Ultrasound Imaging

Example question: Assume you have a transducer made of a PZT with an acoustic impedance of 29 MRayls. If the transducer is directly coupled to soft tissue with an acoustic impedance of 1.6 MRayls, what fraction of the intensity is ​ transmitted​ into the tissue.

Surgeries of the knee are usually painful and managing postoperative pain is challenging. Various methods of analgesia are available. Epidural is considered as gold standard but after the advent of ultrasound, peripheral nerve blockade of the lower limb is gaining importance. A 50-year-old male patient posted for arthroscopic knee surgery, completed under spinal anaesthesia, was given four in one block using ultrasound. The point of entry of the needle was in lower thigh where the femoral artery dips down deep. 30ml of 0.25% bupivacaine was given in the space above it. Postoperatively, the time of first systemic analgesia was noted which was eight hours after full regression from spinal. Peripheral nerve blocks of the lower limb for knee surgeries usually target only the femoral component. Addressing the sciatic component with a single injection is a real challenge and we did it to block the four nerves with a single point injection. We conclude 4 in 1 block is useful as a postoperative analgesic technique in knee surgeries.

We present the case of a patient with a history of unquantified fever and dyspnea of 1 week of evolution, who subsequently tested positive for COVID-19. He also reports presenting 2 months of evolution of increased testicular volume on the left side, without any other symptomatology. In the testicular ultrasound, there is evidence of a mass that occupies most of the left testicular pouch, of heterogeneous echo texture. Contrast tomography of the chest, abdomen and pelvis showed bilateral pleural effusion with multiple mediastinal, abdominal and pelvic adenopathies, as well as multiple distant metastases.

We describe methods to extract, measure and visualize three-dimensional shapes from
Intracoronary Ultrasound (IVUS) videos recorded in vivo, with image segmentation for
lumen and intima thickening, and functional model recovery from discrete representations,
with IVUS video segmentation, probe motion recovery, and verification and applications
of all the methods.
We have developed a novel time-variant shape extration method that is based on the
principle of IVUS video formation and heart vessel phasic motion. We have demonstrated
that image distance, computed by multiresolution approach, is an efficient and reliable way
to recover phase information directly from cardiac IVUS image sequences. The reconstruction
is fully automatic and takes linear time with respect to the number of frames. It is a robust
approach and had been successfully applied to low-image-quality digitized videos. The
recovered shapes not only show strong visual coherence but also detailed phasic changes of
important anatomical and physiological structures. The recovered three-dimensional model
is properly aligned by three-dimensional registration techniques.
Biomechanical studies such as stress analysis require a smoothmodel. For this, we have
introduced a new functional model recovery method that computes an implicit polynomial
representation from any discrete pointset input. This new minimal description length based
model is both stable and repeatable.
We have developed a shortest path segmentation algorithm that is based on line-integral
edge weight. We have shown that this algorithm performs well for extracting a global optimal
path for a curved area of interest from speckle images. We apply the algorithm to
IVUS videos to analyze the time-dependency of the morphological characteristics of epicardial
arteries. We guide the video segmentation process with an automatically-computed
segmentation graph. Using this, we have achieved significant performance gain over traditional
video segmentation algorithms, and obtaining vessel lumen contours that match well
with those traced by an expert.
This system has been applied to animal studies, to visualize and measure intima thickness
and lumen areas in response to acute mean arterial pressure changes, and to track
changes of vessel size and intima thickening for a period of over 15 months.

Chest ultrasonography is a useful tool for assessing disease activity in the peripheral lung parenchyma, pleura, chest wall, diaphragm, and mediastinum. Ultrasound imaging also provides highly useful guidance in invasive diagnostic and therapeutic procedures. The main advantages of this imaging technology are the absence of ionizing radiation and the possibility of real-time bedside applications. The chief indications and limitations of chest ultrasonography and the principal sonographic signs are reviewed.

A 38-year-old woman presented with fever, right flank pain, and a clinical diagnosis of pyelonephritis. Work-up revealed the presence of a crossing arterial branch causing obstruction of the superior infundibulum of the right kidney, which is an uncommon cause of nephralgia and urinary infection initially described by Fraley in 1966. Intravenous urography, retrograde pyelography, and angiography remain the mainstay of diagnosis, much as in the initial descriptions of this entity. [131I]Hippuran imaging, with analysis of the upper and lower pole regions of interest, provides a simple yet powerful method of evaluating functional and excretory changes in the superior infundibulum, and has proved more efficacious than previously reported whole-kidney renograms. Renal scintigraphy represents a relatively noninvasive method of serial functional examination in this disorder. Ultrasound imaging, by monitoring upper-pole dilatation, may provide complementary morphologic information important...

Abstract
Question: Are women in semi-urban city of Nigeria aware of alternative route of  ultrasound scanning in early pregnancy aside trans-abdominal route(TAS) and what is the  level of acceptance of trans-vaginal ultrasound scanning(TVS) among them?
Summary Answer: Only about one-fifth (16.4%) of women who have been pregnant  ever are aware of TVS as an option in pregnancy assessment, among which only 52.6% of  them know that TVS is preferred in some pregnancy conditions over TAS. Less than one third (28.8%) will accept to have TVS done.
Known Already: Several studies in western world have looked at acceptability of  TVS among women for various indications with a wide range acceptability of 43% to 96%  depending on the content of questionnaire. Very few studies have looked at acceptability in  Nigeria. Willingness to have TVS done was quoted by Atalabi et al. as 84%. Study Design, Size and Duration: This was a cross-sectional study over 8-week  period among unselected women who came for routine ante-natal clinic in two tertiary hospitals in Osogbo, Nigeria. The plan was to administer at least 300 questionnaires. Verbal
consent was secured after due counselling by research assistant.
Participants, Settings, Method: Pregnant women attending booking clinics of  Lautech teaching hospital and Asubiaro general hospital were approached as convenient  to participate in the study using self-administered questionnaire though queries about  questionnaire were answered on spot by research assistant. Verbal consent after due
counsel was accepted. Descriptive and multivariate analysis done using SPSS Statistics  version 20 software. Main results: Total of 347 participants. Response rate was 94.3%. Two out of three  participants (68%) had tertiary level of education. Of the participants 83.6% think ultrasound  scanning is not harmful. Only about one-fifth (16.4%) of women who have been pregnant  ever are aware of TVS as a tool in women assessment. Among those who are aware of  TVS over 80% are unsure of conditions when TVS is preferred to TAS. The leading negative
expected feeling among participants (74.7%) who responded if they were asked to do TVS  was expectation of more pain compared to TAS 41.2% will consider giving consent only  after discussing it with husband. Less than one-third (28.8%) of women who have ever been
pregnant will accept to have TVS done.
Limitation: Participants are within semi-urban area even though two-third of them has  tertiary level of education. The environment of study may be a strong factor in limiting  exposure & thus awareness of TVS.
Wider Implications of Findings: There is urgent need to educate the populace  including men via various media houses including social media on the safety & advantages  of TVS in assessment of women either in pregnancy or outside of pregnancy.  Only about one-fifth (16.4%) of women who have been pregnant ever are aware of TVS
as a tool in women assessment, Less than one-third (28.8%) of women who have ever been  pregnant will accept to have TVS done.
Keywords: Awareness TVS, Pregnant Women

The unique anatomic features of the ophidian organs have direct consequences on the approaches used and the structures viewed during an ultrasonography examination; these include the organs mobility in the coelomic cavity and the particular aspect of the organs.
Assessment of optimal approaches of ultrasonography in the boid snakes, so to identify the normal ultrasonographyc anatomy of the coelomic organs.
The biological material was represented by 4 boid snake: 3 Boa constrictor (Boa constrictor imperator) and 1 Burmese Python (Python molurus bivittatus); 1 male and 3 female, weighing between 2.5 and 20.7 kg and measuring from 1 to 3 m. The snakes were each held both in ventral and dorsal recumbency, with no anesthesia necessary, only physical restraining. For the ultrasonography of coelomic organs examination, an ultrasound Mindray DC-6 unit equipped with a 7.5-10 MHz linear was used. Ventral and intercostals approaches were used, evaluation and measurements being assessed in B mode. In some cases Color Doppler was used to visualize the blood flow in the ophidian organs.
B mode ultrasonography shows the heart that could be taken as a mark point for identifying the other coelomic organs. There were put in evidence the intestine, the liver and gall bladder, the kidney and the ovary. Vascularization of the liver, kidney and the heart was evaluated through Doppler.
The ultrasound examination is a non-invasive method that could constitute a useful tool in identifying different pathologies located at the coelomic level.

The ultimate diagnosis of prostate cancer involves histopathology analysis of tissue samples obtained through prostate biopsy, guided by either transrectal ultrasound (TRUS), or fusion of TRUS with multi-parametric magnetic resonance imaging. Appropriate clinical management of prostate cancer requires accurate detection and assessment of the grade of the disease and its extent. Despite recent advancements in prostate cancer diagnosis, accurate characterization of aggressive lesions from indolent ones is an open problem and requires refinement. Temporal Enhanced Ultrasound (TeUS) has been proposed as a new paradigm for tissue characterization. TeUS involves analysis of a sequence of ultrasound radio frequency (RF) or Brightness (B)-mode data using a machine learning approach. The overarching objective of this dissertation is to improve the accuracy of detecting prostate cancer, specifically the aggressive forms of the disease and to develop a TeUS-augmented prostate biopsy system. Towards full-filling this objective, this dissertation makes the following contributions: 1) Several machine learning techniques are developed and evaluated to automatically analyze the spectral and temporal aspect of backscattered ultrasound signals from the prostate tissue, and to detect the presence of cancer; 2) a patient-specific biopsy targeting approach is proposed that displays near real-time cancer likelihood maps on B-mode ultrasound images augmenting their information; and 3) the latent representations of TeUS, as learned by the proposed machine learning models, are investigated to derive insights about tissue dependent features residing in TeUS and their physical interpretation. A data set consisting of biopsy targets in mp-MRI-TRUS fusion-biopsies with 255 biopsy cores from 157 subjects was used to generate and evaluate the proposed techniques. Clinical histopathology of the biopsy cores was used as the gold-standard. Results demonstrated that TeUS is effective in differentiating aggressive prostate from clinically less-significant disease and non-cancerous tissue. Evidence derived from simulation and latent-feature visualization showed that micro-vibrations of tissue microstructure, captured by low-frequency spectral features of TeUS, is a main source of tissue-specific information that can be used for detection of prostate cancer.

Abstract: By appropriating both medical and communication technologies, the gender- reveal party has recently emerged as a ritual performance centered on a dramatically staged disclosure of the sex of a gestating fetus. The gender-reveal party is an example of the new forms of ritualization that take place during pregnancy in 21st-century North America. Typically, the focal point of the party is when the future parents cut a cake whose inside color (blue or pink) reveals the sex of the fetus. This article examines the ritual dynamics and creativity at work in the preparation, the performance and the mediated dissemination of this festive occasion. Key elements of the ritual will be described, as well as its conditions of emergence in a context where neither medical nor religious institutions offer ritual options deemed appropriate enough for celebrating joyfully and emotionally during pregnancy.

Résumé : À travers une appropriation combinée de technologies médicales et des technologies de communication, la gender-reveal party (« la fête où l’on révèle le genre ») a récemment émergé comme une performance rituelle centrée sur la révélation par une mise en scène dramatique du sexe du fœtus en gestation. La gender-reveal party est un exemple des nouvelles formes de ritualisation qui prennent place pendant la grossesse au 21ème siècle en Amérique du Nord. Son point culminant consiste généralement à découper un gâteau dont la couleur intérieure (bleue ou rose) révèle le sexe du fœtus. Cet article examine les dynamiques rituelles et la créativité à l’œuvre dans la préparation, la performance et la dissémination médiatisée de cette occasion festive. Les éléments clés de ce rituel seront soulignés, ainsi que ses conditions d’émergence dans un contexte où ni les institutions médicales ni les institutions religieuses n’offrent d’options rituelles considérées comme appropriées pour des célébrations joyeuses et émotionnelles pendant la grossesse.

Aims: Understanding the knowledge gaps among the public regarding radiation protection of each modality has helped to assess the community awareness and perception, which reflects our urgent need for more education for the public. This project aims to evaluate the knowledge levels of patients undergoing medical imaging procedures is regarding the risk and benefits by providing sufficient information regarding their specific medical imaging technique upon examination. Study Design: A prospective study with a special questionnaire to collect data. Place and Duration of Study: Subjects: Different departments of Radiology in different hospitals, Jeddah, Saudi Arabia, for 3 months. Methodology: The survey was conducted in Jeddah, Saudi Arabia, to include four major hospitals. The sample of the study included 500 patients (125 for each hospital). Patients are aged 18 years and over were referred by physicians for a radiological examination, including different radiologic modalities. Results: It was found that 52% of patients were provided the information about radiology examination. The mean scores of questions ranged from 69% to 76%. So, there was a strong positive correlation between the radiology examination information received by patients and the radiation questions' score.

Abstract

The piezoelectric effect and its converse are the primary means used in biomedical ultrasound for converting acoustical energy into electrical energy and vice versa. Piezoelectricity has found many bioengineering applications ranging from ultrasound imaging and therapeutics, to piezoelectric surgery and microelectromechanical systems, and to biomedical implants with associated energy harvesting. Because of its fundamental importance to the proper functioning of most medical ultrasound systems, it is important to gain a general understanding of the effect, the history of its development and from this, an appreciation of its limitations and advantages in the generation and detection of ultrasound. This article describes the historical evolvement associated with its use in relation to most medical ultrasound applications and is intended to serve as an introduction for non-expert readers.

L’échographie est un outil non invasif, non irradiant, réalisable en temps réel et précis. Ses capacités diagnostiques lui permettent une application dans les champs musculo-squeletique, uro-gynécologique et cardio-respiratoire en kinésithérapie. L’échographe peut être utilisé dans le cadre du bilan diagnostic kinésithérapique, dans le suivi du traitement, comme moyen de feedback et dans la réévaluation de la prise en charge rééducative. La qualité de la formation de base sera ainsi l’un des enjeux du développement de l’échographie en France pour que celle-ci s’intègre pleinement dans une démarche raisonnée et basée sur les preuves.

Objectives
External carotid artery (ECA) stenosis is an independent mortality predictor. Additionally, concomitant ECA and internal carotid artery (ICA) stenoses progression has been associated with an increased risk of ipsilateral ischemic events in asymptomatic patients. Universally accepted ECA duplex velocity criteria, for the prediction of stenosis, do not exist.

Methods
Consecutive patients undergoing angiography and carotid duplex assessments were compared (n=140). ICA, common carotid artery (CCA) and ECA peak systolic velocities (PSV) were recorded. ECA/CCA PSV ratio was calculated. These parameters were compared with angiographic ECA measurements. Receiver-operator curve (ROC) analysis were used to determine optimal criteria in identifying ECA stenosis of >50%.

Results
In patients with little ipsilateral ICA disease, for the detection of ECA stenosis of >50%, an ECA PSV >148 cm/s provided sensitivity 80%, specificity 76.2%, and an overall accuracy of 77.1%. An ECA/CCA PSV ratio of 1.45 demonstrated sensitivity 73.7%, specificity 66.7%, and an accuracy 68.2%.

In patients with ICA stenosis > 50%, for the detection of ECA stenosis of > 50%, an ECA PSV >179 cm/s provided sensitivity 50%, specificity 79.6%, and overall accuracy 71.3%. An ECA/CCA PSV ratio of >1.89 provided sensitivity 71.9%, specificity 72.7%, and overall accuracy 72.5%.

Conclusion
ECA PSV an ECA/CCA PSV ratios appear useful metrics for the prediction of unilateral high-grade ECA stenosis.

The diagnosis of hypertrophic pyloric stenosis (HPS) with ultrasonography (US) is dependent on measurements of pyloric diameter (PD), pyloric length (PL), and muscle thickness. The authors were unable to confidently diagnose the condition with US in 45% of patients who underwent surgery for HPS because all three criteria were not fulfilled. An overall measurement of the "amount" of pyloric hypertrophy was introduced: pyloric volume (PV), which was equated to 1/4 pi x PD2 x PL. No overlap was found between patients with HPS (n = 22; PV = 3.13 mL; range, 1.4-5.1 mL) and asymptomatic control subjects (n = 28; PV = 0.65 mL; range, 0.2-1.3 mL) or symptomatic subjects without HPS (n = 25; PV = 0.86 mL; range, 0.4-1.3 mL). A positive correlation was found between age at diagnosis and PV, a finding reflecting that HPS is an acquired condition. In patients less than 4 weeks of age, the criterion of PV greater than or equal to 1.4 mL proved to aid in the identification of early HPS more accurately than any existing criteria.