Diffusion tensor imaging in Joubert syndrome.
OBJECTIVE
Neuropathologic findings and preliminary imaging studies demonstrated the absence of pyramidal tract and superior cerebellar peduncular decussation in individual patients with Joubert syndrome (JS). We hypothesized that functional-structural neuroimaging findings do not differ between the genetic forms of JS.


METHODS
MR imaging was performed with a 3T MR imaging-unit. Multiplanar T2- and T1-weighted imaging was followed by diffusion tensor imaging (DTI). Isotropic diffusion-weighted images, apparent diffusion coefficient maps, and color-coded fractional anisotropy maps, including tractography, were subsequently calculated.


RESULTS
In all 6 patients studied, DTI showed that the fibers of the superior cerebellar peduncles did not decussate in the mesencephalon and the corticospinal tract failed to cross in the caudal medulla. The patients represented various genetic forms of JS.


CONCLUSIONS
In JS, the fibers of the pyramidal tract and the superior cerebellar peduncles do not cross, irrespective of the underlying mutation.
Poretti
A
A
Department of Pediatric Neurology, University Children's Hospital, Zurich, Switzerland.
Boltshauser
E
E
Loenneker
T
T
Valente
E M
EM
Brancati
F
F
Il'yasov
K
K
Huisman
T A G M
TA
D000015:Abnormalities, Multiple / Q000235:genetics / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D001921:Brain / Q000002:abnormalities*; D002531:Cerebellum / Q000473:pathology; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D011712:Pyramidal Tracts / Q000473:pathology; D013577:Syndrome