RESUMEN
BACKGROUND: The myocardial kinetic energy (KE) and its association with pulmonary regurgitation (PR) have yet to be investigated in repaired tetralogy of Fallot (rTOF) patients. PURPOSE: To evaluate the adaptation of myocardial KE in rTOF patients by tissue phase mapping (TPM). STUDY TYPE: Prospective. POPULATION: A total of 49 rTOF patients (23 ± 5 years old; male = 32), 47 normal controls (22 ± 1 year old; male = 29). FIELD STRENGTH/SEQUENCE: 3-T/2D dark-blood three-directional velocity-encoded gradient-echo sequence. ASSESSMENT: Left and right ventricle (LV, RV) myocardial KE in radial (KEr ), circumferential (KEø ), longitudinal (KEz ) directions. The proportions of KE in each direction to the sum of all KE (KErøz ): %KEr , %KEø , %KEz . PR fraction. STATISTICAL TEST: Student's t test, multivariable regression. Statistical significance: P < 0.05. RESULTS: In rTOF group, LV KEz remained normal in systole (P = 0.565) and diastole (P = 0.210), whereas diastolic LV %KEz (62% ± 14% vs. 72% ± 7%) and systolic LV %KEø (9% ± 6% vs. 20% ± 7%) were significantly decreased. The KEr and %KEr of both ventricles significantly increased in the rTOF group (RV in diastole: 6 ± 3 vs. 3 ± 1 µJ and 54% ± 13% vs. 27% ± 7%). The rTOF group exhibited significantly higher RV/LV ratios of %KEr (systole: 1.3 ± 0.3 vs. 1.0 ± 0.3) and %KEø (systole: 1.6 ± 0.8 vs. 1.0 ± 0.3) and significantly lower ratios of %KEz in systole (0.7 ± 0.2 vs. 1.0 ± 0.1) and diastole (0.5 ± 0.2 vs. 0.9 ± 0.1). In multivariable regression analysis, the RV peak systolic KErøz , RV systolic KEz , and LV diastolic %KEø were independently associated with PR fraction in the rTOF group (adjusted R2 = 0.479). DATA CONCLUSION: In rTOF patients, the adaptation of the KE proportion occurred earlier than that of the KE amplitude, and the biventricular balance of %KE was disrupted. PR may cause differential KE adaptation in RV and LV. TPM-derived KE may be useful in investigation of myocardial adaptation in rTOF patients. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 3.
Asunto(s)
Insuficiencia de la Válvula Pulmonar , Tetralogía de Fallot , Humanos , Masculino , Adolescente , Adulto Joven , Adulto , Tetralogía de Fallot/cirugía , Estudios Prospectivos , Ventrículos Cardíacos , Miocardio , Función Ventricular DerechaRESUMEN
BACKGROUND: The myocardial adaptive mechanism in patients with repaired tetralogy of Fallot (rTOF) is less understood. We aimed to investigate biventricular myocardial adaptive remodeling in rTOF patients. METHODS: We recruited 32 rTOF patients and 38 age- and sex-matched normal controls. The pulmonary stenosis of rTOF patients was measured using catheterized pressure gradient between right ventricle (RV) and pulmonary artery (PGRVPA). rTOF patients with PGRVPA < 15 mmHg and ≥15 mmHg were classified as low pulmonary stenosis (rTOFlow, n = 19) and high pulmonary stenosis (rTOFhigh, n = 13) subgroups, respectively. Magnetic resonance imaging tissue phase mapping was employed to evaluate the voxelwise biventricular myocardial motion in longitudinal (Vz), radial (Vr), and circumferential (Vφ) directions. RESULTS: The rTOFlow subgroup presented higher pulmonary regurgitation fraction than rTOFhigh subgroup (p < 0.001). Compared with the normal group, only rTOFlow subgroup presented a decreased RV ejection fraction (RVEF) (p < 0.05). The rTOFlow subgroup showed decreased systolic and diastolic Vz in RV and LV, whereas rTOFhigh subgroup showed such change only in RV. In rTOFlow subgroup, RVEF significantly correlated with RV systolic Vr (r = 0.56, p < 0.05), whereas LVEF correlated with LV systolic Vz (r = 0.51, p = 0.02). Prolonged QRS correlated with RV systolic Vr (r = -0.58, p < 0.01) and LV diastolic Vr (r = 0.81, p < 0.001). No such correlations occurred in rTOFhigh subgroup. CONCLUSIONS: The avoidance of unfavorable functional interaction in RV and LV in rTOFhigh subgroup suggested that adequate pulmonary stenosis (PGRVPA ≥ 15 mmHg in this sereis) has a protective effect against pulmonary regurgitation.
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Imagen por Resonancia Magnética/métodos , Insuficiencia de la Válvula Pulmonar/diagnóstico por imagen , Estenosis de la Válvula Pulmonar/diagnóstico por imagen , Tetralogía de Fallot/diagnóstico por imagen , Tetralogía de Fallot/rehabilitación , Adulto , Presión Sanguínea , Estudios de Casos y Controles , Prueba de Esfuerzo , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Insuficiencia de la Válvula Pulmonar/fisiopatología , Estenosis de la Válvula Pulmonar/fisiopatología , Volumen Sistólico , Tetralogía de Fallot/fisiopatología , Tetralogía de Fallot/cirugía , Disfunción Ventricular Izquierda/fisiopatología , Disfunción Ventricular Derecha/fisiopatología , Función Ventricular Izquierda , Función Ventricular Derecha , Adulto JovenRESUMEN
OBJECTIVE: To investigate flow-related parameters in pulmonary arteries of patients with pulmonary arterial hypertension (PAH). MATERIALS AND METHODS: Eleven PAH patients and twelve control participants were recruited. PAH and controls had similar age and gender distribution. 2D phase-contrast MRI (PC-MRI) was performed in the main, right, and left pulmonary artery (MPA, RPA, and LPA). The flow velocity, wall shear stress (WSS), and oscillatory shear index (OSI) were measured. RESULTS: PAH patients displayed prolonged acceleration time (Tacce) and increased ratio of flow change to acceleration volume in pulmonary arteries (both P < 0.001). The temporally averaged WSS values of MPA, RPA, and LPA in PAH patients were significantly lower than those of control participants (P < 0.001). The OSI in the pulmonary arteries was higher in PAH patients than control participants (P < 0.05). The ROC analysis indicated the ratio of maximum flow change to acceleration volume, WSS, and Tacce exhibited sufficient sensitivity and specificity to detect patients with PAH. The WSS demonstrated strong correlations with Tacce and the ratio value in the two groups (R2 = 0.78-0.96). CONCLUSIONS: We used a clinically feasible 2D PC-MRI sequence with a reasonable scanning time to compute aforementioned indices. The quantitative parameters provided sufficient information to differentiate PAH patients from control participants.
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Hipertensión Pulmonar/diagnóstico por imagen , Imagen por Resonancia Magnética , Arteria Pulmonar/diagnóstico por imagen , Resistencia al Corte , Adulto , Femenino , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Oscilometría , Insuficiencia de la Válvula Pulmonar/diagnóstico por imagen , Curva ROC , Estrés Mecánico , Factores de TiempoRESUMEN
OBJECTIVES: We aimed to characterise regional myocardial motion and twist function in the left ventricles (LV) in patients with repaired tetralogy of Fallot (rTOF) and preserved LV global function. METHODS: We recruited 47 rTOF patients and 38 age-matched normal volunteers. Tissue phase mapping (TPM) was performed for evaluating the LV myocardial velocity in longitudinal, radial, and circumferential (Vz, Vr, and VØ) directions in basal, middle, and apical slices. The VØ peak-to-peak (PTP) during systolic phases, the rotation angle of each slice, and VØ inconsistency were computed for evaluating LV twist function and VØ dyssynchrony. RESULTS: As compared to the controls, the rTOF patients presented decreased RV ejection fraction (RVEF) (p = 0.002) and preserved global LV ejection fraction (LVEF). They also demonstrated decreased systolic and diastolic Vz in several LV segments and higher diastolic Vr in the septum (all p < 0.05). A lower VØ PTP, higher VØ inconsistency, and reduced peak net rotation angle (all p < 0.05) were observed. The aforementioned indices demonstrated an altered LV twist function in rTOF patients in an early disease stage. CONCLUSIONS: MR TPM could provide information about early abnormalities of LV regional motion and twist function in rTOF patients with preserved LV global function. KEY POINTS: ⢠Patients with rTOF presented significantly reduced systolic and diastolic Vz in the LV. ⢠rTOF patients demonstrated significantly increased diastolic Vr in the septum. ⢠Abnormal characteristics of the segmental dynamic velocity evolution were shown in rTOF. ⢠rTOF patients presented altered circumferential rotation and velocity inconsistency in early stage.