Impact of nasopharyngeal irradiation and gadolinium administration on changes in T 1 signal intensity of the dentate nucleus in nasopharyngeal malignancy patients without intracranial abnormalities

BACKGROUND: Irradiation has been found to increase T1 signal intensity (SI) of the dentate nucleus (DN) by accelerating the gadolinium deposition in patients after multiple gadolinium-based contrast agent (GBCA) administrations. Several reports have focused on this phenomenon in patients with brain tumors; however, data in patients receiving irradiation with no intracranial abnormalities (NIAs) are lacking. PURPOSE: To explore how nasopharyngeal irradiation affected SI changes on unenhanced T1 -weighted imaging (T1 WI) in the DN in nasopharyngeal malignancy (NPM) patients who presented with NIAs and who had multiple injection doses (IDs) of linear GBCAs. STUDY TYPE: Single-center, retrospective, case-control study. POPULATION: In all, 132 subjects: 66 NPM patients, 66 matched controls. FIELD STRENGTH/SEQUENCE: 1.5T and 3T/T1 WI, T2 WI, and fluid-attenuated inversion recovery (FLAIR). ASSESSMENT: Radiation doses (RDs) were calculated by a radiotherapy technician. SIs were measured by a radiologist. The DN-to-cerebellar white matter (CWM) SI ratios and their relative percentage change (Rchange ) were compared. STATISTICAL TESTS: Shapiro-Wilk test, paired t-test, independent t-test, Mann-Whitney U-test, Pearson and Spearman correlation. RESULTS: DN/CWM b ratios or R change from the NPM group were significantly higher than those from the control group (P 0.05). Positive correlations between R change , DN/CWM b ratio, and the number of IDs were found in both the NPM and control groups (P /=10) than for the lower-IDs subgroup ( /=10. However, no significant association between R change and RDs to the DNs was found. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:250-259.