PURPOSE: To retrospectively determine the computed tomographic (CT) signs a
ssociated with diverticulitis or colon cancer, and to prospectively apply t
hese signs in the differentiation of these diseases.
MATERIALS AND METHODS: Fifty-eight CT scans in cases of proved diverticulit
is (n = 27) or colon cancer (n = 31) were evaluated retrospectively by radi
ologists (blinded to the proved diagnosis);for the presence or absence of p
reviously reported CT findings. These findings were correlated with the pat
hologic or final clinical diagnosis. The retrospective findings were applie
d in a prospective evaluation with a new set of 72 CT scans. The same five
radiologists rendered a diagnosis according to a five-point confidence scal
e from definitely benign to definitely malignant. Individual and consensus
readings were correlated with the final diagnosis.
RESULTS: Retrospectively, pericolonic inflammation (P < .01)and segment inv
olve; ment greater than 10 cm (P < .012) were the most significant findings
for diverticulitis; pericolonic lymph nodes (P < .0001) and luminal mass (
P < .003) were the most significant findings for colon cancer. Prospectivel
y, an unequivocal diagnosis was made correctly in 16 (40%) of 40 cases of d
iverticulitis and 21 (66%) of 32 cases of colon cancer.
CONCLUSION: When there are no pericolonic lymph nodes adjacent to a segment
of colonic wall thickening, with pericolonic inflammatory changes, the mos
t likely diagnosis is diverticulitis. When pericolonic lymph nodes are pres
ent, with or without pericolonic edema, the most likely diagnosis is colon
cancer.