Feina Shi

Apparent diffusion coefficient maps obtained from high b value diffusion-weighted imaging in the preoperative evaluation of gliomas at 3T: comparison with standard b value diffusion-weighted imaging

AbstractObjectiveTo assess whether ADC maps obtained from high b value DWI were more valuable in preoperatively evaluating the grade, Ki-67 index and outcome of gliomas.MethodsSixty-three patients with gliomas, who underwent preoperative multi b value DWI at 3xa0T, were enrolled. The ADC1000, ADC2000 and ADC3000 maps were generated. Receiver operating characteristic analyses were conducted to determine the area under the curve (AUC) in differentiating high-grade gliomas (HGG) from low-grade gliomas (LGG). Pearson correlation coefficients (R value) were calculated to investigate the correlation between parameters with the Ki-67 proliferation index. Survival analysis was conducted by using Cox regression.ResultsThe AUC of the mean ADC1000 value (0.820) was lower than that of the mean ADC2000 value (0.847) and mean ADC3000 value (0.875) in differentiating HGG from LGG. The R value of the mean ADC1000 value (−0.499) was less negative than that of the mean ADC2000 value (−0.530) and mean ADC3000 value (−0.567). The mean ADC3000 value was an independent prognosis factor for gliomas (pu2009=u20090.008), while the mean ADC1000 and ADC2000 values were not.ConclusionADC maps obtained from high b value DWI might be a better imaging biomarker in the preoperative evaluation of gliomas.Key Points• ADC3000maps could improve the differentiation between HGG and LGG.n • The mean ADC3000value had a closer correlation with the Ki-67 index.n • The mean ADC3000value was an independent prognosis factor for gliomas.

3D Pseudocontinuous Arterial Spin-Labeling MR Imaging in the Preoperative Evaluation of Gliomas

Fifty-eight patients with pathologically confirmed gliomas underwent preoperative 3D pseudocontinuous arterial spin-labeling and ROC curves were generated for parameters to distinguish high-grade from low-grade gliomas. Both maximum CBF and maximum relative CBF were significantly higher in high-grade than in low-grade gliomas. After adjustment for age, a higher maximum CBF and higher maximum relative CBF were associated with worse progression-free survival. BACKGROUND AND PURPOSE: Previous studies showed conflicting results concerning the value of CBF maps obtained from arterial spin-labeling MR imaging in grading gliomas. This study was performed to investigate the effectiveness of CBF maps derived from 3D pseudocontinuous arterial spin-labeling in preoperatively assessing the grade, cellular proliferation, and prognosis of gliomas. MATERIALS AND METHODS: Fifty-eight patients with pathologically confirmed gliomas underwent preoperative 3D pseudocontinuous arterial spin-labeling. The receiver operating characteristic curves for parameters to distinguish high-grade gliomas from low-grade gliomas were generated. Pearson correlation analysis was used to assess the correlation among parameters. Survival analysis was conducted with Cox regression. RESULTS: Both maximum CBF and maximum relative CBF were significantly higher in high-grade gliomas than in low-grade gliomas (P < .001). The areas under the curve for maximum CBF and maximum relative CBF in distinguishing high-grade gliomas from low-grade gliomas were 0.828 and 0.863, respectively. Both maximum CBF and maximum relative CBF had no correlation with the Ki-67 index in all subjects and had a moderate negative correlation with the Ki-67 index in glioblastomas (r = −0.475, −0.534, respectively). After adjustment for age, a higher maximum CBF (P = .008) and higher maximum relative CBF (P = .005) were associated with worse progression-free survival in gliomas, while a higher maximum relative CBF (P = .033) was associated with better overall survival in glioblastomas. CONCLUSIONS: 3D pseudocontinuous arterial spin-labeling–derived CBF maps are effective in preoperative evaluation of gliomas. Although gliomas with a higher blood flow are more malignant, glioblastomas with a lower blood flow are likely to be more aggressive.

Glioma infiltration sign on high b-value diffusion-weighted imaging in gliomas and its prognostic value: Glioma Infiltration Sign on DWI

Glioma cells may infiltrate beyond the tumor margins revealed on conventional structural images.

Reperfusion facilitates reversible disruption of the human blood–brain barrier following acute ischaemic stroke

AbstractObjectivesWe aimed to detect early changes of the blood–brain barrier permeability (BBBP) in acute ischaemic stroke (AIS), with or without reperfusion, and find out whether BBBP can predict clinical outcomes.MethodsConsecutive AIS patients imaged with computed tomographic perfusion (CTP) before and 24 h after treatment were included. The relative permeability–surface area product (rPS) was calculated within the hypoperfused region (rPShypo-i), non-hypoperfused region of ischaemic hemisphere (rPSnonhypo-i) and their contralateral mirror regions (rPShypo-c and rPSnonhypo-c). The changes of rPS were analysed using analysis of variance (ANOVA) with repeated measures. Logistic regression was used to identify independent predictors of unfavourable outcome.ResultsFifty-six patients were included in the analysis, median age was 76 (IQR 62–81) years and 28 (50%) were female. From baseline to 24 h after treatment, rPShypo-i, rPSnonhypo-i and rPShypo-c all decreased significantly. The decreases in rPShypo-i and rPShypo-c were larger in the reperfusion group than non-reperfusion group. The rPShypo-i at follow-up was a predictor for unfavourable outcome (OR 1.131; 95% CI 1.018–1.256; P = 0.022).ConclusionEarly disruption of BBB in AIS is reversible, particularly when greater reperfusion is achieved. Elevated BBBP at 24 h after treatment, not the pretreatment BBBP, predicts unfavourable outcome.Key points• Early disruption of blood–brain barrier (BBB) in stroke is reversible after treatment.n • The reversibility of BBB permeability is associated with reperfusion.n • Unfavourable outcome is associated with BBB permeability at 24 h after treatment.n • Contralateral non-ischaemic hemisphere is not ‘normal’ during an acute stroke.

Number of Fractured Calvarial Bones Predicts Outcome in Traumatic Brain Injury Patients After Early Craniotomy

BACKGROUNDnPrognostic markers are important for neurosurgeons to evaluate the indications for aggressive surgical management. The purpose of this study was to investigate whether the number of fractured calvarial bones could predict the outcome in patients with traumatic brain injury (TBI) after early craniotomy.nnnMETHODSnTBI patients who underwent early craniotomy were reviewed. The number of fractured calvarial bones was recorded by referring to preoperative computed tomographic (CT) images. Accordingly, patients were assigned to no calvarial fracture group, single calvarial fracture group, and multiple calvarial fractures group. Good outcome was defined as Glasgow Outcome Scale scores of 4 and 5 at discharge. Logistic regression analyses were used to assess the effect of calvarial fracture on outcome. A receiver operating characteristic curve was generated for the final model.nnnRESULTSnIn all, a total of 141 patients were enrolled. Patients with no calvarial fracture had a significantly lower rate of good outcome (12.5%) than did those with a single calvarial fracture (62.2%, P < 0.001) and those with multiple calvarial fractures (48.6%, Pxa0= 0.005). Binary logistic regression showed that the number of fractured calvarial bones was an independent imaging marker for predicting outcome (Pxa0= 0.003) after adjustment for age, Glasgow Coma Scale score on admission, and decompressive craniectomy. The area under the curve of the final model was 0.863.nnnCONCLUSIONSnThe number of fractured calvarial bones is an independent predictor of outcome in TBI patients after early craniotomy. No calvarial facture is associated with poor outcome in these patients.

Pseudo-Occlusion of the Internal Carotid Artery Predicts Poor Outcome After Reperfusion Therapy

Background and Purpose— This study aimed to evaluate the occurrence rate of the internal carotid artery pseudo-occlusion (ICA-PO) on 4-dimensional–computed tomography angiography and to investigate its relationship with clinical outcome after reperfusion therapy. Methods— In this case–control study, we retrospectively reviewed our prospectively collected database for consecutive acute ischemic stroke patients who received reperfusion therapy between June 2009 and February 2017. ICA-PO was defined when the arterial segment was not opacified on peak arterial phase yet was subsequently patent after artery peak phase on 4-dimensional–computed tomography angiography. Poor outcome was defined as 3-month modified Rankin Scale of 4 to 6. Binary logistic regression was used to investigate the relationship of ICA-PO with poor outcome and the rate of reperfusion, respectively. Results— A total of 143 patients with isolated middle cerebral artery occlusion were included and 30 (21.0%) had ICA-PO. Patients with ICA-PO were more likely to have poor outcome (80.0% versus 37.2%; P<0.001) and a lower rate of reperfusion (45.8% versus 69.0%; P=0.033) than those without. Binary logistic regression revealed that ICA-PO was independently associated with poor outcome (odds ratio, 7.957; 95% confidence interval, 1.655–34.869; P=0.009) and reperfusion at 24 hours (odds ratio, 0.150; 95% confidence interval, 0.045–0.500; P=0.002) after adjustment. Among patients with no reperfusion, all ICA-PO patients obtained poor outcome, whereas only 45.2% non-PO patients underwent poor outcome (P=0.001). Conclusions— Four dimensional-computed tomography angiography is a useful noninvasive technique to identify ICA-PO. Patients with ICA-PO are prone to undergo poor outcome from reperfusion therapy, especially when reperfusion is not achieved.

Increased blood-brain barrier permeability in contralateral hemisphere predicts worse outcome in acute ischemic stroke after reperfusion therapy

Aims We sought to investigate the risk factors of blood-brain barrier (BBB) disruption, and its potential impact on 90-day clinical outcome in acute ischemic stroke (AIS) patients after reperfusion therapy. Methods Consecutive acute anterior circulation AIS patients imaged with computed tomographic perfusion (CTP) before reperfusion therapy were included. Tmax >6u2009s was used for the volumetric measurement of the hypoperfusion area. BBB permeability (BBBP) was calculated as the average relative permeability-surface area product (rPS) within the hypoperfusion region (rPShypo-i) and its contralateral mirror region (rPShypo-c) on CTP-derived PS color maps. Modified Rankin Scale (mRS) score was obtained at 90-day post-stroke. Results A total of 187 patients were included, among whom the median age was 73 (61–80) years and 76 (40.6%) were women. Median baseline NIHSS score was 12 (7– 16). Ninety-eight (52.4%) patients had mRS scoreu2009>2. Increased rPShypo-i and rPShypo-c were both independently associated with males and large infarct volume. The increased rPShypo-i was also independently associated with a history of atrial fibrillation and high NIHSS score. Multivariable analysis showed higher rPShypo-c was independently associated with higher mRS (OR: 1.064, 95%u2009CI 1.011 to 1.121; P=0.018). Conclusion BBBP in both the hypoperfusion region and its contralateral mirror region are associated with stroke severity, but only increased BBBP in the contralateral mirror hypoperfusion region relates to worse outcome after reperfusion therapy.

A Modified Tri-Exponential Model for Multi-b-value Diffusion-Weighted Imaging: A Method to Detect the Strictly Diffusion-Limited Compartment in Brain

Purpose: To present a new modified tri-exponential model for diffusion-weighted imaging (DWI) to detect the strictly diffusion-limited compartment, and to compare it with the conventional bi- and tri-exponential models. Methods: Multi-b-value diffusion-weighted imaging (DWI) with 17 b-values up to 8,000 s/mm2 were performed on six volunteers. The corrected Akaike information criterions (AICc) and squared predicted errors (SPE) were calculated to compare these three models. Results: The mean f0 values were ranging 11.9–18.7% in white matter ROIs and 1.2–2.7% in gray matter ROIs. In all white matter ROIs: the AICcs of the modified tri-exponential model were the lowest (p < 0.05 for five ROIs), indicating the new model has the best fit among these models; the SPEs of the bi-exponential model were the highest (p < 0.05), suggesting the bi-exponential model is unable to predict the signal intensity at ultra-high b-value. The mean ADCvery−slow values were extremely low in white matter (1–7 × 10−6 mm2/s), but not in gray matter (251–445 × 10−6 mm2/s), indicating that the conventional tri-exponential model fails to represent a special compartment. Conclusions: The strictly diffusion-limited compartment may be an important component in white matter. The new model fits better than the other two models, and may provide additional information.

Severe Blood–Brain Barrier Disruption in Cardioembolic Stroke

Background Previous studies demonstrated that cardioembolism (CE) was prone to develop hemorrhagic transformation (HT), whereas hyper-permeability of blood–brain barrier (BBB) might be one reason for the development of HT. We, thus, aimed to investigate whether the BBB permeability (BBBP) was higher in CE stroke than other stroke subtypes in acute ischemic stroke (AIS) patients. Methods This study was a retrospective review of prospectively collected clinical and imaging database of AIS patients who underwent CT perfusion. Hypoperfusion was defined as Tmax >6u2009s. The average relative permeability-surface area product (rPS), reflecting the BBBP, was calculated within the hypoperfusion region (rPShypo). CE was diagnosed according to the international Trial of Org 10172 in Acute Stroke Treatment criteria. Receiver operating characteristics (ROC) curve analysis was used to determine predictive value of rPShypo for CE. Logistic regression was used to identify independent predictors for CE. Results A total of 187 patients were included in the final analysis [median age, 73 (61–80) years; 75 (40.1%) females; median baseline National Institutes of Health Stroke Scale score, 12 (7–16)]. Median rPShypo was 65.5 (35.8–110.1)%. Ninety-seven (51.9%) patients were diagnosed as CE. ROC analysis revealed that the optimal rPShypo threshold for CE was 86.71%. The value of rPShypo and the rate of rPShypo>86.71% were significantly higher in patients with CE than other stroke subtypes (pu2009<u20090.05), after adjusting for the potential confounds. Conclusion The extent of BBB disruption is more severe in CE stroke than other stroke subtypes during the hyperacute stage.

Corrigendum: Novel Prehospital Prediction Model of Large Vessel Occlusion Using Artificial Neural Network

[This corrects the article DOI: 10.3389/fnagi.2018.00181.].