Noninvasive etiologic diagnosis of cardiac amyloidosis using 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid scintigraphy

J Am Coll Cardiol. 2005 Sep 20;46(6):1076-84. doi: 10.1016/j.jacc.2005.05.073.

Abstract

Objectives: We investigated the diagnostic accuracy of 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) scintigraphy for differentiation of monoclonal immunoglobulin light-chain (AL) and transthyretin (TTR)-related cardiac amyloidosis.

Background: Differential diagnosis between TTR-related and AL amyloidosis is often complex and time-consuming.

Methods: Patients under routine observation with TTR-related/AL systemic amyloidosis and echocardiographic evidence of cardiac involvement were studied with 99mTc-DPD scintigraphy.

Results: Patients with cardiac involvement of TTR-related (group A; n = 15) and AL (group B; n = 10) etiology were comparable for left ventricular mass and renal function. Heart and heart/whole-body tracer retention were significantly higher (p < 0.05) in group A as compared with group B and with 10 unaffected controls. At visual scoring, cardiac 99mTc-DPD uptake was present in all group A patients and absent in all group B patients; thus, using genotyping/immunohistochemistry as the reference technique, the accuracy of 99mTc-DPD scintigraphy for distinction of TTR-related and AL etiology was 100%. Cardiac 99mTc-DPD uptake was also absent among unaffected controls. Using echocardiography as the reference standard for recognition of cardiac involvement, sensitivity and specificity of scintigraphy were both 100% for group A patients; in group B, sensitivity was 0% and specificity was 100% (accuracy, 50%). Eleven patients with myocardial 99mTc-DPD uptake underwent 99mTc-methylene diphosphonate (99mTc-MDP) scintigraphy; all patients showed a 99mTc-MDP myocardial visual score of 0.

Conclusions: Etiology is a third major cause--in addition to type of organ-involved (soft-tissue/heart) and tracer type--of scintigraphic variability in cardiac amyloidosis. This is a highly relevant consideration for future studies. We conclude that 99mTc-DPD scintigraphy is a useful step in the workup of the differential diagnosis of TTR versus AL etiology in patients with documented cardiac amyloidosis.

MeSH terms

  • Aged
  • Amyloidosis / diagnostic imaging*
  • Amyloidosis / etiology*
  • Diagnosis, Differential
  • Diphosphonates*
  • Female
  • Heart Diseases / diagnostic imaging*
  • Heart Diseases / etiology*
  • Humans
  • Immunoglobulin Light Chains
  • Male
  • Middle Aged
  • Organotechnetium Compounds*
  • Prealbumin
  • Radionuclide Imaging
  • Radiopharmaceuticals*
  • Reproducibility of Results

Substances

  • Diphosphonates
  • Immunoglobulin Light Chains
  • Organotechnetium Compounds
  • Prealbumin
  • Radiopharmaceuticals
  • technetium Tc 99m 1,1-diphosphonopropane-2,3-dicarboxylic acid