return to: Sialograms and Sialography
Sialography is a digitally recorded radiographic modality used for both anatomical and functional evaluation of the salivary glands. Contrast medium is infused into the Stensen’s or Wharton’s duct for evaluation of the parotid or submandibular glands, respectively, to outline and assess the anatomy.
Sialography has proven to be a useful technique throughout the years and, despite the availability of newer imaging procedures, continues to have a dominant role in our practice addressing salivary gland disorders (Kalk 2001). With the introduction of sialoendoscopic procedures for salivary gland obstructions, sialography has re-emerged as an important minimally invasive technique (Hasson 2010).
The safety of sialography is high with our exclusive use of water-soluble iodinated contrast medium rather than oil-based contrast. Although multiple articles list allergy to the contrast medium (usually the iodine) as a contraindication, our practice has been to pre-treat these highly selected patients with steroids as per our radiology protocol prior to adminstration of IV iodinated contrast for CT imaging. The risk of administering ~ 2 to 5 cc's (Isovue 370) into the salivary duct felt to be much less than the ~100 cc's (or more) often given intravascularly for contrasted CT imaging (Hasson 2010). (see: Iodine Allergy Protocols for Contrast) Reaction to contrast medium has been reported to occur in 2-10% of investigations but has not been identified in our practice as yet.4 Such allergic reactions demonstrate more commonly in patients who are atopic or have a history of allergic reaction to drugs or contrast medium (Salerno 2002), (Preece 1984) and (Cockrell 1993). An alternative approach for patients unable to tolerate iodinated contrast is to use gadolinium as a contrast agent (Williams 2003). We have used gadolinium successful for conventional sialography in multiple patients with iodine allergry - identifying the studies to be of adequate quality but lacking some of the greater definition provided with conventional iodinated contrast.
Lipiodol is an oil-based iodinated contrast medium. Though lipiodol in the past was reported to render sharper images than its water-based alternative, case reports demonstrate a comparatively poor elimination from the salivary glands (Ozdemir 2004), (El-Hadary 1986). The retention is mainly observed as small radio-opaque spots in the gland periphery, (Schortinghuis 2009) and may interfere with subsequent computed tomography imaging. Because of its high viscosity, oil-based contrast medium also requires more pressure during infusion. Due to potential problems with retention of oil-based contrast media (especially in cases of with extrusion outside of the duct or gland) we (H Hoffman, U of Iowa) have limited our practice of sialography since 2008 to use of water-soluble iodinated contrast medium.
Water-soluble iodinated contrast medium is lower in viscosity and demonstrates no retention within the ducts or gland parenchyma (Weissman 1995). The use of higher density contrast media (Isovue 370) has negated the previously considered liability of water soluble contrast that in the past was associated wtih decreased radiographic density and poor visualization of peripheral ducts in comparison with oil-based contrast medium.
Because the procedures for sialographic imaging (for more information, go to: Sialogram Technique) involve the dilatation of salivary ducts and the infusion of contrast medium, the most common associated complaints are of pain or swelling of the salivary gland. Such reports vary from patient to patient, ranging from no pain or discomfort, minimal pain during the infusion of contrast medium, or transiently lasting pain or swelling after the evaluation.2 For most, the pain or swelling lasts for 24-48 hours before gradually subsiding.10
Extravasation of radiocontrast outside of the ductal lumen has been reported as significant complication when using oil-based contrast agents. Through our review of 255 consecutive sialograms employing water based contrast, a 4.7% percent extrusion rate was identified - and in each case associated with the ductal pathology of stenosis. In no cases were there complications from the extrusion with resorption occurring over several days (Truong 2018).
References
Weissman JL. Imaging the salivary glands. Semin Ultrasound CT. 1995;16(6);546-568.
Kalk WWI, Vissink A, Spijkervet FKI, et al. Morbidity from parotid sialography. J Oral Surg. 2001;92:572.
Hasson O. Modern sialography for screening of salivary gland obstruction. J Oral Maxillofac Surg. 2010;68:276-280.
Salerno S, Cannizzaro F, Lo Casto A. Late allergic reaction following sialography: letter. Dentomaxillofac Rad. 2002;31:154.
Preece JW. Choice of contrast medium in sialography. Oral Surg. 1984;57:323-337
Cockrell DJ, Rout PGJ. An adverse reaction following sialography. Dentomaxillofac Rad. 1993;22:41-42.
El-Hadary A, Reprecht A. Long-term retention of contrast medium in sialography: a case report. Dentomaxillofac Rad. 1986;15:41-44.
Ozdemir D, Polat NT, Polat S. Lipiodol UF retention in dental sialography. Br J Rad. 2004;77:1040-1041.
Schortinghuis J, Pijpe J, Spijkervet FKL, Vissink A. Retention of lpiodol after parotid gland sialography. Oral Maxillofac Surg. 2009;28:346-349.
Salerno S, Lo Casto A, Romano I, Cannizzaro F, Speciale R, Midiri M. Morbidity of salivary gland digital sialography using a non-ionic dimeric contrast medium. Minerva Stomatol. 2008;57(6):285-294.
Truong K, Hoffman HT, Policeni B, Maley J. Dye Extravasation During Sialography.Ann Otol Rhinol Laryngol. 2018 Mar;127(3):192-199. doi: 10.1177/0003489417752711. Epub 2018 Jan 7
Williams MD, Moody AB, Newlands CA, Howlett DC. Gadolinium an alternative contrast agent for sialography in patients with iodine sensitivity. Int J Oral Maxillofac Surg. 2003 Dec;32(6):651-2. doi: 10.1054/ijom.2002.0439. PMID: 14636619.
Sabotin R, Thorpe R, Maley J, Policeni B, and Hoffman H: Gadolinium as a Contrast Agent for InfusionSialograms in Patients with Iodine Allergy - Triological Society Poster Presentation (Poster C59) Friday May 5 2023 Boston Massachusetts <ResearchPosters.com – Print, ePoster, and Virtual Poster Sessions accessed 8-08-2023>