Accuracy of endoscopic ultrasound elastography used for differential diagnosis of focal pancreatic masses: a multicenter study.

BACKGROUND AND STUDY AIMS: Endoscopic ultrasound (EUS) elastography represents a new imaging procedure that might characterize the differences of hardness and strain between diseased tissue and normal tissue. The aim of this study was to assess the efficiency of EUS elastography for the differentiation of focal masses in chronic pancreatitis and pancreatic cancer. PATIENTS AND METHODS: The study group comprised 258 patients with focal pancreatic masses included prospectively at 13 participating centers. Qualitative analysis of the diagnoses made by two expert doctors using all recorded video clips was performed in order to test the interobserver variability. A post-processing software analysis was used to examine the EUS elastography videos by calculating average-hue histograms of individual elastography images. The quantitative information was used to calculate intra-observer variability and the accuracy of the method. RESULTS: Qualitative analysis of the recorded videos revealed a kappa value of 0.72. Intra-observer variability analysis revealed that the single measure intraclass correlation ranged between 0.86 and 0.94. The average-hue histogram analysis of the data indicated a sensitivity of 93.4 %, a specificity of 66.0 %, a positive predictive value of 92.5 %, a negative predictive value of 68.9 %, and an overall accuracy of 85.4 %, based on a cut-off value of 175. Area under the receiver operating characteristic curve (AUROC) was 0.854 ( P < 0.0001) with a confidence interval of 0.804 - 0.894. CONCLUSION: The value of quantitative analysis of EUS elastography recordings was proven by good reproducibility of the videos, as well as good parameters of the AUROC analysis. (Clinical Trials.gov identifier: CT00909103).

Analysis of endoscopic ultrasound elastography used for characterisation and differentiation of benign and malignant lymph nodes.

PURPOSE: Ultrasound elastography is a new imaging procedure which allows the reconstruction of elasticity distribution by characterising the difference of hardness between pathological and normal tissue. MATERIALS AND METHODS: The aim of our study was to apply real-time elastography during endoscopic ultrasound (EUS) examinations and to consequently characterise benign versus malignant lymph nodes. The pattern of real-time EUS elastography images was compared with the conventional EUS aspects of lymph nodes and with the final diagnosis obtained by EUS-FNA cytology analysis and/or by surgical pathology. RESULTS: Patients diagnosed by EUS with cervical, mediastinal or abdominal lymph nodes were prospectively included, with a total number of 42 lymph nodes examined by EUS elastography. By using a qualitative pattern analysis, we were able to differentiate between benign and malignant lymph nodes with a high sensitivity, specificity and accuracy (91.7 %, 94.4 % and 92.86 %, respectively), based on five pre-defined patterns obtained on EUS elastography. A quantitative analysis based on histograms of the EUS elastography images also allowed an excellent discrimination between benign and malignant lymph nodes. Based on separate RGB channel histogram values, an "elasticity ratio" was further defined and yielded a sensitivity, specificity and accuracy for the differential diagnosis of 95.8 %, 94.4 % and 95.2 % respectively, based on a cut-off level of 0.84. CONCLUSION: EUS elastography is a promising method which allows characterisation and differentiation of benign and malignant lymph nodes with a high sensitivity, specificity and accuracy, offering complementary information added to conventional EUS imaging.

Immunohistochemical assessment of proliferating cell nuclear antigen in primary hepatocellular carcinoma and dysplastic nodules.

A complementary way for the assessment of HCC prognosis is represented by the analysis of molecular markers. Thus, immunohistochemical assessment of proliferation can describe tumor aggressiveness, probability of local recurrence or metastasis potential, being very useful for the assessment of recurrence-free survival and survival until death. The aim of our study was to assess proliferating cell nuclear antigen activity in HCC and dysplastic nodules as compared with surrounding non-neoplasic areas. Immunohistochemical techniques were thus performed on the samples obtained by ultrasound-guided liver biopsies or intraoperative biopsies, in 32 patients with HCC, as well as in 3 patients with dysplastic nodules occurring in liver cirrhosis. Expression of PCNA within extranodular areas of the HCC patients in the absence or presence of cirrhosis, was increasing from 40% to 70%, respectively. PCNA expression further increased within intranodular areas of dysplastic nodules and HCC, to 100% and 96.88%, respectively. A progressive increase of the mean values of PCNA-LI was also observed from extranodular areas without or with cirrhosis, towards intranodular areas of dysplastic nodules and HCC (4.2%, 6.8%, 27.9%, 31.9%, respectively). Dysplastic nodules can thus be considered lesions with a high-proliferation rate, representing an early stage of hepatocarcinogenesis. This supported the current recommendations for borderline hepatocellular nodules identified by ultrasound, which indicate an aggressive treatment similar to malignant lesions. In summary, we demonstrated a progressively increasing rate of cellular proliferation, from extranodular non-neoplasic areas to intranodular areas (dysplastic nodules and HCC), as reflected by an increased expression of proliferating cell nuclear antigen labelling index.