Absolute quantification of myocardial uptake of 99mTc-DPD in patients with cardiac amyloidosis due to transthyretin deposits (ATTR)

Abstract

Purpose

To determine the diagnostic contribution of the absolute quantification of the myocardial deposit of ^99mTc-DPD in patients with cardiac amyloidosis due to transthyretin deposits (ATTR).

Materials and methods

SPECT/CT was performed in 41 patients with positive scintigraphic results for ATTR cardiac amyloidosis. The patients were divided into two groups (Perugini grades 2 and 3) and the SUVmax at the level of the bone and both ventricles and the percentage of dose calculated in these areas were calculated. The Student's t-test was used to compare results and the area under the curve (AUC) was calculated to assess differential efficacy and establish discriminatory cut-off points between both groups of patients.

Results

Statistically significant differences were observed in all the study variables, with the exception of bone SUV_max. The differences with the greatest statistical power were observed in the variables SUV_maxRV and the percentage of dose in both ventricles (p < 0.001). The cut-off point obtained for the variable SUVm_axLV was 8.620 (sensitivity 87.9% and specificity 100%; AUC 0.966), while that of the variable SUV_maxRV was 6.195 (sensitivity 81.8% and specificity 100%; AUC 0.955).

Conclusions

The absolute quantification of myocardial uptake of ^99mTc-DPD in the SPECT/CT images of patients with suspected cardiac amyloidosis due to transthyretin deposits represents a new diagnostic tool that allows adequate classification of patients according to the Perugini visual grading scale.