Single-source dual energy CT to assess myocardial extracellular volume fraction in aortic stenosis before transcatheter aortic valve implantation (TAVI)

PurposeTo assess myocardial extracellular volume fraction (ECV) measurement provided by a single-source dual-energy computed tomography (SSDE-CT) acquisition added at the end of a routine CT examination before transcatether aortic valve implantation (TAVI) compared to cardiac magnetic resonance imaging (MRI).Materials and methodsTwenty-one patients (10 men, 11 women; mean age, 86 ± 4.9 years [SD]; age range: 71–92 years) with severe aortic stenosis underwent standard pre-TAVI CT with additional cardiac SSDE-CT acquisition 7 minutes after intravenous administration of iodinated contrast material and myocardial MRI including pre- and post-contrast T1-maps. Myocardial ECV and standard deviation (σECV) were calculated in the 16-segments model. ECV provided by SSDE-CT was compared to ECV provided by MRI, which served as the reference. Analyses were performed on a per-segment basis and on a per-patient involving the mean value of the 16-segments.ResultsECV was slightly overestimated by SSDE-CT (29.9 ± 4.6 [SD] %; range: 20.9%–48.3%) compared to MRI (29.1 ± 3.9 [SD] %; range: 22.0%–50.7%) (P < 0.0001) with a bias and limits of agreement of +2.3% (95%CI: −16.1%– + 20.6%) and +2.5% (95%CI: −2.1%– + 7.1%) for per-segment and per-patient-analyses, respectively. Good (r = 0.81 for per-segment-analysis) to excellent (r = 0.97 for per-patient-analysis) linear relationships (both P < 0.0001) were obtained. The σECV was significantly higher at SSDE-CT (P < 0.0001). Additional radiation dose from CT was 1.89 ± 0.38 (SD) mSv (range: 1.48–2.47 mSv).ConclusionA single additional SSDE-CT acquisition added at the end of a standard pre-TAVI CT protocol can provide ECV measurement with good to excellent linear relationship with MRI.     

A Rare Case of Late LAD Reimplantation after Arterial Switch Operation

Arterial switch operation (ASO) is a complex neonatal operation in which transfer of the coronary arteries origins is the key to success. Coronary events after a successful ASO are not uncommon. We describe a rare case of a child who underwent an ASO in the neonatal period with one coronary (LAD) described as atretic left in place. At age seven, he developed myocardial ischemia due to retrograde flow with a steal phenomenon from the LAD into the pulmonary artery. The patient underwent a late LAD reimplantation. This case underscores that even very small ostia should be translocated at the time of ASO.     

延迟脐带结扎对新生儿近远期影响的研究进展

新生儿娩出后通过脐带结扎与母体分离,临床上比较传统的做法是生后立即结扎脐带,但是随着对脐带结扎时间的深入研究,延迟脐带结扎的优势已经引起了人们的重视.该文围绕延迟脐带结扎分别对早产儿和足月儿的近远期影响这一课题进行探讨,发现延迟脐带结扎可以促进新生儿胎盘输血,使血容量增加,从而改善了新生儿的贫血状态,促进了循环与内环境的稳定,且未发现延迟脐带结扎对新生儿有不良影响.