Dr Rennie studied medicine at St Bartholmews and The Royal London Medical College. His general radiological training was at the Oxford Radcliffe NHS Trust, before completing his fellowship in neuroradiology at the Radcliffe Infirmary.
He was appointed consultant neuroradiologist at University Hospital Coventry and Warwickshire NHS Trust in 2007, before taking up his current appointment as consultant interventional neuroradiologist at The National Hospital for Neurology and Neurosurgery in 2011. He holds an honorary contract at Great Ormond Street Hospital for Children.
In addition to diagnostic neuroradiology reporting, he performs neurointerventions across the entire range of adult and paediatric practice. Along with the team at Great Ormond Street Hospital he provides the Nationally Commissioned service of Vein of Galen Malformation.
He is a nationally and internationally recognized paediatric interventional neuroradiologist.