Mengenal System Kernels pada CT Scan Siemens

There are 5 different types of kernels: H stands for Head, B stands for Body, U stands for High Resolution, C stands for ChildHead and S stands for Special Application, e.g. syngo Osteo CT. The image sharpness is defined by the numbers – the higher the number, the sharper the image; the lower the number, the smoother the image.
The endings “s” or “f” depend on the rotation time.

Head Kernels:

Kernel        description
H10f, H10s very smooth
H20f, H20s smooth
H21f, H21s smooth +
H22f, H22s smooth FR
H30f, H30s medium smooth
H31f, H31s medium smooth +
H32f, H32s medium smooth FR +
H37f, H37s medium smooth
H38f, H38s medium smooth
H40f, H40s medium
H41f, H41s medium +
H42f, H42s medium FR +/medium FR
H45f, H45s medium
H47f, H47s medium smooth
H48f, H48s medium smooth
H50f, H50s sharp
H60f, H60s medium

Body Kernels:

Kernel             description
B10f, B10s      very smooth
B20f, B20s      smooth
B30f, B30s      medium smooth
B31f, B31s     medium smooth +
B35f, B35s     HeartView medium
B36f               HeartView medium
B40f, B40s     medium
B41f, B41s     medium+
B45f, B45s     medium
B46f              HeartView sharp
B50f, B50s    medium sharp
B60f, B60s   sharp
B70f, B70s    very sharp
B75f, B75s   very sharp
B80f, B80s    ultra sharp

Child Head Kernels:

Kernel          description
C20f, C20s    smooth
C30f, C30s   medium smooth C60s sharp

Ultra High Resolution:

Kernel          description
U30u            medium smooth
U40u            medium
U70u           sharp
U80u           very sharp
U90u          ultra sharp
U95u          special applications

Special Application:

Kernel            description
S80f, S80s Shepp-Logan with notch filter
S90f, S90s Shepp-Logan without notch filter

PET-Kernel:

Kernel            PET
B19s/f            smooth
B29s/f           medium smooth
B39s/f           medium
H19s/f           smooth
H29s/f          medium smooth
H39s/f          medium

Head Kernels
For soft tissue head studies, the standard kernel is H40s; softer images are obtained with H30s or H20s, H10s, sharper images with H50s. The kernels H21s,  H31s, H41s yield the same visual sharpness as H20s, H30s or H40s, respectively. The image appearance,
however, is more acceptable due to a "fine-grained" noise structure; quite often, the low contrast detectability is improved by using H31s, H41s instead of H30s, H40s.
In emergency examinations, kernels H22s, H32s, and H42s can be used because they allow fast reconstruction (FR) and easy patient positioning (50 cm FoV). To ensure best performance, special online bone correction (PFO) is not used.
High Resolution head studies should be performed with H50f, H60f (for example, for dental and sinuses). It is essential to position the area of interest in the center
of the scan field. For a better gray-white brain tissue differentiation use the H37f/s, H38f/s or H47f/s kernel.
Child Head Kernels
For head scans of small children, the kernels C20s, C30s (for example for soft tissue studies) and C60s (for example, provided for sinuses) should be chosen instead of the "adult" head kernels H20s, H30s and H60s.

Body Kernels
As standard kernels for body tissue studies B30s or B40s are recommended; softer images are obtained with B20s or B10s (extremely soft). The kernels B31s or B41s have about the same visual sharpness as B30s respectively, B40s, the image appearance, however, is more acceptable due to a "fine-grained" noise structure; quite often, the low contrast detectability is improved by using B31s, B41s instead of B30s, B40s.
For higher sharpness, as is required for example, in patient protocols for cervical spine, shoulder, extremities, thorax, the kernels B50s, B60s, B70s, B80s are available.

Special Application Kernels and Ultra High Resolution Kernels For special patient protocols, S80s and U90u are chosen, e. g. for osteo (S80s) and for High Resolution bone
studies (U90u).
We recommend using the High Resolution specification kernel U90u only with "small" objects, like the wrist, otherwise artifacts will occur in the images.
Note:
• In the case of a 3D study only, use kernel B10s and at least a 50% overlap for image reconstruction.
• Do not use different kernels for body parts other than what they are designed for.

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