Recently, treatment strategy of rectal cancer has undergone a dramatic change. Application of total mesorectal excision and preoperative chemoradiation therapy (PCRT) has become standard procedure for locoregional and locally advanced rectal cancer, respectively. Functional and morphological radiologic evaluation as well as multidisciplinary approach is both essential for planning patient-specific therapy. In other words, the needs for more accurate T-and N-staging and assessment of circumferential resection margin, both before and after PCRT, are increasing rapidly. Although there is no consensus on the role of diagnostic imaging such as endorectal ultrasonography, computed tomography and magnetic resonance imaging (MRI), in evaluation of rectal cancer patient so far, MRI is emerging as an essential imaging modality with superior trssue contrast and multiplanar approach.
Colorectal Neoplasms ; Consensus ; Diagnostic Imaging ; Humans ; Magnetic Resonance Imaging ; Rectal Neoplasms

OBJECTIVETo explore the value of comprehensive application of CT and PET/CT in differential diagnosing mucinous and non-mucinous colorectal adenocarcinoma.

METHODSCT and PET/CT image data of 37 patients with mucinous adenocarcinoma and 50 patients with non-mucinous adenocarcinoma confirmed by pathology in our hospital from January 2010 to December 2012 were analyzed retrospectively. Differences of image were compared between two methods.

RESULTSOn CT, lesion density of pre-contrast, pro-contrast phase and enhancement degree were significantly lower in mucinous adenocarcinoma than those in non-mucinous adenocarcinoma(all P<0.01). Enhancement degree of hypointense area, hypointense area proportion of total lesion, and lymphatic or distant metastasis ratio were significantly higher in mucinous adenocarcinoma than those in non-mucinous adenocarcinoma(all P<0.05). On PET/CT, maximal SUV value of mucinous adenocarcinoma was significantly lower as compared to non-mucinous adenocarcinoma[(8.64±4.34) Bq/L vs. (12.38±5.96) Bq/L, P=0.015].

CONCLUSIONSCT combined with PET/CT provides better valuable information in differential diagnosing between mucinous and non-mucinous colorectal adenocarcinoma and clinical practice.

Adenocarcinoma ; diagnostic imaging ; Adenocarcinoma, Mucinous ; diagnostic imaging ; Colorectal Neoplasms ; diagnostic imaging ; Humans ; Multimodal Imaging ; Positron-Emission Tomography ; Retrospective Studies ; Tomography, X-Ray Computed

Objective To investigate the correlation between CT texture analysis and synchronous distant metastasis in patients with lymph node-negative colorectal cancer. Methods The preoperative CT images of 82 patients with lymph node-negative colorectal cancer were analyzed retrospectively.There were 12 patients with simultaneous distant metastasis and 70 patients without simultaneous distant metastasis.The maximum plane of the lesion on plain scan and portal CT images was analyzed by TexRAD software.When the spatial scaling factor(SSF)was 0 and 2-6,six texture parameters were obtained,and the differences of texture parameters between the two groups were compared.The counting data were analyzed by chi-square test and the measurement data by Mann-Whitney test. Results There was a significant difference in the skewness of SSF=3 between the simultaneous distant metastasis group and the non-synchronous metastasis group on plain CT scan(
Colorectal Neoplasms/diagnostic imaging* ; Humans ; Lymph Nodes/diagnostic imaging* ; Neoplasm Metastasis ; Retrospective Studies ; Tomography, X-Ray Computed

OBJECTIVETo explore the value of computed tomography colonography with low radiation dose combined with the enhanced scanning in the diagnosis of colorectal carcinoma.

METHODSA total of 120 patients with clinical suspected colorectal carcinoma undergoing CT colonography and enhanced scanning were randomly divided into routine dose group and low dose group. Conventional colonoscopy and/or surgical pathology were used as the gold standard. Sensitivity, specificity and Youden's index of colorectal cancer TNM staging accuracy were calculated in two groups. The radiation dose of two groups was compared.

RESULTSFor conventional dose and low dose group, in the diagnosis of colorectal cancer (including cancer and adenoma), the sensitivity was 100% (45/45 and 44/44), specificity was 93.3%(14/15) and 87.5%(14/16), the Youden's index was 0.93 and 0.88. There were no significant differences between two groups in T, N and M staging accuracy preoperatively (P>0.05). The effective radiation dose of low dose group was significantly lower than that of conventional dose group [(15.9 ± 4.3) mSv vs. (21.4 ± 5.5) mSv, P<0.01].

CONCLUSIONLow dose CTC combined with enhanced scanning not only reduces the radiation dose of patients, but can possesses similar value of conventional dose CTC in the early diagnosis and preoperative pathological staging of colorectal cancer.

Colonography, Computed Tomographic ; Colonoscopy ; Colorectal Neoplasms ; diagnostic imaging ; Humans ; Radiation Dosage

Colorectal cancer is a leading cancer in many countries. The glucose metabolic activities of the tumor cells are higher than that of the normal cells. They could uptake much more 2-[18F] Fluoro-2-Deoxy-d-Glucose (18F-FDG), an analogue of glucose, than normal cells do. The physicians can search the lesions via 18F-FDG positron emission tomography (PET). 18F-FDG-PET has higher sensitivity and accuracy in diagnosing the primary lesion, recurrence, liver metastasis and extrahepatic metastasis of the colorectal cancer, compared with the conventional technique. The results of the 18F-FDG-PET often restage the colorectal cancer and even change the treatment plan as 18F-FDG-PET provides more information than traditional technique does. Also, it could be used to follow up the case of the colorectal cancer after operation, systematic chemotherapy and radiotherapy. The current review addresses the metabolism, the clinical application, the shortcomings and the future prospect.
Colorectal Neoplasms ; diagnostic imaging ; Fluorodeoxyglucose F18 ; Humans ; Positron-Emission Tomography ; Radiopharmaceuticals

OBJECTIVETo evaluate the techniques and clinical applications of 16 multislice helical CT in colonic lesions.

METHODSEighty-one patients including 54 colorectal carcinomas, 5 adenomas, 1 non-Hodgkin's lymphoma, 6 inflammatory bowel diseases, and other 15 cases underwent volume scanning using 16 multislice helical CT. Four types of reconstruction included multiple planar reconstruction, shaded surface display, raysum, and CT virtual colonoscopy.

RESULTSComplete colon could be shown in all patients. The lesions' morphology, number, size, location, intestinal cavity, pericolonic changes, and other abdominal organs were satisfactorily shown by CT.

CONCLUSIONSSixteen multislice helical CT colonography is a valuable imaging technique for detecting colonic diseases. It is effective in diagnosis and treatment planning. It can display the portions of colon that is inaccessible at colonoscopy.

Adenocarcinoma ; diagnostic imaging ; Adenoma ; diagnostic imaging ; Adult ; Aged ; Aged, 80 and over ; Colonography, Computed Tomographic ; methods ; Colonoscopy ; Colorectal Neoplasms ; diagnostic imaging ; Female ; Humans ; Inflammatory Bowel Diseases ; diagnostic imaging ; Male ; Middle Aged ; Tomography, Spiral Computed ; methods

OBJECTIVETo compare the difference in CT manifestations between primary colorectal mucinous adenocarcinoma and signet ring cell carcinoma in order to improve radiologic diagnosis.

METHODSClinicopathological data and CT findings of 109 patients with colorectal mucinous adenocarcinoma and 46 patients with primary colorectal signet-ring cell carcinoma confirmed by surgery and pathology from March 2008 to February 2015 in the Tumor Hospital of Yunnan Province were retrospectively collected. Differences in age, gender, tumor location, length and thickness of the involved intestinal wall, thickening pattern of the intestinal wall, lesion density, calcification, contrast-enhanced form, peri-intestinal invasion, occurrence of intestinal obstruction and metastasis of other organs were compared between the two groups.

RESULTSAmong 109 patients with colorectal mucinous adenocarcinoma, 68 were men and 41 were women with a mean age of (56.8±15.4) years. Among 46 patients with primary colorectal signet-ring cell carcinoma, 26 were men and 20 were women with a mean age of (42.9±15.6) years. Compared with mucinous adenocarcinoma group, signet-ring cell carcinoma group showed more concentric bowel-wall thickening[93.5%(43/46) vs. 81.6%(89/109), χ=9.19, P=0.030], higher lesion density [(42.0±3.0) Hu vs. (28.5±1.5) Hu, t=37.30, P=0.000], more marked enhancement [54.3%(25/46) vs. 12.8%(14/109), χ=35.21, P=0.000], less vast-low-density region in enhanced CT imaging[2.2%(1/46) vs. 45.0%(49/109), χ=73.31, P=0.000] and more severe peri-intestinal invasion [41.3% (19/46) vs. 17.4%(19/109), χ=10.25, P=0.006]. Calcification was found in 18.3%(20/109) of mucinous adenocarcinoma cases, but was not found in signet-ring cell carcinoma cases (χ=9.69, P=0.002). Target ring sign in contrast-enhanced scan was observed in 15.2%(7/46) of signet-ring cell carcinoma cases, while in none of mucinous adenocarcinoma cases (χ=17.37, P=0.000). There were no statistically significant differences in lesion location, length and thickness of the involved intestinal wall, occurrence of intestinal obstruction, lymph node metastasis, liver or peritoneum metastasis between two groups(all P>0.05).

CONCLUSIONSSignet-ring cell carcinoma is often found in younger patients, whose CT manifestation is characterized by the target ring sign in contrast-enhanced scan, while primary colorectal mucinous adenocarcinoma is often in older patients, whose CT manifestation is characterized by calcification in unenhanced scan and low density region in enhanced CT show.

Adenocarcinoma, Mucinous ; diagnostic imaging ; pathology ; Adult ; Age Factors ; Aged ; Calcinosis ; diagnostic imaging ; pathology ; Carcinoma, Signet Ring Cell ; diagnostic imaging ; pathology ; China ; Colorectal Neoplasms ; diagnostic imaging ; pathology ; Female ; Humans ; Male ; Middle Aged ; Neoplasm Staging ; Retrospective Studies ; Tomography, X-Ray Computed ; methods

Adenomatous Polyps ; diagnostic imaging ; etiology ; Aged ; Aged, 80 and over ; Colorectal Neoplasms ; diagnostic imaging ; etiology ; Female ; Humans ; Liver ; diagnostic imaging ; Male ; Middle Aged ; Non-alcoholic Fatty Liver Disease ; complications ; diagnostic imaging ; Ultrasonography

Colorectal carcinoma is a common lethal disease with signs and symptoms that may be nonspecific. Computed tomography (CT) of the abdomen and pelvis with or without contrast is frequently performed for various general abdominal complaints, but unlike CT colonography, the large bowel may not be optimally prepared for evaluation. As such, careful and diligent assessment of the non-prepared colon in all CT images of the abdomen and pelvis is important, as it ensures that incidental colorectal malignancy is not missed, especially in older patients. This article gives an overview of multidetector CT imaging signs and subtle clues to aid in the diagnosis of colorectal carcinoma, as well as their pitfalls.
Colonic Polyps ; pathology ; Colonography, Computed Tomographic ; Colorectal Neoplasms ; diagnosis ; diagnostic imaging ; Diagnosis, Differential ; Humans ; Incidental Findings ; Pelvis ; diagnostic imaging ; Radiography, Abdominal ; Tomography, X-Ray Computed

OBJECTIVETo observe the lower gastrointestinal mesenchymal tumors CT virtual endoscopy and pathology, and to explore its possible mechanism.

METHODSSelect 80 patients suspected colon gastroenterology treat in the hospital gastroenterology department, randomly divided into experimental group and control group, 40 cases in experimental group were given CT virtual endoscopy and pathological check, the control group received conventional colonoscopy and pathological check, and all the results compared with the pathological results.

RESULTSCompared with the pathological test results, consistent rate with the experimental group reached 94.73%, the same rate was 92.85% in control group. The difference was not statistically significant (P > 0.05).

CONCLUSIONSCT virtual endoscopy can quickly image and draw detailed information, and can improve the sensitivity and specificity of cancer diagnosis greatly. Clinically, CT virtual endoscopy have the same function as colonoscopy, can replace colonoscopy, can be important complement of electronic colonoscopy by those who cannot tolerate electronic colonoscopy or have contraindications. Its value is worth taking a step forward in-depth study.

Adult ; Aged ; Colonoscopy ; Colorectal Neoplasms ; diagnostic imaging ; pathology ; Endoscopy, Gastrointestinal ; methods ; Female ; Humans ; Male ; Mesenchymoma ; diagnostic imaging ; pathology ; Middle Aged ; Tomography, X-Ray Computed