Objective:

To investigate the diagnostic value of conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) for patients with local recurrence after radical operation for rectal cancer.

Methods:

A total of 74 patients with rectal cancer recurrence were diagnosed by conventional MRI a

nd DWI. The pathological diagnosis results were used as the standard

and the receiver operating characteristic (ROC) curve analysis was used to compare the diagnostic efficiency of MRI and DWI.

Results:

Compared with normal muscle tissue

the MRI findings of patients with local recurrence after radical resection of rectal cancer showed that the tumor tissue showed low and equal signals on T1-weighted imaging (T1WI)

mixed high signals on T2-weighted imaging (T2WI)

and bright signals on DWI

and their apparent diffusion coefficient (ADC) values decreased significantlyand showed uneven or circular strengthening. Taking the pathological diagnosis as the standard

the sensitivity

specificity

positive predictive value

negative predictive value

Youden index

misdiagnosis rate and missed diagnosis rate of conventional MRI in diagnosis of patients with rectal cancer recurrence were 88.5%

86.4%

93.9%

76.0%

0.777

13.6% and 11.5%

respectively; DWI were 98.1%

95.5%

98.1%

95.5%

0.938

4.5% and 1.9%

respectively. ROC curve analysis showed that the area under curve (AUC) of MRI in diagnosis of patients with local recurrence after radical operation of rectal cancer was 0.874

AUC of DWI was 0.968

and AUC of DWI was higher than conventional MRI.

Conclusion:

Compared with conventional MRI

DWI is more valuable in the diagnosis of local recurrence of patients with rectal cancer after radical resection. It is worthy of clinical application.