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Background: We evaluated the diagnostic performance of 18F-NaF PET/MRI in patients with suspected cardiac amyloidosis (CA).Methods: Twenty-seven consecutive patients underwent myocardial PET 1 hour after injection of 4 MBq/kg 18F-NaF with simultaneous MRI including cine-MRI, T1 and T2 mapping, first-pass and late gadolinium enhancement (LGE). 18F-NaF uptake was measured visually and semi-quantitatively by calculating myocardium-to-blood pool (M/B) ratios. CA was confirmed histologically.Results: Transthyretin (TTR)-CA was diagnosed in 16 patients, light-chain (AL)-CA in 7, and no-CA in 4. Visual interpretation of 18F-NaF images revealed a relative increase in myocardial uptake in only 3 patients, all with TTR CA, and a relative decrease in 13, including 7 AL CA, 3 no-CA, and 3 TTR CA. M/B ratios were significantly higher in TTR CA (1.00 ± 0.12) than in AL CA (0.81 ± 0.06, P = 0.001) or in no-CA (0.73 ± 0.16, P = 0.006). The optimal M/B cut-off to distinguish TTR CA from AL CA was ≥ 0.90 (Fischer, P = 0.0005). By comparison, classification of patients using 99mTc-HMDP heart-to-mediastinum ratios with the previously published cut-off ≥ 1.21 reached higher significance (P < 0.0001). Among MRI parameters, myocardial T1, LGE score, and extracellular volume were higher in CA than in no-CA patients, 1409 ± 76 vs 1278 ± 35 ms (P = 0.004), 10.35 ± 5.30 vs 3.50 ± 3.42 (P = 0.03), and 46 ± 10 vs 33 ± 8 % (P = 0.01), respectively.Conclusion: 18F-NaF PET/MRI shows good diagnostic performance when semi-quantification is used. However, contrast is low and visual interpretation may be challenging in routine. PET/MRI could constitute a one-stop-shop evaluation of amyloid load and cardiac function in patients needing rapid work-up. [ABSTRACT FROM AUTHOR]

Background: A decreased longitudinal strain in basal segments with a base-to-apex gradient has been described in patients with cardiac amyloidosis (CA).Objectives: Aim was to investigate the left ventricular (LV) regional distribution of early-phase 99mTc-Hydroxymethylene diphosphonate (99mTc-HMDP) uptake in patients with transthyretin-related cardiac amyloidosis (TTR-CA).Methods: All patients underwent a whole-body planar 99mTc-HMDP scintigraphy acquired at 10-min post-injection (early-phase) followed by a thorax SPECT/CT. The segmental uptake (expressed as % of maximal myocardial HMDP uptake) was investigated on the AHA 17-segment model and 3-segment model (basal, mid-cavity, apical).Results: Sixty-one TTR-CA patients were included of whom 29 were wild-type (wt-TTR-CA) and 32 had hereditary TTR-CA (m-TTR-CA). Early myocardial 99mTc-HMDP uptake occurred in all TTR-CA. In all patients, segmental analysis of the LV myocardial distribution of 99mTc-HMDP uptake showed an increased median uptake (interquartile range) in basal/mid-cavity segments compared to the lowest median uptake of apical segments (respectively, 79% [72%-86%] vs. 72% [64%-81%]; P < 10-6). This pattern was similar in wt-TTR-CA group (78% [70%-84%] vs. 70% [61%-81%]; P < 10-6), in m-TTR-CA group (80% [74%-86%] vs. 73 [66%-82%]; P < 10-7) and remained constant independently of the TTR mutation subtype with P ranging 10-5 to 0.03.Conclusions: Early-phase myocardial scintigraphy identified regional distribution of 99mTc-HMDP uptake characterized by a base-to-apex gradient, corroborating echocardiographic, and cardiac magnetic resonance findings. This apical sparing pattern was similar across TTR-CA and TTR mutation subtypes. [ABSTRACT FROM AUTHOR]

Background: This study sought to compare the intensity of early-phase myocardial uptake of two phosphonate-based radiotracers, 99mTc-hydroxymethylene diphosphonate (HMDP) and 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD), in patients with hereditary transthyretin-related cardiac amyloidosis (TTR-CA).Methods: Six patients with biopsy-proven diagnosis of TTR-CA and characteristic amyloid fibril composition underwent early-phase 99mTc-HMDP myocardial scintigraphy as part of their routine workup; they were later assessed by 99mTc-DPD scintigraphy after having signed informed written consent. Heart-to-mediastinum-ratio was measured at both time points as well as regional distribution on 17-segment analysis.Results: All patients had an H/M ratio >1.28 on both imaging. 99mTc-DPD uptake was slightly higher than 99mTc-HMDP uptake in 3 patients, but no statistical difference was found (P = 0.13). Regional distribution of the two radiotracers was well correlated on bull's eyes analysis, with only slight underestimation of 99mTc-DPD uptake in the anterior/apical segments, compared with 99mTc-HMDP.Conclusion: 99mTc-HMDP and 99mTc-DPD show comparable myocardial uptake intensity on early-phase scintigraphy and can be used alternatively for the diagnosis of TTR-CA. [ABSTRACT FROM AUTHOR]

A 71-year-old African man without history of cardiac disease was referred to our center for dyspnea. Transthoracic echocardiogram and cardiac MRI were suggestive of cardiac amyloidosis (CA). The diagnosis of the light-chain cardiac amyloidosis (AL-CA) was made after a first endomyocardial biopsy. Accordingly chemotherapy was started. Systematic 99mTc-HMDP scintigraphy showed moderate cardiac uptake (visual score of 2), unusual for AL-CA, and permitted to rectify the diagnosis. Hereditary transthyretin cardiac amyloidosis was confirmed by a second endomyocardial biopsy with a positive Congo-red and anti-transthyretin antibody stainings, mass spectrometry and genetic analysis (Val122Ile mutation). [ABSTRACT FROM AUTHOR]