Concept: Medical ultrasonography
Background Zika virus (ZIKV) has been linked to neonatal microcephaly. To characterize the spectrum of ZIKV disease in pregnancy, we followed patients in Rio de Janeiro to describe clinical manifestations in mothers and repercussions of acute ZIKV infection in fetuses. Methods We enrolled pregnant women in whom a rash had developed within the previous 5 days and tested blood and urine specimens for ZIKV by reverse-transcriptase-polymerase-chain-reaction assays. We followed the women prospectively and collected clinical and ultrasonographic data. Results A total of 88 women were enrolled from September 2015 through February 2016; of these 88 women, 72 (82%) tested positive for ZIKV in blood, urine, or both. The timing of acute ZIKV infection ranged from 5 to 38 weeks of gestation. Predominant clinical features included pruritic descending macular or maculopapular rash, arthralgias, conjunctival injection, and headache; 28% had fever (short-term and low-grade). Women who were positive for ZIKV were more likely than those who were negative for the virus to have maculopapular rash (44% vs. 12%, P=0.02), conjunctival involvement (58% vs. 13%, P=0.002), and lymphadenopathy (40% vs. 7%, P=0.02). Fetal ultrasonography was performed in 42 ZIKV-positive women (58%) and in all ZIKV-negative women. Fetal abnormalities were detected by Doppler ultrasonography in 12 of the 42 ZIKV-positive women (29%) and in none of the 16 ZIKV-negative women. Adverse findings included fetal deaths at 36 and 38 weeks of gestation (2 fetuses), in utero growth restriction with or without microcephaly (5 fetuses), ventricular calcifications or other central nervous system (CNS) lesions (7 fetuses), and abnormal amniotic fluid volume or cerebral or umbilical artery flow (7 fetuses). To date, 8 of the 42 women in whom fetal ultrasonography was performed have delivered their babies, and the ultrasonographic findings have been confirmed. Conclusions Despite mild clinical symptoms, ZIKV infection during pregnancy appears to be associated with grave outcomes, including fetal death, placental insufficiency, fetal growth restriction, and CNS injury.
This paper tackles the design of a graphical user interface (GUI) based on Matlab (MathWorks Inc., MA), a worldwide standard in the processing of biosignals, which allows the acquisition of muscular force signals and images from a ultrasound scanner simultaneously. Thus, it is possible to unify two key magnitudes for analyzing the evolution of muscular injuries: the force exerted by the muscle and section/length of the muscle when such force is exerted. This paper describes the modules developed to finally show its applicability with a case study to analyze the functioning capacity of the shoulder rotator cuff.
Discrimination between simple and perforated appendicitis in patients with suspected appendicitis may help to determine the therapy, timing of surgery and risk of complications. The aim of this study was to estimate the accuracy of magnetic resonance imaging (MRI) in distinguishing between simple and perforated appendicitis, and to compare MRI against ultrasound imaging with selected additional (conditional) use of computed tomography (CT).
Controlling acoustic fields is crucial in diverse applications such as loudspeaker design, ultrasound imaging and therapy or acoustic particle manipulation. The current approaches use fixed lenses or expensive phased arrays. Here, using a process of analogue-to-digital conversion and wavelet decomposition, we develop the notion of quantal meta-surfaces. The quanta here are small, pre-manufactured three-dimensional units-which we call metamaterial bricks-each encoding a specific phase delay. These bricks can be assembled into meta-surfaces to generate any diffraction-limited acoustic field. We apply this methodology to show experimental examples of acoustic focusing, steering and, after stacking single meta-surfaces into layers, the more complex field of an acoustic tractor beam. We demonstrate experimentally single-sided air-borne acoustic levitation using meta-layers at various bit-rates: from a 4-bit uniform to 3-bit non-uniform quantization in phase. This powerful methodology dramatically simplifies the design of acoustic devices and provides a key-step towards realizing spatial sound modulators.
The popular theory that complex tool-making and language co-evolved in the human lineage rests on the hypothesis that both skills share underlying brain processes and systems. However, language and stone tool-making have so far only been studied separately using a range of neuroimaging techniques and diverse paradigms.
An existing randomised controlled trial was used to investigate whether multiple ultrasound scans may be associated with the autism phenotype. From 2,834 single pregnancies, 1,415 were selected at random to receive ultrasound imaging and continuous wave Doppler flow studies at five points throughout pregnancy (Intensive) and 1,419 to receive a single imaging scan at 18 weeks (Regular), with further scans only as indicated on clinical grounds. There was no significant difference in the rate of Autism Spectrum Disorder between the Regular (9/1,125, 0.8 %) and Intensive (7/1,167, 0.6 %) groups, nor a difference between groups in the level of autistic-like traits in early adulthood. There is no clear link between the frequency and timing of prenatal ultrasound scans and the autism phenotype.
BACKGROUND: Acute appendicitis is the most prevalent emergency surgical diagnosis in children. Although traditionally a clinical diagnosis, the diagnosis of acute appendicitis is uncertain in approximately 30% of pediatric patients. In attempts to avoid a misdiagnosis and facilitate earlier definitive care, imaging modalities such as ultrasonography have become important tools. In many pediatric studies, the absence of a visualized appendix with no secondary sonographic features has been reported as a negative study result, and a study where the appendix is not seen but demonstrates secondary features is often deemed equivocal. With ultrasound appendiceal detection rates reported at 60% to 89%, the dilemma of the nonvisualized appendix or equivocal study is frequently faced by clinicians. OBJECTIVE: This study aimed to assess the value of the nonvisualized appendix on ultrasound and the association of secondary sonographic findings in pediatric patients with acute right lower quadrant pain undergoing ultrasound, in whom acute appendicitis was a diagnostic consideration. METHODS: Retrospective case review of 662 consecutive children (age < 18 years) presenting to a pediatric emergency department with clinically suspected appendicitis, who had graded compression sonographic studies during the 24-month study period, was performed. RESULTS: The appendix could not be visualized in 241 studies (37.7%). An alternate diagnosis was identified via sonography in 47 patients (19.5%). Twenty-five patients (12.9%) were taken for surgery where 17 (8.8%) had acute appendicitis confirmed via pathology. The specificity of moderate-to-large amounts of free fluid is 98%, phlegmon at 100%, pericecal inflammatory fat changes at 98%, and any free fluids with prominent lymph nodes at 81%. The odds ratio of appendicitis increases from 0.56 to 0.64 to 2.3 and 17.5, respectively, when there were 2 and 3 ultrasonographic inflammatory markers identified. CONCLUSIONS: Although uncommonly seen, large amounts of free fluid, phlegmon, and pericecal inflammatory fat changes were very specific signs of acute appendicitis. In the absence of a distinctly visualized appendix, the presence of multiple secondary inflammatory changes provides increasing support of a diagnosis of acute appendicitis.
Aim The study aimed to use power Doppler imaging (PDI) transanal ultrasonography to produce three-dimensional power Doppler angiography images of haemorrhoidal tissue and to monitor the effects of Doppler-guided aluminium potassium sulfate and tannic acid (DGALTA) sclerotherapy. Method Ninety-six haemorrhoids in 43 patients were examined using PDI transanal ultrasonography, and DGALTA sclerotherapy was performed from April 2011 to April 2012. DGALTA sclerotherapy was conducted using a four-step injection process with pulse wave Doppler ultrasound under perianal local anaesthesia. Results A three-dimensional power Doppler angiography image of the blood flow in haemorrhoidal tissue was produced using PDI transanal ultrasonography. The cross-sectional area of blood flow in the haemorrhoidal tissue (PDI area) significantly decreased after DGALTA sclerotherapy. The PDI areas in the preoperative state and 1 and 3 months after treatment were 0.35 ± 0.27, 0.03 ± 0.05 and 0.04 ± 0.05 cm(2) (P < 0.0001). Conclusion A three-dimensional power Doppler angiography image of the haemorrhoidal tissue was technically possible and showed blood flow in the haemorrhoidal tissue to be significantly decreased after DGALTA sclerotherapy.
PURPOSE.: This study aimed to evaluate the changes in retrobulbar blood flow by using color Doppler sonography in patients who had undergone intravitreal ranibizumab injection for neovascular age-related macular degeneration (AMD). METHODS.: The study comprised 37 AMD patients who had undergone intravitreal 0.5 mg ranibizumab injection. The ophthalmic artery, central retinal artery, and short lateral posterior ciliary artery of both eyes of patients were evaluated by color Doppler sonography. Peak systolic velocity, end-diastolic velocity, and resistance index were calculated before injection, and after injection on day 7 and day 30. The pre- and postinjection values were compared using Wilcoxon signed rank test. RESULTS.: In a comparison with the preinjection values of peak systolic velocity, end-diastolic velocity, and resistance index, the postinjection values at both day 7 and day 30 showed no statistically significant difference in ophthalmic artery, lateral posterior ciliary artery, and central retinal artery (p > 0.05). Similarly, for the same parameters, pre- and postinjection values in the uninjected fellow eye showed no statistically significant difference (P > 0.05). CONCLUSIONS.: Intravitreal ranibizumab injection for neovascular AMD does not cause a significant change in the retrobulbar blood flow in either the injected eye or the fellow eye. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 2013.
This paper presents a real-time capable GPU-based ultrasound simulator suitable for medical education. The main focus of the simulator is to synthesize realistic looking ultrasound images in real-time including artifacts, which are essential for the interpretation of this data. The simulation is based on a convolution-enhanced ray-tracing approach and uses a deformable mesh model. Deformations of the mesh model are calculated using the PhysX engine. Our method advances the state of the art for real-time capable ultrasound simulators by following the path of the ultrasound pulse, which enables better simulation of ultrasound-specific artifacts. An evaluation of our proposed method in comparison with recent generative slicing-based strategies as well as real ultrasound images is performed. Hereby, a gelatin ultrasound phantom containing syringes filled with different media is scanned with a real transducer. The obtained images are then compared to images which are simulated using a slicing-based technique and our proposed method. The particular benefit of our method is the accurate simulation of ultrasound-specific artifacts, like range distortion, refraction and acoustic shadowing. Several test scenarios are evaluated regarding simulation time, to show the performance and the bottleneck of our method. While being computationally more intensive than slicing techniques, our simulator is able to produce high-quality images in real-time, tracing over 5000 rays through mesh models with more than 2 000 000 triangles of which up to 200 000 may be deformed each frame. Index Termsultrasound image simulation, medical image simulation, ray-tracing, sonography training, GPU.