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

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

doi:10.3389/fcvm.2022.830572

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

Front Cardiovasc Med. 2022 Mar 16:9:830572. doi: 10.3389/fcvm.2022.830572. eCollection 2022.

Authors

Xiao Bi¹, Baixuan Xu¹, Jiajin Liu¹, Guanyun Wang¹, Jing An², Xiaojun Zhang¹, Ruimin Wang¹, Wei Dong³, Zhiwei Guan^{1

4}

Affiliations

¹ Department of Nuclear Medicine, The First Medical Centre, Chinese PLA General Hospital, Beijing, China.
² Department of Cardiology, The Sixth Medical Centre, Chinese PLA General Hospital, Beijing, China.
³ Siemens Healthcare Ltd., Guangdong, China.
⁴ National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing, China.

Abstract

Background: The thioflavin T derivative, ¹¹C-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 ¹¹C-PIB positron emission tomography/magnetic resonance (PET/MR) in cardiac amyloidosis (CA).

Methods: We enrolled 23 heart failure patients with suspected CA based on echocardiographic and electrocardiograph findings. All patients underwent cardiac ¹¹C-PIB PET/MR and non-cardiac biopsy within one week. We also enrolled eight healthy volunteers that underwent cardiac ¹¹C-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.

Results: 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 (P < 0.05). Native T1 mapping values positively correlated with TBRmax values in CA and non-CA patients (r = 0.38, P = 0.0004).

Conclusions: ¹¹C-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.

Keywords: 11C-PIB; ECV; LGE; PET/MR; TBR; cardiac amyloidosis; non-invasive diagnosis.