Author + information
- Received March 4, 2005
- Revision received May 18, 2005
- Accepted May 24, 2005
- Published online September 20, 2005.
- Enrica Perugini, MD⁎,
- Pier Luigi Guidalotti, MD†,
- Fabrizio Salvi, MD‡,
- Robin M.T. Cooke, MA⁎,
- Cinzia Pettinato, MD†,
- Letizia Riva, MD⁎,
- Ornella Leone, MD§,
- Mohsen Farsad, MD†,
- Paolo Ciliberti, MD⁎,
- Letizia Bacchi-Reggiani, MSc, MBiostat⁎,
- Francesco Fallani, MD⁎,
- Angelo Branzi, MD⁎ and
- Claudio Rapezzi, MD⁎,⁎ ()
- ↵⁎Reprint requests and correspondence:
Prof. Claudio Rapezzi, Istituto di Cardiologia, Policlinico S. Orsola-Malpighi, via Massarenti 9, 40138 Bologna, Italy.
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.
- Received March 4, 2005.
- Revision received May 18, 2005.
- Accepted May 24, 2005.
- American College of Cardiology Foundation