[Diagnostic imaging of the salivary glands in patients undergoing radiotherapy of head and neck neoplasms].

INTRODUCTION

Radiotherapy of head and neck cancers changes the shape and function of the salivary glands included in the treated region. We investigated the morphological and functional alterations in the major salivary glands in 15 patients treated with radiotherapy for head and neck cancers (total dose: 55-66 Gy).

MATERIAL AND METHODS

All the patients underwent B-mode and power Doppler US, CT and 99mTC salivary scintigraphy, before, at the end, and 60-80 days after radiotherapy.

RESULTS

At the end of treatment, US showed irregular margins and inhomogeneous parenchymal echogenicity in 13 parotid and in eight submandibular glands. Doppler US showed of focal hyperemia and focally decreased or no intraparenchymal flow in nine parotid and in two submandibular glands. CT demonstrated parenchymal inhomogeneity with increased and decreased density areas, cancers irregular margins, and gland atrophy in 15 parotid and in eight submandibular glands. Salivary scintigraphy depicted injuries of the major salivary glands detecting their reduced pertechnetate uptake in 12 parotid and in eight submandibular glands, with a decreased drug excretion in 12 parotid and in 12 submandibular glands.

DISCUSSION AND CONCLUSION

Our findings confirm that the major salivary glands are affected by radiotherapy, which makes their morphological and structural monitoring of vital importance. US is the technique of choice for its low cost and easy execution, and it is well accepted by the patients because it requires no exposure to ionizing radiations. Power Doppler provided no relevant information, but it confirmed the high resistance of small and middle caliber vessels after radiotherapy. Scintigraphy clearly showed the glands involvement demonstrating decreased uptake technetium secretion and excretion. In conclusion, US and CT are both extremely useful in the study of the morphological changes of the major salivary glands.