Clinical insights on sialography in the era of modern imaging: A case report of 5 cases

Abstract

Sialography offers a unique advantage for mapping the salivary duct network and identifying structural inconsistencies. It clearly demonstrates the presence and extent of benign obstructions, dilatations, and ductal variations that may appear only as nonspecific sialadenitis on ultrasonography. Furthermore, the flow and composition of the contrast media provide a therapeutic benefit. This case series, supported by comprehensively annotated procedural images, highlights the merits of sialography as a corroborative diagnostic tool—especially when point-of-care ultrasound (POCUS) fails to accurately detect microliths or subtle ductal discrepancies. This article provides an oral healthcare professional’s perspective on diagnosing benign obstructive salivary gland disorders.

Introduction

Often limited access to advanced diagnostic/interventional imaging or nondescript presentation on ultrasound, results in missed diagnoses of salivary ductal disorders. Recurring bouts of glandular inflammation stemming from undiagnosed intra-ductal inconsistencies or obstructions are associated with morbidity of gland excision. Sialography presents the unique ability to reveal such miniscule ductal anomalies, providing the accurate description of pathology beyond the blanketed term of “sialadenitis.” Judicious application of this fairly basic radiological approach could aid in triaging patients for either minimally invasive gland-sparing procedures or gland excision or simply symptom-based care within the domain of benign obstructive disorders of salivary glands [1].

Procedural protocol

Under standard aseptic conditions, the symptomatic salivary gland was catheterized with Rabinov type blunt-tipped side-injecting sialography cannula of appropriate size determined by the calibre of ductal orifice, which was first dilated with gutta-percha points. Urografin 76% (Diatrizoate Meglumine and Diatrizoate Sodium) was then infused into the gland until firm pressure was felt and visible enlargement occurred over the glandular region. The cannula remained in place to plug the orifice during the scan, preventing intraductal voids caused by contrast leakage. Following the acquisition of radiographs and volumes (acquired with Carestream CS 8100 SC 2d and Vatech Green X CBCT), the cannula was withdrawn to allow for spontaneous contrast extrusion, aided by a gentle forward massage. Oral radiologists interpreted the images and volumes after they were processed using a combination of proprietary and open-source software.

Case 1

Case summary: A patient presented with a 4-year history of bilateral recurrent parotid swelling and clinical sign of xerostomia.

Imaging findings: Sialography of the parotid and submandibular glands revealed punctate sialectasis (Fig. 2A–D). Complementary USG of the major salivary glands showed multiple hypoechoic areas diffusely scattered throughout the superficial lobes of the parotid and submandibular glands.

Fig. 2.

(A and B) Cropped OPG and AP “puffed cheek” views as part of conventional sialography of parotid gland, illustrating the ductal and parenchymal opacification with early sialodochitis of proximal end of the main duct (6) with significant architectural loss of secondary and terminal ducts. Sialectasis of “punctate” type seen scattered evenly in a pan-glandular fashion (4). The findings are suggestive of autoimmune sialosis. (C and D) Conventional sialography presented as a lateral projection and cropped view of OPG with lobulation (8) and capsular enhancement (9) within right submandibular gland and typical “punctate” type Sialectasis, contra-laterally (4). (Refer Table 1 for number legends)

Management: The patient was diagnosed with primary Sjögren’s syndrome (scoring 7 on the 2016 ACR/EULAR classification criteria) and referred to a rheumatologist. Symptomatic care included alternating retrograde irrigations of the major salivary glands with parenteral antibiotics (metronidazole, amoxicillin) and steroids (dexamethasone 4mg/ml).

Follow up: Patient remains under observation.

Case 2

Case summary: A 50-year-old patient presented with a long-standing swelling in the right submandibular region and xerostomia, potentially exacerbated by antihistamine use for allergic rhinitis. The patient reported that the swelling increased slightly during mealtimes.

Imaging findings: Previous repeated ultrasounds of the submandibular glands were noncontributory. In the absence of acute inflammation, sialography of the right submandibular gland was performed, revealing a significant, previously undiagnosed extra-glandular stricture in the primary duct (Fig. 3A).

Fig. 3.

(A) Conventional Sialography of the submandibular gland recorded as a partial OPG image illustrates a stricture of significant length traversing along the mid region of the main duct (11). Parenchymal flushing with excellent representation of glandular lobules (8,13) and (B) Sialogram of submandibular gland recorded as a cropped view of OPG reveals advanced pan-ductal sialodochitis (6) associated with negative filling defects (10). Abrupt right-angled bends (14) noted along the distal portion of the primary duct. (Refer Table 1 for number legends)

Management: The patient was advised to maintain adequate hydration and perform regular glandular massage to encourage saliva drainage past the stricture. Following an unsuccessful initial catheterization attempt, balloon ductoplasty via sialoendoscopy was rescheduled.

Follow up: The patient continues symptomatic care while awaiting the follow-up sialoendoscopy.

Case 3

Case summary: A 48-year-old female presented with an 8-month history of recurrent swelling in the right submandibular region.

Imaging findings: While ultrasonography suggested sialadenitis without evidence of obstruction, sialography revealed a highly tortuous Wharton’s duct with abrupt bends. An extra-glandular filling defect confirmed the presence of a sialolith (Fig. 3B), accompanied by sialodochitis of the primary and peripheral ducts.

Management and follow up: The patient underwent sialolithotomy with sialodochoplasty and retrograde irrigations. She remained asymptomatic following the procedure.

Case 4

Case summary: A 58-year-old female presented with a year-long history of an unpleasant salty discharge from the right buccal mucosa, intermittently accompanied by pain in the parotid region. Clinical examination revealed mucus-laden saliva upon proximal-to-distal massage of Stensen’s duct.

Imaging findings: Previous MRI showed bilateral parotid enlargement with primary duct dilatation; USG findings suggested bilateral parotitis. To map the ductal anomalies and screen for minor obstructions, CBCT sialography was performed. It revealed pronounced, uneven dilatation of the primary ducts (maximum hilar caliber: 4.3 mm and 5.6 mm, for left and right stenson's ducts, respectively) with intermittent filling defects and strictures (Fig. 4A-D), consistent with Marchal LSD classification L0 S3 D2. The sialographic presentation suggested advanced sialodochitis with multifocal intra-glandular benign obstructions. These extensive strictures precluded interventional access via sialoendoscopy.

Fig. 4.

(A and B) (Maximum intensity projections) Lateral CBCT Sialography images of bilateral parotid show prominent ductal architectural inconsistency demonstrated by intermittent sialodochitis (6), ectasia (18), strictures (11) sialectasis (5) and filling defect (10). (C and D) Axial CBCT Sialography images of bilateral parotid show multiple filling defects (10) along the main duct, not depicted previously on lateral images (above) and (E) Lateral CBCT Sialography of parotid in a patient suspected with Kussmaul disease (sialodochitis fibrinosa) with raised serum IgE levels, depicts sialodochitis (6) involving secondary ducts with punctate (4) to globular (5) acinar pooling (sialectasis) scattered within the superior portion of the glandular parenchyma. (Refer Table 1 for number legends).

Management and follow up: Treatment consisted of retrograde irrigations with parenteral antibiotics and dexamethasone, combined with self-care (hydration and regular glandular massage). This regimen resulted in a favorable outcome with improved glandular function.

Case 5

Case summary: 31-year-old male presented with a long-standing history of left parotid swelling, frequently accompanied by inflammation and salivary obstruction. Physical examination revealed thick mucinous plugs expressed upon gentle rolling pressure over the gland.

Imaging findings: Repeated ultrasounds were unremarkable. However, CBCT sialography revealed a “sausage-link” appearance of the peripheral ductules with punctate to cavitary sialectasis (Fig. 4E), consistent with Marchal LSD classification L0 S0 D2.

Supportive investigation: Serum analysis showed elevated IgE levels and an absence of autoimmune serologic markers. A diagnosis of Kussmaul disease (sialodochitis fibrinosa) was made by exclusion, despite the lack of a known history of atopy.

Management and follow up: Treatment included supportive care and intra-ductal irrigations, which resulted in subjective improvement at each follow-up visit (Table 1).

Table 1.

Descriptive terms for number legends.

1-Primary duct	2-Secondary ducts
3-Terminal ductules	4-Punctate sialectasis
5-Globular sialectasis	6-Sialodochitis
7-Hilum	8-Enhanced lobular architecture
9-Capsular enhancement	10-Negative filling defect representing sialolith/mucous plug
11-Stricture	12-Accessory glandular tissue
13-Parenchymal flushing/acinar opacification	14-Abrupt bend
15-Flexible tubing	16-Sialographic cannula
17-Proximal ductal dilatation	18-Ectasia

Discussion

The authors of this case series have 2 decades of collective experience in performing and interpreting sialography. We emphasize its utility in diagnosing salivary gland pathologies, particularly benign ductal obstructions, structural deterioration in chronic sialadenitis, and autoimmune conditions. Sialography remains a benchmark approach for immediately revealing the etiology of undiagnosed benign glandular disorders, especially those originating from ductal pathologies [2,3].

Modern imaging techniques often struggle to detect peripheral ductal inconsistencies. Ultrasonography—the most widely used point-of-care (POCUS) tool—offers limited spatial resolution for intra-parenchymal ductal architecture. It has low sensitivity and a low negative predictive value for minute calcifications and mucus plugs [4,5]. In the authors’ experience, recurrent sialadenitis with unremarkable ultrasound findings is often underpinned by hidden ductal obstructions or architectural inconsistencies.

The cases documented here provide insight into ductal pathologies that were either underrepresented or undetected by ultrasound. Features such as strictures, irregular dilatations, tortuosity, and filling defects (representing calcific or mucinous blockages) were largely characterized as nonspecific sialadenitis on ultrasound. Furthermore, sialography clearly depicts the position of these defects relative to the hilum and the degree of acinar pooling. Therefore, unyielding glandular inflammation should be further investigated with sialography, preferably augmented by CBCT, CT, or MRI.

Each case underscores sialography’s value as an initial or adjuvant procedure. Case 1 highlights archetypal parenchymal sialectasis (acinar pooling), which prompted a diagnosis of Sjögren’s syndrome. The distribution of acinar pooling correlates with the extent of parenchymal destruction [6] and offers high sensitivity for autoimmune sialadenitis [7]. Subsequent cases involve ductal anomalies that remained unclear on ultrasound, including Case 5, which presents the first-ever sialographic documentation of Kussmaul disease characterized by acinar pooling and early sialodochitis.

While sialoendoscopy provides detailed, real-time visualization and minimally invasive intervention, its scope is limited by high costs, specialized training requirements, and limited availability. Our practice addressed these pitfalls by utilizing the diagnostic and marginal therapeutic aspects of sialography. Additionally, sialoendoscopy carries risks such as ductal perforation and may be hindered by a miniscule orifice (as seen in Case 2) or inaccessible higher-order branches [8,9]. Similarly, while MR Sialography is effective for stones and dilatations [2], its larger voxel resolution relative to CBCT may obscure terminal duct defects.

Conventional 2D sialography remains the most economical procedure, offering remarkable spatial resolution of the ductal anatomy. Although superimposition is an inherent limitation, it requires only a basic radiological setup and a trained clinician. By adhering to contraindications, the authors have observed no complications, though clinically significant inconsistencies are frequently discovered. CBCT-augmented sialography facilitates the most detailed visualization of the ductal system across orthogonal, oblique, and curved planes. Its isotropic voxel resolution and digital tools—such as image sharpening, contrast enhancement, digital subtraction, maximum intensity projections and segmented surface-rendered images (Figs. 1 and 4)—outperform both conventional and CT sialography [10,11]. High-resolution, small-FOV CBCT scans could radically transform diagnosis and serve as a “scout” for interventional sialoendoscopy, guiding surgeons with prior knowledge of the pathology's nature and severity. Furthermore, the “LSD” classification [12], used in two of our CBCT cases, provides a practical framework for the objective quantification of ductal variations.

Fig. 1.

(A) 3D rendition sialography of normal Submandibular gland clearly illustrating the course, curvature and calibre of Wharton's duct (1), the abrupt right-angled bend at the hilum (7) and the fine tributaries and network of peripheral ducts with acinar opacification (13) and (B) Segmented surface-rendered image of a parotid sialogram (Refer Table 1 for number legends)

Beyond diagnostics, sialography also provides therapeutic benefits. Moderate manual injection pressure facilitates ductal clearance by flushing out microbiota and mucus plugs, potentially dilating mild stenosis [13]. We have observed this effect in our practice; patients frequently report postprocedural pain reduction and increased salivation. Consequently, office-based sialography combined with retrograde ductal lavage can partially offset limited access to sialoendoscopy, providing symptomatic improvement and preventing unnecessary gland excision.

Limitations

The current study design limits the generalizability of sialography as a point-of-care procedure for benign salivary obstructions. To clarify its role in routine clinical practice, a controlled analysis is required to compare USG and Sialography in cases of chronic, unresponsive inflammation. By using sialoendoscopy as the gold standard, such a study would establish the definitive diagnostic efficacy of sialography for complex ductal pathologies.

Conclusion

The clinical insights presented here, although anecdotal, undoubtedly elucidate the unparalleled potential of sialography in the assessment of inflammatory salivary gland swellings of chronic nature. The authors explicitly recommend its utilization in clinical practice, particularly for unresponsive or recurrent sialadenitis with inconclusive ultrasound and limited access to sialoendoscopy. This practice could potentially reveal the occult inconsistencies of ducts in their entirety, thereby assisting in charting the optimum clinical approach for recurrent sialadenitis.

Patient consent

All 5 patients featured in this publication have provided informed consent for the inclusion of their clinical cases for case report containing radiological assessments only. Their anonymity has been fully preserved, and no personally identifiable radiographic images are presented.