Significance Of Pre-operation Diagnosis Of Large Intestinal Cancer On MSCT

Objective:1,To explore the value of MSCT on pre-operation diagnosis and staging in largeintestinal cancer.2,To evaluate the difference between 4-MSCT scanner and 16-MSCT scanner onpre-operation diagnosis of large intestinal cancer.Material and Methods:111 patients diagnosis of non-M stage large intestinal cancer (16-MSCT scan for60 eases, 4-MSCT scan for 51 cases) proved by surgical pathology wereretrospectively reviewed, while other 18 patients with M stage large intestinal cancerwas proved by enteroscope. Enhanced MSCT was performed in all patients. Aftertaking purgative last night and enteroclysis in the morning before examination, 654-2was given by intramuscular injection and iodine allergy test was performed.Compound Diatrzoatc Meglumlne solution(150-250ml) or gas(1000-1500ml) waspumped into the patients from anus. Ten patients took gas enteroelysis. All CTexaminations were performed without breath with a slice collimation of 5.0-6.0 mm,pitch of 1.0, reconstruction interval of 1.0-2.0mm and reconstruction overlap interval0.5-1.0mm for 16-MSCT scan, reconstruction interval of 3.0mm and reconstructionoverlap interval 1.5mm for 4-MSCT scan, kV of 120, and mA of 220. when theepigastrium was examed, Compound Diatrzoate Meglumlne solution(300ml) wasessential to turgor intestine half hour before examination and turgor stomach andduodenum before examination.All imaging was performed after theâ…£administration of 90-95 ml of nonioniciodinated contrast material, iohexol injected at a rate of 2.5 ml/sec using a powerinjector. Imaging was performed during the arterial and venous phase with a delay of22-26 sec and 70-80 sec.Imaging postprocessing: the data was passed into the postprocessing workstationto perform MPR(muitiplanar reformation). CTVL(CT virtual colon scopy), SSD(shaded surface display) and Ray sum were performed in case of 10 patientsgiven by gas enteroclysis.Two practised radiologists made the pre-operation diagnosis of qualitation andTNM staging according to clinical history and imaging. The results were comparedwith pathology.The TNM staging criteria of MSCT on large intestinal cancer:(1)T₀: no abnormality on MSCT. T₁: earlier stage, partly thickening ofintestine(＞5mm, =10mm), obvious enhancement, no obvious stenosis of intestinalcavity, T₂: thickening and contracion of intestine(＞10mm), clear of peripheryintestinal and fat, T₃: smoothless of outer margin, stenosis of intestinal cavity, slightlyunclear of periphery fat, T₄: density of periphery fat increases, linear high dendityextend to the outer fat.(2) No: no regional lymph node, N₁: single or less than 3 lymphnodes(1cm diameter) with high density and obvious enhancement in distance less than3cm to the lesion or intestinal wall, or several small lymph nodes(0.5cm diameter)with obvious enhancement, N₂: more than 3 lymph nodes with obvious enhancementin lesion, N₃: enlargement of lymph node around the root of mensentery vessels,obvious enhancement, (3) M₀: no metastasis, M₁: metastasis of liver and other organsin abdominal cavity.Assessment of lymph node: (1) solitary tubercle or fusing together, (2)obviousenhancement(circular).The criteria of pathologic staging: accoding to the standard made byInternational Union Against Cancer;UIAC in 1997:(1) T₀: no detected tumor, T₁:submucosa invaded, T₂: muscularis propria invaded, T₃: muscularis propria penetrated,T₄: plasma membrane penetrated or into abdominal cavity or directly invade otherorgans.(2) N₀: no regional lymph node metastasis, N₁: 1-3 lymph nodes metastasisaround large intestine, N₂: more than 4 lymph nodes metastasis around large intestine,N₃: many lymph nodes metastasis around blood vessel, (3) M₀: no metastasis, M₁:distant metastasis.Use SPSS13.0 to establish database and progress statistics analysis.Results:Predilection sites of large intestinal cancer are rectum and colon sigmoideum.Pathologic type is adenocarcinoma and moderately differentiated adenocarcinoma ismore often. Most of them are partly thickening of intestine and tumour, the intestine thick from 0.5 to 2.5cm, mean 1.4cm, size of tumour adenocarcinoma full of variety.It is common that 1/2 to 3/4 circumference become stenosis.CT value of the same patient with different CT period was analyzed by paringt-test and correlation analysis, coefficent ranged in 0.27-0.54, difference has statisticalsignificance((p＜0.05). CT value of the lesion in aterial period and venous periodincreased with the pumping of contrast and become more than 20Hu and 30Hu higherthan that in plain scan. In general, the lesion became enhanced unifomly withoutnecrosis and hemorrhage.Sensitivity of MSCT on detecting large intestinal cancer is 100%. Accurance ishigh. The accurate rate of T staging per-operation by 4-MSCT scan and 16-MSCTscan is 76.5% and 91.7% respectively, 84.7% for total 111 patients. The accurate rateis higher for T₃ than other staging, it is 88.9%, 97% and 94.2% for 4-MSCTscan,16-MSCT scan and total 111 patients. The data of T₂, T₃ and T_1-4 was analyzedby x² test, the result showed no statistical significance between T₂ and T₃staging(P＞0.05), while the accurate rate is higher for 16-MSCT than 4-MSCT in T_1-4staging, there is statistical significance(P＜0.05).Assessment of N staging by MSCT on large intestinal cancer is limited. Theaccurate rate of N staging pre-operationis 56.9%, 65% and 61.3% for 4-MSCT,16-MSCT and total patients, it is better to evaluate N₀ staging than any others. Theresults of 4-MSCT, 16 MSCT and total patients about N staging compared withpathology by means of signed rank sum test. P＜0.020. the difference has statisticalsignificance between CT scan and pathology no matter of 4-MSCT and 16-MSCT.The total data of 4-MSCT and 16-MSCT on N staging is analyzed by x² test. Theresults are x²=0.769, P=0.380, P＞0.05, which indicate no statistical significancebetween 4-MSCT and 16-MSCT on N staging.18 cases received examination of enteroscope and typical metastasis werereviewed, because these patients could not perform operation. Ten patiens had hapeticmetastasis, six patients had lymph nodes metastasis in pelvic cavity andretro-peritonium, one patient had lung metastasis, one patient has renal and duodenalmetastasis. It is sensitive to detect the metastasis both for 4-MSCT and 16-MSCT.MPR is one of the most common methods in imaging postprocessing with thebenefit of high sensitivity and direct-viewing, it can display the extension of the lesionin form of 2D reconstructive imaging. It is clearer and more delicate for 16-MSCT to reconstruct the image than 4-MSCT by more reconstructive data and thinner interval.Ten patients with large intestinal cancer were scanned by 4-MSCT with gasenterolysis. Nine of them succeeded to reconstruct the image. The advantage ofdifferent methods were summarized as below: CTVL can display the lesion in amulti-angle, 3D and dirct-viewing way and observe the distal intestine through thestenosis. SSD can show the stenosis clearly and present the entirety configuration.Ray sum equals to the lucidification management of SSD and is supplementary toSSD by means of determination of overlap lesions.Conclusion:1. It is sensitive for MSCT to detect the lesions in early, moderate and latestaging of large intestinal cancer.2. The accurate rate is high for MSCT to make assessment of T and M stagingpre-operation, it is limited to determinate the N staging.3. 16-MSCT is better to make T staging than 4-MSCT, but there is no statisticaldifference to assess N staging.4. Although 3D postprocessing can display the lesion in a multi-angle and overall way,it can not take place of transsection and MPR image to be the basic evidence.