Thal Pals Comic #16
June 22, 2009 – Maria has her T2* results back.
Next episode will be posted on 07/06/09.
Funding for Thal Pals comes from an unrestricted educational grant from Novartis Pharmaceuticals. Story – Craig Butler. Art- John Thornton. Copyright 2009 by Cooley’s Anemia Foundation.
|What is T2*?|
| (The following information on T2* is reprinted from the September 2007 CAF MEDICAL UPDATE.)
People with thalassemia are encouraged to
get T2* measurements to help assess their
cardiac health. What is a T2*?
T2* is the measure of how fast an MRI image of
the heart darkens.
When a person gets a T2* score, exactly what
is that score measuring?
The lower the T2*, the greater the amount of
iron in the heart. (Editor’s note: T2* provides a
measurement that reflects the amount of iron
in the heart.) A T2* greater than 20 ms means
that there is no detectable cardiac iron. The
risk of heart trouble increases steeply as heart
T2* falls below 10 ms. Having an abnormal T2*
is like having an abnormal cholesterol. Many
patients with elevated cholesterol feel fine and
have normal heart function….but they are at
higher risk over time.
Is the MRI measuring the amount of iron in
the heart, or is it providing a different kind of
It depends. Variation in T2* for values greater than 20 ms can reflect differences in factors
besides iron, such as blood flow, cardiac
motion, and image artifacts. However, changes
in T2* for values less than 20 ms are
determined almost exclusively by tissue iron.
Sometimes, a person may have a T2* score
that is low enough to cause concern, but
his/her serum ferritin may be at a very
reasonable level and s/he may have a clear
echo. How concerned should a person in
this situation be?
High ferritin values and high liver iron
concentrations should always be concerning,
regardless of the heart T2* value. However,
the converse is also true. Some patients have
severe cardiac iron deposition (low T2*) and
heart problems, despite apparently good
chelation as measured by ferritin and liver iron
values. The situation of high heart iron with
low liver iron occurs because the heart and
liver take up and release iron at different rates
and by different chemical pathways. These
patients need changes in their chelation
regimen to specifically improve their cardiac
chelation, such as 24/7 Desferal (Desferal
administered 24 hours a day/7 days a week)or
oral chelation therapy, with careful observation
to prevent overchelation.
In situations where there is a low T2* and a
clear echo, what do you recommend the
patient do? Should chelation regimens be
A low cardiac T2* should prompt a complete
review of the patient’s transfusion and chelation regimens, as well as the ferritin and liver iron histories. The change in cardiac T2* over time is much more helpful than a single value. If the
cardiac T2* is improving (rising) and the patient has normal function, no change in the chelation regimen is necessarily indicated.
If no action is taken, how soon until you
observe changes in the echo indicating a
serious cardiac condition?
The time between detection of an abnormal
heart T2* and development of new
echocardiogram abnormalities has not been
well characterized. It is on the order of a few
months to a few years and appears to be
shorter for higher cardiac iron levels. Waiting
until echocardiographic parameters change,
however, is a bad idea because not all patients
can be rescued with intensive chelation.
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