Objective:

To compare dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in evaluating microvascular content in rectal cancer.

Methods:

This study was conducted on 23 patients with rectal adenocarcinoma confirmed by preoperative endoscopic pathology in Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from December 2019 to December 2022. All subjects underwent IVIM-DWI and DCE-MRI scans before surgery. The DCE-MRI parameters calculated by the Tofts model were extracellular space volume fraction (V

e

)

space transport coefficient (K

trans

)

and rate constant of extracellular space return to intravascular space (K

ep

). The IVIM-DWI parameters were calculated by the double exponential model: simple diffusion coefficient (

D

)

perfusion related diffusion coefficient (

D

*)

and perfusion fraction (

f

). The correlation between DCE-MRI and IVIM-DWI quantitative parameters and microvascular content in rectal cancer was analyzed and compared.

Results:

There were significant differences in K

trans

and

D

values of colorectal cancer in different pathological grades (

F

=9.159

P

=0.002;

F

=5.106

P

=0.016). K

trans

was superior to the

D

value in evaluating rectal cancer grading. K

trans

K

ep

and

D

* were positively correlated with microvascular content in rectal cancer (

r

=0.734

P

=0.000;

r

=0.617

P

=0.002;

r

=0.456

P

=0.029). DCE-MRI quantitative parameters were superiorto IVIM-DWI quantitative parameters in evaluating microvascular content in rectal cancer.

Conclusion:

DCE-MRI was superior to IVIM-DWI in evaluating the differentiation degree and microcycle status of

rectal cancer. However

considering that IVIM-DWI does not require injection of contrast agents

IVIM-DWI can still be recommended for the microcirculation of rectal cancer.