Aortic isthmus flow reversal in fetal coarctation of the aorta and the associated factors.

INTRODUCTION: The aim of this study was to investigate the presence of aortic isthmus flow reversal and its associated factors in fetuses with positive and false-positive coarctation of the aorta (CoA) compared with normal controls. MATERIAL AND METHODS: Pregnant women with fetuses suspected of CoA and normal control were enrolled, and these women experienced prenatal ultrasound scan and followed up for 6 months after birth to confirm the presence of CoA. All the ultrasound parameters were analyzed. RESULTS: A total of 134 pregnant women were enrolled, with 43 CoA-positive fetuses and 91 CoA false-positive fetuses, and 334 matched pregnant women were enrolled in the control group. Aortic isthmus flow reversal occurred in 28 (65.1%) fetuses in the CoA-positive group, significantly (p < 0.05) more than in the false-positive (37 or 40.7%) or control group (64 or 19.2%). Aortic isthmus flow reversal was mostly in the full systole (n = 17 or 60.7%) or late systole and early-middle diastole (n = 10 or 35.7%) in the CoA-positive fetuses (n = 27 or 96.4%), significantly (p < 0.001) different from that in the false-positive or control group. The aortic isthmus flow reversal peak systolic velocity (PSV), flow volume, and ratio of reversed flow/forward flow were significantly (p < 0.05) increased in the CoA-positive and false-positive groups than in the control group. The aortic isthmus flow reversal incidence was significantly (p < 0.05) correlated with the middle cerebral artery (MCA) PSV in the total three groups or in the false-positive group but was significantly (p < 0001) negatively correlated with the MCA resistance index (RI) in the CoA-positive group. The incidence of the aortic isthmus flow reversal was significantly (p < 0.05) positively correlated with the umbilical artery (UA) RI in the false-positive group and with the UA RI in the total three groups. Independently associated factors for aortic isthmus flow reversal were isthmic flow volume/CCO (combined cardiac output) in the CoA-positive group. CONCLUSIONS: Reversal of flow in the aortic isthmus is much more common in true-positive cases of CoA as compared to controls, and isthmic flow reversal in the full systolic phase only suggests presence of CoA. The aortic isthmic reversed flow volume accounts for over half of the isthmic forward flow volume in the CoA-positive fetuses than in the normal controls.

Ultrasound parameters of arteries and heart in normal fetuses.

BACKGROUND: Currently, no normal ultrasound data of the fetuses during the 20-40 gestation have been obtained for references of fetal growth and development. If such ultrasound data existed for prenatal diagnosis of possible diseases and abnormalities, neonates would be able to get timely treatment immediately after birth. This study was thus performed to obtain ultrasound parameters of normal fetuses during the 20-40 week gestation and the distribution of ultrasound parameters with the gestational age for references of detecting potential fetal diseases and abnormalities. METHODS: Normal fetuses without any abnormalities were enrolled, and the ultrasound parameters of the general biology, arteries, and aorta were measured and analyzed. RESULTS: 417 normal fetuses were enrolled. A significant (P < 0.05) negative correlation with the gestational age was detected in the peak systolic velocity/peak diastolic velocity (S/D), pulsatility index (PI) and resistance index (RI) of the umbilical artery (UA). A relatively stable relationship with the gestational age was detected in the fetal weight%, S/D, PI and RI of the middle cerebral artery (MCA), peak systolic velocity (PSV) and velocity time integral (VTI) of the intra-abdominal UA, fetal heart to chest ratio, mitral valve (MV)- and tricuspid valve (TV)-E/A peak flow velocity, aortic isthmic Z-score and displacement, distance between the brachiocephalic artery-left common carotid artery (BA-LCCA) and LCCA-left subclavian artery (LSA), Z-score of aorta, ascending aorta (AAO), pulmonary artery (PA), main pulmonary artery (MPA), and descending aorta (DAO). A significant (P < 0.05) positive correlation with the gestational age was detected in the fetal biological data, MCA PSV and VTI, free-UA PSV and VTI and cardio-thoracic ratio, cardiac parameters, ductus arteriosus (DA) and isthmus diameter, aortic parameters, PA and MPA diameter, MPA PSV and VTI, isthmus flow volume and velocity and PA flow volume, DA and BA parameters, and LCCA and LSA parameters (flow volume, PSV, and VTI). CONCLUSION: A certain correlation and distribution trend is detected in the ultrasound parameters of normal fetuses, and the ratios among different parameters remain relative stable. These findings can be used for determination of abnormal growth of the fetuses in prenatal ultrasound scan.

Multi-frequency therapeutic ultrasound: A review.

Focused ultrasound is a noninvasive, radiation-free and real-time therapeutic approach to treat deep-seated targets, which benefits numerous diseases otherwise requiring surgeries. Treatment efficiency is one of the key factors determining therapeutic outcomes, but improving it solely by increasing the total power can be limited by the performance of general ultrasound devices. To address this, multi-frequency therapeutic ultrasound, using additional ultrasound waves of different frequencies on top of the standard single-frequency wave, provides a promising method for treatment efficiency enhancement with limited power. Several applications and numerical works have demonstrated its superiority on treatment enhancement. This paper presents an overview of the mechanisms, implementations, applications and decisive parameters of the multi-frequency therapeutic ultrasound, which could help to pave the way for better understanding and further developing this technology in the future.

Gall bladder wall thickening as non-invasive screening parameter for esophageal varices - a comparative endoscopic - sonographic study.

BACKGROUND: The mortality due to hemorrhage of esophageal varices (EV) is still high. The predominant cause for EV is liver cirrhosis, which has a high prevalence in Western Europe. Therefore, non-invasive screening markers for the presence of EV are of interest. Here, we aim to investigate whether non-inflammatory gall bladder wall thickening (GBWT) may serve as predictor for the presence of EV in comparison and combination with other non-invasive clinical and laboratory parameters. METHODS: One hundred ninety four patients were retrospectively enrolled in the study. Abdominal ultrasound, upper endoscopy and blood tests were evaluated. GBWT, spleen size and the presence of ascites were evaluated by ultrasound. Platelet count and Child-Pugh-score were also recorded. The study population was categorized in two groups: 122 patients without esophageal varices (non EV) compared to 72 patients with EV were analyzed by uni-and multivariate analysis. RESULTS: In the EV group 46% showed a non-inflammatory GBWT of ≥4 mm, compared to 12% in the non-EV group (p < 0.01). GBWT was significantly higher in EV patients compared to the non-EV group (mean: 4.4 mm vs. 2.8 mm, p < 0.0001), and multivariate analysis confirmed GBWT as independent predictor for EV (p < 0.04). The platelets/GBWT ratio (cut-off > 46.2) had a sensitivity and specificity of 78 and 86%, PPV 76% and NPV of 87%, and ROC analysis calculated the AUC of 0.864 (CI 0.809-0.919). CONCLUSIONS: GBWT occurs significantly more often in patients with EV. However, because of the low sensitivity, combination with other non-invasive parameters such as platelet count is recommended.