Which factor is primarily affected when increasing matrix size in CT imaging?

Increasing the matrix size in CT imaging primarily affects spatial resolution. The matrix size refers to the number of pixels that make up the image, and a larger matrix means that the image will contain more pixels. This increase in pixel quantity allows for finer details to be represented, enhancing the overall sharpness and clarity of the images.

When the matrix size is enlarged while keeping the field of view constant, the size of each individual pixel decreases, which improves the ability to distinguish small structures within the image. This is vital for accurate diagnosis and assessment, as better spatial resolution allows radiologists to identify subtle differences in anatomy or pathology.

While other factors like CT number accuracy, contrast resolution, and image noise may also be influenced by various imaging parameters and techniques, the primary effect of increasing the matrix size is on spatial resolution. This is crucial for achieving high-quality CT images that facilitate accurate medical diagnoses.