Objective To explore the relationship between ileocolonic lesions and perianal fistulas of Crohn's disease as sessed by CT enterography (CTE).Methods Totally 28 patients with initial diagnosis of active ileocolonic lesions of Crohn 's disease were collected,16 with perianal fistula and 11 without perianal fistulas.All patients underwent CTE and pelvic MRI.Total number of lesions,minimum length between every two lesions in colon wall and maximum length of colonic le sions were calculated.The rank sum test was performed respectively.Results Lesions of 14 patients (14/16,87.50％) in perianal fistulas group located in left colon or rectum,while lesions of 6 patients (6/12,50.00 ％) in non-perianal fistulas group located in left colon or rectum,the difference was statistically significant (Z=-2.135,P＜0.05).The mean number of lesions in patients with perianal fistulas was 3.06,while in patients without perianal fistulas was 2.91,there was no statistical difference (P＞0.05).The maximum length of colonic lesions in patients with perianal fistulas was (12.79± 8.30)cm,while in patients without perianal fistulas was (7.04± 3.09)cm,and there was no statistical difference(P＞ 0.05).The minimum length hetween every two lesions in patients with perianal fistulas was (5.23±2.98)cm,while in pa tients without perianal fistulas was (8.44 ± 2.87) cm,the difference was statistically significant (Z =-2.095,P＜ 0.05).Conclusion Crohn's disease complicated with perianal fistulas has relationship with lesion location and smaller length intervals between two lesions in colon wall,and has no relationship with total number of lesions and maximum length of colon lesions.

Objective To analyze retrospectively the impact of different heart rates on image quality and radiation dose of coronary angiography using 640-slice dynamic volume CT.Methods A total of 461 patients with suspected coronary artery disease or referred to health check underwent coronary angiography with 640-slice dynamic volume CT.Two groups were created according to their heart rates:Group A had heart rate < 65 beats per minute (n=337)and Group B had heart rate between 65 to 122 beats per minute (n=124).Image quality was assessed by analyzing the 1 5 segments of the main coronary branches using 3-grade scale (grade I-good,grade Ⅱ-acceptable,grade Ⅲ-poor).Effective radiation dose was also evaluated.Results Patients in both A group and B group performed successful CT coronary angiography with a total of 6 91 5 coronary segments.Among them,coronary segments that could be evaluated reliably accounted for 94.5% (6 535/6 91 5)while 5.5% (380/6 91 5)were too small (≤1.5 mm)to be assessed. For the image quality,Group A and Group B had grade I in 90.5% (305/337)vs 74.2% (92 /124),grade Ⅱ in 9.5% (32/337)vs 21.0% (26 / 124)and grade Ⅲ in 0 % (0 / 337 )vs 4.8% (6 / 124),respectively.Image quality was significantly different be-tween Group A and Group B (P <0.001).In addition,32 patients (9.5%)in Group A had slight cardiac motion artifacts but with-out affecting image quality,whereas 26 patients (21.0%)in Group B had higher degree of cardiac motion artifacts thus graded as grade Ⅱ.Stair-step artifacts were not found in all patients.The effective radiation dose was higher in Group B than in Group A by 32.05%(7.91±0.34 mSv vs 5.99±0.17 mSv).Conclusion Coronary angiography using 640-slice dynamic volume CT can guarantee excellent image quality when heart rate < 65 beats per minute.Although the image quality would decrease in some extent it is still diagnostic when heart rate is between 65 to 122(include 65 and 122)beats per minute.

OBJECTIVETo evaluate the application of low-dose CT enterography with adaptive iterative dose reduction(AIDR) technique in diagnosing Crohn's disease.

METHODSRetrospective analysis was performed on 26 patients diagnosed as Crohn's disease by the multidisciplinary team in our hospital. Low-dose CT enterography with 640-slice MDCT was performed on these 26 patients using adaptive iterative dose reduction(AIDR) technique. Characteristics of Crohn's disease in CT enterography images were independently analyzed by two radiologists who were experienced in Crohn's disease with calculating the total radiation dosage.

RESULTSThe radiation dosage of 26 patients ranged from 5.58 to 12.90 [mean (9.00±2.00)] mSv, which was lower than conventional scan (around 15 mSv) known from the literatures. According to the images of CT enterography of 26 cases, bowel wall thickening with abnormal enhancement and lymphadenectasis were found in 25 cases with total 109 segmental bowel wall thickening. Among 25 thickening cases, enterostenosis was found in 16 cases, stratification enhancement in 12 cases and comb sign in 14 cases. Besides, it was found that 8 cases with hyperdense fat on the mesenteric side, 7 cases with intestinal fistula, 6 cases with abdominal cavity abscess, and 3 cases with anal fistula.

CONCLUSIONCT enterography of Crohn's disease with adaptive iterative dose reduction technique is an effective method to evaluate Crohn's disease without compromising image quality with reduced radiation dosage.

Crohn Disease ; diagnostic imaging ; Humans ; Intestinal Fistula ; Radiation Dosage ; Rectal Fistula ; Retrospective Studies ; Tomography, X-Ray Computed ; methods

Objective:To investigate the MRI differences between locally advanced rectal mucinous adenocarcinoma and non-mucinous adenocarcinoma before and after neoadjuvant chemoradiotherapy (NCR).Methods:A retrospective cohort study was conducted to collect the clinical and imaging data of 165 patients with locally advanced rectal adenocarcinoma treated by NCR combined with surgery from October 2016 to October 2019 in the Sixth Affiliated Hospital of Sun Yat-sen University, 36 cases were rectal mucinous adenocarcinoma and 129 cases were non-mucinous adenocarcinoma. The image features of the two groups before and after NCR were evaluated based on MRI, including the length and thickness of the tumor, the distance from the lower edge of the tumor to the anal edge, T stage, N stage, involvement of mesorectal fascia (MRF) and peritoneal reflux. The difference of NCR and the change of MRI characteristics after NCR were compared by independent sample t test, Mann-Whitney U test or χ 2 test. The accuracy of MRI re-staging after NCR was evaluated according by postoperative pathological staging results. Results:Before NCR, there was significant difference in length of tumor between mucinous adenocarcinoma and non-mucinous adenocarcinoma groups ( P=0.044), there was no significant difference in the distance from the lower edge of the tumor to the anal edge, thickness of the tumor, T stage, N stage, involvement of MRF and peritoneal reflux (all P>0.05). After NCR, in patients with non-mucinous adenocarcinoma, the distance reduction from the lower edge of the tumor to the anal edge, the length reduction of the tumor, the thickness reduction of the tumor, the T-stage decline rate were significantly higher than those in the mucinous adenocarcinoma group (all P<0.05). The N-stage decline rate of mucinous adenocarcinoma was higher than that in non-mucinous adenocarcinoma group ( P=0.008). After NCR, MRI overestimated T staging of patients with both mucinous adenocarcinoma and non-mucinous adenocarcinoma compared with pathological T-stage ( P<0.001). In patients with mucinous adenocarcinoma, MRI overstated the N-stage than pothology ( P=0.001). Conclusions:There is different sensitivity of mucinous adenocarcinoma and non-mucinous adenocarcinoma to NCR. Patients with non-mucinous adenocarcinoma benefit more from the efficacy of NCR. The accuracy of MRI in re-staging of rectal mucinous adenocarcinoma and non-mucinous adenocarcinoma after NCR needs to be improved.

Objective:To investigate the application value of baseline MRI multi-parametric imaging radiomics in prediction of neoadjuvant chemoradiotherapy (NCR) efficacy of rectal mucinous adenocarcinoma (RMAC).Methods:Retrospective analysis was performed in the Sixth Affiliated Hospital of Sun Yat-sen University from August 2012 to October 2018. A total of 79 patients were included in this study, including 52 males and 27 females, aged 20-78 years (median age 52 years). According to the classification criteria of pathological regression, all patients were divided into NCR responsiveness group ( n=31) and nonresponsiveness group ( n=48). And 701 imaging features of T 2WI, diffusion weighted imaging (DWI) and enhanced T 1WI images of baseline MRI were extracted, and feature subsets were selected by repeatability analysis and feature dimensionality reduction to construct the radiomics prediction model. The tumor features from baseline MRI between the NCR responsiveness group and the nonresponsiveness group were compared, and the features of P<0.05 were combined with the radiomics to construct a model. Using pathology as the gold standard, the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficiency of the prediction model, and the area under the curve (AUC), 95% confidence interval, sensitivity and specificity were calculated, and the DeLong test was used to compare the diagnostic efficacy of different prediction models. Results:By comparing the conventional tumor imaging characteristics of the NCR responsiveness group and the nonresponsiveness group, the differences in lymph node stage and mucinous nodule status between the two groups were statistically significant (χ2 =6.040, 5.870, P<0.05). The AUC of ROC curves based on T 2WI, DWI, and enhanced T 1WI radiomics were 0.816, 0.821, and 0.819, respectively, which were higher than those of conventional tumor characteristics (lymph node staging, mucinous nodule status) (AUC=0.607), and the differences were statistically significant ( Z=-2.391, -2.580 and -2.717, P<0.05). Among the joint prediction models of T 2WI, DWI and contrast-enhanced T 1WI radiomics and conventional tumor features, the DWI combined model had the largest AUC (0.843), and there was no statistically significant difference between the three combined models (all P>0.05). Conclusion:The baseline T 2WI, DWI, and contrast-enhanced T 1WI radiomics model can be used to predict the NCR efficacy of RMAC, which is better than the predictive efficacy of conventional features, and the combination with conventional features can further improve the predictive efficacy.

OBJECTIVETo investigate the value of MRI with CUBE sequence in early evaluation of the efficacy of neoadjuvant therapy (NAT) for locally advanced rectal cancer.

METHODSInclusion criteria: (1) rectal cancer proven by biopsy; (2) locally advanced rectal cancer (T3-4 or positive lymph nodes) with distance from lower edge of tumor to anal verge within 12 cm diagnosed by MRI before NAT; (3) acceptance of NAT treatment regulations and completion of NAT; (4) completion of routine MRI scan and CUBE scan before and after 2-course NAT chemotherapy (including new neoadjuvant chemotherapy and chemoradiotherapy); (5) completion of surgery 6-8 weeks after NAT; (6) exclusion of any previous NAT due to rectal malignant tumor or other tumors; (7) exclusion of poor image quality of preoperative routine MRI insufficient for rectal cancer staging or of CUBE image insufficient for tumor volume measurement. Fifty patients with advanced local rectal cancer were recruited in our hospital from February 2014 to January 2016. All the patients underwent MRI before and after 2-course neoadjuvent therapy. Tumor volume on CUBE were measured and the volume changes were calculated: volume difference= pre-treatment volume-post-treatment volume, volume change rate= (pre-treatment volume-post-treatment volume)/ pre-treatment volume. All the patients were categorized into sensitive and non-sensitive group according to postsurgical pathology. Comparisons were made between both groups before and after therapy. ROC curve was used to evaluate the value of CUBE-associated parameters in predicting the efficacy of rectal cancer.

RESULTSAmong enrolled 50 patients with rectal cancer, 31 were male and 19 were female, with mean age of 49.1 years (range 21 to 70 years). T-staging by MRI before NAT was T2N1-2 in 1 case, T3 in 43 cases, T4 in 6 cases. The number of patients after NAT from tumor regression grading (TRG) 0 to TRG3 was 14, 13, 18, 5, respectively. The sensitive group and insensitive group were 45 cases and 5 cases. Mean tumor volume before and after preoperative 2-course NAT was 18.70 (4.14 to 91.77) cmand 9.26 (1.02 to 52.58) cm, respectively, whose difference was significant (U=-5.826, P<0.001). Both measure values of overall tumor volume before and after preoperative NAT between sensitive group and insensitive group did not show significant differences(all P>0.05). While sensitivity group had significantly higher volume difference and change rate compared to insensitive group [ (11.90±10.01) cmvs. (0.65±3.93) cm, P=0.005; 0.45±0.28 vs. 0.09±0.36, P=0.010]. ROC curve revealed that the optimal cutoff value of accurate identification of patients with NAT sensitive was 1.96 cmfor volume difference with sensitivity 86.7% and specificity 80%, and 0.06 for volume change rate with sensitivity 93.3% and specificity 60%.

CONCLUSIONMRI CUBE can predict the efficacy of NAT for early rectal cancer patients accurately and sensitively through the detection of tumor volume change before and after NAT.