CT Findings Of Gastrointestinal Stromal Tumors And Correlation With Pathology

Gastrointestinal stromal tumors(GIST) is a kind of mesenchymal tumors in digestive tract which may occur from esophagus to rectum.It is made up of undifferentiated,spindle or epithelioid cells.Prior to this,It is mainly diagnosed as leiomyoma,cellular leiomyoma,leiom yoblastoma and leiomyosarcoma by sector of pathology.However,with the development of immunohistochemical methods and molecular biology methods,the medical profession increase their awareness gradually,particular in the understanding of genetic characteristics of this tumors,meanwhile pathological studies have confirmed that the majority of GIST cases have no or only a few characteristics of incomplete differentiation,a small number of cases have the characteristics of differentiation as complete smooth muscle,nerve,autonomic nerve and ganglion cells.It is more difficult to make an early diagnosis of Gastrointestinal stromal tumors,to make a definite diagnosis rely on the pathological diagnosis,However,to conduct a comprehensive analysis using a variety of imaging methods can provide great help in determination of biological behavior of gastric stromal tumor,it is beneficial for medical clinic. Study Objective:To explore the application value of multi-slice spiral CT in diagnosis of gastrointestinal stromal tumor,this paper collected 59 cases of patients who were diagnosed as GIST in our hospital during November 2007 to January 2009,imaging features of gastrointestinal stromal Tumor in multi-slice spiral CT were analyzed retrospectively,to conduct controlled study in pathologic and clinical research.Material and Methods:Collected 59 patients with Confirmed by surgery and pathology gastrointestinal stromal tumors from November 2007 to January 2009.32 cases of stomach;16 cases of small intestine;3 cases of retroperitoneal;8 cases of abdominal and pelvic.33 were male and 26 were female.The mean age was 59.39 years,range from 35-86 year old.59 cases of this group of clinical manifestations, 21 cases of abdominal pain;14 cases of distension;10 cases of melena;14 cases of abdominal mass,and 4 cases of symptoms that occurred at the same time accompanied by hematemesis;.59 cases of patients had CD43 and/or the expression of CD117.59 cases of this group,both by pathology and immunohistochemistry confirmed,in which case,57 cases of spindle cell tumor,1 case was necrosis and spindle cell tumors,1 cases of mesenchymal tumors.Very low degree of 10 cases of malignant potential;low-grade malignant potential 13 cases;18 cases of moderate malignant potential;18cases of highly malignant potential.56 cases of positive CD117,weakly positive in 2 cases,focal positive 1 cases;CD34-positive 50 cases,nine cases of negative;SMA-negative 42 cases,13 cases positive,4 cases of focal positive;Desmin-negative 58 cases,positive 1 cases;S-100 negative 57 cases, 2 cases of positive.The use of GE Lightspeed16 machine-slice spiral CT scan were performed and three enhanced scanning,patients fasted for more than 4-6 hours,10 minutes before scanning intramuscular 654-2 20mg,stomach scan takes oral examination before the 15min warm water 800-1000ml stomach cavity filling;need to scan the colon for bowel cleansing in advance,and took office after filling the colon anus Road 1000ml water;check the small intestine to be 2～3 hours in advance of oral slow warm water or 2.5%isotonic mannitol 1000～1500ml cavity filling the small intestine;From supine patients,scanning from the diaphragm area iliac spine to the top level,after the first CT scan done,scanning parameters of thickness 5.0mm,layers from 5.0mm;the use of high-pressure injection by the elbow before the intravenous injection of non-ionic contrast agent 100ml,injection flow rate of 4ml/s,injection of contrast agent in 25s,60s,120s,respectively, collected arterial phase,venous phase,a balanced view of the data.Through the statistics of cases through the general condition of patients,lesion location,size, growth pattern,shape,density,enhanced features,metastasis and invasion of adjacent organs analyzed,and results were compared with the pathological studies.Results:in 50 single cases,31 cases were confirmed in gastric cases, accounting for 62%,in which 4 cases presented with gastric antrum,5 cases with lesser curvature of gastric body,8 cases with greater curvature of gastric body,4 cases with gastric posterior wall,1 case with gastric cardia,5 cases with gastric fundus;16 cases were confirmed in small intestine cases,accounting for 32%,in which 1 case presented with distal ileum,1 case with jejunum,9 cases with duodenal,the remaining 5 cases of intestinal lesions and of continuation of the small intestine and intestinal cavity inside or outside and inside and outside the prominent;3 cases were confirmed in retroperitoneal,accounting for 6%.In 9 multiple cases,1 case was confirmed in gaster,8 cases were in abdominal and pelvic cavity.Focal length of these 59 cases were between 0.5～19.2cm,26 cases less than 5cm,33 cases more than 5cm.25 cases with regular form and clear boundaries;34cases with irregular form,unclear boundaries in adjacent structures or fuzzy in edge,.In CT scan group,21 cases with uniform density,38cases with non-uniform.In the prim-ary group of 59 cases of gastrointestinal tract to the growth of cavity(submucosal type) of 11 cases(18.6%);18 cases of extra-cavity growth(30.5%);cavity/external growth(muscle intramural type) 19 cases(32.2%); 11 cases of gastrointestinal app-earance(18.6%).CT see all GIST patients had varying degrees of strengthening,no-tably the strengthening(CT value increased>60Hu) a total of 27 cases(45.8%),no enhanced(CT value <60Hu) a total of 32 cases(54.2%);even enhanced in 21 cases(35.6%);heterogeneous enhancement in 38 cases(64.4%);there are nine ca-ses(15.3%) in order to strengthen the arterial phase,and the majority of venous p-hase enhanced arterial phase was significantly higher than that.8 cases presented with cystic low-density in tumor center,2 cases with cystic low-density in calcifi-cation combined,3 cases with calcification in tumor center,1 case with cystic deg-eneration and hemorrhage; 3 cases with intrahepatic metastasis,1 case with liver combined pelvic metastasis,1 case with lymphaden metastasis,(4 lesions cases were confirmed in inflammatory changes by pathological,while 1 case was con-firmed in metastasis).Violation of tumor was happened to 14 cases(23.7%),it was unclear on the boundaries of surrounding organs and some arteria,which lead inv-olvement of organ thicker wall or unclear boundaries,even disappeared envelope,mesenteric or the surrounding layer of fat increase in density,or appeared density shadow in irregular strip of soft tissue,enhanced slightly after enhancement.In enhanced CT result,1 case was presented with abnormal artery,1 case with blood supply by left gastroepiploic artery,and 2 cases with blood supply by mesenteric artery branches.Conclusion:16-slice spiral CT plays an important role in detecting gastrointestinal stromal tumor,in CT scan;tumor is regular in density of soft tissue, nodular appearance,type of round,oval-shaped or irregular-shaped.The body of tumor prone to mucinous,hemorrhage,necrosis and cystic degeneration which will result in an uneven density,visible spots of calcification can be seen in tumor. Enhanced CT with different ways will lead different extent,the CT performance of Gastrointestinal stromal tumors is closely related to its histopathological,spiral CT is of certain value on determine of tumor as well as the relationship between surrounding organs and availability of transfer,but have difficulty in determining the benign and malignant,in current CT diagnosis,the benign or malignant can be based limited to the size of tumor,the results need to be contrasted with clinical pathology.CT scan achieves with high speed,it can be completed within a breath-hold operation,it is a non-invasive,non-painful techniques.Through reconstruction of thin-layer of spiral CT,MPR reconstruction can be rotated in workstation arbitrarily,to observe lesion from different angles,size,morphology, internal structure,growth characteristics and gastric wall can be seen clearly,it can improve diagnosis of lesions greatly,and provide great help in clinical treatment as well as the Choice of surgical procedures.