Amide proton transfer MRI detects early changes in nasopharyngeal carcinoma: providing a potential imaging marker for
Sahrish Qamar1, Ann D King2, Qi-Yong Ai1
1Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, 30-32 Ngan Shing Street, Shatin, New Territories, Hong Kong S.A.R., China.
Purpose:
To determine if treatment of nasopharyngeal carcinoma (NPC) induces early changes in amide proton transfer-weighted (APTw) magnetic resonance imaging (MRI), and to perform a preliminary evaluation of APTw imaging in response assessment.
Methods:
Sixteen patients with NPC planned for treatment with radiotherapy and/or chemotherapy underwent APTw imaging of the primary tumour pre-treatment and 2-week intra-treatment. Difference in pre- and intra-treatment APT mean (APTmean) was compared using the Wilcoxon signed rank test. Differences in APTmean and percentage change (%Δ) in APTmean were compared between responders and non-responders based on the outcome at 6 months, using the Mann-Whitney U test.
Results:
APTmean decreased in 9/16 (56.3%) and increased in 7/16 (43.7%) with no significant difference between the pre- and intra-treatment APT values for the whole group (p > 0.05). NPC showed response in 11/16 (68.8%) and non-response in 5/11 (31.2%). There were significant differences between the %Δ of responders and non-responders for APTmean (p = 0.01). Responders showed %Δ decrease in APTmean of - 23.12% while non-responders showed a %Δ increase in APTmean of + 102.28%.
Conclusion:
APT value changes can be detected in early intra-treatment. Intra-treatment %Δ APTmean shows potential in predicting short-term outcome.
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