Reading a CT scan of the abdomen requires a systematic approach to avoid missing critical pathology. This process begins with verifying patient identity and scan parameters, followed by a structured evaluation of the abdominal organs, vasculature, and surrounding structures. The goal is to identify normal anatomy, variants, and any abnormalities that may explain the patient's symptoms or clinical findings.
Preparation and Initial Survey
Before diving into organ-specific analysis, ensure the scan is suitable for interpretation. Check for artifacts caused by metallic objects, motion, or contrast timing. Assess image quality in terms of spatial resolution, noise, and uniformity. A poor-quality scan may necessitate a repeat study, as misinterpretation due to technical limitations can lead to significant clinical consequences.
Organ-Specific Analysis
Liver, Gallbladder, and Biliary Tract
The liver should appear homogeneous with smooth margins. Focal lesions, whether hypervascular or hypovascular, must be characterized in relation to the background parenchyma. The gallbladder is evaluated for wall thickening, stones, and distension. Dilatation of the biliary ducts suggests obstruction, often caused by stones or mass lesions in the head of the pancreas.
Pancreas and Peripancreatic Space
The pancreas is assessed for size, contour, and the presence of focal masses or diffuse enlargement. Pancreatitis may show gland enlargement, peripancreatic stranding, and fluid collections. Suspected masses require evaluation of vascular encasement, particularly involvement of the superior mesenteric artery and portal vein, which influences surgical resectability.
Kidneys, Adrenals, and Retroperitoneum
Renal parenchyma should have homogeneous attenuation without areas of infarction or abscess. Collecting system dilatation indicates obstruction. The adrenal glands are inspected for masses; incidentalomas are common, but specific features may suggest adenoma, pheochromocytoma, or metastasis. The retroperitoneum is scrutinized for enlarged lymph nodes, hemorrhage, or extranodal spread of tumor.
Vascular and Mesenteric Evaluation
The aorta and its major branches are measured for diameter and assessed for aneurysms, dissections, or atherosclerotic disease. Mesenteric vessels are evaluated for thrombosis or embolism, which present as bowel wall thickening, pneumatosis, or portal venous gas. Portal vein patency is crucial in patients with liver disease or suspected mesenteric ischemia.
Soft Tissues and Bone Structures
Beyond the hollow organs, the integrity of the abdominal wall and musculature is noted. Hernias, herniated hardware, and postsurgical changes are common findings. The bones are surveyed for fractures, lytic or blastic lesions, and degenerative changes. Special attention is given to the spine for alignment and evidence of metastatic disease or infection.
Report Generation and Communication
A structured report begins with an impression that answers the clinical question. Key findings are summarized in a concise manner, with critical diagnoses highlighted first. Recommendations for further imaging or clinical management should be specific. Clear communication with the referring clinician ensures that the imaging findings directly impact patient care.
