CT Perfusion in Predicting Treatment Response of
Nasopharyngeal Carcinoma
Lojana Tuntiyatorn MD*, Ekkapong Fusuwankaya MD*,
Thiti Sawangsilpa MD**, Thongchai Bhongmakapat MD***
Affiliation :
* Division of Neuroradiology, Department of Radiology, Faculty of Medicine, Ramathibodi Hospital,
Mahidol University, Bangkok, Thailand
** Division of Radiation Oncology, Department of Radiology, Faculty of Medicine, Ramathibodi Hospital,
Mahidol University, Bangkok, Thailand
*** Department of Otolaryngology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Background : Direct nasopharyngoscope with biopsy is the gold standard for assessing tumor response of nasopharyngeal
carcinoma (NPC). It is invasive with risk of hemorrhage or infection.
Objective : Explore the usefulness of pre-treatment CT perfusion (CTP) and clarify the parameters in predicting the treatment
response.
Material and Method: Twelve patients with histologically proven NPC who underwent pretreatment contrast enhanced CT
(CECT) and CTP with parameters (blood flow (BF), blood volume (BV) and permeability), followed by CECT at three
months after complete concurrent chemo-radiotherapy or radiotherapy were included in this prospective, cross-sectional
study. Pre- and post-treatment primary tumor volumes based on free hand drawn region encompassing the entire primary
tumor were measured and compared. The response to therapy was also assessed by RECIST guideline version 1.1, based
on sum of the diameters of longest diameter for primary tumor and minimal transverse diameter for nodal lesions for all
target lesions on the pre- and post-treatment imaging, and classified into “Non-response” group and “Complete response”
group. Statistical analysis was performed using Pearson’s correlation coefficients and Mann-Whitney U test.
Results : Ten and two patients (83.3%, 16.7%) belonged to “Complete response” and “Non-response” groups respectively.
Elevated permeability, BF and BV had a following trend of positive correlation with degree of primary tumor volume
reduction without statistical significance. The values of permeability, BF, and BV had a trend to be higher in “Complete
response” group compared with “Non-response” group (p = 0.053, 0.390 and 0.519 respectively). The permeability had
the highest predictive value with an area under the ROC curve of 0.95 and cutoff value of 45 ml/100 g/min (sensitivity,
100%; specificity, 90%).
Conclusion : Pre-treatment CTP can be useful non-invasive tool in predicting treatment response of NPC. Permeability is
the excellent parameter used to differentiate between complete and non-response groups.
Keywords : CT perfusion, Prognosis, Outcome, Response, Permeability, Blood flow, Blood volume, Nasopharyngeal carcinoma
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