Scanning Planes

Scanning Planes in Liver Ultrasound

In liver ultrasound imaging, different scanning planes are used to comprehensively evaluate the liver's anatomy, vasculature, and any pathological changes. Here’s a concise overview of the scanning planes in liver ultrasound:
1. Transverse (Axial) Plane

• Orientation: The transducer is placed horizontally across the upper abdomen.
• View:Cross-sectional view of the liver.
• Structures Visualized:
• Right and left lobes of the liver.
• Portal vein in its transverse section ("Mickey Mouse sign").
• Gallbladder (if included).
• Inferior vena cava (IVC).

2. Sagittal (Longitudinal) Plane

• Orientation:The transducer is oriented vertically along the midline or right upper quadrant.
• View: Longitudinal view of the liver.
• Structures Visualized:
• Liver span (craniocaudal length).
• Relationship to the kidney (e.g., "liver-kidney interface").
• IVC in longitudinal section.

3. Subcostal Plane

• Orientation:Transducer is angled upward under the costal margin.
• Use:Often used in deep inspiration to improve liver visualization by moving the liver below the rib cage.
• Structures Visualized:
• Anterior liver segments.
• Hepatic veins and diaphragm.

4. Intercostal Plane

• Orientation:Transducer is placed between the ribs in the right upper quadrant.
• Use:Helps avoid rib shadows.
• Structures Visualized:
• Superior liver segments.
• Diaphragmatic surface.
• Right hepatic lobe.

5. Coronal Plane

• Orientation: Transducer placed in the mid or anterior axillary line, scanning vertically.
• View: Vertical slice from side to side.
• Structures Visualized:
• Lateral and medial segments.
• Hepatic veins draining into the IVC.

6. Oblique Planes

• Orientation:Angled transducer positioning tailored to follow vascular pathways or segmental anatomy.
• Use:For targeted views of:
• Portal vein bifurcation.
• Hepatic veins.
• Lesions.

Key Tips for Liver Ultrasound Scanning

• Patient Position:Supine, left lateral decubitus, or upright to optimize visualization.
• Breathing Technique: Deep inspiration enhances liver window by displacing the liver downward.
• Acoustic Window:Use the right kidney or full bladder (if scanning caudally) as acoustic windows.

Technical Assessment

Technical Assessment: Liver Ultrasound

A technical assessment for liver ultrasound involves evaluating the image quality, anatomical coverage, and sonographic technique to ensure accurate diagnosis and documentation. This is typically done by the sonographer or radiologist and is often included in structured reporting. Below is a sample technical assessment section and the key points usually covered:
1. Study Type:

• Complete abdominal ultrasound
• Focused liver ultrasound
• ollow-up / Targeted liver exam
• Doppler liver ultrasound

2. Image Quality:

• Adequate / Good / Suboptimal
• Acoustic window: Clear / Limited due to bowel gas, body habitus, or motion artifact
• Liver parenchyma: Well visualized / Poorly visualized

3. Structures Evaluated:

• Liver size and contour
• Liver echotexture (homogeneous/heterogeneous, fatty infiltration, cirrhotic changes)
• Intrahepatic bile ducts (normal/dilated)
• Hepatic vessels (portal veins, hepatic veins, IVC)
• Gallbladder and biliary tree
• Focal liver lesions (if any)
• Right kidney and Morrison’s pouch (for reference)

4. Doppler Assessment (if performed):

• Hepatic artery and portal vein flow direction and velocity
• Liver echotexture (homogeneous/heterogeneous, fatty infiltration, cirrhotic changes)
• Hepatic venous waveform
• Portal hypertension signs (e.g., collaterals, reversed flow)

Technical Assessment

Transducer Selection

1. Transducer Selection

• Curved Array Transducer (2–5 MHz):Primary probe for abdominal imaging; allows deep penetration with wide field of view suitable for liver evaluation.
• Linear Array Transducer (5–12 MHz):Used for evaluating superficial lesions in thin patients or for guiding interventional procedures.
• Phased Array Transducer:Occasionally used in intercostal views or in critically ill patients where access is limited.

2. Imaging Modes Utilized

• 2D Grayscale Imaging:Standard for evaluating liver size, contour, parenchymal echotexture, lesions, biliary ducts, and vessels.
• Color Doppler Imaging:Evaluates flow in the portal vein, hepatic veins, hepatic artery, and any vascular lesions. Helps identify flow direction and turbulence.
• Spectral Doppler:Used for waveform analysis in hepatic veins (triphasic), portal vein (hepatopetal monophasic), and hepatic artery (resistive index).
• Elastography (if available):Strain Elastography or Shear Wave Elastography to assess liver stiffness in suspected fibrosis or cirrhosis.
  Provides quantitative kPa or m/s values.
• Contrast-Enhanced Ultrasound (CEUS):Performed using microbubble contrast agents to characterize liver lesions (e.g., hemangioma, HCC, metastases). Requires low MI (mechanical index) settings and dual-screen for contrast dynamics.

3. Machine Settings and Optimization

• Depth and Gain:Adjusted to ensure full liver coverage with optimal parenchymal contrast. Time gain compensation (TGC) balanced from near to far field.
• Focal Zones:Positioned at or just below the area of interest to maximize lateral resolution.
• Dynamic Range:Tuned for optimal contrast resolution to differentiate lesions from normal liver tissue.
• Harmonic Imaging:Enabled to enhance lesion detectability and reduce artifacts in obese patients or deeper organs.g:
• Doppler Settings:
• Color box size and angle minimized to maximize frame rate.
• PRF (Pulse Repetition Frequency): Set appropriately for expected flow velocities.
• Wall filters: Lowered for detecting slow venous flow in portal vein.
• Angle correction: Applied when measuring velocities (>60° avoided if possible).
• Elastography Calibration:Performed with patient in breath-hold, right lobe through intercostal space, avoiding large vessels.
• CEUS Optimization:
• Low MI settings (e.g., 0.08–0.2)
• Real-time dual-imaging for contrast tracking
• High frame rate, low persistence

Ultrasound Transducer Types

Type	Frequency (MHz)	Use
Curvilinear (Convex)	2–5 MHz	Standard transducer for adult abdominal imaging. Provides deep penetration and a wide field of view.
Linear Array	5–12 MHz	Used for high-resolution imaging of superficial structures, pediatric patients, or focal lesions in thin patients.
Phased Array	2–4 MHz	Occasionally used in intercostal views or limited acoustic windows.

Technical Assessment

Imaging Modes

Ultrasound Imaging Modes

Mode	Purpose
B-mode (Brightness Mode)	Main mode for liver parenchyma, contour, and lesion visualization.
Color Doppler	Assesses blood flow in hepatic vessels (e.g., portal vein, hepatic veins).
Spectral Doppler	Measures velocity and direction of flow in specific vessels.
Power Doppler	More sensitive than color Doppler for detecting low-velocity flow (e.g., portal hypertension, small vessels).
Elastography (optional)	Assesses liver stiffness (fibrosis staging).
Contrast-Enhanced Ultrasound (CEUS)	For detailed lesion characterization (requires contrast agent).

Technical Assessment

Machine Settings and Optimization

To ensure diagnostic-quality images, the following settings should be carefully adjusted:
a. Depth

• Set so the liver fills most of the screen without cutting off posterior segments.
• Keep the area of interest centered.

b. Gain

• Adjust to enhance overall brightness without overexposing the image.
• Time-Gain Compensation (TGC): Adjust for even brightness from near to far field.

c. Focus

• Position the focal zone at or just below the area of interest (e.g., lesion or vessel).

d. Dynamic Range

• A moderate dynamic range provides a balance between contrast and detail.
• Narrow range: High contrast (good for lesion detection).
• Wide range: More grayscale detail (good for parenchymal texture).

e. Frame Rate

• High frame rate preferred, especially when assessing motion or blood flow.
• Adjust sector width and depth to optimize.

f. Doppler Settings

• Scale (PRF):Set appropriately to avoid aliasing.
• Gain:Increase until background noise appears, then slightly reduce.
• Wall filter: Lower settings for slow venous flow.
• Angle correction:Keep angle < 60° for accurate velocity measurement.

Additional Tips

• Ensure the patient fasts for 6–8 hours to reduce bowel gas and improve visualization.
• Use gel liberally for better acoustic coupling.
• Reposition the patient (e.g., left lateral decubitus) if rib shadowing or poor windows occur.

Patient Preparation

Patient Preparation for Liver Ultrasound

Proper preparation improves the accuracy of a liver ultrasound by reducing bowel gas and enhancing sound wave penetration. Here are the standard guidelines:
1. Fasting Requirements

• Fasting Duration:6–8 hours before the exam.
• Reason: Reduces bowel gas and allows the gallbladder to remain distended for better visualization of adjacent liver structures.

2. Medications

• Patients may continue regular medications with a small amount of water, unless otherwise instructed by their physician.

3. Hydration

• Dvoid excessive fluid intake before the exam (especially carbonated drinks), as it may increase bowel gas and obscure liver structures.

4. Dietary Instructions
Diabetic patients: TMay need individualized instructions to balance fasting with glucose control. Emergency cases: Preparation may be limited or skipped based on clinical urgency.
5. What to Wear:

• Wear comfortable, loose-fitting clothing.
• You may be asked to change into a gown during the procedure.

6. During the Exam:

• The procedure usually takes 15–30 minutes.
• A warm gel will be applied to your abdomen, and a transducer will be moved over the area.
• The exam is non-invasive and painless.

7. After the Exam:

• You may resume normal activities and diet unless otherwise instructed.
• Your results will be sent to your doctor for review.

Positioning & Techniques

Positioning Techniques for Liver Ultrasound

Proper positioning is crucial for optimal visualization of liver anatomy and pathology during sonographic examination. Here are standard and advanced positioning techniques used in liver ultrasound:
1. Supine Position (Standard)

• Patient lies flat on their back.
• Most common starting position for liver ultrasound.
• Transducer is placed subcostally or intercostally in the right upper quadrant.
• Used to assess the entire liver, portal and hepatic veins, and surrounding structures.

2. Left Posterior Oblique (LPO) or Left Lateral Decubitus (LLD)

• Patient lies on their left side.
• Allows the liver to fall forward, increasing the acoustic window between the ribs.
• Enhances visualization of the right lobe, especially for obese patients or those with rib shadowing.
• Useful for evaluating the right kidney-liver interface and posterior segments of the right lobe.

3. Right Posterior Oblique (RPO) or Right Lateral Decubitus (RLD)

• Patient lies on their right side.
• Less commonly used but helpful for left lobe assessment.
• May improve access to caudate lobe and ligamentum venosum.

4. Sitting or Upright Position

• Patient sits upright or leans forward.
• Useful when bowel gas or obesity obscures liver visualization.
• Gravity assists in moving bowel loops inferiorly and liver superiorly.

5. Deep Inspiration Technique

• Instruct patient to take and hold a deep breath.
• Moves the liver inferiorly, improving access to the subcostal and intercostal windows.
• Enhances Doppler flow assessment of hepatic vessels.

6. Subcostal and Intercostal Approaches

• Subcostal: Probe angled under the costal margin.
• Intercostal: Probe placed between the ribs, usually in coronal or oblique orientation.
• Intercostal scanning helps avoid rib shadowing and visualize deeper segments.

7. Prone or Semi-Prone Position

• Rarely used, but may help assess posterior liver lesions or in interventional procedures.

8. Arm Position

• Ask patient to raise their right arm above the head.
• This stretches the intercostal spaces and improves access to the right upper quadrant

Summary Table: Liver Ultrasound Positioning Techniques

Position	Usefulness
Supine	Standard view of liver
LLD (Left Lateral Decubitus)	Right lobe access, reduces rib shadow
RLD (Right Lateral Decubitus)	Better left lobe view
Upright	Displaces bowel gas
Deep Inspiration	Brings liver below rib cage
Subcostal/Intercostal	Targets deeper/posterior segments

Patient History and Consent

Liver Ultrasound - Patient History & Consent

Patient History and Consent for Liver Ultrasound

Full Name: Age / Sex: Clinical Indication: Relevant Medical History: Surgical History: Current Symptoms:

Consent Statement:

I understand that a liver ultrasound is a non-invasive imaging procedure using sound waves to examine the liver. It is painless and involves no radiation exposure. I have had the opportunity to ask questions and consent to proceed with the procedure.

I have read and agree to the above statement.

Reporting and Documentation of liver ultrasound

Sonographical findings of liver

Size: Normal / Enlarged / Reduced (e.g., liver length at midclavicular line: XX cm).


Echotexture: Normal / Increased (suggestive of fatty infiltration) / Heterogeneous (suggestive of cirrhosis or other pathology).

Echogenicity: Normal / Increased / Decreased.

Contour: Smooth / Irregular / Nodular.

Lesions/Masses: Presence of any focal lesions (e.g., cysts, hemangiomas, metastases) – describe size, location, echogenicity, borders, vascularity (with Doppler).
1. Echogenicity Assessment of liver lesions

Type of Echogenicity	Description	Common Lesion Examples	Interpretation
Anechoic	Completely black, no internal echoes	Simple cyst, bile duct, vascular structures	Fluid-filled, benign
Hypoechoic	Darker than liver parenchyma	Abscess, metastasis, HCC (early), lymphoma	Suspicious, may be solid or inflammatory
Isoechoic	Similar echogenicity to surrounding liver	HCC, hemangioma	Can blend into background—needs Doppler or contrast
Hyperechoic	Brighter than liver parenchyma	Hemangioma, focal fat, calcification, metastasis	Often benign, but not always
Mixed echogenicity (heterogeneous)	Both hypoechoic and hyperechoic areas	Necrotic tumors, complex cysts, metastasis	Suggests complex lesion—needs further workup

Anechoic Lesion
• Appearance: Well-defined, black with posterior enhancement
• Examples: Simple cyst, biliary cyst
• Significance: Typically benign

Hypoechoic Lesion
• Appearance: Darker than liver, poorly marginated or irregular
• Examples: Liver abscess, metastases, early HCC, lymphoma
• Significance: Needs Doppler/CEUS/biopsy for confirmation

Isoechoic Lesion
• Appearance: Same echogenicity as liver → “invisible” on grayscale
• Examples: HCC, hemangioma (sometimes)
• Tips: Look for capsular bulge, distortion, or use Doppler/CEUS

Hyperechoic Lesion
• Appearance: Brighter than normal liver tissue
• Examples: Hemangioma (most common), focal fatty change, calcified metastases
• Clues: Hemangioma often shows posterior enhancement and peripheral nodular enhancement on CEUS

Mixed Echogenic Lesion
• Appearance: Irregular internal echoes, septations, solid + cystic parts
• Examples: Necrotic metastases, hepatoblastoma, complex abscess
• Red Flag: Always needs further investigation

Clinical Interpretation Table

Lesion Type	Echogenicity	Common Diagnosis	Diagnostic Step
Simple cyst	Anechoic	Benign cyst	No further workup if classic
Solid round mass	Hypoechoic	HCC, metastasis	Doppler, CEUS, Biopsy
Bright lesion	Hyperechoic	Hemangioma, fat focus	CEUS or MRI for certainty
Mixed pattern	Heterogeneous	Necrotic tumor, abscess	Biopsy or advanced imaging
Invisible lesion	Isoechoic	Isoechoic HCC	CEUS or MRI


2. Border Assessment of liver lesions
Assessment of lesion borders on ultrasound is a crucial component in the evaluation of liver pathology. The morphology and definition of lesion margins offer valuable diagnostic insights that help distinguish between benign and malignant entities.

• Well-defined, smooth borders typically indicate benign lesions, such as simple cysts or hemangiomas.

• Shape & Echogenicity: Hemangiomas often appear as small (<3 cm) uniformly hyperechoic lesions These bright lesions “stand out” clearly against the liver parenchyma.
• Borders: They exhibit smooth, sharp margins, distinguishing them sharply from surrounding tissue—a hallmark of benign lesions
• Posterior Enhancement: Frequently seen as increased brightness deep to the lesion, known as posterior acoustic enhancement
• Doppler Flow: Often lacks visible blood flow on color or power Doppler due to its slow-flow vascular nature
• if the lesion is larger than 3 cm, shows atypical features, or the patient has high-risk factors, contrast-enhanced ultrasound (CEUS) or further imaging like CT/MRI may be recommended for confirmation
• Ill-defined or irregular borders often suggest malignant or infiltrative lesions, including hepatocellular carcinoma (HCC) or cholangiocarcinoma.

• Classic simple liver cyst: Appears as a sharply demarcated, anechoic (completely black) round lesion with a smooth, thin wall on ultrasound
• The images above clearly show smooth margins and a thin cyst wall, indicating a benign nature without septations, mural nodularity, or complex features
• Anechoic interior: Lesion appears completely dark, typical of fluid content .
• Smooth, thin walls: Clearly defined, separating the cyst from liver tissue
• Posterior acoustic enhancement: Increased brightness behind the cyst due to sound waves passing through fluid
• No internal septations or solid components: Helps differentiate simple cysts from complex or parasitic lesions
• A thin peripheral halo or rim is considered a classic feature of HCC or metastatic lesions, warranting further evaluation.

Image 1: Small HCC (<2 cm) presenting a thin hypoechoic rim around a hypoechoic nodule—this “halo” represents the fibrous capsule

Image 2: Larger HCC with a distinct peripheral halo—along with lateral shadow and posterior enhancement, these features are hallmark ultrasound signs of HCC >20 mm

Image 3: show a heterogeneous hypoechoic lesion with a thin rim—readers will notice the halo and accompanying mosaic pattern typical of HCC.

Image 4: A heterogenous lesion with a clear hypoechoic rim (halo sign) observed in a cirrhotic liver—both B‑mode and color Doppler confirm the classic halo morphology.
• Thickened, nodular, or multiloculated borders may point toward necrotic tumors, abscesses, or parasitic cysts like hydatid disease.

Image 1: Complex sonographic pattern in a suspected malignant focal liver lesion. The thick irregular rim surrounds a heterogeneous center, suggesting necrosis and solid tumor components. Image 2: A large multilocular cystic mass with thick walls and internal heterogeneity, highly suggestive of abscess or necrotic tumor.
• Capsular bulging suggests mass effect and is often seen in large or exophytic lesions.


Feature	Capsular Bulging Lesion	Non-Bulging Simple Cyst
Capsule contour	Protrudes outward, causing a visible bulge	Remains smooth, no bulging
Lesion location	Subcapsular / exophytic	Intrahepatic
Appearance	Solid or complex mass, may stretch capsule	Anechoic, fluid-filled, smooth-walled
Clinical concern	Higher likelihood of large tumor or malignancy	Benign; asymptomatic, incidental finding





Border Type	Ultrasound Description	Possible Diagnosis	Next Step
Well-defined, smooth	Sharp margins, clear separation from liver parenchyma	Simple cyst, hemangioma, metastasis	Often benign; confirm with CEUS/MRI if needed
Irregular or ill-defined	Blurry or spiculated edges blending into liver tissue	HCC, cholangiocarcinoma, infiltrative lesions	Require Doppler, CEUS, biopsy
Thin peripheral halo	Hypoechoic rim around lesion ("halo sign")	Often HCC or metastasis	Suggests malignancy; further imaging
Thick or nodular rim	Heterogeneous or complex border with nodularity	Necrotic tumor, abscess	CEUS/CT for clarification
Multiloculated border	Multiple septations or compartments within lesion	Cystic metastases, hydatid cyst	Correlate with serology/CT
Capsule bulging	Lesion causing bulge in liver contour	Large hemangioma or exophytic mass	Evaluate mass effect with CT/MRI

Vasculature: Evaluate portal vein, hepatic veins, hepatic artery (flow direction, patency, velocity if needed).
Biliary Tree: Intrahepatic ducts – dilated / not dilated.
Additional Findings


Additional Findings .
Ascites: Not present / Present (quantify or localize if possible).
Lymphadenopathy: None detected / Present (describe location and size).
Adjacent Organs: (e.g., pancreas, right kidney) – mention any incidental findings.

Impression / Conclusion


Normal liver ultrasound: No evidence of sonological abnormalities.
Abnormal Findings: For example-
Features suggestive of hepatic steatosis
Recommendations

Descriptive Terminology for Liver Ultrasound


1. size
Normal: Right lobe within normal range at midclavicular line.
Enlarged: (Hepatomegaly) right lobe >15.5 cm at midclavicular line.
Reduced: seen in chronic liver disease.
2. Liver Echotexture
Homogeneous: normal, uniform parenchymal appearance.
Heterogeneous: irregular or mixed echogenicity, may suggest fibrosis, inflammation, or cirrhosis.
Coarse: indicative of chronic liver disease (e.g., cirrhosis).
Fine: normal parenchymal texture.

3. Liver Echogenicity
Normal echogenicity The hepatic parenchyma appears slightly more echogenic (brighter) than:

• the renal cortex (of the right kidney)
• and usually also slightly brighter or equal to the spleen.
Increased echogenicity Suggests fatty infiltration (hepatic steatosis).
Markedly increased indicates severe steatosis, obscures portal veins.
Decreased echogenicity may indicate acute hepatitis or infiltrative disease.
4. Liver Contour
Smooth:normal.
Irregular: may suggest fibrosis or early cirrhosis.
Nodular: typically seen in established cirrhosis
Bulky lobes: enlarged caudate or left lobe in cirrhosis.

5. Focal Liver Lesions
By Echogenicity:
Hyperechoic: Bright compared to liver (e.g., hemangioma, lipoma).
Hypoechoic: Darker than liver (e.g., metastasis, abscess).
Isoechoic: Similar to surrounding liver (may be subtle).
Anechoic: Completely black (e.g., simple cyst).
By Appearance:
Well-defined / Poorly defined.
Homogeneous / Heterogeneous
Solid / Cystic / Complex
Target / Halo sign suggests metastasis
Calcified lesion echogenic with posterior shadowing
Vascularity (with Doppler):
Hypervascular / Hypovascular / Avascular
Internal flow / Peripheral flow

6. Biliary Tree
Normal caliber ducts no dilation
Intrahepatic ductal dilatation parallel channel sign
CBD:
Normal (<6 mm pre-cholecystectomy, <10 mm post-cholecystectomy)
Dilated
Presence of intraductal stone / mass / sludge
Patency: Patent / Thrombosed / Absent
Flow direction: Hepatopetal (normal) / Hepatofugal (abnormal)
Flow pattern: Monophasic / Triphasic
Flow pattern: Monophasic / Triphasic
7. Portal Vein and Hepatic Vasculature
Patency: Patent / Thrombosed / Absent
Flow direction: Hepatopetal (normal) / Hepatofugal (abnormal)
Flow pattern: Monophasic / Triphasic
Velocity: Normal / Increased / Decreased

8. Associated Findings
Ascites: Anechoic fluid in perihepatic, perisplenic, or pelvic regions
Splenomegaly: May accompany portal hypertension
Lymphadenopathy: Enlarged nodes near porta hepatis
Pericholecystic fluid / Gallbladder wall thickening

9. Doppler Terms
Monophasic flow: Often abnormal in hepatic veins
Triphasic flow: Normal hepatic vein waveform
Continuous flow: Seen in portal hypertension
Tardus-parvus waveform: Suggests arterial stenosis

Tardus = Latin for “slow” – indicates a delayed systolic upstroke

Parvus = Latin for “small” – indicates a reduced systolic peak velocity

This waveform pattern is commonly seen distal to a significant arterial stenosis and is an important Doppler ultrasound finding in vascular assessments.

Liver Ultrasound: Measurements and Interpretation
1. Liver Size
2. Common Bile Duct (CBD)
3. Portal Vein
4. Hepatic Veins and Artery
5. Spleen Size (For portal hypertension evaluation)
6. Ascites
7. Liver Lesions (Measurement & Description)
8. Liver Surface Nodularity
9. Parenchymal Texture

Normal Liver Size Chart by Age/Gender

Normal Liver Size Chart by Age/Gender

Mid clavicular Liver Size Chart by Age

Fetal Liver Size by Gestational Age (Weeks)

• Certainly, fetal liver length (FLL) increases with gestational age, and understanding its standard deviation (SD) is crucial for assessing normal growth patterns. Based on the study by Tongprasert et al., the relationship between FLL and gestational age (GA) from 14 to 40 weeks can be modeled using the following equations:
• Mean FLL (mm): Mean = 1.61 × GA − 6.75
• Standard Deviation (SD): SD = 0.15 × GA − 1.5

Nots: The 5th and 95th percentiles are calculated as Mean ± 1.28 × SD, assuming a normal distribution.

Fetal Liver Length by Gestational Age (Weeks)

Gestational Age (weeks)	Mean FLL (mm)	SD (mm)	5th Percentile (mm)	95th Percentile (mm)
14	15.79	0.60	14.61	16.97
16	18.99	0.90	17.52	20.46
18	22.21	1.20	20.23	24.19
20	25.41	1.50	22.91	27.91
22	28.63	1.80	25.65	31.61
24	31.83	2.10	28.38	35.28
26	35.05	2.40	31.11	38.99
28	38.25	2.70	33.84	42.66
30	41.47	3.00	36.57	46.37
32	44.67	3.30	39.30	50.04
34	47.89	3.60	42.03	53.75
36	51.09	3.90	44.76	57.42
38	54.31	4.20	47.49	61.13
40	57.51	4.50	50.22	64.80

Neoneatal Midclavicular Liver Length by Age (Months)

Age (Months)	Mean Liver Length (cm)	Standard Deviation (cm)
0 (Newborn)	5.9	±0.8
1	7.6	±1.18
2	7.8	±1.20
3	8.0	±1.22
4	8.2	±1.24
5	8.4	±1.26
6	8.6	±1.28
7	8.8	±1.30
8	9.0	±1.32
9	9.2	±1.34
10	9.4	±1.36
11	9.6	±1.38
12	9.8	±1.40

Nots: These values represent average measurements; individual variations can occur. Liver size correlates strongly with body height and weight, so these factors should also be considered during assessment.

Normal Midclavicular Liver Length by Age (1–80 Years)

Age Range (Years)	Mean Liver Length (cm)	Standard Deviation (cm)	Normal Range (cm)
1–2.5	8.5	±1.0	6.5–10.5
3–5	8.6	±1.2	6.5–11.5
5–7	10.0	±1.4	7.0–12.5
7–9	10.5	±1.1	7.5–13.0
9–11	10.5	±1.2	7.5–13.5
11–13	11.5	±1.4	8.5–14.0
13–15	11.8	±1.5	8.5–14.0
15–17	12.1	±1.2	9.5–14.5
18–25	13.6	±1.7	11.9–15.3
26–35	13.7	±1.7	12.0–15.4
36–45	14.0	±1.7	12.3–15.7
46–55	14.2	±1.7	12.5–15.9
56–65	14.4	±1.7	12.7–16.1
>66	14.1	±1.7	12.4–15.8

Normal Liver Size Chart by Age/Gender

Caudate lobe AP Diameter

The caudate lobe of the liver, located posteriorly between the inferior vena cava and the ligamentum venosum, can be evaluated using ultrasound to measure its anteroposterior (AP) diameter. While specific normative data for the caudate lobe's AP diameter across different age groups is limited, general reference values have been established in adult populations.

General Reference Values:
Adults: In healthy adults, the caudate lobe's AP diameter typically measures approximately 1.5 to 3.5 cm. Variations can occur based on individual anatomy and physiological factors.

Pediatric Considerations: While comprehensive age-specific charts are scarce, studies have established normative ranges for liver dimensions in pediatric populations, emphasizing the influence of age, body size, and ethnicity on organ size.

Clinical Significance: An increase in the size of the caudate lobe, particularly relative to the right lobe, can be indicative of certain liver pathologies. The caudate-to-right lobe (C/RL) ratio is a metric used in this context:

• A C/RL ratio < 0.6 is considered normal.
• A C/RL ratio > 0.65 suggests a high likelihood of cirrhosis.

Normal Caudate Lobe AP Diameter by Age

Age Group	Normal Caudate Lobe AP Diameter
Newborns and Infants (0–2 years)	15–20 mm
Children (3–10 years)	15–30 mm
Adolescents (13–18+ years)	20–40 mm
Adults (18+ years)	Up to 30 mm

These measurements are approximate and can vary based on individual anatomy and body size. It's important to interpret these values in the context of the patient's overall clinical picture and in comparison with other liver measurements. For instance, an increased caudate lobe size relative to the right lobe may suggest certain liver pathologies, such as-

1. Cirrhosis
2. Budd-Chiari Syndrome
3. Focal Lesions

Normal Liver Size Chart by Age/Gender

Left lobe AP Diameter

The AP diameter of the left lobe of the liver is measured from the anterior to posterior margin in the midline or left of midline. It's often evaluated to:

• Detect hepatomegaly
• Monitor chronic liver diseases
• Assess congenital or structural abnormalities

The left lobe is more variable in size than the right lobe and can extend across the midline toward the spleen. In chronic liver disease, the left lobe may hypertrophy as the right lobe atrophies.

Normal Left Lobe AP Diameter by Age

Age Group	Normal Left Lobe AP Diameter
Newborns (0–1 month)	20–30 mm
Infants (1 month–2 years)	25–40 mm
Young Children (3–5 years)	30–50 mm
Children (6–10 years)	35–60 mm
Adolescents (11–17 years)	40–70 mm
Adults (18+ years)	Up to 70 mm (7 cm)

These values are approximate. Use body surface area (BSA) or height-based nomograms for more precise pediatric assessments.

Normal Liver Size Chart by Age/Gender

Liver volume

The The three measurements were then used to determine liver volume according to Childs et al.’s equation
Liver volume (cm3) =343.71 + (0.84 × ABC) where ABC is the product of the three linear measurements.

Fetal Liver Volume by Gestational Age

Gestational Age (Weeks)	Mean Liver Volume (mL)
20	8
24	18
28	36
32	62
36	94
40	120

Liver Volume by Age Group

Liver Volume by Age Group (Approximate Values)

Age Group	Liver Volume (mL)	Notes
Newborn	120–250 mL (mean ~185 mL)	Volume varies by birth weight and length
1 year	~700–800 mL (mean ~750 mL)	Rapid growth; ~half of adult liver volume
5 years	~850–1050 mL (mean ~950 mL)	Liver volume increases with body size
10 years	~1000–1200 mL (mean ~1100 mL)	Close to adult female liver volume
Adolescents (11–17)	~1300–1800 mL (mean ~1550 mL)	Growth continues; depends on height and weight
Adult Female (18–65)	~1200–1400 mL (mean ~1300 mL)	Relatively stable
Adult Male (18–65)	~1400–1800 mL (mean ~1600 mL)	Typically larger due to body mass
Older Adults (65+)	~1200–1500 mL (mean ~1400 mL)	Slight decline (~100–200 mL) due to age-related liver shrinkage

Liver size compared to the right kidney

Normal size of the right lobe compared to the right kidney.

Enlarged right liver lobe with subtle increase in echogenicity compared to the cortex of the right kidney.

The right liver lobe is smaller and has rounded margins and an irregular outline, in keeping with fibrotic retraction

Normal Liver Size Chart by Age/Gender

Caudate-to-Right Lobe (C/RL) Ratio

C/RL Ratio Formula

\( \text{C/RL Ratio} = \frac{\text{Caudate Lobe Width}}{\text{Right Lobe Width}} \)

The Caudate-to-Right Lobe (C/RL) Ratio is a radiological measurement used to assess liver morphology, especially helpful in diagnosing cirrhosis.

• Caudate Lobe Width:Measured from the medial edge of the caudate lobe to the right border of the inferior vena cava.
• Right Lobe Width:Measured from the right lateral margin of the liver to the right edge of the middle hepatic vein (or portal vein bifurcation, depending on method).

Interpretation:

• C/RL < 0.6 → Normal
• C/RL ratio > 0.65 → Suggestive of cirrhosis
• Some sources use > 0.7 as a more specific cutoff

⚠️ These measurements are best made using cross-sectional imaging like CT or MRI. Ultrasound can be used but is more operator-dependent.