| Summary: | Purpose To evaluate the association between magnetic resonance imaging (MRI)-based texture
parameters and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in patients
with non-mucinous rectal cancer.
Materials and Methods Seventy-nine patients who had pathologically confirmed rectal nonmucinous
adenocarcinoma with or without KRAS-mutation and had undergone rectal MRI
were divided into a training (n = 46) and validation dataset (n = 33). A texture analysis was performed
on the axial T2-weighted images. The association was statistically analyzed using the
Mann-Whitney U test. To extract an optimal cut-off value for the prediction of KRAS mutation, a
receiver operating characteristic curve analysis was performed. The cut-off value was verified
using the validation dataset.
Results In the training dataset, skewness in the mutant group (n = 22) was significantly higher
than in the wild-type group (n = 24) (0.221 ± 0.283; -0.006 ± 0.178, respectively, p = 0.003). The
area under the curve of the skewness was 0.757 (95% confidence interval, 0.606 to 0.872) with
a maximum accuracy of 71%, a sensitivity of 64%, and a specificity of 78%. None of the other
texture parameters were associated with KRAS mutation (p > 0.05). When a cut-off value of
0.078 was applied to the validation dataset, this had an accuracy of 76%, a sensitivity of 86%,
and a specificity of 68%.
Conclusion Skewness was associated with KRAS mutation in patients with non-mucinous rectal
cancer.
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