Comparative analysis of the diffusion kurtosis imaging and diffusion tensor imaging in grading gliomas, predicting tumour cell proliferation and IDH-1 gene mutation status.

INTRODUCTION: Few studies have applied diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) for the comprehensive assessment of gliomas [tumour grade, isocitrate dehydrogenase-1 (IDH-1) mutation status and tumour proliferation rate (Ki-67)]. This study describes the efficacy of DKI and DTI to comprehensively evaluate gliomas, compares their results. METHODS: Fifty-two patients (18 females; median age, 47.5 years) with pathologically proved gliomas were prospectively included. All cases underwent DKI examination. DKI (mean kurtosis: MK, axial kurtosis: Ka, radial kurtosis: Kr) and DTI (mean diffusivity: MD, fractional anisotropy: FA) maps of each metric was derived. Three ROIs were manually drawn. RESULTS: MK, Ka, Kr and FA were significantly higher in HGGs than in LGGs, whereas MD was significantly lower in HGGs than in LGGs (P < 0.01). ROC analysis demonstrated that MK (specificity: 100% sensitivity: 79%) and Ka (specificity: 96% sensitivity: 82%) had the same and highest (AUC: 0.93) diagnostic value. Moreover, MK, Ka, and Kr were significantly higher in grade III than II gliomas (P ≦ 0.01). Further, DKI and DTI can significantly identify IDH-1 mutation status (P ≦ 0.03). Ka (sensitivity: 74%, specificity: 75%, AUC: 0.72) showed the highest diagnostic value. In addition, DKI metrics and MD showed significant correlations with Ki-67 (P ≦ 0.01) and Ka had the highest correlation coefficient (rs = 0.72). CONCLUSIONS: Compared with DTI, DKI has great advantages for the comprehensive assessment of gliomas. Ka might serve as a promising imaging index in predicting glioma grading, tumour cell proliferation rate and IDH-1 gene mutation status.

Quantitative analysis of neurite orientation dispersion and density imaging in grading gliomas and detecting IDH-1 gene mutation status.

Background and purpose: Neurite orientation dispersion and density imaging (NODDI) is a new diffusion MRI technique that has rarely been applied for glioma grading. The purpose of this study was to quantitatively evaluate the diagnostic efficiency of NODDI in tumour parenchyma (TP) and peritumoural area (PT) for grading gliomas and detecting isocitrate dehydrogenase-1 (IDH-1) mutation status. Methods: Forty-two patients (male: 23, female: 19, mean age: 44.5 y) were recruited and underwent whole brain NODDI examination. Intracellular volume fraction (icvf) and orientation dispersion index (ODI) maps were derived. Three ROIs were manually placed on TP and PT regions for each case. The corresponding average values of icvf and ODI were calculated, and their diagnostic efficiency was assessed. Results: Tumours with high icvfTP (≥0.306) and low icvfPT (≤0.331) were more likely to be high-grade gliomas (HGGs), while lesions with low icvfTP (<0.306) and high icvfPT (>0.331) were prone to be low-grade gliomas (LGGs) (P < 0.001). A multivariate logistic regression model including patient age and icvf values in TP and PT regions most accurately predicted glioma grade (AUC = 0.92, P < 0.001), with a sensitivity and specificity of 92% and 89%, respectively. However, no significant differences were found in NODDI metrics for differentiating IDH-1 mutation status. Conclusions: The quantitative NODDI metrics in the TP and PT regions are highly valuable for glioma grading. A multivariate logistic regression model using the patient age and the icvf values in TP and PT regions showed very high predictive power. However, the utility of NODDI metrics for detecting IDH-1 mutation status has not been fully explored, as a larger sample size may be necessary to uncover benefits.

The asymmetry of neural symptoms in Wilson's disease patients detecting by diffusion tensor imaging, resting-state functional MRI, and susceptibility-weighted imaging.

Objective: To investigate the cause of the motor asymmetry in Wilson's disease (WD) patients using functional MRI. Methods: Fifty patients with WD and 20 age-matched healthy controls were enrolled. Neurological symptoms were scored using the modified Young Scale. All study subjects underwent diffusion tensor imaging (DTI), susceptibility-weighted imaging (SWI), and resting-state functional MRI (rs-fMRI) of the brain. Six regions of interest (ROI) were chosen. Fiber volumes between ROIs on DTI, corrected phase (CP) values on SWI, amplitude of low-frequency fluctuation (ALFF), and regional homogeneity (REHO) values on rs-fMRI were determined. Asymmetry index (right or left value/left or right value) was evaluated. Results: Asymmetry of rigidity, tremor, choreic movement, and gait abnormality (asymmetry index = 1.33, 1.39, 1.36, 1.40), fiber tracts between the GP and substantia nigra (SN), GP and PU, SN and thalamus (TH), SN and cerebellum, head of the caudate nucleus (CA) and SN, PU and CA, CA and TH, TH and cerebellum (asymmetry index = 1.233, 1.260, 1.269, 1.437, 1.503, 1.138, 1.145, 1.279), CP values in the TH, SN (asymmetry index = 1.327, 1.166), ALFF values, and REHO values of the TH (asymmetry index = 1.192, 1.233) were found. Positive correlation between asymmetry index of rigidity and fiber volumes between the GP and SN, SN and TH (r = .221, .133, p = .043, .036), and tremor and fiber volumes between the CA and TH (r = .045, p = .040) was found. Conclusions: The neurological symptoms of patients with WD were asymmetry. The asymmetry of fiber projections may be the main cause of motor asymmetry in patients with WD.

A study of neurite orientation dispersion and density imaging in wilson's disease.

BACKGROUND: Previous studies have indicated that neurite orientation dispersion and density imaging (NODDI) could be used as a biomarker for detecting microstructural changes of brain. PURPOSE: To quantitatively evaluate the changes in basal ganglia (BG) and thalamus in Wilson's disease (WD) by NODDI and assess the correlation between parameters and disease severity. STUDY TYPE: Prospective case-control study. POPULATION: In total, 24 WD patients and 25 age- and sex-matched normal controls were involved in this study. FIELD STRENGTH/SEQUENCE: EPI diffusion-weighted MR images (b-values = 0, 1000, and 2000 with 30 diffusion gradient directions) were acquired on a 3T scanner. ASSESSMENT: Diffusion data were analyzed using voxel-based analysis. NODDI indices including intracellular volume fraction (Vic), orientation dispersion index (ODI), and isotropic volume fraction (Viso) were estimated from the BG and thalamus. The disease severity was assessed by two experienced neurologists based on the Global Assessment Scale (GAS). The relative importance of NODDI indices in diagnosing WD and predictive accuracy were also analyzed. STATISTICAL TESTING: The Shapiro-Wilk test, Student's t-test, χ2 test, Mann-Whitney-Wilcoxon test, Spearman rank correlation coefficient analysis and random-forest analysis were used for statistical analyses. RESULTS: The Vic and ODI in the BG and thalamus were significantly lower in WD patients than normal controls, while the Viso in the BG and thalamus were significantly higher (P < 0.01). The Vic in the putamen and ODI in the globus pallidus were negatively correlated with clinical severity (rvic = -0.727, P < 0.001; rodi = -0.705, P < 0.001). The Vic in the putamen was the most valuable predictor for diagnosing WD and the prediction accuracy of NODDI was 95.92%. DATA CONCLUSION: NODDI can effectively evaluate the changes of microstructure and metabolism during copper deposition in WD, and thus, it is likely to be useful in detecting the changes in the brain of this disease and assessing its progression. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage 2 J. MAGN. RESON. IMAGING 2018;48:423-430.

Radiosynthesis and Preliminary Biological Evaluation of 18F-Fluoropropionyl-Chlorotoxin as a Potential PET Tracer for Glioma Imaging.

Purposes: Chlorotoxin can specifically bind to matrix metalloproteinase 2 (MMP-2), which are overexpressed in the glioma. In this work, radiosynthesis of [18F]-fluoropropionyl-chlorotoxin ([18F]-FP-chlorotoxin) as a novel PET tracer was investigated, and biodistribution in vivo and PET imaging were performed in the C6 glioma model. Procedures: [18F]-FP-chlorotoxin was prepared from the reaction of chlorotoxin with [18F]-NFB (4-nitrophenyl 2-[18F]-fluoropropionate), which was synthesized from multistep reactions. Biodistribution was determined in 20 normal Kunming mice. Small-animal PET imaging with [18F]-FP-chlorotoxin was performed on the same rats bearing orthotopic C6 glioma at different time points (60 min, 90 min, and 120 min) after injection and compared with 2-deoxy-2-[18F] fluoro-D-glucose ([18F]-FDG). Results: [18F]-FP-Chlorotoxin was successfully synthesized in the radiochemical yield of 41% and the radiochemical purity of more than 98%. Among all the organs, the brain had the lowest and stable uptake of [18F]-FP-chlorotoxin, while the kidney showed the highest uptake. Compared with [18F]-FDG, a low uptake of [18F]-FP-chlorotoxin was detected in normal brain parenchyma and a high accumulation of [18F]-FP-chlorotoxin was found in the gliomas tissue. The glioma to normal brain uptake ratio of [18F]-FP-chlorotoxin was higher than that of [18F]-FDG. Furthermore, the uptake of [18F]-FP-chlorotoxin at 90 min after injection was better than that at 60 min after injection. Conclusions: Compared with [18F]-FDG, [18F]-FP-chlorotoxin has a low and stable uptake in normal brain parenchyma. [18F]-FP-Chlorotoxin seems to be a potential PET tracer with a good performance in diagnosis of the glioma.