title: CMR-based differentiation of AL and ATTR cardiac amyloidosis.
abstract: OBJECTIVE
  This study was devised to describe the different cardiac magnetic resonance (CMR) appearances in light chain amyloid (AL) and transthyretin-related amyloidosis (ATTR).
  
  
  BACKGROUND
  CMR is increasingly used to investigate patients with suspected amyloidosis. Global subendocardial late gadolinium enhancement (LGE) has been reported as typical of AL amyloidosis, whereas different patterns have been noted in ATTR amyloidosis.
  
  
  METHODS
  We performed de novo analyses on original DICOM magnetic resonance imaging in 46 patients with cardiac AL amyloidosis and 51 patients with ATTR type who had been referred to a specialist amyloidosis center between 2007 and 2012 after CMR. Histological examination was performed in all cases, with immunohistochemistry, to confirm systemic amyloidosis.
  
  
  RESULTS
  Patients' median age was 68 ± 10 years, and 74% were male. Left ventricular mass was markedly increased in ATTR amyloidosis (228 g [202 to 267 g]) compared with AL type (167 g [137 to 191 g]) (p < 0.001). LGE was detected in all but 1 cardiac amyloidosis patient (AL type) and was substantially more extensive in ATTR compared with AL amyloidosis. Ninety percent of ATTR patients demonstrated transmural LGE compared with 37% of AL patients (p < 0.001). Right ventricular LGE was apparent in all ATTR patients but in only 33 AL patients (72%) (p < 0.001). Despite these findings, survival was significantly better in cardiac ATTR amyloidosis compared with AL type. We derived an LGE scoring system (Query Amyloid Late Enhancement) that independently differentiated ATTR from AL amyloidosis and, when incorporated into a logistic regression model with age and wall thickness, detected ATTR type with 87% sensitivity and 96% specificity.
  
  
  CONCLUSIONS
  Transmural patterns of LGE distinguished ATTR from AL cardiac amyloidosis with high accuracy in this real-world analysis of CMR. Precise diagnosis of cardiac amyloidosis is crucial given the role of chemotherapy in AL type and with novel therapies for ATTR type currently in development.
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom; Cardiovascular Sciences, St. George's University of London, London, United Kingdom. Electronic address: jdungu@sgul.ac.uk.
authors.forename: Jason N
authors.initials: JN
authors.lastname: Dungu
authors.affiliation: Cardiovascular Sciences, St. George's University of London, London, United Kingdom.
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Valencia
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Pinney
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Simon D J
authors.initials: SD
authors.lastname: Gibbs
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Dorota
authors.initials: D
authors.lastname: Rowczenio
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Janet A
authors.initials: JA
authors.lastname: Gilbertson
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Lachmann
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Wechalekar
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Julian D
authors.initials: JD
authors.lastname: Gillmore
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Whelan
authors.affiliation: National Amyloidosis Centre, UCL Medical School, Royal Free Campus, London, United Kingdom.
authors.forename: Philip N
authors.initials: PN
authors.lastname: Hawkins
authors.affiliation: Cardiovascular Sciences, St. George's University of London, London, United Kingdom.
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: Anderson
mesh_terms: D000368:Aged; D028227:Amyloid Neuropathies, Familial; D000686:Amyloidosis / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D005682:Gadolinium; D006331:Heart Diseases / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012680:Sensitivity and Specificity
chemical_list: D005682:Gadolinium
keywords: amyloid; cardiomyopathy; magnetic resonance imaging