小肠疾病影像学诊断.pptx

Case Discussion;Axial arterial phase;  Axial arterial phase;  Axial venous phase;  Coronal arterial phase;  Sagittal venous phase;Crohn disease; An inflammatory disease of the gastrointestinal tract that typically has an indolent course Characterized by intestinal ulceration, strictures, and fistula formation Commonly affects young adults, small bowel, particularly the terminal ileum Small bowel involvement in Crohn disease is typically transmural, with skip lesions CT and MRI ; CT and MRI Useful for differentiating between active and fibrotic bowel strictures Allowing visualization of the entire thickness of the bowel wall Depicting extraenteric involvement Providing more detailed and comprehensive information about the extent and severity; Comb sign Fat halo sign Bowel wall enhancement Bowel wall thickness Stricture and fistula Mesenteric/intra-abdominal abscess (15%-20%) or phlegmon formation Ulcerations and loss of haustration Creeping fat ; Comb sign Prominence of the vasa recta adjacent to the inflamed loop of bowel Transmural extension of inflammation across the serosa and to engorgement of the hyperemic vasa recta surrounding the inflamed bowel segment Not pathognomic of Crohn disease ; Fat halo sign Infiltration of the submucosa with fat, between the muscularis and the mucosa Confused with the fat ring sign of mesenteric panniculitis Nearly pathognomonic of inflammatory bowel disease (Crohn disease and ulcerative colitis) ; Bowel wall enhancement The result of increased vascular permeability and angiogenesis The most sensitive indicator of active Crohn disease Enhancement can be graded by comparing to the precontrast images Minor increased enhancement Moderate enhancement Marked enhancement No abnormal enhancement: equivalent to normal bowel wall ;Homogeneous; Bowel wall thickness Normal bowel wall thickness： lumen distended， 1-2 mm； lumen collapsed, 3-4 mm Mild: 3-5 mm Moderate: