Myocardial iodine concentration measurement using dual-energy computed tomography for the diagnosis of cardiac amyloidosis: a pilot study

To measure myocardium iodine concentration (MIC) in patients with cardiac amyloidosis (CA) using dual-energy computed tomography (DECT). Twenty-two patients with CA, 13 with non-amyloid hypertrophic cardiomyopathies (CH) and 10 control patients were explored with pre-contrast, arterial and 5-minute DECT acquisition (Iomeprol; 1.5 mL/kg). Inter-ventricular septum (IVS) thickness, blood pool iodine concentration (BPIC), MIC (mg/mL), iodine ratio and extra-cellular volume (ECV) were calculated. IVS thickness was significantly (p < 0.001) higher in CA (17 +/- 4 mm) and CH (15 +/- 3 mm) patients than in control patients (10 +/- 1 mm). CA patients exhibited significantly (p < 0.001) higher 5-minute MIC [2.6 (2.3-3.1) mg/mL], 5-minute iodine ratio (0.88 +/- 0.12) and ECV (0.56 +/- 0.07) than CH [1.7 (1.4-2.2) mg/mL, 0.57 +/- 0.07 and 0.36 +/- 0.05, respectively] and control patients [1.9 (1.7-2.4) mg/mL, 0.58 +/- 0.07 and 0.35 +/- 0.04, respectively). CH and control patients exhibited similar values (p = 0.9). The area under the curve of 5-minute iodine ratio for the differential diagnosis of CA from CH patients was 0.99 (0.73-1.0; p = 0.001). With a threshold of 0.65, the sensitivity and specificity of 5-minute iodine ratio were 100% and 92%, respectively. Five-minute MIC and iodine ratio were increased in CA patients and exhibited best diagnosis performance to diagnose CA in comparison to other parameters.