Radiation dose optimization in pediatric temporal bone computed tomography: influence of tube tension on image contrast and image quality

Introduction: The purpose of this experimental study was to investigate the effect of tube tension reduction on image contrast and image quality in pediatric temporal bone computed tomography (CT). Methods: Seven lamb heads with infant-equivalent sizes were scanned repeatedly, using four tube tensions from 140 to 80kV while the CT-Dose Index (CTDI) was held constant. Scanning was repeated with four CTDI values from 30 to 3mGy. Image contrast was calculated for the middle ear as the Hounsfield unit (HU) difference between bone and air and for the inner ear as the HU difference between bone and fluid. The influence of tube tension on high-contrast detail delineation was evaluated using a phantom. The subjective image quality of eight middle and inner ear structures was assessed using a 4-point scale (scores 1-2 = insufficient; scores 3-4 = sufficient). Results: Middle and inner ear contrast showed a near linear increase with tube tension reduction (r = −0.94/−0.88) and was highest at 80kV. Tube tension had no influence on spatial resolution. Subjective image quality analysis showed significantly better scoring at lower tube tensions, with highest image quality at 80kV. However, image quality improvement was most relevant for low-dose scans. Conclusions: Image contrast in the temporal bone is significantly higher at low tube tensions, leading to a better subjective image quality. Highest contrast and best quality were found at 80kV. This image quality improvement might be utilized to further reduce the radiation dose in pediatric low-dose CT protocol

Surgical planning tool for robotically assisted hearing aid implantation

PURPOSE : For the facilitation of minimally invasive robotically performed direct cochlea access (DCA) procedure, a surgical planning tool which enables the surgeon to define landmarks for patient-to-image registration, identify the necessary anatomical structures and define a safe DCA trajectory using patient image data (typically computed tomography (CT) or cone beam CT) is required. To this end, a dedicated end-to-end software planning system for the planning of DCA procedures that addresses current deficiencies has been developed. METHODS :    Efficient and robust anatomical segmentation is achieved through the implementation of semiautomatic algorithms; high-accuracy patient-to-image registration is achieved via an automated model-based fiducial detection algorithm and functionality for the interactive definition of a safe drilling trajectory based on case-specific drill positioning uncertainty calculations was developed. RESULTS :    The accuracy and safety of the presented software tool were validated during the conduction of eight DCA procedures performed on cadaver heads. The plan for each ear was completed in less than 20 min, and no damage to vital structures occurred during the procedures. The integrated fiducial detection functionality enabled final positioning accuracies of [Formula: see text] mm. CONCLUSIONS :    Results of this study demonstrated that the proposed software system could aid in the safe planning of a DCA tunnel within an acceptable time

Simultaneous lesion and neuroanatomy segmentation in Multiple Sclerosis using deep neural networks

Segmentation of both white matter lesions and deep grey matter structures is an important task in the quantification of magnetic resonance imaging in multiple sclerosis. Typically these tasks are performed separately: in this paper we present a single segmentation solution based on convolutional neural networks (CNNs) for providing fast, reliable segmentations of multimodal magnetic resonance images into lesion classes and normal-appearing grey- and white-matter structures. We show substantial, statistically significant improvements in both Dice coefficient and in lesion-wise specificity and sensitivity, compared to previous approaches, and agreement with individual human raters in the range of human inter-rater variability. The method is trained on data gathered from a single centre: nonetheless, it performs well on data from centres, scanners and field-strengths not represented in the training dataset. A retrospective study found that the classifier successfully identified lesions missed by the human raters. Lesion labels were provided by human raters, while weak labels for other brain structures (including CSF, cortical grey matter, cortical white matter, cerebellum, amygdala, hippocampus, subcortical GM structures and choroid plexus) were provided by Freesurfer 5.3. The segmentations of these structures compared well, not only with Freesurfer 5.3, but also with FSL-First and Freesurfer 6.0

Artificial intelligence tools in clinical neuroradiology: essential medico-legal aspects

Commercial software based on artificial intelligence (AI) is entering clinical practice in neuroradiology. Consequently, medico-legal aspects of using Software as a Medical Device (SaMD) become increasingly important. These medico-legal issues warrant an interdisciplinary approach and may affect the way we work in daily practice. In this article, we seek to address three major topics: medical malpractice liability, regulation of AI-based medical devices, and privacy protection in shared medical imaging data, thereby focusing on the legal frameworks of the European Union and the USA. As many of the presented concepts are very complex and, in part, remain yet unsolved, this article is not meant to be comprehensive but rather thought-provoking. The goal is to engage clinical neuroradiologists in the debate and equip them to actively shape these topics in the future

Distended Seminal Vesicles Are Involved in Specific Cerebral Sexual Arousal: A Pilot Study Using Functional Brain Imaging in Young Healthy Men.

Background Whether seminal vesicles play a role in sexual activity in men is unknown. No study so far has compared the neural processing of visual sexual stimuli in men depending on the filling state of the seminal vesicles. Objective To evaluate potential specific cortical activation by visual sexual stimuli with distended and empty seminal vesicles. Design setting and participants A prospective case-control trial was conducted. Six male individuals underwent two visits on 2 consecutive days for hormone analyses; Derogatis Interview for Sexual Functioning (DISF) questionnaire; functional magnetic resonance imaging (fMRI) with passively viewing sexual, neutral, positive, and negative emotional pictures; and structural pelvic MRI. After the first visit, the participants had to empty seminal vesicles by masturbation. During fMRI, every participant viewed alternating blocks of sexual, neutral, positive, and negative emotional pictures. Outcome measurements and statistical analysis Comparisons between days 1 and 2 were evaluated using paired t tests. Results and limitations No significant differences were observed regarding hormone analyses, DISF questionnaire score, and arousal scoring between days 1 and 2. Seminal vesicle volume was significantly lower on day 2 (p = 0.003). Significantly higher activation was observed in the right precentral gyrus, middle frontal gyrus, and right superior temporal sulcus when contrasted for sexual over neutral (p < 0.05). Conclusions In response to pictures with sexual emotional content, significantly higher activation was detected in brain areas involved in motor preparation (arousal) and coding of desirability of visual sexual stimuli in men with distended seminal vesicles than in the same men with emptied seminal vesicles. This suggests that the filling state of the seminal vesicles may influence sexual desire in men. Patient summary We compared brain activity of men with filled and emptied seminal vesicles by functional magnetic resonance imaging. We found that men with filled seminal vesicles had higher activation of brain areas involved in arousal and sexual desire

A bone-thickness map as a guide for bone-anchored port implantation surgery in the temporal bone

The bone-anchored port (BAP) is an investigational implant, which is intended to be fixed on the temporal bone and provide vascular access. There are a number of implants taking advantage of the stability and available room in the temporal bone. These devices range from implantable hearing aids to percutaneous ports. During temporal bone surgery, injuring critical anatomical structures must be avoided. Several methods for computer-assisted temporal bone surgery are reported, which typically add an additional procedure for the patient. We propose a surgical guide in the form of a bone-thickness map displaying anatomical landmarks that can be used for planning of the surgery, and for the intra-operative decision of the implant’s location. The retro-auricular region of the temporal and parietal bone was marked on cone-beam computed tomography scans and tridimensional surfaces displaying the bone thickness were created from this space. We compared this method using a thickness map (n = 10) with conventional surgery without assistance (n = 5) in isolated human anatomical whole head specimens. The use of the thickness map reduced the rate of Dura Mater exposition from 100% to 20% and OPEN ACCESS Materials 2013, 6 5292 suppressed sigmoid sinus exposures. The study shows that a bone-thickness map can be used as a low-complexity method to improve patient’s safety during BAP surgery in the temporal bone

Surgical planning tool for robotically assisted hearing aid implantation

Purpose : For the facilitation of minimally invasive robotically performed direct cochlea access (DCA) procedure, a surgical planning tool which enables the surgeon to define landmarks for patient-to-image registration, identify the necessary anatomical structures and define a safe DCA trajectory using patient image data (typically computed tomography (CT) or cone beam CT) is required. To this end, a dedicated end-to-end software planning system for the planning of DCA procedures that addresses current deficiencies has been developed. Methods : Efficient and robust anatomical segmentation is achieved through the implementation of semiautomatic algorithms; high-accuracy patient-to-image registration is achieved via an automated model-based fiducial detection algorithm and functionality for the interactive definition of a safe drilling trajectory based on case-specific drill positioning uncertainty calculations was developed. Results : The accuracy and safety of the presented software tool were validated during the conduction of eight DCA procedures performed on cadaver heads. The plan for each ear was completed in less than 20min, and no damage to vital structures occurred during the procedures. The integrated fiducial detection functionality enabled final positioning accuracies of $$0.15\pm 0.08$$ 0.15 ± 0.08 mm. Conclusions : Results of this study demonstrated that the proposed software system could aid in the safe planning of a DCA tunnel within an acceptable time

Sono-Electro-Magnetic Therapy for Treating Chronic Pelvic Pain Syndrome in Men: A Randomized, Placebo-Controlled, Double-Blind Trial.

OBJECTIVE To assess the efficacy and safety of sono-electro-magnetic therapy compared to placebo in men with refractory CPPS. PATIENTS AND METHODS In a randomized, placebo-controlled, double-blind single center trial, we assessed the effect of sono-electro-magnetic therapy in men with treatment refractory CPPS. Sixty male patients were randomly assigned to treatment with either sono-electro-magnetic (n = 30) or placebo therapy (n = 30) for 12 weeks. The primary outcome was a change in the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) from baseline to 12 weeks. RESULTS The 12-week difference between sono-electro-magnetic and placebo therapy in changes of the NIH-CPSI total score was -3.1 points (95% CI -6.8 to 0.6, p = 0.11). In secondary comparisons of NIH-CPSI sub-scores, we found differences between groups most pronounced for the quality-of-life sub-score (difference at 12 weeks -1.6, 95% CI -2.8 to -0.4, p = 0.015). In stratified analyses, the benefit of sono-electro-magnetic therapy appeared more pronounced among patients who had a symptom duration of 12 months or less (difference in NIH-CPSI total score -8.3, 95% CI -14.5 to 2.6) than in patients with a longer symptom duration (-0.8, 95% CI -4.6 to 3.1; p for interaction = 0.023). CONCLUSIONS Sono-electro-magnetic therapy did not result in a significant improvement of symptoms in the overall cohort of treatment refractory CPPS patients compared to placebo treatment. Subgroup analysis indicates, however, that patients with a symptom-duration of 12 months or less may benefit from sono-electro-magnetic therapy, warranting larger randomized controlled trials in this subpopulation. TRIAL REGISTRATION ClinicalTrials.gov NCT00688506