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This study investigated the determination of detailed microstructure modeling of the trochlea of the superior oblique muscle (SOM) using micro-computed tomography (micro-CT) and modeling of a potential prototype for a trochlea implant using three-dimensional (3D) printing. We dissected 15 intact orbits of 15 embalmed cadavers. The trochleae of the SOM were detached from the periosteum. The specimens were stained by immersion in a 15% Lugol's solution. Images were reconstructed using conventional scanner software. Measurement points were determined for the middle cross section. Points P1 and P2 were selected where the SOM adjoined the curvature of the inner trochlea. They defined the inner contact points of the SOM in the inner part of the trochlea curvature. On the back of the trochlea, points P3 and P4 were selected at the uppermost and lowest points in the inner parts of the straight trochlea, respectively. Origin O was defined on the arcuate line of P 1 P 2 ^ to generate the smallest-diameter circle consisting of P1, O, and P2. We then measured the angle from O P 1 ¯ t o O P 2 ¯ , and from O P 3 ¯ t o O P 4 ¯. We also measured the distances O P 1 ¯ , O P 2 ¯ , O P 3 ¯ , a n d O P 4 ¯ for the design of a potential trochlea implant prototype using 3D-printing and micro-CT-based modeling. The distances O P 1 ¯ , O P 2 ¯ , O P 3 ¯ , a n d O P 4 ¯ were 2.2 ± 0.7, 1.4 ± 0.5, 2.7 ± 0.9, and 2.5 ± 0.4 mm (mean ± SD), respectively. The angles from O P 1 ¯ t o O P 2 ¯ , from O P 2 ¯ t o O P 4 , - and from O P 3 ¯ t o O P 4 ¯ were 100.7 ± 14.4, 66.3 ± 18.0, and 98.9 ± 24.9 degrees, respectively. The present investigation demonstrates that the high-resolution CT is a powerful imaging technique for defining the true 3D geometry of a specimen and can potentially be used to create a 3D-printed trochlea implant. [ABSTRACT FROM AUTHOR]

Moreover, there is often substantial remission of the original tumor following NAC, and the original tumor may scatter as multifocal or occult lesions, making accurate tumor localization difficult in current clinical practice. The authors found that the re-excision rate in the NAC group was significantly higher than that in the upfront surgery group (32% vs. 17%; I P i = 0.02) and that lobular carcinoma and estrogen receptor-positive tumors were associated with an increased risk of re-excision [[1]]. To the Editor, We read with interest the article by Devane et al., which examined the incidence and risk factors associated with re-excision after breast-conserving surgery following neoadjuvant chemotherapy (NAC) [[1]]. [Extracted from the article]

The mammalian brain is far superior to today's electronic circuits in intelligence and efficiency. Its functions are realized by the network of neurons connected via synapses. Much effort has been extended in finding satisfactory electronic neural networks that act like brains, i.e., especially the electronic version of synapse that is capable of the weight control and is independent of the external data storage. We demonstrate experimentally that a single metal-oxide-metal structure successfully stores the biological synaptic weight variations (synaptic plasticity) without any external storage node or circuit. Our device also demonstrates the reliability of plasticity experimentally with the model considering the time dependence of spikes. All these properties are embodied by the change of resistance level corresponding to the history of injected voltage-pulse signals. Moreover, we prove the capability of second-order learning of the multi-resistive device by applying it to the circuit composed of transistors. We anticipate our demonstration will invigorate the study of electronic neural networks using non-volatile multi-resistive device, which is simpler and superior compared to other storage devices. [ABSTRACT FROM AUTHOR]

In thoracoabdominal aortic aneurysm repair, repairing the visceral and segmental arteries is challenging. Although there is a pre-hand-sewn and multi-branched graft based on the conventional image-based technique, it has shortcomings in precisely positioning and directing the visceral and segmental arteries. Here, we introduce two new reconstruction techniques using patient-specific 3D-printed graft reconstruction guides: (1) model-based technique that presents the projected aortic graft, visualizing the main aortic body and its major branches and (2) guide-based technique in which the branching vessels in the visualization model are replaced by marking points identifiable by tactile sense. We demonstrate the effectiveness by evaluating conventional and new techniques based on accuracy, marking time requirement, reproducibility, and results of survey to surgeons on the perceived efficiency and efficacy. The graft reconstruction guides cover the segmentation, design, fabrication, post-processing, and clinical application of open surgical repair of thoracoabdominal aneurysm, and proved to be efficient for accurately reconstructing customized grafts. [ABSTRACT FROM AUTHOR]

We quantitatively evaluated breast tumor movement and volume changes between magnetic resonance imaging (MRI) scans in prone and supine positions. Twenty-seven breast tumor patients who received neoadjuvant systemic therapy (NST) for breast-conserving surgery were studied. Before and after NST, MRI scans in prone and supine positions were performed immediately. Tumor segmentation, volume, and position of tumors were evaluated in both positions. Average tumor volumes in prone and supine positions did not significantly differ (p = 0.877). Tumor movement from prone to supine positions from the origin of the bottom center of the sternum was strongly correlated with the distance from the tumor center to the chest wall (r = 0.669; p < 0.05). Tumor changes from prone to supine positions measured from the origin of the nipple depended on the location of the tumor in the breast. The prone-to-supine movement of all tumors from the origin of the bottom center of the sternum tended to move outward from the sagittal centerline of the body on the coronal plane, to the inside of the body on the sagittal plane, and outward and downward close to the body on the axial plane, which might help in planning operations using prone MRI in supine-position breast cancer surgery. [ABSTRACT FROM AUTHOR]

Segmentation is fundamental to medical image analysis. Recent advances in fully convolutional networks has enabled automatic segmentation; however, high labeling efforts and difficulty in acquiring sufficient and high-quality training data is still a challenge. In this study, a cascaded 3D U-Net with active learning to increase training efficiency with exceedingly limited data and reduce labeling efforts is proposed. Abdominal computed tomography images of 50 kidneys were used for training. In stage I, 20 kidneys with renal cell carcinoma and four substructures were used for training by manually labelling ground truths. In stage II, 20 kidneys from the previous stage and 20 newly added kidneys were used with convolutional neural net (CNN)-corrected labelling for the newly added data. Similarly, in stage III, 50 kidneys were used. The Dice similarity coefficient was increased with the completion of each stage, and shows superior performance when compared with a recent segmentation network based on 3D U-Net. The labeling time for CNN-corrected segmentation was reduced by more than half compared to that in manual segmentation. Active learning was therefore concluded to be capable of reducing labeling efforts through CNN-corrected segmentation and increase training efficiency by iterative learning with limited data. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate clinical outcomes of fluoroscopic removal of retrievable self-expandable metal stents (SEMSs) for malignant oesophageal strictures, to compare clinical outcomes of three different removal techniques, and to identify predictive factors of successful removal by the standard technique (primary technical success).Methods: A total of 137 stents were removed from 128 patients with malignant oesophageal strictures. Primary overall technical success and removal-related complications were evaluated. Logistic regression models were constructed to identify predictive factors of primary technical success.Results: Primary technical success rate was 78.8 % (108/137). Complications occurred in six (4.4 %) cases. Stent location in the upper oesophagus (P=0.004), stricture length over 8 cm (P=0.030), and proximal granulation tissue (P<0.001) were negative predictive factors of primary technical success. If granulation tissue was present at the proximal end, eversion technique was more frequently required (P=0.002).Conclusions: Fluoroscopic removal of retrievable SEMSs for malignant oesophageal strictures using three different removal techniques appeared to be safe and easy. The standard technique is safe and effective in the majority of patients. The presence of proximal granulation tissue, stent location in the upper oesophagus, and stricture length over 8 cm were negative predictive factors for primary technical success by standard extraction and may require a modified removal technique.Key Points: • Fluoroscopic retrievable SEMS removal is safe and effective. • Standard removal technique by traction is effective in the majority of patients. • Three negative predictive factors of primary technical success were identified. • Caution should be exercised during the removal in those situations. • Eversion technique is effective in cases of proximal granulation tissue. [ABSTRACT FROM AUTHOR]

Objectives: To validate 4D flow MRI in a flow phantom using a flowmeter and computational fluid dynamics (CFD) as reference.Methods: Validation of 4D flow MRI was performed using flow phantoms with 75 % and 90 % stenosis. The effect of spatial resolution on flow rate, peak velocity and flow patterns was investigated in coronal and axial scans. The accuracy of flow rate with 4D flow MRI was evaluated using a flowmeter as reference, and the peak velocity and flow patterns obtained were compared with CFD analysis results.Results: 4D flow MRI accurately measured the flow rate in proximal and distal regions of the stenosis (percent error ≤3.6 % in axial scanning with 1.6-mm resolution). The peak velocity of 4D flow MRI was underestimated by more than 22.8 %, especially from the second half of the stenosis. With 1-mm isotropic resolution, the maximum thickness of the recirculating flow region was estimated within a 1-mm difference, but the turbulent velocity fluctuations mostly disappeared in the post-stenotic region.Conclusion: 4D flow MRI accurately measures the flow rates in the proximal and distal regions of a stenosis in axial scan but has limitations in its estimation of peak velocity and turbulent characteristics.Key Points: • 4D flow MRI accurately measures the flow rate in axial scan. • The peak velocity was underestimated by 4D flow MRI. •4D flow MRI demonstrates the principal pattern of post-stenotic flow. [ABSTRACT FROM AUTHOR]

These authors contributed equally: Taehun Kim, Kyung Hwa Lee and Sungwon Ham Correction to: I Scientific Reports i https://doi.org/10.1038/s41598-019-57242-9, published online 15 January 2020 The original version of this Article contained an error in the spelling of the author Kyung Hwa Lee which was incorrectly given as Kyunghwa Lee. The original Article has been corrected. [Extracted from the article]