Dr Amna Abdel-Gadir, Clinical Research Fellow1
- Dr James C Moon, Reader and Consultant Cardiologist1, 2
- Dr J Malcolm Walker, Consultant Cardiologist1, 2
- Professor John Porter, Professor of Haematology3
- Dr Martin Ugander, Consultant in Clinical Physiology4
- Dr Dr Alberto Roghi, Consultant Cardiologist5
- Heart Hospital, University College London Hospitals, London UK
- Hatter Cardiovascular Institute, University College Hospital London, UK
- Department of Haematology, University College London, UK
- Department of Clinical Physiology, Karolinska Institute, Stockholm, Sweden
- Department of Cardiology and Cardiac Surgery,Milan, Italy
Background to Research on T1 mapping of the heart
Iron overload has become a global health concern due to the number of patients world-wide requiring blood transfusion on a regular basis, such as in thalassaemia and sickle cell disease, adding to the numbers affected by inherited conditions such as haemochromatosis.
Cardiac iron deposition over time leads to heart failure and premature death. Chelation therapy removes iron but is expensive and needs monitoring of tissue iron levels to fully assess efficacy. Since a BHF funded project obtained by Prof. Dudley Pennell and Dr J Malcolm Walker in 2000, such monitoring has been possible non-invasively using MRI (T2* technique), and for the commonest conditions leading to iron overload, this measurement has become the accepted standard of care.
A new technique, T1 mapping, promises advantages of time and potential cost, compared to T2*. Our pilot work (n=88) shows that in one single breath-hold scan (taking half as long as the T2* sequence), an instant colour map is produced showing the iron content. The test was abnormal in 1 in 3 patients where the T2* value was normal (>20 ms) . T1 mapping was 5 times more reproducible than T2*.
We will explore T1 mapping as a potential complementary test to T2* for clinical care of patients at risk of cardiac iron load. We hypothesize that T1 detects iron overload earlier and more sensitively than T2*.
Figure Cardiac T1 mapping in health (a) and mild (b), moderate (c) and severe (d) iron overload, secondary to blood transfusion in beta thalassaemia major. Iron makes the heart go blue. The doughnut shaped object is a cross-section of the heart, where the change in colour (to blue) is seen under circumstances of increasing iron burden.