Abstract
The aim of this chapter is to discuss the topography of the pancreas with an emphasis on the relationship between the gland and the surrounding vessels, then to review the traditional scanning techniques used in pancreatic sonography. Finally, we recommend some additional scanning techniques to increase diagnostic confidence. In the case of traditional scanning techniques, there is no single scanning method for observing the whole gland. Four principal sectional views should be recognized: a) The transverse view demonstrates the gland as well as vascular landmarks. The examination usually begins with the patient supine. The probe is located just below the xiphoid process. The splenic vein is the most important vascular landmark in this plane. It runs from right to left across the upper abdomen. The pancreatic body and tail are anterior to it. b) The sagittal view demonstrates the pancreas as an oval structure between the celiac axis and the superior mesenteric artery. The anteroposterior diameter and shape as well as the location vary considerably according to the respiratory condition. c) The oblique view in the right upper abdomen shows the superior mesenteric vein joining the splenic vein to form the main portal trunk. This vascular landmark is seen sandwiched between the pancreatic head anteriorly and the uncinate process posteriorly. d) The oblique view in the left intercostal space shows the spleen. The pancreatic tail appears as a homogenous band-like structure in the splenic hilus. The probe is usually placed near the left midaxillary line between ribs. Alternative scanning (our recommended) techniques are as follows a) It is especially important to rotate the probe to minimize the amount of gas in the stomach and duodenum as well as to widen appropriate acoustic windows. The pancreas can be clearly observed by rotating the probe, which allows a rapid and clear assessment of the gland. b) In difficult cases, the probe is located above the pancreatic head are obliquely radiate the beam toward the pancreatic tail, and then slide the probe above the pancreatic tail and obliquely radiate the beam toward the pancreatic head. This so-called “cross-line” method with/without probe rotation is suitable for easy visualization of the whole gland and the neighboring vessels. Conclusion: Some authors have advocated the uptake of 200 CC of water to use the water-filled stomach as an acoustic window. Others have recommended changing the patient's position to an oblique or erect position, for example. Other maneuvers include applying probe pressure on the area of interest on the abdomen. However, these techniques have had very little success. When traditional approaches have failed or provided limited results, the above alternative scanning techniques, although requiring additional effort to learn them,, will minimize the diagnostic problems currently inherent to traditional scanning methods.
