Rectal Gas Removal Through Small Catheter Placement Prior to MRI of the Prostate (GAS)
|ClinicalTrials.gov Identifier: NCT03987737|
Recruitment Status : Not yet recruiting
First Posted : June 17, 2019
Last Update Posted : June 17, 2019
|Condition or disease||Intervention/treatment||Phase|
|Prostatic Neoplasms Prostate Cancer||Procedure: small urinary catheter placement in the rectum||Not Applicable|
The value of MRI in the detection of clinically significant prostate cancer has already been shown in many studies . 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 . 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 . Rectal movements are correlated to the degree of rectal distension and result in significant displacement of the prostate gland . Rectal distension has a negative impact on the quality of both T2-weighted (T2W) and diffusion weighted images (DWI) , which are the two most important sequences in the detection of clinically significant prostate cancer. A study by Lim et al  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  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 . 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 .
This study aims to assess the efficacy of small catheter placement just before the MRI examination in reducing susceptibility on diffusion weighted images.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||46 participants|
|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)|
|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|
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.
- 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
- 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
- Number of rescans due to insufficient image quality after small catheter placement [ Time Frame: within 1 year ]compared to control group
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03987737
|Contact: Cindy Mai, MDfirstname.lastname@example.org|
|Contact: Hilde Vandenhoutemail@example.com|
|Principal Investigator:||Cindy Mai, MD||University Hospital Leuven, Department of Radiology|