scholarly journals The value of Contrast-Enhanced Ultrasound in the characterization of vascular pattern of solid pancreatic lesions

2015 ◽  
Vol 17 (1) ◽  
pp. 16 ◽  
Author(s):  
Melania Ardelean ◽  
Roxana Sirli ◽  
Ioan Sporea ◽  
Simona Bota ◽  
Mirela Danila ◽  
...  
Keyword(s):  
Gold Standard ◽  
Imaging Techniques ◽  
Late Phase ◽  
Reference Method ◽  
Pancreatic Tumors ◽  
Imaging Method ◽  
Contrast Imaging ◽  
Cross Sectional ◽  
Solid Lesions

The aim of our study was to evaluate the accuracy of CEUS in the characterization of pancreatic solid lesions, considering cross sectional imaging techniques (CE-CT/MRI) as the “gold standard” methods. Material and methods: We performed a retrospective, monocentric study that included 91 solid pancreatic lesions which were evaluated by CEUS and by a second- line contrast imaging technique (CT or MRI), considered as the reference method. Results: The rate of a conclusive diagnosis based on a typical enhancement pattern was 94% (78/83 cases). In 72 cases out of 83 (86.7%) there was a perfect concordance between CEUS and the “gold-standard” imaging method (CE-CT/MRI). In our study, 88% (73/83) of the pancreatic lesions were categorized as malignant due to their typical wash-out aspect in the late phase. The overall accuracy of CEUS for the differential diagnosis of solid pancreatic tumors was approximately 81%. The accuracy of CEUS for the diagnosis of hypoen- hancing pancreatic tumors was approximately 89.1%; while for the diagnosis of hyperenhancing pancreatic tumors it was ap- proximately 72.8%. Conclusion: CEUS allows the differentiation between hypo- vs. hyperenhancing pancreatic solid lesions, with a considerable diagnostic accuracy, a fundamental step in the precise diagnosis of pancreatic tumors.

scholarly journals Accuracy of CBCT Linear Measurements to Determine the Height of Alveolar Crest to the Mental Foramen

2021 ◽  
Vol 13 (1) ◽  
pp. 1-5
Author(s):  
Mahnaz Sheikhi ◽  
Seyed Ali Saleh Gholami ◽  
Maryam Ghazizadeh
Keyword(s):  
Dental Implant ◽  
Gold Standard ◽  
Imaging Techniques ◽  
Preoperative Evaluation ◽  
Mental Foramen ◽  
Detailed Knowledge ◽  
Slice Thickness ◽  
Cross Sectional ◽  
Implant Placement ◽  
Alveolar Crest

Background: Detailed knowledge of the three-dimensional (3D) anatomical structures in precise treatment planning prior to implant placement is necessary. The choice of imaging techniques plays an important role in achieving the required information to measure exact dimensions. Cone beam computed tomography (CBCT) has increasingly been used for diagnosis and treatment in the fields of periodontology, endodontic, and orthodontics. It is also used as the preoperative evaluation of patients who are candidates for dental implant treatment. Dental implant placement is an important application of CBCT in dentistry. One of the features of CBCT is the possibility of changing the slice thickness while reviewing images. In this study, we examined the linear measurement accuracy of CBCT for determining the height of alveolar crest to the mental foramen in cross-sectional view with different slice thicknesses and in tangential view. Methods: We used five dry human mandibles in this study. Then the distance from the highest tip of alveolar crest to the upper border of mental foramen was measured by digital caliper (as gold standard) and on CBCT images in cross sectional view with 1, 3, 5, 7 and 9 mm slice thicknesses and in tangential view. Data were analyzed using IBM SPSS Statistics software version 22, paired t test, and inter class correlation. Results: Data were collected by evaluation of 5 dry mandible and 240 measurements. There were significant differences only in tangential view and 1 mm slice thickness option in cross-sectional view with the gold standard (P=0.003 and P=0.018 respectively). The results did not show any differences between the observers (P<0.001). Conclusions: Our results indicated that cross-sectional view is more accurate than tangential view, and 3 and 5 mm slice thicknesses are preferred for measurement.

scholarly journals Direct Imaging of Exoplanets Living an Exciting Life

2015 ◽  
Vol 10 (S314) ◽  
pp. 213-219
Author(s):  
G. Chauvin
Keyword(s):  
Physical Properties ◽  
Imaging Techniques ◽  
Formation Mechanisms ◽  
Contrast Imaging ◽  
The Past ◽  
High Contrast Imaging ◽  
Nearby Stars ◽  
Formation And Evolution ◽  
Observing Techniques

AbstractWith the development of high contrast imaging techniques and instruments, vast efforts have been devoted during the past decades to detect and characterize lighter, cooler and closer companions to nearby stars, and ultimately image new planetary systems. Complementary to other planet-hunting techniques, this approach has opened a new astrophysical window to study the physical properties and the formation mechanisms of brown dwarfs and planets. In this review, I will briefly describe the different observing techniques and strategies used, the main samples of targeted nearby stars, finally the main results obtained so far about exoplanet discoveries characterization of their physical properties, and study of their occurrence and possible formation and evolution mechanisms.

scholarly journals Differentiation of fibrotic and inflammatory component of Crohn’s disease-associated strictures

2020 ◽  
Vol 18 (2) ◽  
pp. 144-150 ◽  
Author(s):  
Jordi Rimola ◽  
Nunzia Capozzi
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Imaging Techniques ◽  
Balloon Dilation ◽  
Short Review ◽  
Cross Sectional ◽  
Cross Sectional Imaging ◽  
Sectional Imaging ◽  
Inflammatory Component

Patients with Crohn’s disease (CD) commonly develop bowel strictures, which may contain various degrees of inflammation and fibrosis. While predominantly inflammatory strictures may benefit from a medical anti-inflammatory treatment approach, fibrotic strictures would require endoscopic balloon dilation or surgery. Cross-sectional imaging surpasses endoscopy for characterization of stenotic segments and potentially may contribute to the optimal clinical management of these patients. This short review aims to discuss the potentialities and limitations of cross-sectional imaging techniques for assessing bowel fibrosis in patients with CD.

Application of Topological Sensitivity Toward Soft-Tissue Characterization From Vibroacoustography Measurements

2013 ◽  
Vol 8 (3) ◽  
Author(s):  
Huina Yuan ◽  
Bojan B. Guzina ◽  
Shigao Chen ◽  
Randall Kinnick ◽  
Mostafa Fatemi
Keyword(s):  
Tissue Characterization ◽  
Soft Tissues ◽  
Imaging Techniques ◽  
Imaging Method ◽  
Topological Sensitivity ◽  
Vibration Data ◽  
Viscoelastic Parameters ◽  
Resolution Imaging ◽  
Lesion Characterization

This study concerns the development and preliminary experimental verification of a topological sensitivity–based platform for the material characterization of tissue anomalies exposed by vibroacoustography-type imaging techniques. Vibroacoustography (VA) is a high-resolution imaging method that has been applied to the detection of pathological changes in soft tissues. Although the data provided by this method is related to the mechanical properties of tissue, the viscoelastic parameters of the object cannot be estimated by this imaging method itself. Topological sensitivity (TS) method is a data processing methodology that can be used to estimate the viscoelastic parameters of an object from vibration data. In this study, the concept of topological sensitivity is applied to interpret the vibroacoustography measurements for the purpose of lesion characterization. In the proposed approach, the topological sensitivity function, which signifies the variation of a given cost functional when an infinitesimal inclusion with trial material parameters is placed at the location of a point force, is formulated in terms of the adjoint field. The effectiveness of the resulting formula as a material indicator for lesion characterization is demonstrated by estimating the relative elastic parameters of a well-controlled neoprene sphere embedded in a tissue-mimicking phantom specimen.

scholarly journals The use of SPHARM-PDM and mean latitude axis to evaluate airway changes

2016 ◽  
Vol 86 (6) ◽  
pp. 943-948 ◽  
Author(s):  
Tung Nguyen ◽  
Ceib Phillips ◽  
Beatriz Paniagua
Keyword(s):  
Shape Change ◽  
Imaging Techniques ◽  
Cross Sectional Area ◽  
Cone Beam ◽  
Imaging Method ◽  
Sectional Area ◽  
Volume Changes ◽  
Cross Sectional ◽  
Pharyngeal Airway ◽  
Bilateral Sagittal Split Osteotomy

ABSTRACT Objective: To introduce new 3-D imaging techniques to characterize shape and volume changes of the oropharyngeal space after bilateral sagittal split osteotomy (BSSO) advancement. Materials and Methods: Longitudinal cone-beam computed tomography (CBCT) scans were obtained for 20 patients undergoing BSSO advancement at three time points (T1 = presurgery, T2 = splint removal, and T3 = 1 year after surgery). Segmentation of the airway was performed using the following boundaries: hard palate/posterior nasal spine superiorly and lower border of C3 to the base of the epiglottis inferiorly. For shape measurements, point-based correspondent models and mean latitude axis were obtained for all the data using SPHARM-PDM software. All 3-D correspondent models were rigidly registered using Procrustes alignment. Absolute distance maps and corresponding vector maps were calculated to show shape and vector differences between each correspondent point. Mean latitude axis is a new imaging method to calculate minimum cross-sectional areas along the long axis of the airway independent of head position/alignment. Results: The airway volume increased (P &lt; .01) after BSSO advancement (2973.9 mm3 ± 27882.0) and was stable (−439.9 mm3 ± 3308.8) 1 year post-op. 3-D color maps and semitransparency overlays showed more lateral than anteroposterior expansion of the airway after BSSO advancement. Mean latitude axis was used to measure minimum cross-sectional area, showing a statistically significant increase (52.7 mm2 ± 46.7) (P &lt; .01) after surgery and remained stable (−10.3 mm2 ± 43.3) 1 year after surgery. Conclusions: SPHARM-PDM and mean latitude axis are useful tools to assess airway shape change. BSSO advancement produces a significant increase in pharyngeal airway volume and minimum cross-sectional area. The airway space increased more transversely than anteroposteriorly.

Characterization of Dislocation Contrast in deformed steels with BCC structure by Electron Channeling Contrast Imaging Method

2012 ◽  
Vol 18 (S2) ◽  
pp. 688-689
Author(s):  
M. Sugiyama ◽  
G. Shigesato ◽  
Y. Shinohara
Keyword(s):  
Imaging Method ◽  
Contrast Imaging ◽  
Electron Channeling ◽  
Bcc Structure

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

scholarly journals Contrast-Enhanced Harmonic Endoscopic Ultrasonography in Pancreatic Diseases

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Can Xu ◽  
Zhaoshen Li ◽  
Michael Wallace
Keyword(s):  
Endoscopic Ultrasonography ◽  
Pancreatic Tumors ◽  
Imaging Method ◽  
Pancreatic Diseases ◽  
Pancreatic Cancers ◽  
Novel Technology ◽  
Contrast Enhanced ◽  
Pancreatic Masses ◽  
Adequate Sampling ◽  
Solid Lesions

Endoscopic ultrasonography (EUS) is the most sensitive imaging method for diagnosis of pancreatic tumors. However, it still has limits in the differentiation between pancreatic cancers and inflammatory tumor-like masses. A novel technology, contrast-enhanced harmonic EUS (CH-EUS), has been developed recently. It can visualize both parenchymal perfusion and microvasculature in pancreas without Doppler-related artifacts. Therefore, it is superior to EUS and CT in detecting small pancreatic masses and differential diagnosis of pancreatic masses. CH-EUS could be used for adequate sampling of pancreatic tumors and may predict the pathological features of the pancreatic solid lesions but still cannot replace EUS-FNA now.

scholarly journals Potential value of EUS in pancreatic surveillance of VHL patients

2016 ◽  
Vol 174 (5) ◽  
pp. 611-620 ◽  
Author(s):  
Sophie J van Asselt ◽  
Adrienne H Brouwers ◽  
Hendrik M van Dullemen ◽  
Eric J van der Jagt ◽  
Alfons H Bongaerts ◽  
...  
Keyword(s):  
Early Detection ◽  
Imaging Techniques ◽  
Medical Center ◽  
Somatostatin Receptor ◽  
Tertiary Care ◽  
Screening Method ◽  
Pancreatic Cysts ◽  
Cross Sectional ◽  
Solid Lesions ◽  
Vhl Disease

Background Patients with von Hippel-Lindau (VHL) disease are prone to develop pancreatic neuroendocrine tumors (pNETs). However, the best imaging technique for early detection of pNETs in VHL is currently unknown. In a head-to-head comparison, we evaluated endoscopic ultrasound (EUS) and 11C-5-hydroxytryptophan positron emission tomography (11C-5-HTP PET) compared with conventional screening techniques for early detection of pancreatic solid lesions in VHL patients. Methods We conducted a cross-sectional, prospective study in 22 patients at a tertiary care university medical center. Patients with VHL mutation or with one VHL manifestation and a mutation carrier as first-degree family member, with recent screening by abdominal computed tomography (CT) or magnetic resonance imaging (MRI) and somatostatin receptor scintigraphy (SRS), were eligible. Patients underwent EUS by linear Pentax echoendoscope and Hitachi EUB-525, and 11C-5-HTP PET. Patient-based and lesion-based positivity for pancreatic solid lesions were calculated for all imaging techniques with a composite reference standard. Results In 10 of the 22 patients, 20 pancreatic solid lesions were detected: 17 with EUS (P < 0.05 vs CT/MRI+ SRS), 3 with 11C-5-HTP PET, 3 with SRS, 9 with CT/MRI, and 9 with CT/MRI + SRS. EUS evaluations showed solid lesions with a median size of 9.7 mm (range 2.9–55 mm) and most of them were homogeneous, hypoechoic, isoelastic, and hypervascular. Moreover, EUS detected multiple pancreatic cysts in 18 patients with a median of 4 cysts (range 1–30). Conclusions EUS is superior to CT/MRI + SRS for detecting pancreatic solid lesions in VHL disease.11C-5-HTP PET has no value as a screening method in this setting. EUS performs well in early detection of pNETs, but its role in VHL surveillance is unclear.

Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

1991 ◽  
Vol 49 ◽  
pp. 762-763
Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea
Keyword(s):  
Magnetic Recording ◽  
Electron Probe ◽  
Microstructural Characterization ◽  
Crystallographic Structure ◽  
Recording Media ◽  
Layer By Layer ◽  
Cross Sectional ◽  
New Techniques ◽  
Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

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