胃腸道常見疾病的影像診斷

1、First Affiliated Hospital of FMU,胃腸道檢查前準備,因檢查部位不同準備各異胃：口服清水800-1000 mL,必要時于檢查前10分鐘肌注654-2 20 mg小腸：分次口服2.5% 甘露醇 1200 mL，1小時內(nèi)服完，檢查前10分鐘肌注654-2 20 mg,First Affiliated Hospital of FMU,掃描主要參數(shù),層厚5mm, 薄層2mm行MPR重建需調(diào)整窗寬（ww

2、350)、窗位（10）增強檢查掃描時間： 建議注射造影劑后38S 左右開始掃描，90S獲取靜脈期圖像,First Affiliated Hospital of FMU,胃部腫瘤,First Affiliated Hospital of FMU,胃 癌,胃淋巴瘤,胃部腫瘤,,惡性腫瘤,,良性腫瘤,胃腸間質(zhì)瘤,,First Affiliated Hospital of FMU,胃 癌,First Affiliated Hos

3、pital of FMU,背 景,起源于胃粘膜上皮胃竇、小彎及賁門多見,First Affiliated Hospital of FMU,分 期,Ⅰ 限于腔內(nèi)的腫塊，無胃壁增厚，無鄰近或遠處擴散Ⅱ 胃壁增厚>1.0cm，但癌未超出胃壁Ⅲ 胃壁增厚，并直接侵及鄰近器官，但無遠處轉(zhuǎn)移Ⅳ 遠處轉(zhuǎn)移,First Affiliated Hospital of FMU,主要的CT征象,胃壁增厚軟組織腫塊形成胃周脂肪密度增高

4、胃周或/和腹膜后淋巴結腫大（>5mm)鄰近器官侵犯遠處轉(zhuǎn)移,First Affiliated Hospital of FMU,,,First Affiliated Hospital of FMU,,First Affiliated Hospital of FMU,,胃癌累及漿膜外脂肪,First Affiliated Hospital of FMU,胃癌累及漿膜外脂肪,First Affiliated Hospital of

5、 FMU,胃竇部粘膜內(nèi)腺癌,,First Affiliated Hospital of FMU,胃癌并腹膜轉(zhuǎn)移,,First Affiliated Hospital of FMU,,First Affiliated Hospital of FMU,胃淋巴瘤,First Affiliated Hospital of FMU,背 景,淋巴瘤定義 :淋巴瘤(lymphoma)起源于淋巴結和淋 巴組織,其發(fā)生大多與免疫應答過程中淋巴細胞增殖分

6、化產(chǎn)生的某種免疫細胞惡變有關,是免疫系統(tǒng)的惡性腫瘤.病因:淋巴瘤的病因和發(fā)病機制不完全清楚，可能與病毒感染有關。,First Affiliated Hospital of FMU,淋巴瘤的分類,霍奇金淋巴瘤（Hodgkin lymphoma, HL):約占所有淋巴瘤的10%-20%.其90%的病例原發(fā)于淋巴結，病變往往從一個或一組淋巴結開始，逐漸由近及遠地向附近的淋巴結擴散。非霍奇金淋巴瘤（ non Hodgkin lymphoma

7、, NHL):約占所有淋巴瘤的80%-90%,其中2/3原發(fā)于淋巴結，1/3原發(fā)于淋巴結外器官或組織。,First Affiliated Hospital of FMU,臨床特點,淋巴瘤可發(fā)生于身體的任何部位；其中淋巴腫大和局部腫塊是其特征性的臨床表現(xiàn)，同時可有相應器官壓迫的癥狀。患者常有發(fā)熱、消瘦、盜汗等全身癥狀，最后出現(xiàn)惡病質(zhì)。,First Affiliated Hospital of FMU,胃腸道淋巴瘤特點,起源于胃腸道粘膜固

8、有層和粘膜下層的淋巴組織,常在粘膜固有層或粘膜下層沿器官長軸生長,再向腔內(nèi)、腔外侵犯.約占結外淋巴瘤30％，其中，胃淋巴瘤占50％左右.按其細胞組成可分為霍奇金淋巴瘤和非霍奇金淋巴瘤，其中非霍奇金淋巴瘤占大多數(shù)，霍奇金淋巴瘤罕見.胃腸道非霍奇金淋巴瘤大多數(shù)來自B 淋巴細胞，小部分腸道淋巴瘤起源于T 淋巴細胞，極少數(shù)來自組織細胞或其他網(wǎng)狀細胞.,First Affiliated Hospital of FMU,原發(fā)性胃淋巴瘤的CT表現(xiàn)

9、,以胃壁增厚為主要特征，具備以下特點： 1. 可多器官同時累及 2. 病變范圍廣且胃壁增厚明顯 3. 病變段胃壁有一定擴張性和柔軟度，梗阻征象 較少見 4. 病灶密度相對較均勻，內(nèi)部很少壞死或壞死灶 較小 5. 增強掃描呈輕至中度強化 6. 病變周圍脂肪間隙大多清晰，向周圍侵犯較少 7. 腹腔或腹膜后淋巴結腫大多見,First Affilia

10、ted Hospital of FMU,彌漫性胃粘膜相關性B細胞淋巴瘤,,,First Affiliated Hospital of FMU,非霍奇金大B細胞淋巴瘤,,First Affiliated Hospital of FMU,胃間質(zhì)瘤,First Affiliated Hospital of FMU,胃間質(zhì)瘤,Express the KIT protein (CD117, stem cell factor receptor)D

11、efined as spindle cell, epithelioid, or pleomorphic mesenchymal tumors 腫塊常較局限,惡性者常較大，可向腔內(nèi)或腔外生長，壞死多見，增強掃描病灶呈明顯強化,常無腹腔淋巴結腫大。,First Affiliated Hospital of FMU,胃間質(zhì)瘤,,First Affiliated Hospital of FMU,,胃間質(zhì)瘤并壞死,,First Affiliat

12、ed Hospital of FMU,,First Affiliated Hospital of FMU,高危險性間質(zhì)瘤,First Affiliated Hospital of FMU,(胃竇部）胃腸間質(zhì)瘤（高度危險性）,First Affiliated Hospital of FMU,間質(zhì)瘤伴壞死 （高度危險）,First Affiliated Hospital of FMU,腸道常見病變,First Affiliated Hosp

13、ital of FMU,間質(zhì)瘤,一般病灶大，血供豐富，易囊變或壞死，明顯強化，附近腸壁無明顯增厚，一般腸系膜根部和臨近無明顯淋巴結腫大。,First Affiliated Hospital of FMU,回腸末段間質(zhì)瘤,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,原發(fā)性腸淋巴瘤的CT表現(xiàn),病灶沿腸壁血管長軸浸潤性生長，受累的腸段一般較長，腸腔狹窄程度

14、較輕，大多數(shù)病變腸管形態(tài)可變，具備以下特點: 1.腸壁的節(jié)段性或彌漫性增厚，腸腔內(nèi)或腸腔內(nèi)外的軟組織腫塊等. 2.病灶可單發(fā)或多發(fā)，少數(shù)甚至累及整段小腸或大腸. 3.多數(shù)病灶與周圍組織分界清晰，瘤灶多表現(xiàn)為輕度或中度強化. 4.部分淋巴瘤伴腸系膜及腹膜后淋巴結受累。 5.腸道淋巴瘤CT特征性征象為腸腔“動脈瘤樣擴張”，其病理基礎為腫瘤浸潤、破壞腸壁內(nèi)神經(jīng)所致，但出現(xiàn)率并不高.,First Affiliated Hos

15、pital of FMU,末段回腸淋巴瘤,右下腹末段回腸管壁明顯增厚 ,密度尚均勻,邊界清晰.,First Affiliated Hospital of FMU,,,First Affiliated Hospital of FMU,腸系膜旁見多發(fā)腫大淋巴結,,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,First Affiliated Hospita

16、l of FMU,橫結腸淋巴瘤,First Affiliated Hospital of FMU,結腸癌,腸壁增厚、形成腫塊,病灶較為局限,常伴有腸腔的向心性狹窄及腸梗阻表現(xiàn), 強化較明顯,病灶較大時易伴有缺血壞死區(qū),常侵犯周圍組織,可有淋巴轉(zhuǎn)移等.,First Affiliated Hospital of FMU,右半結腸癌,First Affiliated Hospital of FMU,腸結核,結核：腸結核在臨床上有“結核中毒”癥

17、狀，病灶邊界不清，病變腸管縮小，變形、僵直，伴相鄰腹膜強化，淋巴結通常表現(xiàn)為周邊強化，伴中央的干酪性壞死，通常不融合。,First Affiliated Hospital of FMU,右半結腸結核,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,Crohn病,一般僅發(fā)生在小腸，表現(xiàn)為腸壁全層較均勻、規(guī)則的增厚，增厚的程度較輕，病變呈多節(jié)段、跳躍式分布，