His research interests lie in CMR, specifically in the assessment and differentiation of cardiomyopathies, the measurement of myocardial iron and the assessment of chelation treatment, the detection and assessment of early atherosclerosis, and myocardial perfusion imaging. He regularly lectures at key international cardiology events and has published >350 papers on his specialist subjects. These include CMR of cardiomyopathy and the early diagnosis of myocardial iron overload (Eur Heart J 2001; 22: 2171-9) to wide acclaim. Professor Pennell's involvement in teaching includes postgraduate training in CMR; Junior doctors training meetings and international training meetings. He has supervised over 25 research students, who have won many awards over the years including most recently the NHLI Best Thesis Prize in 2008 & 2012.