AUTHOR=Bi Xiao , Xu Baixuan , Liu Jiajin , Wang Guanyun , An Jing , Zhang Xiaojun , Wang Ruimin , Dong Wei , Guan Zhiwei 

TITLE=Diagnostic Value of 11C-PIB PET/MR in Cardiac Amyloidosis

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.830572

DOI=10.3389/fcvm.2022.830572

ISSN=2297-055X

ABSTRACT=<sec><title>Background</title><p>The thioflavin T derivative, <sup>11</sup>C-Pittsburgh-B (PIB), is used for Alzheimer's disease imaging because it specifically binds to β-amyloid protein deposits in the brain. The aim of this study was to estimate the diagnostic value of combined <sup>11</sup>C-PIB positron emission tomography/magnetic resonance (PET/MR) in cardiac amyloidosis (CA).</p></sec><sec><title>Methods</title><p>We enrolled 23 heart failure patients with suspected CA based on echocardiographic and electrocardiograph findings. All patients underwent cardiac <sup>11</sup>C-PIB PET/MR and non-cardiac biopsy within one week. We also enrolled eight healthy volunteers that underwent cardiac <sup>11</sup>C-PIB PET/MR as a control group. The cardiac magnetic resonance (CMR) protocol included cine imaging, late gadolinium enhancement (LGE), and native and post-contrast T1 mapping. Extracellular volume (ECV) was measured using pre- and post-contrast T1 mapping images. LVEF, IVSD, LVPW, LVmass, LVESV, LVEDV, native T1 value, ECV, and maximum uptake of myocardial tissue-to-blood background ratio (TBR) values were obtained from PET/MR images in all patients and healthy subjects.</p></sec><sec><title>Results</title><p>Thirteen out of twenty-three heart failure patients were clinically diagnosed with CA. The remaining 10 patients were CA-negative (non-CA patient group). Twelve of the thirteen CA patients showed diffuse transmural LGE patterns, whereas LGE was either absent or patchy in the non-CA patients. The diagnostic sensitivity and specificity of TBRmax were 92.3 and 100%, respectively, at a cut-off value of 1.09. Several CMR imaging parameters (LVEF, IVSD, LVmass, LVEDV, LVESV, LVPW, native T1 value and ECV) and TBR showed significant differences between CA patients, non-CA patients, and healthy controls (<italic>P</italic> &lt; 0.05). Native T1 mapping values positively correlated with TBRmax values in CA and non-CA patients (<italic>r</italic> = 0.38, <italic>P</italic> = 0.0004).</p></sec><sec><title>Conclusions</title><p><sup>11</sup>C-PIB PET/MRI is a valuable tool for the accurate and non-invasive diagnosis of CA because it distinguishes CA patients from non-CA patients and healthy subjects with high specificity and sensitivity. Moreover, native T1 mapping values positively correlated with TBRmax values in CA and non-CA patients. In the future, larger cohort studies are necessary to confirm our findings.</p></sec>