Assessment of myocardial injuries in ischaemic and non-ischaemic cardiomyopathies using magnetic resonance T1-rho mapping

Figure 1. Myocardial T1ρ mapping framework. (A) Schematic of the 2D myocardial T1ρ mapping technique. T1ρ mapping is performed using a single-shot electrocardiogram-triggered balanced steady-state free-precession sequence. (B) Five single-shot T1ρ-weighted images are acquired at different spin lock times (TSL) along the T1ρ decay curve. A T1ρ map is generated inline using a model-based non-rigid motion-corrected reconstruction. The curves shown in (B) are from acquired data.

Figure 2. Regional variations of myocardial T1ρ values in controls. (A) Myocardial T1ρ variations on the basal, medial, and apical short-axis levels. (B) Myocardial T1ρ values according to gender. (C) Myocardial T1ρ values extracted from the 16 left ventricular segments of the American Heart Association model (D). The centre cross in each box denotes the mean, the centre line represents the median, and the lower and upper limits of each box represent the first and third quartiles, respectively. Outliers are displayed as individual dots.

Figure 3. Averaged T1ρ values in the injured and remote segments in the different patient groups and in controls. Myocardial T1ρ values in patients were significantly higher in injured regions than in remote regions and in controls. *P < 0.05 for comparison to controls. †P < 0.05 for comparison to remote regions.

Figure 4. 57-Year-old female patient with CMR findings consistent with Takotsubo cardiomyopathy. Myocardial T2 maps exhibit myocardial oedema at the medial and apical short-axis levels (T2 = 67 ms) with a clear T1ρ elevation at these locations (T1ρ = 71 ms) whereas LGE images show a lack of ischaemia and delayed hyper-enhancement.

Figure 5. Examples of T1ρ maps in one control and three patients with heart disease. (A) 21-Year-old male patient (control) with normal T2 (45 ms), T1ρ (44 ms), native T1 (1006 ms), and normal LGE. (B) 33-Year-old male patient with acute ischaemic cardiomyopathy reflected by basal anteroseptal hyper-enhancements on LGE with T2 (67 ms) and T1ρ (80 ms) elevations. (C) 59-Year-old male patient with non-ischaemic dilated cardiomyopathy with subepicardial inferobasal hyper-enhancement on LGE with a clear T1ρ elevation in the same segment (79 ms) and normal T2 on T2 mapping (48 ms). (D) 51-Year-old male patient with acute myocarditis. Arrowheads indicate regions with myocardial injury.