Detection and Characterization of Thrombosis in Humans Using Fibrin-Targeted Positron Emission Tomography and Magnetic Resonance.

Abstract

OBJECTIVES:

The authors present a novel technique to detect and characterize LAA thrombus in humans using combined positron emission tomography (PET)/cardiac magnetic resonance (CMR) of a fibrin-binding radiotracer, [64Cu]FBP8.

BACKGROUND:

The detection of thrombus in the left atrial appendage (LAA) is vital in the prevention of stroke and is currently performed using transesophageal echocardiography (TEE).

METHODS:

The metabolism and pharmacokinetics of [64Cu]FBP8 were studied in 8 healthy volunteers. Patients with atrial fibrillation and recent TEEs of the LAA (positive n = 12, negative n = 12) were injected with [64Cu]FBP8 and imaged with PET/CMR, including mapping the longitudinal magnetic relaxation time (T1) in the LAA.

RESULTS:

[64Cu]FBP8 was stable to metabolism and was rapidly eliminated. The maximum standardized uptake value (SUVMax) in the LAA was significantly higher in the TEE-positive than TEE-negative subjects (median of 4.0 [interquartile range (IQR): 3.0-6.0] vs 2.3 [IQR: 2.1-2.5]; P < 0.001), with an area under the receiver-operating characteristic curve of 0.97. An SUVMax threshold of 2.6 provided a sensitivity of 100% and specificity of 84%. The minimum T1 (T1Min) in the LAA was 970 ms (IQR: 780-1,080 ms) vs 1,380 ms (IQR: 1,120-1,620 ms) (TEE positive vs TEE negative; P < 0.05), with some overlap between the groups. Logistic regression using SUVMax and T1Min allowed all TEE-positive and TEE-negative subjects to be classified with 100% accuracy.

CONCLUSIONS:

PET/CMR of [64Cu]FBP8 is able to detect acute as well as older platelet-poor thrombi with excellent accuracy. Furthermore, the integrated PET/CMR approach provides useful information on the biological properties of thrombus such as fibrin and methemoglobin content. (Imaging of LAA Thrombosis; NCT03830320).

• Authors: David Izquierdo-Garcia, Pauline Désogère, Anne L Philip, Choukri Mekkaoui, Rory B Weiner, Onofrio A Catalano, Yin-Ching Iris Chen, Doreen DeFaria Yeh, Moussa Mansour, Ciprian Catana, Peter Caravan, David E Sosnovik
• Journal: JACC. Cardiovascular imaging (JACC Cardiovasc Imaging) Vol. 15 Issue 3 Pg. 504-515 (03 2022) ISSN: 1876-7591 [Electronic] United States
• PMID: 34656469 (Publication Type: Clinical Study, Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Chemical References

• Fibrin

Topics

• Atrial Appendage
• Fibrin
• Humans
• Magnetic Resonance Spectroscopy
• Positron-Emission Tomography
• Predictive Value of Tests
• Thrombosis (diagnostic imaging, pathology)
• Tomography, X-Ray Computed (methods)