VÌ SAO NÊN SIÊU ÂM KHỚP VAI

Shoulder Sonography: Why We Do It

  Sharlene A. Teefey, MD
 Mallinckrodt Institute of Radiology, St Louis, Missouri USA.
J Ultrasound Med 2012; 31:1325–1331

 

One of the most common causes of shoulder pain is rotator cuff disease. It is the third most prevalent musculoskeletal disorder after low back and neck pain. Shoulder pain is usually due to one of several causes: subacromial impingement and bursopathy, tendinopathy, a tendon tear, a frozen shoulder, ligamentous instability, and osteoarthritis. Rotator cuff disease (tendinopathy or tear) highly correlates with increasing age. In one study, the average age for patients with a painful unilateral partial- or full-thickness tear was 58.7 years, and it was 68.7 years for those with bilateral partial- or full-thickness tears. This study also showed that patients with a painful unilateral full-thickness tear had a 35.5% prevalence of an asymptomatic tear on the contralateral side. This is important because a substantial number of patients with asymptomatic tears become symptomatic after short-term follow-up (which has been associated with tear size progression) and have deterioration of shoulder function.

There are several imaging techniques that can be used to diagnose rotator cuff disease, including sonography, magnetic resonance imaging (MRI), magnetic resonance arthrography, and computed tomographic arthrography. This article will focus on the role of sonography in evaluating the patient with shoulder pain, in particular, rotator cuff disease.

Accuracy of Sonography

Sonography has become an accepted imaging technique for evaluating the patient with suspected cuff disease. It can be used to accurately diagnose and quantify full- and partial-thickness tears and recurrent tears in the postoperative shoulder, determine the tear location, and evaluate the cuff muscles for fatty degeneration. It can also be used to diagnose other cuff disorders such as tendinopathy and calcific tendinitis and noncuff pathology of the biceps tendon, acromioclavicular joint, posterior labrum (paralabral cyst), and sub-deltoid bursa.

Several studies have reported high sensitivity, specificity, and accuracy for diagnosing full- and partial-thickness tears. A meta-analysis by de Jesus et al showed that sonography and MRI were comparable in both sensitivity and specificity for diagnosing full-and partial-thickness cuff tears. It is important to accurately diagnose and characterize cuff tears for treatment planning. Sonographic findings help the orthopedic surgeon decide whether treatment should be surgical or nonsurgical; if arthroscopy is indicated, sono-graphic findings help the orthopedic surgeon counsel patients regarding surgical and functional outcomes. If a nonsurgical approach is chosen, sonography can be used to follow patients for tear size progression. It can also be used to evaluate the cuff muscles for fatty degeneration, which is an important prognostic factor regarding the patient outcome; fatty degeneration portends a poor functional outcome and places the patient at risk of a retear. Two studies have shown that there is a good correlation between sonography and MRI for assessing cuff muscle atrophy and fatty degeneration, and that the diagnostic performance between the two studies was comparable for diagnosing fatty degeneration.

Sonography has also been shown to be very sensitive for diagnosing calcific tendinitis and may be used to guide aspiration of calcific deposits. Aspiration has been shown to provide prompt and long-term pain relief at 1 year. Little has been published regarding cuff tendinopathy, although it has been described in a few textbooks. A cadaveric study comparing sonographic findings to histopathologic changes showed a significant relationship between cuff tendinopathy and thickening in 21 cadaver shoulders (N. Dahiga, MD, S. Teefey, MD, W. Middleton, MD, M. Kim, MD, and C. Hildebolt, PhD, unpublished data, 2007). The diagnosis should be considered when the cuff measures greater than 5.5 mm, based on data from a study that measured cuff thickness in 100 asymptomatic men and showed a mean thickness ± SD of 4.6 ± 0.9 mm. These authors also showed that there were no significant relationships between sex, age, and cuff thickness in the absence or presence of shoulder pain. Thus, this value can be generalized to men and women regardless of age and the presence of shoulder pain.

Sonography is very accurate for diagnosing biceps tendon subluxation, dislocation, and rupture, although it was not able to distinguish a high-grade (≥70%) partial-thickness tear from a rupture. It has low sensitivity for diagnosing tenosynovitis, tendinopathy, and low-grade partial-thickness tears.

Changes to the acromioclavicular joint such as synovitis, effusion, osteoarthritis, and osteolysis are easily diagnosed with sonography. A paralabral cyst, which is usually located in the spinoglenoid notch, can be identified with sonography and aspirated under sonographic guidance for pain relief before definitive surgery. Subdeltoid bursal disorders such as an effusion and bursitis can readily be diagnosed with sonography.

Sonographic Technique

Shoulder sonography is performed using a high-frequency linear array transducer. At our institution, the patient is seated on a rotatable stool. The radiologist stands behind the patient to scan; however, at other institutions, the radiologist sits and faces the patient. The biceps tendon is the first structure to be examined; the arm is slightly externally rotated with the forearm in a supinated position resting on the thigh. This positioning ensures optimal visualization of the bicipital groove. The tendon is initially examined in a transverse plane from the level where it emerges beneath the acromion to the musculotendinous junction. The transducer is gently rocked to maintain the normal echogenicity of the biceps tendon. The transducer is then rotated 90° to examine the tendon in a longitudinal plane. It is important to orient the ultrasound beam perpendicular to the long axis of the tendon to visualize the normal echogenic, fibrillar pattern. This process may require gently pushing the inferior aspect of the transducer against the patient’s arm to ensure that the tendon fibers are oriented perpendicular to the ultrasound beam.

The subscapularis tendon is imaged next. The patient’s arm may need to be further externally rotated to optimally visualize the tendon. The transducer is initially placed in a transverse orientation at the level of the lesser tuberosity and moved medially along the long axis of the tendon. Internal and external rotation of the arm confirms that the tendon is intact. The transducer is then turned 90° to view the tendon fibers perpendicular to their long axis. This view is useful to diagnose superior partial- or full-thickness tears.

To visualize the supraspinatus and infraspinatus tendons, the patient is asked to extend his or her arm posteriorly and place the palmar side of the hand on the superior aspect of the iliac wing with the elbow flexed and directed toward the midline of the back. When scanning the cuff tendons in their long axis, it is important to remember that the long axis of the tendons is approximately 45° between the sagittal and coronal planes. It is also important to recognize that the cuff begins within a few millimeters posterior to the intra-articular portion of the biceps tendon. This portion of the biceps tendon should be identified when scanning in the long axis to ensure that the anterior aspect of the cuff is visualized. The cuff should be evaluated from the most lateral aspect of the greater tuberosity where it inserts to as far medially as possible to ensure that more medial mid substance tears are not missed. Because the cuff assumes a convex curvilinear course as it passes over the humeral head, the transducer should be gently rocked to visualize the various portions of the cuff in a plane perpendicular to the ultrasound beam as it is moved anterior to posterior. It is also important to compress the transducer against the deltoid muscle to detect any nonretracted tears. The transducer is then turned 90° to visualize the cuff in a transverse (short-axis) orientation. This view is useful to measure the width and determine the location of a cuff tear. Next, the posterior glenohumeral joint and the posterior aspect of the infraspinatus and teres minor tendons are evaluated from a posterior approach with the patient resting his or her forearm on the thigh. To identify the glenohumeral joint and the more posterior aspect of the infraspinatus tendon, the transducer is placed immediately below the scapular spine and angled slightly inferiorly. Internal and external rotation of the arm helps better visualize the infraspinatus attachment and the posterior cartilaginous labrum.

Finally, each of the posterior cuff muscles should be evaluated in long and short axes for fatty degeneration. The transducer is first placed superior to the scapular spine to image the supraspinatus muscle and then moved inferior to the scapular spine to visualize the infraspinatus muscle. The transducer is then moved slightly more inferiorly to visualize the teres minor muscle and its short tendon, most of which attaches to the surgical neck of the humerus. To visualize the entire tendon and its muscle, the transducer should be placed at the level of the surgical neck in a sagittal orientation and moved lateral to medial along the muscle.

Figure 1: Full-thickness cuff tear in a 74-year-old woman. A, The longitudinal image shows that the cuff is retracted medially, and the torn tendon end (T) is surrounded by fluid. B, The transverse image shows the width of the tear (between cursors).

The acromioclavicular joint can be imaged in both coronal and sagittal planes but is best evaluated when the transducer is oriented along the long axis of the clavicle. This view optimizes visualization of the joint space, synovium, capsule, and bony margins of the joint.

Figure 2: Full-thickness cuff tear in a 69-year-old woman. A, The longitudinal image shows the cuff tear (between cursors). The torn tendon end is not surrounded by fluid. B, The transverse image shows the width of the tear (between cursors).

 

Sonographic Findings of Shoulder Disorders

Most cuff tears begin approximately 15 mm posterior to the intra-articular portion of the biceps tendon. There may be associated bony changes on the greater tuberosity. On sonography, a full-thickness cuff tear is characterized by a focal defect created by a variable degree of retraction between the torn tendon ends. When there is fluid between the torn tendon ends, it is easy to visualize a tear (Figure 1). In the absence of an effusion, the deltoid muscle and peribursal fat occupy the space created by the defect and oppose the overlying humeral head cartilage (Figure 2). If the subdeltoid synovial tissue is thickened and inflamed, the tissue will abut the cartilage, and on sonography, a subtle loss of the normal convexity of the cuff or flattening of the cuff will be visualized. Nonretracted tears are difficult to identify. It is important to compress the deltoid with the transducer in an attempt to show the defect. Less often, a tear will occur more medially within the mid substance of the cuff; thus, it is important to evaluate the cuff where it exits beneath the acromion to the lateral aspect of the greater tuberosity. In a patient with a massive tear, the cuff is often not visualized and is retracted beneath the acromion on longitudinal views (Figure 3). Because of the size of the tear, it is usually not possible to measure an accurate width. These cuff tears are often chronic and most commonly seen in elderly patients. Subscapularis tears are uncommon and usually occur in patients with massive cuff tears or recurrent anterior shoulder dislocation. It is important to diagnose a subscapularis tear because it may alter the surgical approach.

Figure 3: Massive full-thickness cuff tear in a 53-year-old man. A, The longitudinal image shows nonvisualization of the cuff. Only the deltoid muscle overlying the humeral head is visualized. B, The transverse image also shows absence of the cuff.

Partial-thickness tears can be more difficult to identify than full-thickness tears. These tears usually occur along the deep side of the cuff at the level of anatomic humeral neck and can be recognized as distinct hypoechoic or mixed hyperechoic and hypoechoic defects on both longitudinal and transverse views (Figure 4). It is important not to mistake anisotropy for a partial-thickness tear; anisotropy produces a much less well-defined, uniformly hypoechoic region in the deep portion of the cuff. By angling the transducer such that those fibers become perpendicular to the ultrasound beam, normal tendon fibers will be noted inserting onto the greater tuberosity. A partial-thickness tear that involves more than 50% of the substance of the cuff may be compressible with the transducer and simulate a full-thickness tear. Misdiagnosing an extensive partial-thickness tear for a full-thickness tear is usually not clinically relevant because it is often treated as if it were a full-thickness tear. Partial-thickness tears may occur on the bursal side of the cuff but are much less common; small bursal-side tears are often difficult to distinguish from small full-thickness tears because both produce a focal defect or concavity on the bursal side of the cuff. Linear tears may also occur within the substance of the cuff but are more difficult to visualize than on MRI.

Figure 4: Partial-thickness articular-side cuff tear in a 55-year-old woman. A, The longitudinal image shows a distinct hypoechoic defect in the cuff (between cursors). B, The transverse image shows the width of the tear (between cursors).

Fatty degeneration of the cuff muscles can be diagnosed as described by Strobel et al.These authors evaluated the visibility of the muscle contours, pennate pattern, and central tendon and assessed the echogenicity of the cuff muscles in comparison to the deltoid muscle to grade the degree of fatty degeneration. When fatty degeneration is severe, one or more muscles will become homogeneously hyperechoic (Figure 5). A recent study showed that fatty degeneration of the cuff muscles is closely associated with the tear size and location. The greater the size of the tear, the greater the risk of fatty degeneration, and the closer the tear begins to the intra-articular portion of the biceps tendon, the greater the risk of fatty degeneration. The mechanism for the latter may be due to disruption of the rotator cable insertion (the anterior part of the supraspinatus tendon is the site of the anterior cable insertion), resulting in greater retraction of the tendon and subsequent fatty degeneration over time.

Although little has been published on the sonographic appearance of tendinopathy, on the basis of our observations, it may be a focal or diffuse process; the cuff is typically thickened, heterogeneous, and hypoechoic (Figure 6). Calcific tendinitis may be diagnosed when echogenic foci of varying size that may or may not shadow are visualized within the substance of the tendon. The calcifications are often located at the most lateral aspect of the greater tuberosity.

 

Figure 5: Marked fatty degeneration of the supraspinatus tendon in a 70-year-old man with a full-thickness cuff tear. The longitudinal image shows a homogeneously echogenic supraspinatus muscle.

Disorders of the biceps tendon are commonly associated with rotator cuff disease and are important sources of shoulder pain. When the biceps tendon is thickened and hypoechoic, tendinopathy should be considered. Tendinopathy usually occurs in patients with large chronic cuff tears. Intrasubstance tears may also occur and appear as linear hypoechoic defects. Tenosynovitis is often associated with an effusion. A thickened tendon sheath with or without flow on color or power Doppler imaging is diagnostic of tenosynovitis (Figure 7). Tendon subluxation is considered present when the tendon partially extends above a line drawn from the lesser to the greater tuberosity and dislocated when perched or medial to the lesser tuberosity. Tendon rupture can be diagnosed when the bicipital groove is empty; however, a 70% or greater high-grade partial-thickness tear cannot be distinguished from rupture because the few remaining fibers are usually not visible on sonography.

 

Figure 6: Marked tendinopathy in a 75-year-old man. The longitudinal image shows a hypoechoic and very thickened cuff.

The subdeltoid bursa is a potential space and normally does not contain fluid. The presence of fluid is abnormal, and if there is concern for infection, sonography can be used to provide guidance for aspiration. Bursitis can be an overlooked cause of shoulder pain. It can be diagnosed if the subdeltoid bursa is thicker than the humeral head cartilage (Figure 8). Shoulder abduction with real-time observation helps distinguish the cuff from thickened bursa.

 

Figure 7: Tenosynovitis of the biceps tendon sheath in an 81-year-old woman. The transverse image shows thickening of the biceps tendon sheath. There is increased flow of the thickened synovium on color Doppler imaging.

A paralabral cyst is caused by a posterior capsulolabral avulsion or tear with subsequent leakage of fluid. It is best seen from a posterior approach; the transducer should be placed at the level of the infraspinatus muscle. These anechoic cysts typically occur in the spinoglenoid notch and may extend into the supraspinous or infraspinous fossa. It is important to evaluate the supraspinatus and infraspinatus muscles for fatty degeneration, which may occur if the suprascapular nerve (a mixed motor/sensory nerve) is compressed by the cyst.

The acromioclavicular joint may become infected or inflamed, causing the joint to distend with fluid and the capsule to bulge. The fluid is easily aspirated under sonographic guidance. A synovial cyst, which may be anechoic or contain debris on sonography, if found to communicate with the acromioclavicular joint, should prompt investigation of the rotator cuff because it is associated with a longstanding full-thickness cuff tear. Osteolysis appears as joint space widening and irregularity and erosions of the bony margins.

Figure 8: Bursitis in a 34-year-old woman. The transverse image shows marked thickening of the subdeltoid bursa (between cursors).

Conclusions

In summary, sonography is an excellent modality for diagnosing rotator cuff disease. It is preferred by patients, accurate, noninvasive, rapidly performed, and less expensive than MRI. Furthermore, it is a dynamic, global examination and can provide bilateral information. There is also the opportunity to interact with the patient and explain the results of the examination. However, it is important to recognize that the learning curve is long and steep, and results are operator dependent. It is also more difficult to visualize the entire cuff in obese patients and in patients with decreased range of motion, and evaluation of the labrum, joint capsule, ligaments, bone, and cartilage is limited. Thus, whereas sonography and MRI have comparable accuracy for diagnosing rotator cuff disease, these tests should be viewed as complementary rather than competitive. Which test to perform should be based on the clinical information sought and the inherent strengths and weaknesses of each test.

NHÂN CA LỒNG RUỘT RUỘT THỪA tại MEDIC

Appendiceal Intussusception into Cecum: Case Report, Ly Van Phai, Le Thi Quynh Nhu, Nguyen Thien Hung, Phan Thanh Hai, Medic Medical Center, Ho Chi Minh City, Viet Nam

Abstract

Appendiceal intussusception is not a common disease and is rarely diagnosed preoperatively. In our case, a 25-year-old male patient living in Ho Chi Minh City came to Medic Medical Center complaining about his epigastric abdominal pain, which lasting for 3 days. His body temperature was not high and he did not have any other symptoms. He recalled similar pain which had gone away without any treatment three months ago. Abdominal ultrasound showed abnormalities in appendix and cecum. During performing colonoscopy, we suspected appendiceal intussusception, and following computed tomography showed the images of enlarged appendix with fluid-filled lumen and signs of intussusception at the appendix base. The patient underwent an operation to remove the appendix and appendiceal intussusception was confirmed. Microscopic result was consistent with chronic appendicitis.

Intussusception of the appendix vermiformis in adults is a rare condition caused by anatomical and pathological factors such as tumors and is rarely diagnosed before surgery.

Although most appendiceal tumors are benign, tubular adenoma is an unusual lesion. Furthermore, carcinoma of the appendix is a distinctly rare phenomenon. The combination of both a carcinoma and intussusception has been regarded as extremely rare. Here, we report a case with intussusception of the appendix induced by primary appendiceal adenocarcinoma and discuss the clinical features, classification, preoperative diagnosis and therapy of this condition together with a review of the literature.

 

 

DISCUSSION

Intussusception of the appendix is an uncommon pathological condition. The incidence of invagination of the appendix is 0.01% in a large autopsy series. The etiology of appendiceal intussusception has been proposed by Fink et al. to be divided into anatomical and pathological causes. Anatomical variations include a fetal-type cecum, a wide appendicular lumen and a thin, mobile appendix. Reported pathological conditions include worms, endometrial implants and tumors. Various classifications of appendiceal intussusception have been attempted. Forshall divided cases into a primary type and a secondary or compound type. Langsam et al. classified the disorder into four types according to the relationship of the intussusceptum and intussuscipiens. In our case, the appendiceal tumor as a leading point seemed to have induced the complete appendiceal intussusception.

Preoperative diagnosis of intussusceptions of the appendix is often difficult because it is a rare clinical entity; only a few cases can be diagnosed by barium enema and colonoscopy. Many cases have been diagnosed as filling defects or polypoid tumors of the cecum. Careful endoscopic examination, identifying the appendiceal orifice, should be required in the case of cecal polyp. When differential diagnosis is difficult, computed tomography or abdominal ultrasound is more useful. A definite finding of intussusception of the appendix in CT is the invaginated appendix in the cecal cavity.

Tumors of the appendix are uncommon; also, most tumors are benign. Adenoma of the appendix is also a rare condition. Only 50 cases of appendiceal adenoma were reported among 30 000 appendectomies. Moreover, primary adenocarcinoma is a very rare entity, which in most cases arises from a pre-existing adenoma. Ohno et al. first reported appendiceal intussusception induced by tubulovillous adenoma with carcinoma in situ similar to our case; the combination of both a carcinoma in adenoma and intussusception has been regarded as extremely rare.

Treatment of appendiceal intussusception is mainly surgical. The procedure varies from reduction of intussusception with appendectomy to right hemicolectomy. A right hemicolectomy or ileocecal resection with lymph node dissection should be performed when carcinoma is diagnosed preoperatively or during surgery. In the last decade, laparoscopic procedures have been applied to the treatment of almost all colonic diseases, including both benign and malignant lesions. As Schmidt et al. reported laparoscopic management of appendiceal intussusception, laparoscopic procedures will be more useful as a minimally invasive treatment.

The clinical manifestation of appendiceal intussusception with primary appendiceal tumor resembles a large cecal polyp with a wide stalk, but its treatment is completely different. Endoscopic removal should be performed carefully in cases of polypoid lesions in the cecum, taking into consideration the possibility of an invaginated appendix. Failure to recognize this condition may result in unexpected complications such as consequent peritonitis.

 

VIÊM RUỘT THỪA CẤP Ở TRẺ EM: NÊN KHÁM SIÊU ÂM TRƯỚC TIÊN

Sonography is widely available, can be performed at the bedside, involves a short acquisition time, does not use ionizing radiation, is relatively inexpensive, and may show evidence of other causes of abdominal pain. It is particularly useful in evaluating young women, in whom the radiation dose to the reproductive organs should be minimized and for whom it is important to exclude ovarian and uterine conditions that might mimic appendicitis. There have been multiple studies evaluating the value of sonography in the evaluation of appendicitis, showing varying sensitivity, specificity, and accuracy. However, a recent study by Pacharn et al found that sonography for acute appendicitis had a negative predictive value of 95%, making it an excellent screening tool in the evaluation of acute appendicitis. Goldin et al suggested that standardizing the technique and criteria will decrease variability in the diagnostic accuracy of sonography across institutions.

Technique

The standard sonographic evaluation of the abdomen based on the American Institute of Ultrasound in Medicine practice guideline includes imaging of the appendix. A complete abdominal sonographic examination does not need to be performed in the evaluation of acute appendicitis.

However, because the appendix is not always located in the right lower quadrant and an abscess could be present, imaging should include not only the right lower quadrant but also the pelvis and left lower quadrant. A survey of the abdomen for free fluid or bowel thickening elsewhere is also helpful, especially in cases of suspected perforation.

At the start of the examination, it is helpful to ask the patient to point to the site of maximal tenderness and begin scanning in this location. Using a high-resolution linear transducer, the abdomen should be compressed while scanning, which moves bowel gas out of the field of view. This compression sonography is performed with an empty bladder. The most reliable way to identify the appendix is to find the ascending colon, follow the colon proximally to the cecum, and then find the appendix extending off the cecum.

If the appendix cannot be seen in the supine position, it may be helpful to place the patient in the left lateral decubitus position to cause a retrocecal appendix to be better seen.

Scanning with a full bladder may also be helpful because it can better delineate a deep pelvic appendix that might be obscured by overlying bowel.

The complete appendix should be visualized, including the tip. The maximal outer wall diameter should be measured, and the wall thickness should be measured along the course of the appendix. The normal maximal outer wall diameter of the appendix is less than 6 mm, and the mural thickness is less than 2 mm (Figure 1A). Compression of the appendix should be performed, with documentation of the appearance of the appendix during compression. A normal appendix compresses (Figure 1B). Secondary signs such as free fluid, a fecalith, and hyperechoic surrounding fat should be documented. Doppler imaging is helpful to evaluate for hyperemia; however, a necrotic appendix will have decreased or no blood flow. Video clips should be obtained to show normal peristalsis unless the physician is present during the scan. If an abscess is suspected, a lower- frequency curved array transducer may be used for a larger field of view and deeper penetration.

It is not always necessary to identify a normal appendix to consider the findings negative.  If there are no secondary signs as mentioned above, and clinical suspicion is moderately low for appendicitis, many institutions stop the evaluation and consider the sonographic findings negative for appendicitis.

In the setting of acute appendicitis, the appendix is noncompressible, and the maximal outer wall diameter is greater than 6 mm (Figure 2). An appendicolith may be present, helping the diagnosis (Figure 3); however, an appendicolith can be present without acute appendicitis, and the presence of an appendicolith does not confirm acute appendicitis.

There may also be secondary signs of inflammation, such as hyperechoic surrounding fat, free fluid, or an abscess (Figure 4). The wall may be hyperemic (Figure 5). Enlarged nodes can also be seen in the right lower quadrant, but this finding is nonspecific and can also be seen in patients without appendicitis. The surrounding bowel may be dilated with loss of normal peristalsis due to ileus.

Conclusions

Right lower quadrant sonography, when performed using rigorous technique and criteria for diagnosis, is an excellent screening tool for acute appendicitis. This examination is quick and painless and does not involve the use of ionizing radiation. Although the sensitivity, specificity, and accuracy of sonography vary greatly in studies evaluating the imaging diagnosis of acute appendicitis, it should be the first imaging modality when there is clinical concern for acute appendicitis. Only if the examination is equivocal or if the appendix cannot be identified should other imaging modalities such as CT be considered.

J Ultrasound Med 2012; 31:1153–1157 | 0278-4297 |www.aium.org

Valve of Gerlach/appendiceal orifice Joseph von Gerlach Joseph von Gerlach (1820-1896)

Appendiceal orifice (arrow) and water filled cecum.

Joseph von Gerlach (April 3, 1820 – December 17, 1896) was a German professor of anatomy at the University of Erlangen. He was a native of Mainz, Rhineland-Palatinate. Gerlach was a pioneer of histological staining and anatomical micrography. In 1858 Gerlach introduced carmine mixed with gelatin as an histological stain.[1] Along with Camillo Golgi, he was a major proponent of the theory that the brain's nervous system consisted of processes of contiguous cells fused to create a massive meshed network. Gerlach summed up his theory by stating: the finest divisions of the protoplasmic processes ultimately take part in the formation of the fine nerve fibre network which I consider to be an essential constituent of the gray matter of the spinal cord. The divisions are none other than the beginnings of this nerve fibre net. The cells of the gray matter are therefore doubly connected by means the nerve process which becomes the axis fibre and through the finest branches of the protoplasmic processes which become a part of the fine nerve fibre net of the gray matter. The reticular theory predominated until the 1890s when Ramon y Cajal brought forth his neuron doctrine of synaptic junctions, which in essence replaced the reticular theory. Gerlach was one of the first physicians to use photomicrography for medical research. In 1863 he published a handbook titled Die Photographie als Hilfsmittel mikroskopischer Forschung (Engl. "Photography as a tool in microscopic science") in which he discusses the practical and technological aspects of microscopic photography. The eponymous "Gerlach's valve" (valvula processus vermiformis) is named after him. This anatomical structure is a fold of membrane sometimes found at the opening of the vermiform appendix.[2] In his article Ueber das Hautathmen[3] (Engl. "On skin respiration") he was the first to show that human skin uses oxygen from ambient air.

COMPARISON SWE to STRAIN ELASTOGRAPHY for THYROID NODULES

Abstract

Although elastography can enhance the differential diagnosis of thyroid nodules, its diagnostic performance is not ideal at present. Further improvements in the technique and creation of robust diagnostic criteria are necessary. The purpose of this study was to compare the usefulness of strain elastography and a new generation of elasticity imaging called supersonic shear wave elastography (SSWE) in differential evaluation of thyroid nodules. Six thyroid nodules in 4 patients were studied. SSWE yielded 1 true-positive and 5 true-negative results. Strain elastography yielded 5 false-positive results and 1 false-negative result. A novel finding appreciated with SSWE, were punctate foci of increased stiffness corresponding to microcalcifications in 4 nodules, some not visible on B-mode ultrasound, as opposed to soft, colloid-inspissated areas visible on B-mode ultrasound in 2 nodules. This preliminary paper indicates that SSWE may outperform strain elastography in differentiation of thyroid nodules with regard to their stiffness. SSWE showed the possibility of differentiation of high echogenic foci into microcalcifications and inspissated colloid, adding a new dimension to thyroid elastography. Further multicenter large-scale studies of thyroid nodules evaluating different elastographic methods are warranted.

Methods

During a few weeks trial time in 2010, four consecutive patients with single thyroid nodule (n = 1) and nodular goiter (n = 3) were evaluated. Approval for this study was obtained from the Ethics Committee of the Medical University of Warsaw, and all patients provided informed consent.

The Bmode and power Doppler ultrasound of whole thyroid and neck lymph nodes was performed. Six dominant thyroid nodules (in regard to B-mode and power Doppler ultrasound features) were evaluated with shear wave and strain elastography qualitatively and quantitatively as well as some with contrast-enhanced ultrasound (Sonovue (Bracco)). The examinations were performed with following scanner: AiXplorer (Supersonic Imagine Inc. France)—SSWE, Aplio XG (Toshiba, Japan)—strain elastography, Technos (Esaote, Italy)—contrast-enhanced ultrasound, with linear high-resolution transducers: 15–4MHz, 18–7MHz, and, 8–3MHz respectively. For strain elastography, we adopted qualitative scale of Rubaltelli et al. with threshold score of 2/3 and quantitative scale of Cantisani et al. with threshold thyroid tissue/nodule strain ratio of 2 measured with Elasto-Q (Toshiba). For shear wave elastography, we adopted quantitative scale of Sebag et al. with the threshold stiffness (mean elastic modulus) of thyroid nodule of 65 kPa.

The final diagnosis was based on clinical evaluation, multiple FNB, 1 year followup, or surgery.

Discussion

Supersonic shear weave elastography consists of the generation of remote radiation force by focused ultrasonic beams, the so-called “pushing beams,” a patented technology called “Sonic Touch”. Using Sonic Touch, ultrasound beams are successively focused at different depth in tissues. The source is moved at a speed that is higher than the speed of the shear waves that are generated. In this supersonic regime, shear waves are coherently summed in a “Mach cone” shape, which increases their amplitude and improves their propagation distance. For a fixed acoustic power at a given location, Sonic Touch increases shear wave generation efficiency by a factor of 4 to 8 compared to a nonsupersonic source. After generation of this shear wave, an ultrafast echographic imaging sequence is performed to acquire successive raw radiofrequency dots at a very high-frame rate (up to 20,000 frames per second). Based on Young’s modulus formula, the assessment of tissue elasticity can be derived from shear wave propagation speed. A color-coded image is displayed, which shows softer tissue in blue and stiffer tissue in red. Quantitative information is delivered; elasticity is expressed in kilo-Pascal (kPa).

This preliminary paper based on small number of cases indicates that SSWE indicated correctly thyroid nodules suspicious for cancer in contrast to strain elastography. False positives on strain elastography could be due to liquid or degenerative content of nodules.

However, imaging with SSWE, as a sensitive method of evaluation of stiffness of human tissue, the operator should be aware of physiological processes influencing the elasticity and easily apply a few rules to avoid artifacts (Figures 4, 5 and 6). Among well-known artifacts on SSWE that should be mentioned is the one that can be encountered in any region when the SSWE can be applied: the increased stiffness of the structures under externally applied pressure (Figures 4 and 5) that can be due to nonlinear elastic effects, well explained by theory.

Another artifact that can be encountered in thyroid SSWE is one of increased stiffness in the isthmus of the thyroid due to trachea (Figure 6). It can be avoided with imaging in paracoronal plane of the nodule that does not incorporate the trachea. However, it is important to state that these artifacts when properly interpreted do not hinder the accurate diagnosis.

Supersonic shear wave elastography may add a new dimension to ultrasound evaluation of thyroid nodules in several ways, for example:

(a) improve general performance in elasticity differentiation of thyroid nodules over strain elastography due to its high reproducibility, independence of examiners skill and numeral scale of elasticity measurement in kPa;

(b) overcome the limitations of strain elastography=

  (i) nodules with liquid components or with degenerative changes;

  (ii) small nodules (very good spatial resolution of the technique);

  (iii) large nodules (possibility of subsequent determination of stiff regions even  of large nodules, without the need of visualizing the whole nodule on one image);

  (iv) multinodular goiter with no or scarce normal thyroid tissue as a reference;

(c) differentiation between soft-inspissated colloid and stiff microcalcifications;

(d) visualization of microcalcifications, even not visualized on B-mode imaging (may increase sensitivity and decrease specificity of thyroid cancer diagnosis);

(e) introduction of three-dimensional elastographic images to routine clinical practice and to national thyroid cancer databases, as this technique is

already available and enables rapid acquisition of 3D ultrasound and elastographic data. This would devoid diagnostic process and data archiving of image selection bias attributable to 2D ultrasound examination.

Further multicenter large scale studies of thyroid nodules evaluating different elastographic methods are warranted, including (a) investigation of developmental models of diseases that link biomechanical properties (elastography findings) with genetic, cellular, biochemical, and gross pathological changes; (b) comparison of accuracy of different elastographic methods; (c) establishment of optimal diagnostic elastographic criteria; (d) establishment of limitations of different elastographic methods in relation to evaluation of thyroid pathology.

PHÂN BIỆT ÁPXE và VIÊM MÔ TẾ BÀO - ÁPXE LẠNH

Abscess Evaluation

Brian Euerle, MD, RDMS

I. Introduction and Indications

Abscess and cellulitis are two of the most common soft-tissue infections seen in patients treated in emergency departments. Although they sometimes occur together, they are different disease processes requiring different treatments. An abscess is treated with incision and drainage and may not require antibiotics; cellulitis is treated with antibiotics alone.

It can be difficult to differentiate cellulitis from abscess based only on history and physical examination findings. Both processes may generally be characterized by warmth, erythema, tenderness, swelling, and induration. In some patients, an abscess is clearly evident because of obvious fluctuance and copious purulent drainage; however, this distinct presentation is not seen in the majority of cases. Because of the difficulty in diagnosis, the emergency physician might decide upon an inappropriate treatment, resulting in one of two possible errors. Incision and drainage might not be done in a patient with an abscess, or incision and drainage could be performed on a patient who has cellulitis but no abscess. Increased pain and poor patient outcome can result from either one of these errors.

Many researchers, including emergency physicians, have reported on the utility of ultrasound in the evaluation of abscesses and cellulitis. One group of emergency physicians found that soft-tissue ultrasound changed the management strategy for approximately half of their patients and concluded that ultrasound was useful because it could detect occult abscesses and avoid invasive procedures.

Ultrasound also allows many procedures to be done with greater safety. In the case of abscess drainage, ultrasound can locate adjacent structures such as large blood vessels and nerves that need to be avoided during the drainage procedure.

The use of bedside ultrasound can also help determine the treatment of a specific abscess based on its size and depth.
If an abscess is very small (smaller than 1 cm), the physician might choose treatment with antibiotics and warm compresses rather than incision and drainage.

Although the majority of abscesses are treated with incision and drainage, in certain cases, usually because of cosmesis, treatment with needle aspiration and antibiotics may be an option. Ozseker and colleagues found that ultrasound-guided aspiration and irrigation of breast abscesses was preferred to surgical drainage for abscesses with a diameter less than 3 cm. Ultrasound provides dynamic real-time guidance for needle aspiration, resulting in increased success.

II. Anatomy

The structures that are imaged in bedside ultrasound for abscess evaluation are primarily the skin, subcutaneous tissue, and fascia. The skin consists of two layers: the superficial epidermis and the deeper, thicker dermis. Subcutaneous tissue, located beneath the dermis, consists of connective tissue septa and fat lobules. Fascia, a deeper structure, is a dense, fibrous membrane.

III. Scanning Technique, Normal Findings and Common Variants

Equipment
It is important to select an appropriate transducer when using bedside ultrasound for abscess evaluation. Because most subcutaneous abscesses are relatively superficial, a high-frequency (7-12 MHz) linear array transducer is most useful. At times a deeper abscess may be beyond the range of the linear transducer and a lower frequency transducer must be used. In this situation, a lower frequency linear array transducer may be helpful. If this type of transducer is not available, a curvilinear transducer may be used.
Evaluation for peritonsillar abscess is a specialized application in which a high frequency intracavitary probe can be used.

Many emergency practitioners are familiar with the use of color Doppler ultrasound and this can be useful in abscess evaluation. One way in which Doppler can be helpful is by identifying large blood vessels that are adjacent to an abscess. Color Doppler can also be helpful in the evaluation of groin masses because it can help differentiate an abscess from a pseudoaneurysm. Power Doppler is a more advanced technique that is able to detect low velocity blood flow and movement. This can be used in abscess evaluation because it can identify hyperemia in the walls of abscesses and the surrounding tissues.

Scanning Technique

It is helpful to begin scanning a short distance away from the area of interest to gain an appreciation of the appearance of the normal, uninvolved anatomy. It may also be helpful to view the contralateral side of the patient’s body to obtain information about the normal appearance of structures.

Next, slide the probe over the extent of the abscess or cellulitis, maintaining the same orientation. Once the area has been visualized appropriately, rotate the transducer 90 degrees and repeat the process. If an abscess is present, place a gloved finger of the nondominant hand on the point of maximal fluctuance or “point” of the abscess. Then slide the transducer so that its mid-point is located against the finger. This can help you correlate the image on the screen with the anatomy and help plan the site of the incision. Body markings can also be used to indicate the extent of the abscess or location of the incision.

Once the presence of an abscess is confirmed, set the ultrasound probe aside and proceed with the incision and drainage. Another option is to incise the area while observing in real time under ultrasound. This technique may be helpful for deep or small collections, but it generally is not necessary.

It may be helpful to repeat the ultrasound examination after incision and drainage to assess the success of the procedure and locate undrained collections of purulence.

Normal Findings

With the equipment that is typically used for bedside ultrasonography, the epidermis and dermis cannot be differentiated. They appear together as a thin, hyperechoic layer. The subcutaneous layer appears hypoechoic on ultrasound, with two components: hypoechoic fat interspersed with hyperechoic linear echoes running mostly parallel to the skin, which represent connective tissue septa (Figure 1). Veins and nerves may be visualized within the subcutaneous layer.

Fascia appears as a linear hyperechoic layer. Its thickness may vary depending on the location.

Figure 1: Normal skin, subcutaneous tissue, and fascia.

IV. Pathology

On ultrasound an abscess is a spherical or oblong shaped structure that is largely anechoic or hypoechoic (Figure 2). However, as opposed to a simple cyst that will be uniformly anechoic throughout, an abscess will contain hyperechoic debris. This feature can be used to differentiate an abscess from a cyst. The walls of the abscess cavity may be distinct and hyperechoic, or may have a ragged appearance and intermix with the adjacent tissue. Because of the anechoic nature of the abscess, posterior acoustic enhancement may be seen. Dynamic scanning, achieved with gentle compression of the probe, may cause the contents of the abscess to swirl, which can be diagnostic of an abscess. Hyperechoic foci of air may be seen in necrotizing fasciitis.

Figure 2: Abscess containing hyperechoic debris.

The ultrasound appearance of cellulitis may vary depending on the stage and severity. The initial appearance may be generalized swelling and increased echogenicity of the skin and subcutaneous tissues. As cellulitis progresses and the amount of subcutaneous fluid increases, hyperechoic fat lobules become separated by hypechoic fluid-filled areas. This later stage of cellulitis is most typical and has been described as having a cobblestone appearance (Figure 3)

Figure 3: Cobblestone appearance of advanced cellulitis.

V. Pearls and Pitfalls Abscess and cellulitis are two common soft-tissue infections that can appear similar on physical examination. Bedside ultrasound can be very helpful in differentiating cellulitis from abscess. Ultrasound is effective at identifying occult abscesses in emergency department patients initially suspected of having cellulitis. On ultrasound imaging, an abscess appears as a spherical or oblong anechoic or hypoechoic collection containing hyperchoic debris.

Cold Abscess

from www.e-radiography.net

Definition
A cold abscess is an abscess that commonly accompanies tuberculosis. It develops so slowly that there is little inflammation, and it becomes painful only when there is pressure on the surrounding area. This type of abscess may appear anywhere on the body, but it is most commonly found on the spine, hips, lymph nodes, or in the genital region.

Radiographic Appearance
Radiologicaly there may be erosion of bone local to the abscess, or evidence of organ compression.
A sinogram will demonstrate the extent of the abscess.

Plain radiographs occasionally show a blurring or indistinctness of the lateral margins of the psoas muscle but, in general, are not as helpful as other techniques. Ultrasonography is useful in showing enlarged psoas muscle with hypoechogenic masses, however it is not as accurate as a CT scan in showing the abscess. MRI is advantageous because multiple processes can be evaluated.

Pathology
Although primary psoas abscess is very rare in children of "developed" countries, it is not rare in tropic and sub-tropical "third world" countries with poor socioeconomic conditions. Staphylococcus aureus is the most frequent type of infection seen in these environments, with almost all children presenting with the triad of pyrexia, flank pain and hip symptoms.
Psoas abscess can be a secondary problem associated with tuberculous spondylitis or in relation to inflammatory bowel disease (1). More recently, in the United States, psoas abscesses have been seen secondary to transperitoneal low-velocity gunshot wounds to the spine (3), or gastrointestinal or genitourinary trauma (2). Primary psoas abscess can be seen in patients with sickle cell disease, intravenous drug users, immunocompromised individuals or individuals positive for HIV.

Treatment:
Drainage of the abscess by CT-guided percutaneous catheter has been recommended by some, while surgical drainage is recommended by others, especially when percutaneous catheter drainage is not successful, followed by appropriate antibiotic therapy.

NHÂN CA CYSTIC LYMPHANGIOMA CỦA ĐUÔI TUỴ TẠI MEDIC

Xem HUGE CYSTIC LYMPHANGIOMA of PANCREAS tại MEDIC.

Discussion of Pancreatic Lymphangioma

from http://www.tmuh.org.tw
Background

- Neoplasms, hamartomas, or lymphangiectasias ?

- Malformations arising from sequestered lymphatic channels

or

- Acquired lesions due to obstruction caused by fibrosis of lymph channels.

- Developmental anomaly, distension of sequestered lymphatic channels within primitive mesenchyme rather than a true neoplasm.

- Most common sites: head, neck, and axilla.

- Only 5 % at mesentery, omentum, mesocolon, and retroperitoneum.

- Pancreatic lymphangiomas (1%) occur predominantly in women (F/M: 2:1). Average age : 25.6 years.

Classification

- Cystic, capillary, and cavernous.

- Only cystic and cavernous types have been reported in the pancreas

- Considered to be of pancreatic origin :

• in the pancreatic parenchyma,
• adjacent to the pancreas,
• connected to the organ by a pedicle

Clinical Presentations

- Abdominal pain

- Nausea

- Vomiting

- Palpable mass

- Silent, incidental finding.

Morbidity/ Mortality

- No risk of malignant transformation.

- May local invasion.

- Strong tendency for local recurrence unless they are completely excised.

Pathology 

Gross

- Soft, multiloculated cystic masses.

- Content: serous, serosanguinous, or lymphatic fluid.

Histology

- Dilated lymphatic channels, separated by thin septa.

- Cystic spaces lining:  flattened or cuboidal endothelial cells.

- Aggregates of lymphocytes.

- The septa and walls: smooth muscle fascicles and collagenous connective

tissue.

Image -- Sonography character

- Anechoic or hypoechoic

- Fluid-filled

- Multiseptated mass in the pancreatic region.

Image -- CT character

- Well-circumscribed

- Homogeneous cystic masses in or adjacent to the pancreas.

- Septums and thin walls may enhance after IV contrast injection.

Image -- MRI character

- Hypointense on T1-weighted image

- Hyperintense on T2-weighted image.

- Not provide new information.

Diagnosis

- History

- Imaging: sono, CT, MRI

- Fine-needle aspiration cytology.

- Definite diagnosis: pathology report.

Treatment

- No proven medical care for lymphangiomas exists.

- Treatment of choice: complete surgical excision.

Prognosis

- Lymphangiomas are benign hamartomatous malformations instead of true neoplasms.

- Locally invasion may occur.

- The prognosis is excellent.