Sheng‑Chieh Chana, Shu‑Hang Ngb*, Chih‑Hua Yehb, Kai‑Ping Changc
aDepartment of Nuclear Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan, bDepartment of Diagnostic Radiology, Linkou Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan, cDepartment of Otorhinolaryngology, Linkou Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
Open Access funded by Buddhist Compassion Relief Tzu Chi Foundation
Abstract
Objectives: The clinical significance of positron emission tomography/magnetic resonance imaging (PET/MRI) functional parameters in nasopharyngeal carcinoma (NPC) remains unclear. The purpose of this prospective study was two‑fold: (1) to investigate the associations between simultaneously acquired PET/MRI perfusion, diffusion, and glucose metabolism parameters in patients with NPC and (2) to analyze their predictive value with respect to treatment failure. Materials and Methods: We enrolled 85 patients with primary NPC who simultaneously underwent 18F‑fluorodeoxyglucose PET/CT and PET/MRI before definitive treatment. The following variables were determined: (1) functional parameters from the MRI component, including perfusion values (Ktrans, kep, ve, and initial area under the enhancement curve) and apparent diffusion coefficient (ADC) values, and (2) PET parameters, including metabolic tumor volume (MTV). The reciprocal interrelationships between these parameters and their correlations with treatment failure were examined. Results: We observed significant negative associations between Ktrans and ADC (r = −0.215, P = 0.049) as well as between ve and ADC (r = −0.22, P = 0.04). Correlations between PET and MRI functional parameters were not statistically significant. Treatment failures were observed in 21.2% of patients without distant metastases. Multivariate analysis identified ve as a significant independent predictor for treatment failure (P = 0.022), whereas MTV showed a borderline significance (P = 0.095). Patients in whom both ve and MTV values were increased had a significantly higher rate of treatment failure (62.5%) than those with either one (21.9%) or no (7.7%) increased parameter (P = 0.004). Conclusion: Correlation analyses revealed complex interrelationships among PET and MRI indices measured in patients with NPC. These parameters may have a complementary role in predicting treatment failure in this clinical setting.
Keywords: DCE-MRI, Diffusion-weighted MRI, Nasopharyngeal carcinoma, Positron emission tomography/magnetic resonance imaging, Prognosis
