Longitudinal Scanning of the Intrapancreatic Portion and End Part of the Common Bile Duct by the Right Subcostal and Right Upper Abdomen
Scanning Method
The patient should preferably be fasted for 8–12 hours and examined in the supine position. Place the ultrasound probe in the right subcostal region and right upper abdomen. Direct the probe to obtain a longitudinal view of the intrapancreatic portion and end part of the common bile duct (CBD). Adjust the probe angle, rotation, depth, and patient position as required to follow the distal CBD toward its termination.
Ultrasound Image
Figure 1.1: Longitudinal right upper abdominal sonographic view demonstrating the right lobe of the liver (RL), gallbladder (GB), portal vein (PV), pylorus (PH), common bile duct (CBD), inferior vena cava (IVC), and duodenum (Du).
Anatomical / Scanning Diagram
Figure 1.2: Reference sonographic image showing the scanning orientation and the anatomical relationship of the distal common bile duct to the liver, gallbladder, portal vein, pylorus, inferior vena cava, and duodenum.
Section Structure
The principal structures demonstrated in the supplied image are the right lobe of the liver (RL), gallbladder (GB), portal vein (PV), pylorus (PH), common bile duct (CBD), inferior vena cava (IVC), and duodenum (Du). These structures provide important anatomical landmarks for following the intrapancreatic and terminal portions of the CBD.
Structures to identify
- Right lobe of the liver (RL)
- Gallbladder (GB)
- Portal vein (PV)
- Pylorus (PH)
- Common bile duct (CBD)
- Inferior vena cava (IVC)
- Duodenum (Du)
- Intrapancreatic portion of the CBD
- Terminal/end part of the CBD when adequately visualized
- Adjacent pancreatic and upper abdominal structures
Abbreviations Used in the Figure
| Abbreviation | Full form | Identification |
|---|---|---|
| RL | Right Lobe of Liver | Right hepatic lobe/parenchyma demonstrated in the scanning field. |
| GB | Gallbladder | Gallbladder visualized adjacent to the right hepatic lobe. |
| PV | Portal Vein | Portal venous structure serving as an important hepatobiliary landmark. |
| PH | Pylorus | Pyloric portion of the stomach visualized near the hepatobiliary region. |
| CBD | Common Bile Duct | Extrahepatic biliary duct and principal target of this scanning view. |
| IVC | Inferior Vena Cava | Major venous landmark posterior to the liver and upper abdominal structures. |
| Du | Duodenum | Duodenal structure adjacent to the distal common bile duct. |
Abbreviation note: The abbreviations are taken directly from the labels visible in the supplied ultrasound image: RL, GB, PV, PH, CBD, IVC, and Du.
Measuring Method and Normal
When clinically indicated, assess the intrapancreatic and terminal common bile duct in a clearly visualized longitudinal and transverse plane. Place the calipers across the duct lumen at an appropriate site and avoid including surrounding pancreatic tissue, bowel wall, or adjacent vascular structures. Interpretation should consider the patient's clinical context and the remainder of the biliary examination.
| Measurement | Caliper method | Reference / interpretation |
|---|---|---|
| Intrapancreatic CBD | Measure the clearly visualized duct lumen perpendicular to its long axis whenever possible. | Document the caliber together with the sonographic appearance and clinical context. |
| End / Terminal CBD | Measure the visible terminal duct without including adjacent duodenal wall or pancreatic tissue. | Assess for focal dilatation, narrowing, intraluminal abnormality, or nonvisualization. |
Measurement note: Confirm the CBD lumen before measurement and distinguish it from the adjacent PV, pancreatic tissue, and Du. An oblique section may falsely increase the apparent duct diameter.
The Clinical Application Value
This right subcostal and right upper abdominal approach provides a useful longitudinal view for assessing the intrapancreatic portion and end part of the common bile duct. It permits assessment of the CBD in relation to the portal vein (PV), duodenum (Du), pylorus (PH), gallbladder (GB), and adjacent hepatic anatomy.
- Demonstration of the intrapancreatic portion of the CBD.
- Visualization of the terminal/end part of the CBD when adequately demonstrated.
- Assessment of CBD caliber.
- Assessment for distal biliary obstruction.
- Evaluation for intraductal calculus or sludge when visible.
- Assessment of the relationship of the CBD to the duodenum (Du).
- Recognition of the portal vein (PV) as an anatomical landmark.
- Assessment of the gallbladder (GB) and proximal biliary system.
- Recognition of the IVC as a posterior vascular landmark.
Quick Scanning Checklist
| 1 | Fast the patient for 8–12 hours when appropriate. |
| 2 | Position the patient supine. |
| 3 | Place the probe at the right subcostal/right upper abdominal region. |
| 4 | Adjust the probe to obtain a longitudinal view of the distal CBD. |
| 5 | Identify the RL as the hepatic landmark. |
| 6 | Identify the PV and use it as an important anatomical landmark. |
| 7 | Identify the CBD and follow it toward its intrapancreatic and terminal portions. |
| 8 | Identify the Du adjacent to the distal CBD. |
| 9 | Identify the GB, PH, and IVC when visualized. |
| 10 | Assess the CBD for dilatation, narrowing, intraluminal echoes, or other abnormalities. |
| 11 | Measure the CBD only when clearly visualized and with appropriate caliper placement. |
| 12 | Complete the examination with additional hepatobiliary and pancreatic views when clinically indicated. |
Diagnostic Pathology
The longitudinal right subcostal/right upper abdominal view can assist in evaluating the intrapancreatic and terminal common bile duct. The CBD should be assessed together with the gallbladder, intrahepatic biliary tree, portal structures, pancreas, and duodenum.
Key Sonographic Findings
- Distal CBD dilatation: Increased caliber of the intrapancreatic or terminal CBD.
- Distal biliary obstruction: CBD dilatation proximal to a possible obstructing process.
- Choledocholithiasis: Echogenic intraluminal focus within the CBD that may demonstrate posterior acoustic shadowing.
- Biliary sludge: Low-level or echogenic material within the CBD lumen when adequately visualized.
- CBD stricture: Focal narrowing of the distal duct with possible upstream biliary dilatation.
- Terminal CBD abnormality: Focal irregularity, narrowing, or altered appearance of the duct near its distal termination.
- Pancreatic-region abnormality: Abnormal tissue or mass effect surrounding the intrapancreatic CBD that may alter its course or caliber.
- Duodenal-related limitation: Bowel gas or duodenal contents may limit visualization of the terminal CBD.
- Nonvisualization of the terminal CBD: Inadequate visualization should be interpreted in relation to bowel gas, patient habitus, respiratory movement, and scanning plane.
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