A multisequential approach to cardiovascular magnetic resonance scans that highlight different aspects of heart structure and function may offer a better and safer way to identify potentially deadly inflammation of the heart muscle, according to a new study (PDF) in the June 7, 2005, issue of the Journal of the American College of Cardiology.
“In our opinion, a comprehensive approach increases the ability of cardiovascular magnetic resonance scanning to detect myocarditis. The method also offers the possibility of differentiating reversible and irreversible myocardial injury,” said Jeanette Schulz-Menger, M.D., at the Franz-Volhard-Klinik, Charité Campus Buch, Universität Medizin Berlin in Germany.
Acute myocarditis is a sudden, and potentially life-threatening, inflammation of the heart muscle that can be caused by an infection, toxins, autoimmune disorders or other causes. It can be difficult to diagnose because the early symptoms may look like a case of flu, heart failure or other ailments. The conventional diagnostic approach involves taking a biopsy of heart tissue for examination, but even this invasive technique is not foolproof. Because of the patchy nature of many cases, some areas of the heart are severely damaged, while others areas are not affected.
A reliable imaging technique could help identify patients with acute myocarditis more quickly and spare them from an invasive biopsy procedure. The researchers, including lead author Hassan Abdel-Aty, M.D., used a combination of different magnetic resonance imaging (MRI) techniques on 25 patients with suspected acute myocarditis (18 men and seven women) and 23 healthy controls (13 men and 10 women).
The so-called T1 and T2 magnetic resonance techniques are somewhat like taking photographs through a polarizing filter, aligned vertically for one image and then horizontally for the other. The researchers also captured images after injecting a contrast agent called gadolinium-DTPA.
They found that the combination of techniques produced better results than any single method.
“The best diagnostic performance was obtained when any two of the three sequences were positive in the same patient,” the researchers wrote.
“Our recommendation for clinicians is that in patients with suspected acute myocarditis apply cardiovascular magnetic resonance when it is available in a center with experience. However, there is still a need for multicenter prospective trials,” Dr. Schulz-Menger said.
In an editorial (PDF) in the journal, Peter P. Liu, M.D., F.A.C.C., at the University of Toronto in Ontario, Canada, and his co-authors noted that this trial compared the patients with suspected myocarditis to healthy control subjects. They wrote that future trials should include patients with conditions that can appear to be myocarditis, in order to mimic the difficult real-world conditions often faced by clinicians. Nevertheless, they wrote that they are optimistic that cardiovascular magnetic resonance will provide invaluable insights into myocarditis.
Dudley Pennell, M.D., F.A.C.C., at the Royal Brompton Hospital in London, who was not connected with this study, said it is a comprehensive report that gives a fuller picture than earlier studies.
“It gives some insight into which of the techniques is better. One group may say do the T-2, and another group says do the late-gadolinium; this is the first paper that has directly compared them, so it gives us useful information in sorting out what we should be doing in clinical practice,” Dr. Pennell said.
He added that he thinks the results of this study will encourage more institutions to use cardiovascular magnetic resonance imaging to investigate suspected cases of myocarditis.
The American College of Cardiology, a 31,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.