64-slice Spiral CT in Grading of Colorectal Adenoma and Diagnosis of Adenocarcinoma / 中国医学影像学杂志

ABSTRACT

PurposeTo evaluate 64-slice spiral CT in grading of colorectal adenoma and in the diagnosis of adenocarcinoma.Materials and Methods Sixty-eight cases of pathology confirmed colorectal adenoma were retrospectively reviewed to analyze CT performance including the location, size, shape and their relationship with adjacent structures and degree of enhancement in arterial, venous and delayed phase. The difference of CT attenuation value before and after enhancement (△CT value) in arterial, venous and delay phase of different pathological types and different levels of adenomas were compared.Results Among 68 lesions, 16 were villous adenomas, 42 were tubulovillous adenomas and 10 were tubular adenomas. Villous adenomas and tubulovillous adenomas were characterized by wide base, villous-like with gyral or frond pattern enhancement in arterial phase. There was a layer of low density mucus covering the surface. Tubular adenomas were featured as narrow base, nodular in shape with homogeneous enhancement.△CT values in each phase between villous adenomas and tubular adenomas showed statistically significant difference (arterial phaset=2.56,P<0.05; venous phaset=3.22,P<0.05; delayed phaset=2.48,P<0.05), however no significant difference was shown between villous and tubule villous adenomas or between tubulovillous and tubular adenomas. Adenocarcinomas showed creeping-type growth along the intestinal wall with a cluster of vessels adjacent to the tumor or enlarged lymph nodes.△CT values in each phase between non-dysplasia group and carcinoma group showed statistically significant difference (arterial phaset=2.49,P<0.05; venous phase t=2.69,P<0.05; delayed phaset=2.75,P<0.05), however no significant difference was shown between non-dysplasia group and dysplasia group or between dysplasia group and carcinoma group. Using 50 HU of△CT value in artery phase as standard, the sensitivity and specificity for diagnosis of adenocarcinomas were 76.92% and 70.91%, respectively.Conclusion CT findings of different pathological types of colorectal adenomas and adenocarcinomas are characteristic and useful in preoperative diagnosis and treatment planning.