ABSTRACT
Objective:To investigate the application of different imaging methods of 99Tc m-pyrophosphate (PYP) in the diagnosis and pathological classification of cardiac amyloidosis (CA). Methods:A total of 31 patients (22 males, 9 females, age 21-81(57.2±13.4) years) with suspected CA who underwent 99Tc m-PYP dual-phase scintigraphy (early-phase: 1 h, delay-phase: 2-3 h) and SPECT/CT (1 h) between December 2018 and December 2019 in Peking Union Medical College Hospital were retrospectively included. Taking clinical diagnosis as the standard, the results of visual score (≥2, positive) and semi-quantitative values (heart to contralateral lung (H/CL)≥1.5, positive) of 99Tc m-PYP uptake in dual-phase scintigraphy and SPECT/CT imaging were analyzed. One-way analysis of variance and Bonferroni test were used to analyze the data. Results:Among 31 patients with suspected CA, 15 were clinically diagnosed as CA (5 patients with transthyretin-related CA (ATTR-CA) and 10 patients with light chain CA (AL-CA)) and 16 were diagnosed as non-CA. All 5 patients with ATTR-CA had positive dual-phase scintigraphy and SPECT/CT imaging results. Three out of 10 patients with AL-CA had positive early-phase scintigraphy whereas negative delay-phase scintigraphy and SPECT/CT imaging results. Sixteen patients who were clinically diagnosed as non-CA had negative dual-phase scintigraphy and SPECT/CT imaging results. The sensitivity (5/5), specificity (10/10), positive predictive value (5/5), negative predictive value (10/10) and accuracy (15/15) of delay-phase scintigraphy and SPECT/CT imaging were the same. Among 31 patients, 16 patients carried transthyretin-related (TTR) gene mutation, and 4 of them who clinically diagnosed as variant ATTR (ATTRv) had positive image findings while 12 of them who not clinically diagnosed as CA had negative image findings. There were significant differences in H/CL between ATTR-CA group and AL-CA group in early-phase (2.11±0.24 vs 1.31±0.07) and delay-phase (2.02±0.19 vs 1.30±0.05; F values: 75.41 and 87.15, Bonferroni test, both P<0.01). Conclusions:99Tc m-PYP delay-phase scintigraphy and SPECT/CT have high diagnostic efficiencies in ATTR-CA, helping to determine the pathological classification of CA; while early-phase scintigraphy has false positive results. Moreover, 99Tc m-PYP imaging is helpful to detect CA in patients with TTR gene mutation.
ABSTRACT
Objective:To evaluate the diagnostic value of 99Tc m-pyrophosphate (PYP) in transthyretin cardiac amyloidosis. Methods:From December 2018 to July 2019, 17 patients (9 males, 8 females, age: (53.4±13.0) years) with suspected cardiac amyloidosis underwent 99Tc m-PYP imaging in Peking Union Medical College Hospital were prospectively included. Visual score and semi-quantitative values (heart to contralateral ratio, H/CL) of 99Tc m-PYP uptake were used to diagnose transthyretin amyloidosis (ATTR). Biopsies and genetic measurements were also developed to evaluate the diagnostic value of the imaging. Results:Five of the 17 patients were diagnosed as ATTR with a visual score of 2-3, H/CL≥1.5, and confirmed with the biopsy or gene test. Four patients were diagnosed as ATTR with positive genetic results but no cardiac symptoms, and their visual scores were between 0 and 1 with H/CL<1.5. Considering the young age of the patients, amyloid deposition might have not yet caused visceral damage. Visual score of other 8 patients with negative 99Tc m-PYP imaging were also between 0 and 1 with H/CL<1.5, 2 of 8 were confirmed with light chain amyloidosis (AL) by biopsy, 3 were clinically diagnosed as AL and 3 were ATTR excluded. The accuracy of 99Tc m-PYP imaging for diagnosing ATTR was 11/11. Conclusion:99Tc m-PYP imaging is helpful for non-invasive diagnosis of transthyretin cardiac amyloidosis.
ABSTRACT
Amyloidosis is a disease caused by abnormal deposition of amyloid protein, and the main types of amyloidosis involving myocardium are light chain amyloidosis (AL) and transthyretin-related amyloidosis (ATTR). Different types of myocardial amyloidosis have different prognosis and treatment methods. Therefore, early diagnosis and classification are particularly important. Nuclear medical imaging can diagnose and classify myocardial amyloidosis noninvasively. Radiotracers for bone scintigraphy has high sensitivity and specificity for the diagnosis of ATTR, and have certain value for prognosis. Sympathetic innervation imaging tracers can detect cardiac sympathetic innervation, which may show myocardial involvement of amyloidosis earlier than bone scintigraphy. Amyloid protein specific imaging agent, which was first used in the diagnosis of amyloidosis in nervous system, has also yielded good results from preliminary studies in myocardial amyloidosis, and the diagnostic specificity in AL is slightly better than that in ATTR. This review introduces the application of nuclear medical imaging in myocardial amyloidosis.
ABSTRACT
Amyloidosis is a disease caused by abnormal deposition of amyloid protein, and the main types of amyloidosis involving myocardium are light chain amyloidosis (AL) and transthyretin-related amy-loidosis (ATTR). Different types of myocardial amyloidosis have different prognosis and treatment methods. Therefore, early diagnosis and classification are particularly important. Nuclear medical imaging can diag-nose and classify myocardial amyloidosis noninvasively. Radiotracers for bone scintigraphy has high sensitivi-ty and specificity for the diagnosis of ATTR, and have certain value for prognosis. Sympathetic innervation imaging tracers can detect cardiac sympathetic innervation, which may show myocardial involvement of amy-loidosis earlier than bone scintigraphy. Amyloid protein specific imaging agent, which was first used in the diagnosis of amyloidosis in nervous system, has also yielded good results from preliminary studies in myocar-dial amyloidosis, and the diagnostic specificity in AL is slightly better than that in ATTR. This review intro-duces the application of nuclear medical imaging in myocardial amyloidosis.