Imaging characteristics of colorectal liver metastases on dynamic computed tomography
Abstract
Background: Colorectal cancer is a common cancer that has a high morbidity and mortality rate, and the liver is the most frequent metastatic organ. Dynamic computed tomography (CT) can be used to diagnose colorectal liver metastases based on their imaging characteristics and enhancing patterns which are different from other liver lesions.
Objective: To describe the imaging characteristics of colorectal liver metastases on dynamic CT. Methods: A cross–sectional study was conducted on 39 colorectal cancer patients with pathologically proven liver metastases. All patients underwent triphasic CT. Other lesions sharing similar imaging characteristics were considered metastases. Patient demographic and CT findings were documented
Results: 39 patients and 92 lesions were included in the analysis. Liver metastases can be solitary (48.7%) or multiple (51.3%). Most of them are located in the right lobe (62%) more than the left lobe. Lesions less than 5 cm have the highest rate (80.5%). Liver metastases are often well–defined (54.4%) with non-lobulated borders (58.7%). Calcification is rare (5.4%). Compared to the surrounding liver parenchyma, colorectal liver metastases have a lower density in the pre-contrast phase (89.3%), and are also less enhanced in arterial and venous phases (93.5% and 98.9% gradually). Contrast-enhanced lesions are usually heterogeneously (91.3%). Rim enhancement at the peripheral area is often observed (78.2%). Of 51 lesions, it appears on both arterial and venous phases (55.4%). Central necrosis is about 41.3% of the total lesions and dominantly appears in lesions larger than 3 cm.
Conclusions: Imaging characteristics of the colorectal liver metastases mostly observed are the thin rim enhancement at the peripheral area, low density in the pre-contrast phase, less enhancement than the normal surrounding liver parenchyma on both arterial and venous phases, central necrosis in the large lesions, and heterogeneously enhanced pattern
