DIFERENCIAS FISIOLÓGICAS EN LA CAPTACIÓN ÓSEA DE [99mTc]Tc-PIROFOSFATO EN HOMBRES Y MUJERES SOMETIDOS A...

Cardiac amyloidosis (CA) is one of the causes of restrictive cardiomyopathy. [^99mTc]Tc-pyrophosphate (PYP) is a sensitive diagnostic tool in diagnosing transthyretin CA. This multicenter retrospective study evaluated whether bone uptake can serve as a reliable reference in [99mTc]Tc-pyrophosphate (PYP) scintigraphy for cardiac amyloidosis (CA). Cases with heart failure preserved ejection fraction whose 99mTc PYP scintigraphy images were evaluated as negative for CA involvement, obtained from two dedicated centers, were included in this retrospective study. AL amyloidosis was ruled out in all patients according to serum/urine laboratory test results. On SPECT images, ROI was drawn over the thoracic vertebral body as bone (B), lung (L), left ventricular cavity as blood pool (BP), interventricular septum (IS), liver (LV), and paraspinal muscle as soft tissue (ST). Counts, volumes; maximum, mean, and minimum standardized uptake values (SUVmax, SUVmean, and SUVmin, respectively) of each ROI were recorded. Counts were corrected according to volumes. A Total of 191 cases (Center 1: n = 92, Center 2: n = 99) were included in the study. Median ages were 68. No significant difference was detected in terms of age and gender between the two centers. When evaluating all cases, B counts, B SUVmean, and BP values were significantly higher in women (p < 0.05). B counts and B SUVmean did not differ between centers and demonstrated a strong correlation between 1h and 3h images (ρ = 0.75, p < 0.001). These findings indicate that bone uptake is stable across centers and time points, supporting its role as a quantitative reference, although higher uptake in women may challenge visual interpretation.