1. Abdominal Imaging of Liver
Dr Mohamed El Safwany , MD.

2. Intended Learning Outcomes
The student should be able at the end of the lecture to recognize ultrasound principles of the liver

3. Anatomy
Protocols
Normal Ultrasound Findings

4. Anatomy of the Liver
The Liver occupies all of the right hypochondrium, the greater part of the epigastrium, and left hypochondrium. The ribs cover the greater part of the right lobe .In the epigastric region, the liver extends several centimeters below the xiphoid process. Most of the left lobe of the liver is covered by the rib cage.

5. Lobes of the Liver
Right lobe: The right lobe of the liver is the largest of the liver’s lobes. It occupies the right hypochodrium.
Left lobe: The left lobe of the liver lies in the epigastric and left hypochondriac region.
Caudate lobe: The caudate lobe is a small lobe situated on the posterosuperior surface of the left lobe opposite the tenth and eleventh thoracic vertebrae .

6. Hepatic Nomenclature
Couinaud’s system of hepatic nomenclature provides the anatomic basis for hepatic surgical resection. By using this system , the radiologist may be able to precisely isolate the location of a lesion for the surgical team

7. Couinaud’s hepatic segments divide the liver into eight segments
Couinaud’s hepatic segments divide the liver into eight segments . The hepatic veins are the longitudinal boundaries . The transverse plane is defined by the right and left portal pedicles .

8. Hepatic Segmental Anatomy
The caudate lobe (segmentⅠ) is situated posteriorly.
Segment Ⅰincludes the caudate lobe.
Segment Ⅱand Ⅲ includes the left superior and inferior lateral segment.
Segment Ⅳa and Ⅳb includes the medial segment of the left lobe.
SegmentⅤ and Ⅵ are caudal to the transverse plane .
Segments Ⅶ and Ⅷ are cephalad to the transverse plane.

9. Vascular Supply: Portal vein
The portal venous system is a reliable indicator of various ultrasonic tomographic planes throughout the liver. 80% of vascular supply Main portal vein Right main portal vein Left main portal vein

10. Hepatic artery : branch of abdominal aorta
Enters liver through porta hepatis
20%of arterial supply to liver
Divides in the liver into right and left branches

11. Hepatic veins The hepatic veins are divided into three
components: right,middle,and left.

12. Distinguishing Characteristics of Hepatic and Portal Veins
The best way to distinguish the hepatic from the portal vessels is to trace their points of entry to the liver. The hepatic vessels flow into the inferior vena cava, whereas the splenic veins and superior mesenteric vein join together to form the portal venous system.

13. Distinguishing Characteristics of Hepatic and Portal Veins
The walls of hepatic veins are thin-walled ,and the walls of portal veins are brightly reflective veins

14. The hepatic veins are easily differentiated from bile ducts and portal veins .
They are not surrounded by an echogenic wall
They originate close to the diaphragm , and can be traced into the inferior vena cava

15. Sonographic Evaluation of the Liver
Evaluation of the hepatic structure is one of the most important procedures in sonography for many reasons. The normal , basiclly homogenerous parenchyma of the liver allows imaging of the neighboring anatomic structures in the upper abdomen.

16. The appropriate transducer depends on the patient’s body habitus and size
The average adult abdomen usually requires a 3.5MHz

17. The basic instrumentation should be adjusted in the following parameters :
Time gain compensation
Overall gain
Transducer frequency and type
Depth and focus

18. Sagittal image of gallbladder

19. Gallbladder and Biliary System
Normal size of gallbladder:
7~9cm in length ;
3~4cm in width;
Wall thickness : 2~3mm
Normal size of bile ducts :
right /left intrahepatic duct just to proximal CHD: 2-3mm ；
CBD:≥8mm =dilated

20. Sagittal image of liver /right kidney
The normal liver parenchyma should have a softer , more homogenerous texture than the dense medulla and hypoechoic renal cortex

21. Transverse Scan Plane
Multiple transverse scans are made across the upper abdomen to record specific areas of the liver. The transducer should be angled in a steep cephalic direction to be as parallel to the diaphragm as possible.

22. Transverse Scan Plane
The transducer is then directed slightly inferior to record the left portal vein as it flows into the left lobe of the liver.

23. The gallbladder may be seen in this scan as an anechoic structure medial to the right lobe and anterior to the right kidney.

24. Common bile duct
Diameter <0.8cm

25. Sonographic Evaluation of The Liver
Adequate scanning technique demands that each patient be examined with the following assessment
The size of the liver in the longitudinal plane
The attenuation of the liver parenchyma
Liver texture
The presence of hepatic vascular structures, ligaments ,and fissures

26. Pathology of the Liver
Evaluation of the liver parenchyma includes the assessment of its size , configuration, homogeneity , and contour.

27. The Normal attenuation of the liver parenchyma Normal: Liver texture=homogeneous Assessment of its size , configuration, homogeneity , and contour

28. Suggested Readings
David Sutton’s Radiology

29. Assignment
Two students will be selected for assignment

30. Question
Describe the vascular supply of the liver.

31. Thank you for your attention!