[Value of diffusion-weighted MRI in the diagnosis of T staging for rectal cancer]

To investigate the value of diffusion-weighted imaging (DWI) in the diagnosis of T staging for rectal cancer.

Clinicopathologic data and MR images of 46 patients with rectal cancer in our hospital from July 2013 to September 2014 were retrospectively analyzed. The diagnostic sensitivity, specificity and accuracy of T2WI were compared with those of T2WI plus DWI in T staging for rectal cancer. The relationship of mean apparent diffusion coefficient (ADC) value with different T stages of rectal cancer was analyzed.

There were no significant differences in the diagnostic sensitivity, specificity and accuracy between T2WI and T2WI plus DWI (all P>0.05). The mean ADC value of DWI performed in pathologic T2, T3a, T3b, T3c and T4 stage was (1.110 ± 0.117) × 10⁻³ mm²/s, (1.035 ± 0.121) × 10⁻³ mm²/s, (0.948 ± 0.109) × 10⁻³ mm²/s, (0.932 ± 0.122) × 10⁻³ mm²/s and (0.843 ± 0.050) × 10⁻³ mm²/s, respectively (F=6.972, P=0.000).

DWI can serve as a complement for T2WI in the diagnosis of T stage patients with rectal cancer, and its ADC value presents a downward trend with the advance of T stage.