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Diffusion‐based tractography in the optic nerve requires sampling strategies assisted by anatomical landmark information (regions of interest [ROIs]). We aimed to investigate the feasibility of expert‐placed, high‐resolution T1‐weighted ROI‐data transfer onto lower spatial resolution diffusion‐weighted images. Slab volumes from 20 volunteers were acquired and preprocessed including distortion bias correction and artifact reduction. Constrained spherical deconvolution was used to generate a directional diffusion information grid (fibre orientation distribution‐model [FOD]). Three neuroradiologists marked landmarks on both diffusion imaging variants and structural datasets. Structural ROI information (volumetric interpolated breath‐hold sequence [VIBE]) was respectively registered (linear with 6/12 degrees of freedom [DOF]) onto single‐shot EPI (ss‐EPI) and readout‐segmented EPI (rs‐EPI) volumes, respectively. All eight ROI/FOD‐combinations were compared in a targeted tractography task of the optic nerve pathway. Inter‐rater reliability for placed ROIs among experts was highest in VIBE images (lower confidence interval 0.84 to 0.97, mean 0.91) and lower in both ss‐EPI (0.61 to 0.95, mean 0.79) and rs‐EPI (0.59 to 0.86, mean 0.70). Tractography success rate based on streamline selection performance was highest in VIBE‐drawn ROIs registered (6‐DOF) onto rs‐EPI FOD (70.0% over 5%‐threshold, capped to failed ratio 39/16) followed by both 12‐DOF‐registered (67.5%; 41/16) and nonregistered VIBE (67.5%; 40/23). On ss‐EPI FOD, VIBE‐ROI‐datasets obtained fewer streamlines overall with each at 55.0% above 5%‐threshold and with lower capped to failed ratio (6‐DOF: 35/36; 12‐DOF: 34/34, nonregistered 33/36). The combination of VIBE‐placed ROIs (highest inter‐rater reliability) with 6‐DOF registration onto rs‐EPI targets (best streamline selection performance) is most suitable for white matter template generation required in group studies. [ABSTRACT FROM AUTHOR]

Simple Summary: In scientific research, there are various fields that require the simultaneous sampling of tissue and marking of mice shortly after birth. One approach is the amputation of the distal phalanx, a method that not only provides a lasting mark but also allows for the use of the removed tissue for early genotyping. While the use of this method is a topic of ongoing debate, it remains one of the safest and most widely employed techniques in current practice. The key lies in practical experience, ensuring the correct application of the method. To enhance and optimize this process, we have developed a 3D dummy specifically designed for training individuals in the precise amputation of the distal phalanx in 5-day-old mouse pups. In a recent seminar, we sought to evaluate the effectiveness of training on this innovative model and assess its appropriateness for the task at hand. The development of realistic dummies for training the distal phalanx amputation (DPA) technique in mouse pups is a promising alternative to reduce and replace animals in training for research and teaching. To test this, we obtained micro-CT data from postnatal day-five mouse pups, meticulously segmented them, and converted them into a 3D mesh format suitable for 3D printing. Once the dummy was printed, it was evaluated during actual training courses in two different groups: in the first group, users received no dummies to train the DPA, and in the second group, users were trained with three dummies. To assess the effectiveness of the dummy, we conducted a survey followed by an expert veterinarian evaluation. Our results showed that DPA is a complex procedure, and it is commonly poorly performed. When implementing the dummies, users who were not provided with dummies to practice only had an 8.3% success rate in DPA, while users provided with three dummies had a 45.5% success rate, respectively. Despite additional research being needed, our dummy offered improved practical training by providing a safe and effective alternative in line with ethical considerations while demonstrating the feasibility of using 3D printing technology to promote the 3Rs in experimental research. [ABSTRACT FROM AUTHOR]

Purpose This study investigated the differences in subjective and objective image parameters as well as dose exposure of photon-counting CT (PCCT) compared to cone-beam CT (CBCT) in paranasal sinus imaging for the assessment of rhinosinusitis and sinonasal anatomy. Methods This single-centre retrospective study included 100 patients, who underwent either clinically indicated PCCT or CBCT of the paranasal sinus. Two blinded experienced ENT radiologists graded image quality and delineation of specific anatomical structures on a 5-point Likert scale. In addition, contrast-to-noise ratio (CNR) and applied radiation doses were compared among both techniques. Results Image quality and delineation of bone structures in paranasal sinus PCCT was subjectively rated superior by both readers compared to CBCT (P  < .001). CNR was significantly higher for photon-counting CT (P  < .001). Mean effective dose for PCCT examinations was significantly lower than for CBCT (0.038 mSv ± 0.009 vs. 0.14 mSv ± 0.011; P  < .001). Conclusion In a performance comparison of PCCT and a modern CBCT scanner in paranasal sinus imaging, we demonstrated that first-use PCCT in clinical routine provides higher subjective image quality accompanied by higher CNR at close to a quarter of the dose exposure compared to CBCT. [ABSTRACT FROM AUTHOR]

Background: Mechanical thrombectomy is the standard treatment for acute ischemic stroke in patients with large vessel occlusion and can be performed up to 24h after symptom onset. Despite high recanalization rates, embolism in new territories has been reported in 8.6% of the cases. Causes for this could be clot abruption during stent retrieval into the smaller opening of a standard distal access catheter, and antegrade blood flow via collaterals despite proximal balloon protection. A funnel-shaped tip with a larger internal diameter was developed to increase the rate of first-pass recanalization and to improve the safety and efficacy of mechanical thrombectomy. Methods: This in vitro study compared the efficacy of a funnel-shaped tip with a standard tip in combination with different clot compositions. Mechanical thrombectomy was performed 80 times for each tip, using two stent retrievers (Trevo XP ProVue 3/20 mm, 4/20 mm) and four different clot types (hard vs. soft clots, 0–24h vs. 72h aged clots). Results: Significantly higher first-pass recanalization rates (mTICI 3) were observed for the funnel-shaped tip, 70.0% versus 30.0% for the standard tip (absolute difference, 32; relative difference 57.1%; P <.001), regardless of the clot type and stent retriever. Recanalization could be increased using harder Chandler loop clots versus softer statically generated clots, as well as 0–24h versus 72h aged clots, respectively. Conclusion: The funnel-shaped tip achieved higher first-pass recanalization rates than the smaller standard tip and lower rates of clot abruption at the tip. Clot compositions and aging times impacted recanalization rates. [ABSTRACT FROM AUTHOR]