"Hot cross bun" sign in multiple system atrophy with predominant cerebellar ataxia: a comparison between proton density-weighted imaging and T2-weighted imaging.
OBJECTIVE
To investigate whether proton density-weighted imaging can detect the "hot cross bun" sign in the pons in multiple system atrophy with predominant cerebellar ataxia significantly better than T2-weighted imaging at 3T.


METHODS
Sixteen consecutive patients with multiple system atrophy with predominant cerebellar ataxia according to the Consensus Criteria were reviewed. Axial unenhanced proton density-weighted imaging and T2-weighted imaging were obtained using a dual-echo fast spin-echo sequence at 3T. Two neuroradiologists independently evaluated visualisation of the abnormal pontine signal using a 4-point visual grade from Grade 0 (no "hot cross bun" sign) to Grade 3 (prominent "hot cross bun" sign on two or more sequential slices). Differences in grade between proton density-weighted imaging and T2-weighted imaging were statistically analysed using the Wilcoxon signed-rank test.


RESULTS
In 11 patients (69%), a higher grade was given for proton density-weighted imaging than T2-weighted imaging. In 1 patient (6%), grades were the same (Grade 3) on both images. In the remaining 4 patients (25%), signal abnormalities were not detected on either image (Grade 0). The "hot cross bun" sign was thus observed significantly better on proton density-weighted imaging than on T2-weighted imaging (P=0.001).


CONCLUSIONS
The "hot cross bun" sign considered diagnostic for multiple system atrophy with predominant cerebellar ataxia is significantly better visualised on proton density-weighted imaging than on T2-weighted imaging at 3T.
Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. nuun077@kuhp.kyoto-u.ac.jp
Seiko
S
Kasahara
Yukio
Y
Miki
Mitsunori
M
Kanagaki
Takayuki
T
Kondo
Akira
A
Yamamoto
Emiko
E
Morimoto
Tomohisa
T
Okada
Hidefumi
H
Ito
Ryosuke
R
Takahashi
Kaori
K
Togashi
D002524:Cerebellar Ataxia / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000473:pathology*; D011149:Pons / Q000473:pathology*; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D011522:Protons