title: (99m)Tc-pyrophosphate scintigraphy for differentiating light-chain cardiac amyloidosis from the transthyretin-related familial and senile cardiac amyloidoses.
abstract: BACKGROUND
  Differentiating immunoglobulin light-chain (AL) from transthyretin-related cardiac amyloidoses (ATTR) is imperative given implications for prognosis, therapy, and genetic counseling. We validated the discriminatory ability of (99m)Tc-pyrophosphate ((99m)Tc-PYP) scintigraphy in AL versus ATTR.
  
  
  RESULTS
  Forty-five subjects (12 AL, 16 ATTR wild type, and 17 ATTR mutants) underwent (99m)Tc-PYP planar and single-photon positive emission computed tomography cardiac imaging. Scans were performed by experienced nuclear cardiologists blinded to the subjects' cohort assignment. Cardiac retention was assessed with both a semiquantitative visual score (range, 0; no uptake to 3, diffuse uptake) and by quantitative analysis by drawing a region of interest over the heart corrected for contralateral counts and calculating a heart-to-contralateral ratio. Subjects with ATTR cardiac amyloid had a significantly higher semiquantitative cardiac visual score than the AL cohort (2.9±0.06 versus 0.8±0.27; P<0.0001) as well as a higher quantitative score (1.80±0.04 versus 1.21±0.04; P<0.0001). Using a heart-to-contralateral ratio >1.5 consistent with intensely diffuse myocardial tracer retention had a 97% sensitivity and 100% specificity with area under the curve 0.992, P<0.0001 for identifying ATTR cardiac amyloidosis.
  
  
  CONCLUSIONS
  (99m)Tc-PYP cardiac imaging distinguishes AL from ATTR cardiac amyloidosis and may be a simple, widely available method for identifying subjects with ATTR cardiac amyloidosis, which should be studied in a larger prospective manner.
authors: Nuclear Cardiology Laboratory,Columbia College of Physicians & Surgeons, New York, NY, USA.
authors: Sabahat
authors: S
authors: Bokhari
authors: Adam
authors: A
authors: Castaño
authors: Ted
authors: T
authors: Pozniakoff
authors: Susan
authors: S
authors: Deslisle
authors: Farhana
authors: F
authors: Latif
authors: Mathew S
authors: MS
authors: Maurer
mesh_terms: D000368:Aged; D028227:Amyloid Neuropathies, Familial / Q000000981:diagnostic imaging* / Q000235:genetics / Q000628:therapy; D009202:Cardiomyopathies / Q000000981:diagnostic imaging* / Q000235:genetics / Q000628:therapy; D016009:Chi-Square Distribution; D003937:Diagnosis, Differential; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D010641:Phenotype; D011228:Prealbumin / Q000235:genetics*; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016698:Technetium Tc 99m Pyrophosphate; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D011228:Prealbumin; D019275:Radiopharmaceuticals; D016698:Technetium Tc 99m Pyrophosphate
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