1. S Ghosh-Ray 1 Registrar in Radiology B Kotecha 2 Consultant in Otolaryngology S Chawda 2 Consultant in Radiology 1 - Chelsea & Westminster NHS Foundation Trust, London, United Kingdom 2 - Queen’s Hospital, Romford, Essex, United Kingdom Thursday 7 th October 2010 XIX Symposium Neuroradiologicum, Bologna, Italy 1

2. Aim of presentation  To track MRI changes of oropharyngeal tissues after bipolar radiofrequency volumetric tissue reduction (BRFVTR) surgery With a view to ○ Understanding normal changes ○ Plan follow up imaging post treatment 2

3. Sleep disordered breathing  Complex spectrum  Includes – obstructive sleep apnoea  Importance – links with acute coronary syndrome and insulin resistance 3

4. Radiofrequency Induced Thermotherapy (RFITT)  Thermal effect of high frequency current Coagulation Vaporisation Carbonisation  Used as treatment option since late 90s  Bipolar RFITT gaining momentum since 2000 Plasma induced volume reduction at lower temperatures 4

5. RF: monopolar v bipolar  Monopolar Small electrode diameter Low cost Leakage current Grounding errors  Bipolar Localised current flow Safe Better healing Less pain Patient 5

6. Ablation locations  Inferior turbinate  Tongue  Soft palate  Tonsillotomy  Tonsillectomy 6

7. Method  Cohort of 5 patients  Mixed treatment locations  MRI follow up for up to 6 weeks 7

8. Imaging – Day 1  Baseline: tongue base treatment 8

9. Imaging – Day 3  Maximum lesion size 9

10. Imaging – Day 7  Maximum lesion definition 10

11. Imaging – Day 21  Decreasing size 11

12. Imaging – Day 42 (6 weeks)  Further decrease in lesion size 12

13. Temporal Changes T1 Day 1 – lesion identified Day 3 – increased lesion size Increased definition Day 7 Decreasing lesion size Day 21 Near resolution – Day 42 13

14. Other lesions  Soft palate and uvula Pre Day 1 Day 21 Day 42 T1 STIR 14

15. Other observations  Serial measurements of soft tissue landmarks airways Nasal plane Occlusal plane Mandibular plane 15

16. Subjective measurements Uvula length and thickness Retropalatal distance: palatal plane Retroglossal distance: occlusal plane Length of tongue Retroepiglottic distance: mandibular plane 16

17. Results  Measurements Uvula length and thickness decreased All other measurements inconsistent  However, subjectively – The post BRFVTR lesion can be monitored on T1 sequences: ○ central hyperintensity: haemorrhage ○ surrounding hypointensity: oedema 17

18. Proposed follow up imaging  Post BRFVTR MRI appearances Maximum lesion definition: Day 7 Near complete resolution: Day 42 (6 weeks)  Strategy Baseline post treatment MRI at Day 7 Follow up 6 week MRI Any interim imaging can be compared to baseline to look for complications if suspected 18

19. Points to remember  No statistical analysis possible  Subjective assessment of symptoms by patients may be over-riding for outcome  MRI usefulness more in assessing complications rather than functional success 19

20. The End Thank you for your attention drdeep@doctors.net.uk 20

21. References  Back et al; Am J Respir Crit Care Med 2002; 166:865–871  Kuniyoshi et al. Day–Night Variation of Acute Myocardial Infarction in Obstructive Sleep Apnoea. J Am Coll Cardiol, 2008; 52:343-346  Schwab RJ et al. Identification of upper airway anatomic risk factors for obstructive sleep apnea with volumetric magnetic resonance imaging. Am J Respir Crit Care Med 2003;168:522-530  21

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