胃肠道常见疾病的影像诊断.ppt

1、First Affiliated Hospital of FMU,胃肠道检查前准备,因检查部位不同准备各异胃：口服清水800-1000 mL,必要时于检查前10分钟肌注654-2 20 mg小肠：分次口服2.5% 甘露醇 1200 mL，1小时内服完，检查前10分钟肌注654-2 20 mg,First Affiliated Hospital of FMU,扫描主要参数,层厚5mm, 薄层2mm行MPR重建需调整窗宽（ww 350)、窗位（10）增强检查扫描时间： 建议注射造影剂后38S 左右开始扫描，90S获取静脉期图像,First Affiliated Hospital of FMU,胃部

2、肿瘤,First Affiliated Hospital of FMU,胃 癌,胃淋巴瘤,胃部肿瘤,恶性肿瘤,良性肿瘤,胃肠间质瘤,First Affiliated Hospital of FMU,胃 癌,First Affiliated Hospital of FMU,背 景,起源于胃粘膜上皮胃窦、小弯及贲门多见,First Affiliated Hospital of FMU,分 期, 限于腔内的肿块，无胃壁增厚，无邻近或远处扩散 胃壁增厚1.0cm，但癌未超出胃壁 胃壁增厚，并直接侵及邻近器官，但无远处转移 远处转移,First Affiliated Hospital of FMU,主要

3、的CT征象,胃壁增厚软组织肿块形成胃周脂肪密度增高胃周或/和腹膜后淋巴结肿大（5mm)邻近器官侵犯远处转移,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,胃癌累及浆膜外脂肪,First Affiliated Hospital of FMU,胃癌累及浆膜外脂肪,First Affiliated Hospital of FMU,胃窦部粘膜内腺癌,First Affiliated Hospital of FMU,胃癌并腹膜转移,First Affil

4、iated Hospital of FMU,First Affiliated Hospital of FMU,胃淋巴瘤,First Affiliated Hospital of FMU,背 景,淋巴瘤定义 :淋巴瘤(lymphoma)起源于淋巴结和淋 巴组织,其发生大多与免疫应答过程中淋巴细胞增殖分化产生的某种免疫细胞恶变有关,是免疫系统的恶性肿瘤.病因:淋巴瘤的病因和发病机制不完全清楚，可能与病毒感染有关。,First Affiliated Hospital of FMU,淋巴瘤的分类,霍奇金淋巴瘤（Hodgkin lymphoma, HL):约占所有淋巴瘤的10%-20%.其90%的病例原

5、发于淋巴结，病变往往从一个或一组淋巴结开始，逐渐由近及远地向附近的淋巴结扩散。非霍奇金淋巴瘤（ non Hodgkin lymphoma, NHL):约占所有淋巴瘤的80%-90%,其中2/3原发于淋巴结，1/3原发于淋巴结外器官或组织。,First Affiliated Hospital of FMU,临床特点,淋巴瘤可发生于身体的任何部位；其中淋巴肿大和局部肿块是其特征性的临床表现，同时可有相应器官压迫的症状。患者常有发热、消瘦、盗汗等全身症状，最后出现恶病质。,First Affiliated Hospital of FMU,胃肠道淋巴瘤特点,起源于胃肠道粘膜固有层和粘膜下层的淋巴组织,

6、常在粘膜固有层或粘膜下层沿器官长轴生长,再向腔内、腔外侵犯.约占结外淋巴瘤30，其中，胃淋巴瘤占50左右.按其细胞组成可分为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数，霍奇金淋巴瘤罕见.胃肠道非霍奇金淋巴瘤大多数来自B 淋巴细胞，小部分肠道淋巴瘤起源于T 淋巴细胞，极少数来自组织细胞或其他网状细胞.,First Affiliated Hospital of FMU,原发性胃淋巴瘤的CT表现,以胃壁增厚为主要特征，具备以下特点： 1. 可多器官同时累及 2. 病变范围广且胃壁增厚明显 3. 病变段胃壁有一定扩张性和柔软度，梗阻征象 较少见 4. 病灶密度相对较均匀，内部很少坏死或坏

7、死灶 较小 5. 增强扫描呈轻至中度强化 6. 病变周围脂肪间隙大多清晰，向周围侵犯较少 7. 腹腔或腹膜后淋巴结肿大多见,First Affiliated Hospital of FMU,弥漫性胃粘膜相关性B细胞淋巴瘤,First Affiliated Hospital of FMU,非霍奇金大B细胞淋巴瘤,First Affiliated Hospital of FMU,胃间质瘤,First Affiliated Hospital of FMU,胃间质瘤,Express the KIT protein (CD117, stem cell factor receptor)Defined as

8、 spindle cell, epithelioid, or pleomorphic mesenchymal tumors 肿块常较局限,恶性者常较大，可向腔内或腔外生长，坏死多见，增强扫描病灶呈明显强化,常无腹腔淋巴结肿大。,First Affiliated Hospital of FMU,胃间质瘤,First Affiliated Hospital of FMU,胃间质瘤并坏死,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,高危险性间质瘤,First Affiliated Hospital of FMU,

9、(胃窦部）胃肠间质瘤（高度危险性）,First Affiliated Hospital of FMU,间质瘤伴坏死 （高度危险）,First Affiliated Hospital of FMU,肠道常见病变,First Affiliated Hospital of FMU,间质瘤,一般病灶大，血供丰富，易囊变或坏死，明显强化，附近肠壁无明显增厚，一般肠系膜根部和临近无明显淋巴结肿大。,First Affiliated Hospital of FMU,回肠末段间质瘤,First Affiliated Hospital of FMU,First Affiliated Hospital of FM

10、U,原发性肠淋巴瘤的CT表现,病灶沿肠壁血管长轴浸润性生长，受累的肠段一般较长，肠腔狭窄程度较轻，大多数病变肠管形态可变，具备以下特点: 1.肠壁的节段性或弥漫性增厚，肠腔内或肠腔内外的软组织肿块等. 2.病灶可单发或多发，少数甚至累及整段小肠或大肠. 3.多数病灶与周围组织分界清晰，瘤灶多表现为轻度或中度强化. 4.部分淋巴瘤伴肠系膜及腹膜后淋巴结受累。 5.肠道淋巴瘤CT特征性征象为肠腔“动脉瘤样扩张”，其病理基础为肿瘤浸润、破坏肠壁内神经所致，但出现率并不高.,First Affiliated Hospital of FMU,末段回肠淋巴瘤,右下腹末段回肠管壁明显增厚 ,密度尚均匀,边界

11、清晰.,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,肠系膜旁见多发肿大淋巴结,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,横结肠淋巴瘤,First Affiliated Hospital of FMU,结肠癌,肠壁增厚、形成肿块,病灶较为局限,常伴有肠腔的向心性狭窄及肠梗阻表现, 强化较明显,病灶较大时易伴有缺血坏死区,常侵犯周围组织,可有淋巴转移等.,F

12、irst Affiliated Hospital of FMU,右半结肠癌,First Affiliated Hospital of FMU,肠结核,结核：肠结核在临床上有“结核中毒”症状，病灶边界不清，病变肠管缩小，变形、僵直，伴相邻腹膜强化，淋巴结通常表现为周边强化，伴中央的干酪性坏死，通常不融合。,First Affiliated Hospital of FMU,右半结肠结核,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,Crohn病,一般仅发生在小肠，表现为肠壁全层较均匀、规则的增厚，增厚的程度较轻，病变呈多节段、跳跃式分布，范围较广泛，引起的肠系膜周围淋巴结增生一般也比较少，活动期病变肠壁强化明显。,First Affiliated Hospital of FMU,Crohns病,First Affiliated Hospital of FMU,First Affiliated Hospital of FMU,Thanks for your attention !,