Welcome to your CT Scan NAME: EMAIL: [Vascular components of the brain’s blood supply known as the circle of Willis include the: 1. internal carotid arteries 2. basilar artery 3. anterior communicating artery] 2 only 1 and 2 only 1 and 3 only 1, 2, and 3 None . [MSCT systems are typically capable of differentiating adjacent objects with attenuation differences as small as:] 3 HU 10 HU 25 HU 60 HU None . [Positioning the patient with the knees flexed over a foam cushion during a CT examination of the lumbar spine assists in: 1. decreasing the kyphotic curvature of the lumbar spine 2. making the patient more comfortable throughout the exam 3. decreasing the lordotic curvature of the lumbar spine] 1 only 2 only 3 only 2 and 3 only None . [An average CT number value for bone is:] þ100 HU þ500 HU þ1000 HU þ3000 HU None . [The degenerative pathologic process involving the forward slipping of an upper vertebral body over a lower vertebral body is called:] spondylolisthesis spondylolysis herniated nucleus pulposus spondylolisthesis None . [After initiation of rapid bolus administration of iodinated contrast material, the pancreatic phase of contrast enhancement occurs at approximately:] 15-25 seconds 35-45 seconds 60-70 seconds 120-180 seconds None . [The acronym CTDI is used to describe which of the following?] a specialized CT imaging technique used to mea- sure bone mineral density a quality control test that measures the accuracy of the laser lighting system the radiation dose to the patient during a CT scan a high-speed CT scanner used for cardiac imaging None . [Reformatted CT image planes that lie perpendicular to the original plane of acquisition may be described as:] oblique orthogonal obtuse orthographic None . [Which of the following technical changes would serve to decrease patient radiation dose during a CT examination?] increase in matrix size change from soft tissue to bone algorithm decrease of tube rotation from 360 to 180 degree decrease in DFOV None . [When one is assessing an MTF graph such as the figure, the limiting resolution is determined at a point where the signal frequency corresponding to a particular object has reached:] 10% 20% 50% 100% None Comment . [The density measurement performed in the figure yielded an average CT number of zero. This area consists of:] fat blood water air None Comment . [This HRCT image of the chest was most likely acquired with a section width of:] 1 mm 5 mm 7 mm 10 mm None Comment . [The imaging plane that is parallel to the foot’s plan- tar surface is called the:] coronal plane sagittal plane axial plane oblique axial plane None . [Which of the following is a manifestation of the partial volume artifact?] cupping Hounsfield bar aliasing streaking None . [Voxels with equal dimensions along the x-, y-, and z-axes are referred to as:] prospective isotropic retrospective anisotropic None . [The maximum beam collimation for an MDCT system with a detector array of 64 detectors, each 0.625 mm wide, is:] 1.25 mm 5.00 mm 10.00 mm 40.00 mm None . [The most effective method of reducing involuntary motion on a CT image is:] immobilization thorough explanation of the exam to the patient reduced scan times physical restraint None . [Which of the following angiocatheter sizes may be safely used for the automated power injection of iodinated contrast agents at flow rates higher than 3 mL/sec? 1. 18-gauge 2. 20-gauge 3. 22-gauge] 1 only 3 only 1 and 2 only 1, 2, and 3 None . [The information included during the 3D reconstruction of a CT scan is controlled by the:] algorithm window setting threshold setting None . [The graph in the figure is used to evaluate which of the following components of CT image quality? Fig. ] in-plane spatial resolution longitudinal spatial resolution temporal resolution contrast resolution None Comment . Time's up
