Ct Scan

Respiratory motion is known to affect the quality of PET imaging of the thorax and abdomen, hindering the localization, detection of the lesions, and quantification of tracer uptake in a tumor. It also poses a challenge for the registration of PET and CT scans, even with a combined PET/CT scanner. Our long term goal is to study the impact of

Currently X-rays and computerized tomography (CT) scans are used to detect emphysema, but other tests are required to accurately quantify the amount of lung that has been affected by the disease. These images clearly show if a patient has emphysema, but are unable by visual scan alone, to quantify the degree of the disease, as it presents as subtle, dark spots on the lung. Our goal is to use these CT scans to accurately diagnose and determine emphysema severity levels in patients. This will be accomplished by performing several different analyses of CT scan images of several patients representing a wide range of severity of the disease. In addition to analyzing the original CT data, this process will convert the data to one and two bit images and will then examine the deviation from a normal distribution curve to determine skewness. Our preliminary results show that this method of assessment appears to be more accurate and robust than the currently utilized methods, which involve lo...

We investigated the feasibility and utilization of conductive plastic electrodes (CPEs) in patients undergoing continuous video-electroencephalographic (EEG) monitoring in the intensive care unit (ICU), and assessed the quality of brain magnetic resonance imaging (MRI) and computed tomography (CT) images obtained during this period. A total of 54 patients were monitored. Seizures were recorded in 16 patients. Twenty-five patients had neuroimaging performed with electrodes in place; 15 MRI and 23 CT scans were performed. All patients had excellent quality anatomical images without clinically significant artifacts, and without any signs or symptoms that raised safety concerns. Recording quality of the EEG was indistinguishable to that achieved with standard gold electrodes. The use of CPEs allowed for uninterrupted EEG recording of patients who required urgent neuroimaging, and decreased the amount of time spent by the technologists required to remove and reattach leads.

To determine the safety and tolerability of super-selective intra-arterial magnesium sulfate in combination with intra-arterial nicardipine in patients with cerebral vasospasm after subarachnoid hemorrhage. Patients were treated in a prospective protocol at two teaching medical centers. Emergent cerebral angiography was performed if there was either clinical, ultrasound, and/or computed tomographic (CT) perfusion deficits suggestive of cerebral vasospasm. Intra-arterial magnesium sulfate (0.25-1 g) was administered via a microcatheter in the affected vessels in combination with nicardipine (2.5-20.0 mg). Mean arterial pressures (MAP) and intracranial pressures (ICP) were monitored during the infusion. Immediate and sustained angiographic and clinical improvement was determined from post-treatment angiograms and clinical follow-up. Angiographic and clinical outcomes were compared to two published case series that has used nicardipine alone. A total of 58 vessels were treated in 14 patients (mean age 42 years; 11 women) with acute subarachnoid hemorrhage. The treatment was either intra-arterial nicardipine and magnesium sulfate alone or in conjunction with primary angioplasty. Forty vessels (69%) had immediate angiographic improvement with intra-arterial nicardipine and magnesium sulfate alone and 18 vessels (31%) required concomitant balloon angioplasty with complete reversal of the vasospasm. Retreatment was required in 13 vessels (22%) and the median time for retreatment was 2 days (range 1-13 days). Nicardipine treatment resulted in the reduction of MAP (12.3 mmHg, standard error [SE] 1.34, P-value <0.0001) without any significant change in ICP. Magnesium sulfate infusion was not associated with change in MAP or ICP. Among 31 procedures, immediate neurological improvement was observed in 22 (71%) procedures. In 12 (86%) patients, there were no infarctions in the follow-up CT scan acquired between 24 and 48 h. No statistical significant difference was observed in angiographic and clinical outcome of patients treated with the combination therapy in comparison with historical controls treated with nicardipine alone. Administration of intra-arterial magnesium sulfate in combination with nicardipine was well tolerated in patients with subarachnoid hemorrhage and cerebral vasospasm without a significant change in MAP and ICP. The efficacy of this combination therapy should be evaluated in a larger, controlled setting.

Carbonate reservoirs contain more than half the world's oil reserves, including highly productive reservoirs in Cretaceous and Cenozoic carbonates from the Middle East and Southeastern Asia. They are usually characterized by the complexity both of their internal architecture and of the distribution of their diagenetic fabrics which hampers crosshole correlations at various scales, and predictions regarding flow paths and volumes of fluids. Reservoir analogs can have the advantage of easier accessibility and sampling and less severe diagenetic alteration. Their study often provides information complementary to the knowledge of hydrocarbon reservoirs and it leads to a better understanding of carbonate systems, important to make better predictions on other potential reservoirs. Significant advances can be made from joint research in natural laboratories integrating outcrops and shallow boreholes, with extensive control on geophysical, geological and petrophysical parameters. The so...

The delineation of left atrium (LA) and pulmonary veins (PVs) anatomy from high resolution images holds importance for atrial fibrillation (AF) investigation and treatment. In this study, a semiautomatic segmentation procedure for LA and PVs inner surface from contrast enhanced CT data was developed. The procedure consists of a three dimensional marker controlled watershed segmentation applied to the external morphological gradient, followed by variable threshold surface extraction from the original intensity image. A preliminary anisotropic non-linear filtering was implemented to improve the S/N ratio of CT images. The performance of segmentation was evaluated on cardiac CT scans of 12 AF patients both qualitatively and quantitatively. The qualitative evaluation by expert radiologist assessed the segmentation as overall successful in all patients and capable of extracting both the LA body and the connected vascular trees. The quantitative validation, by computing discrepancy measures with respect to a manually segmented gold standard, indicated an average of about 90% of voxels correctly classified and an average border mismatch lower than 1.5 voxels (1.2 mm). The accurate extraction of the inner LA-PVs walls provided by this method, along with the minimal required human intervention, should facilitate the use of anatomical atrial models for the non-pharmacological treatment of AF.

... Soheila Khalilzadeh 1,2, Nooshin Baghaie 1, Azar Zamani 1, Jafar Shir Aghaei 1, Mohammad Reza Boloorsaz 1, and Ali Akbar Velayati 1 1 Department of Pediatrics, 2 Chronic Respiratory Disease Research Center, NRITLD, Shahid Beheshti University, MC, TEHRAN-IRAN. ...

The purpose of this study was to assess the importance of stereolithographic models (SLMs) for preoperative diagnosis and planning in craniofacial surgery and to examine whether these models offer valuable additional information as compared to normal CT scans and 3D CT images. Craniofacial SLMs of 20 patients with craniomaxillofacial pathology were made. A helical volume CT scan of the anatomic area involved delivered the necessary data for their construction. These were built with an SLA 250 stereolithography apparatus (3D-Systems, Valencia, CA, USA), steered by FORM-IT/DCS software (University of Zurich, Switzerland). The stereolithography models were classified according to pathology, type of surgery and their relevance for surgical planning. Though not objectively measurable, it was beyond doubt that relevant additional information for the surgeon was obtained in cases of hypertelorism, severe asymmetries of the neuro- and viscerocranium, complex cranial synostoses and large skull defects. The value of these models as realistic "duplicates" of complex or rare dysmorphic craniofacial pathology for the purpose of creating a didactic collection should also be emphasized. The models proved to be less useful in cases of consolidated fractures of the periorbital and naso-ethmoidal complex, except where there was major dislocation.

The Lagar Velho rock shelter became known worldwide since the discovery, in late 1998, of a nicely preserved Upper Paleolithic burial, containing an almost complete child skeleton, whose later anatomical study provided strong evidence for an admixture between the latest Neanderthal communities of Iberia and the first anatomically modern humans during the few millennia that the two populations co-existed. Given

Geopolymers are relatively novel materials with a wide range of potential application. The purpose of the present study was to experimentally investigate the composition‐microstructure‐property relationship of these materials. Na‐PSS geopolymers were prepared by thermally ...