Ranta was born in Germany. She moved to New Zealand in 2007, where she was initially a consultant neurologist and lead stroke physician at the MidCentral District Health Board. and full professor in 2021. As of 2024, she is head of the Department of Medicine at the University of Otago's Wellington campus. Ranta's research is focused on stroke care and the development of interventions to improve stroke care. There were also differences in care received by Māori and Pacific patients. She is on several editorial boards, including those of
Stroke and
Neurology. == Selected works ==