Background: Left-to-right (L-R) shunts are characterized by a pathological connection between high- and low-pressure systems, leading to a mixing of oxygen-rich blood with low oxygenated blood. They are typically diagnosed by phase-contrast cardiac magnetic resonance imaging (MRI) which requires extensive planning. T2 is sensitive to blood oxygenation and may be able to detect oxygenation differences between the left (LV) and right ventricles (RV) caused by L-R shunts.
Purpose: To test the feasibility of routine T2 mapping to detect L-R shunts.
Study Type: Retrospective.
Population: Patients with known L-R shunts (N = 27), patients with RV disease without L-R shunts (N = 21), and healthy volunteers (HV; N = 52).
Field Strength/sequence: 1.5 and 3 T/balanced steady-state free-precession (bSSFP) sequence (cine imaging), T2-prepared bSSFP sequence (T2 mapping), and velocity sensitized gradient echo sequence (phase-contrast MRI).
Assessment: Aortic (Qs) and pulmonary (Qp) flow was measured by phase-contrast imaging, and the Qp/Qs ratio was calculated as a measure of shunt severity. T2 maps were used to measure T2 in the RV and LV and the RV/LV T2 ratio was calculated. Cine imaging was used to calculate RV end-diastolic volume index (RV-EDVi).
Statistical Tests: Wilcoxon test, paired t-tests, Spearmen correlation coefficient, receiver operating curve (ROC) analysis. Significance level P < 0.05.
Results: The Qp/Qs and T2 ratios in L-R shunt patients (1.84 ± 0.84 and 0.89 ± 0.07) were significantly higher compared to those in patients with RV disease (1.01 ± 0.03 and 0.72 ± 0.10) and in HV (1.04 ± 0.04 and 0.71 ± 0.09). A T2 ratio of >0.78 showed a sensitivity, specificity, and negative predictive value of 100%, 73.9%, and 100%, respectively, for the detection of L-R shunts. The T2 ratio was strongly correlated with the severity of the shunt (r = 0.83).
Data Conclusion: RV/LV T2 ratio is an imaging biomarker that may be able to detect or rule-out L-R shunts. Such a diagnostic tool may prevent unnecessary phase-contrast acquisitions in cases with RV dilatation of unknown etiology.
Level Of Evidence: 3 TECHNICAL EFFICACY: Stage 2.
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http://dx.doi.org/10.1002/jmri.27881 | DOI Listing |
J Physiol
January 2025
Heart Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.
Although the corticosteroid betamethasone is routinely administered to accelerate lung and cardiovascular maturation in the preterm fetus prior to birth, and use of delayed cord clamping (DCC) is recommended at birth by professional bodies, it is unknown whether antenatal betamethasone alters perinatal pulmonary or systemic arterial blood flow accompaniments of DCC. To address this issue, preterm fetal lambs [gestation 127 (1) days, term = 147 days] with (n = 10) or without (n = 10) antenatal betamethasone treatment were acutely instrumented under general anaesthesia with flow probes to obtain left (LV) and right ventricular (RV) outputs, major central arterial blood flows and shunt flow across both the ductus arteriosus and foramen ovale (FO). After delivery, lambs underwent initial ventilation for 2 min prior to DCC.
View Article and Find Full Text PDFInt J Cardiol Congenit Heart Dis
September 2024
Royal Brompton Hospital, Part of Guys St Thomas NHS Trust, and National Heart and Lung Institute, Imperial College London, London, United Kingdom.
Pulmonary arterial hypertension (PAH) is defined as increase in mean pulmonary arterial pressure and pulmonary vascular resistance (PVR). It can be associated with congenital heart disease (CHD) with the following subtypes: 1) uncorrected left-to-right (L-R) intracardiac shunt leading to overload of the pulmonary circulation and a progressive increase of PVR; 2) Eisenmenger syndrome, appearing when a large post-tricuspid shunt is left uncorrected and pulmonary vascular disease (PVD) is severe, so the shunt becomes bidirectional or right-to-left, causing cyanosis; 3) PAH after shunt closure, when PVR arises after a defect correction; and 4) PAH associated with small or coincidental defects. While the treatment of patients with Eisenmenger syndrome is well established, the treatment of patients with PAH in whom there is a L-R shunt (with no cyanosis) remains unclear and requires expertise.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Rd., Bangkok, 10700, Thailand.
Pulmonary arterial hypertension (PAH) associated with congenital heart disease (PAH-CHD) is a consequence of unrepaired large systemic-to-pulmonary shunts. The long-term data of adult patients who have PAH-CHD with elevated pulmonary vascular resistance (PVR) are limited. We aimed to investigate the survival of adults who had PAH-CHD with predominantly left-to-right (L-R) shunts with (1) borderline-to-high PVR and (2) treat-and-repair compared with those with Eisenmenger syndrome (ES).
View Article and Find Full Text PDFAm J Ophthalmol
November 2024
From the Department of Ophthalmology (A.F., D.M.V., K.A., I.Y.C., D.S.F., A.L., A.C.L., J.W.M., P.P., K.S., T.E., N.Z., J.W.M., A.L.), Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA. Electronic address:
Blood Purif
January 2025
Renal Research Institute, New York, New York, USA.
Introduction: Arteriovenous fistula (AVF) maturation assessment is essential to reduce venous catheter residence. We introduced central venous oxygen saturation (ScvO2) and estimated upper body blood flow (eUBBF) to monitor newly created fistula maturation and recorded catheter time in patients with and without ScvO2-based fistula maturation.
Methods: From 2017 to 2019, we conducted a multicenter quality improvement project (QIP) in hemodialysis patients with the explicit goal to shorten catheter residence time post-AVF creation through ScvO2-based maturation monitoring.
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