3D MR sialography as a tool to investigate radiation-induced xerostomia: feasibility study.
OBJECTIVE
To evaluate whether magnetic-resonance (MR) sialography can be used to investigate radiation-induced xerostomia. Preradiotherapy (pre-RT) and postradiotherapy (post-RT) MR sialographic images of the major salivary ducts (parotid and submandibular) were compared.


METHODS
Magnetic-resonance sialography was performed pre-RT, and 6 weeks and 6 months post-RT on 9 patients with T1-4N0-2M0 naso- or oropharyngeal tumors, on a 1.5-T MR scanner. Patients were positioned in the scanner, using a radiotherapy immobilization mask. Image registration of the MR sialograms pre- and post-RT with each other and with the CT and consequently the dose distribution was performed. A categorical scoring system was used to compare the visibility of ducts pre-RT and post-RT.


RESULTS
Good-quality MR sialographic images were obtained, and image registration was successful in all cases. The visibility score of the parotid ducts and submandibular ducts was reduced at 6 weeks post-RT, which means that the full trajectory of the salivary ducts, from the intraglandular space to the mouth cavity, was only partially visualized. For some of the parotid ducts, the visibility score improved at 6 months post-RT, but not for the submandibular ducts. The mean dose for the parotid glands was 35 Gy (1 standard deviation [SD] 3 Gy), and for the submandibular glands it was 62 Gy (SD, 8 Gy).


CONCLUSIONS
Three-dimensional MR sialography is a promising approach for investigating xerostomia, because radiation-induced changes to the saliva content of the ducts can be visualized.
Astreinidou
Eleftheria
E
Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands. E.Astreinidou@umcutrecht.nl
Roesink
Judith M
JM
Raaijmakers
Cornelis P J
CP
Bartels
Lambertus W
LW
Witkamp
Theo D
TD
Lagendijk
Jan J W
JJ
Terhaard
Chris H J
CH
D005240:Feasibility Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D009959:Oropharyngeal Neoplasms / Q000532:radiotherapy*; D010306:Parotid Gland / Q000033:anatomy & histology; D011446:Prospective Studies; D011832:Radiation Injuries / Q000175:diagnosis*; D011879:Radiotherapy Dosage; D018987:Salivary Ducts / Q000033:anatomy & histology; D012472:Salivation; D013363:Submandibular Gland / Q000033:anatomy & histology; D014987:Xerostomia / Q000175:diagnosis* / Q000209:etiology