The Influence of Bowel Preparation on ADC Measurements: Comparison between Conventional DWI and DWIBS Sequences.

The aim of the study was to assess whether there were differences between apparent diffusion coefficient (ADC) values of diffusion-weighted imaging (DWI) and diffusion-weighted imaging with background body signal suppression (DWIBS) sequences in non-prepared and prepared bowels before and after preparation with an enteric hyperosmolar agent, to assess whether ADC measurements have the potential to avoid bowel preparation and whether ADC-DWIBS has advantages over ADC-DWI. 106 adult patients without evidence of inflammatory bowel disease (IBD) underwent magnetic resonance (MR) enterography before and after bowel preparation. ADC-DWI and ADC-DWIBS values were measured in the intestinal and colonic walls demonstrating high signal intensity (SI) at DWI tracking images of b = 800 s/mm before and after preparation. There were significant difference ( < 0.0001) in both ADC-DWI and ADC-DWIBS results between non-prepared and prepared jejunum for DWI being 1.09 × 10 mm/s and 1.76 × 10 mm/s, respectively, and for DWIBS being 0.91 × 10 mm/s and 1.75 × 10 mm/s, respectively. Both ADC-DWI and DWIBS also showed significant difference between non-prepared and prepared colon ( < 0.0001), with DWI values 1.41 × 10 mm/s and 2.13 × 10 mm/s, and DWIBS-1.01 × 10 mm/s and 2.04 × 10 mm/s, respectively. No significant difference between ADC-DWI and ADC-DWIBS was found in prepared jejunum ( = 0.84) and prepared colon ( = 0.58), whereas a significant difference was found in non-prepared jejunum and non-prepared colon ( = 0.0001 in both samples). ADC between DWI and DWIBS does not differ in prepared bowel walls but demonstrates a difference in non-prepared bowel. ADC in non-prepared bowel is lower than in prepared bowel and possible overlap with the ADC range of IBD is possible in non-prepared bowel. ADC-DWIBS has no advantage over ADC-DWI in regard to IBD assessment.