging tests concerns their relative classifications, while evaluating a test against a reference concerns diagnostic performance relative to that reference. No comparative estimates are reported, so neither question can be answered from the posted results.
The study is single group, and the registry does not describe random allocation to imaging strategies. The fact that some participants also received ultrasound or CT does not by itself make the study a randomized comparison. The timing of tests is described as simultaneous in the brief summary, but details such as reading procedures, blinding of image interpreters, and how discordant assessments were handled are not reported in the registry record.
The enrollment is 21. The record states that all patients received MRI, that 20 also received ultrasound and 9 received CT, and that 8 received all three procedures. These statements describe test receipt, not the number of complete observations available for each diagnostic measure. Whether every participant had an available reference classification, and how missing or indeterminate results were handled, is not reported.
The registry lists no analysis entries. It therefore offers no documented inferential results or analysis details from which to assess precision, adjustment, or robustness. The completed status indicates the study’s registered status, not that outcome estimates are available in this record. In general, a diagnostic estimate is more informative when presented with its denominator, reference definition, and uncertainty; those details are not reported. The appropriate reading is consequently limited: the record documents a planned diagnostic evaluation and participant test receipt, but does not provide the numerical findings needed to judge the accuracy or comparative performance of MRI.
9. Statistical Methods Explained
What does a diagnostic measure summarize?
The listed primary outcome includes sensitivity, specificity, positive predictive value, and negative predictive value. In general, sensitivity and specificity describe classification relative to a reference standard. Sensitivity concerns correct positive classifications among participants with the condition according to that reference; specificity concerns correct negative classifications among participants without it. Predictive values instead start with the test result and describe the reference classification among those with positive or negative results. Each measure answers a different question, so a set of measures can describe diagnostic performance more fully than a single overall accuracy value.
The registry names surgical findings or clinical follow-up as the reference basis. It does not define how those sources were selected, applied, or combined. In general, reference standards matter because a diagnostic measure reflects both the test and the process used to determine the underlying classification. If reference information is unavailable for some participants, or if its application differs across participants, interpretation can be affected. The registry does not report whether these issues arose or how they were addressed.
Why does the reference standard matter?
In general, sensitivity and specificity require classifying participants by both the test being assessed and a reference standard. Predictive values require the same paired information but describe the composition of test-positive and test-negative groups. A transparent report therefore usually identifies the classification rules and the number of participants contributing to each measure. The registry gives the names of the planned measures but not the cross-classification counts, denominators, or estimates. No diagnostic result can be reconstructed from the record’s description of who received which imaging procedures.
The brief summary says MRI was to be assessed against CT and/or ultrasound performed at the same time. Those imaging tests are not necessarily equivalent to the surgical findings or clinical follow-up named in the primary outcome description. In general, a direct comparison between diagnostic tests needs a clear definition of the target comparison and consistent information on how each test was evaluated. The registry does not report comparative test estimates, their uncertainty, or detailed reading and adjudication methods.
What does the single-group design allow?
The study model is single group, and allocation is listed as not applicable. In general, this design can describe diagnostic performance among evaluated participants, provided the test results and reference classifications are reported. It does not create a randomized comparison between imaging strategies. Participants receiving MRI as well as other imaging tests can contribute to paired diagnostic comparisons, but the fact of receiving multiple tests does not establish that a comparative analysis was conducted. The record reports no analyses.
Masking is listed as single. In general, masking can reduce the risk that knowledge of one result influences interpretation of another, but the registry does not identify who was masked or explain how masking was implemented. It also does not report whether images were interpreted independently, whether readers had access to clinical information, or how disagreements were resolved. Those details would help readers assess possible sources of measurement bias.
How should the planning assumptions be read?
The record’s planning assumptions describe an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. The assumptions also distinguish participants per arm for non-time-to-event outcomes from total events for time-to-event outcomes. These are planning conventions, not a description of the registered single-group design or an observed result.
In general, a sample-size calculation asks how much information a future study might need under specified assumptions. Its output depends on the outcome, effect size, variability, allocation, significance criterion, and desired power. A planning illustration is not observed power and does not show that a completed study had adequate precision. No resulting sample-size figures or observed effect are reported in the registry record, and the record does not report the trial’s own sample-size justification. The stated two-arm assumptions should therefore not be mistaken for evidence that this study randomized participants between two arms.
Over-dispersion is a general issue when count variation exceeds what a simple model expects; allowing for it can affect standard errors and interval estimates. The primary outcome is described as participant counts for binary measures, and the registry does not report a statistical model, an over-dispersion assessment, or adjusted analyses. It would be inappropriate to infer that any particular model or correction was used. The record also does not give confidence intervals or p-values, so precision and statistical significance cannot be evaluated from its posted results.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome description lists four related diagnostic measures: sensitivity, specificity, positive predictive value, and negative predictive value. Reporting several measures can be useful because each describes a different feature of classification. At the same time, multiple outcome measures raise questions about which were treated as primary for inference, whether any comparisons were emphasized, and whether adjustments or a prespecified hierarchy were used. Such a multiplicity plan is not reported in the registry record.
The record lists no analysis entries. It does not report an analysis population beyond the outcome description’s reference to all patients receiving MRI, nor does it define a complete-case population or another set of participants for analysis. The number with an available surgical finding or clinical follow-up is not reported. Although the record gives numbers receiving other imaging procedures, those receipt counts do not establish how many participants contributed complete paired data to each diagnostic measure.
Missing-data handling is not reported in the registry record. The record does not state whether missing images, unavailable reference classifications, indeterminate results, or incomplete follow-up occurred. It also does not describe exclusions, imputation, sensitivity analyses, or the handling of participants who could not be classified. These omissions matter because diagnostic estimates depend on which participants are included and how unresolved classifications are treated.
The endpoint timeframe is described as during the diagnostic procedure, but that does not specify whether every participant had a reference result available at that time. No assumptions about missingness or analysis populations should be inferred from the completed status. Without the analysis definitions and participant-level flow, the extent to which the intended population and analyzed population align cannot be assessed.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| MRI of the Abdomen | 0 | 21 | 0.0% |
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 |
|---|---|
| MRI of the Abdomen | 0 of 21 |
For the MRI of the abdomen group, the registry lists 21 participants at risk for serious adverse events and 0 participants affected. It also lists 21 participants at risk for other adverse events and 0 participants affected. These are the posted event counts for this single group; they are not a comparison with a control arm.
The death count is not reported in the registry record. The record does not provide event descriptions, severity grading beyond the serious-versus-other grouping, timing, duration of safety monitoring, or information about how events were collected. It also does not describe whether any events were considered related to the MRI procedure.
In general, a zero count in a registry safety field means that no affected participants are listed for that field. It does not establish that an event was impossible, nor does it provide detailed information about ascertainment or completeness. The safety figures should therefore be read as recorded counts for the stated group, not as a standalone assessment of risk or as evidence comparing MRI with another procedure.
12. What the Result Does, and Does Not, Mean
The record establishes that a completed single-group study evaluated abdominal MRI for appendicitis in children aged 8–18. It describes MRI as the intervention and identifies sensitivity, specificity, positive predictive value, and negative predictive value as primary diagnostic measures. It also records that participants could receive ultrasound and CT, and that the diagnostic outcome was framed against surgical findings or clinical follow-up.
Those details do not establish the observed accuracy of MRI. Numerical diagnostic estimates, confidence intervals, classification counts, and comparative results are not reported in the registry record. The record therefore cannot show how precise any estimate was, how MRI compared with CT or ultrasound, or how often imaging classifications agreed with the stated reference. The completed status does not substitute for the missing results.
In general, a diagnostic study’s estimates apply to the participants evaluated and to the test procedures, reference definitions, and analysis methods used. They do not automatically establish performance in every clinical setting or population. Here, additional eligibility criteria, the reference-standard procedures, and the analysis population are not reported. The results needed to judge the relevance of the study beyond its registered description are also absent.
The single-group design is not a randomized comparison of assigned imaging approaches. The record’s statement that some participants underwent more than one imaging procedure describes test receipt; it does not itself show that an analysis compared those tests or that one was superior. The brief summary states a comparative aim, but no comparative findings are posted.
Accordingly, this record supports a description of the study question and design, not a conclusion about whether MRI did or did not perform well. It also does not establish clinical consequences, because those outcomes are not reported. The safety fields list no affected participants for serious or other adverse events, but the record does not provide enough detail to interpret event ascertainment or compare safety across procedures.
13. Why This Trial Matters Statistically
This study is statistically relevant because diagnostic performance is not captured by a single measure. Sensitivity, specificity, positive predictive value, and negative predictive value describe different parts of the relationship between an imaging result and a reference classification. A study that reports them with clear denominators and uncertainty can help readers understand both the kinds of classification errors and the precision of the estimates.
The record also illustrates why the reference standard must be explicit. The primary outcome description names surgical findings or clinical follow-up, while the brief summary frames MRI in comparison with CT and/or ultrasound performed at the same time. Those are related but distinct statistical questions. Clear definitions are needed to interpret estimates against a reference and to evaluate comparative performance between tests.
The single-group model is important to interpretation. Receiving MRI and, for some participants, other imaging procedures does not make this a randomized trial of imaging strategies. Design and analysis determine what comparisons can be supported. The record’s lack of posted analyses means that readers cannot assess how the stated diagnostic aims were translated into estimates, or how uncertainty and missing information were handled.
Finally, the registry distinguishes enrollment and test receipt from analyzed diagnostic data. It records enrollment of 21 and reports counts for receipt of other imaging, but does not give diagnostic denominators or result estimates. This gap matters because statistical interpretation depends on the actual information contributing to each measure, not only on the registered study design. The record is useful for identifying the question and methods intended, while its absence of numerical results limits what can be concluded.
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.
Several trial-specific details needed to interpret diagnostic performance are not reported in the registry record. These include eligibility criteria beyond the age range in the official title, the clinical setting, the MRI acquisition and reading procedures, the CT and ultrasound procedures, and whether image readers were masked to other test results or clinical information. Masking is recorded as single, but the masked party and implementation are not identified.
The reference standard is described as surgical findings or clinical follow-up, but the record does not explain how a participant was assigned to either source, how follow-up classifications were defined, or how discordant information was resolved. It also does not report the number with an available reference classification. Those details are central to interpreting sensitivity, specificity, and predictive values.
The brief summary presents a comparison with CT and/or ultrasound performed at the same time, while the primary outcome description names surgical findings or clinical follow-up as the comparison basis. No numerical estimates or analyses are posted to clarify how these aims were addressed. The record lists no analysis entries, and does not report missing-data methods, analysis populations, confidence intervals, or a multiplicity plan.
Enrollment is recorded as 21, but that does not establish the denominator available for every diagnostic measure. The record gives counts for participants receiving ultrasound and CT, yet does not provide complete paired results or explain whether any tests were uninterpretable. The registered planning assumptions describe a two-arm illustration, whereas the study model is single group; no trial-specific sample-size justification is reported. These limitations prevent assessment of the precision and robustness of any diagnostic findings from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Magnetic Resonance Imaging (MRI) of Appendicitis in Children — NCT00723788.
- Registry record last updated 2014-11-21; status last verified 2014-11.
- Results first posted 2014-11-21.
- 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
NCT00723788, titled “Magnetic Resonance Imaging (MRI) of Appendicitis in Children,” is listed as completed. Its official title identifies MRI evaluation in children aged 8–18. The record describes a single-group study with enrollment of 21 and MRI of the abdomen as the intervention. The study start is recorded as 2008-08, with primary completion in 2010-04.
The primary outcome names sensitivity, specificity, positive predictive value, and negative predictive value, using surgical findings or clinical follow-up as the reference basis. The brief summary also describes an aim to assess MRI against CT and/or ultrasound performed at the same time. All patients received MRI; 20 also received ultrasound and 9 CT, with 8 receiving all three procedures.
Numerical diagnostic results, analysis entries, confidence intervals, and detailed analysis methods are not reported in the registry record. The safety fields list 0 participants affected by serious adverse events and 0 affected by other adverse events among 21 at risk in the MRI group; the death count is not reported.