1. Department of Radiology. Seoul St. Mary's Hospital The Catholic University of Korea Yu Ri Shin, Seung Eun Jung, Sung Eun Rha, Soon Nam Oh, Yoo Sung Kim, Jae Young Byun Various gastroduodenal submucosal lesions: EUS and MDCT correlation

2. Background Both Endoscopic ultrasound (EUS) and Multidetector computed tomography (MDCT) are two main modalities for evaluating various gastroduodenal submucosal lesions EUS has an advantage in evaluating the layer of the origin of tumors and their internal architecture owing to its high spatial resolution MDCT, on the other hand, is advantageous in tumor characterization with the use of contrast enhancement, and evaluating extragastric lesions

3. Purpose To present the findings from EUS and MDCT of various gastroduodenal submucosal lesions, to compare characteristic EUS findings with MDCT, and to specify advantage of each modalities

4. Materials and Methods We retrospectively reviewed the medical records and imaging (EUS and MDCT) of 400 patients with pathologic findings. The lesions include gastrointestinal stromal tumor, leiomyoma, carcinoid, ectopic pancreas, vascular structures, glomus tumor, neurogenic tumor, gastritis cystic profunda and hemangioma in the left lobe of the liver.

5. Business order Business order EUS findings of various gastroduodenal submucosal lesionsEUS findings of various gastroduodenal submucosal lesions Comparison of EUS and MDCT Superiority of each modalities to correct diagnosis

6. Normal five layers of gastric wall on EUS Five layers Five layers - Hyperechoic superficial mucosa or inner interface - Hypoechoic deep mucosa (arrows) - Hyperechoic submucosa - Hypoechoic muscularis propria (arrowhead) - Hyperechoic serosa or outer interface

7. Submucosal mesencymal tumor GIST EUS show (A) a homogeneous hypoechoic mass arising from the submucosal layer of gastric body, and (B) a solid mass of mixed echogenicity with nodular margin in gastric body. The masses were confirmed low risk and high risk gastrointestinal stromal tumor, respectively. BA

8. Submucosal mesencymal tumor (A) Leiomyoma is shown as heterogeneous hypoechoic mass arising muscularis proper in gastric fundus. (B) Lipoma is shown as homogeneous isoechoic mass in the submucosal layer. Endoscopic resection confirmed the diagnosis. BA

9. Vascular tumor (A,B) Glomus tumors from two distinct individuals are shown as solid mass of mixed echogenicity arising submucosal layer in gastric antrum. Although dense homogeneous enhancement of a solitary submucosal tumor on CECT is a nonspecific finding, it can be more helpful.(C) Lymphangioma is shown as anechoic lesion in the submucosal layer. Endoscopic resection confirmed the diagnosis. AB C

10. Non-tumorous submucosal lesions (A,B) Gastritis cystica profunda is shown as ill-defined hyperechoic submucosal mass with internal cysts. It corresponds to the proliferation and cystic alteration of the pseudopyloric glands, which is characteristic of gastritis cystica profunda. (C) Ectopic pancreas is shown as a solid mass of mixed echogenicity that arising submucosal layer and disrupting the gastric wall layers. AB C

11. Business order Business order EUS findings of various gastroduodenal lesionsEUS findings of various gastroduodenal lesions Comparison of EUS and MDCT Superiority of each modalities to correct diagnosis

12. Ectopic pancreas (A) EUS shows a well defined hypoechoic mass in the submucosal layer of antrum, and (B) the corresponding lesion is demonstrated on axial CT image as a small polypoid lesion with highly enhancing mucosal layer (arrow). CT findings of ectopic pancreas in the stomach is nonspecific for the diagnosis, except for its location. The degree of contrast enhancement may be affected by the amount of pancreatic acini. AB

13. Lipoma (A) EUS shows a homogeneous hyperechoic mass (arrow) in the submucosal layer of antrum, and (B) the corresponding lesion is demonstrated on axial CT image as a small nodule with fat density (arrow head). Confirmative diagnosis of lipoma can be made with CT regardless of small size. AB -2HU

14. (A) EUS shows a hypoechoic mass in the mucosal to submucosal lyers with central depression, and (B) the corresponding lesion is demonstrated on axial CT image as an endoluminal mass in 2 nd portion of the duodenum (arrow). (C) UGIS shows smooth surfaced filling defect with central ulceration in 2 nd portion of duodenum (arrow head). Duodenal calcinoid AB C

15. (A) EUS shows a homogeneous hyperechoic mass arising from the third sonographic layer, the submucosa (arrow), and (B) the corresponding submucosal lesion is depicted on axial CT imaging as a tiny enhancing lesion in the duodenal bulb (arrow head). Small calcinoids are candidates for endoscopic resection due to their origin from superficial layers. Duodenal calcinoid A B

16. Inflammatory fibroid polyp (A) EUS shows a iceberg-like protruding hypoechoic mass arising submucosal layers with focal mucosal tearing in the gastric body, and (B) the corresponding lesion is demonstrated on axial CT image as a well-defined low- attenuated submucosal mass (arrow) with intact overlying mucosa. Several perigastric LAP are combined. Endoscopic submucosal dissection revealed inflammatory fibroid polyp. AB

17. (A) Sagittal reformatted CECT show a small submucosal tumor (arrow head) in the anterior wall of gastric angle, and (B) Volume-rendered image presents the smooth well-defined submucosal mass. (C,D) The corresponding lesion is demonstrated on EUS as a mixed echogenic mass arising submucosal layer (arrow). Inflammatory fibroid polyp A B CD

18. Brunner’s gland hyperplasia (A) EUS shows a a submucosal mass with internal septated cystic lesion in the duodenal bulb, and (B) the corresponding lesion is demonstrated on coronal reformatted CT image as a small nodule with cystic change (arrow). AB

19. GIST (low risk) (A) EUS shows a homogeneous hypoechoic mass arising from the fourth sonographic layer, the muscularis propria, and (B) axial CT image of the corresponding submucosal mass presented as a homogeneous solid mass in the cardia (arrow head). (C) Another GIST on EUS displaying hypoechoic solid mass, arinsing from the muscularis propria. (D) Coronal reformatted CECT shows well-defined mass in the gastric body (arrow). AB C D

20. GIST (high risk) (A) EUS shows a hypoechoic solid mass with internal cystic lesion (arrow head), arising from the muscularis propria, and (B,C) axial and sagittal reformatted CECT show an exophytic solid mass with central low density area in gastric body (arrow). A B C

21. Leiomyoma (A) EUS shows a homogeneous hypoechoic mass arising from the muscularis propria in the gastric body, and (B) axial CT image of the corresponding submucosal mass presented as a homogeneous solid mass (arrow). Radiologic findings of leiomyoma in the gastroduodenal area are similar to other submucosal mesenchymal tumors like GIST. AB

22. (A) EUS shows a heterogeneous hypoechoic mass arising from the 2 nd sonographic layer, the muscularis mucosa in the gastric cardia, and (B) the corresponding lesion is demonstrated on axial CT image as a well-defined low-attenuated submucosal mass (arrow) with intact overlying mucosa. (C,D) T2WI and CET1 MRI show lobulated fungating mass with low SI and gradual enhancement. Gastric wedge resection revealed leiomyoma. Leiomyoma AB CD

23. Business order Business order EUS findings of various gastroduodenal lesionsEUS findings of various gastroduodenal lesions Comparison of EUS and MDCT Superiority of each modalities to correct diagnosis Advantage of MDCT over EUS

24. Extrinsic compression of the stomach Visceral cyst (A)EUS shows a homogeneous hypoechoic mass posterior to the gastric fundus, but gastric wall is intact. (B) The corresponding lesion is demonstrated on axial CT image as a splenic cyst (arrow head). (C) A protruding lesion in gastric fundus on EUS shows cystic mass with its contact surface with liver. (D) Coronal reformatted CECT reveals hepatic cyst with beak sign, indenting into lumen (arrow). A B C D

25. Extrinsic compression of the stomach Tortuous splenic artery (A) EUS shows a ill-defined, heterogeneous hypoechoic lesion posterior to gastric body with intact gastric wall (arrow), and (B) axial CT image of the corresponding area reveals tortuous splenic artery (arrow head). Retrospective analysis of EUS depicts serpiginous nature and continuity of vascular structures. AB

26. Tumor characterization with the use of contrast enhancement GIST (A) EUS shows a well-defined, solid mass mass arising from the muscularis propria in the stomach, and (B) coronal reformatted CT images of the corresponding gastric GIST shows target-like enhancement (arrow). AB

27. Tumor characterization with the use of contrast enhancement Hepatic hemangioma (A) EUS shows a homogeneous hypoechoic mass posterior to the gastric fundus, but gastric wall is intact (arrow). (B,C) Dynamic CT image present a enhancing mass (arrow head) with similar enhancement pattern of aorta. (D) Coronal reformatted CT shows pedunculated exophytic hepatic hemangioma (arrow) AC AB C D

28. Confirming diagnosis of gastric lipoma (A) EUS shows a homogeneous hyperechoic mass in the submucosal layer of antrum, and (B) Sagittal reformatted CECT enables a confirmative diagnosis of lipoma by identifying the low attenuated fat component (arrow). A B

29. Business order Business order EUS findings of various gastroduodenal lesionsEUS findings of various gastroduodenal lesions Comparison of EUS and MDCT Superiority of each modalities to correct diagnosis Advantage of EUS over MDCT

30. Protruding minor papilla mimicking duodenal mass (A,B) Axial and coronal CECT show a solid mass of the medial wall of duodenal 2 nd portion, and (C) MRCP presents a small polypoid nodule in the duodenum (arrow head). (D,E) The corresponding lesion is demonstrated on EUS as a protruding minor papilla (arrow). A B C D E

31. Difficulty of detecting small lesion at esophagogastric junction (A) Axial CECT shows edematous nodular thickening at EG junction (arrow), and (B) EUS demonstrates a well-defined, solid mass arising from the muscularis propria. Gastric wedge resection revealed GIST. A B

32. In the past, EUS was strictly reserved for the clinicians and radiologists only had CT available within reach. However, the current PACS era has enabled radiologists to gain easy access to EUS images, which is helpful for improving overall diagnostic accuracy through a comprehensive interpretation of both EUS and MDCT. CONCLUSION