Feasibility of tissue elastography using transcutaneous ultrasonography for the diagnosis of pancreatic diseases

Objectives:: We investigated the feasibility of using real-time tissue elastography (EG) with transcutaneous ultrasonography (EG-US) for pancreatic diseases. Methods:: A preliminary study (phase I) and a prospective (phase II) study were conducted. Phase I: subjects were 10 volunteers, 5 with cancer, 2 with endocrine tumor, 5 with chronic pancreatitis, 14 with intraductal papillary-mucinous neoplasm. To determine the characteristic EG images (diagnostic criteria for phase II), B-mode images were compared with EG images and histopathologic findings. Phase II: 53 consecutive patients were enrolled. The visualization rate by EG-US in lesions visualized by B mode was assessed, and the correct diagnosis rate by B mode alone (B diagnosis) or in combination with EG-US was evaluated. Results:: Phase I: normal parenchyma was a homogeneous color. In cancer, EG-US showed a markedly hard area with soft spots inside. Endocrine tumor was uniform and soft comparable to parenchyma. Chronic pancreatitis showed a mixture of various colors. Phase II: we identified 77.4% (41/53) of the lesions and observed 60.0% (15/25) of the cancers, 100% (3/3) of the endocrine tumor, 92.0% (23/25) of the cases of chronic pancreatitis cases on EG-US. The B-diagnosis rates ranged from about 70% to 80%. The diagnosis rates of the combination were more than 90% of lesions of each type. Conclusions:: The EG-US is feasible in the diagnosis of pancreatic diseases.