Imaging: When to get MRI, CT or PET-CT?

Transcription

1 Imaging: When to get MRI, CT or PET-CT? Alina Uzelac, D.O. Assistant Clinical Professor Neuroradiology UCSF Department of Radiology and Biomedical Imaging San Francisco General Hospital Overview CT MRI PET-CT Advanced Imaging Techniques 1

2 Imaging Studies Initial Assessment Head and Neck Ca: degree of local infiltration regional lymph nodes involvement presence of distant metastases second primary tumors Local Infiltration/Tumor Extent 2

3 Orbital and Intracranial Extension Sinonasal Undifferentiated Carcinoma Ax CT Inseparable medial rectus muscle 59 F w/ trauma. Orbital and Intracranial Extension Sinonasal Undifferentiated Carcinoma Floor of anterior cranial fossa Medial rectus Cor CT 3

4 CT or MRI All Pts. initial staging MRI or CT for HEAD and NECK SCCa. particularly useful in Pts. with clinically N0 neck. CT vs MRI CT and MRI are complementary to the clinical examination. and may also be complementary to each other. 4

5 33 M with an inverted papilloma degenerated into SCCa CT = superior for cortical bone erosion Bone window Ax CT w/ Local Invasion Paraglottic fat extension 56 F w/ epiglottic mass 5

6 CT versus MRI? Ax CT w/ CT Ax T1 MRI Preepiglottic Space Extension Base of Tongue SCCa CT versus MRI? Preepiglottic Space Extension Supraglottic SCCa Sag CT w/ CT Sag T1 Motion MRI 6

7 Prevertebral Extension Pyriform Sinus SCCa Imaging Studies Initial Assessment Head and Neck Ca: degree of local infiltration regional lymph nodes involvement presence of distant metastases second primary tumors 7

8 CT versus MRI? Small Abnormal LNs Ethmoid Sinus SCCa Recurrence Preserved fatty hilum Thickened cortex 8

9 PET-CT Clinical N0 neck can be PET negative, given small node volume (<1mL). PET-CT Tongue SCCA Ax CT Small LN for PET 9

10 Thyroid Cartilage Invasion Laryngeal SCCa Ax CT w/ Ax CT w/ CT adequate for ossified cartilage Thyroid Cartilage Invasion Laryngeal SCCa Ax T1 Ax T1 w/ Gd MRI superior for marrow infiltration 10

11 Thyroid Cartilage Invasion Laryngeal SCCa Loss of nl fat bright signal Abnormal enhancement Ax T1 Ax T1 w/ Gd MRI superior for marrow infiltration Thyroid Cartilage Invasion Laryngeal SCCa Loss of fat suppression Ax T2 MRI superior marrow infiltration 11

12 33 M w/ sinonasal SCCa s/p resection returns w/ brain abscess MRI Cor T2 MRI Cor T1 w/ MRI > CT for distinguishing malignancy from mucus SCCa recurrence MRI Cor T2 MRI Cor T1 w/ MRI > CT for distinguishing malignancy from mucus 12

13 SCCa recurrence ax CT w/ cor CT w/ Returns w/ erythema and swelling Ax CT SCCa recurrence perineural spread cavernous sinus 13

14 MRI over CT Perineural spread of tumor (use thinner slice thickness - 3 mm) Intracranial extension Nasopharyngeal Ca (initial staging and follow up). Intracranial Extension Nasopharyngeal Ca bone erosion along vidian canal Ax T1 w/ ax CT 14

15 Intracranial Direct Extension SNUC Dural invasion Cor T1 Gd MRI Staging of NPC 15

16 PET-CT? Routine PET for initial staging, unless: Equivocal findings on CT or MRI. High risk of distant metastatic disease. Search for 2 nd primary. Nodal SCCa unknown primary. PET-CT To be done before Bx: Guide to area of highest yield Bx can result in high uptake. 16

17 PET-CT Superior to CT Cor PET- CT ax CT Cricoid Cartilage Invasion Subglottic SCCa Treatment Response MRI PET-CT Done 3 months post treatment completion (prevent false positives). 17

18 Nonsurgical Treatment Response - radiologic resolution = cure - reduction in size < 50% = failure % reduction = indeterminate (close surveillance) Advanced Imaging Techniques Predicting Tumor Response PET: High SUV = poor response Diffusion (DWI) MRI. Dynamic perfusion MRI (vs CT): Tumor hypoxia = radioresistance (and chemoresistance). Increased tumor perfusion => improved locoregional control. 18

19 MRI Diffusion Weighted Sequence for Tx response prediction ax DWI ax ADC Nodal metastasis Staging MRI tongue SCCa MRI Diffusion Weighted Sequence for Tx response Staging MRI Follow up ax DWI ax DWI Nodal metastasis resolution of abnl diffusion = Tx response 19

20 Recurrence Imaging MRI (extent of tumor) PET-CT (metastases) MRI Diffusion Weighted Sequence for recurrence ax DWI ax ADC Hx mod diff SCCa tongue p-hemiglossectomy, chemort, followed by LND. Recurrence, then radical neck dissection w/ pectoralis flap. 20

21 Recurrence MRI for extent of tumor 52 M w/ Hx NPCA s/p XRT in China 4 years prior Recurrence PET for metastases 35 M presents with back pain 2 years after NPC treatment Solitary NPC metastasis biopsy-proven. 21

22 Recurrence PET for flap flap 64-year-old male status post left total maxillectomy and free ALT flap for SCCa, post chemo and radiation therapy. Treatment Complications Imaging Complications occasionally incidentally imaged. MRI PET-CT 22

23 Post XRT Complications Skull base XRT changes PET negative 44yo s/p XRT for NPC. Post XRT Complications Skull base XRT changes PET negative 44yo s/p XRT for NPC. 23

24 Post XRT Complications Ax T1 w/ Gd Cor FLAIR Bitemporal XRT necrosis Post XRT Complications No abnormal hypermetabolism Ax T1 w/ Gd Cor FLAIR Ax PET Bitemporal XRT necrosis 24

25 Post XRT Complications Brain necrosis 5 years post XRT for NPC Post XRT Complications Ax Gd perfusion Bitemporal XRT necrosis 25

26 Oxaliplatin and CyberKnife Completed 07/2013 for recurrent NPC Returns 12/2013 w/ L jaw pain and trismus Oxaliplatin and CyberKnife Completed 07/2013 for recurrent NPC XRT necrosis central skull base and nasopharynx 26

27 Acute Muscle Denervation P-XRT Masticator mm. acute denervation XRT necrosis central skull base and NP PET Pitfall Acute Muscle Denervation = High Uptake Right extraocular mucles acute denervation 27

28 PET Pitfall Acute Muscle Denervation = High Uptake Right extraocular mucles acute denervation 84 M recurrent parotid malignancy perineural spread cavernous sinus. Whole Body PET-MRI 28

29 Siemens integrated PET-MRI = simultaneous imaging = superior registration Whole Body PET-MRI PET-MRI Siemens integrated PET-MRI = simultaneous imaging = superior registration 29

30 TAKE HOME POINTS Head and Neck Ca Imaging Initial Staging: CT or MRI. MRI for NPC Consider PET-CT: Distant metastases Positive neck nodes without identifiable primary Look for second primary TAKE HOME POINTS Head and Neck Ca Imaging Predicting response ADVANCED imaging: MRI Diffusion and Perfusion tumor oxygenation PET MRI-PET! 30

31 TAKE HOME POINTS Head and Neck Ca Imaging Surveillance: MRI Recurrence: MRI and PET Thank you! 31