Table 3.

Ocular melanoma metastasis imaging

Key points to remember
Liver is the most common site of metastasis and prognosis is based on the surveillance and treatment of liver metastasis
MRI
The most specific modality for imaging liver metastasis and is at least as sensitive as CT
Majority of melanoma metastases are not T1 bright. T1 hypointense lesions are aggressive and grow rapidly
Newer hepatobiliary contrast agents help in detection of very small liver metastases
Diffusion-weighted imaging is helpful when i.v. contrast cannot be administered
Treated lesions are also better evaluated with MRI. Decrease in size is not a criterion for response to treatment. Perilesional enhancement does not indicate progression in treated lesions, rather nodular enhancement does
CT
Useful for lung metastasis and when MRI is medically contraindicated
Locoregional treated lesions can be also assessed with CT
Lesions treated with chemoembolization are assessed by presence of iodized oil in the treated segment. Washout out of the dense material suggests viable tumour
Ultrasound is mainly useful for biopsy of liver lesions
PET-CT
Detects lung nodules and large liver lesions but is insensitive to small liver lesions
High radiation dose is a major disadvantage

PET, positron emission tomography.