Endoscopic Ultrasound Elastography: the First Step towards Virtual Biopsy? Preliminary Results in 49 Patients

Background and Study Aims: It is well known that some diseases, such as cancer, lead to changes in the hardness of tissue. Sonoelastography, a technique that allows the elasticity of tissue to be assessed during ultrasound examination, provides the ultrasonographer with important additional information that can be used for diagnosis. The aim of this study was to evaluate the ability of endoscopic ultrasound elastography to differentiate between benign and malignant pancreatic masses and lymph nodes.
Patients and Methods: During a 12-month period, 49 patients underwent endoscopic ultrasound (EUS) examinations with elastography, conducted by a single endoscopist. Twenty-four patients underwent evaluation of a pancreatic mass (mean diameter 24.7 ± 11.1mm) and 25 underwent evaluation of 31 lymph nodes. The mean diameter of the lymph nodes was 19.7 ± 8.6 mm, and they were found in the cervical area (n = 3), mediastinum (n = 17), celiac arterial trunk region (n = 5), and aortocaval region (n = 6).
Results: The sonoelastography images of pancreatic masses were interpreted as benign in four cases and malignant in 20. The sensitivity and specificity of sonoelastography in the diagnosis of malignant lesions were 100 % and 67 %, respectively. The sonoelastography images of the lymph nodes were interpreted as showing malignancy in 22 cases, benign conditions in seven, and indeterminate status in two. The sensitivity and specificity of sonoelastography for evaluating malignant lymph-node invasion were 100 % and 50 %, respectively.
Conclusions: EUS elastography is potentially capable of further defining the tissue characteristics of benign and malignant lesions but specifity has to be improved. It can be used to guide biopsy sampling for diagnosis.

References

• 1 Bhutani M S, Hawes R H, Hoffman B J. A comparison of the accuracy of echo features during endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration for diagnosis of malignant lymph node invasion.  Gastrointest Endosc. 1997;  45 474-479
• 2 Tamerisa R, Irisawa A, Bhutani M S. Endoscopic ultrasound in the diagnosis, staging, and management of gastrointestinal and adjacent malignancies.  Med Clin North Am. 2005;  89 139-158, viii
• 3 Gress F, Michael H, Gelrud D. et al . EUS-guided fine-needle aspiration of the pancreas: evaluation of pancreatitis as a complication.  Gastrointest Endosc. 2002;  56 864-867
• 4 Chaudhari M H, Forsberg F, Voodarla A. et al . Breast tumor vascularity identified by contrast enhanced ultrasound and pathology: initial results.  Ultrasonics. 2000;  38 105-109
• 5 Fornage B D. Recent advances in breast sonography.  JBR-BTR. 2000;  83 75-80
• 6 Garra B S, Cespedes E I, Ophir J. et al . Elastography of breast lesions: initial clinical results.  Radiology. 1997;  202 79-86
• 7 Evans D H, McDicken W N. Doppler ultrasound: physics, instrumentation, and signal processing, 2nd ed. New York; Wiley 1999
• 8 Gao L, Parker K J, Lerner R M, Levinson S F. Imaging of the elastic properties of tissue: a review.  Ultrasound Med Biol. 1996;  22 959-977
• 9 Ophir J, Cespedes E I, Garra B S. et al . Elastography: ultrasonic imaging of tissue strain and elastic modulus in vivo.  Eur J Ultrasound. 1996;  3 49-70
• 10 Doyley M M, Meaney P M, Bamber J C. Evaluation of an iterative reconstruction method for quantitative elastography.  Phys Med Biol. 2000;  45 1521-1540
• 11 Rubens D J, Hadley M A, Alam S K. et al . Sonoelasticity imaging of prostate cancer: in vitro results.  Radiology. 1995;  195 379-383
• 12 Giovannini M, Bories E, Pesenti C. et al . Sonoelastography guided by endoscopic ultrasound: the first step for virtual biopsy? Results in 14 patients with a pancreatic mass [abstract].  Endoscopy. 2004;  36 (Suppl 1) A43