Normal and Abnormal Spleen Lectures PDF

‫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:‬‬ ‫طلب...

‫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.