Evaluating the effect of rectal distension on prostate multiparametric MRI image quality

Iztok Caglic; Nienke L Hansen; Rhys A Slough; Andrew J Patterson; Tristan Barrett

doi:10.1016/j.ejrad.2017.02.029

Evaluating the effect of rectal distension on prostate multiparametric MRI image quality

Eur J Radiol. 2017 May:90:174-180. doi: 10.1016/j.ejrad.2017.02.029. Epub 2017 Feb 22.

Authors

Iztok Caglic¹, Nienke L Hansen², Rhys A Slough³, Andrew J Patterson³, Tristan Barrett⁴

Affiliations

¹ Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK. Electronic address: iztokcaglic@gmail.com.
² Department of Diagnostic and Interventional Radiology, University Hospital Cologne, Cologne, Germany; CamPARI Clinic, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK.
³ Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK.
⁴ Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK; CamPARI Clinic, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK.

PMID: 28583630
DOI: 10.1016/j.ejrad.2017.02.029

Abstract

Purpose: To evaluate the effect of rectal distension on the quality of anatomical and functional prostate multiparametric (mp) MRI.

Materials and methods: Multiparametric (mp) 3T-MRI images of 173 patients were independently evaluated by two radiologists in this retrospective study. Planimetry rectal volumes were derived and a subjective assessment of rectal distension was made using a 5-point Likert scale (1=no stool/gas, 5=large amount of stool/gas). Image quality of diffusion-weighted imaging (DWI) was evaluated using a 5-point Likert scale. DWI was further scored for distortion and artefact. T2W images were evaluated for image sharpness and the presence of motion artefact. The stability of the dynamic contrast-enhancement acquisition was assessed by recording the number of corrupt data points during the wash-out phase.

Results: There was a strong correlation between subjective scoring of rectal loading and objectively measured rectal volume (r=0.82), p<0.001. A significant correlation was shown between increased rectal distension and both reduced DW image quality (r=-0.628, p<0.001), and increased DW image distortion (r=0.814, p<0.001). There was also a significant trend for rectal distension to increase artefact at DWI (r=0.154, p=0.042). Increased rectal distension led to increased motion artefact on T2 (p=0.0096), but did not have a significant effect on T2-sharpness (p=0.0638). There was no relationship between rectal distension and DCE image quality (p=0.693). 63 patients underwent lesion-targeted biopsy post MRI, there was a trend to higher positive predictive values in patients with minor rectal distension (34/38, 89.5%) compared to those with moderate/marked distension (18/25, 72%), p=0.09.

Conclusion: Rectal distension has a significant negative effect on the quality of both T2W and DW images. Consideration should therefore be given to bowel preparation prior to prostate mpMRI to optimise image quality.

Keywords: Image quality; Multiparametric MRI; Prostate; Rectal distension; Susceptibility artefact.

MeSH terms

Aged
Artifacts
Diffusion Magnetic Resonance Imaging / methods*
Humans
Male
Middle Aged
Motion
Organ Size
Prostate / diagnostic imaging*
Prostate / pathology*
Retrospective Studies