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A number of investigators have suggested that the early and late phases of the formalin test are mediated by separate neural systems. Evidence is presented which suggests that in addition to a dissociation between the two phases based on nociceptor stimulation and inflammation, the late phase of the formalin test is also dependent upon plasticity in the central nervous system which occurs during the transient early phase. Selectively blocking neural activity during the early phase with local anesthetics given peripherally, or in the cingulum bundle or fornix, prevents the development of these changes. Locally anesthetizing the cingulum bundle, fornix or medial bulboreticular formation prior to testing in the late phase produces analgesia which exceeds the duration of the anesthetic. It was also demonstrated that a thermal injury to the hindpaw or electrical stimulation of the sciatic nerve prior to neurectomy produces changes in the pattern and severity of self-mutilation following peripheral neurectomy, suggesting that the injury is encoded and maintained in central structures.

The four studies in this thesis deal with peripheral and central factors in phantom limb phenomena. Study 1 documents sensations referred to the phantom limb during transcutaneous electrical nerve stimulation (TENS) applied at the outer ears, face, and torso. The results suggest that some phantom sensations are maintained by activity of sympathetic fibers in the stump. Other sensations appear not to involve a peripheral mechanism. Studies 2 and 3 focus on sympathetic nervous system correlates of phantom sensations reported during TENS applied at the outer ears and contralateral leg. The results indicate that TENS significantly reduces the intensity of phantom limb paresthesias whereas a placebo control has no effect. Significant relationships between (a) phantom limb intensity and (b) stump skin conductance and temperature suggest that a cycle of sympathetic-efferent-somatic-afferent activity explains phantom limb paresthesias. Skin temperature was significantly lower at the stump than the intact limb in amputees with phantom limb pain (PLP), but not in those with a painless phantom, or no phantom limb at all, indicating that PLP is associated with reduced blood flow to the stump. Study 4 examines PLP that resembles pain experienced in the limb before amputation. These somatosensory memories constitute compelling evidence of a purely central component of PLP. Finally, amputees with and without PLP could not be differentiated by scores on personality, depression, or anxiety inventories. The results of the four studies indicate that the experience of phantom limb paresthesias involves a central mechanism that acts on peripheral structures whereas others qualities of experience depend exclusively on activation of central neural structures. Implications for treatment, research, and clinical practice are discussed.

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Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Recently, many studies have used T1 and T2 quantitative MRI in examining the brain and other body structures, to evaluate and follow up diseases, or simply for better understanding of the human body. Quality control on MRI scanners has been performed since the early eighties and nowadays the ACR MRI phantom is being used for the accreditation of the scanners, and quality control of their qualitative performance. In this study the same phantom is being used to obtain quantitative values of three regions in the phantom that might be used as reference for quantitative quality control. The results of the scans provided quantitative values that can be used as reference for the quality control of qMRI, and there was no difference after scanning the same regions twice. Further study is recommended to provide quantitative values for different MRI scanners strength to assure the use of ACR phantom as a tool for quality control of qMRI scanners. / 2031-01-02

Indiana University-Purdue University Indianapolis (IUPUI) / The primary objectives of this thesis are (1) to discuss the current understanding of phenomena associated with, proposed mechanisms of, and suggested treatments for amputation related pain, (2) to describe the software developed for analyzing results of a clinical study for the treatment of phantom limb pain (PLP), (3) to discuss the methods for a multi-center trial by the EPIONE consortium along with presenting preliminary results, and (4) to discuss the methods and results of a case study involving a new therapy modality for alleviating PLP. Each objective has been expanded into a chapter as described below. Chapter 1 serves as a literature review introducing the topic of amputation, associ- ated phenomena, and proposed mechanisms. The chapter also discusses the currently available treatments and the instruments used to measure PLP. Key topics include the definition of PLP, the prevalence of PLP, current treatment options for PLP, and experimental measurement of PLP. The final objective of this chapter is to introduce topics related to the investigation paradigm utilized for the studies following in Chapter 4 and Chapter 5. Therefore, a minor emphasis has been put on surface electrical stimulation (SES) and operant conditioning. As with any multi-center clinical study, coordination is key. Chapter 2 introduces the common clinical protocol (CCP) and methods of analysis for the clinical trials conducted by the EPIONE consortium. In order to analyze results in an automated fashion, a software tool was developed. This tool, the EPIONE Extraction Program (EEP) along with its extension the Group Analysis Module (GAM), is the focus of Chapter 3. A high-level overview of the requirements, process flow, and software testing are described. This chapter also discusses the methods of analysis for several self-report instruments used to determine effect size in Chapter 4 and Chapter 5. The outputs of the software tools make up the results presented and described in these chapters. In addition to the details included in Chapter 3, supplemental information is available in Appendix A and Appendix B, which are the detailed User Guides for the EEP and GAM. Chapter 4 reviews the pilot study data conducted by the EPIONE consortium. The primary and two secondary instruments used for analysis are discussed. This chapter provides a brief overview of results from the group. Each clinical site used slightly different variations of a common clinical protocol to better understand what effectively drives alleviation of PLP and to allow comparison of results. The work done at Indiana University - Purdue University Indianapolis (IUPUI) represents a small part of several other universities involved in the EPIONE consortium. Chapter 5 focuses on a case study at IUPUI with a more in-depth review of data collected throughout the study period. Using SES, we seek to reverse cortical reorganization by giving meaningful stimuli through existing circuitry. In this chapter the present work is discussed by introducing a case study in detail with an analysis of psychophysical data.

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Yes / Introduction: Scaphoid radiography has poor sensitivity for acute fracture detection and often requires repeat delayed imaging. Although magnetic resonance (MR) imaging is considered the gold standard, computed tomography (CT) is often used as an alternative due to ease of access. Cone-Beam CT (CBCT) offers equivalent diagnostic efficacy to Multi Slice CT (MSCT) at reduced dose. We aimed to establish the difference in scattered dose between modalities for scaphoid imaging. Methods: Anatomical regional entrance surface dose measurements were taken at 3 regions on an anthropomorphic torso phantom positioned as a patient to a wrist phantom undergoing scaphoid imaging for three modalities (CBCT, MSCT, four-view projection radiography). Exposure factors were based on audit of clinical exposures. Each dose measurement was repeated three times per anatomical region, modality, exposure setting and projection. Results: Under unpaired T-test CBCT gave significantly lower mean dose at the neck (1.64 vs 18 mGy), chest (2.78 vs 8.01) and abdomen (1.288 vs 2.93) than MSCT (p

To facilitate examination for osteogenesis and follow up after craniotomy similar head models called phantoms are made. The head phantom should emulate the tissues from a real head. This requires that the realistic head phantom have the same electrical properties as relative permittivity (dielectric constant) and conductivity. Both must be validated and matched for right frequency spectrum. Validation measurements are performed by a coaxial slim probe connected to an Agilent Technologies E8364B network analyzer. The range of frequency measured is from 1 to 50 GHz, but matching will only be processed for 1 to 10 GHz. The resonance frequency for the antenna or sensor, which later will be used, is 2.4 GHz. The end results of the head phantom consists of three different tissues or layers (skin, bone and brain). Cavities will be created in the bone and will act as different defects or stages of re-growing bone. Phantom cube is done for examining the influence of implant in bone. Insertions of cube samples are made to emulate intermediates between implant and bone. Keywords: agar, BMP, body morphogenetic protein, bone implant, brain phantom, craniosynostosis, craniotomy, cube phantom, phantom, re-growing bone, skin phantom, skull phantom, tissue.

Paramagnetic lanthanide ions have been investigated as possible MIR phantom materials and contrast agents. The aim of this study is to determine if it is possible to apply the well known Solomon-Bloembergen equations to solutions of paramagnetic lanthanide ions that have fast electron spin relaxation times, compared to Gadolinium, the most widely used ion for NMR. Studies of the relaxivity, frequency and temperature dependence, show that there is a considerable difference in those properties over the series. Chelation of the ions to EDTA and DTPA resulted in a decrease in the relaxivity which was directly proportional to the decrease in the number of water molecules in the inner co-ordination sphere. The fit of the Solomon-Bloembergen equations to the variable frequency and temperature relaxation times showed that theory is valid for the fast electron spin ions and allowed the calculation of the electron spin relaxation times. This showed that there is a difference of 5 orders of magnitude between Gadolinium, the ion demonstrated to have a slow electron spin relaxation time, and the remaining ions. The addition of EDTA chelated forms of these ions to agarose gels produced NMR phantom materials with relaxation time characteristics that could be chosen to fulfil a desired application. The biodistribution of Gd-DTPA was investigated using ESR and NMR. The concentration of Gd-DTPA in excised rat tissue, 20 minutes after intraperitoneal injection, was determined, by the change in NMR water proton relaxation time from that of a control tissue, and by ESR from direct measurement of the microwave power absorbed by the sample, which is directly proportional to the number of unpaired electron spins in the sample. The results from these two methods of determining contrast agent concentration agree well with each other both in the order of biodistribution and on the absolute concentrations.