Local staging and assessment of colon cancer with 1.5-T magnetic resonance imaging

Abstract

Objective:: The aim of this study was to assess the accuracy of 1.5-T MRI in the pre-operative local T and N staging of colon cancer and identification of extramural vascular invasion (EMVI).

Methods:: Between 2010 and 2012, 60 patients with adenocarcinoma of the colon were prospectively recruited at 2 centres. 55 patients were included for final analysis. Patients received pre-operative 1.5-T MRI with high-resolution T₂ weighted, gadolinium-enhanced T₁ weighted and diffusion-weighted images. These were blindly assessed by two expert radiologists. Accuracy of the T-stage, N-stage and EMVI assessment was evaluated using post-operative histology as the gold standard.

Results:: Results are reported for two readers. Identification of T3 disease demonstrated an accuracy of 71% and 51%, sensitivity of 74% and 42% and specificity of 74% and 83%. Identification of N1 disease demonstrated an accuracy of 57% for both readers, sensitivity of 26% and 35% and specificity of 81% and 74%. Identification of EMVI demonstrated an accuracy of 74% and 69%, sensitivity 63% and 26% and specificity 80% and 91%.

Conclusion:: 1.5-T MRI achieved a moderate accuracy in the local evaluation of colon cancer, but cannot be recommended to replace CT on the basis of this study.

Advances in knowledge:: This study confirms that MRI is a viable alternative to CT for the local assessment of colon cancer, but this study does not reproduce the very high accuracy reported in the only other study to assess the accuracy of MRI in colon cancer staging.

Figure 1.

A sagittal T₂ weighted turbo spin-echo image showing a T2 sigmoid tumour confirmed on histopathology (arrow), correctly reported by one reader but overstaged as T3 by the second reader.

Figure 2.

An axial T₂ weighted turbo spin-echo image showing a T3c sigmoid tumour confirmed on histopathology (arrow), correctly reported by both readers.

Figure 3.

An axial T₂ weighted half-Fourier acquisition single-shot turbo spin-echo image showing a T4 transverse colon tumour confirmed on histopathology (arrow), correctly reported by both readers.

Figure 4.

An axial T₂ weighted turbo spin-echo image showing an involved lymph node confirmed on histopathology (arrow), correctly reported by both readers.

Figure 5.

A sagittal T₂ weighted turbo spin-echo image showing extramural vascular invasion confirmed on histopathology (arrow), correctly reported by one reader but not by the second reader.