Multimodality Imaging in Cardiac Amyloidosis: Part 1 of 2—Evidence Base and Standardized Methods of Imaging

Publication Date: August 29, 2019
Last Updated: March 14, 2022

Key Recommendations

Diagnosis: Echocardiography

  • Comprehensive 2D echocardiography, including quantitative tissue Doppler and speckle-tracking strain analysis (when available) should be performed in all patients with unexplained LV wall thickening and a clinical suspicion of cardiac amyloidosis.  
  • To increase identification of this underdiagnosed disease, any echocardiographic abnormalities suggestive of cardiac amyloidosis should prompt further evaluation.  
  • Echocardiographic parameters should be combined with electrocardiographic, clinical, biomarker, and other imaging findings to maximize diagnostic accuracy.
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Diagnosis: Cardiac Magnetic Resonance

  • Comprehensive CMR-based evaluation of cardiac structure, function, and myocardial tissue characterization is helpful for diagnosis of cardiac amyloidosis, particularly when echocardiographic findings are suggestive or indeterminate.
  • In patients with biopsy-proven systemic amyloidosis, typical CMR findings, including diffuse LGE, nulling of myocardium before or at the same inversion time as the blood pool, and extensive ECV expansion are combined with structural findings of increased wall thickness and myocardial mass to diagnose cardiac involvement. In the absence of documented systemic amyloidosis, typical CMR features should prompt further evaluation for cardiac amyloidosis.
  • CMR, however, is typically unable to definitively distinguish AL from ATTR cardiac amyloidosis.
  • CMR parameters should be combined with electrocardiographic, clinical, biomarker, and other imaging findings to maximize diagnostic accuracy.
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Diagnosis: Radionuclide Imaging

  • Myocardial imaging with 99mTc-PYP/DPD/HMDP, in the appropriate clinical context, is highly sensitive and specific to diagnose ATTR cardiac amyloidosis and may aid in its early detection.  
  • In the absence of a light-chain clone, myocardial uptake of 99mTc-PYP/DPD/HMDP of Grade 2 is diagnostic of ATTR cardiac amyloidosis, obviating the need for endomyocardial biopsy.  
  • To facilitate early diagnosis of ATTR cardiac amyloidosis, cardiac 99mTc-PYP/DPD/HMDP scintigraphy should be more broadly considered in patients with unexplained increased LV wall thickness, heart failure with preserved ejection fraction, familial amyloid polyneuropathy, family history of amyloidosis, degenerative aortic stenosis with low-flow low gradient in the elderly, and a history of bilateral carpal tunnel syndrome.  
  • 123I-mIBG can detect cardiac denervation in patients with hereditary ATTR amyloidosis.
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Assessment of Prognosis

  • Multiple imaging parameters predict a worse prognosis, including increased LV mass, lower global longitudinal strain, increased right ventricular wall thickness, higher native T1 and ECV, higher H/CL ratio, and 123I-mIBG increased HMR and delayed washout rate.  
  • Although not formally incorporated into current riskassessment algorithms, radionuclide results should be combined with electrocardiographic, clinical, biomarker, and other imaging findings for optimal prognostication.
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Management

  • Transthoracic echocardiography is reasonable to monitor disease progression and/or response to therapy in cardiac amyloidosis because echocardiography is often done clinically for other reasons (ie, heart failure management).  
  • Transthoracic echocardiography (for the evaluation of left atrial size and function) and transesophageal echocardiography (for the evaluation of the left atrial appendage) are useful to guide initiation and management of anticoagulation in patients with cardiac amyloidosis.  
  • Cardiovascular magnetic resonance assessment of LV wall thickness, LV mass, and particularly ECV is emerging as a tool to assess disease progression and response to therapy.  
  • Serial SPECT 99mTc-PYP/DPD/HMDP scintigraphy is currently not recommended to assess disease progression or response to therapy.
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Standardized Imaging Techniques: Echocardiography

  • Echocardiograms in patients with suspected or known cardiac amyloidosis should be obtained using ASE/ EACVI guidelines on comprehensive echocardiography.  
  • Reporting should include assessment of wall thickness and myocardial “texture”; thickening of other cardiac structures; pericardial effusion; tissue Doppler velocities (s’, e’, and a’); diastolic function; and hemodynamics.
  •   STE should be performed routinely in patients with suspected or known cardiac amyloidosis when available, and efforts should be made to optimize the apical 2D imaging views for speckle-tracking analysis. The global longitudinal strain and pattern of segmental strains (ie, “bullseye” map) should be reported. RV and LA strain can be reported when performed.  
  • An overall reporting on likelihood of amyloidosis based on imaging findings is recommended (not suggestive, strongly suggestive, or equivocal for cardiac amyloidosis).
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Standardized Imaging Techniques: CMR

  • CMR should be performed using standard parameters, as listed in this section.  
  • Cardiac structure, function, and PSIR LGE should be assessed and reported per SCMR guidelines.  
  • Cardiac amyloidosis-specific CMR markers, such as native T1 mapping and ECV, should be assessed and reported when available, as discussed in this document.  
  • An overall reporting on likelihood of cardiac amyloidosis based on imaging findings is recommended (eg, not suggestive, strongly suggestive, or equivocal for cardiac amyloidosis).
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Standardized Image Techniques: Radionuclide Imaging

  • 99mTc-PYP/DPD/HMDP and 123I-mIBG imaging should be performed using standard protocols as discussed in this section.  
  • SPECT imaging is useful particularly in positive or equivocal cases to differentiate myocardial from blood pool signal and to describe regional heterogeneity.  
  • Visual and semiquantitative interpretation of 99mTc-PYP/ DPD/HMDP planar and SPECT images should be employed to evaluate heart-to-bone ratio and/or H/CL lung ratio. The HMR is used to interpret 123I-mIBG images.  
  • An overall reporting on likelihood of amyloidosis based on imaging findings is recommended (eg, not suggestive, strongly suggestive, or equivocal for cardiac amyloidosis and for extra-cardiac findings).
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Recommendation Grading

Overview

Title

Multimodality Imaging in Cardiac Amyloidosis: Part 1 of 2—Evidence Base and Standardized Methods of Imaging

Authoring Organization

Society of Nuclear Medicine and Molecular Imaging

Endorsing Organizations

American Heart Association

American Society of Echocardiography

American Society of Nuclear Cardiology

Heart Failure Society of America

Society of Nuclear Medicine and Molecular Imaging

Publication Month/Year

August 29, 2019

Last Updated Month/Year

January 12, 2023

Document Type

Consensus

External Publication Status

Published

Country of Publication

US

Inclusion Criteria

Female, Male, Adult, Older adult

Health Care Settings

Ambulatory, Hospital

Intended Users

Nurse, nurse practitioner, physician, physician assistant

Scope

Assessment and screening, Diagnosis

Diseases/Conditions (MeSH)

D006333 - Heart Failure, D054143 - Heart Failure, Systolic, D054144 - Heart Failure, Diastolic, D000682 - Amyloid, D002313 - Cardiomyopathy, Restrictive

Keywords

cardiac magnetic resonance (CMR), positron emission tomography (PET), amyloidosis, cardiac amyloidosis

Source Citation

  1. ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis: Part 1 of 2—Evidence Base and Standardized Methods of Imaging

    Dorbala, Sharmila et al.
    Journal of Cardiac Failure, Volume 25, Issue 11, e1 - e39