Diagnostic Value of PET in Cardiac Sarcoidosis

TO THE EDITOR:With interest we read the report of Yamagishi et al. (1) comparing the diagnostic value of PET with that of ²⁰¹Tl and ⁶⁷Ga myocardial scintigraphy in 17 patients in whom cardiac sarcoidosis was diagnosed according to the guidelines of the Japanese Ministry of Health and Welfare. The authors concluded that “… PET is the most useful method both for the identification of cardiac involvement of sarcoidosis and for the assessment of cardiac sarcoidosis disease activity.”

Although PET has great potential in the diagnosis and management of this condition, particularly for patients who have had a pacemaker or cardioverter defibrillator implanted, one cannot reach the conclusion the authors did on the basis of a study of 17 patients comparing PET with techniques (²⁰¹Tl and ⁶⁷Ga myocardial scintigraphy) that have been reported to have very limited sensitivity for the diagnosis of cardiac sarcoidosis.

The diagnostic value of PET should rather be assessed in a larger, prospective study using cardiac MRI, PET, and ¹¹¹In-octreotide to evaluate a mixed population of sarcoidosis patients. The experience of Vignaux et al. (2) and our own experience with cardiac MRI in, respectively, 106 and 95 (3,4) sarcoidosis patients has demonstrated a high diagnostic accuracy for cardiac MRI and value in monitoring the response to medical treatment. ¹¹¹In-Octreotide has been reported to be of value in the diagnosis and monitoring of the activity of pulmonary sarcoidosis (5) and is currently being evaluated in a prospective study of cardiac sarcoidosis by our group.