Hepatic and myocardial iron quantification can be performed noninvasively with MRI. MRI can quantify a parameter called "T2*", which is an indicator of the amount of iron in the liver and myocardium. The smaller the T2*, the greater then iron deposition. For exams performed on 1.5 Tesla magnets, T2* < 5 milliseconds indicates severe iron overload, 5 < T2* < 10 milliseconds indicates moderate iron overload, 10 < T2* < 20 milliseconds reflects mild overload, and T2* > 20 milliseconds is normal. The reciprocal of T2* is referred to as R2*, i.e. R2* = 1/T2*. Liver and myocardial iron concentration is directly proportional to R2*. This, MRI may be used to diagnose iron overload, and to noninvasively guide chelation therapy in the setting of iron overload. While MRI is accurate in this assessment, obtaining good results requires performance at a center with experience and requires attention to technical details.
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Last modified Thu, 9 Aug, 2012 at 15:16