Mosby CT Registry Review 2024 Questions and Answers 100% Pass

Mosby CT Registry Review 2024 Questions and Answers 100% Pass What is the smallest component of a digital image - Correct Answer ️️ -pixel How many CT numbers are assigned to each pixel in the image matrix? - Correct Answer ️️ -One In a CT image, the CT number - Correct Answer ️️ -Of a material is dependent on its linear attenuation coefficient Each two-dimensional square of data that make up the CT image is called a - Correct Answer ️️ -pixel What is an element of the digital image - Correct Answer ️️ -pixel Which of the following influences the spatial resolution in cardiac CT imaging - Correct Answer ️️ -*detector size *reconstruction interval *pitch As patient motion increases spatial resolution decreases - Correct Answer ️️ -TRUE Which is an advantage of using a small focal spot - Correct Answer ️️ -increased spatial resolution Increasing the CT image matrix from 256x256 to 512x512 will likely improve? - Correct Answer ️️ -High-contrast spatial resolution The practical limiting spatial resolution of a CT scanner is 3.6 lp/cm. What size object does this correspond to? - Correct Answer ️️ -1.4 mm Use of a bone filter, as opposed to a soft tissue filter, to reconstruct CT images would likely improve? - Correct Answer ️️ -Spatial resolution The spatial resolution of a typical CT scanner is on the order of? - Correct Answer ️️ -1 mm A 512 x 512 matrix CT image over a 30-cm field of view could show a spatial resolution of no better than ? lp/cm? - Correct Answer ️️ -8.5 When comparing a 512x512 matrix to a 1024x1024 matrix, the 1024x1024 matrix? - Correct Answer ️️ -Contains four times as many pixels: 1024 x 1024 =1048576 then 512 x 512= 262144...then divide 1048576 /262144 = 4 High contrast spatial resolution and low contrast resolution are typically measured baseline and ? thereafter - Correct Answer ️️ -Biannually To improve the high contrast spatial resolution of a CT study, one would increase _____ while keeping all other factors the same. - Correct Answer ️️ -Matrix size (128x128 to 512x512) A radiologist wants to improve the high-contrast spatial resolution of anatomy which he/she is examining by CT. The change which would best lead to this improvement is - Correct Answer ️️ -Increase the matrix size To improve the high-contrast spatial resolution of a CT study, one could increase ? while keeping all other factors the same? - Correct Answer ️️ -Matrix size A voxel contains 25% air, 50% water and 25% bone. The CT number for this voxel would be expected to be _____ HU? - Correct Answer ️️ -0 How many pixels are contained in a 1,024 matrix image? - Correct Answer ️️ -D. 1,048,576 MATH 1024 X1024 It is located in a matrix and is a two dimensional representation of a voxel - Correct Answer ️️ -pixel When CT numbers are calculated for voxels (volume elements) of tissue what is assigned the calculated number and a subsequent shade of gray - Correct Answer ️️ - pixel What is defined as a picture element or the smallest component of the digital image - Correct Answer ️️ -pixel A CT scan produces a 512x512 matrix transverse image of a 30 cm diameter FOV. Each pixel is approximately _____ mm on a side. - Correct Answer ️️ -0.6 equation: 30cm/512= .058cm convert to mm and its .58 which is approximately 0.6 The ability of a system to define small objects distinctly is referred to as which of the following? - Correct Answer ️️ -spatial resolution Which of the following terms is/are commonly used to describe a CT scanner's ability to differentiate objects with similar linear attenuation coeffiecents - Correct Answer ️️ - *spatial resolution *sensitivity Which of the following factors have an affect on contrast resolution - Correct Answer ️️ -*patient size *slice thickness *pixel size *mAs/dose As mAs/dose increases contrast resolution decreases - Correct Answer ️️ -FALSE As mAs/dose increases contrast resolution INCREASES - Correct Answer ️️ -TRUE The ability of a CT scanner to accurately image objects with similar densities is termed - Correct Answer ️️ -*contrast resolution *sensitivity Which of the following has a direct relationship on increasing contrast resolution - Correct Answer ️️ -*mAs/dose increase *Slice thickness For a particular CT scanner's beam quality, the linear attenuation coefficient for water is 0.20 cm-1 and for a certain tumor is 0.21 cm-1. What is the CT number of the tumor? - Correct Answer ️️ -50. Equation (.21-.20/.21) × 1000= 50 A CT scanner with poor contrast resolution or low sensitivity has difficulty separating - Correct Answer ️️ -tissues whose linear attenuation coefficients are nearly equal What is the basic physical quantity being measured by a CT system - Correct Answer ️️ -Linear attenuation coefficient