US Abdulsatar 35-66.pdf

‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬فحوصات الموجات فوق الصوتية‬ ‫العنوان‪:‬‬ ‫المرحلة‪ :‬الرابعة‬ ‫‪Title:‬‬ ‫‪Thick gallbladder walls, Small gallbladder, Gallbladder in jaundice‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدال...

‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬فحوصات الموجات فوق الصوتية‬ ‫العنوان‪:‬‬ ‫المرحلة‪ :‬الرابعة‬ ‫‪Title:‬‬ ‫‪Thick gallbladder walls, Small gallbladder, Gallbladder in jaundice‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ Introduction: :‫المقدمة‬ Thickening of the gallbladder wall is a relatively frequent finding on diagnostic imaging studies. Historically, a thick-walled gallbladder has been regarded as proof of primary gallbladder disease, and it is a well-known hallmark feature of acute cholecystitis. The finding itself, however, is nonspecific and can also be found in a variety of conditions unrelated to intrinsic gallbladder disease. Diffuse gallbladder wall thickening may produce a diagnostic problem because it occurs in symptomatic and asymptomatic patients and in patients with and those without an indication for cholecystectomy. Misinterpretation of the cause of this imaging finding can lead to an unnecessary cholecystectomy in patients without intrinsic gallbladder disease and, conversely, misdiagnosis in patients who do require a cholecystectomy may result in delayed treatment with increased morbidity. In this essay, we discuss and illustrate the various causes of a thickened gallbladder wall because knowledge of its differential diagnosis is essential for the correct interpretation of this finding. Pretest: :‫االختبار القبلي‬ What is the association between gallbladder wall and acute cholecystitis? Scientific Content: :‫المحتوى العلمي‬ Sonography, CT, and MRI all allow direct visualization of the normal and thickened gallbladder wall. Traditionally, sonography is used as the initial imaging technique for evaluating patients with suspected gallbladder disease because of its high sensitivity in the detection of gallbladder stones, its real-time character, and its speed and portability. However, CT has become popular for evaluating the acute abdomen and often is the first technique to show gallbladder wall thickening, or CT may be used as an adjunct to an inconclusive sonography examination or for staging of disease. The potential value of MRI in the evaluation of gallbladder disease , but it still plays little role. The normal gallbladder wall appears as a pencil-thin echogenic line on sonography and is usually visible on CT as a thin rim of soft-tissue density that enhances after contrast injection. The thickness of the gallbladder wall depends on the degree of gallbladder distention, and pseudothickening can occur in the postprandial state. A thickened gallbladder wall measures more than 3 mm, typically has a layered appearance at sonography, and frequently contains a hypodense layer of subserosal edema that mimics pericholecystic fluid at CT. Thick gallbladder walls Generalized thickening The thickness of the gallbladder wall is normally less than 3 mm and should not exceed 5 mm. When the thickness is between 3 m m and 5 mm, careful clinical correlation is needed. Generalized thickening of the gallbladder wall can occur in the following conditions: Acute cholecystitis. Chronic cholecystitis. Hypoalbuminaemia resulting from cirrhosis. Check for ascites, dilated portal veins and splenomegaly. Congestive cardiac failure. Check for ascites, pleural effusions, and dilated inferior vena cava and hepatic veins. Examine the patient. Chronic renal insufficiency. Examine the kidneys and the urine. Multiple myeloma. Hyperplasticcholecystosis. Localized thickening Local thickening of the gallbladder walls may be due to the following: Mucosal folds. Polyp. Primary or secondary carcinoma of the gallbladder. Small gallbladder The patient may recently have had a meal containing fat and the gallbladder has contracted. Chronic cholecystitis: check for thickened gallbladder walls and for gallstones within the gallbladder. Jaundice When the patient is jaundiced, ultrasound can usually differentiate between nonobstructive and obstructive jaundice, by showing the dilatation of the biliary system. Normal bile ducts - Extrahepatic ducts. It may be difficult to see the extrahepatic bile ducts. - Intrahepatic ducts. The intrahepatic ducts are best seen on the left side of the liver in deep inspiration. It is not easy to see the normal intrahepatic ducts on ultrasound because they are often too small and thin-walled. Maximum diameter of normal common hepaticduct: less than5 mm Maximum diameter of normal common bileduct: less than 9mm Maximum diameter of common bile duct post-cholecystectomy:10-12mm Sometimes following surgery, and in patients over 70 years of age, the common bile duct may be a few millimetres wider (i.e. 12-14 mm). Add 1 mm to all of the measurements above for each decade over 70 years of age. Gallbladder in jaundice 1. If the gallbladder is distended, the obstruction usually affects the common bile duct (e.g. calculus, Ascaris,pancreatitis or carcinoma). The hepatic ducts will also be distended. 2. If the gallbladder is not distended or is very small, obstruction is unlikely or the obstruction is above the level of the cystic duct (e.g. enlarged lymph nodes or tumour near the porta hepatis). Posttest: :‫االختبار البعدي‬ What are the possible causes of generalized thickened of gall bladder wall? References: :‫المصادر‬ Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. Van Breda Vriesman, A. C., Engelbrecht, M. R., Smithuis, R. H., & Puylaert, J. B. (2007). Diffuse gallbladder wall thickening: differential diagnosis. American Journal of Roentgenology, 188(2), 495-501. ‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬فحوصات الموجات فوق الصوتية‬ ‫المرحلة‪ :‬الرابعة‬ ‫العنوان‪:‬‬ ‫‪Title:‬‬ ‫‪Normal and abnormal pancreas‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ :‫المقدمة‬ Introduction: Pancreatic ultrasound can be used to assess for pancreatic malignancy, pancreatitis and its complications, as well as for other pancreatic pathology. As ultrasound (US) is simple and less invasive than other imaging modalities, this technique is widely used for mass screening. However, visualizing the entire pancreas due to complicated anatomy, obesity and overlying gas can be difficult. US plays a key role in the diagnosis of pancreatic carcinoma (PC). To detect these forms of PC, main pancreatic duct (MPD) dilatation (3 mm or more) and pancreatic cysts (5 mm or larger) are US findings of high-risk individuals (HRIs), and these subjects should be observed periodically. Scanning maneuvers are also important for both screening for PC and follow-up of HRIs. As lesions in the groove area and ventral pancreas do not affect the MPD or extrahepatic bile duct, we should pay attention to these areas. Visualization of the tail is also challenging due to gas and stool in the alimentary tract. As the position of the pancreas changes depending on the body posture, and several different body positions should be employed, such as the right lateral decubitus, sitting, and upright positions, rather than only applying strong compression with the transducer. In cases with poor visualization, the liquid-filled stomach method is highly recommended. Pretest: What is the echo pattern and size of normal pancreas? :‫االختبار القبلي‬ Scientific Content: :‫المحتوى العلمي‬ Indications Midline upper abdominal pain, acute or chronic. Jaundice. Upper abdominal mass. Persistent fever, especially with upper abdominal tenderness. Suspected malignant disease. Recurrent chronic pancreatitis. Suspected complications of acute pancreatitis, especially pseudocyst or abscess. Polycystic kidneys: cysts in the liver or spleen. Direct abdominal trauma, particularly in children. The pancreas can be very difficult to identify, especially the tail. Gas If bowel gas obscures the image: - Try gentle compression with the transducer or use decubitus views, both right and left. - If necessary, give the patient 3 or 4 glasses - of water, wait a few minutes to allow the bubbles to disperse and then repeat the - examination with the patient sitting or standing, viewing the pancreas through the water-filled stomach. Transverse scanning Start with transverse scans across the abdomen moving downwards towards the feet until the splenic vein is seen as a linear, tubular structure with the medial end broadened. This is where it is joined by the superior mesenteric vein , at the level of the body of the pancreas. The superior mesenteric artery will be seen in cross-section just below the vein. By angling and rocking the transducer, the head and the tail of the pancreas may be seen. Continue transverse scans downwards to visualize the head of the pancreas and the uncinate process (if present) between the inferior vena cava and the portal vein. Normal pancreas The pancreas has about the same echogenicity as the adjacent liver and should appear homogeneous. However, the pancreatic echogenicity increases with age. The outline of the normal pancreas is smooth. When scanning the pancreas, certain anatomical landmarks should be identified, in the following order: Aorta Inferior vena cava Superior mesenteric artery Splenic vein Superior mesenteric vein Wall of the stomach Common bile duct The essential landmarks are the superior mesenteric artery and the splenic vein. Normal pancreatic size There is great variability in the size and shape of the pancreas. The following guidelines may be helpful. The average diameter of the head of the pancreas: 2.8 cm. The average diameter of the medial part of the body of the pancreas: less than 2 cm. The average diameter of the tail of the pancreas: 2.5 cm. The diameter of the pancreatic duct should not exceed 2 mm. Small pancreas The pancreas is usually smaller in elderly people, but this is not of clinical significance. When there is overall atrophy of the pancreas, the decrease in size is usually uniform throughout the pancreas. If there appears to be atrophy of the tail of the pancreas alone (the head appearing-normal), then a tumour in the head oft h e pancreas must be suspected. The head must be scanned carefully because chronic pancreatitis in the body and tail may be associated with a slow- growing tumour in the head of the pancreas (Fig-7). If the pancreas is small and irregularly hyperechogenic and non- homogeneous compared with the liver, the cause is usually chronic pancreatitis. Fig-7: A small. nonhomogeneous pancreas with calcifications due to chronic pancreatitis Diffuse enlargement of the pancreas In acute pancreatitis, the pancreas may be diffusely enlarged and either normal or hypochogenic compared with the adjacent liver. The serum amylase is usually elevated, and there may be local ileus due to bowel irritation. When the pancreas is irregularlyhyperechogenic and diffusely enlarged, there is usually acute pancreatitis superimposed on chronic pancreatitis. Focal enlargement (noncystic) Almost all pancreatic tumours are hypochogenic compared with the normal pancreas. It is not possible to distinguish between focal pancreatitis or pancreatic tumour by ultrasound alone. Even if the serum amylase is elevated, repeat the ultrasound examination in 2 weeks to assess the change. Tumour and pancreatitis can co-exist.When the pattern is mixed, biopsy is needed. Pancreatic cysts True pancreatic cysts are rare. They are usually single, echo-free, smooth cavities filled with fluid. Small multiple cysts may be con- genital. An abscess or haematoma in the pancreas will appear as a complex mass, often associated with severe pancreatitis. Pseudocysts following trauma or acute pancreatitis are not uncommon; they may increase in size and rupture. Such cysts can be single or multiple. In the early stages they are complex, with internal echoes and ill-defined walls, but eventually these cysts become smooth-walled and echo-free. Pancreatic cystadenoma or other cystic tumours usually appear on ultrasound as multiseptate cystic masses with associated solid components. Hydatid cysts are unusual in the pancreas. Calcification in the pancreas Ultrasound is not the best way to assess pancreatic calcification. A supine anteroposterior radiograph of the upper abdomen is preferable. Calcification within the pancreas can produce acoustic shadowing. However, fi the calcification is very small, there may only be bright discrete echoes without shadowing. Calcification is usually due to: Chronic pancreatitis. Calculi in the pancreatic duct. Biliary calculi in the distal common bile duct can be mistaken for pancreatic calcification. There is usually dilatation of the proximal bile duct. Dilatation of the pancreatic duct The normal maximum internal diameter of the pancreatic duct is 2 mm. The causes of dilatation of the pancreatic duct are: Tumour of the head of the pancreas or of the ampulla of Vater. Both are usually associated with jaundice and dilatation of the biliary tract. Calculus in the common pancreatic duct. Calculus in the intrapancreatic duct. Chronic pancreatitis Postoperative strictures following Whipple's operation or partial pancreatectomy. The clinical history should be verified with the patient or relatives if necessary. Posttest: :‫االختبار البعدي‬ How does the pancreas appear in elderly people? References: :‫المصادر‬ Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. ‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬فحوصات الموجات فوق الصوتية‬ ‫المرحلة‪ :‬الرابعة‬ ‫العنوان‪:‬‬ ‫‪Title:‬‬ ‫‪Normal and abnormal spleen‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ Introduction: :‫المقدمة‬ The spleen is an organ of the hematological system and has a role in immune response, storage of red blood cells and hematopoiesis. The spleen is a wedgeshaped organ lying mainly in the left upper quadrant (left hypochondrium and partly in the epigastrium) and is protected by the left 9th to 11th ribs. It is soft, highly vascular and dark purple in color. Size and weight vary from person-to-person but on average is around 2.5 cm thick, 7.5 cm broad and 12.5 cm in length. For pediatric measurements, see the article spleen size (pediatric). The spleen has two poles (superior and inferior), three borders (superior, inferior and intermediate) and two surfaces (diaphragmatic and visceral). It is enclosed by a thin capsule, which is easily ruptured. The spleen is completely covered by peritoneum, except at the hilum, which forms a number of ligaments. Pretest: What are the causes of splenomegaly? :‫االختبار القبلي‬ Scientific Content: :‫المحتوى العلمي‬ Indications Splenomegaly (enlarged spleen) Left abdominal mass Blunt abdominal trauma Left upper abdominal pain (an erect abdominal X-ray, including both sides of the diaphragm, is also needed fi perforation of the bowel is suspected) Suspected subphrenic abscess (pyrexia of unknown origin) Jaundice combined with anaemia Echinococcosis (hydatid disease) Ascites or localized intra-abdominal fluid Suspected malignancy, especially lymphoma or leukaemia. Normal spleen It is important to identify the: Left hemi-diaphragm. Splenic hilus. Splenic veins and relationship to pancreas. Left kidney (and renal/splenic relationship). Left edge of liver. Pancreas. When the spleen is normal in size, it can be difficult to image completely (Fig-8). Fig-8: Oblique scan: normal spleen and left kidney Echo pattern The spleen should show a uniform homogeneous echo pattern. It is slightly less echogenic than the liver. Abnormal spleen Enlarged spleen/splenomegaly There are no absolute criteria for the size of the spleen on ultrasound. When normal, it is a little larger than or about the same size as the left kidney. The length should not exceed 15 cm in the major axis. A chronically enlarged spleen may often distort and displace the left kidney. Homogeneous splenomegaly This may be due to: Tropical splenomegaly, which includes idiopathic splenomegaly, malaria, trypanosomiasis, leishmaniasis and schistosomiasis (Fig-9). Sickle cell disease (unless infarcted). Portal hypertension. Leukaemia. Metabolic disease. Lymphoma (may contain hyperechogenic masses). Infections such as rubella and mononucleosis. Whenever there is splenomegaly, examine the liver for size and echogenicity. Also examine the splenic and portal veins, the inferior vena cava, hepatic veins and mesentery for thickening. Fig-9: Longitudinal scan: gross splenomegaly (due to leishmaniasis) compressing the left kidney. Non-homogeneous spleen, with or without splenomegaly Well defined cystic lesion If there is a clearly demarcated, echo-free mass with posterior acoustic enhancement, differentiate: Cystic disease (may be multiple). Examine liver and pancreas for cysts. Congenital cysts. These are usually solitary and may contain echoes as a result of haemorrhage Echinococcal (hydatid) cysts. These are usually clearly defined with a double wall (the pericyst and the cyst wall) and often septate. There will be markedly enhanced back wall echoes and often marked variation in the thickness of the wall of the cyst. However, hydatid cysts may appear as roughly rounded masses with an irregular contour and a mixed echo pattern resembling an abscess. The cyst can be hypochogenic with few irregular echoes or hyperechogenic and solid without any back wall shadow: combinations of these findings may occur. The walls of the-cyst may be collapsed or sagginga n d there may be a floating density within the cyst, or even a cyst within a cyst (which is pathognomonic for hydatid disease). There may be calcification within the wall of the cyst and there may be "sand" in the most dependent portion. Hematoma A regular but ill-defined cystic lesion in the spleen Scan in different projections. A hypoechogenic cystic area with an irregular outline, usually containing debris and associated with splenomegaly and local tenderness, suggests a splenic abscess. Examine the liver for other abscesses.After successful treatment, the abscess may resolve or become larger and almost echo-free, but is no longer tender. A similar cystic lesion which is larger and contains fluid may be a splenic abscess following-infarction resulting from sickle cell disease. Amoebic abscesses are very rare in the spleen: bacterial abscesses are more common. Splenic vein A normal splenic vein does not exclude portal hypertension. Enlarged splenic vein If the splenic vein appears large and remains more than 10 m m in diameter on normal respiration,portal hypertension should be suspected. When the portal vein is more than 13 mm in diameter and does not vary with respiration, there is a strong correlation with portal hypertension. Intrasplenic mass, with or without splenomegaly Splenic masses may be single or multiple and well defined or irregular in outline. Lymphoma is the commonest cause of an intrasplenic mass, and such masses are usually hypochogenic. Malignant tumours, either primary or metastatic, are rare and may be either hypo- or hyperechogenic. Splenic abscess: an irregular, hypoechogenic or complex cystic intrasplenic mass. Pyrexia (usually of unknown origin) If possible, check the total and the differential white cell count. Start with longitudinal scans. A perisplenic, subdiaphragmatic, echo-free or complex mass, superior to the spleen but limited by the left diaphragm, isprobably asubphrenic abscess. Trauma If there is free intraperitoneal or subphrenic fluid and an irregular splenic outline, a splenic tear or injury is likely. An echo-free or complex echo area at the periphery of the spleen, associated with general or localized splenomegaly suggests a subcapsular haematoma. Search carefully for free intra- abdominal fluid. An intrasplenic echo-free or complex, irregular mass suggests an acute haematoma. An accessory spleen may have the same appearance. An echogenic intrasplenic mass is probably an old haematoma. which has calcified, giving bright echoes with acoustic shadowing. A haemangioma may have the same appearance. An irregular, echo-free or complex mass may be a traumatic cyst or a damaged hydatid cyst. Posttest: :‫االختبار البعدي‬ What are the sonographic features of splenic abscess? References: :‫المصادر‬ Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. Surgical anatomy and technique. Springer. ISBN:0387095152. Drake. Gray's basic anatomy. Churchill Livingstone. ‫الجامعة التقنية الوسطى‬ ‫كلية التقنيات الصحية والطبية‪ /‬بغداد‬ ‫قسم ‪ :‬تقنيات االشعة‬ ‫المادة‪ :‬فحوصات الموجات فوق الصوتية‬ ‫العنوان‪:‬‬ ‫المرحلة‪ :‬الرابعة‬ ‫‪Title:‬‬ ‫‪Normal kidney and ureters, absent kidney, abnormal kidney: large kidney‬‬ ‫اسم المحاضر‪:‬‬ ‫‪Name of the instructor:‬‬ ‫م‪.‬عبدالستار عارف خماس‬ ‫الفئة المستهدفة‪:‬‬ ‫طلبة المرحلة الرابعة‬ ‫قسم تقنيات االشعة‬ ‫‪Target population:‬‬ :‫المقدمة‬ Introduction: A kidney ultrasound (renal ultrasound) is an imaging test that allows your healthcare provider to look at your right and left kidney, as well as your bladder. The kidneys are the filtration system of your body. They filter the waste products out of your blood. The waste products then leave your body as urine. Your healthcare provider may also need a “post void” done with this exam. This requires you to come to the test with a full bladder so that the provider can get a volume of your bladder before and after you empty it. Pretest: :‫االختبار القبلي‬ How to appear echogenicity of internal structures of kidneys? Scientific Content: Indications Renal or ureteric pain. Suspected renal mass (large kidney). Non-functioning kidney on urography. Haematuria. Recurrent urinary infection. Trauma. :‫المحتوى العلمي‬ Suspected polycystic disease. Pyrexia of unknown origin or postoperative complication. Renal failure of unknown origin. Schistosomiasis. Normal kidney Both kidneys should be about the same size. In adults, a difference of more than 2 cm in length is abnormal. Length: up to 12 cm and not less than 9 cm Width: normally 4-6 cm but may vary alittle with the angle of the scan Thickness: up to 3.5 cm but may vary a little with the angle of the scan The central echo complex (the renal sinus) is very echogenic and normally occupies about one-third of the kidney. (The renal sinus includes the pelvis, calyces, vessels and fat.) In the newborn, the kidneys are about 4 cm long and 2 cm wide. The renal pyramids are poorly defined hypochogenic areas in the medulla of the kidney, surrounded by the more echogenic renal cortex. It is easier to see the pyramids in children and young adults. When scanning it is important to identify the following: The renal capsule. This appears as a bright, smooth, echogenic line around the kidney (Fig-10). The cortex. This is less echogenic than the liver but more echogenic than the adjacent renal pyramids. The renal medulla. This contains the hypochogenic, renal pyramids which should not be mistaken for renal cysts. The renal sinus (the fat, the collecting system and the vessels at the hilus). This is the innermost part of the kidney and has the greatest echogenicity. The ureters. Normal ureters are not always seen: they should be sought where they leave the kidney at the hilus. They may be single or multiple and are often seen in the coronal projection. The renal arteries and veins. These are best seen at the hilus. They may be multiple and may enter the kidney at different levels. Fig-10: Longitudinal scan of a normal right kidney. Renal parenchymal thickness is measured between the cortex perirenal fat interface (capsule) and the sinus pyramid apex interface at the mid portion on long section of the kidney. Renal medullary pyramid thickness was measured as the distance between the apex and the base of pyramid at the mid portion of the kidney. Renal length is measured as the maximum bipolar dimension in longitudinal plane which showed central sinus echoes the best with the renal parenchyma evenly distributed all around the central sinus. Renal width is measured as the maximum distance between medial and lateral borders of kidney. Renal thickness or depth is measured as the distance between ventral and dorsal surfaces of the kidney. Renal cortical thickness is measured as the distance between the renal capsule and the external margin of the hypoechoic medulla (base of the renal pyramid) The volume of the entire kidney was calculated using the mathematical formula: Length (Cm) × width (Cm) × depth (Cm)/2 Adrenal (suprarenal) glands The adrenal glands are not easily seen with ultrasound. Absent kidney If either kidney cannot be seen, search again. Adjust the gain to show the liver parenchyma and spleen, and scan in different projections. Assess the size of the visible kidney. Hypertrophy of a kidney occurs (at any age) in a few months when the other kidney has been removed or is not functioning. If there is one large kidney and the other cannot be visualized after a careful search, it is probable that the patient has only one kidney. If one kidney cannot be demonstrated,consider the following possibilities: The kidney may have been removed. Check the clinical history and examine the patient for scars. The kidney may be ectopic. Search the kidney area and the whole abdomen, including the pelvis. If no kidney is found, X-ray the chest. Acontrast urogram may be necessary. If only one large but normal kidney is demonstrated, and there has not been any surgery, it is likely that there is congenital absence of the other kidney. If the only kidney visualized is not enlarged, a failure to demonstrate the other kidney suggests chronic disease. If there is one large but distorted kidney, there may be a developmental abnormality. Apparent absence of both kidneys may be a failure to demonstrate them with ultrasound because of changed echogenicity resulting from chronic disease of the renal parenchyma. Any kidney less than 2 cm thick and 4 cm long can be very difficult to visualize. Locate a renal vessel or ureter; thism a y help to localize the kidney, especially fi the ureter is dilated. Large kidney Bilateral enlargement - When the kidneys are enlarged but normal in shape, with normal, decreased or increased homogeneous echogenicity, the possible causes are: Acute or subacute glomerulonephritis or severe pyelonephritis. Amyloidosis. The nephrotic syndrome. - When the kidneys have a smooth outline and are uniformly enlarged, with non- homogeneous hyperechogenicity, the possible causes are: Lymphoma. Metastases. Polycystic kidneys. Unilateral enlargement If one kidney appears to be enlarged but has normal echogenicity, and the other kidney is small or absent, the enlargement may be due to compensatory hypertrophy. When no other kidney is seen, exclude crossed ectopia and other developmental abnormality. The kidney may be slightly enlarged because of persistent segmentation (duplication) with two or even three ureters. Search for the renal hilus: there are likely to be two or more vessels and ureters. One kidney is enlarged or more lobulated than normal The commonest cause of an enlarged kidney is hydronephrosis, which will appear on ultrasound images as multiple, well circumscribed cystic areas (the calyces) with a dilated central cystic area (the renal pelvis, normally less than 1 c m in width). Always compare the two kidneys when assessing the size of the renal pelvis. When much of the pelvis is outside the renal parenchyma, it may be a normal variant. When the renal pelvis is enlarged, normal echoes can be lost because of the fluid content A large renal pelvis may be due either to overhydration with increased urinary output or toa n overfilled urinary bladder. The renal calyces will be normal. Ask the patient to empty the bladder and rescan. Pelvic dilatation can occur normally in pregnancy and does not necessarily indicate infection. Check the urine for infection, and check the uterus for pregnancy. A large renal pelvis is an indication to scan the ureters and the bladder and particularly the other kidney to locate the obstruction. If no cause is identified, a contrast urogram will be necessary. The normal con- cave calyces may become inverted and rounded as the degree of ob- struction increases. Eventually the renal cortex becomes thinned. To assess the degree of hydronephrosis, measure the size of the renal pelvis when the bladder is empty. If the pelvis is wider than 1 cm, but there is no calyceal dilatation, the hydronephrosis is mild. When there is calyceal dilatation, the hydronephrosis is moderate. If there is loss of the renal cortex. it is advanced. Hydronephrosis can be caused by congenital obstruction of the uretero- pelvic junction, by ureteric stenosis (e.g. as in schistosomiasis) or a calculus, or from external pressure on the ureters by a retroperitoneal or abdominal mass. Posttest: :‫االختبار البعدي‬ What are the causes of bilateral enlargement of the kidneys? References: :‫المصادر‬ Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002.