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Background: Growing glioblastoma is associated with an impairment of the blood brain barrier and increased hemodynamic parameters (CBV, CBF), which is related to advanced tumor angiogenesis. Arterial spin labeling (ASL) perfusion, an additional study to the routine intravenous contrast-enhanced magnetic resonance imaging (MRI), may be a technique for assessment of hemodynamics and identification of the residual tumor tissue.Aim: To study the potential of native ASL to assess hemodynamic parameters and detect residual tumor tissue in the patients who had undergone surgical resection of glioblastoma.Materials and methods: At 2 to 4 weeks after surgery for glioblastoma grade IV, brain MRI with native ASL perfusion and subsequent intravenous contrast enhancement was performed in 63 patients. Cerebral blood flow (CBF) values were measured in three areas of interest: in the presumptive tumor tissue (PTT) with maximal perfusion, in the postoperative scar tissue (PST) and in the deep white matter (DWM) of the contralateral hemisphere.Results: According to their CBF values, all patients were categorized into two groups. Group 1 included 43 patients (68.3%) with mean CBF in PTT of 135.4±41.3 ml/100 Gr/min (min 73.9, max 255.9). These values were 5 to 6-fold higher than the CBF values in the PST and 6 to 8-fold higher than those in DWM. Group 2 included 20 patients (31.7%) without any areas of abnormal CBF increase in PST, with its mean value of 22.1±5.6 ml/100 Gr/min (min 13.9, max 37.1), which was close to the CBF level in DWM (19.8±4.6 ml/100 Gr/min, p=0.06). There were no between-group differences for the CBF values in PST (p=0.6), and DWM (p=0.7).Conclusion: ASL MR perfusion technique has good potential for the identification of residual tumor tissue after surgical resection of glioblastoma and can be an alternative to contrast enhancement during long-term follow up.

Multiple system atrophy (MSA) is a progressive neurodegenerative disease. However, little is known about the regional cerebral blood flow (rCBF) and functional connectivity changes in the disease. In this study, the magnetic resonance imaging (MRI) data including 24MSA-c-type patients and 20 healthy controls were collected by using voxel wise arterial spin labeling (ASL) perfusion analysis, several regions of the altered rCBF were identified in the MSA c-type patients. And then, the changes of the functional connectivities of identified rCBF regions were analyzed by using functional MRI (fMRI). Finally, rCBF value of cerebellum was extracted to differentiate the MSA c-type patients and controls. Compared with the controls, the MSA c-type patients showed distinct disruption of rCBF in the cerebellum. The disconnection of the identified cerebellar regions was revealed in several regions in the MSAc-type patients, including right middle frontal gyrus (MFG), right precuneus, left superior temporal gyrus (STG), right lingual gyrus, left postcentral gyrus (PoCG), right cerebellum 7b, right cerebellum 8, and left cerebellum 4,5. These regions were involved in the default mode network (DMN), sensorimotor network, visual associated cortices, and cerebellum. Using the rCBF value of vermis as biomarker, the two groups can be differentiated and reached a sensitivity of 95.8% and specificity of 100%. This is the first study to demonstrate the MSA-specific rCBF abnormalities using the ASL method, which are closely associated with several functional networks on resting state fMRI. The rCBF of vermis might be used as the potential imaging biomarker for the early diagnosis of MSA c-type.