Background
Methods
CMR scan
Variables | Healthy subjects (n = 8) |
---|---|
Age (years) | 27 ± 3 |
Height (cm) | 176 ± 6 |
Weight (kg) | 80 ± 15 |
Body mass index (m2) | 25.5 ± 3.1 |
Gender ratio (male: female) | 5:3 |
Systolic blood pressure (mmHg) | 131 ± 16 |
Diastolic blood pressure (mmHg) | 80 ± 8 |
Heart rate (bpm) | 66 ± 8 |
Parameter | Unit | MRI1 | MRI2 |
---|---|---|---|
Field-of-view | mm3 | 290 × 290 × 56 | 312 × 384 × 50 |
Acquired spatial resolution | mm3 | 2.5 × 2.5 × 2.5 | 2.5 × 2.0 × 2.5 |
Reconstructed spatial resolution | mm3 | 2.0 × 2.0 × 2.0 | 2.0 × 2.0 × 2.0 |
Number of reconstructed heart phases | 24 | 24 | |
ECG synchronization | Retrospective | Retrospective | |
Respiratory motion compensation | Gating window 8 mm | Gating window 8 mm | |
Flip Angle | ° | 8 | 7 |
Parallel Imaging | SENSE acceleration factor: 2.2 | GRAPPA acceleration factor: 3.0 | |
Velocity-encoding factor | cm/s | 200 | 200 |
Processing of CMR data
Nomenclature of this publication | SW-A | SW-B | SW-C | SW-D |
---|---|---|---|---|
Stroke volume (ml) | Pumped blood volume (ml) | Total Volume (ml) | Stroke Volume (ml) | Flow (l) |
Forward stroke volume (ml) | Forward flow (ml) | Total Forward Volume (ml) | Net Forward Flow Volume (ml) | Forward (l) |
Backward stroke volume (ml) | Backward flow (ml) | Total Backward Volume (ml) | Net Backward Flow Volume (ml) | Backward (l) |
Peak flow (ml/s) | Flow Graph (ml/s) | Maximum Flow (ml/s) | peak value of time resolved “Net Flow” (ml/s) | peak value of time resolved “Flow” (l/s) |
Peak maximum velocity (cm/s) | Max Velocity Graph (cm/s) | peak value of time resolved “Max Mag” (cm/s) | peak value of time resolved “Velocity Max” (cm/s) | peak value of time resolved “Velocity Max” (m/s) |
Peak average velocity (cm/s) | Mean Velocity Graph (cm/s) | Maximum Mean Velocity (cm/s) | peak value of time resolved „Velocity Avg “ (cm/s) | peak value of time resolved “Velocity Mean” (m/s) |
Area (mm2) | Contour Area Graph (mm2) | Area (mm2) | Area (mm2) | Area (mm2) |
Wall shear stress (WSS) | ||||
WSS (mPa) | WSS1,2 (mPa) | WSS1,2 (Pa) | WSS Magnitude1 (N/m2) | WSS No projection1,2,3 (Pa) |
Temporal resolution | Yes | Yes | Yes | Yes |
Spatial resolution | 1 contour with n (90) Vectors | 1 contour, no segments | 1 contour with n (8) segments | 1 contour with n (8) segments |
Peak WSS per segment | Calculated: 11 vectors got grouped together. Peak of those mean values | – | Peak value of time resolved, “Segment 1 WSS Mag.” to “Segment 8 WSS Mag.” | Peak value of segmentally resolved “Max WSS(mean) No Projection” |
Peak WSS per contour | Calculated: Mean value of all WSS vectors | “Max Wall Shear Stress” | Peak value of time resolved “Avg WSS Mag” | Calculated: Peak value of the calculated mean WSS No Projection value of segments 1–8 calculated separately for each time point |
Statistics
Results
Intrareader variability as measure of repeatability
SW-A | SW-B | SW-C | SW-D | |
---|---|---|---|---|
Stroke volume | ||||
Absolute error [ml] | 0 ± 6 | − 1 ± 18 | 2 ± 6 | 0 ± 12 |
Relative error [%] | 1 ± 7 | − 2 ± 26 | 3 ± 8 | 0 ± 16 |
ICC | 0.967*** | 0.648* | 0.964*** | 0.790** |
Peak flow | ||||
Absolute error [ml/s] | 4 ± 27 | − 3 ± 89 | 26 ± 92 | 5 ± 41 |
Relative error [%] | 1 ± 7 | − 1 ± 27 | 8 ± 27 | 1 ± 11 |
ICC | 0.969*** | 0.644* | 0.663* | 0.917*** |
Peak maximum velocity | ||||
Absolute error [cm/s] | − 1 ± 11 | − 1 ± 28 | 5 ± 26 | − 2 ± − 20 |
Relative error [%] | − 1 ± 8 | − 1 ± 21 | 4 ± 19 | − 1 ± 13 |
ICC | 0.883** | 0.219 | 0.348 | 0.746* |
Peak average velocity | ||||
Absolute error [cm/s] | − 1 ± 10 | − 2 ± 17 | 9 ± 10 | 3 ± 7 |
Relative error [%] | − 1 ± 14 | − 2 ± 21 | 12 ± 13 | 4 ± 8 |
ICC | 0.809** | 0.394 | 0.541* | 0.839** |
Area | ||||
Absolute error [mm2] | 15 ± 97 | 13 ± 190 | − 80 ± 143 | − 21 ± 87 |
Relative error [%] | 3 ± 15 | 2 ± 29 | − 12 ± 19 | − 4 ± 15 |
ICC | 0.919*** | 0.705* | 0.788** | 0.915*** |
Peak WSS per segment | ||||
Absolute error [mPa] | 8 ± 133 | – | 737 ± 847 | − 137 ± 614 |
Relative error [%] | 1 ± 9 | – | 44 ± 50 | − 5 ± 29 |
ICC | 0.921*** | – | 0.068 | 0.677* |
Peak WSS per contour | ||||
Absolute error [mPa] | 14 ± 121 | − 32 ± 54 | 567 ± 563 | − 12 ± 156 |
Relative error [%] | 2 ± 11 | − 7 ± 12 | 60 ± 56 | − 1 ± 22 |
ICC | 0.921*** | 0.944*** | 0.068 | 0.706* |
Interreader variability as measure of reproducibility
SW-A | SW-B | SW-C | SW-D | |
---|---|---|---|---|
Stroke volume | ||||
Absolute error [ml] | − 1 ± 9 | 0 ± 20 | 7 ± 12 | − 1 ± 12 |
Relative error [%] | − 1 ± 11 | 0 ± 28 | 9 ± 15 | − 2 ± 16 |
ICC | 0.920*** | 0.569* | 0.823** | 0.809** |
Peak flow | ||||
Absolute error [ml/s] | − 7 ± 38 | − 5 ± 100 | 37 ± 45 | 1 ± 45 |
Relative error [%] | − 2 ± 10 | 2 ± 32 | 11 ± 12 | 1 ± 16 |
ICC | 0.937*** | 0.565* | 0.862** | 0.907*** |
Peak maximum velocity | ||||
Absolute error [cm/s] | − 1 ± 16 | 14 ± 27 | 3 ± 28 | − 2 ± 19 |
Relative error [%] | − 1 ± 13 | 12 ± 23 | 2 ± 19 | − 1 ± 13 |
ICC | 0.705* | 0.274 | 0.359 | 0.730* |
Peak average velocity | ||||
Absolute error [cm/s] | 2 ± 14 | 1 ± 17 | − 6 ± 10 | 2 ± 10 |
Relative error [%] | 2 ± 22 | 1 ± 22 | − 7 ± 13 | 3 ± 12 |
ICC | 0.556* | 0.304 | 0.699* | 0.754** |
Area | ||||
Absolute error [mm2] | − 18 ± 156 | 15 ± 192 | 92 ± 146 | 82 ± 75 |
Relative error [%] | − 6 ± 22 | 0 ± 30 | 17 ± 22 | − 6 ± 19 |
ICC | 0.757** | 0.605* | 0.671* | 0.861** |
Peak WSS per segment | ||||
Absolute error [mPa] | 4 ± 190 | – | 599 ± 718 | 591 ± 755 |
Relative error [%] | 0 ± 14 | – | 32 ± 42 | 18 ± 37 |
ICC | 0.827** | – | 0.227 | 0.480 |
Peak WSS per contour | ||||
Absolute error [mPa] | 31 ± 160 | 50 ± 78 | 357 ± 513 | 118 ± 135 |
Relative error [%] | 3 ± 15 | 10 ± 18 | 29 ± 52 | − 3 ± 26 |
ICC | 0.857** | 0.832** | 0.221 | 0.573* |
Inter-software variability as measure of reproducibility
Stroke volumes
SW-A/B | SW-A/C | SW-A/D | SW-B/C | SW-B/D | SW-C/D | |
---|---|---|---|---|---|---|
Net stroke volume | ||||||
Absolute error [ml] | 7 ± 19 | 2 ± 6 | 5 ± 17 | 6 ± 20 | 0 ± 21 | 3 ± 17 |
Relative error [%] | 9 ± 26 | 3 ± 8 | 6 ± 21 | − 7 ± 27 | − 1 ± 28 | 3 ± 21 |
ICC | 0.591* | 0.959*** | 0.634* | 0.589* | 0.466 | 0.664* |
Peak flow | ||||||
Absolute error [ml/s] | 24 ± 92 | 5 ± 27 | 17 ± 25 | − 29 ± 92 | 4 ± 78 | 22 ± 25 |
Relative error [%] | 7 ± 26 | − 1 ± 7 | 5 ± 7 | − 8 ± 26 | 1 ± 23 | 6 ± 7 |
ICC | 0.631* | 0.971*** | 0.972*** | 0.645* | 0.718* | 0.971*** |
Peak maximum velocity | ||||||
Absolute error [cm/s] | − 5 ± 27 | − 13 ± 28 | − 5 ± 14 | − 10 ± 26 | 2 ± 28 | 8 ± 29 |
Relative error [%] | − 4 ± 21 | − 10 ± 20 | − 4 ± 10 | − 4 ± 19 | 1 ± 20 | 6 ± 20 |
ICC | 0.258 | 0.248 | 0.797** | 0.401 | 0.352 | 0.328 |
Peak average velocity | ||||||
Absolute error [cm/s] | − 8 ± 18 | − 6 ± 15 | − 8 ± 10 | 1 ± 17 | − 1 ± 17 | − 3 ± 11 |
Relative error [%] | − 12 ± 25 | − 9 ± 21 | − 13 ± 15 | 1 ± 21 | − 2 ± 22 | − 4 ± 14 |
ICC | 0.276 | 0.505* | 0.697* | 0.314 | 0.314 | 0.688* |
Area | ||||||
Absolute error [mm2] | 31 ± 174 | 21 ± 147 | 66 ± 84 | 1 ± 207 | 43 ± 160 | 48 ± 131 |
Relative error [%] | 5 ± 26 | 2 ± 22 | 12 ± 14 | − 1 ± 32 | 8 ± 27 | 10 ± 21 |
ICC | 0.745* | 0.805** | 0.898** | 0.614* | 0.740* | 0.807** |
Peak WSS per segment | ||||||
Absolute error [mPa] | – | 395 ± 760 | 212 ± 437 | – | – | 505 ± 789 |
Relative error [%] | – | − 17 ± 45 | 20 ± 31 | – | – | 32 ± 49 |
ICC | 0.168 | 0.371 | 0.104 | |||
Peak WSS per contour | ||||||
Absolute error [mPa] | 716 ± 195 | 64 ± 553 | 595 ± 244 | 696 ± 496 | − 105 ± 126 | 502 ± 463 |
Relative error [%] | 88 ± 16 | 14 ± 52 | 68 ± 22 | − 77 ± 46 | − 23 ± 26 | 50 ± 47 |
ICC | 0.134 | 0.192 | 0.103 | 0.085 | 0.542* | 0.092 |
Peak flow
Peak velocities
Area
Wall shear stress (WSS)
Equivalence test
Duration of evaluation
Inter-scanner variability as measure of reproducibility
Stroke volume | Forward stroke volume | Backward stroke volume | |
---|---|---|---|
Absolute error | 2 ± 12 ml | 2 ± 11 ml | − 1 ± 1 ml |
Relative error [%] | 0 ± 15 | 1 ± 13 | 38 ± 120 |
ICC | 0.862** | 0.874** | 0.337 |
Peak flow | Peak maximum velocity | Peak average velocity | |
---|---|---|---|
Absolute error | 22 ± 60 ml/s | 9 ± 21 cm/s | 7 ± 15 cm/s |
Relative error [%] | 3 ± 16 | 8 ± 17 | 11 ± 22 |
ICC | 0.832** | 0.474 | 0.491 |
Area | Peak WSS per segment | Peak WSS per contour | |
---|---|---|---|
Absolute error | − 49 ± 137 mm2 | 144 ± 239 mPa | 110 ± 179 mPa |
Relative error [%] | − 8 ± 20 | 11 ± 17 | 10 ± 16 |
ICC | 0.828** | 0.659* | 0.764** |