Imaging of the stomach and esophagus using CT and PET/CT techniques

Abstract

Multidetector computed tomography (MDCT) is the most frequently employed modality in the diagnostic evaluation of oncologic diseases of the abdomen and pelvis. Although upper-GI series have been used to evaluate the spectrum of infectious, inflammatory, and neoplastic esophageal and gastric diseases, fluoroscopic studies are limited in their ability to provide staging information about the status of gastric and esophageal tumors, including the presence of local and regional spread of tumor, as well the presence of distant metastases. By virtue of its ability to provide a global perspective of the gut wall, adjacent fat, and lymph nodes, as well as local and distal organs, CT has virtually replaced fluoroscopic techniques in the oncology patient, except for the evaluation of postoperative complications, swallowing, and esophageal motility disorders. With regard to oncologic staging, the major role of CT has been the depiction of lymph nodes and/or distant metastases. The sensitivity of conventional CT for the detection of esophageal and gastric cancer, especially early-stage cancer, is unsatisfactory due to poor conspicuity of the cancer against the normal gastric and/or esophageal wall. The sensitivity drops even further in the absence of lumen distension. Indeed, poorly distended hollow viscera on CT may result in both false-negatives, by obscuring small lesions, and false-positives, as folds mimic pseudolesions. Administering water or effervescent granules or the combination of both, prior to MDCT, overcomes these limitations, typically resulting in optimal esophageal and gastric wall visualization. The efficacy of overall TNM staging of esophageal and gastric cancer can be further increased with MDCT by using thin-slice sections with high-quality, isotropic, multiplanar reconstructions. These same techniques also improve the sensitivity of CT in the depiction of a broad spectrum of inflammatory and traumatic diseases of hollow organs. The introduction of FDG-PET in combination with MDCT has resulted in improved staging and management of patients with esophageal cancer and other malignant diseases, including gastrointestinal stromal tumor (GIST) and lymphoma. Indeed, FDG-PET-CT has now become part of the routine evaluation of esophageal cancers, but is less useful in gastric cancer and benign esophageal and gastric disorders. In this chapter, we review the value of the hydro-MDCT technique and the hydro-FDG-PET-CT technique in the diagnostic evaluation of esophageal and gastric diseases.