Predicting histopathological growth patterns and prognosis of colorectal liver metastases using MRI

To identify MR imaging features of replacement histopathological growth patterns (rHGPs) of colorectal liver metastases (CRLMs) distinguishable from those of desmoplastic HGPs (dHGPs) and explore their relationships with prognosis.

Seventy-nine patients with 104 CRLMs who underwent gadoxetic acid-enhanced MR followed by partial hepatectomy were included as a derivation cohort. The CRLMs were rHGPs or dHGPs. MR images of the CRLMs, focusing on the tumor and segmented tumor-liver interface zones (peritumoral area), were quantitatively evaluated and statistically analyzed. The statistically significant findings from the derivation cohort were validated in an independent external cohort.

In the derivation cohort, there were no significant differences among tumor sizes, contrast-to-noise ratios (CNRs), or enhancement ratios (ERs) of the tumors with rHGPs (n = 43) and dHGPs (n = 61) (p > 0.05). The peritumoral area was only identified during the arterial and portal phases. The thickness, CNR, and ER of the peritumoral area on the arterial and portal phase images of the rHGP group were significantly larger than those of the dHGP group (p < 0.05). The area under the ROC curve for predicting rHGP based on CNR during the arterial phase was the highest at 0.920. The peritumoral area CNR during the arterial phase was associated with a poor prognosis (p < 0.05). The usefulness of these parameters was confirmed in the validation cohort (p < 0.05).

The CRLMs with rHGPs had thicker peritumoral areas with higher CNR and ER during the arterial phase, and the CNR during the arterial phase was an independent indicator of poor prognosis.

Question Can MR imaging characteristics predict histopathological growth patterns (HGPs) of colorectal liver metastases (CRLMs), which have been established as independent predictors of prognosis? Findings CRLMs with replacement HGPs showed thicker, more enhanced peritumoral areas with higher contrast ratios than those with desmoplastic HGPs during the arterial phase. Clinical relevance Increased thickness and predominant enhancement of the peritumoral area during the arterial phase may serve as predictive markers for identifying replacement HGPs in CRLMs, which are linked to a poorer prognosis, in contrast to desmoplastic HGPs.