1 Radiology Department, Wrightington, Wigan and Leigh NHS foundation Trust, Royal Albert Edward Infirmary, Wigan Lane, Wigan, WN1 2NN, UK. jun-li.tham@wwl.nhs.uk.
2 Radiology Department, Wrightington, Wigan and Leigh NHS foundation Trust, Royal Albert Edward Infirmary, Wigan Lane, Wigan, WN1 2NN, UK.