Original Research
Deep Learning on Bone Scintigraphy to Detect Abnormal Cardiac Uptake at Risk of Cardiac Amyloidosis

https://doi.org/10.1016/j.jcmg.2023.01.014Get rights and content
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Abstract

Background

Cardiac uptake on technetium-99m whole-body scintigraphy (WBS) is almost pathognomonic of transthyretin cardiac amyloidosis. The rare false positives are often related to light-chain cardiac amyloidosis. However, this scintigraphic feature remains largely unknown, leading to misdiagnosis despite characteristic images. A retrospective review of all WBSs in a hospital database to detect those with cardiac uptake may allow the identification of undiagnosed patients.

Objectives

The authors sought to develop and validate a deep learning–based model that automatically detects significant cardiac uptake (Perugini grade ≥2) on WBS from large hospital databases in order to retrieve patients at risk of cardiac amyloidosis.

Methods

The model is based on a convolutional neural network with image-level labels. The performance evaluation was performed with C-statistics using a 5-fold cross-validation scheme stratified so that the proportion of positive and negative WBSs remained constant across folds and using an external validation data set.

Results

The training data set consisted of 3,048 images: 281 positives (Perugini grade ≥2) and 2,767 negatives. The external validation data set consisted of 1,633 images: 102 positives and 1,531 negatives. The performance of the 5-fold cross-validation and external validation was as follows: 98.9% (± 1.0) and 96.1% for sensitivity, 99.5% (± 0.4) and 99.5% for specificity, and 0.999 (SD = 0.000) and 0.999 for the area under the curve of the receiver-operating characteristic curves. Sex, age <90 years, body mass index, injection-acquisition delay, radionuclides, and the indication of WBS only slightly affected performances.

Conclusions

The authors’ detection model is effective at identifying patients with cardiac uptake Perugini grade ≥2 on WBS and may help in the diagnosis of patients with cardiac amyloidosis.

Key Words

amyloidosis
bone scintigraphy
machine learning

Abbreviations and Acronyms

2D
2-dimensional
AL-CA
light-chain cardiac amyloidosis
CA
cardiac amyloidosis
CNN
convolutional neural network
DPD
3,3-diphosphono-1,2-propanodicarboxylic acid
HMDP
hydroxymethylene diphosphonate
ROC
receiver-operating characteristic
SPECT
single-photon emission computed tomography
99mTc
technetium-99m
TTR-CA
transthyretin cardiac amyloidosis
WBS
whole-body scintigraphy

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The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.

Dr El Esper died on October 6, 2021.