Accuracy of multislice liver CT and MRI for preoperative assessment of colorectal liver metastases after neoadjuvant chemotherapy.

INTRODUCTION

To determine the best imaging modality for preoperative detection, characterization and measurement of colorectal liver metastases (CRLM) after neoadjuvant chemotherapy (NAC).

METHODS

A total of 79 lesions in 15 patients with CRLM were included. Following NAC, all patients received multislice liver CT (MSCT) and magnetic resonance imaging (MRI) that were scored by two observers for lesion number, type, diameter (mm) and segmental location. Intraoperative findings, histopathology and follow-up imaging were used as reference standard for surgically treated patients; non-surgical candidates underwent follow-up imaging.

RESULTS

Lesion detection rate was similar for MSCT and MRI (76 and 80%, respectively, p = 0.648). Lesion characterization was significantly superior (p = 0.021) at MRI (89%, κ 0.747, p = 0.001) compared to MSCT (77%, κ 0.235, p = 0.005). Interobserver variability for diameter measurement was not significant at MRI (p = 0.909 [95% CI -1.245 to 1.395]), but significant at MSCT (p = 0.028 [95% CI -3.349 to -2.007]). Differences in diameter measurement were independent of observer (p = 0.131), and no statistical effect from imaging modality on diameter measurement was observed (p = 0.095).

CONCLUSION

MRI is superior to MSCT in preoperative characterization and measurement of CRLM after NAC. Lesion detection rates for both modalities are comparable.