Radiological Appearance and Imaging Techniques in the Diagnosis of Advanced Central Pontine Myelinolysis

Abstract

Conventional magnetic resonance imaging (MRI) and computed tomography (CT) are used to diagnose central pontine myelinolysis (CPM), which is seen in the setting of osmotic changes, typically with the rapid correction of hyponatremia. However, they typically follow clinical symptoms and fail to detect myelinolytic lesions within the first two weeks, limiting their efficacy in early diagnosis. CPM can mimic brainstem ischaemic changes on CT head and a glioma on MRI. This case reviews the relationship between radiological changes seen with clinical symptoms and serum sodium levels, combined with reviewing pioneering advances in radiomic analysis, including diffusion-weighted MRI, CT brain perfusion and MR spectroscopy.

Keywords: central pontine myelinolysis (cpm); computed tomography (ct); extra pontine myelinolysis (epm); hyponatremia; magnetic resonance imaging (mri).

Figure 1. Axial plain CT head at initial admission was reported as nil acute with no evidence of any abnormality

Figure 2. Axial plain CT head at the second admission 5 weeks later demonstrates central low attenuation within the lower pons (between white arrows)

Figure 3. MRI brain: sagittal T1

(a) demonstrates central pons low signal intensity (white arrow). Corresponding axial T2 (b) shows high signal (between black arrows) and trident-shaped FLAIR (c) high signal intensity (dashed white arrows) surrounding the central low signal intensity in keeping with encephalomalacia changes. FLAIR: fluid-attenuated inversion recovery

Figure 4. MRI brain: axial DWI (a) and ADC (b) demonstrates T2 shine through with low signal on DWI (between white arrows) and corresponding high signal on ADC map (between black arrows)

DWI: diffusion-weighted imaging; ADC: apparent diffusion coefficient