C Pirri

Measurement of Shear Wave Velocity Using Acoustic Radiation Force Impulse Imaging is not Hampered by Previous Use of Ultrasound Contrast Agents

PURPOSE To assess the inter-observer reproducibility of acoustic radiation force impulse imaging (ARFI) between 2 skilled physicians and to evaluate if ultrasound contrast agents (UCA) affect the measurement of shear wave velocity (SWV) using ARFI. PATIENTS AND METHODS 53 patients (29 males, 24 females, 59 ± 15 [22-84] years) who underwent contrast enhanced ultrasound (CEUS) examination were included. ARFI was performed on liver segment V by physicians A and B before CEUS, and by physician A within 4-6 minutes and 7-10 minutes after contrast injection. In a subgroup of 31 patients (15 males, 16 females, 57 ± 18 [22-84] years), ARFI was also performed on focal liver lesions (FLL) by physician A before CEUS, and within 4-6 minutes and 7-10 minutes after contrast injection. RESULTS The SWV values obtained by physician A and B before CEUS yielded an intra-class correlation coefficient value of 0.913 (95% CI, 0.849-0.950). No significant differences were shown between the SWV values of liver segment V in all 53 patients and of FLL in the subgroup of 31 patients obtained before CEUS and that of within 4-6 minutes and 7-10 minutes after contrast injection (all P > 0.05). CONCLUSION ARFI showed excellent inter-observer reproducibility between 2 skilled physicians. UCA did not affect the measurement of SWV in both liver parenchyma and FLL, at least when performed 4 minutes after the contrast injection. ARFI may become an additional tool in the differential diagnosis of FLL.

Contrast enhanced ultrasound of sentinel lymph nodes.

Sentinel lymph nodes are the first lymph nodes in the region that receive lymphatic drainage from a primary tumor. The detection or exclusion of sentinel lymph node micrometastases is critical in the staging of cancer, especially breast cancer and melanoma because it directly affects patients prognosis and surgical management. Currently, intraoperative sentinel lymph node biopsies using blue dye and radioisotopes are the method of choice for the detection of sentinel lymph node with high identification rate. In contrast, conventional ultrasound is not capable of detecting sentinel lymph nodes in most cases. Contrast enhanced ultrasound with contrast specific imaging modes has been used for the evaluation and diagnostic work-up of peripherally located suspected lymphadenopathy. The method allows for real-time analysis of all vascular phases and the visualization of intranodal focal “avascular” areas that represent necrosis or deposits of neoplastic cells. In recent years, a number of animal and human studies showed that contrast enhanced ultrasound can be also used for the detection of sentinel lymph node, and may become a potential application in clinical routine. Several contrast agents have been used in those studies, including albumin solution, hydroxyethylated starch, SonoVue®, Sonazoid® and Definity®. This review summarizes the current knowledge about the use of ultrasound techniques in detection and evaluation of sentinel lymph node.

The Pancreatic Head is Larger than often Assumed

Reference values for B-mode abdominal ultrasound are controversially discussed in the literature mainly due to the lack of data and non-standardized examination techniques. A cohort of 100 patients was prospectively examined. Patients with hepatobiliary diseases including gallstones, acute or chronic pancreatitis (n = 13) and non-adequate visualization (n = 10) were excluded from statistical analysis. Therefore, 77 patients were analyzed including 52 female and 25 male healthy subjects regarding the biliopancreatic system (median age ± SD: 56 ± 18 years [minimum: 22 and maximum 93 years]). The mean value of the cranio-caudal diameter of the pancreatic head was 49 ± 10 [26 - 77] mm(mean ± SD [minimum - maximum]) which is larger than usually reported except in one study. The size of the pancreatic head is often larger than assumed which is of importance to know to exclude pancreatic pathology below the level of the common bile duct.