How Is CT Slice Thickness Measured?

What causes contrast in an ultrasound image?

Contrast agents This phenomenon arises because the impedance for ultrasound in gas is markedly different from that for soft tissue.

Impedance is the product of density and propagation speed, and it can be appreciated that impedance in air is low whereas that in soft tissue is high..

How is slice thickness calculated in CT?

With single-slice CT, the slice thickness is determined by the detector width – with mild slice broadening just based on the pitch of the helical scan. With MDCT, slices can be composed of a single detector thickness or multiple adjacent detectors.

What is the highest slice CT scanner?

The 640-slice CT scanner uses 80% less radiation than conventional scanners. The 640-slice CT scanner can image the entire heart in less than one third of a second.

How is CT pitch calculated?

Single slice CT (SSCT) The term detector pitch is used and is defined as table distance traveled in one 360° gantry rotation divided by beam collimation 2. For example, if the table traveled 5 mm in one rotation and the beam collimation was 5 mm then pitch equals 5 mm / 5 mm = 1.0.

What is helical CT?

With helical CT, the patient is moved through a rotating x-ray beam and detector set. From the perspective of the patient, the x-ray beam from the CT traces a helical path. The helical path results in a three-dimensional data set, which can then be reconstructed into sequential images for a stack.

What is kVp in CT?

Kilovoltage peak. … Kilovoltage peak (kVp) is the peak potential applied to the x-ray tube, which accelerates electrons from the cathode to the anode in radiography or computed tomography.

What is slice thickness in CT?

Slice thickness and slice increment are central concepts that surround CT/MRI imaging. Slice thickness refers to the (often axial) resolution of the scan (2 mm in the illustration). Slice Increment refers to the movement of the table/scanner for scanning the next slice (varying from 1 mm to 4 mm in the illustration).

What does 32 slice CT scanner mean?

CT Scanner machines are differentiated by the number of slices they have, and the slice number correlates to how many images the CT scanning machine can garner per gantry rotation. For example, a 32 Slice CT Scan machine is capable of acquiring 32 images per gantry rotation.

What is a CT algorithm?

The reconstruction kernel, also referred to as “filter” or “algorithm” by some CT vendors, is one of the most important parameters that affect the image quality. … A smoother kernel generates images with lower noise but with reduced spatial resolution.

What does 64 slice CT scanner mean?

Like a traditional computed tomography (CT) scan, our 64-slice CT scan combines a series of X-ray views taken from many different angles, and then uses a computer to reconstruct the “slices” to produce actual pictures.

What is dynamic range in ultrasound?

Dynamic range The Dynamic Range is a control on the ultrasound system that allows the operator to determine the range of shades of gray to be displayed on the monitor.

What is slice thickness artifact?

1.3 Slice Thickness Artifact. This is similar to the beam width artifact but occurs due to the thickness of the beam which is 90° to the scan plane (Feldman et al. 2009 ). The slice of transducer will receive echoes from either side of the intended slice and will be included in the displayed image.

What is slice thickness in ultrasound?

Elevational Resolution • The elevational or slice-thickness dimension of the ultrasound beam is perpendicular to the image plane.

What is 128 slice CT scan?

The 128-slice CT scanner can be adapted to provide three-dimensional images for virtually any patient, young or old, of any size, includign those with cardiac or respiratory conditions that make it difficult to get high-quality images with other types of scanners.

How does multislice CT work?

A single slice CT uses X-Ray in a single detector. Whereas in a multi-slice CT, several detectors are closely placed to gather multiple layers of data in one go. In this way, the MSCT has a very high capacity to detect problems which are also the reason for their popularity in recent times.