Colorectal carcinoma: Ex vivo evaluation using q-space imaging; Correlation with histopathologic findings

Although the prognosis of colorectal carcinoma (CRC) patients depends on the histologic grade (HG) and lymph node metastasis (LNM), accurate preoperative assessment of these prognostic factors is often difficult.

To assess the HG and extent of LNM by q-space imaging (QSI) for preoperative diagnosis of CRC.

Prospective.

A total of 20 colorectal tissue samples containing adenocarcinomas and resected lymph nodes (LNs).

QSI was performed with a 3T MRI system using a diffusion-weighted echo-planar imaging sequence: repetition time, 10,000 msec; echo time, 216 or 210 msec; field of view, 113 × 73.45 mm; matrix, 120 × 78; section thickness, 4 mm; and 11 b values ranging from 0 to 9000 s/mm² .

The mean displacement (MDP; μm), zero-displacement probability (ZDP; arbitrary unit [a.u.]), kurtosis (K; a.u.), and apparent diffusion coefficient (ADC) were analyzed by two observers and compared with histopathologic findings.

Spearman's rank correlation coefficient, Mann-Whitney U-test, and ROC curve analyses.

For all 20 carcinomas, the MDP, ZDP, K, and ADC were 8.87 ± 0.37 μm, 82.0 ± 6.2 a.u., 74.3 ± 3.0 a.u., and 0.219 ± 0.040 × 10^-3 mm² /s, respectively. The MDP (r = -0.768; P < 0.001), ZDP (r = 0.768; P < 0.001), and K (r = 0.785; P < 0.001) were significantly correlated with the HG of CRC, but not the ADC (r = 0.088; P = 0.712). There were also significant differences in the MDP, ZDP, and K between metastatic and nonmetastatic LNs (all, P < 0.001), but not the ADC (P = 0.082). In the HG of CRC and LNM, the area under the curve was significantly greater for MDP, ZDP, and K than for ADC.

QSI provides useful diagnostic information to assess the HG and extent of LNM in CRC.

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1059-1068.