Contrast-Enhanced CT of the Abdomen Interpretation

Initial Assessment

The American Gastroenterological Association recommends confirming adequate bowel preparation and insufflation, as inadequate preparation can lead to misinterpretation, with technical parameters including slice thickness ideally 3mm for optimal spatial resolution and contrast administration protocol 1

The American College of Radiology suggests using both primary 2D and 3D visualization techniques for optimal detection of pathology, with 2D review examining enlarged images sequentially from rectum to cecum, and 3D review evaluating the endoluminal surface of organs for better visualization of lesions 1
The American College of Radiology recommends comparing supine and prone datasets when available to differentiate fixed lesions from mobile contents 1

The American College of Radiology advises assessing the liver for focal lesions, noting enhancement patterns during arterial, portal venous, and delayed phases, with multiphase contrast-enhanced CT having 91-95% accuracy for hemangiomas and 85-93% accuracy for focal nodular hyperplasia 2
The American College of Radiology suggests evaluating the appendix for signs of appendicitis, with a normal appendix having a diameter <6mm, no wall thickening, and no surrounding inflammation, and optimal cutoff for maximum outer diameter being 8.2mm (sensitivity 88.8%, specificity 93.4%) 3, 4
The American College of Radiology recommends assessing the pancreas, spleen, kidneys, and adrenals for size, contour abnormalities, and enhancement patterns 2

The American College of Radiology advises evaluating the bowel for wall thickness, enhancement pattern, and surrounding fat, with signs of bowel injury including wall thickening, abnormal enhancement, free fluid, and pneumoperitoneum 4, 5

The American College of Radiology suggests evaluating the aorta, major branches, and portal venous system for aneurysms, dissection, thrombosis, or stenosis 2

The American College of Radiology recommends that for suspected appendicitis, CECT without enteral contrast has sensitivity 90-100% and specificity 94.8-100%, comparable to CECT with enteral contrast 4, 6
The American College of Radiology advises that for indeterminate liver lesions, MRI may be necessary for definitive characterization 2
The American College of Emergency Physicians suggests that in trauma patients, CT has a sensitivity of 97% and specificity of 95% for detecting significant intra-abdominal injuries 5

Pancreatic necrosis is visible after 72 hours from onset of symptoms, and peripancreatic fluid collections and inflammation are associated with pancreatitis, as reported by the World Journal of Emergency Surgery 7
The CT Severity Index (CTSI) for pancreatitis grading is based on pancreatic inflammation/enlargement, peripancreatic fluid collections, and extent of necrosis, with >50% necrosis associated with intra-abdominal hypertension, according to the World Journal of Emergency Surgery 7

A wall thickness of >4mm is considered abnormal, and enhancement patterns (mucosal, submucosal, serosal) and surrounding fat stranding and inflammation are indicative of bowel pathology, as stated by the Journal of the American College of Radiology 8
Mural thickening and enhancement patterns, as well as fistulous tracts and strictures, are small bowel specific signs that can be visualized using CECT, according to the Journal of the American College of Radiology 8

Active extravasation of contrast in cases of GI bleeding can be detected using CECT, as reported by Radiology 9

The presence, location, and density of fluid collections, as well as abscess formation (hypodense center with rim enhancement), can be evaluated using CECT, according to the World Journal of Emergency Surgery 7

Inadequate bowel distension may obscure or mimic mucosal abnormalities, and hyperintense bowel contents may obscure subtle masses or vascular abnormalities, as noted by Radiology 9
Post-contrast acute kidney injury concerns are limited, as shown by recent meta-analyses, according to the World Journal of Emergency Surgery 7