Gastrointestinal tract, Abdomen, MR, MR-Diffusion/Perfusion, Diagnostic procedure, Fistula, Abscess
L. A. M. S. Mohsen, N. Osman; Minia/EG
We concluded that DWI alone was not superior to T2W regarding the visibility of perianal fistulas and abscesses.
Although T2W evaluation detected higher number of fistulas,
yet this didn’t reach significant level.
The best performance was for combined DWI and T2W evaluation,
although it wasn’t significantly higher than either sequence alone.
We believe that DWI is better used as part of the entire MRI study,
it should not replace T2W sequence.
We were able to confirm that DWI may be used as an alternative for post-contrast images,
especially in conjunction with T2W.
Using both sequences,
97.8 % were accurately seen and classified,
with no significant difference from the routine T2W and post-contrast evaluation of these patients.
And this applies to both inflammatory activity groups.
in our study,
only 1 case was misclassified (2.2 % of cases),
this case belonged to the NIA group of patients,
who are unlikely to have surgeries,
and thus no change of their proposed management.
We do still need a larger scale study to confirm the percentage of error when using combined DWI and T2W evaluation to classify perianal abscess and fistulas.
The first limitation,
in our study,
is the low number of cases.
The second limitation is that some patients with perianal fistulas refused surgery,
despite being indicated.
This may have affected their classification into PIA and NIA groups and accordingly may have altered the results.
We tried to reduce this bias by excluding patients with pre-operative diagnosis of perianal abscesses,
who refused the surgery.
our results may vary from other authors,
who used higher b values for the DWI sequence (1000 s/mm2) or used a large ROI for the recording the ADC value.