December 1, 2005Radiology108 citations
View Full PaperCorrected Tetralogy of Fallot: Delayed Enhancement in Right Ventricular Outflow Tract
Key Result
Delayed enhancement in the RVOT was associated with increased RVOT diameter (32 vs 22 mm, P<.01) and decreased right ventricular ejection fraction (43% vs 54%, P<.001).
Study Design
Type
Observational (n=24)
Multicenter
No
Structured PICO
Does delayed enhancement on MRI correlate with RVOT dilatation and right ventricular hemodynamics in patients with corrected tetralogy of Fallot?
P
Population
24 patients (mean age 25 years) with corrected tetralogy of Fallot evaluated retrospectively using delayed enhancement MR imaging.
E
Exposure
Delayed enhancement magnetic resonance (MR) imaging using 0.2 mmol/kg gadopentetate dimeglumine.
C
Comparator
Patients without delayed enhancement in the right ventricular outflow tract (RVOT).
O
Outcome
Presence of fibrosis (delayed enhancement), largest anterior-posterior diameter of the RVOT, right ventricular volumes, and right ventricular ejection fraction.surrogate
Delayed enhancement in the RVOT is common after tetralogy of Fallot correction and is associated with RVOT dilatation and adverse right ventricular hemodynamics.
Main Result
Absolute Event Rate: 32% vs 22%
p-value: p=<.01
Abstract
PURPOSE: To evaluate retrospectively the presence of fibrosis and largest diameter of the right ventricular outflow tract (RVOT) by using delayed enhancement magnetic resonance (MR) imaging in patients who had undergone initial correction for tetralogy of Fallot. MATERIALS AND METHODS: MR imaging was performed in 24 consecutive patients (16 male, eight female; mean age, 25 years; age range, 13-47 years) with corrected tetralogy of Fallot. The study protocol was approved by the local ethics committee, and informed consent was not required. Fifteen minutes after injection of 0.2 mmol/kg gadopentetate dimeglumine, an inversion-recovery turbo field-echo sequence was applied for detection of delayed enhancement. Right ventricular volumes, ejection fraction, and anterior-posterior diameter of the RVOT were calculated. Mann-Whitney nonparametric testing was used to compare measurements of ventricular volume, function, and anterior-posterior diameter of the RVOT in the presence or absence of delayed enhancement. Correlation was tested with Pearson coefficient. RESULTS: Delayed enhancement was seen in 17 patients in the RVOT. During initial surgery, transannular patching was performed in 13 (76%) of 17 patients, RVOT patching in one (6%) of 17 patients, and the Brock procedure in two (12%) of 17 patients. In one patient, the type of initial RVOT repair was unknown. Patients with delayed enhancement in the RVOT, as compared with those without delayed enhancement in the RVOT, had increased RVOT diameter (32 mm +/- 7 standard deviation vs 22 mm +/- 3, P < .01), decreased right ventricular ejection fraction (43% +/- 6.3 vs 54% +/- 10, P < .001), and increased end-diastolic volume (175 mL/m2 +/- 42 vs 118 mL/m2 +/- 34, P < .01). The diameter of the RVOT correlated with increased right ventricular end-systolic volume (R = 0.86) and was inversely related to ejection fraction (R = -0.65). CONCLUSION: Delayed enhancement occurs frequently in patients after correction for tetralogy of Fallot. Delayed enhancement in the RVOT was associated with RVOT dilatation, which adversely affects right ventricular hemodynamics.