Detection of amyloid deposition in the hip and shoulder joints on CT scans as indicative of ATTR-type cardiac amyloidosis

Abstract

Background

Amyloid deposition manifests as thickening and calcification of the joints on computed tomography (CT) images.

Purpose

To investigate the diagnostic potential of thickening and calcification of the shoulder and hip joints for the detection of transthyretin amyloid cardiomyopathy (ATTR-CM).

Material and Methods

We included 19 patients who had been assessed using ^99mTc-pyrophosphate scintigraphy between January 2019 and December 2022 and diagnosed with ATTR-CM. The incidence of calcification and synovial thickening in the hip and shoulder joints of the patients and controls was evaluated. Two radiologists determined differences in joint calcification and thickness on CT images using Pearson chi-square tests and unpaired t-tests, respectively.

Results

Shoulder and hip joint thickness (both P < 0.01) and calcifications (P < 0.05) significantly differed between the groups. The area under the receiver operating characteristic curve (AUC) was 0.74 for the shoulder joint, and the cut-off Youden index was 16.1 mm, with a sensitivity and specificity of 63.2% and 78.9%, respectively. The AUC was 0.844 for the hip joint, with an optimal cutoff of 11.8 mm, with a sensitivity and specificity of 71.4% and 89.5%, respectively. Inter-observer agreement was substantial between the radiologists for detecting hip and/or shoulder joint calcification (κ = 0.712). The interclass correlation coefficients (2, 1) were 0.65 and 0.71 for measurements of shoulder and hip joint thickness, respectively.

Conclusion

Thickened and calcified shoulder and hip joints are more likely to be found in patients with clinically diagnosed ATTR-CM than those without.