Imaging Findings in Gastrointestinal Cancer: Esophagus, Stomach
Before the introduction of endoscopy and the advent of Computer Tomography, conventional-barium meal-radiographic imaging of the upper gastrointestinal tract was the examination of choice for the detection of esophageal and gastric cancers. Nowadays compu
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51
Spyros D. Yarmenitis
51.1
Esophageal Cancer
According to the TNM staging system, described elsewhere in this section, the goal of imaging is to determine the local primary disease stage (T) represented by the depth of the cancer invasion through the esophageal wall, the presence (N1) or absence (N0) of locoregional nodal involvement along the esophageal course and to depict distant disease (M).
51.2
T Stage
51.2.1 Endoscopic US With EUS, a well-described pattern of five alternating hyperechoic and hypoechoic layers—from inner superficial mucosa to outer serosa—illustrates the normal sonographic appearance of the intact esophageal wall. Hence EUS is currently the most accurate modality to discriminate T1, T2 and T3 disease. Even more so, some reports claim that high-frequency EUS can distinguish mucosal from submucosal involvement. An overall average accuracy of EUS for T staging of esophageal cancer is reported to be 84 % and compared to
S. D. Yarmenitis (&) Department of Diagnostic radiology, Hygeia Hospital, 4, Erythrou Stavrou St, 15123, Maroussi, Greece e-mail: [email protected]
CT, EUS is found more accurate (EUS: 76–89 %, CT: 49–59 %) [1].
51.2.2 Computed Tomography The most important role of CT is the exclusion of T4 stage [2]. The CT criteria of invasion of adjacent structures/organs are mediastinal fat planes obliteration and displacement or indentation of neighboring mediastinal structures (Fig. 51.1). An 88–100 % sensitivity and 85–100 % specificity of CT is reported for detecting mediastinal invasion [3]. In particular if a 90 or more of the aortic circumference is in contact with the tumor or an obliteration of the triangular fat between the esophagus, spine and aorta is observed, aortic invasion should be considered [4] (Fig. 51.2). Displacement of the trachea or bronchus or indentation of the posterior tracheal wall is accurately indicative of tracheobronchial invasion [3]. Pericardial effusion and thickening of the pericardium or indentation of the heart margin and obliteration of fat plane are suggestive of pericardial invasion. CT compared to EUS is limited in determining the exact depth of wall infiltration by the tumor [5]. However, a wall thickness of more than 5 mm is considered abnormal whenever the esophagus is illustrated distended. Also any asymmetric thickening of the wall is a major but non-specific finding of esophageal cancer.
A. D. Gouliamos et al. (eds.), Imaging in Clinical Oncology, DOI: 10.1007/978-88-470-5385-4_51, Springer-Verlag Italia 2014
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S. D. Yarmenitis
Fig. 51.1 Cancer of the upper third of the esophagus (T) in contact with the tracheal border provoking indentation of the posterior tracheal wall
Fig. 51.3 CT scan sagittal reconstruction illustrates the upper and lower extension of a middle esophagus carcinoma (arrows). Image courtesy of Dr. Ch. Triantopoulou
Fig. 51.2 Esophageal cancer at the lower third of the organ that extends beyond the esophageal wall invading the mediastinal fat. Less than 90 degrees of the aortic circumfer
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