Diffusion-weighted magnetic resonance imaging to evaluate major salivary gland function before and after radiotherapy

Dirix, Piet; De Keyzer, Frederik; Vandecaveye, Vincent; Stroobants, Sigrid; Hermans, Robert; Nuyts, Sandra

doi:10.1016/J.IJROBP.2007.12.011

Title

Diffusion-weighted magnetic resonance imaging to evaluate major salivary gland function before and after radiotherapy

Author

Dirix, Piet

De Keyzer, Frederik

Vandecaveye, Vincent

Stroobants, Sigrid

Hermans, Robert

Nuyts, Sandra

Abstract

Purpose To evaluate diffusion-weighted (DW)-MRI as a noninvasive tool to investigate major salivary gland function before and after radiotherapy (RT) for head and neck cancer (HNC). Methods and Materials DW-MRI was performed in 8 HNC patients before and after parotid-sparing RT (mean dose to the contralateral parotid gland <26 Gy). A DW sequence was performed once at rest and then repeated continuously during salivary stimulation. Apparent diffusion coefficient (ADC) maps for both parotid and submandibular glands were calculated. Findings were compared with salivary gland scintigraphy. Results Before RT, the mean ADC value at rest was significantly lower in the parotid than in the submandibular glands. During the first 5 min of stimulation, the ADC value of the salivary glands showed a decrease, followed by a steady increase until a peak ADC, significantly higher than the baseline value, was reached after a median of 17 min. The baseline ADC value at rest was significantly higher after RT than before RT in the nonspared salivary glands but not in the spared parotid glands. In the contralateral parotid glands, the same response was seen as before RT. This pattern was completely lost in the nonspared glands. These results corresponded with remaining or loss of salivary function, respectively, as confirmed by salivary gland scintigraphy. Conclusions Diffusion-weighted-MRI allows noninvasive evaluation of functional changes in the major salivary glands after RT and is a promising tool for investigating radiation-induced xerostomia.

Language

English

Source (journal)

International journal of radiation oncology, biology, physics. - Bedford

Publication

Bedford : 2008

ISSN

0360-3016

DOI

10.1016/J.IJROBP.2007.12.011

Volume/pages

71 :5 (2008) , p. 1365-1371