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Contrast agents are sometimes used in CT scans of the chest to accentuate or enhance the differences in radiopacity between vascularized and less vascularized structures, but a standard chest CT scan is usually non-contrasted (i.e. "plain") and relies on different algorithms to produce various series of digitalized images known as view or "window".
A CT pulmonary angiogram, in this case showing pulmonary embolism of saddle-type, which becomes more radiolucent than the radiocontrast filled blood surrounding it (but it may be indistinguishable without radiocontrast). Contrast CT, or contrast-enhanced computed tomography (CECT), is X-ray computed tomography (CT) using radiocontrast.
An intravenous cannula is required for the administration of iodinated contrast. The typical dose is 30-40 g of iodine (corresponding to 20–30 cc of 370 mg/ml iodine solution). [10] However, for patients at high risk of contrast-induced nephropathy, it is possible to reduce the required amount of contrast using dual energy CT.
Low-dose high-resolution (1.25 mm) chest CT. HRCT is performed using a conventional CT scanner. However, imaging parameters are chosen so as to maximize spatial resolution: [1] a narrow slice width is used (usually 1–2 mm), a high spatial resolution image reconstruction algorithm is used, field of view is minimized, so as to minimize the size of each pixel, and other scan factors (e.g. focal ...
The 2021 U.S. Preventive Services Task Force guidelines recommend annual screening for lung cancer with low-dose computed tomography in adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years. [6]
Cardiac CT (CCT) is a modified form of the traditional chest CT due to the difficulty of imaging the complex, moving heart. [16] This is achieved through the use of thin slices and high-resolution scanning, as well as the addition of electrocardiogram (ECG) gating or triggering to capture a motion-free image.
4DCT has started to be used for diagnostic radiology procedures, for example looking at joint problems, the cardiac cycle and parathyroid washout of contrast. Downsides of 4DCT for diagnostic purposes include large and complex datasets, and increased radiation dose to the patient. [11]
As with any test that screens for disease, the risks of full-body CT scans need to be weighed against the benefit of identifying a treatable disease at an early stage. [6] An alternative to a full-body CT scan may be Magnetic resonance imaging (MRI) scans. MRI scans are generally more expensive than CT but do not expose the patient to ionizing ...