Ultrasonographic contrast medium improves the diagnostic accuracy of ultrasound-guided fine-needle aspiration

Currently, endoscopic ultrasound is considered the most sensitive method of detecting pancreatic and lymph node lesions, largely because of the possibility of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) [1], which is more sensitive than other imaging techniques (transabdominal ultrasonography, computed tomography, and magnetic resonance) [2] [3]. The specificity of EUS-FNA relies on the adequacy of the biopsy sample extraction. Published data show a diagnostic accuracy of EUS-FNA ranging from 81.5 % to 100 %, with an average of about 91 %. One report emphasizes that having the pathologist present during EUS-FNA increases the adequacy by 10 % [4]. Unfortunately, this is not possible in all centers, with consequent reduction of the sensitivity and specificity of the examination and, sometimes, a need to repeat the procedure. Reasons why a sample may not be diagnostic include problems related to operator skill and to the removal of interwoven necrotic tissue. To avoid this second problem, we usually use second-generation ultrasonographic contrast medium in order to better target the EUS-FNA at lymph node and pancreatic lesions [5] [6] [7] [8]. In our center we have assessed 66 consecutive EUS-FNA procedures performed up to 2006. The first 26 were done without contrast medium, the remaining 40 with contrast medium ([Fig. 1- 3]). In the first group of biopsy samples (10 pancreas, 16 lymph nodes) the adequacy was 80 % for the pancreas (8/10) and 68.75 % for lymph nodes (11/16). In the remaining 40 patients, the needle aspiration was carried out in the vascular area marked by the contrast medium. This adaptation of the method increased the adequacy of pancreatic lesion detection to 92.3 % (12/13) and that of lymph node lesions to 92.6 % (25/27), giving an average value of 92.5 %. In the light of this experience, we believe that the use of second-generation contrast medium for EUS-FNA should be encouraged in order to confirm the excellent results of our preliminary experience.

Fig. 1 Pancreatic insuloma. Ultrasound imaging a without and b with contrast medium.

Fig. 2 Hepatic angioma. Ultrasound imaging a without and b with contrast medium.

Fig. 3 Lymph node. Ultrasound imaging a without and b with contrast medium.

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