THE EFFECT OF COMPUTED TOMOGRAPHY CURRENT REDUCTION ON PROXIMAL FEMUR SUBJECT-SPECIFIC FINITE ELEMENT MODELS

2017 ◽  
Vol 17 (01) ◽  
pp. 1750012 ◽  
Author(s):  
CRISTINA FALCINELLI ◽  
ENRICO SCHILEO ◽  
FABIO BARUFFALDI ◽  
LUCA CRISTOFOLINI ◽  
FULVIA TADDEI
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Soft Tissues ◽  
Ct Scans ◽  
Human Cadaver ◽  
Biomechanical Models ◽  
Tube Current ◽  
Subject Specific ◽  
Fresh Frozen ◽  
Current Reduction

Many studies have addressed the modulation of computed tomography (CT) parameters, and particularly of tube current, to obtain a good compromise between the X-ray dose to the patient and the image quality for diagnostic applications. This study aimed at evaluating the influence of dose reduction by means of tube current reduction on the CT-based subject-specific finite element (FE) modeling. To this aim, CT scans at stepwise reduced values of tube current from 180[Formula: see text]mAs to 80[Formula: see text]mAs were performed on: (i) a densitometric phantom, to quantify the changes in the calibration equation; (ii) a fresh-frozen, water submersed, human cadaver femur, to quantify changes in geometry reconstruction and material mapping from CT, as well as strain prediction accuracy, based on the in vitro strain measurements available; (iii) a fresh-frozen human cadaver thigh with soft tissues attached, to quantify FE results changes in conditions similar to those found in vivo. The results showed that the tube current reduction does not affect the 3D modeling and the femur FE analysis. Our pilot study highlights the possibility of performing CT scans with reduced dose to generate biomechanical models, although a confirmation by performing larger studies with clinical CT data is needed.

scholarly journals Paraspinal Fat Stranding as an Unexpected Finding on Body Computed Tomography: A Key to Early Detection of Spinal Osteomyelitis

2020 ◽  
Vol 10 ◽  
pp. 6
Author(s):  
Eric L. Chen ◽  
Michael Rosenberg ◽  
Nitu Saran ◽  
Burce Ozgen ◽  
Karen Xie ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Early Detection ◽  
Soft Tissues ◽  
Ct Scans ◽  
Unexpected Finding ◽  
Reactive Protein ◽  
Spinal Osteomyelitis ◽  
Clinically Significant ◽  
Fat Stranding ◽  
Body Ct

Objective: At present, early detection of spinal osteomyelitis is a challenge. Patients may present with non-specific symptoms and diagnostic imaging studies may be obtained for seemingly unrelated complaints. Paraspinal fat stranding on body computed tomography (CT) as a sign of osteomyelitis is easily overlooked and has not been reported in the literature to our knowledge. The purpose of this study is to review findings on body CT that points to unsuspected spinal osteomyelitis. Material and Methods: A retrospective review of patients with spinal osteomyelitis who also had concomitant chest, abdominal, or pelvic CT scans between August 2013 and February 2017 yielded 10 patients who had confirmed osteomyelitis (ages between 51 and 75, mean age 64.8). Images and medical records were reviewed. Results: The age of the patients ranged from 51 to 75 years (median value, 64). All patients had multiple underlying medical illnesses, and half of them had a known preceding infection such as sepsis or urinary tract infection. At presentation, three patients had a fever and two patients had neurologic deficits. Seven out of eight patients had elevated C-reactive protein and erythrocyte sedimentation rate, five patients had leukocytosis, and four patients had positive blood cultures. Paravertebral fat stranding and endplate erosions were observed in 9 and 6 cases, respectively, on initial body CT for unrelated indications, and subsequent magnetic resonance imaging confirmed osteomyelitis discitis. Conclusion: Clinically significant, but initially unsuspected, spinal pathology such as osteomyelitis may present on body CT scans. Earlier diagnosis of spinal osteomyelitis can be made by performing a focused evaluation of the paraspinal soft tissues and including osteomyelitis in the differential diagnosis, particularly in high-risk patients.

scholarly journals Quantitative Computed Tomography Protocols Affect Material Mapping and Quantitative Computed Tomography-Based Finite-Element Analysis Predicted Stiffness

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Hugo Giambini ◽  
Dan Dragomir-Daescu ◽  
Ahmad Nassr ◽  
Michael J. Yaszemski ◽  
Chunfeng Zhao
Keyword(s):  
Computed Tomography ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Risk ◽  
Quantitative Computed Tomography ◽  
Image Data ◽  
Element Analysis ◽  
Calibration Phantom ◽  
Fresh Frozen ◽  
Experimental Values

Quantitative computed tomography-based finite-element analysis (QCT/FEA) has become increasingly popular in an attempt to understand and possibly reduce vertebral fracture risk. It is known that scanning acquisition settings affect Hounsfield units (HU) of the CT voxels. Material properties assignments in QCT/FEA, relating HU to Young's modulus, are performed by applying empirical equations. The purpose of this study was to evaluate the effect of QCT scanning protocols on predicted stiffness values from finite-element models. One fresh frozen cadaveric torso and a QCT calibration phantom were scanned six times varying voltage and current and reconstructed to obtain a total of 12 sets of images. Five vertebrae from the torso were experimentally tested to obtain stiffness values. QCT/FEA models of the five vertebrae were developed for the 12 image data resulting in a total of 60 models. Predicted stiffness was compared to the experimental values. The highest percent difference in stiffness was approximately 480% (80 kVp, 110 mAs, U70), while the lowest outcome was ∼1% (80 kVp, 110 mAs, U30). There was a clear distinction between reconstruction kernels in predicted outcomes, whereas voltage did not present a clear influence on results. The potential of QCT/FEA as an improvement to conventional fracture risk prediction tools is well established. However, it is important to establish research protocols that can lead to results that can be translated to the clinical setting.

Individualized kV Selection and Tube Current Reduction in Excretory Phase Computed Tomography Urography

2013 ◽  
Vol 37 (4) ◽  
pp. 551-559 ◽  
Author(s):  
Adam T. Froemming ◽  
Akira Kawashima ◽  
Naoki Takahashi ◽  
Robert P. Hartman ◽  
Mark A. Nathan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Computed Tomography Urography ◽  
Tube Current ◽  
Current Reduction

The Effect of Varying the Density-Modulus Relationship Used to Apply Material Properties in a Finite Element Model of the Distal Ulna

2008 ◽  
Author(s):  
Rebecca L. Austman ◽  
Jaques S. Milner ◽  
David W. Holdsworth ◽  
Cynthia A. Dunning
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Material Properties ◽  
Cost Effective ◽  
Element Model ◽  
Implant Design ◽  
Timely Manner ◽  
Distal Ulna ◽  
Subject Specific

In many areas of orthopaedic biomechanics, such as implant design, properly developed Finite Element (FE) models can be a great companion to in-vitro studies, as they may allow a wider range of experimental variables to be explored in a cost-effective and timely manner. One challenge in developing these models is the assignment of accurate material properties to bone. Through the use of computed tomography (CT), many recent studies have developed subject-specific FE models, where material properties of bone are assigned based on density information derived from the scans. This involves the use of an equation to relate density and elastic modulus. There are several such relationships from which to choose in the literature. Most FE studies tend to use one of these multiple equations without justification or investigation into its appropriateness for the model.

SPECIFIC CHARACTERISTICS OF BONE STRUCTURES ON CT-SCANS OF PATIENTS WITH SINONASAL INVERTED PAPILLOMAS

2019 ◽  
Vol 65 (4) ◽  
pp. 590-595
Author(s):  
Arkadiy Naumenko ◽  
Kseniya Sapova ◽  
Oleg Konoplev ◽  
Svetlana Astashchenko ◽  
Igor Chernushevich
Keyword(s):  
Computed Tomography ◽  
Tumor Recurrence ◽  
Inverted Papilloma ◽  
Ct Scans ◽  
Precise Localization ◽  
Sinonasal Inverted Papilloma ◽  
Bone Structures ◽  
Inverted Papillomas

Precise localization and excision of the originating site of a sinonasal inverted papilloma is essential for decreasing tumor recurrence. In this study we evaluated the use of preoperative computed tomography (CT) to pinpoint the attachment/origi-nating sites of the tumor.

scholarly journals Metacarpal Bony Dimensions Related to Headless Compression Screw Sizes

2019 ◽  
Vol 12 (S 01) ◽  
pp. S39-S44
Author(s):  
Michael Okoli ◽  
Kevin Lutsky ◽  
Michael Rivlin ◽  
Brian Katt ◽  
Pedro Beredjiklian
Keyword(s):  
Computed Tomography ◽  
Fracture Fixation ◽  
Ct Scans ◽  
Compression Screw ◽  
Metacarpal Head ◽  
Headless Compression Screw ◽  
Metacarpal Bones ◽  
Headless Compression Screws ◽  
The Mean ◽  
Distal Aspect

Abstract Introduction The purpose of this study is to determine the radiographic dimensions of the finger metacarpals and to compare these measurements with headless compression screws commonly used for fracture fixation. Materials and Methods We analyzed computed tomography (CT) scans of the index, long, ring, and small metacarpal bones and measured the metacarpal length, distance from the isthmus to the metacarpal head, and intramedullary diameter of the isthmus. Metacarpals with previous fractures or hardware were excluded. We compared these dimensions with the size of several commercially available headless screws used for intramedullary fixation. Results A total of 223 metacarpals from 57 patients were analyzed. The index metacarpal was the longest, averaging 67.6 mm in length. The mean distance from the most distal aspect of the metacarpal head to the isthmus was 40.3, 39.5, 34.4, and 31 mm for the index, long, ring, and small metacarpals, respectively. The narrowest diameter of the isthmus was a mean of 2.6, 2.7, 2.3, and 3 mm for the index, long, ring, and small metacarpals, respectively. Of 33 commercially available screws, only 27% percent reached the isthmus of the index metacarpal followed by 42, 48, and 58% in the long, ring, and small metacarpals, respectively. Conclusion The index and long metacarpals are at a particular risk of screw mismatch given their relatively long lengths and narrow isthmus diameters.

scholarly journals Cross-sectional anatomy, computed tomography, and magnetic resonance imaging of the banded houndshark (Triakis scyllium)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sang Wha Kim ◽  
Adams Hei Long Yuen ◽  
Cherry Tsz Ching Poon ◽  
Joon Oh Hwang ◽  
Chang Jun Lee ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Soft Tissues ◽  
Imaging Techniques ◽  
Evolutionary Developmental Biology ◽  
Phylogenetic Position ◽  
Ct Scanner ◽  
Resonance Imaging ◽  
Cross Sectional

AbstractDue to their important phylogenetic position among extant vertebrates, sharks are an invaluable group in evolutionary developmental biology studies. A thorough understanding of shark anatomy is essential to facilitate these studies and documentation of this iconic taxon. With the increasing availability of cross-sectional imaging techniques, the complicated anatomy of both cartilaginous and soft tissues can be analyzed non-invasively, quickly, and accurately. The aim of this study is to provide a detailed anatomical description of the normal banded houndshark (Triakis scyllium) using computed tomography (CT) and magnetic resonance imaging (MRI) along with cryosection images. Three banded houndsharks were scanned using a 64-detector row spiral CT scanner and a 3 T MRI scanner. All images were digitally stored and assessed using open-source Digital Imaging and Communications in Medicine viewer software in the transverse, sagittal, and dorsal dimensions. The banded houndshark cadavers were then cryosectioned at approximately 1-cm intervals. Corresponding transverse cryosection images were chosen to identify the best anatomical correlations for transverse CT and MRI images. The resulting images provided excellent detail of the major anatomical structures of the banded houndshark. The illustrations in the present study could be considered as a useful reference for interpretation of normal and pathological imaging studies of sharks.

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