Jiashu Zhang

The diagnostic performance of magnetic resonance spectroscopy in differentiating high-from low-grade gliomas: A systematic review and meta-analysis

ObjectiveMagnetic resonance spectroscopy (MRS) is a powerful tool for preoperative grading of gliomas. We performed a meta-analysis to evaluate the diagnostic performance of MRS in differentiating high-grade gliomas (HGGs) from low-grade gliomas (LGGs).MethodsPubMed and Embase databases were systematically searched for relevant studies of glioma grading assessed by MRS through 27 March 2015. Based on the data from eligible studies, pooled sensitivity, specificity, diagnostic odds ratio and areas under summary receiver operating characteristic curve (SROC) of different metabolite ratios were obtained.ResultsThirty articles comprising a total sample size of 1228 patients were included in our meta-analysis. Quantitative synthesis of studies showed that the pooled sensitivity/specificity of Cho/Cr, Cho/NAA and NAA/Cr ratios was 0.75/0.60, 0.80/0.76 and 0.71/0.70, respectively. The area under the curve (AUC) of the SROC was 0.83, 0.87 and 0.78, respectively.ConclusionsMRS demonstrated moderate diagnostic performance in distinguishing HGGs from LGGs using tumoural metabolite ratios including Cho/Cr, Cho/NAA and NAA/Cr. Although there was no significant difference in AUC between Cho/Cr and Cho/NAA groups, Cho/NAA ratio showed higher sensitivity and specificity than Cho/Cr ratio and NAA/Cr ratio. We suggest that MRS should combine other advanced imaging techniques to improve diagnostic accuracy in differentiating HGGs from LGGs.Key points• MRS has moderate diagnostic performance in distinguishing HGGs from LGGs.• There is no significant difference in AUC between Cho/Cr and Cho/NAA ratios.• Cho/NAA ratio is superior to NAA/Cr ratio.• Cho/NAA ratio shows higher sensitivity and specificity than Cho/Cr and NAA/Cr ratios.• MRS should combine other advanced imaging techniques to improve diagnostic accuracy.

Low-Cost Interactive Image-Based Virtual Endoscopy for the Diagnosis and Surgical Planning of Suprasellar Arachnoid Cysts

OBJECTIVE To investigate the feasibility and reliability of virtual endoscopy (VE) as a rapid, low-cost, and interactive tool for the diagnosis and surgical planning of suprasellar arachnoid cysts (SACs). METHODS Eighteen patients with SACs treated with endoscopic ventriculocystostomy were recruited, and 18 endoscopic patients treated with third ventriculostomy were randomly selected as a VE reconstruction control group. After loading their DICOM data into free 3D Slicer software, VE reconstruction was independently performed by 3 blinded clinicians and the time required for each reconstruction was recorded. Another 3 blinded senior neurosurgeons interactively graded the visibility of VE by watching video recordings of the endoscopic procedures. Based on the visibility scores, receiver operating characteristic curve analysis was used to investigate the reliability of VE to diagnose SACs, and Bland-Altman plots were used to assess the reliability of VE for surgical planning. In addition, the intraclass correlation coefficient was calculated to estimate the consistency among the results of 3 reconstruction performers. RESULTS All 3 independent reconstructing performers successfully completed VE simulation for all cases, and the average reconstruction time was 10.2 ± 9.7 minutes. The area under the receiver operating characteristic curve of the cyst visibility score was 0.96, implying its diagnostic value for SACs. The Bland-Altman plot indicated good agreement between VE and intraoperative viewings, suggesting the anatomic accuracy of the VE for surgical planning. In addition, the intraclass correlation coefficient was 0.81, which revealed excellent interperformer consistency of our simulation method. CONCLUSIONS This study substantiated the feasibility and reliability of VE as a rapid, low-cost, and interactive modality for diagnosis and surgical planning of SACs.

A Preliminary Experience with Use of Intraoperative Magnetic Resonance Imaging in Thalamic Glioma Surgery: A Case Series of 38 Patients.

BACKGROUND Thalamic gliomas are rare tumors that constitute 1%-5% of all central nervous system tumors. Despite advanced techniques and equipment, surgical resection remains challenging because of the vital structures adjacent to the tumor. Intraoperative magnetic resonance imaging (MRI) might play an active role during brain tumor surgery because it compensates for brain shift or operation-induced hemorrhage, which are challenging issues for neurosurgeons. METHODS We reviewed 38 patients treated surgically under intraoperative MRI guidance between January 2008 and July 2015 at our center. Preoperative, intraoperative, and postoperative MRI scans were reviewed. Preoperative and postoperative motor power, morbidity and mortality, resection rate, surgical approach, pathologic results, and patient demographics were also reviewed. RESULTS Mean patient age was 37 years ± 18; 12 patients were included in the low-grade group, and 26 patients were included in the high-grade group. Under intraoperative MRI guidance, the gross total resection rate was increased from 16 (42.1%) to 26 (68.4%), and the near-total or subtotal resection rate was increased from 5 (13.2%) to 9 (23.7%). Hematoma formation was discovered in 3 patients on intraoperative MRI scan; each patient underwent a hemostatic operation immediately. CONCLUSIONS With improvements in neurosurgical techniques and equipment, surgical resection is considered feasible in patients with thalamic gliomas. Intraoperative MRI may be helpful in achieving the maximal resection rate with minimal surgical-related morbidity. However, because of severe disease progression, the overall prognosis is unfavorable.

Image-guided endoscopic surgery for spontaneous supratentorial intracerebral hematoma

OBJECTIVE Endoscopic removal of intracerebral hematomas is becoming increasingly common, but there is no standard technique. The authors explored the use of a simple image-guided endoscopic method for removal of spontaneous supratentorial hematomas. METHODS Virtual reality technology based on a hospital picture archiving and communications systems (PACS) was used in 3D hematoma visualization and surgical planning. Augmented reality based on an Android smartphone app, Sina neurosurgical assist, allowed a projection of the hematoma to be seen on the patients scalp to facilitate selection of the best trajectory to the center of the hematoma. A obturator and transparent sheath were used to establish a working channel, and an endoscope and a metal suction apparatus were used to remove the hematoma. RESULTS A total of 25 patients were included in the study, including 18 with putamen hemorrhages and 7 with lobar cerebral hemorrhages. Virtual reality combined with augmented reality helped in achieving the desired position with the obturator and sheath. The median time from the initial surgical incision to completion of closure was 50 minutes (range 40-70 minutes). The actual endoscopic operating time was 30 (range 15-50) minutes. The median blood loss was 80 (range 40-150) ml. No patient experienced postoperative rebleeding. The average hematoma evacuation rate was 97%. The mean (± SD) preoperative Glasgow Coma Scale (GCS) score was 6.7 ± 3.2; 1 week after hematoma evacuation the mean GCS score had improved to 11.9 ± 3.1 (p < 0.01). CONCLUSIONS Virtual reality using hospital PACS and augmented reality with a smartphone app helped precisely localize hematomas and plan the appropriate endoscopic approach. A transparent sheath helped establish a surgical channel, and an endoscope enabled observation of the hematomas location to achieve satisfactory hematoma removal.

Plasticity of language pathways in patients with low-grade glioma: A diffusion tensor imaging study.

Knowledge of the plasticity of language pathways in patients with low-grade glioma is important for neurosurgeons to achieve maximum resection while preserving neurological function. The current study sought to investigate changes in the ventral language pathways in patients with low-grade glioma located in regions likely to affect the dorsal language pathways. The results revealed no significant difference in fractional anisotropy values in the arcuate fasciculus between groups or between hemispheres. However, fractional anisotropy and lateralization index values in the left inferior longitudinal fasciculus and lateralization index values in the left inferior fronto-occpital fasciculus were higher in patients than in healthy subjects. These results indicate plasticity of language pathways in patients with low-grade glioma. The ventral language pathways may perform more functions in patients than in healthy subjects. As such, it is important to protect the ventral language pathways intraoperatively.

Intraoperative diffusion tensor imaging predicts the recovery of motor dysfunction after insular lesions

Insular lesions remain surgically challenging because of the need to balance aggressive resection and functional protection. Motor function deficits due to corticospinal tract injury are a common complication of surgery for lesions adjacent to the internal capsule and it is therefore essential to evaluate the corticospinal tract adjacent to the lesion. We used diffusion tensor imaging to evaluate the corticospinal tract in 89 patients with insular lobe lesions who underwent surgery in Chinese PLA General Hospital from February 2009 to May 2011. Postoperative motor function evaluation revealed that 57 patients had no changes in motor function, and 32 patients suffered motor dysfunction or aggravated motor dysfunction. Of the affected patients, 20 recovered motor function during the 6–12-month follow-up, and an additional 12 patients did not recover over more than 12 months of follow-up. Following reconstruction of the corticospinal tract, fractional anisotropy comparison demonstrated that preoperative, intraoperative and follow-up normalized fractional anisotropy in the stable group was higher than in the transient deficits group or the long-term deficits group. Compared with the transient deficits group, intraoperative normalized fractional anisotropy significantly decreased in the long-term deficits group. We conclude that intraoperative fractional anisotropy values of the corticospinal tracts can be used as a prognostic indicator of motor function outcome.

Integrated functional neuronavigation-guided resection of small meningiomas of the atrium via the paramedian parieto-occipital approach.

OBJECTIVE Small meningiomas located in the atrium of the lateral ventricle remain a challenge for neurosurgeons due to the eloquent nature of the surrounding anatomy. Functional MRI (fMRI) and diffusion tensor tractography (DTT) allow for in vivo demonstrations of eloquent cortical structures and neuronal fiber tracts, respectively. Our objective is to evaluate the contribution of functional neuronavigation combined with fMRI and DTT results to surgical outcomes. MATERIALS AND METHODS we investigated 11 patients with small meningiomas located in the atrium of the lateral ventricle who underwent surgery with the aid of functional neuronavigation via the paramedian parieto-occipital approach. The patients willingly underwent assessments of neurologic deficits preoperatively and postoperatively at discharge and at three months after surgery. RESULTS Gross total resection was achieved in all patients, and no residual or recurrent tumors were observed on follow-up imaging. There was no mortality. Only one patient suffered from transient postoperative aphasia (mild to moderate) that was resolved one week after surgery. No novel neurologic deficits were present in any of the other patients, and no new-onset epileptic attacks were observed. CONCLUSIONS With the aid of the neuronavigation that incorporates fMRI and DTT results, small meningiomas located in the atrium of the lateral ventricle can be safely resected through the paramedian parieto-occipital approach.

Multimodal Image-based Virtual Reality Pre-surgical Simulation and Evaluation for Trigeminal Neuralgia and Hemi-facial Spasm

OBJECTIVE To address the feasibility and predictive value of multimodal image-based virtual reality in detecting and assessing features of neurovascular confliction (NVC), particularly regarding the detection of offending vessels, degree of compression exerted on the nerve root, in patients who underwent microvascular decompression for nonlesional trigeminal neuralgia and hemifacial spasm (HFS). METHODS This prospective study includes 42 consecutive patients who underwent microvascular decompression for classic primary trigeminal neuralgia or HFS. All patients underwent preoperative 1.5-T magnetic resonance imaging (MRI) with T2-weighted three-dimensional (3D) sampling perfection with application-optimized contrasts by using different flip angle evolutions, 3D time-of-flight magnetic resonance angiography, and 3D T1-weighted gadolinium-enhanced sequences in combination, whereas 2 patients underwent extra experimental preoperative 7.0-T MRI scans with the same imaging protocol. Multimodal MRIs were then coregistered with open-source software 3D Slicer, followed by 3D image reconstruction to generate virtual reality (VR) images for detection of possible NVC in the cerebellopontine angle. Evaluations were performed by 2 reviewers and compared with the intraoperative findings. RESULTS For detection of NVC, multimodal image-based VR sensitivity was 97.6% (40/41) and specificity was 100% (1/1). Compared with the intraoperative findings, the κ coefficients for predicting the offending vessel and the degree of compression were >0.75 (P < 0.001). The 7.0-T scans have a clearer view of vessels in the cerebellopontine angle, which may have significant impact on detection of small-caliber offending vessels with relatively slow flow speed in cases of HFS. CONCLUSIONS Multimodal image-based VR using 3D sampling perfection with application-optimized contrasts by using different flip angle evolutions in combination with 3D time-of-flight magnetic resonance angiography sequences proved to be reliable in detecting NVC and in predicting the degree of root compression. The VR image-based simulation correlated well with the real surgical view.

Intraoperative visualisation of functional structures facilitates safe frameless stereotactic biopsy in the motor eloquent regions of the brain

Abstract Background: For stereotactic brain biopsy involving motor eloquent regions, the surgical objective is to enhance diagnostic yield and preserve neurological function. To achieve this aim, we implemented functional neuro-navigation and intraoperative magnetic resonance imaging (iMRI) into the biopsy procedure. The impact of this integrated technique on the surgical outcome and postoperative neurological function was investigated and evaluated. Method: Thirty nine patients with lesions involving motor eloquent structures underwent frameless stereotactic biopsy assisted by functional neuro-navigation and iMRI. Intraoperative visualisation was realised by integrating anatomical and functional information into a navigation framework to improve biopsy trajectories and preserve eloquent structures. iMRI was conducted to guarantee the biopsy accuracy and detect intraoperative complications. The perioperative change of motor function and biopsy error before and after iMRI were recorded, and the role of functional information in trajectory selection and the relationship between the distance from sampling site to nearby eloquent structures and the neurological deterioration were further analyzed. Results: Functional neuro-navigation helped modify the original trajectories and sampling sites in 35.90% (16/39) of cases to avoid the damage of eloquent structures. Even though all the lesions were high-risk of causing neurological deficits, no significant difference was found between preoperative and postoperative muscle strength. After data analysis, 3mm was supposed to be the safe distance for avoiding transient neurological deterioration. During surgery, the use of iMRI significantly reduced the biopsy errors (p = 0.042) and potentially increased the diagnostic yield from 84.62% (33/39) to 94.87% (37/39). Moreover, iMRI detected intraoperative haemorrhage in 5.13% (2/39) of patients, all of them benefited from the intraoperative strategies based on iMRI findings. Conclusions: Intraoperative visualisation of functional structures could be a feasible, safe and effective technique. Combined with intraoperative high-field MRI, it contributed to enhance the biopsy accuracy and lower neurological complications in stereotactic brain biopsy involving motor eloquent areas.

Role of magnetic resonance spectroscopy to differentiate high-grade gliomas from metastases:

This study is to measure the diagnostic examination quality of magnetic resonance spectroscopy in differentiating high-grade gliomas from metastases. PubMed, Embase, and Chinese Biomedical databases were systematically searched for relevant studies published through 10 July 2016. Based on the data from eligible studies, heterogeneity and threshold effect tests were performed; pooled sensitivity, specificity, and areas under summary receiver-operating characteristic curve of magnetic resonance spectroscopy were calculated. Finally, seven studies with a total of 261 patients were included. Quantitative synthesis of studies showed that pooled sensitivity/specificity of Cho/NAA and Cho/Cr ratio in peritumoral region was 0.85 (95% confidence interval: 0.79–0.90)/0.93 (95% confidence interval: 0.80–0.99) and 0.86 (95% confidence interval: 0.76–0.92)/0.86 (95% confidence interval: 0.73–0.94). The area under the curve of the summary receiver-operating characteristic curve was 0.95 and 0.90. Pooled sensitivity, specificity, and area under the curve of magnetic resonance spectroscopy to identify high-grade gliomas from metastases were 0.85 (95% confidence interval: 0.79–0.90), 0.84 (95% confidence interval: 0.75–0.90), and 0.90, respectively. We concluded that magnetic resonance spectroscopy demonstrated moderate diagnostic performance in distinguishing high-grade gliomas from metastases. Furthermore, Cho/NAA ratio showed higher specificity and higher value of area under the curve than Cho/Cr ratio in peritumoral region. We suggest that Cho/NAA ratio of peritumoral region should be used to improve diagnostic accuracy of magnetic resonance spectroscopy for differentiating high-grade gliomas from metastases.