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Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: impact on colorectal polyp
Aoife N Keeling1, Martina M Morrin, Charles McKenzie
1Department of Radiology, Beaumont Hospital, Beaumont Road, Dublin 9, Ireland. aoifekeeling@hotmail.com
Purpose:
To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC).
Materials And Methods:
IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC.
Results:
Twenty-four polyps were detected in eighteen patients with CC (5 polyps ≥ 10 mm, 4 polyps 6-9 mm, 15 polyps ≤ 5 mm). MRC was 66.7% (12/18) sensitive and 96.4% (27/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5/5) and 100% (19/19), respectively, for lesions greater than 10mm, 100% (4/4) and 100% (20/20) for lesions 6-9 mm, and sensitivity of 20% (3/15) lesions less than 5mm. The sensitivity and specificity of MRC for detecting significant lesions (>6mm) was 100% (9/9) and 100% (15/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n=16) of patients preferred MRC as a future screening test compared to 33% (n=15) for CC.
Conclusion:
MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps ≥ 6 mm in size. Further studies are warranted.
Insights
MR colonography (MRC) with air contrast is a feasible and well-tolerated method for detecting colonic polyps 6 mm and larger. This technique shows high specificity and good sensitivity for significant lesions, offering a viable alternative to conventional colonoscopy.
Area of Science:
- Medical Imaging
- Gastroenterology
- Diagnostic Accuracy
Background:
- Conventional colonoscopy (CC) is the standard for colorectal polyp detection.
- Alternative imaging techniques are sought to improve patient experience and diagnostic yield.
Purpose of the Study:
- To compare the diagnostic accuracy and patient tolerance of MR colonography (MRC) using intravenous contrast and luminal air against conventional colonoscopy (CC).
- To evaluate MRC's effectiveness in detecting colonic polyps of various sizes.
Main Methods:
- Forty-six patients underwent MR colonography (MRC) with gadopenetate dimeglumine and parallel imaging, followed by conventional colonoscopy (CC).
- Diagnostic accuracy (sensitivity and specificity) and patient tolerance were compared between the two methods.
- Analysis included polyp detection rates based on size.
Main Results:
- MRC demonstrated 100% sensitivity and specificity for polyps ≥ 6 mm.
- Overall per-patient sensitivity was 66.7% and specificity was 96.4%.
- Patient tolerance was similar for both MRC and CC, with a slight preference for MRC in future screenings.
Conclusions:
- MR colonography (MRC) with air contrast is a feasible and well-tolerated technique for detecting colonic polyps ≥ 6 mm.
- MRC shows high diagnostic performance for significant colonic lesions.
- Further research is recommended to explore the full potential of MRC.
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