1 MRI of the Post-operative Neck: Revisiting the Expected and UnexpectedDave Reyes1, Heba Albasha1, Janelle Wang1, Joseph Probst,1,2, Audrey Erman1,3, Rihan Khan1,2 University of Arizona College of Medicine1 Departments of Medical Imaging2, Surgery3 Banner – University Medical Center Tucson, AZ ASNR 2016 eEdE#: eEdE-111 Control #: 2404
2 None of the authors have any relevant disclosures
3 Purpose To familiarize the reader with the expected and unexpected post-operative MRI neck findings, through multiple case illustrations of conventional and advanced imaging. Many cases will be covered, including cases from the oral cavity, mandible, larynx, hypopharynx, parotid, scalp, and sinonasal cavities. Ways to improve the MRI neck protocol will be touched on.
4 Approach/Findings Expected post-op changes Neck dissectionSurgical site Types of flaps Early/late radiation changes Post-operative complications Ways to improve the MRI Neck protocol Conclusions
5 Expected Post-Op ChangesNeck Dissection Sternocleidomastoid muscle resection (and flap placement) Submandibular gland resection Internal jugular vein resection
6 Expected Post-Op ChangesNeck Dissection Lymph node dissection: May develop scarring/fibrosis following nodal resection; note lack of fat planes Spinal accessory nerve resection: Trapezius muscle atrophies & levator scapulae muscle hypertrophies
7 Neck Dissection changes, all typesRadical neck dissection – removal of all of the following: Lymph node levels I-V (LAD I-V) Submandibular gland (resected with level I nodes) Sternocleidomastoid muscle Internal jugular vein Spinal accessory nerve (identified via levator scapula muscle hypertrophy) Modified neck dissection – removal of LAD I-V and preservation of one or more non-lymphatic structures Selective neck dissection – resection of known or potential nodal levels while preserving non-lymphatic structures
8 Post-op changes Surgical siteLow T1 and T2 signal in resection site, no mass like enhancement Check pre-op signal intensity - know what to look for post-op SCCa is T2 intermediate to dark In adenoid cystic CA, like this one, look for T2 bright signal
9 T1/T2 low signal Absence of mass like enhancementPost-op changes Surgical site T1/T2 low signal Absence of mass like enhancement Pleomorphic adenoma resected
10 Fasciocutaneous: Contains fascia, arteries, skin (no muscle or bone)Types of flaps Fasciocutaneous: Contains fascia, arteries, skin (no muscle or bone)
11 Types of flaps Myocutaneous:Contains muscle in addition to fascia, arteries, skin Types of flaps
12 Types of flaps Composite flap:Contains bone, fascia, arteries, skin, +/- muscle (i.e., mandible reconstruction) Types of flaps
13 Post laryngectomy changesNeopharynx -connects oropharynx to esophagus Tracheostomy Tracheoesophageal voice prosthesis
14 Early radiation changes2 months after completion of CT/RTX Early: Diffuse edema SubQ fat reticulation Edematous, enhancing mucosa Edematous/enhancin g salivary glands Subtle muscle swelling
15 2 months after completion of CT/RTXEarly radiation changes 2 months after completion of CT/RTX Early: Diffuse edema SubQ fat reticulation Edematous, enhancing mucosa Edematous/enhancing salivary glands Subtle muscle swelling Persistent tumor
16 27 months post CT/RTX and neck dissectionLate radiation changes 27 months post CT/RTX and neck dissection Late: Glandular atrophy; persistent enhancement common Mucosal thickening and enhancement may resolve Edema/reticulation resolves Nodes and lymphoid tissue atrophy Diffuse fibrosis
17 Post operative infection and abscesscomplications: Post operative infection and abscess Abscess with rim enhancement and restricted diffusion in floor of mouth
18 Fistula drains from floor of mouth to skin surfacePost-operative complications: Fistula formation Fistula drains from floor of mouth to skin surface
19 Upper portion shows abscess in floor of mouthFistula formation Post-operative complications Upper portion shows abscess in floor of mouth
20 Secondary Osteomyelitis & Epidural AbscessFistula Formation Secondary Osteomyelitis & Epidural Abscess Post-operative complications: Esophageal cancer Nonspecific post-op soft tissue thickening turned to fistula, osteomyelitis, and epidural abscess
21 Floor of mouth ulceration…Post-operative complications: Ulceration Floor of mouth ulceration…
22 …much worse post biopsy with hyoid osteonecrosisPost-operative complications: Ulceration …much worse post biopsy with hyoid osteonecrosis
23 Mod diff SCCa growth 6 weeks sp resectionPost-operative complications: Post-op persistent tumor Mod diff SCCa growth 6 weeks sp resection
24 Local tumor recurrencePost-operative complications: Local tumor recurrence Post-operative recurrence Operative composite flap Pre-operative tumor
25 Local tumor recurrencePost-operative complications: Local tumor recurrence Pre-operative tumor (pinna) Post-operative recurrence
26 Local tumor recurrencePost-operative complications: Local tumor recurrence Residual hypopharyngeal SCCa after chemo/RTX
27 Cerebral radiation necrosisPost-operative complications: Cerebral radiation necrosis DCE MRP Esthesioneuroblastoma Note curvilinear enhancement which conformed to radiation field
28 Post-operative Osteoradionecrosis complications:Edema and enhancement in right mandible with permeated cortex, post RTX
29 Edema and enhancement in right mandible with permeated cortex, post RTX
30 Extra-axial fluid collectionPost-operative complications: Extra-axial fluid collection Fluid collection Pre-operative tumor Operative flap
31 Pseudolesion Ameloblastoma resection Composite graftT2 bright lesion at deep margin of flap Note local susceptibility artifact from dental implant T1 without fat sat clear Watch out for fat sat susceptibility distortion!!
32 Ways to improve the MRI neck protocol: Consider BLADE/RADIAL techniques to correct for motion T1 SE post gad T1 SE BLADE post gad Motion artifact on conventional SE imaging resolved with BLADE image
33 T2 DIXON fat sat Use T2 DIXON fat saturation T2 w conventional fat satParticularly better where magnetic field is inhomogeneous due at air/soft tissue interfaces: Sinuses Chin Posterior neck Clavicles Lung apices T2 w conventional fat sat T2 DIXON fat sat
34 Use DWI: Helps detect primary and recurrent tumorsADC 1.0 DWI Recurrence along deep flap margin T2
35 Use DWI: Helps detect primary and recurrent tumorsSCCa, periauricular Mastoid extension: Ill-defined enhancement but restricted diffusion, dark T2 signal T2 T1 gad DWI CT with osseous erosion ADC
36 Try GRE based techniquesNo flow pulsation artifact Fast, limits motion Short TE limits susceptibility artifact from dental fillings
37 Nodal recurrence: Increased perfusion in right 2B nodeStart looking at DCE perfusion Nodal recurrence: Increased perfusion in right 2B node
38 Summary After the reader has reviewed the presentation, they will be able to recognize the expected MRI appearance of the post operative neck and the complications that can ensue.
39 References Moore AG, Srinivasan A. Postoperative and postradiation head and neck: role of magnetic resonance imaging. Top Magn Reson Imaging. 2015;24(1):3-13. Specialty Imaging: Head & Neck Cancer: State of the Art Diagnosis, Staging, and Surveillance. Glastonbury et al. Lippincott Williams & Wilkins. 1st edition Head and Neck Imaging. Som PM and Curtin HD. Elsevier Health Sciences. 5th edition