Oblique Scanning of the Left Hepatic Lobe and Caudate Lobe

Oblique liver section • External lobe • Oblique approach

Scanning Method

The patient should be fasted for 8–12 hours and examined in the supine position. Place the ultrasound probe obliquely in the subxiphoid region and angle it toward the left upper abdomen. Adjust the probe orientation, angle, depth, and pressure to obtain a clear oblique section of the left hepatic lobe and caudate lobe. The scan should demonstrate the relevant hepatic and vascular landmarks, including the left portal vein, inferior vena cava (IVC), caudate lobe, and adjacent hepatic structures.

Key scanning point: Begin from the subxiphoid region with the probe oriented obliquely toward the left upper abdomen. Adjust the probe angle and pressure to clearly demonstrate the left hepatic lobe and caudate lobe. Optimize the depth and gain to maintain a well-defined hepatic parenchymal view and identify the caudate lobe in relation to the IVC and portal venous structures.

Ultrasound Image

Figure 1.1 Oblique sonographic section of the left hepatic lobe and caudate lobe obtained through the subxiphoid approach, demonstrating the left portal vein (LPV), inferior vena cava (IVC), aorta (Ao), caudate lobe (CL), and adjacent hepatic vascular landmarks.

Anatomical / Scanning Diagram

Figure 1.2: Diagram showing the probe orientation, oblique scanning plane, left hepatic lobe, and caudate lobe, with the relevant labeled hepatic and vascular anatomical landmarks.

Section Structure

The principal structures demonstrated in this plane include the left hepatic lobe and caudate lobe, with the QL, LPV, IVC, VL, and Ao serving as important anatomical landmarks. The numbered structures 1, 2, and 3 are also identified according to the reference diagram.

Structures to identify

• The enternal branch of left portal vein (3)
• Quadrate lobe (QL)
• Left portal vein (LPV)
• Inferior vena cava (IVC)
• Umbilical and sagittal section of left portal vein (1)
• The external superior branch of the left portal vein (2)
• Venous ligament / ligamentum venosum (VL)
• Caudate lobe (CL)
• Aorta (Ao)
• Hepatic parenchyma

Abbreviations Used in the Figure

Short form	Full form	Identification
3	Numbered structure	The enternal branch of left portal vein
QL	Quadrate lobe	Quadrate lobe of the liver.
LPV	Left portal vein	Left portal venous branch within the hepatic parenchyma.
IVC	Inferior vena cava	Major venous landmark posterior to the liver.
1	Numbered structure	Umbilical and sagittal section of left portal vein.
2	Numbered structure	The external superior branch of the left portal vein.
VL	Venous ligament	Ligamentum venosum between the left hepatic lobe and caudate lobe.
CL	Caudate lobe	Caudate lobe located adjacent to the IVC.
Ao	Aorta	Major arterial landmark posterior to the liver.

Measuring Method and Normal

In this oblique subxiphoid plane, measurements may be obtained when clinically indicated. The IVC, Ao, and selected vascular structures should be assessed only when clearly visualized and using an appropriate standardized caliper technique.

Measurement	Caliper method	Reference / interpretation
IVC	Measure the internal diameter perpendicular to the vessel's long axis when appropriate.	Interpret according to respiratory phase and clinical context.
Ao	Measure the aortic diameter at the appropriate level with calipers positioned across the vessel.	Interpret according to the measurement site and clinical context.

Measurement note: Keep the target structure clearly visualized and avoid including adjacent structures in the measurement.

The Clinical Application Value

This oblique subxiphoid plane provides an important view of the left hepatic lobe and caudate lobe and demonstrates the QL, LPV, IVC, VL, CL, and Ao, together with the numbered structures 1, 2, and 3.

• Demonstration of the left hepatic lobe.
• Identification of the quadrate lobe (QL).
• Visualization of the left portal vein (LPV).
• Recognition of the IVC as a posterior vascular landmark.
• Identification of the venous ligament (VL).
• Identification of the caudate lobe (CL).
• Identification of the aorta (Ao).
• Recognition of numbered structures 1, 2, and 3.
• Assessment of hepatic parenchymal echogenicity and contour.

Quick Scanning Checklist

1	Fast the patient for 8–12 hours when appropriate.
2	Position the patient supine.
3	Place the probe obliquely in the subxiphoid region.
4	Obtain the oblique view of the left hepatic lobe.
5	Identify QL and CL.
6	Identify the LPV and VL.
7	Identify the IVC and Ao as posterior vascular landmarks.
8	Identify the numbered structures 1, 2, and 3.
9	Assess hepatic contour and parenchymal echogenicity.

Diagnostic Pathology

This oblique subxiphoid view can assist in evaluating hepatic and vascular abnormalities. Assess the QL, LPV, IVC, VL, CL, and Ao together with the surrounding hepatic anatomy and the numbered structures 1, 2, and 3.

Key Sonographic Findings

• Hepatomegaly: Increased hepatic size with altered contour or morphology.
• Hepatic steatosis: Increased hepatic echogenicity with reduced visualization of deeper structures.
• Cirrhotic change: Coarse echotexture, irregular contour, and altered hepatic architecture.
• Focal liver lesion: Focal abnormality differing in echogenicity or architecture from the surrounding hepatic parenchyma.
• Caudate lobe enlargement: Enlargement of the CL, particularly in chronic liver disease.
• Quadrate lobe abnormality: Altered size, contour, or echotexture involving the QL.
• Portal venous abnormality: Altered caliber, thrombosis, or abnormal Doppler flow involving the LPV.
• IVC abnormality: Altered caliber, narrowing, compression, or intraluminal abnormality involving the IVC.
• Venous ligament abnormality: Abnormal appearance or adjacent structural alteration involving the VL.
• Aortic abnormality: Abnormal caliber, wall irregularity, atherosclerotic change, or aneurysmal dilatation involving the Ao.
• Portal hypertensive changes: Enlarged venous structures or collateral vessels may be identified in the appropriate clinical setting.

Diagnostic note: Interpret abnormal findings together with the complete abdominal ultrasound examination, Doppler assessment, clinical history, and laboratory findings. A single sonographic finding should not be used in isolation to establish a diagnosis.

Oblique Scanning of the Left External Hepatic Lobe

Oblique liver section • External lobe • Oblique approach

Scanning Method

The patient should be fasted for 8–12 hours and examined in the supine position. Place the ultrasound probe obliquely in the subxiphoid region and angle it toward the left external hepatic lobe. Adjust the probe orientation, angle, depth, and pressure to obtain a clear oblique section of the left hepatic lobe and demonstrate the relevant hepatic and vascular landmarks.

Key scanning point: Begin from the subxiphoid region with the probe oriented obliquely toward the left upper abdomen. Adjust the probe angle to clearly demonstrate the left external hepatic lobe and its adjacent anatomical structures while maintaining a well-defined hepatic parenchymal view.

Ultrasound Image

Figure 1.1 Oblique section of the left external hepatic lobe on subxiphoid scanning. Insert the corresponding ultrasound image in the space above.

Anatomical / Scanning Diagram

Figure 1.2: Diagram space showing the probe orientation, oblique scanning plane, left external hepatic lobe, and labeled anatomical landmarks.

Section Structure

The principal structures demonstrated in this plane are the left hepatic lobe and caudate lobe, with the stomach, pancreas, splenic vein, venous ligament, aorta, and inferior vena cava serving as important adjacent anatomical landmarks.

Structures to identify

• Left hepatic lobe (LL)
• Numbered structure (1)
• Caudate lobe (CL)
• Inferior vena cava (IVC)
• Stomach (ST)
• Pancreas (P)
• Splenic vein (SpV)
• Venous ligament / ligamentum venosum (VL)
• Aorta (Ao)
• Hepatic parenchyma

Abbreviations Used in the Figure

Short form	Full form	Identification
LL	Left lobe	Left hepatic lobe.
1	Numbered structure	Reference structure indicated by number 1.
CL	Caudate lobe	Caudate lobe adjacent to the IVC.
IVC	Inferior vena cava	Major venous landmark posterior to the liver.
ST	Stomach	Gastric structure adjacent to the liver.
P	Pancreas	Pancreatic structure adjacent to the hepatic region.
SpV	Splenic vein	Venous structure coursing posterior to the pancreas.
VL	Venous ligament	Ligamentum venosum between the left lobe and caudate lobe.
Ao	Aorta	Major arterial landmark posterior to the liver.

Measuring Method and Normal

In this oblique subxiphoid plane, measurements may be obtained when clinically indicated. The IVC, SpV, or Ao may be assessed when clearly visualized, using an appropriate standardized caliper technique.

Measurement	Caliper method	Reference / interpretation
IVC	Measure the internal diameter perpendicular to the vessel's long axis when appropriate.	Interpret with respiratory phase and clinical context.
Ao	Measure the aortic diameter at the appropriate level with calipers positioned across the vessel.	Interpret according to the measurement site and clinical context.

Measurement note: Keep the target structure clearly visualized and avoid including adjacent structures in the measurement.

The Clinical Application Value

This plane provides an oblique view of the left external hepatic lobe and demonstrates important adjacent structures including the CL, IVC, ST, P, SpV, VL, and Ao.

• Demonstration of the left hepatic lobe (LL).
• Identification of the caudate lobe (CL).
• Recognition of the IVC as a posterior vascular landmark.
• Visualization of the stomach (ST) and pancreas (P).
• Identification of the splenic vein (SpV).
• Recognition of the venous ligament (VL).
• Identification of the aorta (Ao).
• Assessment of hepatic parenchymal echogenicity and contour.

Quick Scanning Checklist

1	Fast the patient for 8–12 hours when appropriate.
2	Position the patient supine.
3	Place the probe obliquely in the subxiphoid region.
4	Obtain the oblique view of the left hepatic lobe.
5	Identify LL and CL.
6	Identify ST, P, SpV, VL, and Ao.
7	Identify the IVC as a posterior vascular landmark.
8	Assess hepatic contour and parenchymal echogenicity.

Diagnostic Pathology

This oblique subxiphoid view can assist in identifying hepatic, vascular, gastric, pancreatic, and splenic venous abnormalities. Evaluate the LL, CL, IVC, ST, P, SpV, VL, and Ao together with the surrounding anatomy.

Key Sonographic Findings

• Hepatomegaly: Increased hepatic size with altered contour or morphology.
• Hepatic steatosis: Increased hepatic echogenicity with reduced visualization of deeper structures.
• Cirrhotic change: Coarse echotexture, irregular contour, and altered hepatic architecture.
• Focal liver lesion: Focal abnormality differing in echogenicity or architecture from the surrounding liver.
• Caudate lobe enlargement: Enlargement of the CL, particularly in chronic liver disease.
• IVC abnormality: Altered caliber, narrowing, compression, or intraluminal abnormality.
• Splenic vein abnormality: Altered caliber, thrombosis, or abnormal Doppler flow involving the SpV.
• Pancreatic abnormality: Enlargement, altered echogenicity, or focal lesion involving the P.
• Gastric abnormality: Abnormal gastric wall thickening, distension, or adjacent mass effect when adequately visualized.
• Aortic abnormality: Abnormal caliber, wall irregularity, atherosclerotic change, or aneurysmal dilatation involving the Ao.
• Portal hypertensive changes: Enlarged venous structures or collateral vessels may be seen in the appropriate clinical setting.

Diagnostic note: Interpret abnormal findings together with the complete abdominal ultrasound, Doppler assessment, clinical history, and laboratory findings. A single sonographic finding should not be used in isolation to establish a diagnosis.