Current Issue : January - March Volume : 2012 Issue Number : 1 Articles : 9 Articles
Background: During imaging of the normal esophagus, air is often detected. The purpose of this study was to\r\ndetermine the correlation between the appearance of air bubbles on imaging and Gastroesophageal Reflux\r\nDisease (GERD) symptoms.\r\nMethods: The cross-sectional imaging study was conducted at Rasole Akram Hospital, Tehran, Iran. A total of 44\r\npatients underwent X-ray computed tomography (CT) scanning; the presence of air in the esophagus and visible\r\non CT imaging was scrutinized.\r\nResults: The average age of the subjects was 59 and the male to female ratio was 0.83. We found a significant\r\nrelationship between the presence of GERD symptoms, the size of air bubbles and esophageal dilation (ED) on the\r\nCT scan.\r\nConclusions: Air bubbles in the esophagus may be seen frequently in CT scans, but their size and location can\r\nvary. The GERD symptoms can arise when a small diameter air column is present within the esophagus, especially\r\nin the middle and lower parts....
Background: Early diagnosis of osteoporosis can potentially decrease the risk of fractures and improve the quality\r\nof life. Detection of thin inferior cortices of the mandible on dental panoramic radiographs could be useful for\r\nidentifying postmenopausal women with low bone mineral density (BMD) or osteoporosis. The aim of our study\r\nwas to assess the diagnostic efficacy of using kernel-based support vector machine (SVM) learning regarding the\r\ncortical width of the mandible on dental panoramic radiographs to identify postmenopausal women with low\r\nBMD.\r\nMethods: We employed our newly adopted SVM method for continuous measurement of the cortical width of\r\nthe mandible on dental panoramic radiographs to identify women with low BMD or osteoporosis. The original\r\nX-ray image was enhanced, cortical boundaries were determined, distances among the upper and lower\r\nboundaries were evaluated and discrimination was performed by a radial basis function. We evaluated the\r\ndiagnostic efficacy of this newly developed method for identifying women with low BMD (BMD T-score of -1.0 or\r\nless) at the lumbar spine and femoral neck in 100 postmenopausal women (=50 years old) with no previous\r\ndiagnosis of osteoporosis. Sixty women were used for system training, and 40 were used in testing.\r\nResults: The sensitivity and specificity using RBF kernel-SVM method for identifying women with low BMD were\r\n90.9% [95% confidence interval (CI), 85.3-96.5] and 83.8% (95% CI, 76.6-91.0), respectively at the lumbar spine and\r\n90.0% (95% CI, 84.1-95.9) and 69.1% (95% CI, 60.1-78.6), respectively at the femoral neck. The sensitivity and\r\nspecificity for identifying women with low BMD at either the lumbar spine or femoral neck were 90.6% (95% CI,\r\n92.0-100) and 80.9% (95% CI, 71.0-86.9), respectively.\r\nConclusion: Our results suggest that the newly developed system with the SVM method would be useful for\r\nidentifying postmenopausal women with low skeletal BMD....
Background: The purpose of this study is to explore how a patient�s height and weight can be used to predict\r\nthe effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed\r\ntomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can\r\nbe misplaced or lost, a predictive model will enable the medical professional to quantify a patient�s cumulative\r\nradiation dose.\r\nMethods: One hundred mathematical phantoms of varying heights and weights were defined within an x-ray\r\nMonte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest\r\nabdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression\r\nmodel was experimentally verified using anthropomorphic phantoms and validated against a real patient\r\npopulation.\r\nResults: Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates\r\nof the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms.\r\nComparisons of the patient population effective doses show that the predictive model is within 33% of current\r\nmethods of estimating effective dose using machine-based parameters.\r\nConclusions: A patient�s height and weight can be used to estimate the effective dose from a chest abdomen\r\npelvis computed tomography scan. The presented predictive model can be used interchangeably with current\r\neffective dose estimating techniques that rely on computed tomography machine-based techniques....
Background: A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and\r\nfunctional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental\r\ntool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using\r\npreoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in\r\ntransferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides.\r\nMethods: In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental\r\ninformation into periodontal surgical field. The methodology is based on integrating 3D data of anatomical\r\n(impression and cast) and preoperative (radiographic template) models, obtained by both CT and optical scanning\r\nprocesses.\r\nResults: A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy\r\nof the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed\r\nto place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to\r\nmonitor all the errors, which have been occurring step by step manufacturing the physical templates.\r\nConclusions: The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has\r\ndemonstrated to be a valid support to control the precision of the various physical models adopted and to point\r\nout possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the\r\nproposed methodology....
Background: Early diagnosis of pulmonary hypertension (PH) can potentially improve survival and quality of life.\r\nDetecting PH using echocardiography is often insensitive in subjects with lung fibrosis or hyperinflation. Right\r\nheart catheterization (RHC) for the diagnosis of PH adds risk and expense due to its invasive nature. Pre-defined\r\nmeasurements utilizing computed tomography (CT) of the chest may be an alternative non-invasive method of\r\ndetecting PH.\r\nMethods: This study retrospectively reviewed 101 acutely hospitalized inpatients with heterogeneous diagnoses,\r\nwho consecutively underwent CT chest and RHC during the same admission. Two separate teams, each consisting\r\nof a radiologist and pulmonologist, blinded to clinical and RHC data, individually reviewed the chest CT�s.\r\nResults: Multiple regression analyses controlling for age, sex, ascending aortic diameter, body surface area, thoracic\r\ndiameter and pulmonary wedge pressure showed that a main pulmonary artery (PA) diameter =29 mm (odds ratio\r\n(OR) = 4.8), right descending PA diameter =19 mm (OR = 7.0), true right descending PA diameter = 16 mm (OR =\r\n4.1), true left descending PA diameter = 21 mm (OR = 15.5), right ventricular (RV) free wall = 6 mm (OR = 30.5),\r\nRV wall/left ventricular (LV) wall ratio =0.32 (OR = 8.8), RV/LV lumen ratio =1.28 (OR = 28.8), main PA/ascending\r\naorta ratio =0.84 (OR = 6.0) and main PA/descending aorta ratio = 1.29 (OR = 5.7) were significant predictors of PH\r\nin this population of hospitalized patients.\r\nConclusion: This combination of easily measured CT-based metrics may, upon confirmatory studies, aid in the\r\nnon-invasive detection of PH and hence in the determination of RHC candidacy in acutely hospitalized patients....
Background: The American Society of Nuclear Cardiology and the Society of Nuclear Medicine state that\r\nincorporation of attenuation-corrected (AC) images in myocardial perfusion scintigraphy (MPS) will improve image\r\nquality, interpretive certainty, and diagnostic accuracy. However, commonly used software packages for MPS\r\nusually include normal stress databases for non-attenuation corrected (NC) images but not for attenuationcorrected\r\n(AC) images. The aim of the study was to develop and compare different normal stress databases for\r\nMPS in relation to NC vs. AC images, male vs. female gender, and presence vs. absence of obesity. The principal\r\nhypothesis was that differences in mean count values between men and women would be smaller with AC than\r\nNC images, thereby allowing for construction and use of gender-independent AC stress database.\r\nMethods: Normal stress perfusion databases were developed with data from 126 male and 205 female patients\r\nwith normal MPS. The following comparisons were performed for all patients and separately for normal weight vs.\r\nobese patients: men vs. women for AC; men vs. women for NC; AC vs. NC for men; and AC vs. NC for women.\r\nResults: When comparing AC for men vs. women, only minor differences in mean count values were observed,\r\nand there were no differences for normal weight vs. obese patients. For all other analyses major differences were\r\nfound, particularly for the inferior wall.\r\nConclusions: The results support the hypothesis that it is possible to use not only gender independent but also\r\nweight independent AC stress databases....
Background: Together with diagnosis and treatment planning, a good knowledge of the root canal system and its\r\nfrequent variations is a necessity for successful root canal therapy. The selection of instrumentation techniques for\r\nvariants in internal anatomy of teeth has significant effects on the shaping ability and cleaning effectiveness. The\r\naim of this study was to reveal the differences made by including variations in the internal anatomy of premolars\r\ninto the study protocol for investigation of a single instrumentation technique (hand ProTaper instruments)\r\nassessed by microcomputed tomography and three-dimensional reconstruction.\r\nMethods: Five single-root premolars, whose root canal systems were classified into one of five types, were\r\nscanned with micro-CT before and after preparation with a hand ProTaper instrument. Instrumentation\r\ncharacteristics were measured quantitatively in 3-D using a customized application framework based on MeVisLab.\r\nNumeric values were obtained for canal surface area, volume, volume changes, percentage of untouched surface,\r\ndentin wall thickness, and the thickness of dentin removed. Preparation errors were also evaluated using a colorcoded\r\nreconstruction.\r\nResults: Canal volumes and surface areas were increased after instrumentation. Prepared canals of all five types\r\nwere straightened, with transportation toward the inner aspects of S-shaped or multiple curves. However, a ledge\r\nwas formed at the apical third curve of the type II canal system and a wide range in the percentage of unchanged\r\ncanal surfaces (27.4-83.0%) was recorded. The dentin walls were more than 0.3 mm thick except in a 1 mm zone\r\nfrom the apical surface and the hazardous area of the type II canal system after preparation with an F3 instrument.\r\nConclusions: The 3-D color-coded images showed different morphological changes in the five types of root canal\r\nsystems shaped with the same hand instrumentation technique. Premolars are among the most complex teeth for\r\nroot canal treatment and instrumentation techniques for the root canal systems of premolars should be selected\r\nindividually depending on the 3-D canal configuration of each tooth. Further study is needed to demonstrate the\r\ndifferences made by including variations in the internal anatomy of teeth into the study protocol of clinical RCT for\r\nidentifying the best preparation technique....
Background: To study the rules that apparent diffusion coefficient (ADC) changes with time and space in cerebral\r\ninfarction, and to provide the evidence in defining the infarction stages.\r\nMethods: 117 work-ups in 98 patients with cerebral infarction (12 hyperacute, 43 acute, 29 subacute, 10 steady,\r\nand 23 chronic infarctions) were imaged with both conventional MRI and diffusion weighted imaging. The average\r\nADC values, the relative ADC (rADC) values, and the ADC values or rADC values from the center to the periphery\r\nof the lesion were calculated.\r\nResults: The average ADC values and the rADC values of hyperacute and acute infarction lesion depressed\r\nobviously. rADC values in hyperacute and acute stage was minimized, and increased progressively as time passed\r\nand appeared as ââ?¬Å?pseudonormalââ?¬Â values in approximately 8 to 14 days. Thereafter, rADC values became greater\r\nthan normal in chronic stage. There was positive correlation between rADC values and time (P < 0.01). The ADC\r\nvalues and the rADC values in hyperacute and acute lesions had gradient signs that these lesions increased from\r\nthe center to the periphery. The ADC values and the rADC values in subacute lesions had adverse gradient signs\r\nthat these lesions decreased from the center to the periphery.\r\nConclusion: The ADC values of infarction lesions have evolution rules with time and space. The evolution rules\r\nwith time and those in space can be helpful to decide the clinical stage, and to provide the evidence in guiding\r\nthe treatment or judging the prognosis in infarction....
Blackground: It is well-known that Epstein-Barr virus (EBV) can affect the central nervous system (CNS).\r\nCase presentation: Herein the authors report unusual timely Magnetic Resonance Imaging (MRI) brain scan\r\nfindings in an immunocompetent patient with EBV encephalitis.\r\nDiffusion weighted MRI sequence performed during the acute phase of the disease was normal, whereas the Fast\r\nRelaxation Fast Spin Echo T2 image showed diffuse signal intensity changes in white matter. The enhancement\r\npattern suggested an inflammatory response restricted to the brain microcirculation. Acyclovir and corticosteroid\r\ntherapy was administered. After three weeks, all signal intensities returned to normal and the patient showed\r\nclinical recovery.\r\nConclusion: This report demonstrates that EBV in an immunocompetent adult can present with diffuse, reversible\r\nbrain white matter involvement in the acute phase of mononucleosis. Moreover, our case suggests that a negative\r\nDWI sequence is associated with a favorable improvement in severe EBV CNS infection. More extensive studies are\r\nneeded to assess what other instrumental data can help to distinguish viral lesions from other causes in the acute\r\nphase of disease....
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