Question

What CT scanning mode may induce patient motion artifact from several stops and starts of the gantry table during data acquisition?

Answer 1

The step-and-shoot or sequential CT scanning mode induces patient motion artifact due to the gantry table stopping and starting for each image slice, whereas spiral or helical CT scanning provides continuous motion, reducing such artifacts.

Step-by-step explanation:

The CT scanning mode that may induce patient motion artifact from several stops and starts of the gantry table during data acquisition is a step-and-shoot or sequential CT scanning mode. In this mode, the gantry moves to a specific location, stops to acquire the image data, and then moves again to the next position, leading to the potential for motion artifacts if the patient moves during these stops. Modern CT scanners often use spiral or helical CT scanning, where the gantry and table move continuously, reducing the likelihood of such motion artifacts and providing more efficient data collection.

CT scans, or Computed Tomography scans, are imaging techniques that use x-ray radiation to create detailed cross-sectional images of the body. These images can then be computer processed to construct three-dimensional representations of the scanned area. The resolution of CT scans is typically very high, which is crucial in identifying various medical conditions and abnormalities.

Answer 2

The CT scanning mode that may induce patient motion artifact from several stops and starts of the gantery table during data acquisition is the step-and-shoot mode.

Step-by-step explanation:

In CT scanning, the step-and-shoot mode involves moving the patient through the scanner while the X-ray tube rotates around them. This mode is commonly used for examinations that require a higher resolution or for patients who cannot hold their breath for an extended period. However, this mode can also result in patient motion artifacts due to the multiple stops and starts of the gantry table during data acquisition.

During the step-and-shoot mode, the gantry table moves in discrete steps, stopping at each angular position to acquire a single projection image. This process can cause noticeable motion artifacts in patients who are unable to remain still during each stop. These artifacts can appear as blurring, streaking, or ghosting in the reconstructed images, making it difficult to accurately diagnose pathologies. To minimize patient motion artifacts in step-and-shoot CT scanning, several strategies can be employed. One approach is to use respiratory gating, which synchronizes the scanning process with the patient's breathing cycle to ensure that images are acquired during periods of minimal respiratory motion. Another strategy is to provide sedation or anesthesia to help patients remain still during the examination. Additionally, some CT scanners now offer adaptive statistical iterative reconstruction (ASIR) techniques that can help reduce motion artifacts by incorporating statistical models into image reconstruction algorithms.

In summary, while the step-and-shoot mode can provide high-resolution images, it is important to be aware of the potential for patient motion artifacts and take steps to minimize their impact on image quality. By employing strategies such as respiratory gating, sedation, and ASIR techniques, it is possible to reduce motion artifacts and improve diagnostic accuracy in CT scanning.