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Algorithm of HP Diagnostic

BÀI SOẠN SIÊU ÂM GIẢI PHẪU HỌC DÀNH CHO SINH VIÊN ĐẠI HỌC Y KHOA TÂN TẠO

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Orienting in Transabdominal Studies 

There are two primary orientations of the transducer in relation to the patient when performing ultrasound studies. 

 @ Transverse - perpendicular to the long axis of the patient, 

 @ and longitudinal - parallel to the long axis of the patient. 

The top of the monitor always corresponds to what is closest to the transducer, while the bottom of the monitor corresponds to tissues that are farther away.

It is important to determine which side of the transducer corresponds to the left side of the monitor, and which side corresponds to the right side of the monitor.

When the transducer is held in a transverse orientation, images of the patient's anatomy are taken in the axial plane. The left side of the monitor should display structures on the patient's right side, and the right side of the monitor should display the patient left. This is the same as a properly oriented radiograph.

When the transducer is held in a longitudinal orientation, images of the patient's anatomy appear in the sagittal plane. The left side of the monitor should display more cranial tissues, and the right side of the monitor displays more caudal structures.

BILIARY ATRESIA TYPE IIIa

LEYDIG CELL TUMOR: ULTRASOUND FINDINGS

SUPERIOR THYROIDAL ARTERY and CAROTID STENTING

SONOGRAPHY of the ACCESSORY HEAD of the BICEPS BRACHII

ABSTRACT

Anatomic variations in the anterior aspect of the shoulder, such as an accessory head of the biceps brachii muscle, are not uncommon. The magnetic resonance imaging and arthroscopic appearance of the accessory head of the biceps brachii has been recently described. This series demonstrates the sonographic appearance of the accessory head of the biceps brachii in the bicipital groove. It is an asymptomatic, flat, echogenic structure with average measurements of 7.7 × 1.2 mm in cross section. Knowledge of this anatomic variant can avoid the misdiagnosis of a longitudinal split tear and improve the accuracy of sonography.

Anatomic variations in the anterior aspect of the shoulder are not uncommon, with a frequency ranging from 2% to 18% depending on the ethnic group.1–7Examples include an accessory head of the biceps brachii muscle, coracobrachialis brevis muscle, accessory subscapularis muscle, and variants of the pectoralis muscles.1 Correct identification of normal variants is important to avoid misdiagnosis of disorders and for accurate diagnosis.1,4,8,9

Sonography has been shown to be an excellent imaging modality to evaluate muscles and tendons, with advantages and disadvantages compared to magnetic resonance imaging (MRI).10,11 Recently the MRI and arthroscopic appearance of the accessory head of the biceps brachii has been described.1,9,12–14 The purpose of this series is to demonstrate the sonographic appearance of the accessory head of the biceps brachii in the bicipital groove. To our knowledge, no prior ultrasound articles describing this anatomic variant have been published. Knowledge of this anatomic variation and its normal appearance on sonography can help prevent false-positive diagnoses of proximal biceps disorders.8,9,15

GRAVE DISEASE and PAINLESS THYROIDITIS

Elastography May Avoid Needless Biopsies of Thyroid Nodules

By Erik L. Ridley, AuntMinnie staff writer

September 10, 2014 -- Thanks to its high negative predictive value, ultrasound elastography with intrinsic compression may be able to reduce by one-third the number of unnecessary biopsies performed on calcified thyroid nodules, according to research published in the October issue of Ultrasound in Medicine and Biology.

In a study involving 65 calcified thyroid nodules, a team of researchers led by Dr. Min-Hee Kim of Catholic University in Korea found that elastography yielded 95.8% negative predictive value in detecting malignancy. Furthermore, more than one-third of biopsies on calcified nodules could have been avoided based on elastography results.

"Intrinsic compression elastography can be used in conjunction with B-mode [ultrasound] to reduce the number of [fine-needle aspiration] biopsies of calcified thyroid nodules," wrote Kim and colleagues, who also came from the University of Washington and Pohang University of Science and Technology.

Confounding calcification

Although calcification in thyroid nodules is an important ultrasound feature that suggests malignancy, and current major guidelines strongly recommend that calcified nodules larger than 5 mm be biopsied, calcification can be present in both malignant and benign nodules. As a result, many benign nodules end up being biopsied unnecessarily (Ultrasound Med Biol, October 2014, Vol. 40:10, pp. 2329-2335).

Ultrasound elastography has been shown in a number of studies to provide high sensitivity and specificity for detecting malignant thyroid nodules. But the lack of interobserver agreement in elastography -- due to variability in data acquisition and scoring -- is a major reason why the method has not been widely adopted in clinical practice, according to the group.

Standard elastography utilizes external compression, with the pressure of the transducer providing the tissue compression that results in the tissue strain measured by elastography. But other researchers have found that elastography utilizing intrinsic compression -- with pressure provided by forces inside the body such as carotid artery pulsation -- could offer better performance. The payoff would be better interobserver and intraobserver agreement.

As a result, the team sought to determine if intrinsic compression elastography could perform well for characterizing thyroid nodules with calcification. The researchers recruited 188 patients with 229 thyroid nodules who were referred to Seoul St. Mary's Hospital from May 2011 through January 2012 for a fine-needle aspiration (FNA) biopsy.

All patients received both ultrasound and elastography exams prior to FNA biopsy. B-mode images were acquired using an iU22 ultrasound system (Philips Healthcare) with a 5- to 12-MHz high-resolution linear probe.

Blinded to the patient's clinical information as well as cytologic and elastography results, a radiologist with 15 years of experience retrospectively reviewed the B-mode ultrasound images and extracted nodule features such as echogenicity, margin, shape, and presence of calcification, according to the researchers. Based on those ultrasound features, the nodules were categorized into three groups: benign, indeterminate, and suspicious for malignancy.

The elastography studies were performed by three endocrinologists with more than one year of experience with intrinsic compression elastography. An Accuvix XG (Samsung Medison) scanner with an L5-13 linear transducer was used in the study, and no external compression was performed while the ultrasound data were acquired, according to the team.

The researchers employed a quantitative scoring method -- elastic contrast index (ECI) -- for the elastography results; a higher ECI value suggests a stiffer nodule and an increasing likelihood of malignancy. A minimum of two ECI measurements were gathered in the imaging plane that showed the thyroid nodule's largest diameter in the transverse view, according to the authors.

Diagnostic accuracy

Next, the researchers determined elastography's diagnostic accuracy by varying the ECI cut-off value in order to find the sensitivity and specificity combination that yielded the maximum geometric mean (sensitivity multiplied by specificity) in detecting malignant nodules. They also calculated positive and negative predictive values.

Of the 196 nodules in the study, 42 were malignant; all were papillary thyroid carcinoma. The mean nodule size was 9 ± 4.17 mm for malignant nodules, significantly smaller than the 11.31 ± 6.1 mm mean size for benign nodules.

The researchers observed that the mean ECI value of malignant nodules (4.51 ± 2.22) was significantly higher than the value for benign nodules (2.98 ± 1.47, p < 0.001). They then calculated elastography's performance, with a mean ECI cut-off value of 3.11 indicating malignancy.

The radiologist classified four of the 65 (45 benign and 20 malignant) nodules with calcification as benign; three of the four were found to be benign under elastography. The remaining 61 nodules with calcification were categorized as either indeterminate (29) or suspicious for malignancy (32). With elastography, however, nine of the 32 nodules classified as suspicious for malignancy were determined to be benign, a diagnosis that was confirmed by biopsy.

Furthermore, 12 of the 29 cases that were considered by the radiologist to be indeterminate were judged to be benign on elastography. Biopsy results confirmed the benign diagnosis in 11 of 12 cases; one malignant nodule with rim classification was incorrectly classified as benign using elastography, according to the group.

Elastography's performance in nodules with calcification was as follows:

• Sensitivity: 95%
• Specificity: 51.1%
• Positive predictive value: 46.3%
• Negative predictive value: 95.8%

In all, 23 benign calcified nodules (51.1% of benign calcified nodules) were correctly classified by elastography, whereas only four (8.9%) were correctly classified by B-mode ultrasound, the authors wrote.

The study demonstrates a potential role for elastography in the management of calcified thyroid nodules, according to the researchers.

"With the use of elastography on those calcified nodules, for which B-mode [ultrasound] has low specificity (i.e., 8.9%) in detecting malignancy, FNA biopsy could have been avoided in 23 (35.4%) of 65 calcified nodules," they wrote. "In terms of reducing the number of FNA biopsies, our study found that elastography had a clinical impact similar to that reported in a previous study that evaluated the usefulness of elastography in calcified breast lesions."

Copyright © 2014 AuntMinnie.com

HOW to MEASURE VOLUME of SEMINAL VESICLE

TB NODES in the NECK

Discussion

High-resolution sonography has been widely used for assessment of lymph nodes in the neck and has been established as a first-line imaging tool.^15–17 The main roles of sonography in patients with a clinical suspicion of tuberculous lymphadenitis in the neck are detection and characterization. Furthermore, sonographic guidance is available worldwide for diagnostic and interventional procedures. As a diagnostic tool for tuberculous lymphadenitis in the neck, sonography may be behind sonographically guided fine-needle aspiration or PCR. Recently, one study comparing sonographic diagnosis, sonographically guided fine-needle aspiration, and PCR for detecting tuberculous lymphadenitis demonstrated that the diagnostic values of PCR alone and in combination with sonographically guided fine-needle aspiration were higher than those of other methods.¹⁸

Among the 4 individual sonographic features, a predominantly hypoechoic node with a heterogeneous echo pattern and intranodal necrosis showed high specificity and a high PPV but low sensitivity. Two sonographic features (poorly defined anechoic areas in the perinodal soft tissue with or without sinus and abscess formation and a vascular distribution with apparently avascular areas and displaced vascularity on color Doppler sonography) showed high sensitivity and a high NPV but low specificity. Therefore, no sonographic features with both high sensitivity and specificity were found. Among the sonographic features, poorly defined anechoic areas in the perinodal soft tissue have been known to indicate soft tissue edema.^4,14 In this study, 13 patients with tuberculous lymphadenitis showed poorly defined anechoic areas in the perinodal soft tissue. Among them, 7 (53.8%) had a minimal amount of pyogenic aspirates on sonographically guided fine-needle aspiration of these sites; thus, we believe that an early-stage abscess is more likely than soft tissue edema. For clarity, further studies may be required.

For sonographic diagnosis, the “2 or more” category was more accurate for diagnosis of tuberculous lymphadenitis than the “1 or more,” “3 or more,” and “4” categories. Of all 79 patients, 62 (78.5%) were classified as “1 or more,” 46 (58.2%) as “2 or more,” and 22 (27.8%) as “3 or more.” Of the 40 patients with tuberculous lymphadenitis, 40 (100%) were classified as “1 or more,” 38 (95%) as “2 or more,” and 20 (50%) as “3 or more.” In comparison with the “2 or more” category, the “1 or more” category had high sensitivity but low specificity, and the “3 or more” category had high specificity and a high PPV but low sensitivity. However, we did not investigate a diagnostic index for sonographic diagnosis of tuberculous lymphadenitis according to different combinations of the 4 sonographic features.

There were several limitations to this study. First, it was a retrospective study. In each case, limited sonograms were used. Second, a single radiologist performed the sonographic examinations, sonographically guided fine-needle aspirations, and retrospective image analyses of lymph nodes in the neck, but the image analyses with blinding to all patient information were done 2 to 3 years after neck sonography and fine-needle aspiration. Third, 5 patients with tuberculous lymphadenitis were confirmed as having a reactivated type, but we did not discriminate between them. Finally, color Doppler sonography was used for evaluation of nodal vascularity in all cases, whereas power Doppler sonography was performed with color Doppler sonography in a minority. However, the sensitivity of color Doppler sonography is not different from that of power Doppler sonography because of advances in technology.^12,13

In conclusion, the study results showed that no sonographic feature had both high sensitivity and specificity for identification of tuberculous lymphadenitis, but the diagnostic accuracy of the “2 or more” category was higher than those of other categories. Therefore, our sonographic diagnostic method may be useful for detection of tuberculous lymphadenitis in clinically suspected patients.

The Ultrasound: How It Works

While we’ve all seen ultrasound pictures of our own children or perhaps the children of friends, most people don’t know exactly how an ultrasound machine produces images.

As the name suggests, it’s all about sound. Ultrasound waves are simply sound waves that the human ear cannot detect. The ultrasound technician uses a probe which is placed on the skin, and this probe sends out pulses of ultrasound waves. This sound reflects off of human tissue as an echo. The echo is then used to create an image.

In many ways, it is similar to echolocation. This is what happens when bats and other animals use sound to help them identify objects that they cannot see. Sonar is another example of how sound waves are bounced off of objects in order to locate them. With an ultrasound machine, the importance is not just in locating an object but also studying it for medical purposes.

Obviously, it is standard practice for women to undergo one or more ultrasound exams during their pregnancy. However, many other doctors use ultrasound technology to study other parts of the body, including organs such as the heart. The ultrasound provides an excellent, non-invasive way to look for a wide variety of medical issues. It also has an advantage over x-rays in that no radiation is transmitted to the patient during the test. Cardiologists, urologists, gynecologists and obstetricians are some of the doctors that use ultrasounds, but emergency room doctors and emergency medical technicians also sometimes use these machines, particularly hand-held or portable ultrasounds.

A standard ultrasound usually has several different parts. The part that comes into contact with our body is known as a transducer probe, and this is the piece that actually sends out the sound waves and then receives the echo once it reaches its target within our body, which might be a fetus or perhaps the heart. An ultrasound machine also includes a computer and a monitor to display the pictures. Usually, there is a printer as well, either as part of the whole machine or connected by cables. The computers also allow the technician to place the images on CDs.

ELASTO ULTRASOUND GUIDELINES: Part 2. CLINICAL APPLICATIONS

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ELASTO GUIDELINES: PART 2. CLINICAL APPLICATIONS

Future perspectives

As befits a new method, elastography is being used in new applications which as yet lack sufficient strength of evidence to justify their inclusion in these Recommendations, though their exclusion should not be taken as implying that they may not prove to be of clinical value once more experience is gained. The topics below are an incomplete list of those that are of clinical interest but whose clinical value is still to be confirmed.

Elastography of superficial lymph nodes, for example in the neck or inguinal regions, is a promising application, where an increase in stiffness would be expected in malignancy but might also occur in inflamed nodes [177, 178].

Intraoperative elastography has been applied to the brain to guide the surgeon to stiffer regions that represent tumours and improve the precision of their resection [179, 180].

Elastography of the uterine cervix to assess the softening that precedes normal dilatation before delivery is potentially important. Premature delivery is a major cause of fetal death, which could be reduced if a simple and reliable means of identifying premature softening could be developed [181].

Testicular tumours are harder than the surrounding gland on palpation and this might be a useful application of elastography to aid the distinction between the commoner malignancies and the rarer less invasive tumours such as Leydig cell tumours, which can be managed with tissue-sparing surgery [182].

Anal incontinence, most commonly an obstetrical injury, leads to scarring which is stiffer than the normal sphincter muscles; a preliminary report focusses on the presurgical findings, with promising results [128] whereas postoperative evaluation was disappointing [183]. Elastography has been used in rectal and anal carcinomas where it improves the discrimination between adenoma and cancer [129] and the differentiation of T2 and T3 stages of rectal cancer. Although this improved differentiation has so far not been evaluated, it seems convincing because inflammatory changes appear softer than the usually harder tumours.

Perineal ultrasound is an effective method for imaging perianal inflammatory lesions (e. g. in Crohn's disease) but is too rarely used. Generally speaking, acute inflammatory lesions are softer and chronic lesions harder in comparison to the surrounding tissue [184].

Arterial and plaque stiffness has been studied in preliminary investigations [135, 185, 186] and might form a clinically useful way to assess vulnerable plaque.

Promising results have been reported on the clinical use of SE for tendon disease such as for common extensor origin tendons in order to depict tendon and fascia involvement in lateral epicondylitis [187], for plantar fascia where stiffness changes with age and disease [188] and for trigger finger, where there is increased stiffness of the flexor tendon which decreases after steroid injections [189]. Preliminary studies also show the potential use of strain elastography in localising myofascial trigger points to inject with botulin toxin [190] and for diagnosing and monitoring of inflammatory myopathies by showing changes in muscle stiffness in correlation with elevated serum markers [173]. Preliminary data are available on stiffness measurements and shear wave velocities of normal muscle and tendon using shear wave techniques [175, 191].

Other applications will no doubt emerge as more experience is gathered.

ULTRASOUND IMAGING of a CHITOSAN NERVE CONDUIT

Evaluating Chitosan Nerve Conduits That Bridge Sciatic Nerve Defects Visualized Using Ultrasound Imaging

By Medimaging International staff writers
Posted on 27 Aug 2014

Image: Ultrasound image of the morphology of a chitosan nerve conduit in a rat model of sciatic nerve defects at three weeks after modeling (Photo courtesy of Neural Regeneration Research journal).

The first use of ultrasound has been used by Chinese researchers to noninvasively observe the changes in chitosan nerve conduits implanted in lab rats over time. 

The investigators reported that newer, simpler, and more effective ways are needed to better assess the outcomes of repair using nerve conduits in vivo. The new technology distinctly revealed whether there are unsatisfactory complications after implantation, such as fracture, collapse, bleeding, or unusual swelling of the nerve conduits; and reflected the degradation mode of the nerve conduit in vivo over time. 

Ultrasound is a common noninvasive clinical detection modality that has been used in many fields. However, ultrasound has seldom been used to observe implanted nerve conduits in vivo. 

Dr. Hongkui Wang and coworkers from Affiliated Hospital of Nantong University (Nantong, Jiangsu Province, China) reported on their findings July 15, 2014, in the journal Neural Regeneration Research. Ultrasound, as a noninvasive imaging modality, they noted, can be used as a supplementary observation technique during standard animal research on peripheral nerve tissue engineering. 

DẤU HIỆU SIÊU ÂM CỦA VIÊM HANG VỊ DO H. pylori

GASTRIC ULTRASOUND: ANTRAL GASTRITIS and H.pylori.

Sonography can be used effectively to evaluate the stomach and duodenum. A mucosal thickness greater than 4 mm in the gastric antrum may suggest the presence of gastritis. Marked transmural gastric wall thickening is typical of gastritis, with documented resolution after appropriate therapy. Loss of the normal multilaminar gut signature at the posterior wall of the gastric antrum is another useful sonographic characteristic of inflammation.

The mucosa often seems to be hyperenhancing adjacent to the hypoattenuation of edematous submucosa. 

Antral gastritis displays a spectrum of findings on double-contrast upper gastrointestinal tract examinations, including thickened rugal folds, erosions, mucosal nodularity, and antral striae. Wall thickening that is focal, eccentric, and enhancing can resemble a malignant tumor, and further steps must be taken with this possibility kept in mind.

Our study is unique and original, since we suggest that antral wall and mucosal layer thicknesses as well as the mucosal layer-to-antral wall thickness ratio may be predictive parameters for detection of antral gastritis and H pylori infection on sonography. Cutoff values have not yet been established, and further controlled studies are necessary for validation and standardization of these parameters.

Inflammation and structural changes in the gastric mucosa seem to be more prominent in the presence of H pylori. Therefore, careful investigation for detection of H pylori and effective treatment for its eradication should be mainstays of the management strategy.

This study recommends that sonography of the gastric antrum can be beneficial for patients with presumed antral gastritis. If thickening of the antral walls and mucosal layers is detected, antral gastritis and H pylori infection must be kept in mind, and further diagnostic and therapeutic steps should be taken accordingly. Even though the sonographic appearance of antral thickening can rarely be found in healthy individuals, this characteristic appearance should strongly suggest gastric disease, necessitating an upper gastrointestinal series. 

There are several noninvasive methods for evaluating the severity of inflammation in the stomach and the presence or absence of H pylori infection, such as a serum pepsinogen test, including pepsinogen I/II, pepsinogen II, and immunoglobulin G antibody for H pylori. In this study, we found that sonography of the stomach may be quite useful for noninvasive evaluation of the antrum. Radiologists should be aware of the usefulness of these specific criteria in the evaluation of gastric wall thickening on sonography to better differentiate gastritis or a normal stomach from malignant or potentially malignant lesions that warrant further diagnostic evaluation.

Our study had several limitations. Since we only measured the gastrointestinal wall in white participants in Gumushane, Turkey, the reference values may not be transferrable to populations with other diets or ethnicities.

In addition, gastrointestinal wall thickness differs with the ages, heights, weights, sexes, and smoking habits of patients. Some history details and factors that may influence the outcome may not haven been completely documented. Another limitation of our study was the lack of absolute proof of antral gastritis in all cases, as no perfect reference standard exists for this diagnosis. Furthermore, the wall thickness in vivo can be influenced by muscular contraction, especially in the gastric antrum. The correlation between the wall thickness evaluated by sonography and the real thickness of the stomach as determined by macroscopic features (or histologic sections) of resected stomach may well be different. However, a single 20-mg dose of butylscopolamine was administered via an intramuscular route before the sonographic examinations in all patients in our study. In addition, the degree of atrophic change (or degree of inflammatory cell infiltration) that may influence the degree of wall thickness in H pylori–positive patients was not considered in this study. Due to these restrictions, associations should be interpreted with caution. Further prospective and controlled studies with larger patient populations are warranted for making more accurate interpretations of the sonographic findings of antral gastritis and H pylori infection of the stomach. In terms of methods, we have used fasting guidelines and intramuscular administration of a pharmacologic agent.

Since most patients present with generalized abdominal symptoms, and routine use of this protocol would be impractical in most busy ultrasound practices, a fluid-filled antrum can be alternatively used for measuring the wall layers.

The main limitation of this study was the relatively small number of patients. Furthermore, the format of expressing average measurement data for the 3 groups may not allow for determination of threshold values and true-positive and -negative rates. Because of these restrictions, associations should be interpreted with caution. However, this article raises awareness of sonographic clues and will lead to further studies of this method.

In conclusion, our results suggest that antral gastritis caused by H pylori infection is associated with characteristic features such as thickening of the antral walls and mucosal layers on sonography. Thus, these clues may be useful for diagnosis of gastritis cases that require further investigation and may avoid at least some unnecessary interventions and measures.