Computed tomographic appearances of cardiac amyloidosis.

Computed tomography was used to identify the characteristic appearances of histologically confirmed cardiac amyloidosis in two patients. Mean myocardial density and 95% confidence limits in one of these patients (30.6 +/- 3.4 Hounsfield units (HU) ) were significantly lower than in patients with diffuse hypertrophic cardiomyopathy (range from 38.8 +/- 5.7 HU to 45.9 +/- 4.4 HU) and normal myocardium (range from 41.9 +/- 4.3 HU to 44.8 +/- 4.4 HU) on pre-contrast computed tomograms. Although only an approximate myocardial density was obtained in the second patient with amyloidosis, a similar result (30 HU) was noted on pre-contrast tomograms. Diffuse thickening of the interventricular septum and left ventricular free wall was found in both patients. Myocardial density on post-contrast computed tomograms was 102.8 +/- 5.2 HU in one patient and approximately 100 HU in the other. A pericardial effusion was noted in the first patient. A low myocardial density on pre-contrast tomograms and diffuse myocardial thickening on post-contrast tomograms are considered to be important features of cardiac amyloidosis.