BACKGROUND: The ultrasonic vibrations from the piezoelectric knife may amplify the natural response to surgical injury. This may lead to different clinical and biological outcomes when using the piezoelectric knife versus a surgical bur to create selective cortical penetrations for alveolar ridge augmentation surgeries. The first aim of this study was to analyze the differences in bone graft healing when selective cortical penetrations are created with a surgical bur and with a piezoelectric knife. The second aim of this pilot study was to see if enhanced new bone formation during bone regeneration procedures can be achieved with the use of a piezoelectric knife versus the conventional bur or onlay grafting techniques utilizing deep learning, a subset of machine learning. MATERIALS & METHODS: he project was approved by the Boston University Medical Center Institutional Animal Care and Use Committee (IACUC). Twenty, 9-10 week male Sprague Dawley rats, weighing approximately 300g, were used in this study. The rats were randomly divided into three groups: Xenograft, Alloplast, and Collagen. These groups were further divided by surgical technique: Bur, Piezo, and Onlay. For the Bur and Piezo groups, four equally-spaced selective cortical penetrations were made prior to bone graft stabilization. Three rats served as controls (Control group). Microcomputed tomography scans (µCT) were acquired for each sample, containing approximately 1,000 slices of data each. After 28 days of healing the volumes of and density of the newly formed bone were extracted and analyzed for each group. This was achieved with an innovative deep learning algorithm designed for multi-level segmentation and regional feature detection utilizing convolutional neural networks (CNN). RESULTS: Microcomputed tomography (µCT) of our samples yielded very localized, high-resolution scans of our surgical samples. The innovative deep learning algorithm was able to reliably produce highly accurate, unbiased segmentations of our samples. This study demonstrated that new bone formation was possible with all nine of the tested surgical techniques, however the differences were not statistically significant. Selective cortical penetrations with a piezoelectric knife (PIEZO) resulted in significantly more “cortical-like” new bone formation at 28 days. CONCLUSION: Within the limitations of this preliminary study, it is possible to conclude that the piezoelectric knife is a valid alternative to conventional carbide burs when making selective cortical penetrations prior to bone grafting surgery. Additionally, our deep learning algorithm successfully segmented thousands of slices of data and allowed for the calculation of porosity and new bone volume in our samples.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24663号 / 農博第2546号 / 新制||農||1098(附属図書館) / 学位論文||R5||N5444(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 杉山 淳司, 教授 藤井 義久, 教授 仲村 匡司 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Please note: we were unable to immediately open the spreadsheet below. We repaired the spreadsheet file with Excel, and have a copy of it in storage. If you have difficulty opening the spreadsheet, please write to us at open-help@bu.edu. / Osteoarthritis (OA) is a painful, chronic, non-inflammatory disease affecting 140 million people worldwide that alters synovial joint structure and function. OA progressively breaks down hyaline cartilage, the hydrated tissue that provides a smooth, nearly frictionless surface and distributes loads applied to articulating joint surfaces. The loss of glycosaminoglycans (GAGs) from the extracellular matrix of cartilage is an early marker of OA. Therefore, imaging methods that quantify the GAG content of cartilage are of interest. This work investigates the synthesis and development of three cationic contrast agents (CAs) for imaging articular cartilage (AC): CA4+, an iodinated small molecule, and tantalum oxide nanoparticles (Ta2O5 NPs) for x-ray Computed Tomography (CT) imaging; and Gadopentetate-dilysine (Gd(DTPA)Lys2), a gadolinium small molecule for Magnetic Resonance (MR) imaging. These cationic contrast agents are attracted to the strong negative fixed charge of extracellular GAG and, therefore, infiltrate cartilage. This work begins with an overview of CT and MR imaging basic principles, current clinical CAs and contrast enhanced imaging of AC. First, the large-scale (50 g) synthesis of CA4+ is described and the partitioning over time of CA4+ into ex vivo AC is correlated to GAG content and cartilage mechanical properties. Similar partitioning studies are applied to anionic, neutral and cationic Ta2O5 NPs, where the cationic NP exhibited substantially greater affinity for AC. Moreover, by maintaining the positive charge on the NP surface and introducing a polyethylene glycol coating, a NP formulation is described for successful in vivo cartilage imaging. Next described is the MRI CA, Gd(DTPA)Lys2, which affords an equivalent T1 signal in cartilage at 1/10th the effective dosage of anionic gadopentetate. Finally, the equilibrium partitioning of the small molecule CT and MRI CAs is directly compared to GAG content and mechanical properties in human finger AC. In summary, results show cationic CAs strongly correlate to both GAG and mechanical properties and distribute in direct proportion to GAG unlike anionic CAs. The use of cationic CAs to quantify the biochemical and mechanical changes of AC may aid drug discovery and improve clinical assessment and intervention of OA for future patients. / 2017-11-03T00:00:00Z

The use of computed tomography in patients with gastrointestinal disease is increasing. However, the triple-phase computed tomographic angiographic appearance of the canine small intestine and the effects that phase of contrast enhancement and plane of reconstruction have on the appearance of the small intestine have not been fully evaluated. The purposes of this study were to investigate these effects on the appearance of the small intestinal wall. The minimal and maximal small intestinal diameter, wall thickness, number of wall layers identified, and degree of mucosal enhancement were recorded. The plane of reconstruction did not have any significant effects on wall thickness, diameter, degree of mucosal enhancement, or number of wall layers identified. There was a positive association between body weight and intestinal diameter. The arterial phase demonstrated the greatest mucosal enhancement and number of wall layers identified. The transverse plane was subjectively the most useful for evaluation of the small intestines.

Introduction The lifetime risk to develop acute appendicitis is estimated to 7-8%. Even if the condition iscommon and tools for diagnosis are existing, it is challenging to obtain a confident preoperativediagnosis which can explain differences in outcomes and complications. Aim The aim of this study was to analyze and compare differences in management and outcomesbetween patients with acute appendicitis at Karlstad Central Hospital. Methods The study was a retrospective cohort analysis comparing management between pediatric andadult patients and outcomes between patients who developed complications and patients who didnot at Karlstad central hospital between 2020-11-01 and 2021-05-31. Results Ultrasound was more often used in children than adults, 66.7% versus 10.5% (p=0.001), whereascomputed tomography (CT) was more used diagnosing adults, 73.5% versus 0% (p=<0.001). Inyounger adults (17-39) 69% had CT performed versus 96% in patients above 40 (p=<0.00005).Open appendectomy was more common among children, 25% versus 4.6% (p=<0.01) whilstlaparoscopic appendectomy was more common in adults, 90% versus 75% (p=<0.001). A longertime to intervention was seen in the adult complication group (p=0.004). Laparoscopicappendectomy was more common in the adult non-complication group 93.3% versus 78.10%(p=0.037). Conclusion There was a longer duration between admission and surgery and a higher initial CRP amongpatients that developed complications. Furthermore, in younger adults a high percentage of CTswhere performed compared to international guidelines. This indicates that there might be roomfor improvement in the management of appendicitis at CSK.

The AM60 Mg alloy has been used in the automotive industry to help achieve higher fuel efficiency. However, its products, mostly fabricated via high pressure die casting process, are inherently plagued with porosity issues. The presence of porosity impairs mechanical properties, especially fatigue properties, and thus affects the product reliability. We have therefore studied the effect of porosity on the fatigue behavior of samples drawn from a prototype AM60 shock tower by conducting strain-controlled fatigue test along with X-ray computed tomography (XCT). The 3D analysis of porosity by XCT showed discrepancies from 2D metallographic characterization. Fatigue testing results showed the machined surface is the preferential site for crack initiation to occur, on which pores are revealed after specimen extraction. A large scatter in fatigue life was observed as crack initiating at a large pore situated on the surface will result in a significantly shorter fatigue life. SEM fractography showed fracture surfaces are generally flat and full of randomly orientated serration patterns but without fatigue striations. The observations and measurements of porosity and fatigue cracks made by XCT were confirmed by SEM, supporting it as a reliable characterization tool for 3D objects and has value in assisting the failure analysis by SEM. Fatigue life was found to decrease with the increase of fatigue-crack-initiating pore size. The same trend was also found between the fatigue life and the volume fraction of porosity. The pore shape and pore orientation should be taken into account when determining the pore size as they can result in the difference in pore size between 2D and 3D measurement. / Thesis / Master of Applied Science (MASc) / The AM60 Mg alloy has been used in the automotive industry to help achieve higher fuel efficiency. However, its products, mostly fabricated via high pressure die casting process, are inherently plagued with porosity issues. The presence of porosity impairs mechanical properties, especially fatigue properties, and thus affects the product reliability. We have therefore studied the effect of porosity on the fatigue behavior of samples drawn from a prototype AM60 shock tower by conducting strain-controlled fatigue test along with X-ray computed tomography (XCT). The 3D analysis of porosity by XCT showed discrepancies from 2D metallographic characterization. Fatigue testing results showed the machined surface is the preferential site for crack initiation to occur, on which pores are revealed after specimen extraction. A large scatter in fatigue life was observed as crack initiating at a large pore situated on the surface will result in a significantly shorter fatigue life. SEM fractography showed fracture surfaces are generally flat and full of randomly orientated serration patterns but without fatigue striations. The observations and measurements of porosity and fatigue cracks made by XCT were confirmed by SEM, supporting it as a reliable characterization tool for 3D objects and has value in assisting the failure analysis by SEM. Fatigue life was found to decrease with the increase of fatigue-crack-initiating pore size. The same trend was also found between the fatigue life and the volume fraction of porosity. The pore shape and pore orientation should be taken into account when determining the pore size as they can result in the difference in pore size between 2D and 3D measurement.

Colonoscopy is essential for colorectal cancer screening and disease surveillance. It can remove pre-cancerous colon polyps to reduce a patient’s cancer risk. This thesis aims to improve colonoscopy’s localization using motion tracking and colonoscopy’s coverage using surface mapping. Chapter 4 describes an endoscope motion tracker that records the scope’s insertion length, rotation, and speed during a colonoscopy. The endoscope tracker’s motion record can be combined with the endoscope’s video to localize colon polyps or cancers. In the future, the device could record highly skilled manoeuvres performed by endoscopists to help train medical residents. It is difficult to image the colon’s mucosa because the colonoscope’s camera has a limited field of view. Chapter 3 uses a 180° fisheye camera to unwrap high resolution panoramas of a colon phantom. The panoramas are then combined into a mosaic map of the colon phantom’s surface. The colon’s surface is approximated as a cylinder. Follow up experiments could test our mapping algorithm using imagery from a wide-angle, high-definition colonoscope. Chapter 2 describes another technique to localize locations where polyps have been removed—blood vessel landmarks. Colonic blood vessels from a pig were imaged to determine if they could be used to fingerprint locations on the colon’s wall. Blood vessels are also useful image features for surface mapping. The proof-of-concept experiments successfully imaged large arteries but further work is needed to image the small capillaries in the colonic mucosa and to image the veins. In summary, we have visualized colonic blood vessels to test if they could be useful landmarks, tested using an extended field of view camera to create an unwrapped map of the colon wall, and designed an endoscope tracker to help localize abnormal tissue. Combining the endoscope tracker with the other two techniques should make is possible to accurately map the colon. / Thesis / Doctor of Philosophy (PhD) / Colonoscopy is a powerful tool for colon cancer screening. A colonoscopy can decrease the chance of developing advanced cancers by removing pre-cancerous polyps before they grow. This research works to improve colonoscopy’s localization using motion tracking and its coverage using surface mapping. We have developed an endoscope motion tracker that records the scope’s insertion length, rotation, and speed during a colonoscopy. It is In described in Chapter 4. The recorded motion can be combined with the endoscope’s video to improve colon cancer localization. Next, it is difficult to image the colon’s mucosa because the colonoscope’s camera has a limited field of view. Chapter 3 uses a 180° fisheye camera to unwrap high resolution panoramas of a colon phantom. The panoramas are then combined into a cylindrical surface map. Finally, Chapter 2 images the colon’s blood vessels to determine if they can fingerprint locations on the colon’s wall.

Texture analysis derived from computed tomography (CT) might be able to provide clinically relevant imaging biomarkers and might be associated with histopathological features in tumors. The present study sought to elucidate the possible associations between texture features derived from CT images with proliferation index Ki-67 and grading in pulmonary neuroendocrine tumors. Overall, 38 patients (n = 22 females, 58%) with a mean age of 60.8 ± 15.2 years were included into this retrospective study. The texture analysis was performed using the free available Mazda software. All tumors were histopathologically confirmed. In discrimination analysis, “S(1,1)SumEntrp” was significantly different between typical and atypical carcinoids (mean 1.74 ± 0.11 versus 1.79 ± 0.14, p = 0.007). The correlation analysis revealed a moderate positive association between Ki-67 index with the first order parameter kurtosis (r = 0.66, p = 0.001). Several other texture features were associated with the Ki-67 index, the highest correlation coefficient showed “S(4,4)InvDfMom” (r = 0.59, p = 0.004). Several texture features derived from CT were associated with the proliferation index Ki-67 and might therefore be a valuable novel biomarker in pulmonary neuroendocrine tumors. “Sumentrp” might be a promising parameter to aid in the discrimination between typical and atypical carcinoids.

The aim of this report is to study how machine learning can be used to reconstruct 2 dimensional computed tomography images from limited angle data. This could be used in a variety of applications where either the space or timeavailable for the CT scan limits the acquired data.In this study, three different types of models are considered. The first model uses filtered back projection (FBP) with a single learned filter, while the second uses a combination of multiple FBP:s with learned filters. The last model instead uses an FNO (Fourieer Neural Operator) layer to both inpaint and filter the limited angle data followed by a backprojection layer. The quality of the reconstructions are assessed both visually and statistically, using PSNR and SSIM measures.The results of this study show that while an FBP-based model using one or more trainable filter(s) can achieve better reconstructions than ones using an analytical Ram-Lak filter, their reconstructions still fail for small angle spans. Better results in the limited angle case can be achieved using the FNO-basedmodel.

Drug delivery systems (DDS) are essentially pharmaceutical products for human therapy, typically involving a mixture of active ingredients and excipients. Based upon quantitative characterization of structure, the thesis introduces the concept of classifying the architecture of DDS into four levels by their spatial scale and the life time period. The primary level is recognised as the static structure of the whole dosage form with a size from μm to cm with the final structure generated by formulation design. The secondary level categorises the structures of particles or sub-units to form a DDS with sizes from nm to mm as key units in processing such as mixing, grinding, granulation and packing; The tertiary level represents the dynamic structures of DDS during the drug release phase in vitro or in vivo incorporating the structure size range from nm to mm, which undergo changes during dissolution, swelling, erosion or diffusion. The spatial scale for the quaternary level is defined as the meso or micro scale architecture of active and non-active molecules within a DDS with sizes from Å to μm for the molecular structure of drug and excipients. Methods combining X-ray tomography, image processing, and 3D reconstructions have been devised and evaluated to study systematically pharmaceutical structures and correlate them with drug release kinetics of DDS. Based on the quantitative structural information of pharmaceutical intermediates and dosage forms, it is possible now to correlate structures with production processing, behaviour and function, and the static and dynamic structures of DDS with the release kinetics. Thus, a structure-guided methodology has been established for the research of DDS. / Chinese Academy of Sciences