Vertical pons hyperintensity and hot cross bun sign in cerebellar-type multiple system atrophy and spinocerebellar ataxia type 3

Atsuhiko Sugiyama,Satoshi Kuwabara,Kyosuke Koide,Yoshitaka Yamanaka,Hajime Yokota,Shoichi Ito,Shigeki Hirano,Tatsuya Yamamoto,Hiroki Mukai

doi:10.1186/s12883-020-01738-9

Atsuhiko Sugiyama, Satoshi Kuwabara + Show 7 more

Open Access

https://doi.org/10.1186/s12883-020-01738-9

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Abstract

BackgroundThe “hot cross bun” (HCB) sign, a cruciform hyperintensity in the pons on magnetic resonance imaging (MRI), has gradually been identified as a typical finding in multiple system atrophy, cerebellar-type (MSA-C). Few reports have evaluated the sensitivity of an HCB, including a cruciform hyperintensity and vertical line in the pons, which precedes a cruciform hyperintensity, in the early stages of MSA-C. Moreover, the difference in frequency and timing of appearance of an HCB between MSA-C and spinocerebellar ataxia type 3 (SCA3) has not been fully investigated.MethodsThis study investigated the time at which an HCB and orthostatic hypotension (OH) appeared in 41 patients with MSA-C, based on brain MRI and head-up tilt test. The MRI findings were compared with those of 26 patients with SCA3. The pontine signal findings on T2-weighted MRI were graded as 0 (no change), 1 (a vertical T2 high-intensity line), or 2 (a cruciform T2 high-intensity line), with grades 1 or 2 considered as an HCB. OH 30/15 was defined as a decrease in systolic blood pressure of > 30 mmHg or diastolic blood pressure of > 15 mmHg.ResultsAmong the 24 patients with MSA-C within 2 years from the onset of motor symptoms, an HCB was detected in 91.7%, whereas OH 30/15 was present in 60.0%. Among the 36 patients with MSA-C within 3 years from the onset of motor symptoms, a grade 2 HCB was detected in 66.7% of those with MSA-C but in none of those with SCA-3.ConclusionsHCB is a highly sensitive finding for MSA-C, even in the early stages of the disease. A grade 2 HCB in the early stage is an extremely specific finding for differentiating MSA-C from SCA-3.

Highlights

The “hot cross bun” (HCB) sign, a cruciform hyperintensity in the pons on magnetic resonance imaging (MRI), has gradually been identified as a typical finding in multiple system atrophy, cerebellar-type (MSA-C)
On comparing patients with Multiple system atrophy (MSA) and spinocerebellar ataxia type 3 (SCA3) and control subjects, it was found that patients with MSA were older than the patients with SCA3 when MRI was performed (p = 0.003) and were older than patients with SCA3 at disease onset (p < 0.001)
On comparing patients with MSA-C and SCA3 and control subjects, it was found that patients with MSA-C were older than the patients with SCA3 at disease onset (p < 0.001)

Summary

Introduction

The “hot cross bun” (HCB) sign, a cruciform hyperintensity in the pons on magnetic resonance imaging (MRI), has gradually been identified as a typical finding in multiple system atrophy, cerebellar-type (MSA-C). Few reports have evaluated the sensitivity of an HCB, including a cruciform hyperintensity and vertical line in the pons, which precedes a cruciform hyperintensity, in the early stages of MSA-C. It is important to overcome the poor sensitivity of the second consensus criteria in MSA diagnosis during the early stages of the disease. The “hot cross bun” (HCB) sign, that is, a cruciform hyperintensity in the pons on T2-weighted imaging (T2WI), was named for the Easter pastry it resembles and was reported to be a typical feature of MSA [4, 5]. Focusing on a vertical line preceding a cruciform hyperintensity in the pons may increase sensitivity, few reports have examined the sensitivity of a vertical hyperintensity in the pons in the early disease stage

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