Background
Methods
Study population
BCPC | Fontan |
p value
| |
---|---|---|---|
Age at CMR (years) | 2.9 ± 1.3 | 14.4 ± 5.9 | 0.01* |
Weight (kg) | 12.5 ± 3.1 | 46.2 ± 22 | 0.01* |
BSA (m2) | 0.5 ± 0.1 | 1.4 ± 0.4 | 0.01* |
Females (%) | 8 (57 %) | 4 (27 %) | >0.05 |
Age at BCPC (years) | 0.6 ± 0.2 | 1.1 ± 0.8 | 0.01* |
Time between BCPC – CMR (years) | 2.3 ± 1.3 | 11.4 ± 3.1 | 0.01* |
Age at Fontan (years) | - | 5.7 ± 6.5 | - |
Time between BCPC-Fontan (years) | - | 2.9 ± 1.3 | - |
Time between Fontan – CMR (years) | - | 8.6 ± 4.1 | - |
Primary cardiac diagnosis
| |||
Double inlet left ventricle | 1 | 4 | n/a |
Tricuspid atresia | 1 | 3 | n/a |
PA – IVS | 2 | - | n/a |
HLHS | 10 | 5 | n/a |
Unbalanced AVSD | 1 | 2 | n/a |
Straddling AV valve | - | 1 | n/a |
Staged palliated surgery
| |||
Hemi-Fontan | 11 | - | n/a |
BCPC | 3 | - | n/a |
Classic Fontan (Atriopulmonary connection) | - | 4 | n/a |
Intracardiac Lateral tunnel | - | 2 | n/a |
Extracardiac Conduit | - | 9 | n/a |
CMR studies
Two-dimensional phase-contrast flow
2D velocity acquisition | 4D velocity acquisition | |
---|---|---|
Field of view (mm) | 150 x 300 | 200 x 300 |
Acquired voxel size (mm) | 2.3 x 2.3 x 7 | 2.4 x 2.5 x 2.5 |
Reconstructed voxel size (mm) | 1.2 x 1.2 x 7 | 1.5 x 1.5 x 2.3 |
Number of slices | 1 | 25-40 |
Cardiac gating | Retrospective | Retrospective |
Respiratory motion | Non-gated | Non-gated |
Free breathing | Free breathing | |
NSA | 2 | 1 |
TR(ms)/TE(ms) | 5/3 | 3.2 /1.9 |
Flip angle (°) | 10 | 5 |
SENSE | No | 2 |
Reconstructed cardiac phases | 35-40 | 22-25 |
VEC (cm/s) | 60-100 (venous vessels) 200–400 (arterial vessels) | 150-400 |
Four-dimensional velocity acquisition
Flow data post-processing
Statistical analysis and calculations
Validation of 4D versus 2D velocity acquisition
Evaluation of SPCF
Derived equations | |
---|---|
Systemic blood flow (Q
S
)
| |
Traditional (Systemic arterial supply) | AO |
New (Systemic venous return) | SVC + IVC |
Pulmonary blood flow (Q
P
)
| |
Traditional (Pulmonary arterial supply) | RPA + LPA |
New (Pulmonary venous return) | RPV + LPV |
Systemic-to-pulmonary collateral flow (SPCF)
| |
Systemic flow estimator | (AO) – (SVC + IVC) |
Pulmonary flow estimator | (RPV + LPV) - (RPA + LPA) |
Pulmonary right to left flow distribution
Systemic lower to upper body flow distribution
Results
Baseline characteristics
Validation of 4D velocity acquisition versus 2D flow measurements in patients
BCPC | Fontan | Univentricular heart physiology | ||||
---|---|---|---|---|---|---|
2D velocity acquisition
|
4D velocity acquisition
|
2D velocity acquisition
|
4D velocity acquisition
|
Bland-Altman
|
Pearson
| |
difference
|
Correlation
| |||||
2D - 4D velocity acquisition
|
2D - 4D velocity acquisition
| |||||
SVC
| 1.77±0.61 | 1.62±0.61 | 0.93±0.34 | 0.92±0.35 | 0.07 ± 0.04 | 0.96 * |
IVC
| 1.79±1.01 | 1.74±1.05 | 1.80±0.63 | 1.64±0.55 | 0.11 ± 0.01 | 0.93 * |
RPA
| 1.06±0.37 | 1.01±0.36 | 1.43±0.51 | 1.47±0.59 | 0.01 ± 0.05 | 0.91* |
LPA
| 0.79±0.37 | 0.77±0.44 | 1.12±0.28 | 1.10±0.33 | 0.02 ± 0.05 | 0.94* |
AO
| 3.61±1.21 | 3.57±1.16 | 3.08±0.70 | 3.04±0.56 | 0.04 ± 0.05 | 0.94* |
SPCF
| 0.59±0.52 | 0.79±0.45 | 0.41±0.46 | 0.62±0.82 | −0.02 ± 0.18 | 0.73* |
Qp:Qs
| (0.43±0.23):1 | (0.42±0.23):1 | (0.82±0.29):1 | (0.84±0.26):1 | (0.02 ± 0.18):1 | 0.82* |
4D velocity acquisition for SPCF: patients versus controls
Demographics | |
---|---|
Controls (n) | 20 |
Age at CMR (years) | 28.7±13.1 |
Weight (kg) | 65.9±19.2 |
BSA (m2) | 1.7±0.4 |
Females (%) | 9 (41 %) |
4D velocity acquisition (l/min/m
2
) | |
SVC | 0.91±0.14 |
IVC | 1.8±0.43 |
RPA | 1.48 ± 0.28 |
LPA | 1.26 ± 0.25 |
RPV | 1.45 ± 0.29 |
LPV | 1.28 ± 0.25 |
AO | 2.74±0.45 |
SPCF | −0.01±0.16 |