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Head
Hints in General
• Topogram: Lateral, 256 mm.
• Patient positioning:
Patient lying in supine position, arms resting against
body, secure head well in the head holder, support
lower legs.
• Gantry tilt is available for both, sequence and spiral
scanning. However, image artefacts may occur if
spirals are acquired with a tilt angle greater than 8°.
• For all head studies, it is very important for image
quality to position the patient in the center of the
scan field. Use the lateral laser beam to make sure
that the patient is positioned in the center.
• In general, cerebrum studies with contrast medium,
except CTA and nasopharynx, can be performed
by hand injection. Start the scan after the injection is
completed.
• To further optimize MPR image quality we recommend
that you reduce one or more of the following: colli-
mation, reconstruction increment, pitch factor while
using a wider slice width for image reconstruction.
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, H40s, but a more agreeable image appearance
and sometimes even better low contrast detectability,
the reason is, as with B31s and B41s, the fine-grained
noise structure. For the standard head protocols, we
propose H21s, H31s, H41s.
• High resolution head studies should be performed
with H60s, H70s (e. g. for dental and sinuses) and
H80s, H90s (e. g. inner ear).
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