A computer-implemented method of detecting myocardial iron content using black-blood magnetic resonance imaging data, comprising: fitting contours to the epicardial and endocardial margins of the left ventricle in the imaging data; creating a binary map by segmenting voxels of the imaging data according to whether the voxel values are above or below a threshold, the threshold being chosen so as to distinguish between blood and ventricular tissue; using the created binary map and the fitted contours to identify the portion of the tissue between the fitted contours corresponding to the interventricular septum; and detecting myocardial iron content by performing T2* measurements on a portion of the imaging data corresponding to the identified interventricular septum, wherein the step of fitting contours comprises: an initialization step in which two circles are fitted to the imaging data, a first of the circles being fitted to the epicardial margin of the left ventricle and a second of the circles being fitted to the endocardial margin of the left ventricle; and an adjustment step in which the fitted circles are iteratively adjusted to fit the respective margins of the left ventricle, and wherein the adjustment step comprises the following steps: a first adjustment step comprising iteratively adjusting the fitted circles to obtain first estimated contours of the left ventricle; a second adjustment step comprising fitting an ellipse to each of the first estimated contours obtained in the first adjustment step, thereby obtaining first estimated ellipses; and a third adjustment step comprising obtaining second estimated contours as the margins of the portion of the myocardium that is enclosed by both said first estimated contours and said first estimated ellipses. fitting contours to the epicardial and endocardial margins of the left ventricle in the imaging data; creating a binary map by segmenting voxels of the imaging data according to whether the voxel values are above or below a threshold, the threshold being chosen so as to distinguish between blood and ventricular tissue; using the created binary map and the fitted contours to identify the portion of the tissue between the fitted contours corresponding to the interventricular septum; and detecting myocardial iron content by performing T2* measurements on a portion of the imaging data corresponding to the identified interventricular septum, wherein the step of fitting contours comprises: an initialization step in which two circles are fitted to the imaging data, a first of the circles being fitted to the epicardial margin of the left ventricle and a second of the circles being fitted to the endocardial margin of the left ventricle; and an adjustment step in which the fitted circles are iteratively adjusted to fit the respective margins of the left ventricle, an initialization step in which two circles are fitted to the imaging data, a first of the circles being fitted to the epicardial margin of the left ventricle and a second of the circles being fitted to the endocardial margin of the left ventricle; and an adjustment step in which the fitted circles are iteratively adjusted to fit the respective margins of the left ventricle, and wherein the adjustment step comprises the following steps: a first adjustment step comprising iteratively adjusting the fitted circles to obtain first estimated contours of the left ventricle; a second adjustment step comprising fitting an ellipse to each of the first estimated contours obtained in the first adjustment step, thereby obtaining first estimated ellipses; and a third adjustment step comprising obtaining second estimated contours as the margins of the portion of the myocardium that is enclosed by both said first estimated contours and said first estimated ellipses. a first adjustment step comprising iteratively adjusting the fitted circles to obtain first estimated contours of the left ventricle; a second adjustment step comprising fitting an ellipse to each of the first estimated contours obtained in the first adjustment step, thereby obtaining first estimated ellipses; and a third adjustment step comprising obtaining second estimated contours as the margins of the portion of the myocardium that is enclosed by both said first estimated contours and said first estimated ellipses.