Eligibility and inclusion of patients .Total of 129 patients with melanoma brain metastases who received immunotherapy were screened for this retrospective study. Patients were excluded for no observed progression while receiving immunotherapy (n=73), non-measurable progression on DCE-MRI perfusion (n=10). Out of 67 lesions from 46 patients who were eligible, 3 lesions were excluded from this study as they were felt to be pseudoprogression, however, there was no histopathological confirmation nor sufficient follow up duration of 2 months. Finally, 64 lesions from 44 patients were included in the study, which comprised of 8 pseudoprogression lesions from 9 patients, and 55 progression lesions from 36 patients.