Can the function of the tubarial glands be evaluated using [99mTc]pertechnetate SPECT/CT, [18F]FDG PET/CT, and [11C]methionine PET/CT?

Maximum standardized uptake value for parotid and submandibular glands in patients with Sjögren's syndrome and submandibular sialolithiasis using salivary gland SPECT/CT

Recently, SPECT/CT plays an important role in assessing patients with head and neck lesions. The aim of this study was performed to investigate the maximum standardized uptake value (SUVmax) for parotid and submandibular glands in patients with Sjögren's syndrome and submandibular sialolithiasis using salivary gland SPECT/CT. A prospective study was performed in 45 patients with 32 Sjögren's syndrome and 13 submandibular sialolithiasis who underwent salivary gland SPECT/CT. The SUVmax of parotid and submandibular glands was obtained using a workstation and software. The salivary secretion function of parotid and submandibular glands was defined as ratio of pre- to post-stimulation on SUVmax. A p value lower than 0.05 was considered as statistically significant. The SUVmax for parotid glands in patients with Sjögren's syndrome at pre-stimulation (18.0 ± 14.3), post-stimulation (12.0 ± 9.4), and ratio of pre- to post-stimulation (1.46 ± 0.52) were significantly lower than those of submandibular sialolithiasis (44.9 ± 8.4 (p < 0.001), 17.8 ± 6.5 (p < 0.001), and 2.75 ± 0.79 (p < 0.001), respectively). The SUVmax for submandibular glands in patients with Sjögren's syndrome at pre-stimulation (16.9 ± 18.7) were significantly lower than those with sialolithiasis (36.7 ± 27.8, p = 0.004) and without sialolithiasis (39.7 ± 16.0, p = 0.001) in patients with submandibular sialolithiasis. The salivary gland SPECT/CT SUVmax can be useful in clinical practice for the quantitative management of parotid and submandibular glands in patients with Sjögren's syndrome and submandibular sialolithiasis.

A Prospective Evaluation of Tubarial Gland Doses With Acute Dysphagia and Treatment Tolerance in Head and Neck Cancer Patients

Background This study prospectively analyzed the clinical significance of tubarial glands (TGs) doses in head and neck cancer (HNC) patients. Methods Patients diagnosed with HNC in Ankara Bilkent City Hospital, Turkey were analyzed. TGs volumes and doses were noted. The patients were evaluated in terms of acute dysphagia (AD) and radiation therapy (RT)-associated xerostomia. Results The median volume of the TGs was 3.5(2.1-5.9)cc. No increased standardized uptake values (SUV) were observed in the TGs. There was no significant relationship between TGs values and the third or sixth months of xerostomia after RT. There was a significant relationship between grade ≥2 AD and TGs-Dmean (p0.020); TGs-V25(%) (p0.007); TGs-V30(%) (p0.009); TGs-V40% (p0.011); TGs-V50% (p0.010), TGs-V60% (p0.045). In terms of the risk of grade ≥2 AD, the cut-off value of the TGs-Dmean was analyzed for 50 Gy, with 75% sensitivity and 73.3% specificity (p 0.020; AUC 0.746; 95% CI 0.561-0.929). Additionally for grade ≥2 AD, the cut-off value of the TGs-V25(%) was analyzed 78 with 81.3% sensitivity and 80.0% specificity (p 0.011; AUC 0.769; 95% CI 0.591-0.947). Conclusion A significant correlation was found between TGs doses and AD during RT. TGs-V25(%) value showed higher significance. In future studies, the clinical significance of TGs can be studied especially on this value. The relationship between TGs doses and xerostomia should be evaluated with a larger series.

Tubarial salivary glands on PSMA ligands based PET imaging and post 177Lu PSMA therapy scan: reiterating its importance

68Ga-PSMA PET/CT has been routinely utilized in patients with intermediate to high-risk category prostate carcinoma for staging, biochemical recurrence and before planning the PSMA radioligand therapy (RLT). 177Lu-PSMA RLT has also been approved by FDA as a novel treatment modality in metastatic carcinoma prostate patients who have failed to other lines of treatment. The non-target organs like salivary and lacrimal glands have shown to have high physiological PSMA uptake on PSMA PET/CT. Recently, strong uptake of PSMA ligand has also been noted in the dorsal wall of the nasopharynx in the region of torus tubarius on PSMA PET/CT, which has led to the identification of new pair of salivary gland structures called "tubarial salivary glands". The clinical significance of these distinct anatomical structures lies in the fact these structures might be involved in a variety of immune related, inflammatory disorders, malignancies and could be a probable organ at risk during radiotherapy in case of head and neck malignancies, causing adverse effects to the patient.

Initial evaluation and external validation of 68Ga-PSMA-11 PET/CT in tubarial gland characterization

INTRODUCTION

Radiotracer 68Ga-PSMA-11 used in PET/CT scans allows for identification and localization of gland tissue. It allows for their consideration in clinical scenarios and to design further and stronger research to answer pertinent questions regarding their function and implications. We aimed to externally validate first reported findings of location, size, and ligand uptake of the tubarial glands using 68Ga-PSMA-11 PET/CT.

MATERIALS AND METHODS

A cross-sectional study was performed with 68Ga-PSMA-11 PET/CT studies of patients with prostate cancer confirmed diagnosis from the database of the Radiology Department from 2018 to 2022. The maximum cephalocaudal length (CCL) in the tubarial glands and the Maximum Standardized Uptake Value (SUVmax) of major glands were recorded.

RESULTS

A total of 202 patients were included (mean age 67.43 ± 8.5). The mean CCL of the tubarial glands was 37.38 ± 9.84 and a SUVmax of 6.56 ± 2.14. The rest of the glands were as follows: parotid 15.12 ± 4.43, submandibular 16.82 ± 5.43 and sublingual 5.84 ± 3.24. No differences were found between laterality. A weak correlation between age and SUVmax of tubarial glands was identified. Tubarial glands had a similar 68Ga-PSMA-11 uptake to that of sublingual glands.

CONCLUSION

This study corroborates the existence of a conglomerate of glands in the nasopharynx roof, near the posterolateral pharyngeal recess. It serves as validation in a different population with similar results in previous research. Without 68GA-PSMA-11 PET/CT the abundance, configuration and potential clinical relevance of these glands would probably not have been identified. Radiotracer uptake was similar amongst the major salivary glands, with a more similar uptake to that shown by the sublingual gland.

Atlas of non-pathological solitary or asymmetrical skeletal muscle uptake in [18F]FDG-PET

Positron emission tomography (PET) using 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) is widely used in oncology and other fields. In [¹⁸F]FDG PET images, increased muscle uptake is observed owing exercise load or muscle tension, in addition to malignant tumors and inflammation. Moreover, we occasionally observe non-pathological solitary or unilateral skeletal muscle uptake, which is difficult to explain the strict reason. In most cases, we can interpret them as not having pathological significance. However, it is important to recognize such muscle uptake patterns to avoid misdiagnoses with pathological ones. Therefore, the teaching point of this pictorial essay is to comprehend the patterns of solitary or asymmetrical skeletal muscle uptake seen in routine [¹⁸F]FDG-PET scans. As an educational goal, you will be able to mention muscles where intense physiological [¹⁸F]FDG uptake can be observed, differentiate between physiological muscle uptake and lesion, and discuss with any physicians or specialists about uncertain muscle uptake.

Abnormal [18F]fluorodeoxyglucose accumulation to tori tubarius in IgG4-related disease

OBJECTIVES

Tubarial glands (TGs) are recently refocused gland tissues localized near the tori tubarius in the nasopharynx and their clinical relevance is not clear yet. IgG4-related disease (IgG4-RD) is a progressive fibrosing condition and salivary glands are well-affected lesions. The aim of the present study is to examine [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) accumulation to the tori tubarius in IgG4-related disease (IgG4-RD).

METHODS

48 patients with IgG4-RD who underwent positron emission tomography (PET) scanning with [¹⁸F]FDG were included and semi-quantitative analysis of [¹⁸F]FDG accumulation to tori tubarius was performed along with the clinical features and histopathological analysis.

RESULTS

Of the 48 patients, abnormal [¹⁸F]FDG accumulation (metabolic tumour volume ≥ 1) to tori tubarius was observed in 15 (31.3%), all of whom had lesions in other head and neck glands. IgG4-RD patients with abnormal [¹⁸F]FDG accumulation to tori tubarius showed swollen nasopharyngeal walls around tori tubarius and forceps biopsy of the lesion revealed acinar cells and IgG4-positive plasma cells histologically. Abnormal [¹⁸F]FDG accumulation (maximum standard uptake value, metabolic tumour volume and total lesion glycolysis) to tori tubarius correlated with higher IgG4 and lower IgA serum concentrations.

CONCLUSIONS

Abnormal [¹⁸F]FDG accumulation to tori tubarius can be observed in patients with IgG4-RD and the abnormal [¹⁸F]FDG accumulation to tori tubarius can be a clue of TG involvement in IgG4-RD.