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The treatment of aortic aneurysms is today based on different indicators (diameters, lengths, angles, volumes of the arteries) measured on CT scan images. Several indicators are time consuming and complicatated to measure. They demand training and practice. Nurea is developing a software for automatic measurement of these indicators, PRAEVAorta® 2, to facilitate and assist the physician in his clinical routine.
The purpose of this study is to compare the analysis realised by the software PRAEVAorta® 2 with the analysis realised by the healthcare professional on retrospective CT scan images.
Contrasted and non-contrasted, pre-operation or post-operation CT scans from 50 patients will be analysed.
The main objectif is to validate the accuracy of the software by demonstrating its adequacy to the standard method of analysis.
The second objectives are the following:
We make the following assumption :
90% of the patients show 90% of adequacy to the healthcare professional analysis
Full description
The study PRAEVA-2-LP is realized in the University hospital of Leipzig. The treatment of aortic aneurysms is today based on different indicators (diameters, lengths, angles, volumes of the arteries) measured on CT scan images. Several indicators are time consuming and complicatated to measure. They demand training and practice. Nurea is developing a software for automatic measurement of these indicators, PRAEVAorta® 2, to facilitate and assist the physician in his clinical routine.
The purpose of this study is to compare the analysis realised by the software PRAEVAorta® 2 with the analysis realised by the healthcare professional on retrospective CT scan images.
Contrasted and non-contrasted, pre-operation or post-operation CT scans from 50 patients will be analysed.
We make the following assumption: 90% of the patients show 90% of adequacy to the healthcare professional analysis
This study is comparative, retrospective, non-interventional and monocentric. We compare the SaMD measurements to measurements realised using the standard method by a healthcare professional. The study analysis retrospective pseudonymised CT scans and deliver aggregated data. The study will be realised on a group of 50 subjects, which is small enough to have one site of investigation. Subjects will be their own witness. This strategy allows us to minimize the cost and the risks of the study without compromising the investigation. This investigation is submitted to the local ethics committee for approval according to paragraph 15 of Professional Code of the Saxon State Medical Association (Berufsordnung - BO) of 24 June 1998.
The study realised on the first version of the medical device PRAEVAorta® has shown a proportion of 93% of patient with measures calculated by the software in adequation with the measures realised following the standard method of analysis (ratio ≥ 90%). Because the new version of the software PRAEVAorta®2 has been improved, we expect to observe the same proportion.
Patient number calculation:
Hypotheses are the following:
H0: The proportion of patients with an absolute mean discrepancy > 5mm is 90% H1: The proportion of patient with an absolute mean discrepancy ≤ 5mm is strictly over 90% For this statistical analysis, variables are quantitative: aorta measurements. We consider over here the proportion of patients per sub-group who have as less or greater than 90%.
Comparison of two proportions: a theoretical proportion with an observed proportion The theoretical proportion ϕ0 is 90% The observed proportion ϕ is 93% (the observed proportion in the study of PRAEVAorta® 1) Therefore, the numbers of patients needed, with an α risk of 5% and a β risk of 0.9% is 32 in unilateral n=([1,96(φ0(1-φ0))^0,5 +u2β(φ(1-φ))^0,5]^2)/([φ0-φ]^2)=32 For security reasons and to anticipate any problem we choose to include approximately 10% more subjects. Moreover, to be sure that the amount of data is sufficient for CE marking we add another 15%. Therefore, the total of patient is 50.
The collected data comes from a database built by the hospital especially for retrospective study. The patient consent has already been collected at the creation of the database which exempt us from collecting it again.
The collected data are the gender, the birthdate of the patient, the scan manufacturer, the contrast-enhanced CT scan, the date of realization of the CT scan, the indicators, the healthcare professional trust in the results of the analysis realized by the software.
Images' analysis Pseudonymised images in DICOM format will be analysed. Pre-operation and post-operation thin-sliced CT images will be analysed.
Procedure to follow:
The comparison of data will be done during the statistical analysis.
The data will be collected in an EDC / e-CRF. The software allow authentication, account management with several level of access to the different parts and data. Exchanges are secured and data are stored on a Health Data Host accredited server. A back-up is regularly made.
The practician fills a form / report when measuring the indicators and the software PRAEVAorta® 2 is returning a pdf report. The data collected in the EDC will be compared with the data present in those two reports and in the hospital study database.
Most monitoring will be realised in remote. A monitoring visit will be realised at mid-time. A data review and validation will be realised before database lockdown. Data will then be validated by the PI and the data manager.
Data management:
Data collected are pseudonymised to ensure confidentiality and medical secret and registered in the e-CRF.
Demographic data as well as scans are available in the hospital's database, set up specifically for retrospective data studies. Measures realised on the CT scans are registered on an electronic report, for both measurements methods. The data from those reports and from the database are reported in the e-CRF. Analysed CT scans are also uploaded in the e-CRF.
Data cannot be registered in the software before the subject's inclusion has been validated.
Data entered into the software must be double-checked to limit errors.
Data validation:
This requirement is achieved through Source Data Verification, the process by which the information reported on the e-CRF by the investigator is compared with the original medical records to ensure it is complete and accurate during monitoring visits and closure visit.
In addition, a system of dynamic consistency checks is implemented in the e-CRF for rapid data validation when applicable.
Through the Source Data Validation process, the monitor should confirm accurate transcription of data from source files to the CRF and that the CRF contains all the relevant information about the patient's participation in the clinical trial.
Monitoring visit process
Process:
The first monitoring visit will be conducted after the completion of the Step 4. of the procedure has been completed, to review first part of data. The rest will be reviewed in close-out visit.
Monitoring call and conference will be realized at the end of each step and when required The Monitoring visit will review all of the responsibilities listed above. Following each monitoring visit / call, a monitoring report will be submitted to the QI.
The following activities may take place during each monitoring visit:
The following participant data will be source data verified for the indicated percentage of participants enrolled in the trial and all incidences reported since the last monitoring visit:
100% of eligibility criteria 100% of participant CRFs
Any updates and/or revisions to the following study documents since the last monitoring visit will also be reviewed:
Training documentation/records and Task Delegation Log updates Regulatory documentation including Health Canada approval/amendments
The following activities may be conducted at each monitoring visit:
Trial Master File
Investigator and Site Personnel Responsibilities
CRF Review / Source Documentation Verification. Verify the following:
Device Deficiency (DD)
Protocol Deviations
General
Visit Conclusion
At the conclusion of the visit, the monitor will meet with the QI and site research staff to review visit findings and answer questions. The monitor will discuss the following topics at a minimum:
Statistics:
Aggregated data analysed as treated and per subgroup. Descriptive analysis
Inferential analysis Objective: comparing an observed proportion p1 with a theoretical proportion p0 p1: proportion of adequate data p0: theoretical proportion: 90%
A one-sided right test will be realised to evaluate the comparison
Evaluation criteria:
Principal criteria:
Secondary criteria:
Evaluation of the measurements and the segmentations:
Evaluation of risks:
Enrollment
Sex
Ages
Volunteers
Inclusion criteria
Exclusion criteria
Patients with
50 participants in 1 patient group
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Central trial contact
Lamia STEPHAN; Florian BERNARD
Data sourced from clinicaltrials.gov
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