The liver is the first organ most sonographers learn to scan — and one of the most information-rich. A thorough hepatic evaluation includes size, echogenicity, surface, vascular patency, and a systematic review for focal lesions. Getting each element right is what separates a complete study from one that misses significant pathology.

This guide covers liver ultrasound normal size measurements, echogenicity grading, hepatomegaly criteria, and the key findings you need to recognize and document.

Normal Liver Size

Liver size varies significantly with body habitus, and "normal" encompasses a wide range. The most commonly used measurement is the midclavicular line (MCL) longitudinal span.

Liver Span (MCL)

Population	Normal Range
Adult	≤ 15–16 cm (MCL)
General guideline	≤ 15 cm (most departments)

Important limitation: MCL span alone is an imperfect measurement. A large patient may have a liver > 15 cm that is normal for their body habitus. A small patient may have a borderline liver at 14 cm. Always correlate with clinical context.

Alternative Size Descriptors

When liver span is difficult to obtain (patient habitus, poor visualization), some departments use qualitative size descriptions:

Normal size — liver edge not extending significantly below the right costal margin
Mildly enlarged — mild extension below costal margin, < 2–3 cm
Moderately enlarged — 3–5 cm below costal margin
Markedly enlarged — > 5 cm below costal margin, reaching toward the iliac fossa

Normal Liver Echogenicity

The liver is the reference standard for abdominal echogenicity. In a normal patient:

The liver is isoechoic or mildly hyperechoic compared to the right kidney cortex
The liver is isoechoic or mildly hypoechoic compared to the spleen
The parenchyma is uniformly homogeneous throughout

Echogenicity Grading Scale

Grade	Description	Finding
Grade 0	Normal	Liver = right kidney echogenicity
Grade 1 (mild steatosis)	Liver slightly hyperechoic to kidney, vessels still visible	Near echo
Grade 2 (moderate steatosis)	Liver moderately hyperechoic, diaphragm still visible	Moderate echo
Grade 3 (severe steatosis)	Liver markedly hyperechoic, diaphragm not visible, poor deep penetration	Far echo

The right kidney is your reference. If you cannot compare directly, the spleen is an alternative. Increased liver-to-kidney echogenicity difference indicates steatosis or medical renal disease.

Hepatic Steatosis (Fatty Liver)

Fatty liver is the most common incidental hepatic finding in sonography — and one of the most important to accurately grade.

Sonographic Features

Grade	Sonographic Appearance
Mild (< 33% fat)	Mildly increased echogenicity, hepatic vessels clearly visible
Moderate (33–66% fat)	Moderately increased echogenicity, portal vein walls less distinct, slight deep attenuation
Severe (> 66% fat)	Markedly increased echogenicity, portal vein walls not visible, diaphragm not visible, significant posterior attenuation

Reporting language: Use "echogenic liver consistent with hepatic steatosis, Grade 1/2/3" or "increased hepatic echogenicity — steatosis cannot be excluded." Avoid "fatty liver" without grading when possible.

Conditions That Mimic Steatosis

Cirrhosis — heterogeneous echogenicity, not diffuse smooth increase
Amyloid — diffuse hyperechogenicity, clinical context helps
Acute hepatitis — may cause hypoechogenicity (periportal edema)

Surface and Contour Assessment

Normal liver surface is smooth on the capsule (seen between the liver and ascites, or against the diaphragm). Abnormal surface findings are important indicators of underlying disease.

Surface Finding	Association
Smooth	Normal
Nodular (fine)	Cirrhosis (most specific finding)
Coarse / irregular	Advanced fibrosis
"Bumpy" capsule	Regenerative nodules in cirrhosis

Nodular surface + ascites + splenomegaly = classic triad of cirrhosis on ultrasound.

Portal Hypertension Findings

When cirrhosis or portal hypertension is suspected, document:

Finding	Normal	Portal Hypertension
Portal vein diameter	≤ 13 mm	> 13 mm (dilated)
Portal vein flow	Hepatopetal (toward liver)	Hepatofugal (away from liver) = advanced
Flow velocity	15 – 40 cm/s	< 15 cm/s (sluggish)
Splenomegaly	≤ 12 cm	> 12 cm
Ascites	Absent	Present (perihepatic, perisplenic)
Varices	Absent	Gastric, splenic, retroperitoneal

Hepatofugal portal flow (flow away from the liver) indicates severe portal hypertension with reversal of portal flow — a critical finding requiring urgent communication.

Hepatic Vasculature

Hepatic Veins

Three hepatic veins drain into the IVC at the hepatocaval junction:

Hepatic Vein	Location
Right hepatic vein (RHV)	Between anterior and posterior right lobe segments
Middle hepatic vein (MHV)	Between right and left lobes
Left hepatic vein (LHV)	Within the left lobe

Normal hepatic vein Doppler: Triphasic waveform reflecting cardiac cycle — two antegrade peaks (S and D waves) and one retrograde peak (A wave).

Pulsatile = normal
Flat / monophasic = Budd-Chiari syndrome, cardiac disease
Loss of phasicity = hepatic fibrosis, external compression

IVC

Normal caliber ≤ 20 mm
Collapses > 50% with inspiration (sniff test)
Dilated, non-collapsing IVC = elevated right atrial pressure (heart failure)

Common Focal Liver Lesions

Lesion	Key Sonographic Features
Simple cyst	Anechoic, smooth walls, posterior acoustic enhancement, no solid component
Hemangioma	Echogenic (in normal liver), well-defined, no Doppler flow internally
FNH	Often isoechoic to liver, central scar, spoke-wheel Doppler
HCC	Variable echogenicity, arterial flow on Doppler, cirrhotic liver context
Metastases	Multiple, varied echogenicity, "target" or "bull's-eye" appearance
Abscess	Complex, heterogeneous, echogenic debris, posterior enhancement

Always describe any focal lesion by: size (three dimensions), echogenicity relative to liver, margins, posterior acoustic behavior (enhancement vs. shadow vs. none), and Doppler characteristics.

Biliary Assessment (Integrated with Liver Exam)

Structure	Normal	Abnormal
Intrahepatic ducts	Not visible (< 2 mm)	> 3 mm = dilated
CBD	≤ 6 mm (< 60 yrs)	> 6 mm = dilated (investigate)
CBD (post-cholecystectomy)	≤ 10 mm	> 10 mm = dilated

Key Images for Your Worksheet

Right lobe — longitudinal with MCL span measurement
Right lobe — transverse (at portal bifurcation)
Left lobe — longitudinal and transverse
Hepatic veins — converging at IVC (longitudinal)
Portal vein — at hilum with diameter measurement
Portal vein Doppler — confirm hepatopetal flow and velocity
Hepatic vein Doppler — triphasic waveform (at least one)
Any focal lesion — three planes, Doppler
Right kidney — for echogenicity comparison

Quick Reference Summary

Parameter	Normal Value
Liver span (MCL)	≤ 15 cm
Portal vein diameter	≤ 13 mm
Portal vein flow	Hepatopetal
Portal vein velocity	15 – 40 cm/s
CBD (< 60 yrs)	≤ 6 mm
CBD (≥ 60 yrs)	≤ 8 mm
Intrahepatic ducts	Not visible (< 2 mm)
Echogenicity	Isoechoic or mildly hyperechoic to R. kidney

Access Liver Reference Tables in SonoBuddy

SonoBuddy's abdominal measurement section includes complete liver, biliary, and portal vascular reference values — available instantly on your phone in the scan room.

Open SonoBuddy → Measurements → Liver for the full reference table.

References: AIUM Practice Parameters for Abdominal Ultrasound. Hertzberg BS, Middleton WD. Ultrasound: The Requisites, 3rd ed. ACR–AIUM–SPR Practice Parameter.

SonoBuddy is a reference tool, not a diagnostic authority. Clinical decisions must involve the ordering provider and interpreting physician.

Liver Ultrasound Normal Size and Echo Pattern: Reference Guide for Sonographers