Gastric carcinoma radiology ppt

Gastric carcinoma , staging , investigations , perfusion CT , CT staging.

1. Radiology of Ca Stomach and gastric lymphoma. Moderator : Dr Anupama C Consultant Radiologist. Presenter : Dr Sidharthan S Junior resident.

2. EPIDEMIOLOGY Environmental factors - highest incidences reported in Japan, Chile, Finland, Poland and Iceland. Dietary habits(diets rich in salted, smoked, or poorly preserved foods). Helicobacter pylori infection of the stomach (Major risk factor). Other predisposing conditions: include atrophic gastritis, pernicious anemia , gastric polyps, partial gastrectomy , Ménétrier’s disease, and hereditary factors.

3. ROUTES OF SPREAD Direct extension - invasion to liver, pancreas, and spleen. Lymphatic spread - involvement of local ( perigastric ) nodes and, subsequently, regional (celiac, hepatic, left gastric, and splenic ) or distant (left supraclavicular and left axillary ) nodes. Intraperitoneal seeding – Gastric CA may develop to malignant ascites , resultingintraperitoneal -seeded or omental metastases. Diffuse carcinomatosis - small bowel obstruction. Signet ring cell adenocarcinomas - bilateral “drop” metastases to the ovaries, known as Krukenberg tumors . Hematogenous metastases - liver is the most common site of hematogenous (as stomach is drained by portal vein) metastases from gastric carcinoma.

4. Radiological procedures for Gastric carcinoma Double contrast barium study UGI endoscopy Endoscopic ultrasound Computed tomography Perfusion CT MRI PET

5. RADIOGRAPHIC FINDINGS Early Gastric Cancer: The double-contrast upper GI examination has been widely recognized as the best radiologic technique for the diagnosis of early gastric cancer. Type I lesions are elevated lesions that protrude more than 5 mm into the lumen. Type II lesions are superficial lesions that are further subdivided into three groups—types IIa , IIb , and IIc depending on their morphologic features. Type IIa lesions are elevated but protrude less than 5 mm into the lumen. Type IIb lesions are essentially flat. Type IIc lesions are slightly depressed but do not penetrate beyond the muscularis mucosae . Type III lesions are true mucosal ulcerations, with the ulcer penetrating the muscularis mucosae but not the muscularis propria .

6. gastric carcinoma on abdominal radiographs B. In another patient, the gas-filled stomach has a narrowed, tubular appearance ( arrow) caused by a scirrhous carcinoma ( linitis plastica ). A. Close-up view from an abdominal radiograph shows a soft tissue mass ( arrows) indenting the lesser curvature of the gas-filled stomach.

7. Appearance of the Stomach in DC barium studies B. Rugal fold on posterior wall of gastric body is depicted as tubular, slightly undulating, radiolucent filling defect (black arrowheads) in shallow barium pool. Dense barium pool outlines contour (white arrowheads) of gastric fundus (F). C. Shows normal areae gastricae pattern in antrum as 2–3-mm polygonally shaped radiolucent tufts of mucosa outlined by barium in grooves. Areae gastricae are slightly larger in distal gastric body than in antrum . A. Shows normal gastric cardia with smooth folds radiating to central point at closed gastroesophageal junction, also known as cardiac rosette. Black arrows denote normal extrinsic impression by adjacent spleen.

8. Gastric cancer – anterior or posterior wall in barium study?? Dependent or posterior wall Filling defects in the barium pool Nondependent or anterior wall Etched in white by a thin layer of barium trapped between the edge of the mass and adjacent mucosa.

9. Early gastric cancers A. A type I lesion is seen as a polypoid mass ( arrow) on the greater curvature of the gastric body. B. A type IIa lesion is manifested by a focal cluster of shallow elevations and nodules ( arrows) in the gastric body. C. A type IIc lesion is manifested by shallow, irregular areas of ulceration and nodularity ( arrows) in the gastric antrum . D. A type III lesion is seen as a scalloped, irregular antral ulcer with nodular, clubbed folds surrounding the ulcer crater.

10. Malignant gastric ulcer Malignant ulcer ( arrow) is seen on the lesser curvature of the antrum . This ulcer has an intraluminal location. Also note how the folds converging to the ulcer have a nodular, clubbed appearance because of infiltration by tumor . Ulcerated mass on the greater curvature of the antrum . Again, note how the ulcer ( white arrow) has an intraluminal location. Also note how the mass itself is etched in white ( black arrows).

11. Localized scirrhous carcinoma A short, annular lesion is seen in the prepyloric region of the antrum . Note how the lesion has an abrupt, shelflike proximal border. Irregular narrowing is seen in the gastric fundus and body with sparing of the antrum . ANTRUM PROXIMAL STOMACH

12. Scirrhous carcinomas of the stomach There is marked narrowing of the antrum caused by infiltration of the wall by tumor . In another patient, there is encasement of the entire stomach by a scirrhous tumor , producing a diffuse linitis plastica appearance.

13. Calcified scirrhous carcinoma A. Abdominal radiograph shows a large cluster of punctate or sand-like calcifications in the region of the stomach. B. Barium study in the same patient reveals marked antral narrowing . C. CT scan shows lobulated thickening of the gastric wall with extensive calcification in another patient.

14. Infiltrating gastric carcinomas A. Irregular narrowing and ulceration are seen in the antrum because of an advanced, infiltrating carcinoma. B. an infiltrating carcinoma of the proximal stomach causes marked narrowing and spiculation of the upper gastric body.

15. Carcinoma of the cardia The normal anatomic landmarks at the cardia have been obliterated and replaced by a plaquelike lesion ( straight arrows) containing a shallow area of ulceration ( curved arrow). The cardiac rosette has been replaced by a relatively flat mass with a central ulcer. The tumor extends into the distal esophagus . There is diffuse nodularity in the fundus with obliteration of the normal cardiac landmarks. Also note involvement of the distal esophagus .

16. Secondary achalasia Secondary achalasia caused by gastric carcinoma. (mostly due to submucosal spread) There is smooth, tapered narrowing of the distal esophagus , producing the classic beaklike appearance of achalasia . B. A radiograph of the stomach reveals an advanced scirrhous carcinoma of the gastric fundus that has invaded the distal esophagus .

17. COMPUTED TOMOGRAPHIC FINDINGS Requires optimal gastric distention - neutral (water-attenuation) contrast agent / oral effervescent agent. Optimal MDCT detection of gastric cancer requires that imaging data be collected with the thinnest possible detector configuration (0.6-0.75 mm). Overlapping reconstructions enable the creation of 3D data sets with near-isotropic voxels . Display images are created at 3- to 4-mm intervals and are transmitted directly to PACS. Clinically useful 3D images displaying the gastric tumor and extragastric extension can be created and selected for the patient’s electronic imaging database. Intravenous administration of iodinated contrast material is critical, not only for assessing the primary tumor but also for local staging and detection of distant metastases.

18. MDCT of gastric carcinoma correlated with Borrmann classification A- Type I polypoid neoplasm. B- Type II fungating neoplasm C- Type III ulcerated neoplasm D- Type IV infiltrating neoplasm

19. MDCT to predict the histology of the tumor ?? Can MDCT be used to predict histological variants - ? NO . * However calcification and/or areas of low attenuation within a thickened gastric wall should suggest the presence of a mucinous carcinoma.

20. Perfusion CT in Gastric Ca Perfusion CT (P-CT) allows measurement of physiologic parameters associated with tumor perfusion and is an established marker of angiogenesis. The main hemodynamic parameter assessed is the tumor blood flow . Preliminary studies with P-CT of Gastric Ca have shown that blood volume was significantly increased in Gastric Ca and there was no difference between Gastric Ca with and without lymph node metastases. Another study by Yao et al .  showed that a decreased blood flow value may reflect a progressive state of Gastric Ca. P-CT can assess the malignancy grade of Gastric Ca non-invasively. P-CT-derived blood volume correlated significantly with microvessel density of the tumor , which may be valuable information during preoperative assessment with potential for targeted therapies .

21. MRI in Gastric Ca MRI is promising for T staging of GC as individual layers may be better differentiated compared with CT. MRI is performed with gastric distension using water or effervescent granules . The detection rates of gastric tumors were similar for MRI and MDCT (92 %). Currently, the use of MRI for staging of GC is limited to special circumstances when patients are allergic to iodinated contrast media, there is concern about radiation exposure with CT or invasiveness of EUS, or as a problem-solving tool when both CT and EUS are inconclusive.

22. PET in Gastric Ca PET (FDG) with CT has been recognized as a useful diagnostic technique in clinical oncology and several studies for assessing the accuracy for nodal and metastatic staging in Gastric Ca. PET has low sensitivity for the primary tumor and lymph node metastases, therefore is limited in the preoperative work-up and best used as part of a comprehensive work-up . The major advantage of FDG-PET/CT is in the detection of distant metastases to the liver, lungs, and skeleton . However, small peritoneal nodules may be missed due to the low resolution of FDG-PET/CT, and MDCT remains the most widely used technique for the detection of peritoneal metastases.

23. Approach for imaging Mass is suspected at the gastroesophageal junction Repeat scanning with oral effervescent agent in the prone or left-side down decubitus position index of suspicion for malignant tumor ?? YES NO Endoscopic ultrasound (EUS) Double-contrast and biopsy. barium study Approach of radiological imaging for a suspected malignant gastric tumour Contrast enhanced MDCT : IV iodinated contrast at 3ml/s. Enhancing pattern : Bright enhancement - mucosal and serosal layers and Less enhancement - submucosal and muscular layers.

24. Gastric carcinoma with stratified enhancement patterns on MDCT. Contrast-enhanced MDCT scan shows a malignant posterior wall ulcer with irregular margins. Note: decreased enhancement of the adjacent mucosa and a relatively hypodense submucosa . B,C. Contrast-enhanced MDCT scans through the proximal stomach in a 35-year-old man show an irregularly thickened gastric wall extending to the gastroesophageal junction secondary to a primary scirrhous carcinoma with linitis plastica .

25. Why gastric distension is essential for imaging ?? Inadequate gaseous distention mimicking a fundal tumor . A. Doublecontrast radiograph of the stomach shows a possible infiltrating lesion ( arrows) on the posterior wall of the fundus . B. After administration of additional effervescent agent, there is better distention of the fundus , eliminating the possibility of tumor . Note: how the normal cardiac rosette is now visible.

26. Lymph node metastasis Perigastric lymph node metastases from gastric carcinoma. Ulcerative gastric carcinoma with perigastric lymphnodes . Post gastrectomy (for gastric carcinoma) with peripancreatic lymphnodes .

27. TNM Staging classification

28. Staging Computed Tomography, Endoscopic Ultrasonography , Magnetic Resonance Imaging (MRI), and Positron Emission Tomography (PET/CT).

29. Staging - Computed Tomography To assess disease spread beyond the gastric wall, Intraperitoneal seeding and Blood-borne metastases. T-stage accuracy improved from 77% on axial images to 84% on volumetric images. the accuracy of MDCT for serosal invasion was 93%. (So, MDCT is more useful for advacned cases.) MDCT enabled detection of 96% of advanced gastric cancers and 41% of early gastric cancers, with an overall T-stage accuracy of 85%. CT gastroscopy : By using an effervescent agent to maximize gastric distention and create a 3D volume-rendered “luminal cast” with multiplanar reformatted images and IV contrast enhancement, other investigators have been able to achieve high accuracy in differentiating T1a from T1b tumors .

30. Computed Tomography CT is limited by its inability to identify lymphatic metastases in lymph nodes that are not enlarged. The detection of such metastases could potentially be improved by using monoenergetic , low- keV images derived from dual-energy CT acquisitions. In patients with advanced gastric carcinoma, peritoneal carcinomatosis may be manifested on MDCT by characteristic findings, Including soft tissue masses and nodules in peritoneal reflections, Retraction of the mesenteric root, Omental caking, and Loculated ascites . However detection of intraperitoneal metastases by MDCT remains poor. In one study, 18-FDG-PET/ CT was found to have an even lower sensitivity than MDCT for detecting these intraperitoneal implants.

31. Pathologic T stages and MDCT criteria for T stages of Gastric Ca Pathologic T stage MDCT criteria pT1: tumor invades the lamina propria , muscularis mucosae or submucosa . T1 : strong enhancement with focal thickening in the inner and/or middle layer, but the outer layer shows no enhancement; enhancement of the stomach wall only but the wall is not thickened; wall thickening with intense enhancement of the inner layer and the presence of a hypodense stripe/layer. pT2: tumor invasion into the muscularis propria . T2–3 : the entire stomach wall thickness is thickened to variable extent but there is a regular surface of outer layer pT3: tumor invades subserosa . of gastric wall; normal appearance of perigastric fat. pT4a: tumor perforates the serosa . T4a: the entire stomach wall is thickened with homogeneous or inhomogeneous enhancement ; irregular surface of the outer layer of the gastric wall ; presence of micronodules or dense stranding in the perigastric fat pT4b: tumor invades adjacent structures. T4b: There is extension of the tumor into adjacent contiguous organs in addition to wall thickening

32. Endoscopic Ultrasonography The introduction and dissemination of EUS has substantially improved the accuracy of local staging for gastric cancer. A major advantage of EUS is its ability to visualize the various layers of the gastric wall, perigastric lymph nodes, and relationship of the tumor to the surrounding tissues, enabling determination of the depth of wall invasion and extent of regional lymph node involvement by tumor . EUS is best performed as a complementary test to cross-sectional imaging studies such as CT for local tumor staging. Technique: Frequency range of 5 to 12 MHz, Clinical resolution of 200 μm .

33. Endoscopic Ultrasonography There are two basic types of endosonographic equipment available for clinical use— a dedicated EUS endoscope with maneuvering and biopsy capabilities and a standard endoscope in which the EUS equipment is fitted onto catheters and passed through the endoscope. EUS requires a trained examiner and is therefore operator dependent. The examination is usually performed under conscious sedation in an outpatient setting. Dedicated echo-endoscopes have a suction capability, so air can be removed from the stomach and deaerated water instilled to allow for better acoustic coupling. An inflatable balloon surrounds the transducer and is filled with deaerated water to increase the surface contact area and improve the imaging window.

34. LAYER REPRESENTS first hyperechoic layer balloon-mucosal interface second hypoechoic layer deep mucosa third hyperechoic layer Submucosa fourth hypoechoic layer muscularis propria fifth hyperechoic layer subserosa and serosa Endoscopic Ultrasonography With standard technique, EUS visualizes the stomach as a five-layered structure; each individual layer corresponds to a histologically defined layer of the gastric wall .

35. Endoscopic Ultrasonography EUS is performed from the transgastric position, allowing visualization of the gastric wall, adjacent lymph nodes, and nearby organs, including the pancreas, spleen, left kidney, and, to a limited degree, the liver. EUS is limited by its inability to assess for metastases in the right lobe of the liver or more remote sites because of a limited depth of penetration and imaging window. EUS the examination can be combined with a standard upper endoscopy for biopsy specimens of the primary tumor . LIMITATIONS: As on CT, it may be difficult on EUS to differentiate neoplastic involvement of the stomach from inflammatory processes or fibrosis. T classification of gastric cancer because differentiation of subserosal (T2) from serosal (T3) invasion can be extremely difficult.

36. Endoscopic Ultrasonography EUS has been shown to be a highly accurate technique for assessing the depth of tumor invasion and presence or absence of regional lymph node involvement in patients with gastric carcinoma. the overall accuracy of EUS for T staging has ranged from 85% to 88%. The finding of a thickened muscularis propria is almost pathognomonic of a malignant gastric tumor , usually gastric carcinoma. EUS is also the most sensitivity imaging technique for detecting perigastric lymph nodes. The overall diagnostic accuracy of EUS for determining nodal status (N classification) has ranged from 70% to 90%.

37. Endoscopic Ultrasound Grading

38. Other investigations for staging Diffusion weighted imaging (DWI) has been shown to be comparable to MDCT for local staging but is more sensitive than MDCT for detecting lymph node metastases. 18-FDG-PET/CT is also a useful test for whole-body imaging of distant metastases from gastric cancer and for detecting recurrent tumor after treatment. However, 18-FDG-PET/CT has been shown to be inferior to MDCT and diffusion-weighted MRI for detecting regional lymph node metastases.

39. Barium vs PET CT vs MDCT vs DW-MRI

40. Gastric lymphoma Lymphoma involves the stomach more frequently than any other portion of the gastrointestinal tract. PRIMARY GASTRIC LYMPHOMA- Confined to stomach and regional lymphnodes . SECONDARY GASTRIC LYMPHOMA- generalised lymphoma with gastric involvement. The vast majority of gastric lymphomas are non-Hodgkin’s lymphomas of B-cell origin.(mostly arise from mucosa-associated lymphoid tissue (MALT) in patients with chronic H-pylori gastritis.) Low grade lymphoma (AKA- Pseudolymphoma ) (untreated)  High grade lymphoma. [But now, monoclonal B-cell proliferations or true B-cell MALT is Pseudolymphoma ]. Difficult to differentiate from gastric carcinoma on radiologic or endoscopic examination.

41. Various forms of gastric lymphoma

42. Development & staging of Gastric lymphoma Chronic H. pylori gastritis leads to the acquisition of lymphoid follicles and aggregates in the lamina propria (MALT) and the subsequent development of low-grade, B-cell MALT lymphomas. ANN ARBOR STAGING STAGE INVOLVEMENT stage IE lesions involve the gastric wall stage IIE lesions involve regional lymph nodes in the abdomen stage III lesions lymph nodes above and below the diaphragm stage IV lesions widely disseminated lymphomas

43. Gastric lymphoma on CT Marked thickening of the gastric wall with homogeneous enhancement caused by the infiltrative form of gastric lymphoma. A large ulcer crater is present within a soft tissue mass in the stomach.

44. ENDOSCOPIC FINDINGS Low-grade gastric MALT lymphomas shallow ulcers, polypoid lesions, or erythematous , nodular mucosa high-grade gastric MALT lymphomas enlarged rugal folds, infiltrative masses, nodular, polypoid or ulcerated lesions in the stomach. Gastric lymphomas may be difficult to differentiate from other malignant lesions bassed on endoscopic findings.

45. Approach to gastric lymphoma!! Define the lesion in Barium study. Uniform sharply marginated Thickened area gastricae Multiple , confluent, rounded nodules H-Pylori Gastritis Poorly defined confluent nodules with central umblications Low grade MALToma Solitary lesion in stomach GIST Bull eye’s lesions – DD – Lyphoma , Kaposi sarcoma , metastasis , carcinoid tumor .

46. Response of gastric lymphoma to chemotherapy    6 months- Cavitation CHEMOTHERAPHY 1 year Before treatment

47. Refrences Marc S. Levine Alec J. Megibow Michael L. Kochman;Textbook of gastrointestinal radiology. 2015;sec 5;546-569. Kikuchi S, Hiki Y, Shimao H, Sakakibara Y, Kakita A. Tumor volume: a novel prognostic factor in patients who undergo curative resection for gastric cancer.  Langenbecks Arch Surg. 2000;385:225–228. K ikuchi S, Sakuramoto S, Kobayashi N, et al. A new staging system based on tumor volume in gastric cancer. Anticancer Res. 2001;21:2933–2936. PMid:11712789 . Cuenod CA, Fournier L, Balvay D, Guinebretière JM. Tumor angiogenesis: pathophysiology and implications for contrast-enhanced MRI and CT assessment.  Abdom Imaging.  2006;31:188–193. Lee TY, Purdie TG, Stewart E. CT imaging of angiogenesis. Q J Nucl Med. 2003;47:171–187.PMid:12897709 . Yao J, Yang ZG, Chen TW, Li Y, Yang L. Perfusion changes in gastric adenocarcinoma : evaluation with 64-section MDCT.  Abdom Imaging. 2010;35:195–202.  Satoh A, Shuto K, Okazumi S, et al. Role of perfusion CT in assessing tumor blood flow and malignancy level of gastric cancer. Dig Surg. 2010;27:253–260.  Yao J, Yang ZG, Chen HJ, Chen TW, Huang J. Gastric adenocarcinoma : can perfusion CT help to noninvasively evaluate tumor angiogenesis?  Abdom Imaging. 2011;36:15–21. 

48. Thank you…