Ultrasound Imaging PDF - Al-Kitab University 2012

Ministry of Higher Education and Scientific Research Al-Kitab University College of Medical Techniques Radiology and Ultrasonic.Dept 4th Stage Ultrasound Imaging First Semester Theory L-6 Dr. Rezan H Muhammed Cystic lesions in normal or large liver Cystic lesions in normal or large liver Simple hepa...

Ministry of Higher Education and Scientific Research Al-Kitab University College of Medical Techniques Radiology and Ultrasonic.Dept 4th Stage Ultrasound Imaging First Semester Theory L-6 Dr. Rezan H Muhammed Cystic lesions in normal or large liver Cystic lesions in normal or large liver Simple hepatic cysts are common benign liver lesions and have no malignant potential. They can be diagnosed with ultrasound, CT, or MRI Simple hepatic cysts are one of the commonest liver lesions, occurring in ~5% (range 2-7%) of the population. Hepatic cysts are typically discovered incidentally and are almost always asymptomatic. Cystic lesions in normal or large liver 1. Well defined solitary cyst: A well rounded, echo-free mass with acoustic enhancement, usually less than 3 cm in diameter, and often a chance finding without symptoms, is likely to be a solitary simple congenital cyst. A small hydatid cyst must also be excluded and cannot always be differentiated sonographically It is usually an incidental finding during the ultrasound scan. Frequently , small cysts are peripheral and therefore more likely to be missed on ultrasound than CT. Transverse scan: a simple hepatic cyst with a sharp outline and acoustic enhancement. 2. Solitary cyst with a rough irregular outline. See liver abscess 3. Multiple cystic lesions. Multiple spherical cystic masses of varying sizes, completely echo-free with a sharp outline and posterior acoustic enhancement, may indicate congenital polycystic disease. Search for cysts in the kidney, pancreas and spleen; congenital cystic disease can be very difficult to differentiate from hydatid disease. Congenital poly cystic disease of the liver 4. Complex cyst. Haemorrhage or infection of any cyst may result in internal echoes and resemble an abscess or necrotic tumour. Some cysts may contain a thin septum, which is not a significant finding. However, cysts which contain solid nodules or thickened walls should be viewed with suspicion. Haemorrhage in to a cyst which on ultrasound resemble an abscess or necrotic tumour 5. Echinococcal cyst. Hydatid disease can present a broad spectrum of sonographic features. Ultrasound has a >90% sensitivity for the diagnosis of hydatid cyst. At ultrasound hydatid cysts may be single or multiple and have a number of described appearances, largely dependent upon the stage of the disease as follows: ✓ Initially they can appear as simple cysts. Distinguishing features include: a double linear echo to the cyst wall, fine echogenic debris (hydatid sand) within the cyst, which can be accentuated by moving the patient and there may be evidence of cyst wall calcification. Ultrasound is the most sensitive modality for the detection of membranes, septa and hydatid sand. ✓ Multivesicular cysts represent the presence of multiple daughter cysts , sometimes separated by echogenic matrix material. ✓ Calcification of the cyst wall can be partial or complete and dense, with the latter producing a strong acoustic shadow. Partial calcification does not always indicate death of the cyst The main complication of hepatic hydatid is cyst rupture (50– 90%). Before needle aspiration of an apparently solitary cyst , scan the whole abdomen and x-ray the chest. Hydatid cysts are usually multiple and may be dangerous to aspirate. A simple, centrally echo-free intrahepatic cyst with a sharp outline and distal acoustic enhancement. Because of the host reaction there is double wall around the Hydatid cyst An echo free mass containing a fine internal debris due to hydatid sand , this may float freely or be at the bottom of the cyst Well define cystic mass with internal debris and a membrane floating within the cyst. this is pathognomonic for hydatid cyst A complex mass containing multiple internal cyst and daughter vesicles , with echogenic material filling some of the cyst with intervening spaces.This usually indicate viable cyst Infected hydatid cysts are difficult to differenciated from abscesses or other masses. The hazy outline of this cyst indicate the posibility of infection An echogenic mass with a sharp outline and calcification in the wall. This may indicate a dead hydatid cyst. Hepatoma and liver abscesses seldom calcify. A hydatid cyst that has partially collapsed may resemble a scar A small collapsed hydatid cyst with calcification in the wall cystic focal liver lesions-differential diagnosis References: Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. Paul L. Allan, Grant M. Baxter, Michael J.Weston. Clinical Ultrasound. Volume one, 3rd Edition, 2011. Ministry of Higher Education and Scientific Research Al-Kitab University College of Medical Techniques Radiology and Ultrasonic.Dept 4th Stage Ultrasound Imaging First Semester Theory L-5 Dr. Rezan H Muhammed Abnormal live Reference: Palmer, Philip ES, ed. Manual of diagnostic ultrasound. World Health Organization, 2002. Enlarged liver/hepatomegaly: homogeneous pattern When the liver is enlarged but has a normal diffuse homogeneous echo pattern. consider the following: Congestive cardiac failure: The hepatic veins will be dilated. The inferior vena cava does not vary on respiration. Associated with pleural effusion above the diaphragm Hepatomegally ,dialated hepatic vein , pleural effusion, Acute hepatitis. There are no characteristic sonographic changes, but the liver may be enlarged and tender. Transverse scan: oedema of the wall of the gallbladder, but normal hepatic parenchyma Tropical hepatomegaly. The only significant finding is liver enlargement, usually associated with splenomegaly. Schistosomiasis. The liver can be either sonographically normal or enlarged, with thickening of the portal vein and the main branches, which become highly echogenic, especially around the porta hepatis. Transverse scan: showing fibrosis around the portal vein due to the Schistosomiasis Enlarged liver: non-homogeneous pattern 1- Without discrete masses. when there is increased echogenicity in the liver parenchyma, with loss of the highly reflective edges of the peripheral portal veins, cirrhosis, chronic hepatitis or a fatty liver should be suspected. Fatty liver 2- With multiple echogenic masses. Multiple masses of various Sizes, shapes and echo textures, producing a non-homogeneous echo pattern throughout the liver, are consistent with: Macronodular cirrhosis. The liver is enlarged with echogenic masses of various sizes but with normal intervening tissue. The normal vascular anatomy is distorted. Multiple abscesses. These are usually ill defined, with strong back wall echoes and internal echoes. Multiple metastases. These may be hyperechogenic or hypo echogenic and well circumscribed or ill defined, or both. Metastases are often more numerous and more variable in size than abscesses. multinodular hepatocarcinoma can resemble metastases. Lymphoma. This may be considered when there are multiple hypoechogenic masses in the liver, usually with irregular outlines and without associated acoustic enhancement. It is not possible to distinguish between lymphoma and metastases by ultrasound Haematomas. These are often irregular in outline, with acoustic enhancement. However, when blood has clotted, the haematomas may be hyperechogenic. It is important to obtain a clinical history of either trauma or anticoagulant medication. Macronodular cirrhosis Multiple hepatic abscesses Transverse scan: multiple well-defined metastases in the liver Lymphomatous masses in the liver Small liver/shrunken liver A diffusely increased echogenicity and distorted portal and hepatic veins in a shrunken liver are usually due to micronodular cirrhosis. This is often associated with portal hypertension, splenomegaly, ascites, dilated splenic veins and multiple varices. If the lumen of portal vein is filled with echoes, there may be thrombosis.which can extend into the splenic and mesenteric veins. Some patients with this type of cirrhosis may have a liver that appears normal in the early stages. Ascites with shrunken liver : the result cirrhosis Ministry of Higher Education and Scientific Research Al-Kitab University College of Medical Techniques Radiology and Ultrasonic.Dept 4th Stage Ultrasound Imaging First Semester Theory L-1 Dr. Rezan H. Muhammed Principles of Ultrasound Principles of Ultrasound Ultrasound is an imaging technique where highfrequency sound waves (2-15MHz) are used to generate an image. An ultrasound wave is produced by a probe using the piezoelectric effect: Certain crystalline structures will vibrate at a particular frequency when a certain voltage is applied across them. The conversion of electrical energy to kinetic energy is how the ultrasound probe creates an ultrasound wave. Similarly, they can generate a voltage when a vibration is induced in them This is how the probe interprets reflected waves. Ultrasound machine Ultrasound machine Ultrasound probes Basic Principles 1.Spatial resolution: How close two separate objects can be to each other and still be distinguishable. It is divided into:. Axial resolution: how far apart two objects can be when one is above the other (in the direction of the beam). Lateral resolution: how far apart two objects can be when side-by-side. 2.Contrast resolution: is how similar two objects can appear (in echogenic appearance) and still be distinguishable 3.Higher frequency: settings offer greater spatial resolution but decreased penetration 4.Lower frequency: settings offer reduced spatial resolution but increased penetration They are used for visualising deep structures. Affect of Tissues on Ultrasound At tissue interfaces, the wave may be: 1.Absorbed 2.Reflected 3.Transmitted 4.Scattered 5.Attenuated Modes Ultrasound modes include: 1.A- mode (amplitude mode): is the simplest type of ultrasound. 2.B-Mode or 2D mode(brightness mode). 3.M-Mode (movement mode). 4.Doppler mode :this mode makes use of the Doppler effect in measuring and visualizing blood flow. B-Mode