title: Role of cardiac scintigraphy with ⁹⁹mTc-DPD in the differentiation of cardiac amyloidosis subtype.
abstract: OBJECTIVE
  We investigated the diagnostic accuracy of (99m)Tc-3,3-diphosphono-1,2 propanodicarboxylic acid ((99m)Tc-DPD) scintigraphy in differentiating between monoclonal immunoglobulin light chain and transthyretin-related cardiac amyloidosis.
  
  
  METHODS
  Nineteen patients with documented cardiac amyloidosis were included: 8 with transthyretin-related amyloidosis (group A) and 11 with light chain amyloidosis (group B). All the patients underwent scintigraphy with (99m)Tc-DPD and (99m)Tc-methylene diphosphonate ((99m)Tc-MDP).
  
  
  RESULTS
  On visual scoring, cardiac (99m)Tc-DPD uptake could be characterized as moderate to severe (scores of 2-3), with ventricular or biventricular distribution, in all group A patients (transthyretin-related cardiac amyloidosis), and was absent or mild (scores of 0-1) and diffusely distributed in all group B patients (monoclonal immunoglobulin light chain cardiac amyloidosis). (99m)Tc-DPD uptake was also absent (score of 0) among unaffected controls and in 2 unaffected relatives of patients with hereditary transthyretin-related amyloidosis who harbor a mutation in the TTR gene. With (99m)Tc-MDP, all the patients had a myocardial uptake score of 0-1. In our series, selective myocardial uptake of (99m)Tc-DPD provided 100% accuracy (95% confidence interval, 97.37%-100%) for the differentiation between transthyretin-related and monoclonal immunoglobulin light chain cardiac amyloidosis.
  
  
  CONCLUSIONS
  We conclude that (99m)Tc-DPD scintigraphy is a useful test for the differential diagnosis of transthyretin vs monoclonal immunoglobulin light chain etiology in patients with cardiac amyloidosis.
authors.affiliation: Servicio de Medicina Nuclear, Hospital Universitario Puerta de Hierro, Majadahonda, Madrid, Spain. fjdeharo.hpth@salud.madrid.org
authors.forename: F Javier
authors.initials: FJ
authors.lastname: de Haro-del Moral
authors.forename: Alicia
authors.initials: A
authors.lastname: Sánchez-Lajusticia
authors.forename: Manuel
authors.initials: M
authors.lastname: Gómez-Bueno
authors.forename: Pablo
authors.initials: P
authors.lastname: García-Pavía
authors.forename: Clara
authors.initials: C
authors.lastname: Salas-Antón
authors.forename: Javier
authors.initials: J
authors.lastname: Segovia-Cubero
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000686:Amyloidosis / Q000000981:diagnostic imaging*; D009202:Cardiomyopathies / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D004164:Diphosphonates; D005260:Female; D006801:Humans; D007147:Immunoglobulin Light Chains; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010265:Paraproteinemias / Q000000981:diagnostic imaging*; D011228:Prealbumin / Q000235:genetics; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals
chemical_list: D004164:Diphosphonates; D007147:Immunoglobulin Light Chains; D015609:Organotechnetium Compounds; D011228:Prealbumin; D019275:Radiopharmaceuticals; C033905:technetium Tc 99m 1,1-diphosphonopropane-2,3-dicarboxylic acid