Knowing what, when and how to interpret: Guide to imaging salivary gland pathology

1. eEdE#: eEdE-127 Knowing what, when and how to interpret: Guide to imagingsalivary gland pathology Umar Chaudhry+, Saba Hamid+, Umber Shafique+, Joan Maley+, Bruno Polliceni+, Henry Hoffmman* + Section of Neuroradiology, Department of Diagnostic Radiology, Univeristy of Iowa Hospitals and Clinics. * Department of Otolaryngology, University of Iowa Hospitals and Clinics.

2. Outline • INTRODUCTION • MODALITIES AVAILABLE • INDIVIDUAL MODALITIES • INDICATIONS • PROTOCOL • ADVANTAGES • DISADVATAGES • PICTORIAL EXAMPLES • PEARLS “ The years teach much which the days never knew ” Ralph Waldo Emerson

3. INTRODUCTION Salivary gland pathology is one the most variable amongst the organ system Wide variety of imaging modalities used It becomes confusing to determine the most optimum modality when encountered with a clinical scenario With era of cost effectiveness, ever increasing patient awareness, and extensive clinician interactions, the expectations from a radiologist have increased This presentation is intended to be a quick reference guide and refresher for various tools in our arsenal when dealing with such scenarios

4. modalities Computed Tomography Magnetic resonance imaging Ultrasound Conventional Sialography Nuclear imaging

5. COMPUTED TOMOGRAPHY (CT)

6. Indications: Optimal: • Inflammatory pathologies, infection • Obstructive pathologies: stones Occasional: • CT sialography, ductal pathology • Masses • Post radiation

7. Protocol • Multidetector CT (MDCT) • kVP 80-120 kVP • Dose reduction techniques: • Thyroid bismuth shields • Automated dose reduction • Lower kV • Studiesshowed no significant diagnostic difference between 80 and 120 kV protocols • Inflammatory conditions, abscess usually IV contrast • Stones - Non contrast

8. Advantages -Quick -Readily available -Gross anatomical detail of surrounding structuresextent of inflammation -High sensitivity for Stones/calcifications - 3D reconstructions: CT Sialography

9. Disadvantages • Ionizing radiation- pregnant and children • Not ideal for tumors as higher detail from MRI • Perineural spread in malignancies is difficult • Poor ductal anatomical detail with standard CT

10. Inflammation of left parotid gland

11. A case of a left parotid gland tumor – pleomorphic adenoma with spilling, structural details and margins not as clear as with MRI

12. Right submandibular gland duct stone (rectangle) with dilated duct (circle)

13. Pearls - CT • Acute conditions in adult patients • Inflammation • Stones questioned • With radiation awareness, consider dose modulation

14. Magnetic resonance imaging (MRI)

15. Indications Salivary gland masses Systemic conditions, usually non acute Ductal anatomy - Sialography

16. protocol • For masses or major salivary glands, usually gadolinium based contrast • Varies from one institution to the other • Our institution protocol • 3 plane localizer • Coronal and axial T2 • Axial T1 • Diffusion • 3 plane post -contrast T1 images

17. Example of scan volumes for parotid gland

18. MRI sialography • Relies on heavily T2 weighted sequences and water property of saliva • Side of abnormality and duct included in the scan volume for MR Sialography • Protocol also varies from institution to institution • 2D pulse sequences used traditionally - Projection and Maximum Intensity projections for Sialography • 2D pulse sequence techniques to increase quality of images include • Projection technique by using a microscopic coil improving the quality of the images obtained with larger coils • Recently 3D pulse sequences utilized for more post processing options

19. Advantages • No radiation • Non invasive • Excellent gland detail • Tumor characterization, using signal intensity, margins, pattern of spread, diffusion coefficients • Facial nerve characterization in parotid lesions

20. Disadvantages • Time consuming - not ideal for acute settings • Expensive • Limited field of view • More susceptible to artifacts • Ductal detail needs careful optimization, otherwise may be confounded by vessels etc.

21. Pearls • Non acute • Ideal for major salivary gland masses and systemic conditions such as Sjogren characterization • Spread of malignancies- perineural tumor spread • New techniques such as dynamic contrast high potential • After optimization ductal details acquired non invasively

22. Pleomorphic adenoma on mri Post contrast homogenous T1- low T2- high

23. Malignant parotid tumor with perineural tumor spread (circle)

24. Ultrasound

25. Indications: • Acute inflammations • Pediatric and pregnant population • Image guided procedures • Initial screening of major salivary gland mass

26. Protocol • High frequency linear probes • 7.5-12 MHz • Color doppler • Real time imaging Figure: Example of color doppler on a parotid mass

27. Advantages • No ionizing radiations • Quick • Real time imaging- image guided procedures • Less expensive and more readily available than MRI

28. Disadvantages • Operator dependence • Ducts especially Parotid duct not well seen unless largely dilated • Limited field of view- Deeper pathologies such as parapharyngeal space lesions and deep lobes of parotid glands not well see • Less specific characterization of masses as compared to MRI

29. Parotid pleomorphic adenoma Normal parotid parenchyma is more echogenic and homogenous

30. Pearls • Children and pregnant patients • Initial screening for acute conditions such as infections • Image guided procedures • One of the most cost effective modalities in cross sectional imaging

31. Conventional Sialography

32. Indications: • Obstructive and ductal salivary gland pathology • Preoperative exam before sialendoscopy

33. Protocol • Fluoroscopy- real time imaging • Usually Kv range close to 70 kV • Iodine based contrast directly instilled into major salivary gland ducts • Images in two planes • Ductal and glandular phase • Stimulation for glandular phase - Lime/candy

34. Sialography- The Procedure Sialography -technique • Basic principle: Instilling radio-opaque contrast directly into the duct opening Salivary Gland Stenson’s duct Canula Syringe containing contrast Sialography can be performed with or without digital subtraction - digital subtraction favored, as it removes the confounding bone opacities

35. Advantages • Resurgence due to preoperative insight before minimally invasive ENT procedures • Ductal resolution and detail superior to many other modalities • Lower dose than CT sialography

36. Disadvantages • Invasive • Ionizing radiation • Expertize required

37. Common pathologies-a sialographic perspective Sialography in sialolithiasis Filling defects seen in Stenson’s duct, with dilated ducts upstream from the obstruction

38. Pearls • Not to be overlooked and seeing a resurgence due to new minimally invasive techniques in ENT • Ductal pathology well seen • Usually requires close collaboration with ENT

39. Nuclear medicine

40. Indications: • Long term dysfunction/sialadenitis • Metastatic workup

41. Protocol • Salivary scintigraphy • Tc-99m Planar and SPECT imaging • Mainly for long term dysfunction after radioiodine • PET • Fluoro-deoxy glucose for metastatic workup and distant lesions

42. Advantages • Functional information • Distant metastatic lesions

43. Disadvantages • Non-specific for salivary gland tumors • Non acute pathologies only • Limited use • Cost and availabillity

44. PET-fdg scan in metastatic salivary gland tumor: Neck node and right lung nodule

45. Pearls • Overall limited role • Chronic sialadenitis after radioactive iodine- Tc-99m scintigraphy • FDG-PET is non specific, can be used for distant metastasis after tissue diagnosis

46. references • Carotti M, Ciapetti A, Jousse-Joulin S, SalaffiF.Ultrasonography of the salivary glands: the role of grey-scale and colour/power Doppler.ClinExpRheumatol. 2014 Jan-Feb;32(1 Suppl 80):S61-70. Epub 2014 Feb 17. • AghaghazviniL, Salahshour F, Yazdani N, Sharifian H, Kooraki S, Pakravan M, Shakiba M. Dynamic contrast-enhanced MRI for differentiation of major salivary glands neoplasms, a 3-T MRI study.DentomaxillofacRadiol. 2015;44(2):20140166. • Burke CJ, Thomas RH, Howlett D. Imaging the major salivary glands. Br J Oral Maxillofac Surg. 2011 Jun;49(4):261-9. Epub 2010 Apr 9. • Harrison JD. Causes, natural history, and incidence of salivary stones and obstructions. OtolaryngolClin North Am. 2009 Dec;42(6):927-47. • Brown JE, Drage NA, Escudier MP, Wilson RF, McGurk M. Minimally invasive radiologically guided intervention for the treatment of salivary calculi. CardiovascInterventRadiol. 2002 Sep-Oct;25(5):352-5. Epub 2002 Sep 18.

47. references • Abdullah A, Rivas FF, Srinivasan A. Imaging of the salivary glands.SeminRoentgenol. 2013 Jan;48(1):65-74. • Gonzalez-Beicos A, Nunez D. Imaging of acute head and neck infections.RadiolClin North Am. 2012 Jan;50(1):73-83. • Obinata K, Sato T, Ohmori K, Shindo M, Nakamura M. A comparison of diagnostic tools for Sjögren syndrome, with emphasis on sialography, histopathology, and ultrasonography. Oral Surg Oral Med Oral Pathol Oral RadiolEndod. 2010 Jan;109(1):129-34. • Nahlieli O, Nakar LH, Nazarian Y, Turner MD. Sialoendoscopy: A new approach to salivary gland obstructive pathology. J Am Dent Assoc. 2006 Oct;137(10):1394-400. • Mosier KM. Diagnostic radiographic imaging for salivary endoscopy. OtolaryngolClin North Am. 2009 Dec;42(6):949-72.

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