Diagnostic Efficacy of Cardiac Scintigraphy with 99mTc-Pyrophosphate for Latent Myocardial Inflammation in Patients with Atrial Fibrillation

Abstract EN

Objectives.

This work aimed to study the efficacy of hybrid 99mTc-Pyrophosphate SPECT/CT for diagnosis of latent inflammatory processes in the myocardium of patients with atrial fibrillation (AF).

Methods.

The study comprised 34 patients aged 44 ± 9 years with AF of unknown etiology referred for radiofrequency ablation.

The data were acquired using hybrid 99mTc-Pyrophosphate SPECT/CT.

To evaluate and interpret the results of hybrid study and to determine localization of radiopharmaceutical accumulation, scintigraphic and CT images were fused.

SPECT/CT results were compared with data of endomyocardial biopsy.

Results.

Sensitivity, specificity, and accuracy of 99mTc-Pyrophosphate SPECT/CT in diagnosing myocarditis were 91%, 100%, and 94%, respectively.

Proposed diagnostic criteria for myocarditis comprised intensity of the radiopharmaceutical accumulation in the myocardium and the ratios of focus/lung, focus/vertebral column, and focus/LV pool.

Minimum cutoff values for the histologically verified myocarditis were >1.47 for focus/lung index, >0.11 for focus/vertebral column ratio, and >1.26 for focus/lung index.

Conclusions.

SPECT/CT-based quantitative assessment of 99mTc-Pyrophosphate accumulation in the myocardium is a highly informative noninvasive method for diagnosis of inflammatory process in the heart in patients with AF of undefined etiology.