From: Colorectal liver metastases: radiopathological correlation
Imaging feature | Histological features | Assessment of pathological response to chemotherapy | Limitations/pitfalls |
---|---|---|---|
Size modification | |||
Size increase | Viable tumor Acinar central necrosis | No response/progression | Pseudo-progression with immunomodulating agents |
Size decrease | Possible remnant viable tumor cell at the periphery Fibrosis deposition Infarct-like necrosis | Partial or major histological responsea | Poor correlation between size decrease and extent of pathological response |
Tumor enhancement | |||
Enhancement on delayed phase | Fibrosis deposition | The more fibrosis the better the response | Impossible to differentiate from pre-existing fibrous stroma on imaging Importance of comparing pre and post treatment exams |
Central enhancement on hepatobiliary phase | Fibrosis deposition | The more fibrosis the better the response | Impossible to differentiate from pre-existing fibrous stroma on imaging Importance of comparing pre and post treatment exams |
Margins | |||
Sharp liver-tumors interface, no enhancement | Absence or limited amount of remnant tumor cells | Major to complete responseb | Only described with CT |
Enhancing liver-tumor interfacec | Remnant tumor cells | Absent or minor responseb | The distinction between the two histologic findings is impossible on imaging Importance of comparing pre and post treatment exams |
Dangerous halo (highly proliferating infiltrative tumor cells at the tumor periphery) | Peripheral regrowth after initial response | ||
Tumor content | |||
Calcifications | Mineralization of necrotic tissue | Major response | Tumor regrowth is still possible |
Central non-enhancing areas, with high ADC value | Acinar central necrosis | Absent or minor response | The distinction between these histologic findings is impossible on imaging Importance of comparing pre and post treatment exams |
Infarct-like necrosis | Partial or major histological response | ||
Mucinous subtype | – | ||
Mucinous regression | Variable histological response |