Introduction: Salivary gland obstructive conditions are common and may necessitate imaging of the glands for diagnosis and management purposes. Many imaging options are available but all have limitations. Sialography is considered the gold standard for examining obstructive conditions of the parotid and submandibular glands but it is largely influenced by the imaging technique to which it is coupled. Cone beam computed tomography (cbCT) is a relatively new and very promising imaging modality that has overcome many of the inherent limitations of other imaging modalities used in the past for sialography. Materials and methods: A RANDO®Man imaging phantom was used to determine the effective radiation doses from the series of plain film images that represent the current standard of practice for sialography. Similar experiments were then undertaken to determine the effective radiation doses from cbCT when varying the field-of-view (FOV) size and center, x-ray tube peak kilovoltage (kVp) and milliamperage (mA). Next, cbCT image quality, measured using the signal-difference-to-noise-ratio (SDNR) was used to determine those technical factors that optimized image quality. Finally, using the optimized image acquisition parameters, a prospective clinical study was conducted to test the diagnostic efficacy of cbCT sialography compared to plain film sialography. Results: Effective radiation doses were comparable between the plain film image series and cbCT examinations of the parotid and submandibular glands when a 6” FOV was chosen, and when the x-ray tube was operating at 80 kVp and 10 mA. We also found that these exposure settings optimized the image SDNR. Finally, we demonstrated that the diagnostic capabilities of cbCT sialography were superior to plain film sialography with regards to detecting sialoliths and strictures, and when differentiating normal salivary glands from those with changes secondary to inflammation. Conclusion: We have successfully developed a three dimensional (3D) sialography technique for imaging the parotid and submandibular salivary glands using cbCT that balances radiation effective dose with image quality. We also demonstrated the superior diagnostic capabilities of the new technique in a clinical setting.

Introduction: Salivary gland obstructive conditions are common and may necessitate imaging of the glands for diagnosis and management purposes. Many imaging options are available but all have limitations. Sialography is considered the gold standard for examining obstructive conditions of the parotid and submandibular glands but it is largely influenced by the imaging technique to which it is coupled. Cone beam computed tomography (cbCT) is a relatively new and very promising imaging modality that has overcome many of the inherent limitations of other imaging modalities used in the past for sialography. Materials and methods: A RANDO®Man imaging phantom was used to determine the effective radiation doses from the series of plain film images that represent the current standard of practice for sialography. Similar experiments were then undertaken to determine the effective radiation doses from cbCT when varying the field-of-view (FOV) size and center, x-ray tube peak kilovoltage (kVp) and milliamperage (mA). Next, cbCT image quality, measured using the signal-difference-to-noise-ratio (SDNR) was used to determine those technical factors that optimized image quality. Finally, using the optimized image acquisition parameters, a prospective clinical study was conducted to test the diagnostic efficacy of cbCT sialography compared to plain film sialography. Results: Effective radiation doses were comparable between the plain film image series and cbCT examinations of the parotid and submandibular glands when a 6” FOV was chosen, and when the x-ray tube was operating at 80 kVp and 10 mA. We also found that these exposure settings optimized the image SDNR. Finally, we demonstrated that the diagnostic capabilities of cbCT sialography were superior to plain film sialography with regards to detecting sialoliths and strictures, and when differentiating normal salivary glands from those with changes secondary to inflammation. Conclusion: We have successfully developed a three dimensional (3D) sialography technique for imaging the parotid and submandibular salivary glands using cbCT that balances radiation effective dose with image quality. We also demonstrated the superior diagnostic capabilities of the new technique in a clinical setting.

Thesis (doctoral)--Lunds Universitet, Malmö 1984. / Extra t.p. with thesis statement inserted. Includes bibliographical references.

Hokkaido University (北海道大学) / 博士 / 医学

Abstract The purpose of the present study was to find reliable non-invasive methods for imaging salivary glands and diagnosing primary Sj?gren's syndrome (SS) and to evaluate autonomic function and central nervous system (CNS) disorders in patients with primary SS. The patient population consisted of consecutive patients with primary SS, who fulfilled the International classification criteria for primary SS, from the Division of Rheumatology, Department of Internal Medicine in Oulu University Hospital. Magnetic resonance (MR) imaging and MR sialography of parotid glands were performed on 27 patients and 7 healthy controls and ultrasonography (US) of major salivary glands on 27 patients, 27 healthy controls, and 27 symptomatic controls with sicca symptoms or salivary gland swellings without SS. MR imaging and US showed heterogeneous parenchyma or adipose degeneration of the gland in 81% and 78% of patients, respectively. MR sialography showed ductal system changes, narrowings and dilatations, or cavities in 96% of patients. One healthy control and 2 symptomatic controls had abnormal findings of parotid or submandibular glands on US. Other controls had normal findings. The diagnostic specificity of US was 94%. Parenchymal structural changes on MR imaging and US were associated with anti-Ro/SSA positivity and weakly with the focus score index, but not with salivary or tear secretion, age, disease duration, or features of systemic activity of the disease, such as hypergammaglobulinemia or systemic complications. A comprehensive package of cardiovascular tests, including 24-hour heart rate variability, baroreflex sensitivity test with phenylephrine, Valsalva manoeuvre, deep breathing tests, and active orthostatic test, were conducted on 30 patients and 30 healthy, age and sex-matched, randomly selected population-based controls. No signs of autonomic dysfunction were found in patients compared to controls in any of the tests. The test results were not associated with saliva or tear secretion, age, disease duration, or clinical features of systemic activity of the disease. A case of severe inflammatory CNS disease associated with primary SS was described, and an investigation of the relevant literature was made. Though inflammatory CNS disease is a possible complication of primary SS, there is no consensus regarding its prevalence or significance in the literature. Diagnostics and treatment are empiric. In conclusion, MR imaging, MR sialography, and US yield such a definitive picture of the glandular changes in primary SS that they are promising alternatives for invasive examinations in the diagnostics of primary SS. Comprehensive cardiovascular tests revealed no signs of autonomic dysfunction in patients with primary SS compared to general population.