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Table 1 Comparison of FAST+CSPAMM versus FAST+SPAMM for mean peak twist, torsion, systolic twisting rate, diastolic untwisting rate, normalized untwist rate, time to peak systolic twist, and duration of untwist.

From: Quantitative assessment of systolic and diastolic left ventricular twist using Fourier Analysis of STimulated echoes (FAST) and CSPAMM

 

FAST+CSPAMM

FAST+SPAMM

Bland-Altman

Linear Regression

 

Mean Peak Value

Mean Peak Value

Bias, [95%CI]

CSPAMM=m*SPAMM, r

Twist [deg]

12.7±3.0

12.0±3.3

0.2, [-5.6,6.0]

CS= 0.98*SP, r=0.8

Torsion [deg/cm]

3.2±0.9

3.0±0.8

0.08, [-1.3,1.4]

CS= 0.99*SP, r=0.83

Systolic Twisting Rate [deg/s]

81.8±38.2

69.9±20.7

-0.6, [-67.3,66.2]

CS= 0.90*SP, r=0.84

Diastolic Untwisting Rate [deg/s]

-102.7±24.6

-106.7±32.4

  

Normalized Untwist Rate [1/s]

-8.4±2.4

-9.3±2.6

  

Time to Peak Systolic Twist [ms]

278.5±22.9

293.0±24.9

  

Duration of Untwisting [ms]

147.9±21.0

   
  1. Peak twist was defined as the maximum twist value for each subject. LV torsion was calculated as LV twist divided by the distance between the apical and basal slices with units of deg/cm. Peak torsion was defined as the maximum torsion value for each subject. Twist rate was calculated as the discrete derivative of twist with respect to time with units of deg/s. Peak twist rate was defined as the maximum twist rate. Peak diastolic untwist rate was defined as the minimum twist rate. Normalized peak untwist rate was defined as the minimum twist rate divided by the maximum twist angle with units of s-1. Time to peak twist was defined as the time [ms] from the first image frame (t=0 ms) until the frame of peak twist. To determine the duration of untwisting the data was normalized and interpolated. Cubic smoothing spline interpolation to 1% increments of the cardiac cycle was performed. This step was done to reduce noise and better detect the end of untwisting, which was determined by finding the maximum of the second derivative of the twist data after peak systolic twist.