Ultrasound has a unique role in the evaluation of internal organs. Its ability to distinguish cystic structures from solid masses has made ultrasound a critical tool for assessing pathological changes in the abdomen before operative intervention. Ultrasonography is a safe, portable, and non-invasive technique with no harmful side effects.
A cyst on ultrasound examination characteristically appears as an anechoic, thin-walled structure. A complicated cyst has a thick wall and may contain internal echoes.
Posterior shadowing is associated with a stone.
It is important to remember that solid masses may appear on ultrasonography as shades of gray. While hepatomas may appear heterogeneous, metastatic tumors may appear hypoechoic or hyperechoic.
Indications for Abdominal Ultrasound
Acute Abdomen
Due to its ease of use, low risk, and relatively low cost, ultrasound has become a safe and accessible alternative to CT, MRI, and other minimally invasive approaches in the evaluation of patients with abdominal pain.
Abdominal ultrasound findings often complement physical examination and can guide further diagnostic studies or operative interventions. Hernias, acute cholecystitis, appendicitis, bowel obstruction, bowel ischemia, and diverticulitis are among the many conditions presenting with acute abdominal pain that can be structurally evaluated with ultrasonography.
In cases of acute abdomen, ultrasonography is performed while the patient is lying supine. The technique is not different from standard ultrasonography. The examination begins with the evaluation of the liver and gallbladder, followed by the common bile duct. The retroperitoneum, right and left kidneys, pancreas, and upper abdominal organs are systematically imaged.
The evaluation is completed by imaging the pelvis and searching for the presence of intra-abdominal fluid. Subsequent steps focus on examining the reported area of pain.
An inflamed appendix is easier to visualize than a normal appendix due to its increased size and fluid-filled distension. It appears as a tubular structure with a laminated wall and blind end emerging from the cecum base; it is especially non-compressible and aperistaltic with a diameter greater than 6 mm.
Small Bowel Obstruction
Ultrasonography is useful in supporting the diagnosis of ileus or bowel obstruction along with direct radiographic films. The examination for possible bowel obstruction starts with systematic longitudinal and transverse scans of the abdominal cavity.
The lumen measures between 3 and 5 mm and can be easily compressed during gradual compression. The sonographic sign for diagnostic purposes is the “target” appearance of the bowel in the transverse view and a transverse diameter of 10 to 20 mm for the small intestine and 30 mm for the colon.
An obstructed bowel appears swollen, filled with fluid, and lacks peristalsis. Computed tomography is superior to ultrasonography in determining the cause and location of bowel obstruction. However, ultrasonography is considered the preferred method for diagnosing intussusception.
Hernias and Abdominal Wall Masses
Abdominal ultrasound can be used to identify and distinguish hernias, seromas, abscesses, and other abdominal wall masses. Additionally, it can guide aspiration or biopsy of such lesions with high accuracy and minimal morbidity or risk to the patient.
Abdominal Aortic Aneurysm
Abdominal aortic aneurysm should be considered in any patient presenting with unexplained abdominal pain. In unstable patients, a CT scan takes time and may delay definitive treatment. Bedside transabdominal ultrasound can quickly and accurately detect the presence and size of ruptured or non-ruptured AAA with a sensitivity approaching 100%.
Solid Organ Injury
Ultrasound has become an indispensable tool in the emergency room setting and in the care of acutely traumatized patients. Focused assessment with trauma ultrasound is a limited ultrasound evaluation solely aimed at determining the presence of free intraperitoneal or pericardial fluid. It is fast, can be performed bedside, and offers the option of serial scanning, which can aid in monitoring a trauma patient being treated non-surgically.
Gallbladder and Bile Duct Pathology
Abdominal ultrasound is the preferred initial diagnostic method in cases of suspected cholecystitis and choledocholithiasis, as the detection of gallstones and bile duct stones will aid in further treatment.
The normal gallbladder typically appears as an anechoic, oval-shaped, thin-walled structure located just under the right lobe of the liver, lateral to the portal vein. It is sometimes encased within the liver parenchyma or located lower towards the right iliac fossa. It can be best evaluated during fasting.
Gallstones appear as round, mobile echogenic foci within the lumen of the gallbladder. Stones larger than 1 mm usually produce an acoustic shadow. Typical findings of acute cholecystitis include gallbladder wall thickening of more than 4 mm, hypoechoic thickening of tissues surrounding the gallbladder, pericholecystic fluid, and localized pain when the gallbladder is imaged with slight compression, known as the “sonographic Murphy’s sign.”
Ultrasound can also be used to detect other pathological findings in the gallbladder and biliary tree, including adenomyomatosis, polyps, malignant neoplasms, and bile duct obstruction due to choledocholithiasis.
Ultrasonography has a sensitivity of 75% in detecting stones within the common bile duct. The normal extrahepatic bile duct should be less than 6 mm at the level where the right hepatic artery passes. In the presence of obstructive symptoms, a dilated duct is highly suggestive of choledocholithiasis, confirmed by the presence of echogenic stones with distal acoustic shadowing on ultrasonography.
Liver Pathology
The normal liver is a homogeneous structure that is more echogenic than the renal cortex but less echogenic than the spleen. Anatomically, it is divided into eight segments according to the branching of the portal structures and hepatic veins, which appear as sonolucent tubular structures within the liver parenchyma.
The liver is best evaluated with the patient slightly turned to the left, which allows the liver to shift downward for better visualization. The patient should hold their breath to press against the diaphragm.
Abdominal ultrasound is often used to detect and localize benign or malignant neoplasms, metastases, cysts, hemangiomas, and abscesses in the liver. Hepatic adenomas typically appear as well-circumscribed, isolated lesions with variable echogenicity on ultrasound.
It is difficult to distinguish focal nodular hyperplasia from an adenoma. Liver metastases have variable appearances depending on their origin, and no characteristics routinely separate them from primary hepatocellular carcinoma.
Tumors originating from the gastrointestinal system are more commonly multifocal, hyperechoic, and have a hypoechoic rim creating a “target” appearance on ultrasound. Hepatocellular carcinoma is more commonly hypoechoic compared to the surrounding liver parenchyma, with posterior echo enhancement or a “halo” effect.
The spleen generally has a craniocaudal dimension of 12 cm and a triangular shape. Spleen size can increase in conditions such as portal hypertension, lymphoma, or infection. Enlargement gives the spleen a rounded, full appearance.
Cysts and hemangiomas may develop in the spleen. The most common malignant splenic abnormality is lymphoma.
Imaging the pancreas can be difficult due to the air content in the stomach or bowel gas in the transverse colon.
When confirmation or exclusion of pancreatitis is requested, the source of symptoms and the ability of ultrasound to show abnormalities should be considered. Despite abnormal blood biochemistry, there may be no findings on ultrasound in the early days.
If a pancreatic mass or unexplained dilation of the pancreatic duct is suspected, further analysis with CT or MRI examination is indicated.
Signs during ultrasound that are highly suggestive of pancreatic head carcinoma include:
A mass in the hepatic hilum/pancreatic head region.
Dilation of both the bile duct and pancreatic duct (“double duct sign”).
Clinically painless jaundice.
Kidneys
Routine images consist of long-axis and transverse views. The normal kidney length is approximately 11 to 12 cm. The normal width is approximately 4 to 5 cm. The renal cortex should be evaluated for contour and thickness in terms of echogenicity.
The normal renal cortex appears iso- or hypoechoic compared to the liver and spleen. Occasionally, a hump-like protrusion may be seen in the mid-portion of the left kidney. This is due to pressure from the spleen on the left kidney and displays normal parenchymal characteristics.
The kidneys should be evaluated for atrophy, scar tissue, calcification, hydronephrosis, and masses.
The renal medulla contains pyramids, which are hypoechoic compared to the cortex. The renal sinus is more centrally located and appears echogenic secondary to fatty tissue. The renal sinus contains the main branches of the renal artery and vein, the collecting system, and lymphatics.
When hydronephrosis is present, the affected collecting system should always be compared to the opposite side. This provides information on whether hydronephrosis is unilateral or bilateral, as well as the level and localization of the obstruction. In cases where hydronephrosis is present, previous studies can be compared to assess kidney size.
The ability of ultrasound to detect kidney stones depends on: primarily, the size and location of the stone as primary factors, while the composition of the kidney stone, hydration status, hydronephrosis, and the presence of kidney and vascular diseases are secondary factors.
One of the most common abnormalities in the kidneys is cysts. Cysts are usually asymptomatic. Uncomplicated cysts have thin walls, anechoic content, and increased sound transmission.
The size of cysts can vary significantly. It is important to carefully evaluate the cyst wall and rule out the solid component. If solid components or septations are present, further characterization with abdominal CT is indicated.
One of the most common malignant lesions in the kidney is renal cell carcinoma (RCC). It is usually a solid mass with a heterogeneous echo pattern and vascularization.
Bladder
The bladder must be full for adequate evaluation of the bladder wall. The bladder typically has a smooth wall and anechoic content.
In the event of trauma, blood clots appear as mobile echogenic content in the bladder.
Wall irregularities may indicate a bladder tumor. It is helpful to have the patient turn to the left/right side during examination to assess the mobility of the abnormality. The tumor will not move, while sludge/stones and clots will move.
Full Abdominal Ultrasound Prices 2026
In Istanbul, the prices for a full abdominal ultrasound test vary from region to region and even from institution to institution in the same region. For information on full abdominal ultrasound prices, you can call 02126321059.