Current Issue : July - September Volume : 2012 Issue Number : 3 Articles : 7 Articles
Background: With the development of increasingly sophisticated three-dimensional volumetric imaging methods,\r\ntumor volume can serve as a robust and reproducible measurement of drug efficacy. Since the use of molecularly\r\ntargeted agents in the clinic will almost certainly involve combinations with other therapeutic modalities, the use\r\nof volumetric determination can help to identify a dosing schedule of sequential combinations of cytostatic drugs\r\nresulting in long term control of tumor growth with minimal toxicity. The aim of this study is to assess high\r\nresolution sonography imaging for the in vivo monitoring of efficacy of Infliximab in pancreatic tumor.\r\nMethods: In the first experiment, primary orthotopic pancreatic tumor growth was measured with Infliximab\r\ntreatment. In the second experiment, orthotopic tumors were resected ten days after inoculation of tumor cells\r\nand tumor recurrence was measured following Infliximab treatment. Tumor progression was evaluated using 3D\r\nhigh resolution sonography.\r\nResults: Sonography measurement of tumor volume in vivo showed inhibitory effect of Infliximab on primary\r\ntumor growth in both non-resected and resected models. Measurement of the dynamics of tumor growth by\r\nsonography revealed that in the primary tumor Infliximab is effective against established tumors while in the\r\nresection model, Infliximab is more effective at an early stage following tumor resection. Infliximab treatment is\r\nalso effective in inhibiting tumor growth growth as a result of tumor cell contamination of the surgical field.\r\nConclusions: Clinical application of Infliximab is feasible in both the neoadjuvant and adjuvant setting. Infliximab is\r\nalso effective in slowing the growth of tumor growth under the peritoneum and may have application in treating\r\nperitoneal carcinomatosis. Finally the study demonstrates that high resolution sonography is a sensitive imaging\r\nmodality for the measurement of pancreatic tumor growth....
Background: There is recent interest in the role of carotid bifurcation anatomy, geometry and hemodynamic\r\nfactors in the pathogenesis of carotid artery atherosclerosis. Certain anatomical and geometric configurations at the\r\ncarotid bifurcation have been linked to disturbed flow. It has been proposed that vascular dimensions are selected\r\nto minimize energy required to maintain blood flow, and that this occurs when an exponent of 3 relates the radii\r\nof parent and daughter arteries. We evaluate whether the dimensions of bifurcation of the extracranial carotid\r\nartery follow this principle of minimum work.\r\nMethods: This study involved subjects who had computed tomographic angiography (CTA) at our institution\r\nbetween 2006 and 2007. Radii of the common, internal and external carotid arteries were determined. The\r\nexponent was determined for individual bifurcations using numerical methods and for the sample using nonlinear\r\nregression.\r\nResults: Mean age for 45 participants was 56.9 �± 16.5 years with 26 males. Prevalence of vascular risk factors was:\r\nhypertension-48%, smoking-23%, diabetes-16.7%, hyperlipidemia-51%, ischemic heart disease-18.7%.\r\nThe value of the exponent ranged from 1.3 to 1.6, depending on estimation methodology.\r\nConclusions: The principle of minimum work (defined by an exponent of 3) may not apply at the carotid\r\nbifurcation. Additional factors may play a role in the relationship between the radii of the parent and daughter\r\nvessels....
Background: Soft tissue foreign bodies are a common cause of orthopedic consultation in emergency\r\ndepartments. It is difficult to confirm their existence because conventional radiology only detects radio-opaque\r\nforeign bodies. Sonography can be a useful diagnostic method. The aim of this study is to evaluate diagnostic\r\naccuracy of sonography in detection and localization of non-opaque foreign bodies.\r\nMethods: We evaluated 47 patients with suspected foreign body retention in soft tissues by 10 MHz linear array\r\ntransducer. A single radiologist performed all examinations with 6 years� experience in musculoskeletal Sonography.\r\nWe detected and localized the presence of the foreign body in the soft tissue as guidance for facilitating the\r\nsurgery.\r\nResults: We detected soft tissue foreign body in 45 cases as hyperechoic foci. Posterior acoustic shadowing was\r\nseen in 36 cases and halo sign was seen in 5 cases due to abscess or granulation tissue formation. Surgery was\r\nperformed in 39 patients and 44 foreign bodies were removed.\r\nConclusion: Sonography is a useful modality in detection and localization of radiolucent foreign bodies in soft\r\ntissue which can avoid misdiagnosis during primary emergency evaluation....
Background: Computational analysis of tissue structure reveals sub-visual differences in tissue functional states by\r\nextracting quantitative signature features that establish a diagnostic profile. Incomplete and/or inaccurate profiles\r\ncontribute to misdiagnosis.\r\nMethods: In order to create more complete tissue structure profiles, we adapted our cell-graph method for\r\nextracting quantitative features from histopathology images to now capture temporospatial traits of threedimensional\r\ncollagen hydrogel cell cultures. Cell-graphs were proposed to characterize the spatial organization\r\nbetween the cells in tissues by exploiting graph theory wherein the nuclei of the cells constitute the nodes and\r\nthe approximate adjacency of cells are represented with edges. We chose 11 different cell types representing\r\nnon-tumorigenic, pre-cancerous, and malignant states from multiple tissue origins.\r\nResults: We built cell-graphs from the cellular hydrogel images and computed a large set of features describing\r\nthe structural characteristics captured by the graphs over time. Using three-mode tensor analysis, we identified the\r\nfive most significant features (metrics) that capture the compactness, clustering, and spatial uniformity of the 3D\r\narchitectural changes for each cell type throughout the time course. Importantly, four of these metrics are also the\r\ndiscriminative features for our histopathology data from our previous studies.\r\nConclusions: Together, these descriptive metrics provide rigorous quantitative representations of image\r\ninformation that other image analysis methods do not. Examining the changes in these five metrics allowed us to\r\neasily discriminate between all 11 cell types, whereas differences from visual examination of the images are not as\r\napparent. These results demonstrate that application of the cell-graph technique to 3D image data yields\r\ndiscriminative metrics that have the potential to improve the accuracy of image-based tissue profiles, and thus\r\nimprove the detection and diagnosis of disease....
Background: Magnetic resonance (MR) imaging has been described as the most important medical innovation in\r\nthe last 25 years. Over 80 million MR procedures are now performed each year and on average 2.3% (95%\r\nconfidence interval: 2.0 to 2.5%) of all patients scheduled for MR imaging suffer from claustrophobia. Thus,\r\nprevention of MR imaging by claustrophobia is a common problem and approximately 2,000,000 MR procedures\r\nworldwide cannot be completed due to this situation. Patients with claustrophobic anxiety are more likely to be\r\nfrightened and experience a feeling of confinement or being closed in during MR imaging. In these patients,\r\nconscious sedation and additional sequences (after sedation) may be necessary to complete the examinations.\r\nFurther improvements in MR design appear to be essential to alleviate this situation and broaden the applicability\r\nof MR imaging. A more open scanner configuration might help reduce claustrophobic reactions while maintaining\r\nimage quality and diagnostic accuracy.\r\nMethods/Design: We propose to analyze the rate of claustrophobic reactions, clinical utility, image quality, patient\r\nacceptance, and cost-effectiveness of an open MR scanner in a randomized comparison with a recently designed\r\nshort-bore but closed scanner with 97% noise reduction. The primary aim of this study is thus to determine\r\nwhether an open MR scanner can reduce claustrophobic reactions, thereby enabling more examinations of\r\nclaustrophobic patients without incurring the safety issues associated with conscious sedation. In this manuscript\r\nwe detail the methods and design of the prospective ââ?¬Å?CLAUSTROââ?¬Â trial.\r\nDiscussion: This randomized controlled trial will be the first direct comparison of open vertical and closed shortbore\r\nMR systems in regards to claustrophobia and image quality as well as diagnostic utility....
Background: Video capsule enteroscopy (VCE) has revolutionized small bowel imaging, enabling visual\r\nexamination of the mucosa of the entire small bowel, while MR enteroclysis (MRE) and CT enteroclysis (CTE) have\r\nlargely replaced conventional barium enteroclysis. A new indication for MRE and CTE is the clinical suspicion of\r\nsmall bowel strictures, as indicated by delayed or non-delivery of a test capsule given before a VCE examination, to\r\nexclude stenosis. The aim of this study was to determine the clinical value of subsequent MRE and CTE in patients\r\nin whom a test capsule did not present itself in due time.\r\nMethods: Seventy-five consecutive patients were identified with a delayed or unnoticed delivery of the test\r\ncapsule. Seventy patients consented to participate and underwent MRE (44) or CTE (26). The medical records and\r\nimaging studies were retrospectively reviewed and symptoms, laboratory results and imaging findings recorded.\r\nResults: Lesions compatible with Crohns disease were shown by MRE in 5 patients, by CTE in one and by VCE in\r\nfour, one of whom had lesions on MRE. In patients without alarm symptoms and findings (weight loss,\r\nhaematochezia, anaemia, nocturnal diarrheoa, ileus, fistula, abscess and abnormal blood tests) imaging studies did\r\nnot unveil any such lesion. VCE�s were performed in only 20 patients, mainly younger than 50 years of age,\r\nalthough no stenotic lesion was shown by MRE and CTE. In the remaining 50 patients no VCE or other endoscopic\r\nintervention was performed indicating that the referring physician was content with the diagnostic information\r\nfrom MRE or CTE.\r\nConclusion: The diagnostic value of MRE and CTE is sufficient for clinical management of most patients with\r\nsuspected small bowel disease, and thus VCE may be omitted or at least postponed for later usage....
Background: Magnetic Particle Imaging is a novel method for medical imaging. It can be used to measure the\r\nlocal concentration of a tracer material based on iron oxide nanoparticles. While the resulting images show the\r\ndistribution of the tracer material in phantoms or anatomic structures of subjects under examination, no\r\ninformation about the tissue is being acquired. To expand Magnetic Particle Imaging into the detection of soft\r\ntissue properties, a new method is proposed, which detects acoustic emissions caused by magnetization changes\r\nin superparamagnetic iron oxide.\r\nMethods: Starting from an introduction to the theory of acoustically detected Magnetic Particle Imaging, a\r\ncomparison to magnetically detected Magnetic Particle Imaging is presented. Furthermore, an experimental\r\nsetup for the detection of acoustic emissions is described, which consists of the necessary field generating\r\ncomponents, i.e. coils and permanent magnets, as well as a calibrated microphone to perform the detection.\r\nResults: The estimated detection limit of acoustic Magnetic Particle Imaging is comparable to the detection limit\r\nof magnetic resonance imaging for iron oxide nanoparticles, whereas both are inferior to the theoretical detection\r\nlimit for magnetically detected Magnetic Particle Imaging. Sufficient data was acquired to perform a comparison to\r\nthe simulated data. The experimental results are in agreement with the simulations. The remaining differences can\r\nbe well explained.\r\nConclusions: It was possible to demonstrate the detection of acoustic emissions of magnetic tracer materials in\r\nMagnetic Particle Imaging. The processing of acoustic emission in addition to the tracer distribution acquired by\r\nmagnetic detection might allow for the extraction of mechanical tissue parameters. Such parameters, like for\r\nexample the velocity of sound and the attenuation caused by the tissue, might also be used to support and\r\nimprove ultrasound imaging. However, the method can also be used to perform imaging on its own....
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