title: Measurement of myocardial amyloid deposition in systemic amyloidosis: insights from cardiovascular magnetic resonance imaging.
abstract: BACKGROUND
  Cardiac involvement in systemic amyloidosis is caused by the extracellular deposition of misfolded proteins, mainly immunoglobulin light chains (AL) or transthyretin (ATTR), and may be detected by cardiovascular magnetic resonance (CMR). The aim of this study was to measure myocardial extracellular volume (ECV) in amyloid patients with a novel T1 mapping CMR technique and to determine the correlation between ECV and disease severity.
  
  
  METHODS
  Thirty-six patients with biopsy-proven systemic amyloidosis (mean age 70 ± 9 years, 31 men, 30 with AL and six with ATTR amyloidosis) and seven patients with possible amyloidosis (mean age 64 ± 10 years, six men) underwent comprehensive clinical and CMR assessment, with ECV estimation from pre- and postcontrast T1 mapping. Thirty healthy subjects (mean age 39 ± 17 years, 21 men) served as the control group.
  
  
  RESULTS
  Amyloid patients presented with left ventricular (LV) concentric hypertrophy with impaired biventricular systolic function. Cardiac ECV was higher in amyloid patients (definite amyloidosis, 0.43 ± 0.12; possible amyloidosis, 0.34 ± 0.11) than in control subjects (0.26 ± 0.04, P < 0.05); even in amyloid patients without late gadolinium enhancement (0.35 ± 0.10), ECV was significantly higher than in the control group (P < 0.01). A cut-off value of myocardial ECV >0.316, corresponding to the 95th percentile in normal subjects, showed a sensitivity of 79% and specificity of 97% for discriminating amyloid patients from control subjects (area under the curve of 0.884). Myocardial ECV was significantly correlated with LV ejection fraction (R(2)  = 0.16), LV mean wall thickness (R(2)  = 0.41), LV diastolic function (R(2)  = 0.21), right ventricular ejection fraction (R(2)  = 0.13), N-terminal fragment of the pro-brain natriuretic peptides (R(2)  = 0.23) and cardiac troponin (R(2)  = 0.33).
  
  
  CONCLUSIONS
  Myocardial ECV was increased in amyloid patients and correlated with disease severity. Thus, measurement of myocardial ECV represents a potential noninvasive index of amyloid burden for use in early diagnosis and disease monitoring.
authors.affiliation: Fondazione Toscana Gabriele Monasterio, Pisa, Italy; Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Barison
authors.forename: G D
authors.initials: GD
authors.lastname: Aquaro
authors.forename: N R
authors.initials: NR
authors.lastname: Pugliese
authors.forename: F
authors.initials: F
authors.lastname: Cappelli
authors.forename: S
authors.initials: S
authors.lastname: Chiappino
authors.forename: G
authors.initials: G
authors.lastname: Vergaro
authors.forename: G
authors.initials: G
authors.lastname: Mirizzi
authors.forename: G
authors.initials: G
authors.lastname: Todiere
authors.forename: C
authors.initials: C
authors.lastname: Passino
authors.forename: P G
authors.initials: PG
authors.lastname: Masci
authors.forename: F
authors.initials: F
authors.lastname: Perfetto
authors.forename: M
authors.initials: M
authors.lastname: Emdin
mesh_terms: D000368:Aged; D000682:Amyloid / Q000378:metabolism*; D000686:Amyloidosis / Q000378:metabolism*; D009202:Cardiomyopathies / Q000378:metabolism*; D016022:Case-Control Studies; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D018810:Magnetic Resonance Angiography; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D011446:Prospective Studies
chemical_list: D000682:Amyloid; D003287:Contrast Media; D005682:Gadolinium
keywords: amyloidosis; biomarker; cardiac hypertrophy; cardiology; radiology