Interleaved T(1) and T(2) relaxation time mapping for cardiac applications

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Medical Physics
• Radiology

Background:

• Accurate diagnosis of acute myocardial infarction (MI) using MRI relies on T(1)-weighted and T(2)-weighted imaging to identify necrosis and edema.
• Quantitative analysis through T(1) and T(2) mapping offers improved diagnostic capabilities.

Purpose of the Study:

• To develop and present a novel, single-scan method for simultaneous quantification of T(1) and T(2) relaxation times in the short-axis view of the heart.
• To enable quantitative diagnosis of acute MI by assessing myocardial tissue characteristics.

Main Methods:

• Implementation of an electrocardiograph (ECG)-triggered, navigator-gated, interleaved T(1) and T(2) mapping sequence.
• The sequence utilized a 2D steady-state free precession (SSFP) approach with inversion-recovery (IR) for T(1) and T(2)-preparation pulses for T(2) quantification.
• Validation performed on phantoms, healthy volunteers, and patients with acute MI.

Main Results:

• In vivo relaxation time measurements demonstrated good agreement with established literature values.
• The interleaved sequence successfully measured T(1) and T(2) relaxation times in the myocardium.
• Acquisition of data for T(1) and T(2) map calculation was achieved in a single scan without requiring image registration.

Conclusions:

• The developed interleaved sequence allows for simultaneous T(1) and T(2) mapping in a single MRI scan, streamlining the diagnostic process.
• This technique holds potential for differentiating acute from chronic MI by quantifying gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) concentration.
• The method can assess myocardial edema extent using T(2) maps, improving the comprehensive evaluation of MI.