Gastrointestinal tract and salivary glands
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha in Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
The procedure for sialography requires the following equipment (Fig. 5.2b): The full range of Rabinov sialography catheters ranging from 0.012 to 0.032 inches (Fig. 5.2a). The larger calibre is usually reserved for Stenson’s duct, but the full range of catheters are often employed in patients with a reduced opening as a result of chronic infection. A full set of lacrimal dilators, which range from 0000 to 0 calibre.A 5 ml or 10 ml disposable syringe.Lemon concentrate.A mobile high intensity light.Iodinated contrast agent.Magnifying loops.Dental cotton rolls and dental swabs.
Imaging techniques, including computed tomography-guided biopsy and fluorodeoxyglucose-positron emission tomography
John Dudley Langdon, Mohan Francis Patel, Robert Andrew Ord, Peter Brennan in Operative Oral and Maxillofacial Surgery, 2017
CT is an imaging modality which is rapid and widely available. A CT scanner consists of an x-ray tube which sends a fan of x-rays through the patient and the attenuation of the beam by the patient is detected. The process is repeated as the tube and detectors rotate and the patient is advanced through the scanner. The degree of x-ray absorption by each volume of tissue (voxel) is displayed as a pixel which is allocated a number (Hounsfield unit) (Table 1.2). This information may be digitally manipulated so as to best demonstrate the tissues of interest (e.g. by changing the range of ‘numbers’ in the grey scale or ‘window width’ or by using algorithms to alter the ‘sharpness’ of the image). The same information may be used to provide multiplanar reformats or rendering of three-dimensional (3D) objects to facilitate visual assessment. Imaging of soft tissues generally requires the administration of iodinated contrast medium to enhance pathological tissues and help delineate vascular structures from other soft tissue such as lymph nodes. Artefact from metallic materials such as dental restoration may markedly degrade imaging of the face due to ‘beam-hardening artefact’; however, there are methods to reduce this, such as specific angling of the scan plane or the use of specific image reconstruction techniques. The availability of CT fluoroscopy and ‘in room’ CT controls/moni- tors has improved the safety and efficacy of CT-guided biopsies of deep facial and skull base lesions (Figure 1.3).
Imaging of the Neck
John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford in Head & Neck Surgery Plastic Surgery, 2018
CT is used extensively in staging head and neck cancer patients and for detecting masses or abscesses in the deep spaces of the neck. With the advent of multi-detector scanners, the entire neck can be scanned in a few seconds and a volumetric data set obtained, allowing reconstructions in any plane. Because of its relatively low soft-tissue resolution, intravenous iodinated contrast agents are necessary. Dual-source scanning is the latest breakthrough in CT technology and early results are promising for imaging the neck.4 Radiation dose is an important consideration on CT and dose reduction can be achieved by special in-built features in most modern CT scanners as well as manually altering settings such as mAs and KV, without affecting diagnostic image quality.5, 6 Artefact from dental amalgam can be negated by gantry tilt but the combination of this facility and volumetric scanning is not available on all scanners.7 Cone-beam CT has an evolving role in head and neck imaging.8
Quantification of DNA damage in patients undergoing non-contrast and contrast enhanced whole body PET/CT investigations using comet assay and micronucleus assay
Published in International Journal of Radiation Biology, 2019
Amit Nautiyal, Tanmoy Mondal, Anirban Mukherjee, Deepanjan Mitra, Aruna Kaushik, Harish Chandra Goel, Alpana Goel, Subrata Kumar Dey
A number of studies have been performed on X-ray and CT scans in patients that show that iodinated contrast media enhances DNA damage during these procedures (Piechowiak et al. 2015; Wang et al. 2017). Iodinated contrast media is mainly used in diagnostic investigations to enhance contrast of organs or fluids within the body. Recently there is an increase in the trend of performing contrast-enhanced computed tomography (CECT) as an adjunct to PET for better delineation of anatomy. It obviates the need of performing separate CECT in the same patient and thereby reducing radiation dose and cost to the patient. In case of PET/CT investigations, the cells are irradiated not only by 120 kV X-ray photons externally but also by 511 keV annihilation photons and high energy positrons internally. However, the extent of DNA damage during a PET/CT scan has not been reported so far.
Diagnosis of coronary artery disease: potential complications of imaging techniques
Published in Acta Cardiologica, 2022
Evangelos Sdogkos, Andrew Xanthopoulos, Grigorios Giamouzis, John Skoularigis, Filippos Triposkiadis, Ioannis Vogiatzis
The use of iodinated contrast media in imaging examinations is a factor for the occurrence of complications, which are referred to as Radiographic Contrast Reactions [3]. They include Hypersensitivity Reactions, Contrast-Induced Thyroid Dysfunction, and Contrast-induced Acute Kidney Injury (CI-AKI) [4]. They can occur (especially the latter) not only during ICA but also during Coronary Computed Tomography Angiography (CCTA). Common definitions for CI-AKI include an absolute rise in serum creatinine ≥0.5 mg/dL, or a relative increase of ≥25% at 48–72 h after contrast exposure, while the typical timeline for a decline in renal function is 2–5 days after iodinated contrast exposure. Risk factors associated with the patient’s unfavourable prognosis are ST-elevation myocardial infarction, cardiogenic shock, pre-existent renal disease, and the administrated contrast volume. Those patients need closer monitoring and care in order not to progress to the stage of chronic nephropathy. CI-AKI is demonstrated to be the third most common cause of renal injury among hospitalised patients, and its incidence varies at about 2–25% [5].
Performance of computed tomography and its reliability for the diagnosis of transmural gastrointestional necrosis in a setting of acute ingestion of predominantly strong acid substances in adults
Published in Clinical Toxicology, 2023
Rathachai Kaewlai, Napakadol Noppakunsomboon, Sasima Tongsai, Bandana Tamrakar, Nutnaree Kumthong, Wanwarang Teerasamit, Napaporn Kongkaewpaisan, Arin Pisanuwongse, Ramida Amornsitthiwat, Worapat Maitriwong, Chanikarn Khanutwong, Piyaporn Apisarnthanarak
The CT examinations were performed on the hospital’s multidetector CT scanners. There were two 64-slice scanners (LightSpeed VCT and Discovery CT750 HD, both from GE Healthcare) and two 256-slice scanners (Revolution CT, GE Healthcare). Axial scans were performed with a 1.25-mm slice thickness in an unenhanced phase of the chest, abdomen, and pelvis. This was followed by the intravenous administration of nonionic iodinated contrast media (300–370 mg of iodine/mL; 1.5–2.0 mL/kg) at 2–4 mL/s via injectors. Oral or rectal contrast media were not used. Postcontrast scans of the chest portion were performed in the late arterial phase (approximately 35 s after contrast administration). For the abdomen/pelvis portion, these procedures were performed in a portovenous phase (approximately 80 s after contrast administration). The chest scan parameters were 120 kVp and 250 mAs for the 64-multidetector CT systems and 180 mAs for the 256- multidetector CT systems. The abdominal-pelvic scan parameters were 120 kVp and 300 mAs for the 64-multidetector CT systems and 250 mAs for the 256-multidetector CT systems. Images were sent to a Picture Archiving and Communication System (Synapse, FujiFilm Corporation).
Related Knowledge Centers
- Hounsfield Scale
- Iodine
- Urinary System
- Cancer
- Uterus
- Radiography
- Radiocontrast Agent
- Radiodensity
- X-Ray Tube
- CT Scan