Dynamic contrast enhanced ultrasound in differential diagnosis of hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND Non-invasive differential diagnosis between hepatocellular carcinoma(HCC)and other liver cancer(i.e.cholangiocarcinoma or metastasis)is highly challenging and definitive diagnosis still relies on histological exam.The patterns of enhancement and wash-out of liver nodules can be used to stratify the risk of malignancy only in cirrhotic patients and HCC frequently shows atypical features.Dynamic contrast-enhanced ultrasound(DCEUS)with standardized software could help to overcome these obstacles,providing functional and quantitative parameters and potentially improving accuracy in the evaluation of tumor perfusion.AIM To explore clinical evidence regarding the application of DCEUS in the differential diagnosis of liver nodules.METHODS A comprehensive literature search of clinical studies was performed to identify the parameters of DCEUS that could relate to histological diagnosis.In accordance with the study protocol,a qualitative and quantitative analysis of the evidence was planned.RESULTS Rise time was significantly higher in HCC patients with a standardized mean difference(SMD)of 0.83(95%CI:0.48-1.18).Similarly,other statistically significant parameters were mean transit time local with a SMD of 0.73(95%CI:0.20-1.27),peak enhancement with a SMD of 0.37(95%CI:0.03-0.70),area wash-in area under the curve with a SMD of 0.47(95%CI:0.13-0.81),wash-out area under the curve with a SMD of 0.55(95%CI:0.21-0.89)and wash-in and wash-out area under the curve with SMD of 0.51(95%CI:0.17-0.85).SMD resulted not significant in fall time and wash-in rate,but the latter presented a trend towards greater values in HCC compared to intrahepatic cholangiocarcinoma.CONCLUSION DCEUS could improve non-invasive diagnosis of HCC,leading to less liver biopsy and early treatment.This quantitative analysis needs to be applied on larger cohorts to confirm these preliminary results.

Non-invasive evaluation of liver steatosis with imaging modalities:New techniques and applications

In the world,nonalcoholic fatty liver disease(NAFLD)accounts for majority of diffuse hepatic diseases.Notably,substantial liver fat accumulation can trigger and accelerate hepatic fibrosis,thus contributing to disease progression.Moreover,the presence of NAFLD not only puts adverse influences for liver but is also associated with an increased risk of type 2 diabetes and cardiovascular diseases.Therefore,early detection and quantified measurement of hepatic fat content are of great importance.Liver biopsy is currently the most accurate method for the evaluation of hepatic steatosis.However,liver biopsy has several limitations,namely,its invasiveness,sampling error,high cost and moderate intraobserver and interobserver reproducibility.Recently,various quantitative imaging techniques have been developed for the diagnosis and quantified measurement of hepatic fat content,including ultrasound-or magnetic resonancebased methods.These quantitative imaging techniques can provide objective continuous metrics associated with liver fat content and be recorded for comparison when patients receive check-ups to evaluate changes in liver fat content,which is useful for longitudinal follow-up.In this review,we introduce several imaging techniques and describe their diagnostic performance for the diagnosis and quantified measurement of hepatic fat content.

Design and simulation of a 2-D array flexible ultrasound transducer system for tissue characterization-A pilot study

Noninvasive diagnosis of bone density and mechanical properties using non-radiation imaging modality is an emerging area with promising in early prediction of osteopenia and treatment effectiveness in the clinic and functional disuse,i.e.,long-term bedrest and space mission.Advances in quantitative ultrasound have shown advantages in measuring both bone density and mechanical strength,non-radiation,imaging capability,and easy to use.The challenge that remained is the poor penetration of ultrasound signals passing through trabecular and cortical bones and acoustic energy scattering.A new scanning confocal ultrasound technology is developed in this lab to detect the alteration of bone to provide diagnostic results in bone density and structure properties.A software-controlled flexible ultrasound system with 2-D dual array transducer is developed and proposed for the purpose of noninvasive bone density diagnosis and assessment of bone loss.Transmitting(Tx)transducer elements are divided into sub-blocks to excite the ultrasound signals in sequence to decrease the system complexity while maintaining beam pattern properties by the signal processing procedure at receiving(Rx)side.Apodization is also applied to reduce acoustic side lobes and to make the resolution in the ultrasound field of view(FOV)more uniform.This study may provide basic understanding of modulated confocal ultrasound beam forming for tissue characterization,such as trabecular bone structual and strength properties.

A new method for validation of quantitative measurement by intravascular ultrasound in vivo

Studies in vitro show that intravascular ultrasound (IVUS) underestimates vessel and lumen dimensions. In order to validate IVUS measurement in vivo, we conducted a comparative study during catheterization in fifty patients. The patients underwent IVUS examinations for the purpose of diagnosis or treatment of coronary artery disease. The IVUS system was a 3.5 F, 20 MHz IVUS catheter (Sonicath catheter of Boston Scientific Co.) and a Hewlett Packard console. After examination of the coronary artery, the IVUS probe was withdrawn back into the guiding catheter to measure the average lumen diameter of the guiding catheter (8 F, Cordis). This measurement in vivo (VI) was compared with the true lumen diameter provided by the manufac Department of Cardiology, University of Essen, Essen, Germany (Liu FQ, Ge JB, Baumgart D, Haude M, Caspari G, Grge G, Eick B and Erbel R) turer (MA) and determined by on line quantitative angiography (HICOR, Siemens) (HI). In addition, the IVUS measurement in vitro (VT) was also taken with the same guiding catheter in waterbath at 37℃. The results showed that IVUS underestimated the true lumen diameter by 2.2%±2.6% in vivo, by 3.1%±1.8% in vitro, while HICOR owerestimated the true lumen diameter by 23.0%±6.8%. There was no difference between the IVUS measurements in vivo and in vitro. In summary, IVUS was very accurate for the measurement of a 8 F guiding catheter in vivo with only a minor underestimation, and IVUS measurement was far more reliable than the on line quantitative angiography.

The value of calcaneal quantitative ultrasound( QUS ) T score under- 2. 5 in predicting stroke

Objective To explore the relationship between risk of stroke and calcaneal quantitative ultrasound(QUS)T score under-2.5.Methods 5 847 subjects over the age of 40 from Yunyan District,Guiyang City were investigated with questionnaire,physical examination,blood lipids,other metabolic indexes and calcaneus bone