Abstract
Purpose: Assess whether application of a micro-enema can reduce gas-induced susceptibility artefacts in Single-shot Echo Planar Imaging (EPI) Diffusion-weighted imaging of the rectum at 1.5 T. Materials and methods: Retrospective analysis of n = 50 rectal cancer patients who each underwent multiple DWI-MRIs (1.5 T) from 2012 to 2016 as part of routine follow-up during a watch-and-wait approach after chemoradiotherapy. From March 2014 DWI-MRIs were routinely acquired after application of a preparatory micro-enema (Microlax (R); 5 ml; self-administered shortly before acquisition); before March 2014 no bowel preparation was given. In total, 335 scans were scored by an experienced reader for the presence/severity of gasartefacts (on b1000 DWI), ranging from 0 (no artefact) to 5 (severe artefact). A score >= 3 (moderate-severe) was considered a clinically relevant artefact. A random sample of 100 scans was re-assessed by a second independent reader to study inter-observer effects. Scores were compared between the scans performed without and with a preparatory micro-enema using univariable and multivariable logistic regression taking into account potential confounding factors (age/gender, acquisition parameters, MRI-hardware, rectoscopy prior to MRI). Results: Clinically relevant gas-artefacts were seen in 24.3% (no micro-enema) vs. 3.7% (micro-enema), odds ratios were 0.118 in univariable and 0.230 in multivariable regression (P = 0.0005 and 0.0291). Mean severity score (+/- SD) was 1.19 +/- 1.71 (no-enema) vs 0.32 +/- 0.77 (micro-enema), odds ratios were 0.321 (P < 0.0001) and 0.489 (P = 0.0461) in uni- and multivariable regression, respectively. Inter-observer agreement was excellent (kappa 0.85). Conclusion: Use of a preparatory micro-enema shortly before rectal EPI-DWI examinations performed at 1.5 T MRI significantly reduces both the incidence and severity of gas-induced artefacts, compared to examinations performed without bowel preparation.
Original language | English |
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Pages (from-to) | 131-137 |
Number of pages | 7 |
Journal | European Journal of Radiology |
Volume | 99 |
DOIs | |
Publication status | Published - 1 Feb 2018 |
Keywords
- Diffusion-weighted imaging
- Susceptibility artifacts
- Micro-enema
- Bowel preparation
- Rectal imaging
- Rectal cancer
- CANCER DETECTION
- CHEMORADIOTHERAPY
- DISTENSION
- PELVIS
- COIL