Advanced ultrasound techniques in arterial diseases.

Ultrasound (US) remains a valuable modality for the assessment of vascular diseases, with conventional sonographic techniques such as grayscale and Doppler US used extensively to assess carotid atherosclerosis and abdominal aortic aneurysms. However, conventional US techniques are inherently limited by factors such as operator dependency and limited field of view. There is an increasing interest in the use of advanced sonographic techniques such as contrast-enhanced US (CEUS) and 3-dimensional (3D) US to mitigate some of these limitations. Clinical applications of advanced sonographic techniques include surveillance of abdominal aortic aneurysm, post-endovascular aortic repair, and carotid atherosclerotic plaques. Recently published studies have demonstrated that CEUS and 3D US are superior to conventional US and comparable to computed tomography for certain vascular applications. Further research is required to fully validate the application of advanced sonographic techniques in evaluating various atherosclerotic diseases.

Advanced portal venous access techniques for transjugular intrahepatic portosystemic shunt placement.

INTRODUCTION: Transjugular intrahepatic portosystemic shunt (TIPS) placement is a well-established but technically challenging procedure for the management of sequelae of end-stage liver disease. Performed essentially blindly, traditional fluoroscopically guided TIPS placement requires multiple needle passes and prolonged radiation exposure to achieve successful portal venous access, thus increasing procedure time and the risk of periprocedural complications. Several advanced image-guided portal access techniques, including intracardiac echocardiography (ICE)-guided access, cone-beam CT (CBCT)-guided access and wire-targeting access techniques, can serve as alternatives to traditional CO2 portography-based TIPS creation. METHODS: A literature search was performed on the electronic databases including MEDLINE and Embase, from 2000 to the present to identify all relevant studies. The reference list also included studies identified manually, and studies referenced for other purposes. FINDINGS: The main benefit of these advanced access techniques is that they allow the operator to avoid essentially blind portal punctures, and the ability to visualise the target, thus reducing the number of required needle passes. Research has shown that ICE-guided access can decrease the radiation exposure, procedure time and complication rate in patients undergoing TIPS placement. This technique is particularly useful in patients with challenging portal venous anatomy. However, ICE-guided access requires additional equipment and possibly a second operator. Other studies have shown that CBCT-guided access, when compared with traditional fluoroscopy-guided access, provides superior visualisation of the anatomy with similar amount of radiation exposure and procedure time. The wire-targeting technique, on the other hand, appears to offer reductions in procedure time and radiation exposure by enabling real-time guidance. However, this technique necessitates percutaneous injury to the liver parenchyma in order to place the target wire. CONCLUSION: Advanced portal access techniques have certain advantages over the traditional fluoroscopically guided TIPS access. To date, few studies have compared these advanced guided access options, and further research is required.

Evaluating the frequency and severity of ovarian venous congestion on adult computed tomography.

PURPOSE: While pelvic congestion syndrome and chronic pelvic pain are relatively common in women, no large- or medium-sized studies have been conducted to our knowledge to evaluate the frequency and severity of ovarian vein dilatation (OVD) on computed tomography (CT). The purpose of our study was therefore to analyze a large number of consecutive abdominal and pelvic CT scans in adult women to determine OVD frequency and severity. METHODS: An IRB-approved, single-institution retrospective analysis of 1042 consecutive abdominal and pelvic CT scans in women ages 25-65 was performed. Scans were evaluated for the presence and severity of OVD and association with "nutcracker anatomy." A gradation scheme was developed based on quartile analysis. RESULTS: 143 of the CT scans had OVD (13.7%). Of the positive scans, 96 were bilateral, 29 were left-side only, 18 were right-side only, and 18 had nutcracker-type compression of the left renal vein (14.4% of scans with left or bilateral OVD). In positive scans, the mean and median left OVD were 7.5 and 7 mm, respectively, and right-side were 7.2 and 7 mm, respectively. Based on quartile analysis, OVD grading was mild (< 6 mm), moderate (6-8 mm), or severe (> 8 mm), with moderate including the middle 50% of patients. CONCLUSIONS: OVD was found on 13.7% of 1042 consecutive female abdominal and pelvic CT scans, with "nutcracker anatomy" present in 14.4% of the scans with left OVD. Moderate dilatation was defined as an OVD of 6-8 mm at the iliac crests.

Quantifying the association constant and stoichiometry of the complexation between colloidal polyacrylate-coated gold nanoparticles and chymotrypsin.

Qualitative and quantitative insights into the capacity and association constant for the binding of chymotrypsin to polyacrylate-coated gold nanoparticles is determined using fluorescence quenching, optical absorption and circular dichroism spectroscopy, isothermal calorimetry, and gel electrophoresis. The collective data reveal a binding capacity and constant for this particular system of ~7 and ~2 × 10(6) M(-1), respectively. These values vary among the individual techniques, and not all techniques are able to provide quantitative information. The present study demonstrates that accurately quantifying the association between nanoparticles and biological materials requires using multiple approaches to ensure consistency among the binding parameters determined.