Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Imaging is critical for detection, diagnosis, staging, and follow-up of colorectal carcinoma (CRC)
Detection : CT colonography, plus stool analysis
Complementary role with standard colonoscopy
Early cancer: Sessile or pedunculated polyp
Advanced cancer: "Saddle" or "apple core" lesion
Circumferential narrowing of bowel lumen, overhanging borders, mucosal destruction
Staging : Helical CT ± MR
Short segment (< 10 cm) asymmetric mural thickening & luminal narrowing
Pericolonic fat infiltration; spread to adjacent organs
Metastases to nodes, peritoneum, liver, ovaries
Tumor recurrence and surveillance : PET/CT
FDG-avid lesions in chest, abdomen, pelvis
Diverticulitis
Ischemic colitis
Infectious colitis with TB or ameba
Ulcerative colitis
Endometriosis
Importance of family history
CRC in 1st-degree relatives (↑ risk 2-3x)
Familial adenomatous polyposis
Accounts for < 1% of all colon cancers)
Hereditary nonpolyposis colorectal carcinoma (Lynch syndrome)
Accounts for 5% of all colon cancers
New treatments for metastatic disease (e.g., resection and ablation) offer hope for cure or prolonged survival
Demands accurate staging and surveillance for recurrence
Colorectal carcinoma (CRC)
Malignant transformation of colonic mucosa
Best diagnostic clue
Short segment colonic wall thickening
Location
Cecum (10%), ascending colon (15%), transverse colon (15%), descending colon (5%), sigmoid colon (25%), rectosigmoid colon (10%), rectum (20%)
Morphology
Early cancer: Sessile or pedunculated polyps
Advanced cancer: Annular, semiannular, polypoid, or carpet tumors
Other general features
Radiology is critical for screening, diagnosis, treatment, and follow-up of CRC
Screening: CT "virtual colonoscopy" is comparable to colonoscopy for cancer detection by experienced observers
On air-contrast barium enema or CT colonography
Early cancer: Plaque-like lesion
Flat, protruding lesion with little elevation of surface
Early cancer: Pedunculated lesion
Short and thick polyp stalk
Irregular or lobulated head of polyp
Advanced cancer: Polypoid lesion (large)
Dependent wall: Filling defect in pool of contrast
Nondependent wall: Etched in white
Advanced cancer: Semiannular "saddle" lesion
Transition to annular carcinoma: Polypoid → semiannular → annular
Convex barium-etched margins (in profile view)
Advanced cancer: Annular "apple core" lesion
Circumferential narrowing of bowel lumen, overhanging borders, mucosal destruction
High-grade obstruction with ischemia: Thumbprinting of dilated proximal colon
Advanced cancer: Carpet lesion
Malignant villous tumor may appear as carpet lesion with minimal protrusion into lumen
Radiolucent nodules surrounded by barium-filled grooves; finely nodular or reticular pattern
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here