Reading a CT abdomen is a systematic process that begins at the skin surface and moves inward toward the spine, evaluating each organ system for normal anatomy and pathologic findings. Mastery of this skill requires knowledge of sectional anatomy, windowing techniques, and the typical variations that can mimic disease. This guide outlines the essential steps for a competent and confident interpretation of abdominal CT scans.
Initial Survey and Technical Assessment
Before interpreting anatomy, verify that the study is complete and technically adequate. Check the patient name, study date, and scan parameters to ensure you are reviewing the correct examination. Assess image quality for artifacts, motion, and contrast enhancement, as these factors directly impact the visibility of subtle findings. A quick overview of the entire series helps identify missing phases, such as portal venous or delayed imaging, which may be critical for specific diagnoses.
Evaluating the Body Wall and Peritoneum
Begin at the periphery of the image and assess the body wall, including skin, subcutaneous fat, and abdominal muscles for swelling, hematoma, or masses. Move centrally to evaluate the peritoneal fat planes; clear, sharp fat planes indicate normal anatomy, while haziness or obliteration suggests inflammation, such as peritonitis or diverticulitis. Identify the liver, spleen, kidneys, and adrenal glands, noting their size, contour, and homogeneous parenchymal texture without focal lesions.
Analyzing the Gastrointestinal Tract
The stomach and intestines should be evaluated for wall thickness, enhancement, and lumen diameter. Thickened wall with contrast enhancement may indicate infection, ischemia, or malignancy, while dilated loops of bowel suggest obstruction. Pay attention to the mesentery for stranding or fluid, which can indicate inflammation or infection, and inspect the liver for cysts, hemangiomas, or metastatic disease using appropriate window settings.
Assessing the Solid Organs and Vasculature
Examine the liver, spleen, pancreas, and adrenals for focal lesions, diffuse enlargement, or abnormal attenuation. The pancreas should demonstrate uniform enhancement without local hypodensity, and the main pancreatic duct should not be prominently dilated. Evaluate the vasculature, including the aorta and its major branches, for aneurysm, dissection, or occlusion, ensuring that the contrast phase is optimal for vascular pathology.
Recognizing Normal Variants and Pitfalls
Familiarize yourself with common variants that can be mistaken for pathology, such as a prominent gastric fundus, redundant sigmoid colon, or accessory spleen. Iatrogenic changes from prior surgery or stent placement should be identified to avoid misinterpretation. Understanding these patterns reduces unnecessary follow-up and ensures that true abnormalities are not overlooked.
Communicating Findings Clearly
Report findings in a structured format, starting with the technical quality of the study, followed by positive and negative findings. Use precise language to describe location, size, and characteristics of lesions, and correlate imaging with clinical history when available. Clear communication ensures that clinicians can make informed decisions based on accurate and actionable radiology reports.
