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General Ultrasound
US in Biliary Diseases
Seoul National University Hospital The role of imaging in biliary diseases is detection, characterization of a lesion, diagnosis of biliary obstruction including determination of the obstruction level, and differentiation of benign from malignant causes, and preoperative staging of malignancies for resectability. US plays an important role in screening exam due to its several advantages. They include real-time evaluation, safety, flexibility, portability, and no radiation hazard or iodine toxicity. But, US has limitation in preoperative staging of malignancies. Recently, contrast-enhanced US technique is rapidly developing and might be useful in staging, but, is still in the beginning stage. Nevertheless, real-time US is a method of choice in detecting and diagnosing gallstones and common duct stones. And also useful in gallbladder cancer, and CBD cancer. In this talk, I will give you a brief introduction about US anatomy and techniques, present anomaly, stone disease and related conditions, and biliary neoplasms including gallbladder and bile duct cancer. Recent Advances in US Technology
Department of Radiology, Seoul National University Hospital Technical improvements have made profound changes in diagnostic ultrasound imaging. New technologies are dedicated toward several directions; improved contrast and spatial resolution, improved lesion detection and differentiation, extended field-of-view, and 3D or 4D imaging. Improvement of contrast and spatial resolution has been made in all US machine components such as US probe and software. They include matrix array transducers, coded pulse technique, tissue harmonic imaging, spatial compounding technique, and speckle reduction imaging. For the improvement of lesion differentiation, contrast-enhanced US and elastography have been developed. Many of these technologies can be used alone as well as together. This lecture will attempt to update the abdominal radiologists on the clinical applications of these newer technologies. Proceeding of 2010 Annual Convention TSUM General Ultrasound
Differential Diagnosis of Cystic Pancreatic Lesions:
Special Emphasis on Serous Cystic Neoplasms
Seoul National University Hospital By virtue of rapid advancements in imaging techniques such as CT or MRI and their increased access and use, cystic pancreatic lesions are being recognized with increasing frequency and have become a common finding in clinical practice. At least 1% of hospitalized patients at major medical centers have a pancreatic cyst upon cross-sectional imaging, more than half of which are neoplastic. The first and most important diagnostic strategy for accurate characterization of pancreatic cystic neoplasms is to differentiate non-mucinous type cystic tumors such as serous cystadenomas (SCAs) from mucinous types of tumors, including mucinous cystic neoplasms (MCNs) or intraductal papillary mucinous neoplasms (IPMNs). The reason is that SCAs should be managed as a benign disease while mucinous lesions are potentially or overtly malignant lesions. In such cases, surgery is generally the treatment of choice. Serous cystic neoplasms (SCNs) account for approximately 20% of all cystic tumors of the pancreas. Microscopically, SCNs are characterized by cysts lined by glycogen-rich, cuboidal cells, filled with clear and thin serous fluid with richly-vascular collagenous or hyalinized stroma. In the past, SCNs previously referred to “ microcystic adenomas ” while mucinous cystadenomas to “ macrocystic adenomas. ” Therefore, the characteristic imaging feature of SCNs is a honeycomb pattern with central scar or central calcification, the typical imaging findings of serous microcystic adenomas. However, with rapid advancements and increased use in imaging techniques as well as with recent increased knowledge of pancreatic SCNs, various morphologic appearances of SCNs have been widely encountered in routine clinical practice and many investigations have clarified the morphologic variety of SCNs and their pathologic backgrounds. Currently, SCNs are further categorized into 5 different subtypes according to their macroscopic appearances: serous microcystic adenomas, the typical and traditional SCN, serous oligocystic adenoma, von Hippel Lindau-associated cystic neoplasm, solid serous adenoma, and serous cystadenocarcinoma. In line with the pathologic variability, a wide spectrum of radiologic manifestations of pancreatic SCNs, leading to diagnostic challenges to radiologists has also been known to occur; however little attention has been given to their variability on radiologic findings nor has systematic investigation in relation to this issue been performed. Recently, we realized that SCNs can have variable US and CT appearances from compactly solid hypervascular to clearly unilocular cystic pattern, reflecting a varied macroscopic morphology. Only one-third of the SCNs show traditional typical imaging features whereas a considerable proportion (two-thirds) of SCNs showed atypical appearances. In atypical cases, a lobulating outer margin and the absence of diffuse or downstream main pancreatic duct dilatation may be the helpful differential features of SCNs from their mucinous counterparts. In this lecture, I will discuss the typical and atypical imaging features of serous cystic neoplasms. Proceeding of 2010 Annual Convention TSUM General Ultrasound
Common Artifacts in Abdominal Ultrasound
Department of Radiology Taichung Veteran General Hospital Although ultrasound machine have a tremendous improvement in recent decades, it is still not a perfect science and artifacts persist on image. Diagnostic ultrasound is useful for detection of diseases, but unable to recognize acoustic artifacts can cause serious misdiagnoses. Sonographic systems assign depth based on the time interval of round-trip echo travel and assume a straight line and singular path from transducer to reflector and reflector to transducer. The same speed of sound is assumed in all tissues for the purposes of spatial assignment. The ultrasound machine does not know whether that packet of sound energy was reflected, was refracted or otherwise took a different pathway on its way back, or both. It also does not know whether a sound-attenuating or sound-enhancing structure has been placed between the transducer and the interface. The artifact may be a misrepresentation of the location of the original interface or of the signal intensity of the echo from that interface. The most artifacts usually are not even noticeable and are frequently superimposed on partial or the entire image that are not clinically important but some artifacts can make misinterpretation. The common artifacts in abdominal ultrasound include reverberation, refraction, attenuation, shadowing, mirror image, enhancement, side lobe, beam width, comet tail, ring-down and speed displacement in daily practice. Understanding the physical explanation of artifacts will be able to know tissue composition by unavoidable artifacts and will be able to adjust potentially correctable US artifacts to improve the image quality, that can increase the power of the diagnostic interpretation. However, it is important that sonographers and sonologist should understand and recognize artifacts to prevent significant errors in diagnosis. Proceeding of 2010 Annual Convention TSUM General Ultrasound
Challenges and Pitfalls in Abdominal Ultrasonography:
Gastrointestinal Tracts
Department of Radiology, Taichung Veterans General Hospital With the improvement of resolution & introduction of color Doppler, transabdominal ultrasonography (TAUS) has played more important role in the diagnosis of gastrointestinal tract (GIT) disorders. Many different disease entities can be demonstrated by TAUS, such as acute appendicitis, intestinal obstruction including afferent loop syndrome, inflammatory bowel disease, intussusception, intramural duodenal hematoma, hypertrophic pyloric stenosis, and gastrointestinal tumors. However, the majority of sonographers and ultrasonists are not familiar with the normal anatomy of the GIT and always skip the GIT in abdominal ultrasonography. The most common problems are owing to gas blockade, technical limitations, perceptive errors and mis-interpretation by physicians or radiologists. In our daily practice, we encountered many cases of pitfall or challengeable conditions of abdominal ultrasonography, such as unusual location of appendicitis, clinically unsuspected colon or gastric cancer, gas-forming abdominal abscess, pneumoperitoneum, and pseudotumor due to aggregation of intestinal loops. The detail imaging findings will be presented at the meeting. The Challenges & Pitfalls of Ultrasonography in
Retroperitoneal Space & Lymphadenopathy
Kaohsiung Veterans General Hospital The retroperitoneum is the space behind the abdominal cavity extending from the posterior peritoneum to the spinal column and the back muscles. It extends superiorly from the diaphragm and inferiorly to the levator muscles of the pelvis. The retroperitoneum is divided into the anterior pararenal space (GI space), the perirenal space (GU space) and posterior pararenal space (nothing space). Ultrasonography has inherent limitations for imaging the retroperitoneum because far distance with probe and interference of bowel gas except kidneys, main trunk of aorta and vena cava or the lesion is huge. Even though, the lymphatic chains including paraaortic, paracaval, interaortocaval, preaortic and precaval regions (including parietal and visceral groups) are necessary to survey if any malignancy or lymphoma were suspected. The abnormal lymphadenopathy will present as hypoechoic structures without hilar fat. Early clinical manifestations are nonspecific, thus allowing pathologic processes to become relatively advanced before producing symptoms. Retroperitoneal disease processes often present as a mass. The differential diagnosis of a solitary hypoechoic lesion should include neurogenic tumor, sarcoma, lymphagioma, hemangiopericytoma, teratoma, calcifying fibrous tumor or other rare tumors. Fluid collection at the retroperitoneum should differentiate with pseudocyst, anasarsa, urinoma, hematoma, abscess formation or bowel perforation. Gas collection is not as simple identify as KUB. Retroperitoneal fibrosis is not as easy to diagnosis as CT or MRI. However, Experienced sonologist can interpreter beyond the inherent limitations. Proceeding of 2010 Annual Convention TSUM General Ultrasound
Challenges and Pitfalls in Abdominal US - Pediatric Abdomen
Department of Pediatrics, Mackay Memorial Hospital Abdominal ultrasound examination is now one of the most important image diagnoses for the pediatric abdominal disease, especially in detecting abdominal mass and solid organ disease. However, the diagnosis may challenge to the examiner in hollow organ disease, for example, acute intestinal obstruction. For good interpretation, the examiner and reporter must get a clear understanding of normal anatomy, basic approaches to scanning, and the many pitfalls in interpretation inherent in the method. Gas, fluid and mucus patterns are the 3 basic presentations in GI imaging and are usually misinterpreted by an un-experienced examiner. For example, a simple colonic dilatation presented as single doughnut configuration at RLQ may be misdiagnosed as intussusceptions in infancy. Furthermore, a cystic lesion in abdomen may difficult to interpret as mesenteric cyst, duplication cyst or ovarian cyst, if the patient is a girl. Another challenge is the diagnosis of acute appendicitis in absence of abscess formation. Pitfalls may be derived from improper adjustment and selection of the improper probe in adult patients. In children, Irritable crying during examination and/ or diffuse abdominal gaseousness increase the difficulty of examination and diagnosis. Although gaseousness is usually seen, it is not useful to administrate gascon before examination. The examiner can do lateral approach to dodge the abdominal gas. Sometimes, the underlying lesions may be easily seen after drinking water during the exam. Differential diagnosis and potential errors will be discussed during the lecture. Pancreas: Solid Lesions
National Cheng Kung University Hospital Ultrasound is the primary imaging modality used in screening patients with jaundice. Sonography can usually identify pancreatic tumor that obstructs the bile duct and may also detect a pancreatic mass in a patient scanned for abdominal pain. Computed tomography (CT) is generally superior to sonography because it routinely images the entire pancreas. Sonography is also good when the entire pancreas can be imaged and is often useful in characterizing abnormalities noted on CT, determining whether a lesion is solid or cystic. Occasionally, sonography may demarcate pancreatic masses better than contrast enhanced CT. However, the entire pancreas can be visualized in less than 50% of patients even with optimal equipment and scanning technique. Pancreatic carcinoma is the most common pancreatic neoplasm and represents 80-90% of all pancreatic tumors. Pancreatic carcinoma typically presents as a poorly-defined, homogenous/ heterogenous, hypoechoic mass in the pancreas with dilatation of the main pancreatic duct on ultrasound images. Neuroendocrine tumor, lymphoma and metastases are other possibility of solid pancreatic neoplasm. Some benign pancreatic solid lesions may also have similar imaging findings and may be indistinguishable from pancreatic carcinoma. The etiologies of these tumor-like lesions include inflammatory/ infectious diseases, congenital anomaly, and lymphoproliferative processes. Despite the presence of many known characteristics of these solid pancreatic lesions, the differential diagnosis could be difficult. Clinical information should be helpful in making a diagnosis, but the histopathology study remains the gold standard for elucidating the nature of the solid lesions in the pancreas. Proceeding of 2010 Annual Convention TSUM General Ultrasound
Great Vessels and Mesentery
Ultrasonography (US) of abdominal great vessels and mesentery is a challenge for ultrasound examiners, especially when dealing with obese or ileus patients. In general, patients are requested to faste for at least 8 hours prior to examination to reduce the disturbance of gas in stomach or bowel loops. Abdominal great vessels include abdominal aorta, and its major branches such as celiac trunk, superior mesenteric artery (SMA), bilateral main renal arteries and bilateral iliac arteries, and inferior vena cava (IVC), and its tributaries such as hepatic news, bilateral renal veins, iliac veins, and portal vein, splenic vein, superior mesenteric vein (SMV). We perform sagittal, transverse and coronal scans of the great vessels in all patients. Gray-scale US, color Doppler, and spectral analysis are generally applied in all patients to evaluate the hemodynamics of the vessels. In this review, we briefly discuss variety of abnormalities of abdominal aorta and its branches, including atherosclerosis, aneurysm, stenosis, occlusion, arterio-venous shunt. We also introduce the abnormalities of IVC and its major tributaries, including retrocaval ureter, left side IVC, double IVCs, retroaortic left renal vein, interruption of suprarenal IVC, Budd-Chiari syndrome, and tumors of the great vessels or patudogies adjacent to the great vessels: pathologies of the mesentery are also reviewed. Challenges and Pitfalls in Abdominal US –Biliary System
Department of Radiology, Taichung Veterans General Hospital In the diagnosis of gallbladder and biliary diseases, ultrasound has become one of the most important screening and diagnostic tool, for being no need for pre-examination preparation and radiation exposure. The ultrasound images have a high contrast resolution, which is advantageous in differentiating the subtle changes in the gallbladder structures, biliary tract conditions, and pathologies. It is accurate in diagnosing and differentiating obstructive jaundice. Ultrasound has already replaced most of the traditional imaging methods as the first line diagnosis of biliary system. The indications for ultrasound examination of the gallbladder and biliary tract includes abdominal pain, palpable abnormalities, hepatomegaly, jaundice, abnormal laboratory data, follow-up for known or suspected abnormalities in the abdomen, abdominal trauma, and pre- and post-operative evaluation. There are no absolute contraindications for the ultrasound examination of the biliary system. The sonographic features and pitfalls of different biliary diseases were described. In the gallbladder pathologies, we included gallstones, tumors of gallbladder, acute cholecystitis, and its complications. In the bile duct, we included biliary obstruction, choledocholithiasis, and malignant tumor. Finally, the interventional procedures were introduced, in which we included: (1). real-time ultrasound guided aspiration cytology and biopsy; (2). percutaneous transhepatic cholangiography or drainage. In gallbladder diseases, ultrasound is advantageous for the presentation of bile as an echo-free fluid. Any subtle abnormalities can be easily detected better than any other modalities. Ultrasound is the best choice in screening and diagnosis of gallbladder diseases. This is why most of the hospitals already apply ultrasound as an important item in physical checkup. In the bile tract diseases, ultrasound is very good for differentiating obstructive jaundice, assessing the site, and the cause of obstruction. Therefore, we considered that ultrasound is a useful modality for diagnosis of biliary diseases. Ultrasound also plays an important role in guiding the interventional procedures and follow-up of biliary diseases. Proceeding of 2010 Annual Convention TSUM General Ultrasound
Challenges and Pitfalls in Abdominal US – Kidney
Department of Radiology Tri-Service General Hospital and National Defense Medial Center Ultrasonography of normal anatomy of the kidneys: The kidneys are surrounded by reflected echoes of perirenal fat. The renal parenchyma surrounds the fatty renal sinus. The renal sinus is imaged as an area of intense echoes. The renal cortex its echoes are less intense than those from normal liver, whereas the medullary pyramids are relative echo free. The renal variants include column of Bertin, dromedary hump, junctional parenchyma defect, lobar dysmorphism, duplex collecting system and extrarenal pelvis. Some Misconceptions and Pitfalls in Ultrasonography • Poor understanding of anatomy and/or embryological or developmental features of certain • Inadequate observation of ultrasonographic findings. • Misinterpretation The pitfalls in the ultrasonographic diagnosis of renal cystic lesions Renal cystic disease—simple cysts, parapelvic cysts(differentiate from hydronephrosis) , acquired cystic disease of dialysis, adult polycystic kidney disease, infantile polycystic kidney disease, von Hippel-Lindau cysts and mimicking cysts(calyceal diverticulum, focal dilated calyx and renal artery aneurysm) 1. calyceal diverticulum 2. focal dilated calyces 3. renal parenchyma AVM 4. renal artery aneurysm. The pitfalls in the ultrasonographic diagnosis of hydronephrosis 1. parapelvic cyst 2. renal hilar vessels prominence The pitfalls in the ultrasonographic diagnosis of renal masses Renal neoplasms—renal cell carcinoma (include von Hippel-Lindau disease), transitional cell carcinoma, squamous cell carcinoma, renal lymphoma(multiple masses, solitary mass, infiltrative disease, and perirenal disease), wilms’ tumor, metastases, angiomyolipoma, oncocytoma and renal pseudotumors(dromedary hump, column of Bertin hypertrophy and fetal lobation). Proceeding of 2010 Annual Convention TSUM General Ultrasound
1. dromedary hump 2. fetal lobation 3. column of Bertin hypertrophy 4. renal parenchyma scarring The pitfalls in the ultrasonographic diagnosis of renal stones Renal stones—calyceal stone, staghorn stone, radiolucent stones. 1. arcuate artery reflection 2. medullary nephrocalcinosis 3. focal medullary spongy kidney 4. renal artery calcification 5. renal artery aneurysm with calcification 6. TB kidney (autonephrectomy) 7. focal emphysematous pyelonephritis The pitfalls in the investigation of renal failure (Malfunctioning kidney—renal(medical renal disease) and postrenal(surgical renal disease) 1. acute pyelonephritis 2. acute renal cortical necrosis 3. renal hemosiderosis 4. kidney diffuse metastasis 5. kidney diffuse UCC 6. lymphoma diffuse infiltration 7. renal infarction Proceeding of 2010 Annual Convention TSUM General Ultrasound
Sonography of Adrenal Gland: Challenges and Pitfalls
Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou College of Medicine, Chang Gung University The normal adrenal glands are a pair of thin and flat organs located superior and medial to the kidneys deep in the retroperitoneum. Each gland consists of an anteromedial ridge and two wings (limbs) that open postero-laterally. The glands are confined by the ribs and transverse process of the spine on both sides, and by the stomach and bowel gas on the left. The organ measures 0.3 to 0.6 cm in thickness, 4 to 6 cm in length and 2 to 3 cm in width. Due to the deeper retroperitoneal location and small size, delineation of the normal adrenal glands and small adrenal lesions has been one of the challenges in ultrasonography (US). To resolve the scanning difficulty in US, the right adrenal gland is usually evaluated by transverse oblique scan and coronal scan through the anterior and middle axillary line, respectively. While the left one is investigated by an oblique coronal scan mainly through the posterior axillary line. The delineation of adrenal lesions depends on a number of factor, these include scanning technique and expertise of the operator, the body status of the patients, the size and functional status of the lesions, and the sonographic quality. A normal left adrenal gland may be located down to the level of renal hilum by a frequency of 10%. Due to the aforementioned reason, the diagnostic accuracy of US for adrenal lesions is variable, it has a sensitivity of 74-97%, a specificity of 61-96%, and an accuracyof 70-97%. Small size of adrenal nodules, ileus, obesity, fatty liver and large body feature account for majority of inaccuracy. Various structures or lesions in vicinity of adrenal glands may lead to pitfall and false positives in US. These include protruded masses from the viscera (e.g. liver, pancreas, or upper kidney), primary retroperitoneal tumors, accessory spleens, medial tubercle of spleen, gastric fundus, small bowels, enlarged nodes, pancreatic tails, engorged vessels and collaterals. Proceeding of 2010 Annual Convention TSUM General Ultrasound
First Report on Real-time Fusion of Adrenal Scinitigraphy with
Ultrasound in a Patient with Autonomous Adrenocortical Adenoma
Kuan-Yung Chen, Chien-Hua Chen, Yung-Hsiung Yeh, Minho Huang, Guang-Uei Hung Chang Bing Show Chwan Memorial Hospital Background Recently, we developed a method of fusing nuclear medicine images into the real-time virtual sonography, which can display the same cross-sectional multiplanar reconstruction images of CT or MRI to facilitate localizing the target lesions during performing sonography. Here we reported a case suspected of a hyperfunctioning adrenocortical adenoma referred for adrenal scintigraphy with dexamethasone-suppression 131I-6β-iodomethyl-19-norcholesterol (NP-59) and the adrenal scintigraphy was successfully fused in real-time with sonography. Materials and Methods 3 days before and 5 days after the NP-59 injection, the patient was given 8 mg of oral dexamethasone daily in divided doses to suppress normal adrenal uptake of NP-59. After intravenous injection of 37 MBq of NP-59, planar images were obtained 3, 4 and 5 days later. SPECT/CT (Hawkeye4, GE healthcare, Israel) also performed when positive uptake was shown. Then the data of SPECT/CT was imported into the ultrasound scanner equipped with virtual navigation system (MylabTM70 XVG, Esaote, Italy). Results A positive uptake of NP-59 was noted in posterior aspect of left upper abdomen on the 5-day image. The SPECT/CT localized this lesion in left adrenal gland, consistent with an autonomous adrenocortical adenoma. After processing the SPECT/CT data into a single DICOMM format, which recorded the positive NP-59 uptake on the co-registered CT volume images, the data were imported into the ultrasound scanning. With the guidance of SPECT/CT images, the target lesion in left adrenal gland was rapidly localized on the sonography, showing as a hypoechoic nodule. Conclusion To the best of our knowledge, this presented case should be the first one that fused adrenal scintigraphy in real-time with ultrasound. Further study will be warranted to approve the clinical utility of adrenal scintigraphy guided real-time virtual sonography in the diagnosis and management of adrenal disease. A Rare Case of Splenic Infarction in Post-traumatic Pancreatitis
Pei-Yu Lee1,2, Yeu-Sheng Tyan1,2, Teng-Fu Tsa1,2 1Department of Medical Imaging, Chung Shan Medical University Hospital 2School of Medical Imaging and Radiological Sciences, Chung Shan Medical University Splenic infarction usually occurs in patients with history of hematologic disease, sepsis or trauma. When patient presented with acute onset left upper abdominal pain, bedside abdominal ultrasound may be a useful tool for initial evaluation. Hypoechoic wedge-shaped or rounded parenchyma change is typical of splenic infarction on gray-scale ultrasound. Absence of flow in infarction area is also common under color or power Doppler flow examination. Herein, we report a case of incidentally finding of splenic infarction. The patient suffered from post-traumatic pancreatitis months ago. The ultrasound and CT images are reviewed. Proceeding of 2010 Annual Convention TSUM

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