Published ahead of print on September 26, 2007
doi: 10.3174/ajnr.A0703
Diffusion Tensor Imaging in Joubert Syndrome
A. Porettia,
E. Boltshausera,
T. Loennekerb,
E.M. Valentec,
F. Brancatic,
K. Il'Yasovb,d and
T.A.G.M. Huismanb,e
a Departments of Pediatric Neurology, University Children's Hospital, Zurich, Switzerland
b Diagnostic Imaging and MR Center, University Children's Hospital, Zurich, Switzerland
c Department of Neurogenetics, CSS-Mendel Institute, Rome, Italy
d Department of Diagnostic Radiology, Section of Medical Physics, University of Freiburg, Germany
e Division of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins University School of Medicine, Baltimore, Md
View larger version (29K):
[in this window]
[in a new window]
|
Fig 1. Color-coded FA-maps at the level of the superior cerebellar peduncles. A, In a healthy subject, the fibers within the superior cerebellar peduncles have a slight vertical orientation, characterized by a blue color coding on color-coded FA-maps, confirming the vertical orientation of the fibers within the superior cerebellar peduncles (arrows). B, In JS, the fibers in the superior cerebellar peduncles have a more horizontal orientation, confirmed by the green color coding of the superior cerebellar peduncles on color vector DTI (arrows).
| |
View larger version (73K):
[in this window]
[in a new window]
|
Fig 2. Color-coded FA-maps at the level of the decussation of the superior cerebellar peduncles. A, In a healthy subject, on the color-coded FA-maps the decussation of the superior cerebellar peduncles is identified as a "red dot" (arrow) at the level of the inferior colliculi of the midbrain. The decussating fibers have a transverse orientation and consequently show a "red color coding." B, In JS, the absence of the "red dot" on color-coded FA-maps within the midbrain confirms the failure of the superior cerebellar peduncles to decussate. C,D, Fiber tractography displays that, in JS, the fibers within the superior cerebellar peduncles that connect the dentate nucleus with the nucleus ruber do not cross and remain ipsilateral. Axial, coronal, and sagittal anatomic T2-weighted images are projected within the display for orientation purposes.
| |
View larger version (33K):
[in this window]
[in a new window]
|
Fig 3. Color-coded FA-maps at the level of the dentate nuclei. In JS, the dentate nuclei are significantly lateralized (arrowheads).
| |
View larger version (31K):
[in this window]
[in a new window]
|
Fig 4. Color-coded FA-maps of the decussation of the pyramidal tracts. A, In a healthy subject, the transverse orientation of the decussating fibers of the pyramidal tracts can be identified as a "red dot" within the caudal medulla (arrows). B, In JS, the "red dot" is missing, indicating that the pyramidal tracts do not cross within the caudal medulla. C, Fiber tractography displays the course of the pyramidal tracts (blue encoded) in a coronal projection. No crossing fibers could be identified, and the pyramidal tracts show a parallel course within the caudal medulla. A group of the noncrossing fibers within the superior cerebellar peduncles are also displayed on the left side (green encoded). An anatomic axial section is projected within the display for orientation purposes. D, In a healthy subject, fiber tractography displays the normal course of the pyramidal tracts (blue encoded) in a coronal projection. A partially red-encoded pyramidal decussation is seen at the level of the caudal medulla (large arrows). The red-encoded decussation of the superior cerebellar peduncles is seen at the level of the mesencephalon (arrowheads). In addition, multiple red-encoded crossing fibers are seen at the level of the pons (small arrows).
| |
