Magnetic Resonance Imaging Findings of Temporal Lobe Radiation Encephalopathy in Nasopharyngeal Carcinoma

Objective： To observe the magnetic resonance imaging （MRI） morphological features of radiation encephalopathy （REP） in nasopharyngeal carcinoma （NPC） and investigate their diagnostic value. Methods： The MRI data of 160 lesions from 104 NPC patients with the diagnosis of temporal lobe REP were retrospectively analyzed. The MRI was performed after radiation therapy of NPC with an interval ranged from 8 months to 13 years. The imaging sequences included T1-weighted imaging and T2-weighted imaging. Additionally T1-weighted imaging with injection of the contrast agent of Gd-DTPA was performed in 111 lesions and fluid attenuated inversion recovery （FLAIR） was performed on 37 lesions, and among them, 2 cases were subjected to MR perfusion weighted imaging （PWI）. Results： Unilateral temporal lobe was involved in 48 cases of REP, bilateral temporal lobe in 56 cases of REP respectively, with a total of 160 lesions. The REP in the white matter displayed hyper-intensity signal on T2-weighted imaging which could be homogenous, whereas areas with heterogeneous hypo-intensity signal could be seen in 59 of them otherwise with hyper-intensity signal, and 91 lesions of white matter were associated with gray matter lesions with an appearance of hypo-intensity signal on T1-weighted imaging and hyper-intensity signal on T2-weighted imaging. In 111 lesions with the Gd-DTPA enhanced T1-weigthed imaging, 91 showed the enhancement of brain parenchyma. Hemorrhage and hemosiderosis occurred in 5 lesions of REP. Conclusion： REP in NPC has a multiplicity of the imaging features on MRI, in addition to the common involvement of white matter, including other relatively frequent findings, such as the involvement of gray matter, hemorrhage, hemosiderosis and blood-brain barrier destruction, those could be clearly revealed on MRI.

Clinical characteristics and changes in living quality of patients with radiation encephalopathy induced by radiation therapy for treating nasopharyngeal carcinoma

BACKGROUND： Radiation encephalopathy （RE） caused by radiation therapy of nasopharyngeal carcinoma severely influences patients＇ quality of life （QOL）. The factors, which influence such patients＇ QOL, have not been confirmed. OBJECTIVE： To observe the clinical and imageological characteristics of patients with radiation therapy of nasopharyngeal carcinoma-induced RE and the changes in QOL, and analyze QOL influencing factors. DESIGN： Retrospective case analysis. SETTING： Department of Neurology, the Second Affiliated Hospital of Sun Yat-sen University. PARTICIPANTS： Eighty-nine inpatients or outpatients with RE induced by radiation therapy of nasopharyngeal carcinoma admitted to Sun Yat-sen University Cancer Center and Department of Neurology, the Second Affiliated Hospital of Sun Yat-sen University from March 1994 to August 2004 were involved in this experiment. They all met the diagnosis criteria of RE from MERRITT＇S neurology （10th edition）. Thirty-three involved patients were randomly chosen as RE group. Another 34 concurrent inpatients or outpatients with nasopharyngeal carcinoma who received radiation therapy but without RE were chosen as control group. Informed consents of detected items were obtained from all the involved subjects. METHODS： （1） Patients were evaluated when they were followed up. The World Health Organization Quality of Life Questionnaire abbreviated version （WHOQOL-BREF） was used for on-the-spot evaluation. High points of WHOQOL-BREF indicated better QOL. The Late Effects on Normal Tissues - Subjective, Objective, Management and Analytic （LENT-SOMA） scale for evaluating radiation injury was used to evaluate headache and neurologic disorder of patients with RE induced by radiation therapy of nasopharyngeal carcinoma. The evaluation was graded into 5 degrees. High degrees indicted severer clinical symptoms. （2） Disease latency （i.e. time interval from symptoms and body signs appearing or radiation therapy ending to onset）, initial symptoms, common symptoms, imageological characteristics, QOL and other related factors of patients were recorded. （3） Statistical management was carried out with SPSS 10.0 software. MAIN OUTCOME MEASURES： QOL and clinical characteristics of patients with RE induced by radiation therapy of nasopharyngeal carcinoma as well as QOL influencing factors. RESULTS： All the involved subjects participated in the final analysis. （1） Disease latency of patients with RE ranged from 0 to 24 years, and 95% confidence interval was 0 to 15 years. There were significant differences in amount of invaded cases between 6 months after one radiation therapy and 6 months after two or more radiation therapies （ x^2=36.76, P 〈 0.01）. （2） The common initial symptom of patients with RE was glossopharyngeal paralysis （33 cases, 37%）. （3） The first 3 common symptoms of patients with RE were glossopharyngeal paralysis （52 cases, 58%）, limb inertia and sensory disorder （25 cases, 28%） and headache （25 cases, 28%）.（4）Imageology of patients with RE was characterized by long TI and T2 signal shadow on magnetic resonance. （5）Total scores of health, of daily life and of social relationship, measured with WHOQOL-BREF, of patients in RE group were significantly lower than those in the control group, respectively [ （2.06 ± 0.86） points vs. （2.59 ± 0.66） points; （2.45 ± 0.75 ） points vs. （2.91 ± 0.75 ） points; （51.67±15.24） points vs. （59.22±13.03） points, P 〈 0.05]. Patients undergoing two or more radiation therapies were inferior to those undergoing one radiation therapy in total scores of health, and of daily life, scores of physiology, and of psychology （P 〈 0.05）. （6）Glossopharyngeal paralysis was negatively correlated with scores of psychology, total scores of daily life and of health in WHOQOL-BREF （P 〈 0.05）; Head was negatively correlated with scores of psychology in WHOQOL-BREF （P 〈 0.05）; Neurologic deficit was negatively correlated with scores of psychology, and total scores of health in WHOQOL-BREF （P 〈 0.05）. CONCLUSION： （1）The latency of RE of patients undergoing two or more radiation therapies is remarkably shortened, and QOL is decreased, but there is no difference in QOL between two genders. （2） Brain edema is common in imageology of RE after radiation therapy. The first 3 ones of initial symptoms and common symptoms both are glossopharyngeal paralysis, neurologic deficit and headache, which greatly negatively influence QOL of patients.

PET/CT imaging of delayed radiation encephalopathy following radiotherapy for nasopharyngeal carcinoma

Background With the significant improvement in the survival of patients with nasopharyngeal carcinoma （NPC） undergoing radiotherapy and the growing availability of the sophisticated imaging modalities, the number of radiation encephalopathy （RE） cases relating to NPC radiotherapy is increasing. In this study, we investigated the metabolic and density changes of the compromised brain tissues during delayed RE using a positron-emission tomography-computed tomography （PET/CT） to provide clinical evidences for the diagnosis of delayed RE following radiotherapy for NPC. Methods The PET/CT manifestations and the clinical data of 53 pathologically confirmed NPC patients with delayed RE following radical radiotherapy and 15 healthy volunteers were investigated. The standardized uptake values （SUV） of the bilateral temporal lobes, the occipital lobe and the brain stem were measured respectively; and then the metabolic reduction rate of 88 temporal lobes and 13 brain stems were calculated for a statistical comparison between the two groups. Results The earliest case of delayed RE in the investigated patients occurred 1.5 years after radiotherapy. Delayed RE frequently involved the inferior temporal lobe. For patients with delayed RE confirmed by clinical symptoms and imaging findings, PET maintained a 100% coincidence rate with CT; however, in the 25 temporal lobes of the 35 delayed RE patients, PET revealed obvious hypometabolic changes whereas CT displayed normal density. The incidence of brain stem metabolic reductions was 24.5% （13/53） in the investigated patients, including 4 patients with hypometabolic changes shown by PET and negative finding shown by CT. The incidence of granuloma adjacent to the hypometabolic region in the temporal lobe was 12.5% （11/88）. Conclusion Delayed RE patients exhibit significant hypometabolic changes in the inferior temporal lobe, captured by PET much earlier than by CT. PET/CT offers a valuable means for the diagnosis of delayed RE in subacute stages and granuloma formation.