Clinical significance of quantitative bone SPECT measurement for left ventricular myocardial deformation in patients with cardiac amyloidosis

1640 Purpose: Transthyretin cardiac amyloidosis (ATTR) is characterized by left ventricular hypertrophy and conduction abnormality due to amyloid deposition, and associated with poor prognosis. We aimed to clarify the relationship of bone tracer uptake and myocardial deformation in patients with ATTR using quantitative measurement with quantitative xSPECT/CT system.\n Methods: Fifteen consecutive ATTR patients (age 77±7, male 12) who underwent 99mTc hydroxymethylene diphosphonate bone SPECT (HDMP-SPECT) were retrospectively enrolled. Heart/Contralateral lung ratio (H/CL) and standardized 0-3 point visual grading were obtained from planar image. Myocardial SUVmax, SUVpeak, and uptake volume (MUV cm3, the volume of SUV\u003e2.5) were quantitatively measured using xSPECT system (Intevo®, Siemens, Enlargen). The data were compared to QRS duration of electrocardiogram and cardiac transthoracic echocardiography data (left ventricular ejection fraction = LVEF, end-diastolic dimension = LVDd, and septal wall thickness = LVWT).\n Results: In all patients, SUVmax, SUVpeak, and MUV were 4.2±1.9, 3.6±1.7, and 148±150cm3. All data showed significant positive correlation with H/CL and visual grading (r=0.7, 0.7, 0.7, p=0.003, 0.001, and 0.009 with H/CL; r=0.7, 0.8, 0.5, p=0.0009, 0.0004, and 0.05 with visual grading, respectively). MUV showed significant correlation to QRS duration (r=0.6, p=0.04) while SUVmax and SUVpeak did not. MUV also showed significant positive correlation with WT (r=0.6, p=0.02). None of obtained quantitative data showed significant correlation to LVEF, and LVDd.\n Conclusions: Quantitative volume measurement of HDMP-SPECT significantly correlated to conventional semi-quantitative analysis in ATTR patients. The quantitative analysis was also associated with myocardial deformation.