Beyond Conventional Endoscopic Ultrasound
Beyond Conventional Endoscopic Ultrasound
Purpose of review: Endoscopic ultrasound (EUS) recently became a technique with a major clinical impact in digestive diseases. EUS determines a change in the diagnosis and management of more than half of examined patients. This review summarizes recent advances in the complementary EUS examination modalities such as elastography and microbubble contrast enhancement.
Recent findings: EUS elastography is a well documented method that allows characterization and differentiation of pancreatic cancer and chronic pancreatitis. Quantitative elastography methods, especially based on computer analyses, retrieve numeric values and possibly eliminate the human bias. The use of contrast-enhanced EUS also allows a better visualization and differentiation of focal pancreatic lesions. A hypoenhanced mass as compared with the surrounding pancreatic parenchyma is highly suggestive for pancreatic adenocarcinoma, whereas a hyperenhanced lesion indicates an inflammatory mass. Furthermore, hybrid EUS imaging techniques (in combination with computed tomography or magnetic resonance) might be useful for an increased diagnostic confidence.
Summary: Despite its advantages in assessing the organs situated near the gastrointestinal tract, EUS is still an operator-dependent technique. The new EUS examination modalities incorporated in modern ultrasound systems allow a highly accurate diagnosis.
Endoscopic ultrasound (EUS) offers high-resolution images of the structures situated in the proximity of the gut and it is considered one of the most accurate methods for the diagnosis and staging of digestive cancers. It evolved in recent years into a technique with major clinical impact, especially in malignant diseases.
In many patients, transabdominal ultrasound is unable to visualize correctly the whole pancreas due to intervening air or fat. EUS provides high-resolution images of the pancreas, being the most appropriate imaging technique for the diagnosis of small tumors. Its sensitivity is equal to or greater than transabdominal ultrasound, computed tomography (CT) scan or MRI. Despite its advantage of assessing the pancreas at very close range, EUS is still imperfect in establishing the differential diagnosis between chronic pseudotumoral pancreatitis and pancreatic cancer. The specificity of the EUS images is quite low (around 50–60%), particularly for the diagnosis of malignant lymph nodes and pancreatic masses. Because histological assessment of the pancreas is difficult in most of the cases, different gold standards have been used to establish the optimum number of EUS criteria for diagnosis of benign disease. Pathology diagnosis is still considered the ideal gold standard, being rarely obtained from surgical specimens, EUS fine needle aspiration (EUS-FNA) or TruCut core biopsies.
Considering all these limitations, the last years' researches focused in at least two main directions, adding new techniques to conventional EUS, specifically designed to improve a noninvasive diagnosis: EUS elastography and contrast-enhanced harmonic EUS.
Abstract and Introduction
Abstract
Purpose of review: Endoscopic ultrasound (EUS) recently became a technique with a major clinical impact in digestive diseases. EUS determines a change in the diagnosis and management of more than half of examined patients. This review summarizes recent advances in the complementary EUS examination modalities such as elastography and microbubble contrast enhancement.
Recent findings: EUS elastography is a well documented method that allows characterization and differentiation of pancreatic cancer and chronic pancreatitis. Quantitative elastography methods, especially based on computer analyses, retrieve numeric values and possibly eliminate the human bias. The use of contrast-enhanced EUS also allows a better visualization and differentiation of focal pancreatic lesions. A hypoenhanced mass as compared with the surrounding pancreatic parenchyma is highly suggestive for pancreatic adenocarcinoma, whereas a hyperenhanced lesion indicates an inflammatory mass. Furthermore, hybrid EUS imaging techniques (in combination with computed tomography or magnetic resonance) might be useful for an increased diagnostic confidence.
Summary: Despite its advantages in assessing the organs situated near the gastrointestinal tract, EUS is still an operator-dependent technique. The new EUS examination modalities incorporated in modern ultrasound systems allow a highly accurate diagnosis.
Introduction
Endoscopic ultrasound (EUS) offers high-resolution images of the structures situated in the proximity of the gut and it is considered one of the most accurate methods for the diagnosis and staging of digestive cancers. It evolved in recent years into a technique with major clinical impact, especially in malignant diseases.
In many patients, transabdominal ultrasound is unable to visualize correctly the whole pancreas due to intervening air or fat. EUS provides high-resolution images of the pancreas, being the most appropriate imaging technique for the diagnosis of small tumors. Its sensitivity is equal to or greater than transabdominal ultrasound, computed tomography (CT) scan or MRI. Despite its advantage of assessing the pancreas at very close range, EUS is still imperfect in establishing the differential diagnosis between chronic pseudotumoral pancreatitis and pancreatic cancer. The specificity of the EUS images is quite low (around 50–60%), particularly for the diagnosis of malignant lymph nodes and pancreatic masses. Because histological assessment of the pancreas is difficult in most of the cases, different gold standards have been used to establish the optimum number of EUS criteria for diagnosis of benign disease. Pathology diagnosis is still considered the ideal gold standard, being rarely obtained from surgical specimens, EUS fine needle aspiration (EUS-FNA) or TruCut core biopsies.
Considering all these limitations, the last years' researches focused in at least two main directions, adding new techniques to conventional EUS, specifically designed to improve a noninvasive diagnosis: EUS elastography and contrast-enhanced harmonic EUS.
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