ABSTRACT
Objective To observe the findings of 1H magnetic resonance spectroscopy ( 1H MRS) and explore its value for diagnosis of radiation induced-temporal lobe necrosis in nasopharyngeal carcinoma (NPC). Methods Thirteen patients with definite clinical diagnosis of radiation induced temporal lobe necrosis in NPC underwent 1H MRS. All 1H MRS examinations were performed on a Singa Horizont 1.5 T whole body MR system with point resolved spectroscopy (PRESS) and chemical-shift selective saturation (CHESS) (TR=2000?ms,TE=144 ?ms). The voxel (2?cm ? 2?cm ? 2?cm) was positioned in both of the lesion and the contralateral side of the temporal lobe as the control (except for bilateral lesions). 2THZ]Results The interval between radiation and the examination ranged from 32 to 172 months ( median, 42 months). Eighteen lesions were observed in 13 patients (5 patients with bilateral lesions). 1H MRS was performed on 17 lesions and 8 control temporal lobes. The mean values of NAA/ Cr in the lesions and the control temporal lobes were 1.33?0.28、1.78?0.34 respectively(t=3.22, P=0.005). Three lesions showed NAA、Cho and Cr peak absent (2 lesions with Lip peak ). Among 8 patients with the control temporal lobes 1H MRS examined, Cho/Cr decreased in 6 patients (75%). Four lesions showed Lip , Lac and MI, respectively. Conclusions The radiation-induced temporal lobe necrosis shows abnormal features on 1H MRS. Significant decrease of NAA/ Cr as well as Cho/Cr are observed in most patients. 1H MRS may play a role in the diagnosis of radiation induced temporal lobe necrosis.