Quantitative analysis of normal major salivary glands using computed tomography

Evaluation of the anterior processes of the parotid gland: an ultrasonographic study

OBJECTIVES

This study aimed to determine the prevalence of anterior extensions of the parotid gland (AEPG), namely the accessory parotid gland (APG) and the facial process of the parotid gland (FP), using ultrasonography.

STUDY DESIGN

A total of 338 parotid glands were scanned bilaterally. APG was defined as a soft tissue mass with the same echogenic features as the main parotid gland (MPG) and not in contact with it, while FP was defined as an extension that exceeded the anterior border of the mandibular ramus and was continuous with the MPG. The anteroposterior, mediolateral, superoinferior dimensions and the mean distance from the MPG to the APG were measured.

RESULTS

The prevalence of APG and FP were 19.5% and 36%, respectively, resulting in an AEPG prevalence of 55.6%. The presence of APG was statistically higher in females than in males (p = 0.039). The mean anteroposterior, mediolateral, and superoinferior dimensions of the APG were 18.1 ± 0.57 mm, 0.35 ± 0.17 mm, and 12.3 ± 0.36 mm, respectively, and the mean distance from the MPG was measured as 12.1 ± 0.87 mm.

CONCLUSION

This study can raise awareness among clinicians about the presence of AEPG in the differential diagnosis of mid-cheek masses.

Population Based Average Parotid Gland Volume and Prevalence of Incidental Tumors in T1-MRI

Representative epidemiologic data on the average volume of the parotid gland in a large population-based MRI survey is non-existent. Within the Study of Health in Pomerania (SHIP), we examined the parotid gland in 1725 non-contrast MRI-scans in T1 weighted sequence of axial layers. Thus, a reliable standard operating procedure (Intraclass Correlation Coefficient > 0.8) could be established. In this study, we found an average, single sided parotid gland volume of 27.82 cm3 (95% confidence interval (CI) 27.15 to 28.50) in male and 21.60 cm3 (95% CI 21.16 to 22.05) in female subjects. We observed positive associations for age, body mass index (BMI), as well as male sex with parotid gland size in a multivariate model. The prevalence of incidental tumors within the parotid gland regardless of dignity was 3.94% in the Northeast German population, slightly higher than assumed. Further epidemiologic investigations regarding primary salivary gland diseases are necessary.

Age-Related Changes in the Submandibular Gland: An Imaging Study of Gland Ptosis Versus Volume

BACKGROUND

Debate surrounding the morphological evolution of the submandibular gland (SMG) with aging, and the uncertain influence of patient demographics, has led to hesitancy about incorporating targeted interventions of the SMG into clinical practice.

OBJECTIVES

The aim of this study was to determine whether SMG ptosis, hypertrophy, or both is the primary etiology behind the increase in submandibular volume with age.

METHODS

MRI segmentation was used to calculate the total and inframandibular (IM) volume and height of the SMG. Adult subjects with previous MRIs of the head and neck were used for analysis. Those with pathology or artifact compromising the SMG were excluded. Subjects were divided into 4 age-defined cohorts, for clinical applicability.

RESULTS

The study included 129 patients (65 females; 64 males) with a mean age of 52.3 years (range, 20-85 years). No significant change in total SMG volume was observed between the reference group and all cohorts. The IM-SMG volume of the reference cohort was 5.77 cm3. All 3 cohorts had a greater IM-SMG volume than the reference group. The 45- to 54-year cohort had a mean volume of 6.7 cm3 (P = 0.4), the 55- to 64-year cohort, 7.5 cm3 (P = 0.01), and the ≥65-year cohort, 7.2 cm3 (P = 0.01). Male sex and overweight or obese BMI were associated with significantly larger total and IM-SMG volumes.

CONCLUSIONS

The novel finding of a significantly larger IM-SMG volume with no change in total volume provides evidence for SMG ptosis rather than hypertrophy as a significant contributor to age-related submandibular fullness. The lack of any significant difference in total volume or height with aging emphasizes the role of glandular descent.

Establishing correlations between normal pancreatic and submandibular gland ducts

Background

The objectives of this study were to evaluate the relationship between ductal morphometry and ramification patterns in the submandibular gland and pancreas in order to validate their common fractal dimension.

Methods

X-ray ductography with software-aided morphometry were obtained by injecting barium sulphate in the ducts of post-mortem submandibular gland and pancreas specimens harvested from 42 adult individuals.

Results

Three cases were excluded from the study because of underlying pathology. There was a significant correlation between the length of the main pancreatic duct (MPD) and the intraglandular portion of the right submandibular duct (SMD) (r = 0.3616; p = 0.028), and left SMD (r = 0.595; p < 0.01), respectively, but their maximal diameters did not correlate (r = 0.139—0.311; p > 0.05). Both dimensions of the SMD showed a significant right-left correlation (p < 0.05). The number of MPD side branches (mean = 37) correlated with the number of side branches of left SMD, but not with the right one (mean = 9). Tortuosity was observed in 54% of the MPD, 32% of the right SMD, and 24% of the left SMD, with mutual association only between the two salivary glands.

Conclusions

Although the length of intraglandular SMD and MPD correlate, other morphometric ductal features do not, thus suggesting a more complex relationship between the two digestive glands.

Clinical and histopathologic characteristics of submandibular gland in Stevens-Johnson syndrome: A comparative study

OBJECTIVE

The objective of this study was to investigate the clinical manifestations and pathologic appearances of the submandibular gland (SMG) in Stevens-Johnson syndrome (SJS).

STUDY DESIGN

Patients with autologous transplantation of SMG for treatment of severe dry eye between March 1998 and May 2018 were divided into the SJS group (70 cases) and non-SJS group (50 cases) according to the history of SJS. The SMG weight and computed tomography volume and salivary flow rate were measured. The concentration index and secretion index were estimated using scintigraphy with technetium-99m-pertechnetate. Histopathology studies of SMG tissues were conducted, and the acini parameters were measured using a digital image analyzer.

RESULTS

A decreased computed tomography volume and weight was observed in 48.57% the SJS group and 2% in the non-SJS group (P < .01). The rest whole, acid-stimulated whole, and SMG rest salivary flow rates decreased in the SJS group (P < .05). The normal SMG concentration index (37.5% vs 96.67%, P < .001) and secretion index (35% vs 96.67%, P < .001) rates were lower in the SJS group than in the non-SJS group. The glandular parenchyma was reduced, the acinar space was widened, and the fat content was increased in the SJS group.

CONCLUSION

SMG atrophic and degenerative changes occurred in the SJS group, with a decrease in salivary secretion function in more than half of the patients.

The Submandibular Gland and The Aging Neck: A Longitudinal Volumetric Study

INTRODUCTION

The true effect of aging and other patient factors on submandibular gland (SMG) volume is unclear. We sought to evaluate the effects of age, body mass index (BMI), sex and race on SMG volume using computed tomography (CT) imaging.

METHODS

We conducted a retrospective longitudinal study of adult subjects with multiple CT images of the neck at least 7 years apart. Subjects with history of salivary gland pathology, neck dissection, head and neck radiation, active infection or dental artifact were excluded. Three-dimensional volumes were measured. Age, BMI, sex and race data were analyzed to track their longitudinal effect on SMG volume.

RESULTS

The study comprised 64 patients (Females n=36; Males n=28) with mean age of 47.1 and 58.5 at each respective time point (mean difference 11.4). Mean SMG volume increased from 10.1 ml to 10.5 ml (P < 0.05). Males had significantly greater SMG volume compared to females. Majority of growth occurred in the < 40 year age bracket (0.1 ml/year), more significantly in the male cohort. When controlling for aging and sex, a change in BMI was the only patient factor that predicted a change in SMG volume. An increase of 1.0 kg/m² predicted a 0.17 ml increase in gland volume. Race had no significant effect.

CONCLUSION

Our findings suggest that the majority of SMG volume change occurs in early adulthood ( < 40 years), especially in males. Among the factors we studied, a change in BMI was the only significant predictor of SMG volume change.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 . Genital Surgery.

The Aging Parotid Gland: A Longitudinal Volumetric Study and Implications for Treatment

BACKGROUND

The parotid gland accounts for significant soft tissue volume in the face and is therefore of central relevance to facial and neck rejuvenation.

OBJECTIVES

The aim of this study was to determine how parotid gland volume is predicted by age and other factors.

METHODS

We conducted a retrospective longitudinal study of patients with multiple computed tomography (CT) scans of the neck performed at least 7 years apart. Parotid gland volumes were measured and multiple linear regression analysis was performed to model the relations between age, body mass index (BMI), and parotid volume.

RESULTS

The study cohort comprised 70 patients. The mean [standard deviation] ages at initial and final imaging time points were 47.5 [12.6] and 58.8 [12.2] years, respectively, with an average of 11.3 years elapsed between CT scans. The mean parotid gland volume increased from 28.7 [10.0] to 32.2 [10.7] mL over the average 11.3-year period (P = 0.03). However, the results of the multiple linear regression analysis show that when controlling for BMI and sex, age alone does not predict parotid volume (P = 0.29). BMI was directly correlated with gland volume (P < 0.01). An increase of 1.0 kg/m2 in BMI predicted an increase in parotid volume by 1.1 mL. Male sex was also associated with significantly greater parotid volume.

CONCLUSIONS

Mean parotid volume increased over time but these gains were driven by increases in BMI and not age alone. These findings are highly relevant to the treatment of the aging face and neck.

Enhanced Salivary and General Oxidative Stress in Hashimoto's Thyroiditis Women in Euthyreosis

Hashimoto’s thyroiditis (HT) is one of the most common autoimmune diseases. Although HT is inextricably linked to oxidative stress, there have been no studies assessing salivary redox homeostasis or salivary gland function in patients with HT. This study is the first to compare antioxidant defense and oxidative stress biomarkers in non-stimulated (NWS) and stimulated (SWS) whole saliva and plasma/erythrocytes of HT patients compared to controls. The study included 45 women with HT in the euthyreosis period as well as an age- and gender-matched control group. We showed that NWS secretion was significantly lower in HT patients compared to healthy controls, similar to salivary amylase activity in NWS and SWS. Catalase and peroxidase activities were considerably higher in NWS and SWS of HT patients, while the concentrations of reduced glutathione and uric acid were significantly lower in comparison with healthy subjects. Total antioxidant potential was significantly lower, while total oxidant status and the level of oxidation products of proteins (advanced glycation end products, advanced oxidation protein products) and lipids (malondialdehyde, lipid hydroperoxides) were significantly higher in NWS, SWS and plasma of HT patients. In conclusion, in both salivary glands of women with HT in euthyreosis, the ability to maintain redox homeostasis was hindered. In HT patients we observed oxidative damage to salivary proteins and lipids; thus, some biomarkers of oxidative stress may present a potential diagnostic value.

Comparison of Clinical Characteristics and Magnetic Resonance Imaging of Salivary Glands With Magnetic Resonance Sialography in Sjögren's Syndrome

OBJECTIVES/HYPOTHESIS

To compare the results of magnetic resonance imaging with magnetic resonance sialography (MRSIAL) and the clinical and laboratory characteristics in a well-characterized cohort of patients with primary or secondary Sjögren's syndrome (SS) meeting the American-European Consensus Group criteria.

STUDY DESIGN

Retrospective, observational, monocentric study.

METHODS

Thirty-six patients (81% female, mean age = 48 ± 35 years) with primary or secondary SS who underwent MRSIAL were included in the study.

RESULTS

MRSIAL revealed characteristic radiological signs in the parotid, sublingual, and submandibular salivary glands in 35/36 patients (97%). Patients presenting with anti-Sjögren's syndrome-related antigen A (SSA) autoantibodies showed more often fatty infiltration, a "pepper-and-salt" appearance, ductal stenosis, and/or ductal dilation of the parotid gland (88%, 88%, and 72% respectively) than patients negative for anti-SSA (12%, 4%, and 28% respectively). MRSIAL demonstrated signs characteristic of SS in all 11 patients with negative minor salivary gland biopsy. For 15 patients undergoing ultrasound examination only, 11 (73%) had SS findings, but all 15 had SS findings on MRSIAL. Two cases of parotid lymphoma were detected by MRSIAL (6%).

CONCLUSIONS

MRSIAL is a reliable technique to detect glandular anomalies in patients with SS, and seems to provide a valuable aid in the diagnosis of SS.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E83-E89, 2021.

Enhanced Inflammation and Nitrosative Stress in the Saliva and Plasma of Patients with Plaque Psoriasis

Psoriasis is the most common inflammatory skin disease, characterized by the release ofproinflammatory cytokines from lymphocytes, keratinocytes, and dendritic cells. Although psoriasis is considered an immune-mediated inflammatory disease, its effect on secretory activity of salivary glands and quantitative composition of saliva is still unknown. The aim of this study was to evaluate the secretion of saliva as well as several selected inflammation and nitrosative stress biomarkers in unstimulated and stimulated saliva as well as plasma of psoriasis patients. We demonstrated that, with progressing severity and duration of the disease, the&nbsp; secretory function of the parotid and submandibular salivary glands is lost, which is&nbsp; manifested as decreased unstimulated and stimulated saliva secretion and reduced salivary amylase activity and total protein concentration. The levels of tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL-2), and interferon-gamma (INF-α) were significantly higher, whereas interleukin-10 (IL-10) content was considerably lower in unstimulated and stimulated saliva of patients with psoriasis compared to the controls, and the changes increased with the disease duration. Similarly, we observed that the intensity of nitrosative stress in the salivary glands of psoriasis patients depended on the duration of the disease. By means of receiver operating characteristic (ROC) analysis, we showed that the evaluation of nitric oxide (NO), nitrotyrosine, and IL-2 concentration in non-stimulated saliva with high sensitivity and specificity differentiatedpsoriasis patients on the basis of the rate of saliva secretion (normal salivation vs. hyposalivation). In summary, the dysfunction of salivary glands in psoriasis patients is caused by inflammation and nitrosative stress.

Dysfunction of Salivary Glands, Disturbances in Salivary Antioxidants and Increased Oxidative Damage in Saliva of Overweight and Obese Adolescents

Obesity is inseparably connected with oxidative stress. This process may disturb the functioning of the oral cavity, although the effect of oxidative stress on salivary gland function and changes in the qualitative composition of saliva are still unknown. Our study is the first to evaluate salivary redox homeostasis in 40 overweight and obese adolescents and in the age- and gender-matched control group. We demonstrated strengthening of the antioxidant barrier (superoxide dismutase, catalase, peroxidase, uric acid, total antioxidant capacity (TAC)) with a simultaneous decrease in reduced glutathione concentration in saliva (non-stimulated/stimulated) in overweight and obese teenagers compared to the controls. The concentration of the products of oxidative damage to proteins (advanced glycation end products), lipids (malondialdehyde, 4-hydroxynonenal) and DNA (8-hydroxydeoxyguanosine) as well as total oxidative status were significantly higher in both non-stimulated and stimulated saliva as well as plasma of overweight and obese adolescents. Importantly, we observed more severe salivary and plasma redox alterations in obese adolescents compared to overweight individuals. In the study group, we also noted a drop in stimulated salivary secretion and a decrease in total protein content. Interestingly, dysfunction of parotid glands in overweight and obese teenagers intensified with the increase of BMI. We also showed that the measurement of salivary catalase and TAC could be used to assess the central antioxidant status of overweight and obese adolescents.

Planimetric correlation between the submandibular glands and the pancreas: a postmortem ductographic study

The salivary glands and pancreas have comparable anatomic and antigenic properties and can share common pathogenetic mechanisms involving toxic or autoimmune processes. The aim of this study is to assess the correlation in size between the normal submandibular glands and the pancreas. The study was based on human autopsy specimens of the pancreas, neck and oral base from 22 adults, both sexes (mean age, 57.9 years). The pancreatic and submandibular ducts were injected with a contrast medium, and the area of the salivary and pancreatic glandular ductograms was measured with the aid of software for quantification of visual information. Samples of tissue from the salivary glands and the pancreas were studied by means of light microscopy. A high correlation was found between the planimetric size of the pancreas and the submandibular glands (correlation coefficient 0.497 and 0.699 for the right and the left gland, respectively). This ratio was close to 5:1. There were no significant differences in size for the left vs. right submandibular gland (p = 0.39). The ductograms were significantly larger in size in males than in females (p < 0.001). This study has proven a positive correlation in planimetric size between the normal submandibular glands and pancreas, a result that is expected to have possible clinical implications in the long-term follow-up of patients with chronic pancreatitis.

Radiation-induced CT number changes in GTV and parotid glands during the course of radiation therapy for nasopharyngeal cancer

OBJECTIVE

To investigate the changes in CT number (CTN) in gross tumour volume (GTV) and organs at risk (OARs) during the course of radiation therapy (RT) for nasopharyngeal cancer (NPC).

METHODS

Daily megavoltage CT (MVCT) data collected from 30 patients with NPC treated with a prescription dose of 70 Gy in 30-33 fractions using helical tomotherapy were retrospectively analyzed. The contours of GTV and OARs on daily MVCTs were obtained by populating the planning contours from planning CT to daily MVCTs with manual editing, if necessary. The changes of GTV and OAR volumes and the histograms of CTN in the GTV and OARs during the course of RT delivery were analyzed.

RESULTS

Volumes of GTV and parotid glands were reduced during the course of radiation treatment, with an average shrinkage rate of 0.23% per day (range, 0.02-0.8%) and 1.2% per day (range, 0.2-2.3%), respectively. The mean CTN changes in GTV and ipsilateral and contralateral parotid glands were reduced by 52 ± 35 HU, 18 ± 20 HU and 17 ± 22 HU, respectively. For GTV, the CTN and GTV volume decreases were found to be correlated with each other (p < 0.0001). No noticeable CTN change was found in the spinal cord and non-specified tissue irradiated with low doses.

CONCLUSION

The CTN changes in GTV and parotids are measurable during the delivery of fractionated radiotherapy for NPC, were associated with the doses received (the number of fractions delivered) and were patient specific.

ADVANCES IN KNOWLEDGE

The CTN change during radiotherapy is dose dependent and is measurable for NPC.

Optical Coherence Tomography of the Labial Salivary Glands Reveals Age-Related Differences in Women

The labial minor salivary glands (LSGs) play a role in medical research and practice due to their superficial location and involvement in both systemic and localized diseases. Swept-source optical coherence tomography (OCT) is a noninvasive modality that enables in vivo, micrometer resolution, wide-field three-dimensional imaging in seconds. A purpose-built swept-source OCT instrument was employed to acquire three-dimensional datasets covering the area of 2.43 cm(2) of the mucosa of the lower lip to the depth of 3.4 mm in young (n = 14; mean age ± SD: 27 ± 3 years; body mass index [BMI] 20.4 ± 2.3 kg/m(2) ) and middle-aged women (n = 11; 54 ± 6 years; 25.5 ± 3.2 kg/m(2) ). Glandular tissue reflectivity mode (range 0-255; 86 ± 17 vs. 68 ± 12, p = 0.005), average single LSG area in tissue sample (5.26 ± 2.62 mm(2) vs. 2.87 ± 1.26 mm(2) , p = 0.011), and LSG surface filling factor (0.23 ± 0.13 vs. 0.11 ± 0.10, p = 0.027) had higher values in younger than in middle-aged women. A correlation between BMI and glandular tissue reflectivity mode (Spearman's ρ = -0.60) was found (p = 0.002). The results highlight the potential value of LSGs' OCT morphometry in research regarding ageing.

Computed tomography number changes observed during computed tomography-guided radiation therapy for head and neck cancer

PURPOSE

To investigate CT number (CTN) changes in gross tumor volume (GTV) and organ at risk (OAR) according to daily diagnostic-quality CT acquired during CT-guided intensity modulated radiation therapy for head and neck cancer (HNC) patients.

METHODS AND MATERIALS

Computed tomography scans acquired using a CT-on-rails during daily CT-guided intensity modulated radiation therapy for 15 patients with stage II to IVa squamous cell carcinoma of the head and neck were analyzed. The GTV, parotid glands, spinal cord, and nonspecified tissue were generated on each selected daily CT. The changes in CTN distributions and the mean and mode values were collected. Pearson analysis was used to assess the correlation between the CTN change, organ volume reduction, and delivered radiation dose.

RESULTS

Volume and CTN changes for GTV and parotid glands can be observed during radiation therapy delivery for HNC. The mean (±SD) CTNs in GTV and ipsi- and contralateral parotid glands were reduced by 6 ± 10, 8 ± 7, and 11 ± 10 Hounsfield units, respectively, for all patients studied. The mean CTN changes in both spinal cord and nonspecified tissue were almost invisible (<2 Hounsfield units). For 2 patients studied, the absolute mean CTN changes in GTV and parotid glands were strongly correlated with the dose delivered (P<.001 and P<.05, respectively). For the correlation between CTN reductions and delivered isodose bins for parotid glands, the Pearson coefficient varied from -0.98 (P<.001) in regions with low-dose bins to 0.96 (P<.001) in high-dose bins and were patient specific.

CONCLUSIONS

The CTN can be reduced in tumor and parotid glands during the course of radiation therapy for HNC. There was a fair correlation between CTN reduction and radiation doses for a subset of patients, whereas the correlation between CTN reductions and volume reductions in GTV and parotid glands were weak. More studies are needed to understand the mechanism for the radiation-induced CTN changes.

Salivary glands of healthy children versus sialorrhea children, is there an anatomical difference? An ultrasonographic biometry

OBJECTIVES

There is no literature about the average size of the salivary glands in the pediatric population with drooling (sialorrhea). Studies have shown that some pathologies affect the functionality of the salivary glands. We assessed via ultrasonography the sizes of the submandibular and parotid glands in 9 healthy children who were not suffering from local or systemic diseases that could affect the salivary glands. We also compared this group with a group of 9 patients with sialorrhea.

METHODS

Volunteers were matched based on age, gender, and BMI. Body weight did not differ more than 20% from ideal weight. The parotid and submandibular glands of 9 patients with sialorrhea without any previous treatment were measured via ultrasound and matched to a healthy control. Children with various causes for drooling were included (neurological disorders, neuromuscular disorders, lack of oral motor control).

RESULTS

Dimensions of the parotid glands in drooling and healthy patients were: surface area 2.96 cm(2) (SD ±0.90) and 2.81 cm(2) (SD ±0.54); in depth 1.68 cm (SD ±0.24) and 1.61 cm (SD ±0.27); in the axis longitudinal to the horizontal mandibular ramus 3.18 cm (±0.46) and 3.15 cm (SD ±0.45) in drooling and healthy groups respectively. The means of submandibular glands of drooling and healthy patients measured in surface area: 3.20 cm(2) (SD ±0.66) and 3.08 cm(2) (SD ±0.65); anterior-posterior length 1.55 cm (SD ±0.23) and 1.46 cm (SD ±0.23), medio-lateral length 3.07 cm (SD ±0.39) and 3.07 cm (SD ±0.32). There was no statistical significance in comparison with the healthy group control.

CONCLUSION

The parotid and submandibular salivary glands in the pediatric population do not differ in size in children with or without drooling. Measuring the glands at baseline and post treatment with botulinum toxin injections allows one to evaluate if there are changes in the gland related to the treatment.

Changes in parotid gland morphology and function in patients treated with intensity-modulated radiotherapy for nasopharyngeal and oropharyngeal tumors

OBJECTIVE

To evaluate the morphological changes of the parotid glands in patients treated with intensity-modulated radiotherapy (IMRT) for nasopharyngeal and oropharyngeal tumors and the correlations with parotid function.

METHODS

Ten patients with nasopharyngeal and oropharyngeal tumors treated with IMRT between May 2009 and January 2010 at Hokkaido University Hospital were included in this study. In the morphological assessment of the parotid glands, the sizes and computed tomography (CT) numbers of the bilateral parotid glands before and after IMRT with CT were calculated. For functional assessment of the parotid glands, we conducted the Saxon test and used a visual analog scale (VAS) for xerostomia evaluation.

RESULTS

Reductions in saliva secretion were observed in the patients treated with IMRT for nasopharyngeal and oropharyngeal tumors, and there was a significant correlation between the reduction in saliva secretion and the VAS. The reductions in the parotid gland size and CT number were larger on the ipsilateral side than on the contralateral side. The reduction in saliva secretion was not significantly correlated with the reduction in parotid gland size, but was significantly correlated with the reduction in CT number.

CONCLUSIONS

Morphological and functional changes of the parotid glands were observed after IMRT for nasopharyngeal and oropharyngeal tumors, and preservation of the contralateral parotid glands was only partly achieved. Among the morphological changes of the parotid glands, the CT number may be considered a predictor of parotid function after radiotherapy.

Age-related relaxo-volumetric quantitative magnetic resonance imaging of the major salivary glands

OBJECTIVE

To study age-related characteristics of T1 and T2 relaxation times and volume of the major salivary glands.

METHODS

Thirty-five subjects (0.5-87 years old) with normal salivary glands were imaged with mixed turbo spin-echo pulse sequences at 1.5-T magnetic resonance units. Bilateral parotid, submandibular, and sublingual glands were segmented manually. Histograms for each salivary gland were generated and modeled with Gaussian functions for every parameter.

RESULTS

Seventy parotid glands, 52 submandibular glands, and 50 sublingual glands were segmented and the histograms were analyzed. The parotid gland exhibited shorter-peak T1s and longer-peak T2s relative to the submandibular and sublingual glands. The peak T2s for all glands showed a minimum value between 2 and 4 years of age and increased monotonically thereafter. From birth to early adulthood, all glands increased in size logarithmically.

CONCLUSION

Age-related relaxo-volumetric changes of the major salivary glands show clear T2 and volumetric age-related patterns for all glands.

Effect of botulinum toxin type a on morphology of salivary glands in patients with cerebral palsy

Objective

To investigate the effect of botulinum toxin type A (BTXA) on drooling and the morphologic change of the salivary gland in patients with cerebral palsy.

Method

Eight cerebral palsy patients suffering from severe drooling participated in this study. BTXA was injected into both submandibular and parotid glands under intravenous sedation and with ultrasound guidance (1 unit/gland/kg: maximum 100 units) in an outpatient or inpatient procedure. The severity of drooling was measured before injection and 3 weeks after injection using the Teacher Drooling Scale, the Drooling Score-severity, frequency and the Visual Analog Scale. To investigate the morphologic change of the salivary glands, the size of salivary glands were measured before injection and 3 weeks after injection using computed tomography of the neck. The measurement values were analyzed by Wilcoxon signed rank test.

Results

Statistically significant improvements were shown in all three parameters for assessing the severity of drooling after BTXA injections (p<0.05). Size of the salivary glands were significantly decreased at 3 weeks after BTXA injection (p<0.05).

Conclusion

Salivary gland injection with BTXA could be a useful treatment method to reduce drooling in patients with cerebral palsy and decreased size of salivary glands may partially explain the mechanism.

Assessment of post-radiotherapy salivary glands

Salivary glands are usually irradiated during radiotherapy for head and neck cancers, which can lead to radiation-induced damage. Radiation-induced xerostomia (oral dryness) is the most common post-radiotherapy complication for head and neck cancer patients and can reduce the patient's quality of life. Accurate and efficient salivary gland assessment methods provide a better understanding of the cause and degree of xerostomia, and may help in patient management. At present, there are different methods for the assessment of salivary gland hypofunction; however, none of them are considered to be standard procedure. This article reviews the value of common methods in the assessment of post-radiotherapy salivary glands.

Association between obesity, flow rate of whole saliva, and dental caries in adolescents

In a cross-sectional study design, we test the hypothesis whether childhood obesity is associated with reduced flow rate of stimulated whole saliva and dental caries. Obese adolescents (n = 65) with a mean age of 14.5 years and normal weight subjects (n = 65) with a mean age of 14.2 years were clinically examined with respect to dental caries, visible plaque accumulation (visible plaque index (VPI%)), gingival inflammation in terms of bleeding on probing (BOP%) as well as answered a questionnaire concerning medical history, medication, oral hygiene habits, smoking habits, and sociodemographic background. The flow rate of stimulated whole saliva (ml/min) was determined. BMI was calculated and adjusted for age and gender (BMI-sds). The obese subjects exhibited higher number of decayed surfaces (DS), 0.7 vs. 0.1 (P = 0.008) and lower flow rate of stimulated whole saliva 1.2 vs. 2.0 ml/min (P < 0.001). Of obese patients, 17 subjects had VPI% >25 and 21 had BOP% >25, both compared to only 5 subjects of the normal weight with P values of 0.005 and <0.001, respectively. In a multivariate logistic regression model BMI-sds was significantly associated with the flow rate of stimulated whole saliva less than the median value 1.5 ml/min (P < 0.001; odds ratio (OR) 1.36) as well as with DS (DS >0) (P = 0.002; OR 1.31) and the associations were not found to be confounded by any of the studied variables. The results indicate that childhood obesity is associated with reduced flow rate of stimulated whole saliva and dental caries and further strengthens obesity's negative effect on children's oral health.

Anatomical localization of submandibular gland for botulinum toxin injection

The aim of this study was to document the anatomical landmarks of the submandibular gland (SMG) for a botulinum toxin injection. Thirty-four SMGs from 20 cadavers were examined. The mean length of a reference line between the angle of the mandible and the gnathion was 94.8 ± 5.9 mm, the proximal and distal point of the SMG from the angle of the mandible was 10.6% (11.5 ± 3.5 mm) and 41.8% (40.9 ± 5.2 mm), respectively. The facial artery came out of the SMG at 11.6% (14.6 ± 3.4 mm) and the position of the intersection of the facial artery with the inferior border of the mandible was located at 24.4% (28.0 ± 5.5 mm) from the angle of the mandible. The shape of the SMG was generally triangular or irregular round on the anatomical position. The mean superior-inferior diameter, anterior-posterior diameter and medial-lateral diameter of the gland was 28.8 ± 4.1, 30.0 ± 6.1 and 15.1 ± 3.5 mm, respectively. The safety zone for the injection was 20-35% from the mandible angle on the inferior view and 1.5 cm below the inferior line of the mandible on the lateral view. In addition, the needle should be inserted to a depth of 2.0 cm from the skin surface on the inferior view. These results may assist in determining a accurate localization of injection sites for the SMG, particularly for injections without ultrasound guidance.

Anterior mandibular lingual salivary gland defect: A report of a case diagnosed with cone-beam computed tomography and magnetic resonance imaging

Anterior mandibular lingual salivary gland defects are rare. They may be evident on routine radiographic exam. Because the differential diagnosis can be exhaustive, differential interpretation and diagnosis are crucial. A case of large bilateral radiolucent lesions of the anterior mandible that was an anterior mandibular salivary gland defect is reported in a young female. This lesion was initially visualized on a panoramic radiograph. Further evaluation was undertaken with dental cone-beam computed tomography. Confirmation of bilateral anterior mandibular lingual salivary gland defects was made using magnetic resonance imaging, negating the need for surgical biopsy.

Assessment of age-related morphological and functional changes of selected structures of the head and neck by computed tomography, magnetic resonance imaging, and positron emission tomography

The head and neck is a complex anatomical region that can be evaluated using many imaging modalities. It is important to discern normal structures from ones that are affected by disease and to study how these structures change in their morphological and functional properties with aging. Therefore, using magnetic resonance imaging (MRI), we retrospectively evaluated volumes of the parotid glands, submandibular glands, thyroid gland, tongue, soft palate, and lingual tonsils in 64 subjects ages 13 to 81 years. Volume, attenuation (HU), and metabolic activity (maximum SUV) of the parotid, submandibular, and thyroid glands were assessed retrospectively using positron emission tomography/computed tomography (PET/CT) imaging in 35 subjects ages 10 to 76 years. Metabolic activity (maximum SUV) of the parotid, submandibular, and sublingual glands; tongue; adenoids; and tonsils (lingual and palatine) were evaluated retrospectively using PET imaging in 15 subjects ages 6 to 20 years. Metabolic volumetric products of the parotid, submandibular, and thyroid gland were calculated and analyzed with increasing age in subjects who underwent PET/CT imaging. Structures that exhibited statistically significant changes (P < 0.05) with increasing age included the submandibular glands, thyroid gland, soft palate, and adenoids. The CT volume of the submandibular glands increased with age, and the attenuation decreased with age with statistical significance. The thyroid gland volume, as measured using MRI, showed a statistically significant decrease with aging. The volume of the soft palate and lingual tonsils, as measured by MRI, exhibited a statistically significant decrease in volume with aging. The maximum SUV of the adenoids demonstrated a statistically significant decrease with aging. In conclusion, CT, MRI, and PET may be used to quantitatively and qualitatively assess structures of the head and neck and are useful in the assessment of structural and functional changes of these structures with aging.

Influence of intravenous contrast agent on dose calculations of intensity modulated radiation therapy plans for head and neck cancer

BACKGROUND AND PURPOSE

To evaluate the effect of an intravenous contrast agent (CA) on dose calculations and its clinical significance in intensity modulated radiation therapy (IMRT) plans for head and neck cancer.

MATERIALS AND METHODS

Fifteen patients with head and neck cancer and involved neck nodes were enrolled. Each patient took two sets of computerized tomography (CT) in the same position before and after intravenous CA injections. Target volumes and organs at risk (OAR) were contoured on the enhanced CT, and then an IMRT plan of nine equiangular beams with a 6 MV X-ray was created. After the fusion of non-enhanced and enhanced CTs, the contours and the IMRT plan created from the enhanced CT were copied and placed to the non-enhanced CT. Doses were calculated again from the non-enhanced CT by the same IMRT plan. The radiation doses calculated from the two sets of CTs were compared with regard to planning target volumes (PTV) and the three OARs, both parotid glands and the spinal cord, by Wilcoxon's signed rank test.

RESULTS

The doses (maximum, mean, and the dose of 95% of PTV received (D95%)) of PTV70 and PTV59.4 calculated from the enhanced CTs were lower than those from the non-enhanced CTs (p < 0.05), but the dose differences were less than 1% compared to the doses calculated from the enhanced CTs. The doses of PTV50.4, parotid glands, and spinal cord were not significantly different between the non-enhanced and enhanced CTs.

CONCLUSIONS

The difference between the doses calculated from the CTs with and without CA enhancement was tolerably small, therefore using intravenous CA could be recommended for the planning CT of head and neck IMRT.

Symmetry of the submandibular glands in humans—a postmortem study assessing the linear morphometric parameters

BACKGROUND

The analysis of morphometric right-left symmetry of the salivary glands is important for assessing unilateral changes discovered in these organs during diagnostic imaging.

STUDY DESIGN

A study was carried out on 18 adult human autopsy neck and maxillofacial specimens from both sexes (14 males, 4 females), with age range of 17 to 73 years (mean age 49.9 years). The submandibular duct was injected with contrast medium and images were made in two projection planes.

RESULTS

Morphometry performed using the obtained radiographs included: (a) caliber (mean proximal, middle, and distal = 1.73 mm, 1.82 mm, and 1.77 mm), (b) length (mean = 37.2 mm); (c) genu of the submandibular duct (mean = 114 degrees ); and (d) longitudinal and transverse diameters of the gland (mean = 44.1 mm and 25.9 mm). Comparison of these morphometric parameters between the right and the left glands revealed no statistically significant differences.

CONCLUSION

There is a high level of right-left symmetry in linear morphometric parameters of the submandibular gland.