title: The Utility of99mTc-DPD Scintigraphy in the Diagnosis of Cardiac Amyloidosis: An Australian Experience.
abstract: BACKGROUND
  The uptake of bone-seeking radiotracers in the amyloid heart is well recognised. 99mTc-DPD has been shown to be highly sensitive for cardiac transthyretin (ATTR) amyloid in an overseas population, but is not registered for use in Australia. We explored its utility as a diagnostic tool within our population.
  
  
  METHODS
  Patients diagnosed with AL and ATTR (wild-type and inherited) cardiac amyloidosis were prospectively recruited from the Princess Alexandra Hospital Amyloidosis Centre. Patients underwent injection with99mTc-DPD then planar whole body imaging was performed at 5 minutes post-injection (soft tissue phase) and 3 hours (bone phase). A myocardial SPECT and low amperage CT were acquired after the late whole-body scan. Scans were analysed by two nuclear imaging specialists. Intensity of cardiac99mTc-DPD uptake was graded as 0 to 3 in accordance with previous criteria, and semiquantitative analysis was performed using a heart to whole body ratio (H:WB) on the 3-hour scan. Patients also underwent electrocardiography and transthoracic echocardiography, and blood samples were taken for troponin I and brain natriuretic peptide levels, to assess for any correlation with DPD uptake.
  
  
  RESULTS
  Twenty-one patients (8 AL and 13 ATTR) completed the study. Median age was 58 and 70 years for AL and ATTR patients respectively, and 19 (90.5%) were male. 99mTc-DPD scintigraphy was positive in 2 (25%) of AL, and 13 (100%) of ATTR patients. Grade of cardiac uptake, and mean H:WB (0.1249 v. 0.0794) was greater in the ATTR cohort (p-value<0.001 and 0.001 respectively). No statistically significant correlation was identified between H:WB and echocardiographic parameters. There was a significant positive correlation between H:WB and the PR interval on ECG (p=0.026).
  
  
  CONCLUSIONS
  99mTc-DPD scintigraphy is highly sensitive for the diagnosis of cardiac ATTR amyloid, but less so for AL amyloid.
authors.affiliation: Amyloidosis Centre, Princess Alexandra Hospital, Brisbane, Qld, Australia; School of Medicine, University of Queensland, Brisbane, Qld, Australia. Electronic address: Peter.mollee@health.qld.gov.au.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Moore
authors.affiliation: Amyloidosis Centre, Princess Alexandra Hospital, Brisbane, Qld, Australia; School of Medicine, University of Queensland, Brisbane, Qld, Australia.
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Burrage
authors.affiliation: Amyloidosis Centre, Princess Alexandra Hospital, Brisbane, Qld, Australia; School of Medicine, University of Queensland, Brisbane, Qld, Australia.
authors.forename: Emily
authors.initials: E
authors.lastname: Mackenzie
authors.affiliation: Amyloidosis Centre, Princess Alexandra Hospital, Brisbane, Qld, Australia; School of Medicine, University of Queensland, Brisbane, Qld, Australia.
authors.forename: W Philip
authors.initials: WP
authors.lastname: Law
authors.affiliation: Amyloidosis Centre, Princess Alexandra Hospital, Brisbane, Qld, Australia; School of Medicine, University of Queensland, Brisbane, Qld, Australia.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Korczyk
authors.affiliation: Amyloidosis Centre, Princess Alexandra Hospital, Brisbane, Qld, Australia; School of Medicine, University of Queensland, Brisbane, Qld, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Mollee
mesh_terms: D000368:Aged; D028227:Amyloid Neuropathies, Familial / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology; D001315:Australia; D009202:Cardiomyopathies / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D015609:Organotechnetium Compounds / Q000008:administration & dosage*; D013457:Sulfur Compounds / Q000008:administration & dosage*; D014055:Tomography, Emission-Computed; D019210:Troponin I / Q000097:blood
chemical_list: D015609:Organotechnetium Compounds; D013457:Sulfur Compounds; D019210:Troponin I; C471425:technetium 99m 2-methyl-1-(methyl(2-(methyl(2-methyl-2-sulfanylpropyl)amino)ethyl)amino)-2-propanethiol; D020097:Natriuretic Peptide, Brain
keywords: 99(m)Tc-DPD scintigraphy; Bone scan; Cardiac amyloidosis; Nuclear imaging