Abdominal Ultrasound and Hepatic Elastography

What Is Abdominal Ultrasound

Abdominal ultrasound is a non-invasive imaging technique that uses high-frequency sound waves to produce real-time images of the organs within the abdomen. A handheld transducer is placed on the skin of the abdomen, emitting sound waves that bounce off internal structures and return to the transducer, where they are converted into detailed images displayed on a monitor. Abdominal ultrasound is painless, involves no radiation, and is one of the most commonly performed diagnostic imaging studies in medicine. It is the first-line investigation for evaluating the liver, gallbladder, bile ducts, pancreas, spleen, kidneys, and major abdominal blood vessels.

What Is Hepatic Elastography

Hepatic elastography is an advanced ultrasound-based technique that measures the stiffness of the liver tissue. Liver stiffness is directly correlated with the degree of fibrosis (scarring) — the stiffer the liver, the more fibrotic it is. Elastography provides a quantitative, non-invasive assessment of liver fibrosis, often replacing the need for liver biopsy in many clinical scenarios.

How It Works

Elastography measures the speed at which shear waves propagate through the liver parenchyma. In healthy, soft liver tissue, waves travel slowly; in fibrotic, stiff tissue, waves travel faster. The result is expressed in kilopascals (kPa) or meters per second (m/s) and is compared to established cutoff values for different stages of fibrosis (F0 to F4, where F4 represents cirrhosis).

Comparison with FibroScan

FibroScan (transient elastography) is a dedicated device specifically designed for liver stiffness measurement. Point shear wave elastography (pSWE) and two-dimensional shear wave elastography (2D-SWE), available on modern ultrasound machines, offer comparable accuracy with the added advantage of simultaneous anatomical imaging — meaning the physician can visualize the liver in real time and ensure the measurement is taken from a suitable location, avoiding vessels, masses, or areas of focal disease. Both methods are validated in international guidelines for the non-invasive assessment of liver fibrosis.

Indications

Abdominal Ultrasound

• Abdominal pain — evaluation of organs for inflammation, stones, masses, or fluid collections
• Gallbladder disease — detection of gallstones, cholecystitis, gallbladder polyps
• Liver evaluation — assessment of liver size, texture, focal lesions (cysts, hemangiomas, tumors), and fatty liver disease
• Bile duct dilation — investigation of obstructive jaundice and bile duct stones
• Pancreatic evaluation — detection of masses, cysts, or signs of pancreatitis
• Kidney assessment — stones, hydronephrosis, cysts, tumors
• Spleen evaluation — size assessment in portal hypertension, splenic lesions
• Ascites — detection and quantification of free fluid in the abdomen
• Abdominal aorta — screening for aneurysm in at-risk populations
• Follow-up imaging — monitoring known conditions over time

Hepatic Elastography

• Chronic hepatitis B or C — assessment and staging of liver fibrosis to guide treatment decisions
• Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) — determining whether fibrosis has developed
• Alcoholic liver disease — evaluating the degree of liver damage
• Monitoring treatment response — tracking changes in fibrosis after antiviral therapy for hepatitis or lifestyle modifications
• Screening for advanced fibrosis or cirrhosis in at-risk populations
• Avoiding liver biopsy — elastography often provides sufficient fibrosis staging information, sparing the patient an invasive procedure

Patient Preparation

• Fasting: Do not eat or drink for 6 to 8 hours before the examination. Fasting ensures the gallbladder is fully distended (making it easier to evaluate) and reduces intestinal gas that can obscure visualization of deeper structures.
• Avoid carbonated drinks: For at least 12 hours before the exam, avoid carbonated beverages and gas-producing foods (beans, cabbage, broccoli), as bowel gas interferes significantly with ultrasound imaging.
• Medications: Continue all regular medications as prescribed. Take them with a small sip of water if needed.
• Clothing: Wear loose, comfortable clothing. You will need to expose your abdomen during the examination.
• For elastography specifically: Avoid eating for at least 2 hours before the measurement. Food intake can transiently increase portal blood flow and liver stiffness, potentially leading to falsely elevated readings. Avoid vigorous exercise and alcohol consumption for 24 hours before the test for the same reason.

What the Exam Feels Like

Abdominal ultrasound is completely painless and requires no sedation. You will lie on your back (or turn to different positions as instructed) on an examination table. The examiner applies a clear, water-based gel to your skin — this gel helps transmit the ultrasound waves and may feel slightly cool. The transducer is then pressed gently against your abdomen and moved across different areas. You may be asked to take deep breaths and hold them briefly to move the liver and other organs into a better scanning position. The examination typically takes 15 to 30 minutes.

For elastography, the transducer is held steadily in one position over the right lobe of the liver (usually between the ribs). You will be asked to hold your breath for a few seconds during each measurement. Several measurements are taken and averaged. The process adds only 5 to 10 minutes to the standard ultrasound examination. There is no pain or discomfort associated with elastography.

What Conditions Can Be Detected

• Gallstones and cholecystitis — ultrasound is the gold standard for detecting gallstones, with sensitivity exceeding 95%.
• Fatty liver disease (hepatic steatosis) — characteristic increased echogenicity of the liver parenchyma indicates fat accumulation.
• Liver cirrhosis — ultrasound reveals a nodular liver surface, altered echotexture, and signs of portal hypertension (splenomegaly, ascites, collateral vessels). Elastography quantifies the degree of fibrosis.
• Liver tumors — focal lesions such as hepatocellular carcinoma, metastases, hemangiomas, and focal nodular hyperplasia can be identified and characterized using Doppler imaging and contrast-enhanced ultrasound.
• Bile duct dilation — a dilated common bile duct suggests obstruction, prompting further investigation with MRCP or ERCP.
• Pancreatic abnormalities — masses, cysts, calcifications (chronic pancreatitis), and ductal dilation.
• Kidney stones and hydronephrosis — stones and urinary tract obstruction are readily identified.
• Splenomegaly — enlargement of the spleen, often associated with portal hypertension or hematological conditions.
• Ascites — even small amounts of free fluid can be detected.
• Abdominal aortic aneurysm — dilation of the aorta that may require monitoring or surgical repair.

Results Interpretation

Ultrasound Report

The examining physician will provide a written report describing the size, shape, echogenicity, and any abnormalities of each organ examined. Key findings will be highlighted, and recommendations for further investigations (CT, MRI, biopsy) will be included if needed. The report is typically available the same day or the next business day.

Elastography Results

Liver stiffness values are interpreted using established reference ranges (values may vary slightly depending on the technique and manufacturer):

• < 7 kPa: Normal or minimal fibrosis (F0-F1) — no significant liver scarring.
• 7-9.5 kPa: Moderate fibrosis (F2) — some scarring is present. Lifestyle modifications and medical management are typically recommended.
• 9.5-12.5 kPa: Severe fibrosis (F3) — significant scarring. Close monitoring and active treatment are important.
• > 12.5 kPa: Cirrhosis (F4) — advanced scarring with architectural distortion. Comprehensive management including screening for complications (varices, hepatocellular carcinoma) is required.

It is important to note that liver stiffness can be falsely elevated in the setting of acute hepatitis, liver congestion (heart failure), cholestasis, or recent food intake. Your doctor will interpret the results in the context of your clinical picture and laboratory findings.

Practical Tips

• Schedule your appointment in the morning — it is easier to fast overnight, and morning examinations tend to produce the best image quality.
• Bring previous ultrasound reports and imaging studies if available. Comparison with prior results allows the physician to track changes over time.
• Do not chew gum before the exam — it stimulates swallowing of air, which increases bowel gas and degrades image quality.
• If you have diabetes and are concerned about fasting, speak with your doctor about adjusting your insulin or oral medication dosing for the day of the exam.
• The examination is completely safe and can be repeated as often as clinically needed — there is no cumulative radiation exposure, unlike CT scans.
• For elastography monitoring (e.g., tracking fibrosis after hepatitis treatment), aim to have measurements performed at the same facility on the same equipment for the most reliable comparison over time.