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Rectal Gas Removal Through Small Catheter Placement Prior to MRI of the Prostate (GAS)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT03987737
Recruitment Status : Not yet recruiting
First Posted : June 17, 2019
Last Update Posted : June 17, 2019
Information provided by (Responsible Party):
Universitaire Ziekenhuizen Leuven

Brief Summary:
The presence of rectal gas can cause distortion at air-tissue interfaces on diffusion-weighted images (DWI) of prostate MRI and reduce image quality due to these susceptibility artifacts. Small catheter placement in the rectum before MRI is one of the ways that is advocated in PI-RADS v2 guidelines to reduce rectal gas. The goal of this study is to prospectively evaluate the effect of small catheter placement on artifacts on diffusion weighted images and to see whether it improves diagnostic accuracy.

Condition or disease Intervention/treatment Phase
Prostatic Neoplasms Prostate Cancer Procedure: small urinary catheter placement in the rectum Not Applicable

Detailed Description:

The value of MRI in the detection of clinically significant prostate cancer has already been shown in many studies [1]. With MRI widely available and general accepted by urologists and radiologist for prostate imaging, a good execution and high quality of the images have become crucial. Recently Caglic et al published an article about optimizing prostate mpMRI [2]. One of the factors that influences image quality is rectal loading and bowel movement. The prostate is located anterior in the immediate vicinity of the rectum, so prostatic MRI is prone to artifacts caused by bowel movements and to susceptibility artifacts at the air-tissue interface [3]. Rectal movements are correlated to the degree of rectal distension and result in significant displacement of the prostate gland [4]. Rectal distension has a negative impact on the quality of both T2-weighted (T2W) and diffusion weighted images (DWI) [5], which are the two most important sequences in the detection of clinically significant prostate cancer. A study by Lim et al [6] showed a significant correlation between the amount of stool in the rectum and the severity of motion artifacts, however reducing the amount of stool with an enema did not improve the quality of T2W, DWI or dynamic contrast enhanced (DCE) images compared to the non-enema group. As the authors have declared, this could be due to the fact that only a minority of patients in the non-enema group had moderate or large amounts of stool (15.6%).

This study by Lim et al also showed that the amount of rectal gas did not correlate with the severity of distortion artifacts on diffusion images, which could mean that even a small amount of gas could already cause substantial (susceptibility) artifacts on DWI. A larger study by Griethuysen et al [7] showed that a micro-enema shortly before the examination reduces both the incidence and the severity of gas-induced artifacts.

So, moving gas appears to be the main concern and preparation is recommended. There is no evidence that one rectal emptying strategy is better than another [8]. In PI-RADS v2, different approaches are suggested, the aforementioned micro-enema, performing the MRI exam with patient in the prone position or to decompress the rectum using a small catheter [9].

This study aims to assess the efficacy of small catheter placement just before the MRI examination in reducing susceptibility on diffusion weighted images.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 46 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: This is a prospective, single center, comparative study between two rectal emptying strategies. Patients will be randomized into one of two arms. In both arms the subjects will be asked to evacuate the rectum as much as possible prior to the MRI exam. In the study arm, a small catheter will be placed in the rectum by the MRI technician and the examination will be executed with the small catheter in situ. In the control arm, subjects will be scanned immediately after rectal evacuation on the toilet. If the DWI sequence is non-interpretable due to susceptibility artefacts, excessive air will be removed with small catheter placement eventually and the scan will be repeated.
Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: Rectal Gas Removal Through Small Catheter Placement Prior to MRI of the Prostate: Assessment of the Impact on Diffusion Weighted Images Artifacts and Diagnostic Accuracy
Estimated Study Start Date : August 2019
Estimated Primary Completion Date : October 2019
Estimated Study Completion Date : October 2020

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: small catheter
In the study arm, a small catheter will be placed in the rectum by the MRI technician and the examination will be executed with the small catheter in situ.
Procedure: small urinary catheter placement in the rectum
The MRI technician will place a small urinary catheter in the rectum prior to MRI of the prostate to evacuate excessive gasses. This catheter will stay in the rectum during the whole MRI examination.

No Intervention: control group
In the control arm, subjects will be scanned immediately after rectal evacuation on the toilet without small catheter in situ.

Primary Outcome Measures :
  1. degree of distortion of the prostate on AP direction on DWI compared to T2W images in mm [ Time Frame: 1 week ]
    The difference in diameter in anterio-posterior direction between axial DWI and the corresponding T2W images

Secondary Outcome Measures :
  1. Number of clinically significant cancers detected more due to improved quality of images [ Time Frame: within 1 year ]
    compared to control group, and with biopsy/pathological specimen as reference

  2. Number of rescans due to insufficient image quality after small catheter placement [ Time Frame: within 1 year ]
    compared to control group

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   45 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   Male
Gender Based Eligibility:   Yes
Gender Eligibility Description:   participants needs to have a prostate
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • willing to participate in the study by giving written informed consent.
  • male subjects aged between 45 to 80 years.
  • scheduled for a prostate MRI due to clinical suspicion of prostatic carcinoma (elevated prostate specific antigen (PSA) levels in blood and/or abnormal digital rectal examination (DRE)), staging, follow-up or active surveillance.
  • good health condition based on medical history, physical examination and vital sign measurements.

Exclusion Criteria:

  • has a contra-indication for MRI (claustrophobia, non-compatible metallic implants).
  • has a prior history of hip prosthesis.
  • has any condition, physical, mental, familial or sociological, that could impede compliance with the study protocol and further follow-up. This is not an absolute contra-indication, but should be discussed with patient prior to registration in the trial.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03987737

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Contact: Cindy Mai, MD 003216345032
Contact: Hilde Vandenhout 003216343636

Sponsors and Collaborators
Universitaire Ziekenhuizen Leuven
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Principal Investigator: Cindy Mai, MD University Hospital Leuven, Department of Radiology
Publications of Results:

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Responsible Party: Universitaire Ziekenhuizen Leuven Identifier: NCT03987737    
Other Study ID Numbers: s.-nr
First Posted: June 17, 2019    Key Record Dates
Last Update Posted: June 17, 2019
Last Verified: June 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Universitaire Ziekenhuizen Leuven:
Prostatic neoplasm
bp MRI of the prostate
small rectal catheter placement
Additional relevant MeSH terms:
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Prostatic Neoplasms
Genital Neoplasms, Male
Urogenital Neoplasms
Neoplasms by Site
Prostatic Diseases