High-accuracy patient-to-image registration for the facilitation of image-guided robotic microsurgery on the head

Image-guided microsurgery requires accuracies an order of magnitude higher than today's navigation systems provide. A critical step toward the achievement of such low-error requirements is a highly accurate and verified patient-to-image registration. With the aim of reducing target registration error to a level that would facilitate the use of image-guided robotic microsurgery on the rigid anatomy of the head, we have developed a semiautomatic fiducial detection technique. Automatic force-controlled localization of fiducials on the patient is achieved through the implementation of a robotic-controlled tactile search within the head of a standard surgical screw. Precise detection of the corresponding fiducials in the image data is realized using an automated model-based matching algorithm on high-resolution, isometric cone beam CT images. Verification of the registration technique on phantoms demonstrated that through the elimination of user variability, clinically relevant target registration errors of approximately 0.1 mm could be achieved.

From EEG dependency multichannel matching pursuit to sparse topographic EEG decomposition

In this work, we present a multichannel EEG decomposition model based on an adaptive topographic time-frequency approximation technique. It is an extension of the Matching Pursuit algorithm and called dependency multichannel matching pursuit (DMMP). It takes the physiologically explainable and statistically observable topographic dependencies between the channels into account, namely the spatial smoothness of neighboring electrodes that is implied by the electric leadfield. DMMP decomposes a multichannel signal as a weighted sum of atoms from a given dictionary where the single channels are represented from exactly the same subset of a complete dictionary. The decomposition is illustrated on topographical EEG data during different physiological conditions using a complete Gabor dictionary. Further the extension of the single-channel time-frequency distribution to a multichannel time-frequency distribution is given. This can be used for the visualization of the decomposition structure of multichannel EEG. A clustering procedure applied to the topographies, the vectors of the corresponding contribution of an atom to the signal in each channel produced by DMMP, leads to an extremely sparse topographic decomposition of the EEG.

Quantitation of Guggenheimella bovis and treponemes in bovine tissues related to digital dermatitis

Digital dermatitis is an inflammation of uncertain aetiology in the skin of the foot of cattle. In 2005, a novel microorganism, Guggenheimella bovis, was isolated from the advancing front of digital dermatitis lesions, suggesting a possible role in pathogenesis. In the present study, tissue samples of 20 affected cows were examined by quantitative PCR for G. bovis, treponemes and the total eubacterial load. High numbers of eubacteria and treponemes were found in most lesions, whereas only a few lesions contained Guggenheimella, and only at low concentrations. The results argue against the relevance of G. bovis in the aetiology of digital dermatitis in cattle, but are consistent with a role for treponemes.

A navigation system for percutaneous needle interventions based on PET/CT images: design, workflow and error analysis of soft tissue and bone punctures

Percutaneous needle intervention based on PET/CT images is effective, but exposes the patient to unnecessary radiation due to the increased number of CT scans required. Computer assisted intervention can reduce the number of scans, but requires handling, matching and visualization of two different datasets. While one dataset is used for target definition according to metabolism, the other is used for instrument guidance according to anatomical structures. No navigation systems capable of handling such data and performing PET/CT image-based procedures while following clinically approved protocols for oncologic percutaneous interventions are available. The need for such systems is emphasized in scenarios where the target can be located in different types of tissue such as bone and soft tissue. These two tissues require different clinical protocols for puncturing and may therefore give rise to different problems during the navigated intervention. Studies comparing the performance of navigated needle interventions targeting lesions located in these two types of tissue are not often found in the literature. Hence, this paper presents an optical navigation system for percutaneous needle interventions based on PET/CT images. The system provides viewers for guiding the physician to the target with real-time visualization of PET/CT datasets, and is able to handle targets located in both bone and soft tissue. The navigation system and the required clinical workflow were designed taking into consideration clinical protocols and requirements, and the system is thus operable by a single person, even during transition to the sterile phase. Both the system and the workflow were evaluated in an initial set of experiments simulating 41 lesions (23 located in bone tissue and 18 in soft tissue) in swine cadavers. We also measured and decomposed the overall system error into distinct error sources, which allowed for the identification of particularities involved in the process as well as highlighting the differences between bone and soft tissue punctures. An overall average error of 4.23 mm and 3.07 mm for bone and soft tissue punctures, respectively, demonstrated the feasibility of using this system for such interventions. The proposed system workflow was shown to be effective in separating the preparation from the sterile phase, as well as in keeping the system manageable by a single operator. Among the distinct sources of error, the user error based on the system accuracy (defined as the distance from the planned target to the actual needle tip) appeared to be the most significant. Bone punctures showed higher user error, whereas soft tissue punctures showed higher tissue deformation error.

Patient-Oriented SCORAD (PO-SCORAD): a new self-assessment scale in atopic dermatitis validated in Europe

BACKGROund: Patient-oriented medicine is an emerging concept, encouraged by the World Health Organization, to greater involvement of the patient in the management of chronic diseases. The Patient-Oriented SCORing Atopic Dermatitis (PO-SCORAD) index is a self-assessment score allowing the patient to comprehensively evaluate the actual course of atopic dermatitis (AD), using subjective and objective criteria derived mainly from the SCORAD, a validated AD severity clinical assessment tool.

How reliable and safe is full-body low-dose radiography (LODOX Statscan) in detecting foreign bodies ingested by adults?

OBJECTIVE: Foreign body ingestion is common and potentially lethal. This study evaluates the use of low-dose Statscans (LODOX) in emergency departments. DESIGN: This comparative cross-sectional study retrospectively assessed 28 289 digital chest x-rays and 2301 LODOX scans performed between 2006 and 2010 at a tertiary emergency centre. The radiographic appearance, image quality and location of ingested foreign bodies were evaluated in standard digital chest and LODOX radiography. The mean irradiation (μSv) and cumulative mean radiation dose per patient with the ingested foreign body were calculated according to literature-based data, together with the sensitivity and specificity for each modality. RESULTS: A total of 62 foreign bodies were detected in 39 patients, of whom 19 were investigated with LODOX and 20 with conventional digital chest radiography. Thirty-three foreign bodies were located in the two upper abdominal quadrants, 21 in the lower quadrants-which are not visible on conventional digital chest radiography-seven in the oesophagus and one in the bronchial system. The sensitivity and specificity of digital chest radiography were 44.4% and 94.1%, respectively, and for the LODOX Statscan 90% and 100%, respectively. The calculated mean radiation dose for LODOX investigations was 184 μS, compared with 524 μS for digital chest radiography. CONCLUSIONS: LODOX Statscan is superior to digital chest radiography in the diagnostic work-up of ingested foreign bodies because it makes it possible to enlarge the field of view to the entire body, has higher sensitivity and specificity, and reduces the radiation dose by 65%.

Endothelial cell antibody-mediated rejection and successful retransplantation in a heart transplanted patient

Antibody-mediated rejection (AMR) plays a significant role in cardiac allograft dysfunction, and recently a consensus regarding the diagnosis of AMR has been published. To our knowledge, it has not previously been reported that acute graft failure related to AMR, and antiendothelial cell antibodies can successfully be diagnosed to allow the patient to receive the outlined treatment and undergo a subsequent retransplantation.

Intravascular ultrasound-guided creation of re-entry sites to improve intermittent claudication in patients with aortic dissection

PURPOSE: To report percutaneous fenestration of aortic dissection flaps to relieve distal ischemia using a novel intravascular ultrasound (IVUS)-guided fenestration device. CASE REPORTS: Two men (47 and 62 years of age) with aortic dissection and intermittent claudication had percutaneous ultrasound-guided fenestration performed under local anesthesia. Using an ipsilateral transfemoral approach, the intimal flap was punctured under real-time IVUS guidance using a needle-catheter combination through which a guidewire was placed across the dissection flap into the false lumen. The fenestration was achieved using balloon catheters of increasing diameter introduced over the guidewire. Stenting of the re-entry was performed in 1 patient to equalize pressure across the dissection membrane in both lumens. The procedures were performed successfully and without complications. In both patients, ankle-brachial indexes improved from 0.76 to 1.07 and from 0.8 to 1.1, respectively. Both patients were without claudication at the 3- and 6-month follow-up examination. CONCLUSION: Percutaneous intravascular ultrasound-guided fenestration and stenting at the level of the iliac artery in aortic dissection patients with claudication is a technically feasible and safe procedure and relieves symptoms.

[A-mode ultrasonic pointer for navigated pelvic surgery]

Surgical navigation has proven to be a minimally invasive procedure that enables precise surgical interventions with reduced exposure to irradiation for patient and personnel. Fluoroscopy-based modules have prevailed on the market. For certain operations of the pelvis computed tomography is necessary with its high imaging quality and considerably larger scan volume. To enable navigation in these cases, matching of the CT data set and the patient's real pelvic bone is essential. The common pair point-matching algorithm is complemented by the surface-matching algorithm to achieve an even higher overall precision of the system. For conventional surface matching with a solid pointer, the bone has to be exposed from soft tissue quite extensively, using a solid pointer. This conflicts with the claim of computer-assisted surgery to be minimally invasive. We integrated an A-mode ultrasonic pointer with the intention to perform extended surface matching on the pelvic bone noninvasively. Related to the conventional method, comparable and to some extent even improved precision conditions could be established.

Estimating the patient's contribution during robot-assisted therapy

Robot-assisted therapy has become increasingly common in neurorehabilitation. Sophisticated controllers have been developed for robots to assist and cooperate with the patient. It is difficult for the patient to judge to what extent the robot contributes to the execution of a movement. Therefore, methods to comprehensively quantify the patient's contribution and provide feedback are of key importance. We developed a method comprehensively to estimate the patient's contribution by combining kinematic measures and the motor assistance applied. Inverse dynamic models of the robot and the passive human arm calculate the required torques to move the robot and the arm and build, together with the recorded motor torque, a metric (in percentage) that represents the patient's contribution to the movement. To evaluate the developed metric, 12 nondisabled subjects and 7 patients with neurological problems simulated instructed movement contributions. The results are compared with a common performance metric. The estimation shows very satisfying results for both groups, even though the arm model used was strongly simplified. Displaying this metric to patients during therapy can potentially motivate them to actively participate in the training.

Cultural Protectionism 2.0 : Updating Cultural Policy Tools for the Digital Age

This chapter explores cultural protectionism 2.0, i.e. the normative dimensions of cultural diversity policies in the global digital space, asking what adjustments are needed and in fact, how feasible the entire project of diversity regulation in this environment may be. The complexities of the shift from offline to online and from analogue to digital, and the inherent policy challenges are illustrated with some (positive and negative) instances of existing media initiatives. Taking into account the specificities of cyberspace and in a forward-looking manner, the chapter suggests some adjustments to current media policy practices in order to better serve the goal of sustainably diverse cultural environment.

Patient-Specific Semi-Supervised Learning for Postoperative Brain Tumor Segmentation

In contrast to preoperative brain tumor segmentation, the problem of postoperative brain tumor segmentation has been rarely approached so far. We present a fully-automatic segmentation method using multimodal magnetic resonance image data and patient-specific semi-supervised learning. The idea behind our semi-supervised approach is to effectively fuse information from both pre- and postoperative image data of the same patient to improve segmentation of the postoperative image. We pose image segmentation as a classification problem and solve it by adopting a semi-supervised decision forest. The method is evaluated on a cohort of 10 high-grade glioma patients, with segmentation performance and computation time comparable or superior to a state-of-the-art brain tumor segmentation method. Moreover, our results confirm that the inclusion of preoperative MR images lead to a better performance regarding postoperative brain tumor segmentation.