Evaluation of the Accuracy of the Elastic Fusion MRI-ultrasound Obtained in Vivo by the Koelis™ System

Study Overview
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Brief Summary
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The study aims at quantifying the registration error obtained in routine patients in different parts of the prostate and for operators with different experience in order to assess the average precision of the elastic MR-ultrasound fusion obtained by Koelis™ system. Patients referred for placement of intraprostatic fiducials before radiotherapy for prostate cancer will be prospectively offered to enter the study. The fiducials will be placed under transrectal ultrasound guidance, in the prostate apex, midgland and base, according to our routine procedure. A 3D Ultrasound acquisition of the prostate will be obtained at the end of the placement. As per our routine procedure, patients will undergo unenhanced prostate MRI to control the position of the fiducials. An elastic fusion of the MR images and the 3D ultrasound acquisitions will be retrospectively performed by operators of varying experience using the Koelis system. The fiducials (visible on MR and ultrasound images) will be used to quantify the registration error.

Official Title
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Evaluation of the Accuracy of the Elastic Fusion MRI-ultrasound ((Magnetic Resonance Imaging) Obtained in Vivo by the Koelis™ System

Conditions
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Cancer of the Prostate

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years Patient requiring placement of intraprostatic fiducials No contra-indication for fiducials placement No contra -indication to MRI No contra -indication for intravenous injection of gadolinium chelates Patient affiliated to the social security system Patients who received oral and written information Exclusion Criteria: Patient deprived of liberty as a result of a judicial or administrative decision. Patient under guardianship or curatorship. Any event preventing or prematurely interrupting the collection of assessment criteria would result in the premature exit of the subject.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Accuracy of the overall registration obtained by the Koelis™ system | The fusion will be performed retrospectively without interfering with patient management. This fusion is an off-line analysis that will be performed within one month of the images acquisition. Each of the four operators will perform a US/MR fusion for all patients and will be blinded to the fusions performed by the others. The results will be presented when all operators have finished the fusions in all patients. The overall registration error (TRE3D, defined as the Euclidean distance between the US marker and the MR marker after fusion) will be calculated based on the 3D coordinates of the fiducials on MR and ultrasound images. | 1 month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Influence on TRE3D of the position of the fiducials (apex, midgland and base) | The fusion will be performed retrospectively without interfering with patient management. This fusion is an off-line analysis that will be performed within one month of the images acquisition. Each of the four operators will perform a US/MR fusion for all patients and will be blinded to the fusions performed by the others. The results will be presented when all operators have finished the fusions in all patients. The distribution of TRE3D for the markers at the apex, midgalnd and base will be compared | 1 month | 
| Influence on TRE3D of the experience of the fusion operators | The fusion will be performed retrospectively without interfering with patient management. This fusion is an off-line analysis that will be performed within one month of the images acquisition. Each of the four operators will perform a US/MR fusion for all patients and will be blinded to the fusions performed by the others. The results will be presented when all operators have finished the fusions in all patients. The distribution of TRE3D for the four operators will be compared | 1 month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ultrasound, Koelis system, MRI, gold grain