Hi Jos
The necessity of MRI does not related to the level of HB but rather related to the elevated serum ferritin.
Having a high ferritn may indicate having iron overloaded in organs such as liver, heart, pancreas,.. so an MRI is important to know if these organ have iron in them or not.
One very important note, is that in intermeidas (which is supposed to be the case according to your mutation, but it is not according to your HB level
) serum ferritin is not a reliable measure to indicate iron overload in organ.
The level of ferritin could be the same in two patients (one is major and the other is intermedias),but when you do an MRI, you can find that there is an iron overload in the organs of the intermedia patient.
So to su up, serum ferritin is not a reliable indication for iron overload in organs in intermedia mutations, that is why an MRI is essential for you.
T2* is the name of the scan made on the heart to show if there is iron deposits in heart or not. It is exactly like an MRI on the heart
manal