Sagittal MRI of the heart in three patients with homozygous β thalassemia and transfusional iron overload. (A, left) Normal signal from the septum (long arrow) and posterior wall of the heart, consistent with the presence of very mild cardiac iron loading, in a transfused patient regularly complianct with iron chelating therapy. The homogenous signal of the liver, consistent with very mild iron loading in this organ (short arrow), is also seen below the image of the heart. (B, middle): Imhomogenity of signal from the septum (long arrow) and posterior wall, consistent with moderate iron deposition in a transfused patient erratically compliant with iron chelating therapy. Loss of liver signal (short arrow) is consistent with heavier iron loading in this organ. (C, right): Absence of signal from the septum (arrow), posterior wall and liver (short arrow), compatible with heavy iron deposition in a transfused patient who has been noncompliant with iron chelating therapy over several years.