A varying degree of interstitial and perivascular fibrosis is a common finding in idiopathic dilated cardiomyopathy (DCM). The perfusable tissue index (PTI), obtained with PET, is a non-invasive tool for assessing myocardial fibrosis on a regional level. Measurements of the PTI in DCM, however, have not been performed yet. This study was undertaken to test the hypothesis that the PTI is reduced in patients with DCM. Methods: Fifteen patients with an advanced stage of DCM (New York Heart Association class III or IV and left ventricular ejection fraction [LVEF] < 35%) and 11 healthy control subjects were studied. PET was performed using H2 15O and C15O to obtain the perfusable tissue fraction (PTF) and the anatomic tissue fraction (ATF), respectively. Results: The PTI (=PTF/ATF) was reduced in DCM compared with control subjects (0.91 ± 0.12 vs. 1.12 ± 0.10; P < 0.01). Heterogeneity of the PTI, expressed as the coefficient of variation, was increased in DCM versus that of healthy control subjects (0.18 ± 0.07 vs. 0.13 ± 0.06; P < 0.05). There was no correlation between the PTI and echocardiographically derived LVEF in both groups. Conclusion: The PTI was reduced in patients with an advanced stage of DCM. Interstitial and perivascular fibrosis may be responsible for this reduction. Furthermore, the degree of the PTI reduction was variable in DCM patients, both on a regional level and between patients. Noninvasive assessment of fibrosis with the PTI offers the opportunity to evaluate the effects of fibrosis on regional myocardial function, correlate fibrosis with prognosis, and monitor pharmaceutical intervention.
|Number of pages||6|
|Journal||Journal of Nuclear Medicine|
|Publication status||Published - 1 Aug 2004|