Fire victim identification by post-mortem dental CT: Radiologic evaluation of restorative materials after exposure to high temperatures

The aim of this study was to evaluate the use of high resolution CT to radiologically define teeth filling material properties in terms of Hounsfield units after high temperature exposure.

Ultrasound-guided thoracic paravertebral puncture and placement of catheters in human cadavers: where do catheters go?

Paravertebral regional anaesthesia is used to treat pain after several surgical procedures. This study aimed to improve on our first published ultrasound-guided approach to the paravertebral space (PVS) and to investigate a possible discrepancy between the needle, catheter, and contrast dye position.

Ultrasound-guided spermatic cord block for scrotal surgery

Performing spermatic cord block for scrotal surgery avoids the potential risks of neuraxial and general anaesthesia and provides long-lasting postoperative analgesia. A blindly performed block is often inefficient and bears its own potential risks (intravascular injection of local anaesthetics, haematoma formation and perforation of the deferent duct). The use of ultrasound may help to overcome these disadvantages. The aim of this study was to test the feasibility and monitor the success rate of a new ultrasound-guided spermatic cord block.

Sonographic visualization and ultrasound-guided blockade of the greater occipital nerve: a comparison of two selective techniques confirmed by anatomical dissection

BACKGROUND: Local anaesthetic blocks of the greater occipital nerve (GON) are frequently performed in different types of headache, but no selective approaches exist. Our cadaver study compares the sonographic visibility of the nerve and the accuracy and specificity of ultrasound-guided injections at two different sites. METHODS: After sonographic measurements in 10 embalmed cadavers, 20 ultrasound-guided injections of the GON were performed with 0.1 ml of dye at the classical site (superior nuchal line) followed by 20 at a newly described site more proximal (C2, superficial to the obliquus capitis inferior muscle). The spread of dye and coloration of nerve were evaluated by dissection. RESULTS: The median sonographic diameter of the GON was 4.2 x 1.4 mm at the classical and 4.0 x 1.8 mm at the new site. The nerves were found at a median depth of 8 and 17.5 mm, respectively. In 16 of 20 in the classical approach and 20 of 20 in the new approach, the nerve was successfully coloured with the dye. This corresponds to a block success rate of 80% (95% confidence interval: 58-93%) vs 100% (95% confidence interval: 86-100%), which is statistically significant (McNemar's test, P=0.002). CONCLUSIONS: Our findings confirm that the GON can be visualized using ultrasound both at the level of the superior nuchal line and C2. This newly described approach superficial to the obliquus capitis inferior muscle has a higher success rate and should allow a more precise blockade of the nerve.

A Fully Automatic Calibration Framework for Navigated Ultrasound Imaging

Navigated ultrasound (US) imaging is used for the intra-operative acquisition of 3D image data during imageguided surgery. The presented approach includes the design of a compact and easy to use US calibration device and its integration into a software application for navigated liver surgery. User interaction during the calibration process is minimized through automatic detection of the calibration process followed by automatic image segmentation, calculation of the calibration transform and validation of the obtained result. This leads to a fast, interaction-free and fully automatic calibration procedure enabling intra-operative

Information Filtering for Ultrasound-based Real-time Registration

This paper presents methods based on Information Filters for solving matching problems with emphasis on real-time, or effectively real-time applications. Both applications discussed in this work deal with ultrasound-based rigid registration in computer-assisted orthopedic surgery. In the first application, the usual workflow of rigid registration is reformulated such that registration algorithms would iterate while the surgeon is acquiring ultrasound images of the anatomy to be operated. Using this effectively real-time approach to registration, the surgeon would then receive feedback in order to better gauge the quality of the final registration outcome. The second application considered in this paper circumvents the need to attach physical markers to bones for anatomical referencing. Experiments using anatomical objects immersed in water are performed in order to evaluate and compare the different methods presented herein, using both 2D as well as real-time 3D ultrasound.

Determination of Pelvic Orientation from Ultrasound Images Using Patch-SSMs and a Hierarchical Speed of Sound Compensation Strategy

In the field of computer assisted orthopedic surgery (CAOS) the anterior pelvic plane (APP) is a common concept to determine the pelvic orientation by digitizing distinct pelvic landmarks. As percutaneous palpation is - especially for obese patients - known to be error-prone, B-mode ultrasound (US) imaging could provide an alternative means. Several concepts of using ultrasound imaging to determine the APP landmarks have been introduced. In this paper we present a novel technique, which uses local patch statistical shape models (SSMs) and a hierarchical speed of sound compensation strategy for an accurate determination of the APP. These patches are independently matched and instantiated with respect to associated point clouds derived from the acquired ultrasound images. Potential inaccuracies due to the assumption of a constant speed of sound are compensated by an extended reconstruction scheme. We validated our method with in-vitro studies using a plastic bone covered with a soft-tissue simulation phantom and with a preliminary cadaver trial.

(99m)Tc-DPD-SPECT/CT predicts the outcome of imaging-guided diagnostic anaesthetic injections: A prospective cohort study

We hypothesized that bone SPECT combined with multiplanar reconstructed CT can identify and target the pain-inducing focus in the foot and can be used to successfully guide anaesthetic infiltrations. Therefore we prospectively investigated feasibility and predictive value of bone SPECT/CT for image guided diagnostic infiltrations in patients with chronic foot pain.

Small-animal PET/CT for monitoring the development and response to chemotherapy of thymic lymphoma in Trp53-/- mice

Transgenic mouse models of human cancers represent one of the most promising approaches to elucidate clinically relevant mechanisms of action and provide insights into the treatment efficacy of new antitumor drugs. The use of Trp53 transgenic mice (Trp53 knockout [Trp53(-/-)] mice) for these kinds of studies is, so far, restricted by limitations in detecting developing tumors and the lack of noninvasive tools for monitoring tumor growth, progression, and treatment response.