Methods of Imaging the Hepatobiliary System PDF

 [Lecture 1 وزاري مادة الكورس الثاني ))] =================================================== **METHODS OF IMAGING THE HEPATOBILIARY SYSTEM** 1\. Plain film 2\. Ultrasound (US): \(a) Transabdominal \(b) Endoscopic \(c) Intraoperative 3\. Computed tomography (CT), includin...

 [Lecture 1 وزاري مادة الكورس الثاني ))] =================================================== **METHODS OF IMAGING THE HEPATOBILIARY SYSTEM** 1\. Plain film 2\. Ultrasound (US): \(a) Transabdominal \(b) Endoscopic \(c) Intraoperative 3\. Computed tomography (CT), including: \(a) Routine 'staging' (portal venous phase) CT \(b) Triple phase 'characterization' CT \(c) CT cholangiography 4\. Magnetic resonance imaging (MRI) 5\. Endoscopic retrograde cholangiopancreatography (ERCP) 6\. Percutaneous transhepatic cholangiography (PTC) 7\. Operative cholangiography 8\. Postoperative (T-tube) cholangiography 9\. Angiography---diagnostic and interventional 10\. Radionuclide imaging: \(a) Static, with colloid \(b) Dynamic , with iminodiacetic acid derivatives. **METHODS OF IMAGING THE PANCREAS** 1\. Plain abdominal films 2\. US: \(a) Transabdominal \(b) Intraoperative \(c) Endoscopic 3\. CT 4\. MRI 5\. ERCP 6\. Arteriography: \(a) Coeliac axis \(b) Superior mesenteric artery **PLAIN FILMS:** May incidentally demonstrate air within the biliary tree or portal venous system, opaque calculi or pancreatic calcification. Lecture 2 : (ULTRASOUND OF THE LIVER) ------------------------------------- [Indications of ultrasound of the liver] ---------------------------------------------------- 1. Suspected focal or diffuse liver lesion ------------------------------------------ 2. Jaundice ----------- 3. Abnormal liver function tests -------------------------------- 4. Right upper-quadrant pain or mass ------------------------------------ 5. Hepatomegaly --------------- 6. Suspected portal hypertension -------------------------------- 7. Staging known extrahepatic malignancy, superseded by CT ---------------------------------------------------------- 8. Pyrexia of unknown origin, now superseded by CT for patients over 30 years old --------------------------------------------------------------------------------- 9. To provide real-time image guidance for the safe placement of needles for biopsy ----------------------------------------------------------------------------------- 10. Assessment of portal vein, hepatic artery or hepatic veins -------------------------------------------------------------- 11. Assessment of patients with surgical shunts or transjugular intrahepatic portosystemic shunt (TIPS) procedures ------------------------------------------------------------------------------------------------------------------ 12. Follow-up after surgical resection or liver transplant ---------------------------------------------------------- [Contraindications of ultrasound of the liver] ---------------------------------------------------------- None. ----- [Patient Preparation of ultrasound of the liver] ------------------------------------------------------------ Fasting or restriction to clear fluids only required if the gallbladder is also to be studied. ---------------------------------------------------------------------------------------------- [Equipment of ultrasound of the liver] -------------------------------------------------- 3--5-MHz transducer and contact gel. Selection of protocol and positioning of focal zone depend on the type of machine, manufacturer and patient habitus. --------------------------------------------------------------------------------------------------------------------------------------------------------- [Technique of ultrasound of the liver] -------------------------------------------------- 1. Patient supine ----------------- 2. Time-gain compensation set to give uniform reflectivity throughout the right lobe of the liver ------------------------------------------------------------------------------------------------- 3. Suspended inspiration ------------------------ 4. Longitudinal scans from epigastrium.The transducer should be angled cephalad to include the whole of the left and right lobes. ---------------------------------------------------------------------------------------------------------------------------------- 5. Transverse scans, subcostally, to visualize the whole liver -------------------------------------------------------------- 6. If visualization is incomplete, due to a small or high-positioned liver, then additional right intercostal, longitudinal, transverse and oblique scans may be useful in respiration. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- \-\-\--In patients who are unable to hold their breath,Upright or left lateral decubitus positions. ---------------------------------------------------------------------------------------------------- 7\. Contrast-enhanced ultrasound of the liver uses microbubble agents to enable the contrast enhancement pattern of focal liver lesions. \-\-\--The lesion is identified on B mode scanning. The images are recorded after bolus injection of the contrast agent flushed with saline. Advantages: Feasible even in the presence of impaired renal function Disadvantages: Limited to single lesion visualization per pass [**Additional Views** ] **Hepatic veins** These are best seen using a transverse intercostal or epigastric approach.Hepatic vein walls do not have increased reflectivity in comparison to normal liver parenchyma. Doppler may be useful to examine flow within the hepatic segment. **Portal vein** The longitudinal view of the portal vein is shown by an oblique subcostal or intercostal approach. Portal vein walls are of increased reflectivity in comparison to parenchyma. **Hepatic artery** This may be traced from the coeliac axis, which is recognized by the 'seagull' appearance of the origins of the common hepatic artery and splenic artery. **Common bile duct** **Spleen** The spleen size should be measured in all cases of suspected liver disease or portal hypertension. Ninety-five percent of normal adult spleens measure 12 cm or less in length, and less than 7 × 5 cm in thickness. In children, splenomegaly should be suspected if the spleen is more than 1.25 times the length of the adjacent kidney. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- **ULTRASOUND OF THE GALLBLADDER AND BILIARY SYSTEM** **Indications** 1\. Suspected gallstones 2\. Right upper quadrant pain 3\. Jaundice 4\. Fever of unknown origin 5\. Acute pancreatitis 6\. To assess gallbladder function 7\. Guided percutaneous procedures **Contraindications** None. **Patient Preparation** Fasting for at least 6 h, preferably overnight. Water is permitted. **Equipment** 3--5-MHz transducer and contact gel. Selection of protocol and positioning will depend upon the **type of machine**, **manufacturer** and **patient habitus**. **Technique** 1\. The patient is supine. 2\. The gallbladder can be located by from the right portal vein to the gallbladder fossa. 3\. Developmental anomalies are rare. 4\. The gallbladder is scanned from the fundus to the neck, leading to the cystic duct. 5\. The gallbladder should then be rescanned in **the left lateral decubitus** or **erect positions**, because stones may be missed if only supine scanning is performed. 6\. Visualization of the neck and cystic ducts may be improved by head-down tilt. **Note: The normal gallbladder wall is never more than 3-mm thick**. **Additional Views** **Assessment of gallbladder function** 1\. Fasting gallbladder volume may be assessed by measuring **longitudinal, transverse and antero-posterior (AP) diameters.** 2\. Normal gallbladder contraction reduces the volume by **more than 25%,** 30 min after a standard fatty meal. **Intrahepatic bile ducts** 1\. Left lobe---Transverse epigastric scan 2\. Right lobe---Subcostal or intercostal longitudinal oblique normal intrahepatic ducts are visualized with modern scanners. Intrahepatic ducts are dilated if their diameter is more than 40% of the accompanying portal vein branch. **Extrahepatic bile ducts** 1\. The patient is supine or in a lateral position. 2\. The upper common duct is demonstrated on a **longitudinal oblique, subcostal or intercostal scan running anterior to the portal vein.** 3\. The common duct may be downward along its length through the head of the pancreas to the ampulla, and transverse scans should also be performed to improve detection of intraduct stones. Gas in the duodenum often impedes the view of the lower duct. **(the common hepatic duct) is 4 mm or less in a normal adult; 5 mm is borderline and 6 mm is considered dilated. The lower bile duct (common bile duct) is normally 6 mm or less**. **Colour-flow Doppler enables quick distinction of bile duct from hepatic artery.** **Postcholecystectomy** The normal common duct dilates after cholecystectomy. The common duct measures more than 4 mm age 40,plus 1mm for each decade over 40 and 1mm for Postcholecystectomy. ULTRASOUND OF THE PANCREAS **Indications** 1\. Suspected pancreatic tumour 2\. Pancreatitis or its complications 3\. Epigastric mass 4\. Epigastric pain 5\. Jaundice 6\. To facilitate guided biopsy and/or drainage **Contraindications** None. **Patient Preparation** Nil by mouth, preferably overnight. **Equipment** 3--5-MHz transducer and contact gel. Selection of protocol and positioning of focal zone will depend upon the type of machine, manufacturer and patient habitus. **Technique** 1\. The patient is supine. 2\. The body of the pancreas is located anterior to the splenic vein in a transverse epigastric scan. 3\. The transducer is angled transversely and obliquely to visualize the head and tail. 4\. The tail may be demonstrated from a left intercostal view using the spleen as an acoustic window. 5\. Longitudinal epigastric scans may be useful. 6\. The pancreatic parenchyma increases in reflectivity with age, being equal to liver reflectivity in young adults. 7\. Gastric or colonic gas may prevent complete visualization. This may be demonstrated by left and right oblique decubitus scans or by scanning with the patient erect. Water may be drunk to improve the window through the stomach. **The pancreatic duct should not measure more than 3 mm in the head or 2 mm in the body**. Endoscopic US and intraoperative US are useful adjuncts to transabdominal US. EUS may be used to further characterize and biopsy pancreatic solid and cystic lesions. Intraoperative US is used to localize small lesions (e.g. islet cell tumours prior to resection). Anatomy of biliary system  Ultrasound of biliary system **Ultrasound of pancreas**  **Ultrasound of liver**