Icon System Manual T02985_02_03 81
MRI System Operation
5.2.7.4 Spatial Resolution
The reachable resolution depends on the application and the type of RF Coil used. As a
rule of thumb, the in-plane resolution of a “highres”-protocol is enhanced by a factor of 1.3
~ 1.5 at about twice the scan time.
For pure anatomical 2D imaging using FLASH, the following resolutions may be expected
(slice thickness 1.0 ~ 1.25 mm):
For other methods, as well as special techniques such as multiple contrast imaging,
parametric mapping, ultra-fast imaging techniques etc., the reachable resolution within the
same scan times may be inferior.
For pure anatomical imaging, the following 3D FLASH isotropic resolutions may be
reached:
ca. (175 µm)³ within ca. 15 minutes
ca. (140 µm)³ within ca. 60 minutes
ca. (240 µm)³ within ca. 15 minutes
ca. (190 µm)³ within ca. 60 minutes
ca. (150 µm)² within ca. 4 minutes
ca. (180 µm)² within ca. 4 minutes
ca. (100 µm)² within ca.10 minutes
ca. (135 µm)² within ca.10 minutes
The slice thickness may be reduced at the expense of reduced spatial resolution in the
image plane or increased measurement time.
To keep the same image quality when reducing the slice thickness to 50%, the in-plane
resolution has to be compromised by a factor of √2 (e.g. by increasing the FOV by a
factor of √2 while keeping the same encoding matrix); or the number of averages (and
hence the total measurement time) has to be increased by a factor of 4.
For very thin slices (< 0.3 mm) 3D spatial encoding is recommended.
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