Abdominal radiology is a medical imaging prescribed to diagnose the abdominal organs diseases associated with liver, gallbladder, pancreas, spleen, gastrointestinal tract, kidneys, and abdominal blood vessels taken by using imaging techniques like X-ray, ultrasound, CT, and MRI.
Abdominal imaging is mainly prescribed for abdominal pain, trauma, infections, tumors, and chronic diseases, helping guide clinical management and treatment decisions. It is a subdiscipline of radiological methods. It deals with the imaging, analysis, and interpretation of the diseases in the abdominal and pelvic organs, such as the liver, gastrointestinal tract, pancreas, kidneys, and associated vascular and peritoneal structures. It involves the use of multiple imaging modalities such as ultrasound, CT, MRI, etc.
Abdominal organs are prone to several disease conditions. The main organs affected by such conditions are explained below:
The liver is the largest solid organ, located in the upper right corner of the abdomen. From the perspective of radiology, the liver is divided into eight regions, following the Couinaud classification. These divisions are based on portal vein and hepatic vein anatomy, which are crucial for CT and MRI examinations. Typical liver diseases consist of fatty liver disease, hepatitis, cirrhosis, abscesses, and neoplasms such as hepatocellular carcinoma and metastases. For the liver, ultrasound is the examination of choice to detect hepatomegaly, fatty infiltration, cirrhotic changes, ascites, and focal lesions. Contrast-enhanced CT is useful to determine liver morphology, whereas MRI is used to characterize liver lesions and differentiate benign from malignant tumors.
The gallbladder is situated close to the liver and acts as a repository for bile and other digestive juices. Other parts of the biliary system consist of intrahepatic bile ducts, the common hepatic duct, the cystic duct, and the common bile duct. The gallbladder and the biliary system are typically affected by gallstones, cholecystitis, biliary obstruction, and malignancies such as cholangiocarcinoma. Ultrasound is the commonly used imaging modality for the gallbladder. However, normal bile ducts are not in an ultrasound and thus need to be dilated. CT is effective in the identification of complications such as perforation, emphysematous cholecystitis, or abscess formation. Magnetic resonance cholangiopancreatography (MRCP) is another imaging modality that examines the non-invasive visualization of the biliary tree.
The pancreas spans across the upper abdomen and is divided into the head, uncinate process, body, and tail. It is located close to the superior mesenteric vessels and the portal vein, which makes it important for pancreatic tumor staging. To diagnose pancreatitis, contrast-enhanced CT is the examination of choice. This technique is also effective to assess pancreatic enlargement, necrosis, fluid collections, and complications such as abscesses or vascular involvement. Ultrasound is another useful approach; however, evaluation might be hampered due to overlying bowel gas. MRI and MRCP as useful in the detection of pancreatic ductal anatomy, cystic lesions, and chronic arepancreatitis.
The kidneys are paired retroperitoneal organs located on either side of the spine. The adrenal glands are located above the kidneys and appear in a Y or V shape under imaging. The kidney morphology, obstruction, and cystic disease are generally observed using ultrasound. Non-contrast CT is the gold standard for detecting renal stones. Contrast-CT and MRI are effective to detect renal masses, assess vascular involvement, and stage malignancies.
Abdominal radiology techniques, such as plain abdominal radiographs, CT, MR enterography, Doppler ultrasound, etc., are commonly used to detect conditions in several organs. These organs consist of the spleen, the gastrointestinal tract, and the abdominal vascular system.
Considering the anatomical and functional aspects of the abdominal complications, the most commonly used radiological imaging techniques are given below:
Ultrasound is the most preferred imaging modality in abdominal complications. It is generally the primary screening method employed after gastrointestinal complaints. It uses high-frequency sound waves, which echo back from the organs. These waves are captured and converted into images. This technique provides real-time visualization of the abdominal anatomy. Effective in observing solid organs, this method is typically preferred for gallstones, biliary dilation, ascites, renal obstruction, cystic lesions, and organomegaly. Doppler ultrasound is useful in diagnosing portal hypertension, portal vein thrombosis, renal artery stenosis, and hepatic venous outflow obstruction.
CT consists of a rotating device that exposes different sides of the body to ionizing radiation. This creates simple 2D images of a single angle. A computerized system combines these 2D images from multiple axes and creates a high-quality 3D image. Paired with contrast-enhancing, CT becomes a useful tool in diagnosing abdominal disorders. It is the preferred imaging technique for acute abdomen, trauma, abdominal infections, tumors, and staging of malignancies. It is highly sensitive for detecting appendicitis, bowel obstruction, perforation, pancreatitis, abdominal abscesses, and vascular emergencies such as aneurysms and ischemia. Non-contrast CT is the gold standard for renal stone detection.
This is one of the oldest imaging modalities, which was used in emergency settings. Like ultrasound, X-ray abdomen is also an initial screening for several complications. It involves exposure of the abdomen to a small amount of radiation to generate simple 2D images. It is an effective method to observe bowel obstruction through dilated bowel loops and air-fluid levels, intestinal perforation by identifying free intraperitoneal air under the diaphragm, and radiopaque calculi in the urinary tract. It is also used to assess bowel gas patterns and foreign bodies.
A number of diseases and abdominal conditions can be diagnosed using abdominal radiology methods. These conditions are listed below:
Listed below are the key roles and responsibilities of abdominal radiologists:
With the evolution of imaging techniques, abdominal radiology has been further subdivided into individual specialties based on the organs. These subspecialties are explained below:
Hepatobiliary radiology focuses on the imaging of the liver, gallbladder, bile ducts, and biliary tree. Since liver and biliary diseases are complex, radiologists must be skilled specifically in the anatomy, physiology, and diseases of these organs.
This category consists of imaging and analysis of the esophagus (abdominal portion), stomach, small intestine, colon, rectum, and peritoneal cavity. GI radiology is involved in the assessment of conditions such as bowel obstruction, perforation, inflammatory bowel disease, ischemia, gastrointestinal bleeding, and malignancies of the stomach and colon.
This subspecialty is dedicated to the diagnosis, stage assessment, treatment, and surveillance of abdominal cancers. Instead of a single organ, this subcategory is intended to assess cancer-related findings throughout the abdominal region.
Abdominal radiology covers a section of radiology practices. It consists of radiology techniques to analyze the abdominal anatomy.
Just like any analysis method, each abdominal radiology method has its own limitations. Typical drawbacks include non-specific imaging findings, lower image quality, etc.
Abdominal radiology deals with initial screening of abnormalities in the specific areas. Using this data, radiologists can determine the initial stages of gastrointestinal complications, leading to timely interventions.
There is a set of guidelines and safety parameters in place for abdominal radiological examinations. These include selection of the accurate imaging test, pre-examination tests, and strict analysis monitoring.
Quality in abdominal radiology is maintained by several measures in place. These include use of standardized techniques, consistent updates in imaging technology, upskilling of abdominal radiologists, etc.
This field is essential, as the findings could be directly linked to cross-organ effects, malignancies, and other complications. These complications can affect several other sections and systems of the body.
Future prospects of abdominal radiology will lead to further optimization and upgrading of existing techniques. Artificial intelligence (AI) and machine learning (ML) are also being integrated into abdominal radiology practices.
