Myocardial stress perfusion-fibrosis imaging pattern in sarcoidosis, assessed by cardiovascular magnetic resonance imaging

Abstract

Sarcoidosis (SRC) is characterized by granulomas in various organs,including the heart [1]. We hypothesized that cardiovascular magneticresonance (CMR) may diagnose silent heart lesions in SRC.Forty five consecutive, asymptomatic patients with SRC, (14 men,45 ± 3 years) normal echocardiogram and 24-hour ECG, underwentCMR imaging, using a 1.5 T. Steady-state, free precession cines wereacquired for function evaluation and STIR T2-W for edema imaging.For SRC with T2 ratiob 2(GroupA)andT2ratioN 2(GroupB),astress perfusion-fibrosis (Fig. 1) and a myocarditis protocol (Fig. 2)were applied, respectively and were compared to 45 age–sexmatched controls.CMRwasperformedin43/45patients(2wereexcludedduetotech-nical reasons). In 34/43 SRC with T2 ratio b 2 (Group A), a stressperfusion-fibrosis CMR revealed a significant reduction in myocardialperfusion reserve index (MPRI), compared to34age–sex matched con-trols(0.95±0.3vs3.5±0.8,p b 0.001).Althoughclearevidenceoflategadolinium enhancement was not identified, the quantitative analysisrevealed diffuse fibrosis in all patients with an extent of 4.5 ± 3.4% LV(range2–15).AvailableCMRafter1yearin18/34patients,documentedLVEF b 50% in 3 patients. Notably, in 6/9 SRC patients with T2 ratio N 2(GroupB),themyocarditis protocol was positive and steroid treatmentwaspromptly given.Sixmonthslater, their CMRwasnormal. Nocorre-lation between CMR, SRC duration and/or other organs involvementwas identified. Detailed CMR parameters of SRC patients are presentedin Table 1.Cardiac involvement, according to pathology, may occur in 20–30%of SRC of patients [1],andhasbeenassociatedwithpoorprognosis[2].Despite these findings, only 5% of SRC have clinical manifestations ofcardiac disease, and only 40–50% of those with cardiac SRC at autopsyhave the correct diagnosis during lifetime [2].CMRhasbeenrecentlyconsideredasthebestnoninvasivetooltoas-sess the presence of fibro-granulomatous tissue in the myocardium inSRC [3]. Smedema et al. reported that the prognosis of asymptomaticSRC patients with cardiac involvement is better compared to SRC pa-tients with symptomatic cardiac SRC [4]. Therefore, a positive CMR inasymptomatic SRC offers the advantage of early treatment and betterprognosis [4]. Greulich et al. found that among SRC with nonspecificsymptoms, myocardial LGE was the best independent predictor of po-tentiallylethalevents[5].IncontrasttoLGEthatdetectstheareaalreadyreplaced by the fibro-granulomatous tissue, sarcoid infiltrates may alsobe visible as increased intramyocardial signal on T2-weighted images,due to edema, associated with granulomatous lesions.In ourasymptomaticSRC, acute myocardialinflammationwasiden-tified by CMR in 14%, characterized by both edema and positive LGE.This was in agreement with previous studies [6] and motivated earlysteroidtreatment;noneofthesteroids-treatedpatientsdevelopedclin-ically overt cardiac SRC in the next 6 months; furthermore, they nor-malized their CMR. Our findings are in agreement with recent data,showing that the prognosis of asymptomatic cardiac involvement inpulmonary SRC remains good [6].Microvascular disease in SRC has been identified in different organs[7]. Reversible myocardial perfusion defects have been already