(11)C-PiB PET/MRI在原发性系统性轻链型淀粉样变器官受累评估中的价值

OBJECTIVE: To analyze the value of (11)C-PiB PET/MRI for evaluating organ involvement in patients with primary light chain amyloidosis（pAL）. METHODS: The clinical data of 20 patients with pAL and 3 healthy volunteers from January 2019 to October 2021 were retrospectively analyzed. The correlation between the organ involvement evaluated by clinical standards and PET/MRI was compared. The relationship between cardiac-related biological indicators, disease stage, and the maximum standardized uptake value（SUVmax）were analyzed. The relationship between 24-hour urinary protein quantification and kidney SUVmax was analyzed. RESULTS: ①In 20 patients (18 newly diagnosed patients and 2 non-newly diagnosed patients), (11)C-PiB positive uptake was observed in the heart（15 patients, 75％）, lung（8 patients, 40％）, bone marrow（10 patients, 50％）, muscle（10 patients, 50％）, tongue muscle（7 patients, 35％）, thyroid（6 patients, 30％）, salivary gland（4 patients, 20％）, spleen（2 patients, 10％）, and stomach wall（1 patient, 5％）. ②Organ involvement on (11)C-PiB PET/MRI showed good correlations with the clinical evaluation criteria for the heart and bone marrow. The positive rate of PET/MRI evaluation in the lung, spleen, gland, muscle, and tongue muscle was significantly higher than the clinical criteria. However, (11)C-PiB PET/MRI has limitations in the evaluation of the nervous system and fat tissue. ③To analyze the relationship between cardiac-related biological indexes and the SUVmax of the heart in 13 newly diagnosed patients. Patients with left ventricular ejection fraction（LVEF）<50％ and interventricular septal thickness（ISV）≥1.2 cm showed a higher SUVmax than patients with LVEF ≥50％ and ISV<1.2 cm（P<0.05）.There are significant differences in the SUVmax of the heart between the Mayo2004 stage and the Mayo2012 stage. The later the disease stage, the higher the SUVmax（P<0.05）. The SUVmax of the heart was positively correlated with cardiac troponin I（cTnI）and N-terminal pro-brain natriuretic peptide（NT-proBNP）（P<0.01）.There was no significant correlation between renal SUVmax and 24-hour urine protein（P>0.05）. CONCLUSION: Whole body (11)C-PiB PET/MRI, as a visualization system of amyloid protein, is used to qualitatively evaluate organ involvement, which can improve the level of early non-invasive diagnosis. Whole body (11)C-PiB PET/MRI can be used to perform quantitative evaluation of organ levels, especially the heart, which is expected to evaluate organ function and predict disease prognosis more accurately.