Citations

In conventional shear wave elastography materials are assumed to be linear, elastic, homogeneous, and isotropic. These assumptions are important to account for in certain tissues because they are not always appropriate. Many tissues such as skeletal muscle, the kidney, and the myocardium are anisotropic. Shear waves can be used to investigate the directionally dependent mechanical properties of anisotropic media. To study these tissues in a systematic way and to account for the effects of the anisotropic architecture, laboratory-based phantoms are desirable. We will report on several phantom-based approaches for studying shear wave anisotropy, assuming that these materials are transversely isotropic. Phantoms with embedded fibers were used to mimic anisotropic tissues. Homogeneous phantoms were compressed to induce transverse isotropy according to the acoustoelastic phenomenon, which is related to nonlinear behavior of the materials. The fractional anisotropy of these phantoms was quantified to compare with measurements made in soft tissues. In addition, soft tissues are also viscoelastic, and we have developed a method to model viscoelastic transversely isotropic materials with the finite element method (FEM). The viscoelastic property estimation from phantom experiments and FEM simulations will also be discussed.

AbstractWe developed and implemented a ‘CPOE-QT Alert’ system, that is, clinical decision support integrated in the computerized physician order entry system (CPOE), in 2011. The system identifies any attempts to order medications with risk of torsade de pointes (TdP) for patients with a history of significant QT prolongation (QTc ≥500 ms) and alerts the provider entering the order. We assessed its impact by comparing orders and subsequent medication administration before and after activation of the system. We found a significant decrease in the proportion of completed order per ordering attempt after system activation (94% (1293/1379) vs 77% (1888/2453), difference 16.8%; p<0.001). This resulted in a 13.9% reduction in the administration of those medications to patients. A significant decrease was observed across all provider types, educational levels, and specialties. The CPOE-QT Alert system successfully reduced exposure to QT-prolonging medications in high risk patients.

Marfan syndrome is the most common inherited disorder of connective tissue affecting multiple organ systems. Identification of the facial, ocular and skeletal features should prompt referral for aortic imaging since sudden death by aortic dissection and rupture remains a major cause of death in patients with unrecognized Marfan syndrome. Echocardiography is recommended as the initial imaging test, and once a dilated aortic root is identified magnetic resonance or computed tomography should be done to assess the entire aorta. Prophylactic aortic root replacement is safe and has been demonstrated to improve life expectancy in patients with Marfan syndrome. Medical therapy for Marfan syndrome includes the use of beta blockers in older children and adults with an enlarged aorta. Addition of angiotensin receptor antagonists has been shown to slow the progression of aortic root dilation compared to beta blockers alone. Lifelong and regular follow up in a center for specialized care is important for patients with Marfan syndrome. We present a case of a patient with clinical features of Marfan syndrome and discuss possible therapeutic interventions for her dilated aorta.

ObjectivesThis study evaluated the feasibility of real time three‐dimensional transesophageal echocardiography (RT3DTEE) in the diagnosis and localization of aortic valve perforation.MethodsAortic valve perforation was diagnosed in 12 patients by multiplane two‐dimensional transesophageal echocardiography (2DTEE). We studied the feasibility of RT3DTEE using en face view in detection and precise localization of the aortic valve perforation. The artifactual dropout on RT3D images of aortic valve can mimic perforation and lead to a false positive diagnosis. We defined a true perforation as the hole with thicker margin and its visibility in both systole and diastole. We combined the RT3D images from 10 subjects with relatively normal aortic valve without perforation (test group) with the 12 with perforation for a blind review by an experienced echocardiographer.ResultsThere were 14 perforations in 12 patients. The perforation was located in the left coronary cusp in 1, the noncoronary cusp in 7, and the right coronary cusp in 6 patients. In the subgroup of 9 patients with 11 perforations, all were confirmed at surgery. In test group the artifact mimicking perforation was frequently encountered (7/10 or 70%). However, they did not meet the criteria for true perforation except in 1 (1 false positive). All true perforations were correctly recognized.ConclusionsEn face imaging with RT3DTEE can be used to confirm aortic valve perforation and its spatial location. However, RT3D should be used as an extension to comprehensive 2DTEE and color flow imaging.

Background Myocardial strain imaging is a sensitive echocardiographic technique for identifying ventricular dysfunction. The aim of this study was to describe a reference range for right ventricular ( RV ) strain in subjects without cardiopulmonary disease and to report these values from a systematic review and meta‐analysis of the current literature. Methods Prospective online measurement of RV free wall longitudinal systolic strain using speckle tracking echocardiography ( STE ) was performed in 116 subjects with normal echocardiograms and without cardiopulmonary disease or risk factors. A systematic search of studies in EMBASE and Medline reporting RV strain values was performed through February 2014. Results The mean age was 48 ± 16 years and 58% were female. Mean RV strain was −26 ± 4%. Ten studies involving a total of 486 patients met our inclusion criteria. The mean age range was 43–57 years and 59% were female. All prior studies were performed with offline strain analysis, and 9 used a GE Healthcare strain analysis software system. The weighted estimate of RV free wall strain measured using tissue Doppler imaging (4 studies) was −27 ± 1% (95% confidence interval [ CI ] −30% to −25%) and with STE (8 studies, including the current study data) −27 ± 2% (95% CI −29% to −24%), respectively. Conclusions A reference range for RV strain in subjects without cardiopulmonary disease is presented. These data may help facilitate the routine clinical measurement of RV strain in patients referred for right heart echocardiography assessment.

ABSTRACTObjectives:In adults, vitamin D deficiency is common in patients with nonalcoholic fatty liver disease (NAFLD) and has been associated with the severity of histology. There are known differences between adult and pediatric NAFLD, with little data regarding the relation between vitamin D and pediatric NAFLD. The aim of the present study was to examine the relation between vitamin D levels and NAFLD in children.Methods:Clinical and histological data were used from children ages 2 to 18 years with biopsy‐proven NAFLD enrolled in the Nonalcoholic Steatohepatitis Clinical Research Network studies. 25(OH) vitamin D levels were measured from serum. Data examined included demographics, anthropometrics, laboratory markers, and liver histology. Data were analyzed using 3 categories of vitamin D level: deficient (≤20 ng/mL), insufficient (21–29 ng/mL), and sufficient (≥30 ng/mL).Results:A total of 102 children were studied. There was a high prevalence (80/102, 78%) of vitamin D deficiency or insufficiency; however, there were no significant associations between vitamin D level and the histological characteristics or severity of NAFLD. Significantly higher levels of triglycerides were found in those with vitamin D deficiency (P = 0.004), but there was no association with other features of the metabolic syndrome.Conclusions:There is a high prevalence of vitamin D deficiency and insufficiency in children with biopsy‐proven NAFLD; however, no association was found between vitamin D deficiency and the severity of disease on biopsies. This differs from adult NAFLD studies in which vitamin D deficiency correlates with histological severity, suggesting differences in the risk factors for or consequences of pediatric NAFLD.

Objective: To compare the safety and effectiveness of video-assisted thoracic surgery (VATS) versus conventional median sternotomy (open) in the repair of secundum atrial septal defect (ASD) or patent foramen ovale (PFO). Design: Among 415 consecutive patients undergoing open or VATS ASD/PFO closure between 1993 and October 2012, 153 patients were compared using 2:1 frequency matching (n = 102 open vs 51 VATS). Matching variables include age, gender, body surface area, past medical history of neurologic events, and need of patch closure. Median age was 43 years (3-71 years), and 67% were female. Results: There were no early deaths in either group. There were no conversions to open sternotomy. Although mean cross-clamp time (14.5 ± 7.6 vs 26.3 ± 13.2 minutes, P < .001) and bypass time (31.7 ± 13.8 vs 60.9 ± 20.9 minutes, P < .001) were longer in the VATS group, patients who underwent VATS had shorter postoperative ventilation time (7.5 ± 6.4 vs 4.4 ± 2.8 hours, P = .03) with 62.7% extubated in the operating room, along with shorter intensive care unit stay (26.7 ± 10.8 vs 19.1 ± 9.9 hours, P < .001) and hospital stay (5.2 ± 1.9 vs 3.5 ± 0.9 days, P < .001). At early follow-up (mean 1.5 years, maximum 4.2 years), there was no difference in need for reintervention. Of the 27 patients who underwent VATS ASD/PFO closure for a neurologic event, none had a recurrence. Conclusion: The use of VATS provides a safe, equally effective alternative to conventional sternotomy for ASD/PFO closure, using a less invasive approach.

AbstractPrognostic significance of histological anaplasia and BRAF V600E mutation were retrospectively evaluated in 74 patients with pleomorphic xanthoastrocytoma (PXA). Median age at diagnosis was 21.5 years (31 pediatric, 43 adult) and median follow‐up 7.6 years. Anaplasia (PXA‐AF), defined as mitotic index ≥ 5/10HPF and/or presence of necrosis, was present in 33 cases. BRAF V600E mutation was detected in 39 (of 60) cases by immunohistochemical and/or molecular analysis, all negative for IDH1 (R132H). Mitotic index ≥ 5/10HPF and necrosis were associated with decreased overall survival (OS; P = 0.0005 and P = 0.0002, respectively). In all cases except two, necrosis was associated with mitotic index ≥ 5/10HPF. Patients with BRAF V600E mutant tumors had significantly longer OS compared with those without BRAF V600E mutation (P = 0.02). PXA‐AF patients, regardless of age, had significantly shorter OS compared with those without (P = 0.0003). Recurrence‐free survival was significantly shorter for adult PXA‐AF patients (P = 0.047) only. Patients who either recurred or died ≤3 years from diagnosis were more likely to have had either PXA‐AF at first diagnosis (P = 0.008) or undergone a non‐gross total resection procedure (P = 0.004) as compared with patients who did not. This study provides further evidence that PXA‐AF behaves more aggressively than PXA and may qualify for WHO grade III “anaplastic” designation.