Improved Signalto Noise Ratio

By allowing images to be obtained from multiple detectors, MHCT can provide an improved signal-to-noise-ratio. MHCT allows this to happen during both data collection and postprocessing. During initial data collection, if one uses the same table speed and slice thickness as for single-detector helical CT scanning, the effective pitch is reduced to one-fourth of its former value, quadrupling the effective tube current (in milliamperes), resulting in decreased image noise and improved image quality [4]. During postprocessing, if the initial images are deemed to have a poor signal-to-noise ratio due to body

Figure 12 MHCT pulmonary angiography multiplanar reconstruction image. Coronal 2D reconstruction from CT pulmonary angiography study shows nonocclusive intraluminal thrombus within common basilar trunk of left lower lobe pulmonary artery (black arrow) surrounded by contrast. Occlusive thrombus is seen more distally within the lateral basilar segmental and subsegmental branches (curved white arrow). Note absence of significant stairstep artifacts. A, aorta.

Figure 12 MHCT pulmonary angiography multiplanar reconstruction image. Coronal 2D reconstruction from CT pulmonary angiography study shows nonocclusive intraluminal thrombus within common basilar trunk of left lower lobe pulmonary artery (black arrow) surrounded by contrast. Occlusive thrombus is seen more distally within the lateral basilar segmental and subsegmental branches (curved white arrow). Note absence of significant stairstep artifacts. A, aorta.

habitus or inadequate kilovolt and milliampere settings, one has the option to combine data from additional detectors to improve the image quality. For example, if the initial images are difficult to interpret due to streak artifact from hardware or foreign body, reconstructing these images with data from adjacent detectors will decrease the amount of artifact observed.

Was this article helpful?

0 0

Post a comment