Role of 3D Pseudocontinuous Arterial Spin-Labeling Perfusion in the Diagnosis and Follow-Up in Patients with Herpes Simplex Encephalitis

BACKGROUND AND PURPOSE: Early diagnosis and treatment of herpes simplex encephalitis are crucial to reduce morbidity and mortality. Our aim was to investigate the role of 3D pseudocontinuous arterial spin-labeling in herpes simplex encephalitis. MATERIALS AND METHODS: From 2014 to 2019, seventeen consecutive patients with herpes simplex encephalitis and 15 healthy volunteers were recruited in the study. Conventional MR imaging and 3D pseudocontinuous arterial spin-labeling were performed in all subjects. According to the disease duration, the lesions were classified into 3 groups, including acute, subacute, and chronic stages, respectively. Clinical, neuroradiologic, and follow-up features were studied. The normalized lesion/normal tissue CBF values of lesions at different stages were measured and compared with those in the control group, respectively. RESULTS: Compared with the control group, herpes simplex encephalitis demonstrated hyperperfusion in 11 acute cases and 6 subacute cases and hypoperfusion in 6 chronic cases. The mean normalized lesion/normal tissue CBF values of the lesions were 2.68 ? 0.54 in the acute stage, 2.42 ? 0.52 in the subacute stage, and 0.87 ? 0.30 in the chronic stage, respectively. The mean normalized lesion/normal tissue CBF values of acute and subacute lesions were significantly higher than those of the control group (1.33 ? 0.08; P < .001, respectively), while the mean normalized lesion/normal tissue CBF values of chronic lesions were lower than those of the control group (P < .05). Gradual perfusion reduction on serial 3D pseudocontinuous arterial spin-labeling was observed in herpes simplex encephalitis after effective therapy. CONCLUSIONS: Conventional MR imaging remains most helpful in the diagnosis of herpes simplex encephalitis, while 3D pseudocontinuous arterial spin-labeling could be an adjunctive technique by providing dynamic CBF features at different stages in herpes simplex encephalitis.