The Application Study Of Cerebral MR Perfusion Imaging On Radiation-induced Injury Following Radiotherapy For Nasopharyngeal Carcinoma

Objective:1.To evaluate the methodology and quality cotrol of cerebral MR PWI on patients with NPC following radiotherapy.2. To study the appearance and diagnostic value of MR PWI on on radiation-induced injury following radiotherapy for NPC.3. Evaluate the comparative imaging among MR PWI, CT, MRI and PET in patients with radiation injury following radiotherapy for NPC.Materials and Methods:I.MR PWI were obtained in 28 patients following radiotherapy for NPC. Fifteen patients without radiation injury in the temple lobes, and 13 with radiation injury which were diagnosed by clinical appearances and MRI, but they had non-lesions in the tempral lobes(i.e, the contralateral). A 1. 5 T superconductive MR scanner was used. The 15 slices which were over the line between the external auditory canal and supraorbit for 40 times dynamic MR scan during a bolus intravenous administration of Gd-DTPA. The contrast agent was Gadopentetic acid meglumine injection(0.5 mol/L), injection rate 5 ml/s, total dose 0.1 ramol/kg body weight, injected by mechanical injector. The scan parameters: continuous data acquisition was performed starting at the the injection. A total of 600 images were obtained. The data were evaluated at thework desk with a MR perfusion software. When ROIs were chosen, the signal-time curves appeared. Then maximum signal drop(MSD), maximum signal reduced rate(SRRmax), mean transit time(MTT) and time to peak (TIP) were all easily calculated. Statistical analysis was performed using SPSS windows 10. 0 version software package. Stardard descriptive statistical mean + SD were obtaind.2. MR PWI were obtained in 21 patients with radiation injury in temporal lobes following radiotherapy for NPC, which were diagnosed by clinical appearances and MRI. Fifty-six ROIs were chosen at the lesion sites. Stardard descriptive statistical mean ±SD of MSD, SRRmax, TIP and MTT were obtaind. Two-tailed t tests were used to compare above non-lesions' and lesions' distributed data respectively. Statistical significant difference was declared at a level of 0. 05.3. The clinical information, imaging records and pathological data in 91 patients with brain radiation injury following radiotherapy for nasopharyngeal carcinoma examined over a 10-year period. Sixty-three patients performed CT (81 examinations), 63 cases carried out MR imaging (76 examinations). Thirty-five patients underwnt both CT and MR imaging. Twenty-one patients were carried out on MR PWI. Seven patients underwnt PET.Results:1.Eighty-three ROIs among 28 patients were chosen in the non-lesion white matters of the radiated temporal lobes. The calculated parameters from the STC were the following: MSD=120. 71 ±49. 15; SRRmax=(16. 22± 6. 16)%; MTT=(16. 68±2. 87)s;TTP==(15. 96 ±2.70)s.2. Among the 21 patients who suffered from radiation injury of the temporal lobes. Twenty-six areas in 19 patients of reduced MSD maps and 4 areas of 2 cases of no cerebral blood flow were showed. Fifty-six ROIs' calculated parameters were: MSD=83. 57±39. 59;SRRmax= (8.12±3. 69) % ; MTT= (16. 68±2. 87) s; TTP= (15. 96 ± 2. 70) s. Decreased MSD, SRRmax and prolonged MTT and TIP were detected with the aid of SPSS statistics software and P<0. 05 in all groups compared with the non-lesions' . There were very significant differences between two groups for the all 4 sorts of parameters. 3. Among nighty-one radiated injury patients, the radiation injury lesions occurred in the temporal lobes, brain stems or cerebellum. Their CT appears were homogeneous or heterogeneous density. The CT appears were homogeneous or heterogeneous density. If the lesions were situated in temporal lobes, they presented as "finger-like" hypo-density. Twenty-three patients (29 lesions) undenwent contrast-enhanced CT scan, 86.2% (25/29) of the lesions showed no enhancement. MRI demonstrated prolonged T1 and T2 relaxation time in the injured tissue, presenting as homogeneous or heterogeneous signal intensity. MR PWI were carried out on 21 patients, 60 lesions in the temporal l...