Neuroimaging

2021 ◽  
pp. 283-291
Author(s):  
Dong Kun Kim ◽  
David F. Black
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Initial Evaluation ◽  
Cross Sectional ◽  
Acute Trauma ◽  
Neurologic Symptoms ◽  
Safety Issues ◽  
Diagnosis And Prognosis ◽  
Therapeutic Decisions ◽  
Tissue Contrast

Neuroimaging is commonly used in the clinical setting to aid in determining a diagnosis and prognosis and in making therapeutic decisions. This chapter reviews indications, pitfalls, underlying physics, safety issues, and examples of select neuroimaging methods. Computed tomography (CT) is the most frequently used cross-sectional technique for the initial evaluation of a patient with acute neurologic symptoms because of its availability, speed, and reliability. CT is also invaluable for patients with acute trauma because of its high spatial resolution and bone–soft tissue contrast.

Computed tomography

2013 ◽  
pp. 521-530
Author(s):  
Geoff Hide ◽  
Jennifer Humphries
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
The Body ◽  
Whole Body ◽  
Cross Sectional ◽  
Ct Arthrography ◽  
Complex Image ◽  
Spine Ct ◽  
Tissue Contrast ◽  
Medical Radiation Exposure

Computed tomography (CT), along with its cross-sectional partner MRI, continues to evolve apace. Although MRI retains the larger role in the musculoskeletal system due to its unparalleled soft tissue contrast and, not least, its lack of ionizing radiation, CT offers significant advantages in many areas. Imaging acute trauma is more rapid with CT, allowing ‘whole body’ assessment of patients following polytrauma, and CT is more useful than MRI in demonstrating the configuration of fractures, aiding surgical planning. CT can clearly identify cortical bone and areas of calcification, making the diagnosis of tarsal coalitions straightforward and facilitating the diagnosis and characterization of bone tumours such as osteoid osteoma and chondroid lesions. CT arthrography supplements standard imaging with intra-articular contrast to allow the detection of subtle joint abnormalities, and CT can demonstrate needles precisely within bone and soft tissue to enable the performance of complex image-guided procedures. Developments in CT have been especially rapid in the past decade and although this has particularly impacted on cardiac imaging, other areas of medicine, including rheumatology, have benefited. High multislice scanners can obtain data for a volume of tissue allowing reconstruction of slices with exceptional detail in any plane, and can rapidly image large areas of the body such as the spine. CT is responsible for a large proportion of the population’s medical radiation exposure. Although techniques allowing reduction in dose continue to advance, radiologists and referrers retain responsibility to ensure that requests for CT examinations are necessary and justifiable.

Computed tomography

2013 ◽  
Author(s):  
Geoff Hide ◽  
Jennifer Humphries
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
The Body ◽  
Whole Body ◽  
Cross Sectional ◽  
Ct Arthrography ◽  
Complex Image ◽  
Spine Ct ◽  
Tissue Contrast ◽  
Medical Radiation Exposure

Computed tomography (CT), along with its cross-sectional partner MRI, continues to evolve apace. Although MRI retains the larger role in the musculoskeletal system due to its unparalleled soft tissue contrast and, not least, its lack of ionizing radiation, CT offers significant advantages in many areas. Imaging acute trauma is more rapid with CT, allowing 'whole body' assessment of patients following polytrauma, and CT is more useful than MRI in demonstrating the configuration of fractures, aiding surgical planning. CT can clearly identify cortical bone and areas of calcification, making the diagnosis of tarsal coalitions straightforward and facilitating the diagnosis and characterization of bone tumours such as osteoid osteoma and chondroid lesions. CT arthrography supplements standard imaging with intra-articular contrast to allow the detection of subtle joint abnormalities, and CT can demonstrate needles precisely within bone and soft tissue to enable the performance of complex image-guided procedures. Developments in CT have been especially rapid in the past decade and although this has particularly impacted on cardiac imaging, other areas of medicine, including rheumatology, have benefited. High multislice scanners can obtain data for a volume of tissue allowing reconstruction of slices with exceptional detail in any plane, and can rapidly image large areas of the body such as the spine. CT is responsible for a large proportion of the population's medical radiation exposure. Although techniques allowing reduction in dose continue to advance, radiologists and referrers retain responsibility to ensure that requests for CT examinations are necessary and justifiable.

scholarly journals Accuracy and Reproducibility of Facial Measurements of Digital Photographs and Wrapped Cone Beam Computed Tomography (CBCT) Photographs

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 757
Author(s):  
Maged Sultan Alhammadi ◽  
Abeer Abdulkareem Al-mashraqi ◽  
Rayid Hussain Alnami ◽  
Nawaf Mohammad Ashqar ◽  
Omar Hassan Alamir ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Cone Beam Computed Tomography ◽  
High Reliability ◽  
Three Dimensional ◽  
Cone Beam ◽  
Cross Sectional ◽  
Facial Profile ◽  
Digital Photographs ◽  
Gonial Angle

The study sought to assess whether the soft tissue facial profile measurements of direct Cone Beam Computed Tomography (CBCT) and wrapped CBCT images of non-standardized facial photographs are accurate compared to the standardized digital photographs. In this cross-sectional study, 60 patients with an age range of 18–30 years, who were indicated for CBCT, were enrolled. Two facial photographs were taken per patient: standardized and random (non-standardized). The non-standardized ones were wrapped with the CBCT images. The most used soft tissue facial profile landmarks/parameters (linear and angular) were measured on direct soft tissue three-dimensional (3D) images and on the photographs wrapped over the 3D-CBCT images, and then compared to the standardized photographs. The reliability analysis was performed using concordance correlation coefficients (CCC) and depicted graphically using Bland–Altman plots. Most of the linear and angular measurements showed high reliability (0.91 to 0.998). Nevertheless, four soft tissue measurements were unreliable; namely, posterior gonial angle (0.085 and 0.11 for wrapped and direct CBCT soft tissue, respectively), mandibular plane angle (0.006 and 0.0016 for wrapped and direct CBCT soft tissue, respectively), posterior facial height (0.63 and 0.62 for wrapped and direct CBCT soft tissue, respectively) and total soft tissue facial convexity (0.52 for both wrapped and direct CBCT soft tissue, respectively). The soft tissue facial profile measurements from either the direct 3D-CBCT images or the wrapped CBCT images of non-standardized frontal photographs were accurate, and can be used to analyze most of the soft tissue facial profile measurements.

scholarly journals Combined visualization of echinoderm hard and soft parts using contrast-enhanced micro-computed tomography

Zoosymposia ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 172-191 ◽  
Author(s):  
ALEXANDER ZIEGLER
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
3D Visualization ◽  
Soft Part ◽  
Three Dimensional ◽  
Ethanol Solution ◽  
Micro Computed Tomography ◽  
Soft Tissue Contrast ◽  
Contrast Enhanced ◽  
Tissue Contrast

Recent studies have shown that micro-computed tomography (µCT) must be considered one of the most suitable techniques for the non-invasive, three-dimensional (3D) visualization of metazoan hard parts. In addition, µCT can also be used to visualize soft part anatomy non-destructively and in 3D. In order to achieve soft tissue contrast using µCT based on X-ray attenuation, fixed specimens must be immersed in staining solutions that include heavy metals such as silver (Ag), molybdenum (Mo), osmium (Os), lead (Pb), or tungsten (W). However, while contrast-enhancement has been successfully applied to specimens pertaining to various higher metazoan taxa, echinoderms have thus far not been analyzed using this approach. In order to demonstrate that this group of marine invertebrates is suitable for contrast-enhanced µCT as well, the present study provides results from an application of this technique to representative species from all five extant higher echinoderm taxa. To achieve soft part contrast, freshly fixed and museum specimens were immersed in an ethanol solution containing phosphotungstic acid and then scanned using a high-resolution desktop µCT system. The acquired datasets show that the combined visualization of echinoderm soft and hard parts can be readily accomplished using contrast-enhanced µCT in all extant echinoderm taxa. The results are compared with µCT data obtained using unstained specimens, with conventional histological sections, and with data previously acquired using magnetic resonance imaging, a technique known to provide excellent soft tissue contrast despite certain limitations. The suitability for 3D visualization and modeling of datasets gathered using contrast-enhanced µCT is illustrated and applications of this novel approach in echinoderm research are discussed.

Radiography and ultrasound of the equine neck

UK-Vet Equine ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 142-149
Author(s):  
Jonathon J Dixon ◽  
Lucy Meehan
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Ultrasound Examination ◽  
Imaging Modality ◽  
Three Dimensional ◽  
Cross Sectional ◽  
Articular Process ◽  
Planar Images ◽  
Cross Sectional Imaging ◽  
Sectional Imaging

Diagnostic imaging of the equine neck is undertaken for a wide variety of conditions. In many cases, radiography is the principal imaging modality, often complemented by ultrasound examination. Common conditions encountered include osteoarthritis, articular process joint osteochondral fragmentation, cervical vertebral malformation (‘wobbler’), fractures and numerous soft tissue lesions. The complex three-dimensional anatomy of the region limits interpretation of planar images and, in some cases, cross-sectional imaging (such as computed tomography) may be required. However, careful use of radiography and ultrasound can help clinicians to achieve a diagnosis in many cases, often from combining conventional and lesion-orientated projections with a thorough clinical examination.

Image-guided radiation therapy using computed tomography in radiotherapy

2010 ◽  
Vol 10 (2) ◽  
pp. 121-136 ◽  
Author(s):  
Winky Wing Ki Fung ◽  
Vincent Wing Cheung Wu
Keyword(s):  
Computed Tomography ◽  
Radiation Therapy ◽  
Soft Tissue ◽  
Image Guidance ◽  
Cone Beam ◽  
Patient Specific ◽  
Image Guided Radiotherapy ◽  
Soft Tissue Contrast ◽  
Image Guided ◽  
Tissue Contrast

AbstractThe sharp dose gradients in intensity-modulated radiation therapy increase the treatment sensitivity to various inter- and intra-fractional uncertainties, in which a slight anatomical change may greatly alter the actual dose delivered. Image-guided radiotherapy refers to the use of advanced imaging techniques to precisely track and correct these patient-specific variations in routine treatment. It can also monitor organ changes during a radiotherapy course. Currently, image-guided radiotherapy using computed tomography has gained much popularity in radiotherapy verification as it provides volumetric images with soft-tissue contrast for on-line tracking of tumour. This article reviews four types of computed tomography-based image guidance systems and their working principles. The system characteristics and clinical applications of the helical, megavoltage, computed tomography, and kilovoltage, cone-beam, computed tomography systems are discussed, given that they are currently the most commonly used systems for radiotherapy verification. This article also focuses on the recent techniques of soft-tissue contrast enhancement, digital tomosynthesis, four-dimensional fluoroscopic image guidance, and kilovoltage/megavoltage, in-line cone-beam imaging. These evolving systems are expected to take over the conventional two-dimensional verification system in the near future and provide the basis for implementing adaptive radiotherapy.

scholarly journals Multislice Computed Tomography Assessment of Airway Patency Changes Associated with Mandibular Advancement Appliance Therapy in Supine Patients with Obstructive Sleep Apnea

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Matsumura ◽  
Hiroshi Ueda ◽  
Toshikazu Nagasaki ◽  
Cynthia Concepción Medina ◽  
Koji Iwai ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Multislice Computed Tomography ◽  
Upper Airway ◽  
Mandibular Advancement ◽  
Sectional Area ◽  
Cross Sectional ◽  
Soft Tissue Volume ◽  
Obstructive Sleep ◽  
Mandibular Advancement Appliance

The purpose of the present study was to measure the regional effects of the mandibular advancement appliance (MAA) on the upper airway of supine subjects with obstructive sleep apnea (OSA) using multislice computed tomography (MSCT). The subjects included 8 males and 5 females who were diagnosed with mild to moderate OSA and were referred to the Orthodontic Clinic of Hiroshima University Hospital, where they underwent MAA therapy. Using a CT scanner, baseline MSCT images were obtained from the subjects without the MAA for morphological analysis, and then the experimental images were obtained while wearing the MAA. To measure the anteroposterior diameter, width, and cross-sectional area of the oropharynx region of interest (ROI), five distance variables were first defined on each multiplanar reconstruction (MPR) image using OsiriX. Additionally, the volumes of the upper airway, bony hard tissue, and soft tissue (soft palate and tongue) in the oro-hypopharyngeal region were measured. In most of the assessed airway size variables, significant increases in the anteroposterior diameter and width were observed after MAA therapy. Regarding the upper airway cross-sectional area, all the upper airway size variables exhibited significant increases. In the volumetric analysis, a significant increase was observed in airway volume, whereas the soft tissue volume in the oro-hypopharyngeal region did not show the significant decrease after MMA therapy. However, from a different point of view, the volumes of the upper airway and soft tissue significantly increased and decreased, respectively, as demonstrated by the calculated ratio for the oro-hypopharyngeal region. We demonstrated that the proportional size of the soft tissue volume, i.e., the soft palate and tongue in the oro-hypopharyngeal region, significantly decreased during use of an MAA. This forward displacement of the soft tissue thereby increases the retroglossal airway space (except the nasopharynx) three-dimensionally.

scholarly journals Prevalence of soft tissue calcifications in CBCT images from the Oral and Maxillofacial Radiology Service at UNAB, Viña del Mar, Chile.

2020 ◽  
Vol 9 (6) ◽  
pp. 457-465
Author(s):  
Patricio Meléndez-Rojas ◽  
◽  
Leniz Arancibia-Mesas ◽  
Carolina Poblete-Carrasco ◽  
◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Cone Beam Computed Tomography ◽  
Soft Tissues ◽  
Cone Beam ◽  
Maxillofacial Radiology ◽  
Cross Sectional ◽  
Radiology Service ◽  
Computed Tomography Images ◽  
Oral And Maxillofacial Radiology

Soft tissue calcifications can indicate the presence of more serious, potentially life-threatening pathologies. Therefore, their study can lead to an early diagnosis of those conditions that have not yet become clinically apparent. Main objective: To determine the prevalence of calcifications in soft tissues of the head and neck in cone beam computed tomography images obtained from the Oral and Maxillofacial Radiology Service at Universidad Andrés Bello (UNAB), Viña del Mar, Chile. Material and Methods: Retrospective, cross-sectional, quantitative study. A total of 288 images of cone beam computed tomography (CBCT) were used. Images were obtained at random from the database of the Oral and Maxillofacial Radiology Service at UNAB, Viña Del Mar, between 2014 and 2019. Results: A prevalence of 59.72% of soft tissue calcifications was obtained. The most prevalent were: tonsilloliths and calcified stylohyoid ligament, accounting for 30.65% and 45.56%, respectively. Conclusion: A high prevalence of soft tissue calcifications was found in a population that has not been studied previously; therefore, it is important that the dentist perform a detailed analysis of the cone beam computed tomography.

scholarly journals Intraobserver and interobserver reliability of computed tomography measurements of the soft palate in French bulldogs

2019 ◽  
Vol 6 (1) ◽  
pp. e000373
Author(s):  
Pauline Deprez ◽  
Iban Irubetagoyena ◽  
Jean-Guillaume Grand ◽  
Nathaniel Harran
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Endotracheal Tube ◽  
Soft Palate ◽  
Sagittal Plane ◽  
Interobserver Reliability ◽  
Intraclass Correlation ◽  
Ct Image ◽  
Sectional Area ◽  
Cross Sectional

BackgroundCT imaging has been used to document the soft palate dimensions in brachycephalic dogs but reliability of such measurements has not been evaluated. The aims of this study were to propose a method of measurements of the soft palate in French bulldogs and determine its reliability.MethodsThirty French bulldogs were prospectively included. Five measurements of the soft palate were performed on soft tissue and bone window mid-sagittal images: length, thickness at 25, 50 and 75 per cent of its length and sagittal plane cross-sectional area. Three sets of data were separately acquired by three observers. Intraobserver and interobserver reliability for all measurements was assessed using intraclass correlation coefficient (ICC).ResultsThe median ICCs showed excellent reliability (0.90 to 0.99) for all intraobserver measurements except for thickness at 75 per cent which showed good (0.80 to 0.89) to excellent reliability. The median ICC showed excellent reliability for all interobserver measurements.ConclusionThe soft palate measurements on a single CT image are reproducible and repeatable. Further study is needed to assess the reliability of these measurements in the same patient with different endotracheal tube positions.

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