Multi-slice spiral computerized tomography findings of colorectal cancer with chronic schistosomiasis / 中华传染病杂志

ABSTRACT

Objective To retrospectively analyze computerized tomography (CT) imaging features of colorectal cancer with chronic schistosomiasis in order to improve the diagnostic accuracy.Methods Eighty patients whose diagnosis was pathologically confirmed as colorectal cancer with schistosomiasis were collected from Tongji Hospital and Kunshan Chinese Medicine Hospital from January 2007 to December 2012.All the patients underwent abdominal plain CT and contrast-enhanced CT scan.The lesion location,morphology,size,calcification features,enhancement patterns and cancer metastasis were evaluated and compared by two radiologists who were blind to the diagnosis.Twenty colorectal cancer cases without schistosomiasis from the same area were also collected as controls.Results CT imaging showed that the tumors all occurred in the colon and rectum in 80 patients,mainly in colon descendens,colon sigmoideum and rectum.The lesion was characterized by irregular bowel wall thickening with soft tissue masses,and the average length of impaired intestine was (21.35 ± 4.50) cm.The lesions were solitary in 68 cases (85.0％) and were multifocal in 12 cases (15.0％).Linear,spotty and small patchy calcifications were seen in all the patients,with margins unclear in 59 patients (73.8％) and margins clear in 21 patients (26.2％).Early phase enhancement was seen in 68 cases (85.0％),of which 45 cases (56.2％) had homogenous enhancement and 23 cases (28.8％) had heterogeneous enhancement.Late phase enhancement was seen in 73 cases (91.2％) and necrosis was hardly seen.Only two cases (2.5％) had liver metastasis without lymphatic metastasis.All the 20 colorectal cancer cases without schistosomiasis presented with single lesion,which was characterized by irregular bowel wall thickening and local ulcer.The average length of impaired intestine was (6.90±3.40) cm.No calcification was seen in these lesions.All cases had early phase lesion with remarkable heterogeneous enhancement with low density necrotic area.The late phase enhancement was decreased.Four cases (20.0％) had liver metastasis.Compared to cases without schistosomiasis,cases with schistosomiasis tended to have multifocal (x2=100,P=0.000) and longer lesion (t=45.506,P=0.000),and more calcification (x2=100,P=0.000).The early phase heterogeneous enhancement was less frequent (x2 =88,P=0.000) and late phase enhancement was more frequent (x2=100,P=0.000).The liver metastasis rate was significantly lower (x2 =8.688,P =0.014).Conclusions The CT imaging of colorectal cancer with schistosomiasis is characterized by calcifications inside the tumor with obscured margins and multiple intestinal segments involvement.Hematogenous metastasis and lymphatic metastasis are rarely seen.