The Diagnosis Value Of MR Imaging In Preoperative T Staging Of Rectal Carcinoma

Background and purposeRectal carcinoma is one of the most common malignant tumor of digestive system.colorectal cancer for Accounting50%～70%. The morbidity and mortality in Europe and the United States and other Western countries in ranked second. In China, Morbidity and mortality of colorectal cancer ranked fourth. Colorectal cancer showed an upward trend in the incidence of at home and abroad. The incidence of colorectal cancer in China is much higher than abroad, and the patients are relatively younger. Lower cancer incidence site the majority of its features and ulcerative lesions. Rectal cancer surgical resection, preoperative and postoperative radiotherapy and chemotherapy. For rectal cancer surgical resection is the most important method. In recent years, with the conversion of rectal cancer treatment modalities, radiotherapy and chemotherapy have become an important means in the comprehensive treatment of rectal cancer. The local recurrence rate of rectal cancer after surgical treatment was3%-32%. Successful resection of the tumor mainly rely on accurate Preoperative staging and appropriate surgical approach.MR dynamic enhancement curve and ADC values may reflect the degree of differentiation of colorectal cancer. The research in this area is relatively rare, while the magnetic resonance high-resolution in rectal cancer staging applications is more common, and the diagnosis accuracy rate of rectal cancer T-staging is higher. In this study, we used MRI for T staging of rectal cancer research. Materials and Methods73cases of primary colorectal cancer patients confirmed by pathology in our hospital from July2010to May2011, retrospective analysis of preoperative pelvic MR images.45cases were male and28females, aged from30to83years old, and average is58.78±12.81. Middle-differentiated adenocarcinoma of the rectum in59cases, and six poorly differentiated adenocarcinoma cases, one high-differentiated adenocarcinoma case.1poorly differentiated adenocarcinoma case.2cases differentiated with part of mucinous adenocarcinoma,4cases mucinous adenocarcinoma, Seven cases of upper rectal cancer,35cases of rectal middle of cancer, rectum cancer in6cases under paragraph25cases of rectum cancer. With mass in8cases,45cases of ulcer and20infiltrating cases. Surgical procedure:Dixon surgical approach in53cases,20cases of the Miles surgical approach. Cases of this study group clinical manifestations of blood stools, constipation, abdominal pain, abdominal discomfort. All cancer patients, MR examination was taken before any radiotherapy, chemotherapy and without stimulus rectum exam. The application of fast spin echo (the turbo spin-echo TSE) sequence of the whole pelvic scan. First sagittal T2WI scan, axial SE sequence of the conventional sequence of T1WI, T2WI of FSE sequence scanning. Fat suppressed coronal FSE sequence T2WI scanHigh-resolution the T2WI scanning, DWI, axial check Diffusion sensitive factor b values taken0,1000s/mm2, Dynamic contrast-enhanced scan.All scanned images are Syngo workstation for analysis and processing,Refer to the staging system for colorectal cancer clinical TNM, By two physicians were double-blind method for the observation of film-reading, Three methods on MRI regular sequence+DWI of MRI regular sequence+DWI+DCE-MRI, MRI, conventional sequence+DWI,+resolution MRI,T staging of rectal cancer, then reached a consensus. T stage refers to a violation of the tumor on the bowel wall and adjacent organs. Using Pathological staging as the gold standard to evaluate the consistency of the three methods in the preoperative T stage and pathological stage.Using SPSS17.0statistical analysis software analyses the parameters of benign and malignant rectal carcinoma. ResultConventional MRI sequences, of MRI regular sequence+DWI+DCE-MRI, its accuracy of MRI conventional sequence+DWI+high-resolution MRI, three methods of rectal cancer T stage and pathological findings were69.9%、76.7%、82.3%、93.2%.The sensitivity, specificity, positive predictive value, and negative predictive value of MRI in detecting invasion through the bowel wall were97.9%,85.2%,93.2%,95.7%,88.5%, Kappa value is0.895.Differentiated adenocarcinoma in this group of patients more, Which smaller ADC value of0.511x10-3mm2/s, Larger ADC value is1.493x10-3mm2/s, The mean ADC value of0.937±0.190×l0-3mm2/s, differentiated adenocarcinoma Poorly, Which smaller ADC value of0.740×10-3mm2/s, Larger ADC value is1.015x10-3mm2/s, The mean ADC value of0.9034±0.108×10-3mm2/s;Mucinous carcinoma less, Which smaller ADC value of1.054×10-3mm2/s, Larger ADC value is1.348×10-3mm2/s, The mean ADC value of1.189±0.124×10-3mm2/s.Rectal magnetic resonance time-signal intensity curve (TIC) is divided into three types:Type Ⅰ is slowly rising; type II speed1downhill type; III type platform type, the curve between type Ⅰ and type Ⅱ; Summary of the characteristics of73patients with rectal cancer, dynamic contrast enhancement curve analysis to investigate the performance characteristics and diagnostic value. I type curve for this study was13.7%, type II curve for15.1%, Ⅲ-shaped curve63.0%.Conclusion1. The conventional MRI sequences+DWI rectal cancer T staging is of limited value.2. MRI regular sequence+DWI+high-resolution MRI of rectal cancer T stage and pathological control high consistency, Rectal cancer T staging check sequence combinations.3. MRI dynamic contrast enhanced CT of great value to the qualitative diagnosis of rectal cancer, but can not significantly improve the preoperative T staging accuracy.