Noninvasive inter- and intrafractional motion control in ultrahypofractionated radiation therapy of prostate cancer using RayPilot HypoCath™-a substitute for gold fiducial-based IGRT?

Purpose: In ultrahypofractionated radiation concepts, managing of intrafractional motion is mandatory because tighter margins are used and random errors resulting from prostate movement are not averaged out over a large number of fractions. Noninvasive live monitoring of prostate movement is a desirable asset for LINAC-based prostate stereotactic body radiation therapy (SBRT).

Methods: We prospectively analyzed a novel live tracking device (RayPilot HypoCath™; Micropos Medical AB, Gothenburg, Sweden) where a transmitter is noninvasively positioned in the prostatic urethra using a Foley catheter in 12 patients undergoing ultrahypofractionated intensity-modulated radiation therapy (IMRT) of the prostate.

Risk-adapted moderate hypofractionation of prostate cancer : A prospective analysis of acute toxicity, QOL and outcome in 221 patients.

Purpose: Prostate cancer (PCA) is highly heterogeneous in terms of its oncologic outcome. We therefore aimed to tailor radiation treatment to the risk status by using three different hypofractionated radiation regimen differing in applied dose, use of rectum spacer, inclusion of pelvic lymph nodes (pLN) and use of androgen deprivation therapy (ADT). Here we report on acute toxicity, quality of life (QOL) and oncologic outcome at a median follow-up of 12 months.

Rectum-spacer related acute toxicity - endoscopy results of 403 prostate cancer patients after implantation of gel or balloon spacers.

Background: Rectal spacers are used to limit dose to the anterior rectal wall in high dose external beam radiation therapy of the prostate and have been shown to reduce radiation induced toxicity. Here we report the complication rate and toxicity of the implantation procedure in a large cohort of patients who have either received a gel- or balloon-type spacer.

Methods: In total, 403 patients received rectal spacing, 264 with balloon, 139 with gel.

An IGRT margin concept for pelvic lymph nodes in high-risk prostate cancer.

Purpose: Gold-marker-based image-guided radiation therapy (IGRT) of the prostate allows to correct for inter- and intrafraction motion and therefore to safely reduce margins for the prostate planning target volume (PTV). However, pelvic PTVs, when coadministered in a single plan (registered to gold markers [GM]), require reassessment of the margin concept since prostate movement is independent from the pelvic bony anatomy to which the lymphatics are usually referenced to.

Methods: We have therefore revisited prostate translational movement relative to the bony anatomy to obtain adequate margins for the pelvic PTVs compensating mismatch resulting from referencing pelvic target volumes to GMs in the prostate.

Laryngeal Elevation Velocity and Aspiration in Acute Ischemic Stroke Patients.

Objectives: Aspiration after stroke has been associated with aspiration pneumonia, which contributes to increased mortality of stroke. Laryngeal elevation is a core mechanism for protection from aspiration. Few studies have explored the predictive value of laryngeal elevation velocity for aspiration after stroke.

Clinical inter-rater reliability of postural control techniques.

Effectiveness of postural control techniques to compensate for oropharyngeal dysphagia have been recommended and used by several clinicians. However, the inter-rater reliability of these techniques is not well understood. The purpose of this study was to clarify the ambiguity of postural control techniques using statistical analyses.

3-dimensional digital reconstruction of the murine coronary system for the evaluation of chronic allograft vasculopathy.

Background: Chronic allograft vasculopathy (CAV) is a major mechanism of graft failure of transplanted organs in humans. Morphometric analysis of coronary arteries enables the quantitation of CAV in mouse models of heart transplantation. However, conventional histological procedures using single 2-dimensional sections limit the accuracy of CAV quantification.

Acoustic characteristics of voluntary expiratory sounds after swallow for detecting dysphagia.

This research was designed to investigate the acoustic characteristics of voluntary expiratory sounds after swallow for detecting dysphagia. Forty-nine patients with complaints of swallow difficulty received a videofluorographic (VF) examination. They were divided into three groups: nine who did not have any apparent disease (Group N), 22 patients with head and neck cancer (Group H&N) and 18 patients with other diseases including cerebrovascular disease (Group OD).

Effects of the reappearance of primitive reflexes on eating function and prognosis.

Aim: Primitive reflexes can reappear with diseases of the brain, particularly those affecting the frontal lobes. Most studies on primitive reflexes have reported an association between such reflexes and brain damage, and the clinical symptoms of dementia. These reflexes can also be present during eating; however, their effects on eating function are difficult to evaluate.

Interventional tool tracking using discrete optimization.

This work presents a novel scheme for tracking of motion and deformation of interventional tools such as guide-wires and catheters in fluoroscopic X-ray sequences. Being able to track and thus to estimate the correct positions of these tools is crucial in order to offer guidance enhancement during interventions. The task of estimating the apparent motion is particularly challenging due to the low signal-to-noise ratio (SNR) of fluoroscopic images and due to combined motion components originating from patient breathing and tool interactions performed by the physician.

Image-based characterization of thrombus formation in time-lapse DIC microscopy.

The characterization of thrombus formation in time-lapse DIC microscopy is of increased interest for identifying genes which account for atherothrombosis and coronary artery diseases (CADs). In particular, we are interested in large-scale studies on zebrafish, which result in large amount of data, and require automatic processing. In this work, we present an image-based solution for the automatized extraction of parameters quantifying the temporal development of thrombotic plugs.

Videoendoscopic assessment of swallowing function to predict the future incidence of pneumonia of the elderly.

The purpose of the present study was to examine what dysphagic signs identified by videoendoscopy (VE) could predict the incidence of pneumonia and body weight loss in elderly patients living in nursing homes. This study was performed at six nursing care facilities in Japan from March 2007 to February 2009. The 148 subjects (85·1 ± 8·0 years, male/female: 43/105) were evaluated for their feeding and swallowing movements by clinical and VE examinations during the consumption of a regular meal.

Joint thrombus and vessel segmentation using dynamic texture likelihoods and shape prior.

The segmentation of thrombus and vessel in microscopic image sequences is of high interest for identifying genes linked to cardiovascular diseases. This task is however challenging because of the low contrast and the highly dynamic conditions observed in time-lapse DIC in-vivo microscopic scenes. In this work, we introduce a probabilistic framework for the joint segmentation of thrombus and vessel regions.

Reconstruction of 3-D histology images by simultaneous deformable registration.

The reconstruction of histology sections into a 3-D volume receives increased attention due to its various applications in modern medical image analysis. To guarantee a geometrically coherent reconstruction, we propose a new way to register histological sections simuItaneously to previously acquired reference images and to neighboring slices in the stack. To this end, we formulate two potential functions and associate them to the same Markov random field through which we can efficiently find an optimal solution.

Comparison of three types of tongue pressure measurement devices.

A new tongue pressure device consisting of a simple and safe disposable probe and manometer has been developed. This report describes a study that examined the validity of the new device, comparing it to a widely used tongue pressure manometer, the Iowa Oral Performance Instrument (IOPI), and to the stable adhered three air-filled bulbs manometry system. The first test compared maximum tongue pressure measured with the new device and the IOPI (13 male, 9 female, 25.

Normal muscular activity during swallowing as measured by surface electromyography.

Objectives: Speech-language pathologists use surface electromyography biofeedback as a tool to facilitate swallowing treatment, particularly to improve swallowing strength and coordination. The present study sought to establish normative data of swallowing muscular activity as measured by surface electrodes in order to compare the performance of patients with dysphagia to normal swallow performance.

Methods: Thirty normal young (18 to 25 years of age) and elderly (60 or more years of age) subjects swallowed 3 bolus volumes (5, 10, and 20 mL) in 2 conditions: swallow-to-command and swallow-when-ready.

Linear intensity-based image registration by Markov random fields and discrete optimization.

We propose a framework for intensity-based registration of images by linear transformations, based on a discrete Markov random field (MRF) formulation. Here, the challenge arises from the fact that optimizing the energy associated with this problem requires a high-order MRF model. Currently, methods for optimizing such high-order models are less general, easy to use, and efficient, than methods for the popular second-order models.

Deformable 2D-3D registration of vascular structures in a one view scenario.

Alignment of angiographic 3D scans to 2D projections is an important issue for 3D depth perception and navigation during interventions. Currently, in a setting where only one 2D projection is available, methods employing a rigid transformation model present the state of the art for this problem. In this work, we introduce a method capable of deformably registering 3D vessel structures to a respective single projection of the scene.

3D dynamic roadmapping for abdominal catheterizations.

Despite rapid advances in interventional imaging, the navigation of a guide wire through abdominal vasculature remains, not only for novice radiologists, a difficult task. Since this navigation is mostly based on 2D fluoroscopic image sequences from one view, the process is slowed down significantly due to missing depth information and patient motion. We propose a novel approach for 3D dynamic roadmapping in deformable regions by predicting the location of the guide wire tip in a 3D vessel model from the tip's 2D location, respiratory motion analysis, and view geometry.

Segmentation-driven 2D-3D registration for abdominal catheter interventions.

2D-3D registration of abdominal angiographic data is a difficult problem due to hard time constraints during the intervention, different vessel contrast in volume and image, and motion blur caused by breathing. We propose a novel method for aligning 2D Digitally Subtracted Angiograms (DSA) to Computed Tomography Angiography (CTA) volumes, which requires no user interaction intrainterventionally. In an iterative process, we link 2D segmentation and 2D-3D registration using a probability map, which creates a common feature space where outliers in 2D and 3D are discarded consequently.

Planning and intraoperative visualization of liver catheterizations: new CTA protocol and 2D-3D registration method.

Rationale And Objectives: Two-dimensional and three-dimensional (2D-3D) registration for angiographic liver interventions is an unsolved problem mainly because of two reasons. First, a suitable protocol for computed tomography angiography (CTA) to contrast liver arteries is not used in clinical practice. Second, in spite of a valuable body of research results in the neuroradiology community, an adequate registration algorithm that addresses the difficult task of 2D-3D alignment of abdominal vessel structures has not been developed yet.

Comparison of surface electromyographic (sEMG) activity of submental muscles between the head lift and tongue press exercises as a therapeutic exercise for pharyngeal dysphagia.

Objective: The present study compared surface electromyographic (sEMG) activity obtained from the submental muscle group for a tongue press and a head lift exercise as potential therapeutic exercises for dysphagic elderly.

Materials And Methods: Fifty-three healthy volunteers with a mean age of 35.3 participated in this study.

New CTA protocol and 2D-3D registration method for liver catheterization.

2D-3D registration for angiographic liver interventions is an unsolved problem mainly because of two reasons. First, a suitable protocol for Computed Tomography Angiography (CTA) to contrast liver arteries is not used in clinical practice. Second, an adequate registration algorithm which addresses the difficult task of aligning deformed vessel structures has not been developed yet.

Identification of swallowing events from sEMG Signals Obtained from Healthy Adults.

Surface electromyography (sEMG) is being used with increasing frequency to identify the occurrence of swallowing, to describe swallow physiology, and to treat impaired swallowing function in dysphagic patients. Despite this increased utilization, limited information is available regarding the validity and reliability of investigators and clinicians to interpret sEMG data in reference to swallowing. This study examines the validity and interjudge reliability of swallow identification using sEMG records obtained from healthy adults.