Role of 99mTc-DPD Scintigraphy in Diagnosis and Prognosis of Hereditary Transthyretin-Related Cardiac Amyloidosis

Technetium 99m pyrophosphate radioisotope for diagnosis and prognosis of transthyretin cardiac amyloidosis: A call for collaboration

“…2,3 The study confirms the previously reported prognostic value of Tc99m PYP in amyloid cardiomyopathy. 3 The semiquantitative score of 2 or greater coupled with the absence of an abnormal monoclonal protein (ruling out AL cardiac amyloidosis) was shown to be 100% specific for diagnosis of ATTR in an international multicenter collaboration of phosphate-derived radiopharmaceutical imaging in cardiac amyloidosis.…”

“…These findings contradict prior reports. 2,3,7 Among 63 patients with hereditary ATTR in Italy, increased myocardial uptake of the Tc99m PYP-like isotope, (99m)Tc-3,3-diphosphono-1,2-propanodicarboxylic acid (Tc99m DPD), using a heart-to-whole body ratio, was associated with increased left ventricular wall thickness and lower left ventricular ejection fraction (LVEF), in addition to worse MACEfree survival. 2 In a study among 121 patients with suspected cardiac amyloidosis in France (55 ATTR and 14 AL), increased myocardial retention of another Tc99m PYP-like isotope, (99m)Tc-hydroxymethylene diphosphonate (Tc99m HMDP), using a heart-to-skull retention ratio, was associated with lower LVEF and increased acute heart failure and/or death.…”

“…2,3,7 Among 63 patients with hereditary ATTR in Italy, increased myocardial uptake of the Tc99m PYP-like isotope, (99m)Tc-3,3-diphosphono-1,2-propanodicarboxylic acid (Tc99m DPD), using a heart-to-whole body ratio, was associated with increased left ventricular wall thickness and lower left ventricular ejection fraction (LVEF), in addition to worse MACEfree survival. 2 In a study among 121 patients with suspected cardiac amyloidosis in France (55 ATTR and 14 AL), increased myocardial retention of another Tc99m PYP-like isotope, (99m)Tc-hydroxymethylene diphosphonate (Tc99m HMDP), using a heart-to-skull retention ratio, was associated with lower LVEF and increased acute heart failure and/or death. 7 In our own experience among 121 patients with biopsy confirmed ATTR pooled from three centers in the United States, despite a referral population with high pre-test probability of disease and employment of two scan protocols, a Tc99m PYP H/CL ratio of 1.6 or greater was associated with lower LVEF, increased interventricular septal wall thickness, lower stroke volume index, lower myocardial contraction fraction, and worse survival.…”

Nuclear imaging of cardiac amyloidosis

“…Planar imaging alone or with single-photon emission computed tomography (SPECT) using nonamyloid-specific, bone-avid radiotracers ( 99m Tc-DPD [3,3- [8][9][10][11][12][13][14][15][16][17] Recent data indicate that the increased level of microcalcifications may explain the enhanced affinity of bone-seeking tracers for TTR over AL amyloidosis. 18 Amyloidspecific, positron emitting 18 F-and 11 C-tagged tracers have been used successfully with positron emission tomography (PET) imaging for the identification of both AL and TTR subtypes of CA.…”

“…Since the seminal work by Perugini et al 8 , a number of other studies have showed that 99m Tc-DPD and 99m Tc-PYP nuclear imaging is feasible and effective in detecting TTR-CA. 9,11,12,[15][16][17] In addition to the traditionally used qualitative Perugini score which compares myocardial to bone uptake and the semiquantitative HR:WBR, 8 Bokhari et al also showed that 99M Tc-PYP imaging with a heart-to-contralateral lung ratio of [1.5 detected TTR-CA with a 97% and 100% sensitivity and specificity, respectively. 16 Negative and positive example images of TTR-CA with 99M Tc-PYP imaging are depicted in Figures 1 and 2.…”