# Reduced Native T1 Values of Wrist Tissues in Transthyretin Cardiac Amyloidosis

## TL;DR

ATTR-CA patients have lower T1 values in wrist tissues, suggesting early amyloid detection via MRI could be possible.

## Contribution

This study identifies reduced native T1 values in wrist tissues as a potential non-invasive marker for peripheral amyloid involvement in ATTR-CA.

## Key findings

- ATTR-CA patients showed significantly lower T1 values in multiple wrist tissues compared to healthy volunteers.
- SFCT T1 mapping had the highest AUC for detecting cardiac amyloidosis.
- Symptomatic CTS patients had lower SCF T1 values than asymptomatic ones.

## Abstract

Background/Objectives: Carpal tunnel syndrome (CTS) may signal extracardiac amyloid deposition years before transthyretin cardiac amyloidosis (ATTR-CA). This study investigated potential alterations of wrist tissue T1 values in ATTR-CA patients. Methods: Patients with ATTR-CA and healthy volunteers underwent 1.5T wrist MRI using a gradient echo sequence. Manual contouring of the transverse carpal ligament (TCL), median nerve (MN), sheaths of the flexor carpi tendons (SFCT), subcutaneous fat (SCF), muscle of the thenar eminence (MTE), and global wrist (GCW) was performed by two readers. Native T1 values were compared between groups. Results: Thirty-six patients with ATTR-CA (mean age, 78 ± 9 years; 32 men) and 69 volunteers (43 ± 14 years; 24 men) were evaluated. Mean native T1 values of TCL, MN, SFCT, SCF, and GCW were significantly lower in patients than in volunteers (p < 0.005 for all). Multivariable regression adjusted for age and sex confirmed these associations. SCF T1 was significantly lower in patients with CTS symptoms (885 [762–1080] ms) than in asymptomatic patients (1041 [949–1267] ms, p = 0.04). The highest area under the curve (AUC) for detecting CA was obtained for SFCT (AUC = 0.85; 95% CI 0.77–0.93). Conclusions: Patients with transthyretin cardiac amyloidosis show a significant reduction in the native T1 of wrist tissues compared with controls. These preliminary findings suggest that wrist T1 mapping may serve as a non-invasive marker of peripheral amyloid involvement, but require further validation in larger, age-matched, histologically validated studies.