Extracellular volume quantification by dynamic equilibrium cardiac computed tomography in cardiac amyloidosis

J Cardiovasc Comput Tomogr. Nov-Dec 2015;9(6):585-92. doi: 10.1016/j.jcct.2015.07.001. Epub 2015 Jul 10.

Abstract

Background: Cardiac involvement determines outcome in patients with systemic amyloidosis. There is major unmet need for quantification of cardiac amyloid burden, which is currently only met in part through semi-quantitative bone scintigraphy or Cardiovascular Magnetic Resonance (CMR), which measures ECVCMR. Other accessible tests are needed.

Objectives: To develop cardiac computed tomography to diagnose and quantify cardiac amyloidosis by measuring the myocardial Extracellular Volume, ECVCT.

Methods: Twenty-six patients (21 male, 64 ± 14 years) with a biopsy-proven systemic amyloidosis (ATTR n = 18; AL n = 8) were compared with twenty-seven patients (19 male, 68 ± 8 years) with severe aortic stenosis (AS). All patients had undergone echocardiography, bone scintigraphy, NT-pro-BNP measurement and EQ-CMR. Dynamic Equilibrium CT (DynEQ-CT) was performed using a prospectively gated cardiac scan prior to and after (5 and 15 minutes) a standard Iodixanol (1 ml/kg) bolus to measure ECVCT. ECVCT was compared to the reference ECVCMR and conventional amyloid measures: bone scintigraphy and clinical markers of cardiac amyloid severity (NT-pro-BNP, Troponin, LVEF, LV mass, LA and RA area).

Results: ECVCT and ECVCMR results were well correlated (r(2) = 0.85 vs r(2) = 0.74 for 5 and 15 minutes post bolus respectively). ECVCT was higher in amyloidosis than AS (0.54 ± 0.11 vs 0.28 ± 0.04, p<0.001) with no overlap. ECVCT tracked clinical markers of cardiac amyloid severity (NT-pro-BNP, Troponin, LVEF, LV mass, LA and RA area), and bone scintigraphy amyloid burden (p<0.001).

Conclusion: Dynamic Equilibrium CT, a 5 minute contrast-enhanced gated cardiac CT, has potential for non-invasive diagnosis and quantification of cardiac amyloidosis.

Keywords: Amyloidosis; CCT; CMR; Cardiac imaging techniques; Extracellular space.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Amyloidosis / blood
  • Amyloidosis / diagnostic imaging*
  • Biomarkers / blood
  • Biopsy
  • Bone and Bones / diagnostic imaging
  • Cardiac-Gated Imaging Techniques*
  • Cardiomyopathies / blood
  • Cardiomyopathies / diagnostic imaging*
  • Case-Control Studies
  • Contrast Media / administration & dosage
  • Electrocardiography
  • Extracellular Space / diagnostic imaging*
  • Female
  • Heart / diagnostic imaging*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Multidetector Computed Tomography*
  • Natriuretic Peptide, Brain / blood
  • Peptide Fragments / blood
  • Predictive Value of Tests
  • Radionuclide Imaging
  • Severity of Illness Index
  • Triiodobenzoic Acids / administration & dosage
  • Troponin / blood
  • Ultrasonography

Substances

  • Biomarkers
  • Contrast Media
  • Peptide Fragments
  • Triiodobenzoic Acids
  • Troponin
  • pro-brain natriuretic peptide (1-76)
  • Natriuretic Peptide, Brain
  • iodixanol