Footnotes

• Contributors WW-SN was the lead author involved in drafting the initial manuscript and preparing the images. KC provided radiological expertise including interpretation and description of the images. All authors contributed to the writing, review and final approval of the manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.