Characteristic signal changes in the pontine base on T2- and multishot diffusion-weighted images in spinocerebellar ataxia type 1

Abstract

The aim of the present study was to demonstrate characteristic signal changes of the pontine base on T2-weighted images of patients with SCA 1, and to elucidate the relationship between abnormal high-intensities of the pontine base on T2-weighted images and the findings on multishot diffusion-weighted images. We assessed abnormal signals of the pontine base on T2-weighted images from 50 controls and six patients with SCA 1 diagnosed by genetic analysis. At the same time, we evaluated the degeneration of the transverse pontine fibers in the pontine base by multishot diffusion-weighted imaging. A midline high-intensity was seen in the pontine base on T2-weighted images in two of the 50 controls and five of the six patients with SCA 1. The midline high-intensity had a sensitivity of 83.3% for patients and a specificity of 96.0% for controls. Multishot diffusion-weighted imaging demonstrated the degeneration--the amorphous-pattern signal--of the transverse pontine fibers in four (66.7%) of the six patients. In the other two patients, the zebra-pattern signal was seen in the pontine base. The midline high-intensity on T2-weighted images appears to be one of characteristic MRI findings of SCA 1. Multishot diffusion-weighted imaging suggested that the midline high-intensity should reflect the degeneration of the transverse pontine fibers.

Diffusion Tensor Imaging of Spinocerebellar Ataxias Types 1 and 2

“…Nevertheless, none of the structural imaging markers taken into consideration separated SCA1 and SCA2. Midline hyperintensity in the pontine base was seen in all patients with SCA1, in accordance with a previous report by Adachi et al 24 However, because it was also found in 80% of patients with SCA2, it cannot serve as a differential diagnosis. The "cruciform sign," a typical feature of multiple system atrophy with cerebellar signs (MSA-C) reported to occur in advanced SCA2, was observed in 20% of patients with SCA1 as well.…”

“…Adachi et al 24 studied patients with SCA1, SCA3, and SCA6 but assessed DWI images qualitatively only, without measuring the ADC and FA. Della Nave et al 15 compared SCA with other neurodegenerative diseases on the basis of ADC measurements but did not compare SCA1 and SCA2.…”

Magnetic resonance imaging in spinocerebellar ataxias

“…In general, on T2-weighted images no signal abnormalities are reported in the basal ganglia and the posterior fossa. There is only one report of a midline hyperintensity of the pontine base, which is not identical with the 'cross-sign', in 5 out of 6 SCA1 patients on T2-weighted changes (23). The significance and the specificity of this finding remain unclear at present.…”

The ‘hot cross bun’ sign in the patients with spinocerebellar ataxia

“…Besides MSA‐C, HCBS has been reported in a few patients with SCA2 or SCA3 [7,8]. In one study [9], PMH has also been identified in six of the seven patients with SCA1 and two of the 50 healthy controls. A comprehensive investigation of the prevalence of HCBS and PMH in all SCA subtypes and healthy controls would help clarify their merit in the clinical practice.…”