Shijun Qiu

Magnetic Resonance Imaging of Primary Cerebral Gliosarcoma: A Report of 15 Cases

Background: Gliosarcomas are rare tumors with mixed glial and mesenchymal components. Many of their radiologic features resemble those of other primary brain malignancies. Purpose: To investigate the magnetic resonance (MR) imaging features of gliosarcomas. Material and Methods: We retrospectively reviewed the MR images, pathology reports, and clinical information of 11 male and four female patients aged 15–71 years to evaluate the location, morphology, enhancement, and other features of their pathologically confirmed gliosarcomas. Results: Apart from one tumor in the right cerebellar hemisphere, all were supratentorial. Two tumors were intraventricular, and four involved the corpus callosum. The tumors were well demarcated, with an inhomogeneous or cystic appearance and moderate-to-extensive surrounding edema. Thick walls with strong rim and ring-like enhancement were observed in 13 (87%). Seven (47%) showed intratumoral paliform enhancement. Conclusion: Gliosarcoma demonstrates certain characteristic MR features, such as supratentorial and peripheral location, well-demarcated, abutting a dural surface, uneven and thick-walled rim-like or ring enhancement, as well as intratumoral strip enhancement. These findings, combined with patient age, can aid the differential diagnosis of gliosarcomas from more common primary brain tumors.

Disrupted topological properties of brain white matter networks in left temporal lobe epilepsy: A diffusion tensor imaging study

Mesial temporal lobe epilepsy (mTLE) is the most common drug-refractory focal epilepsy in adults. Although previous functional and morphological studies have revealed abnormalities in the brain networks of mTLE, the topological organization of the brain white matter (WM) networks in mTLE patients is still ambiguous. In this study, we constructed brain WM networks for 14 left mTLE patients and 22 age- and gender-matched normal controls using diffusion tensor tractography and estimated the alterations of network properties in the mTLE brain networks using graph theoretical analysis. We found that networks for both the mTLE patients and the controls exhibited prominent small-world properties, suggesting a balanced topology of integration and segregation. However, the brain WM networks of mTLE patients showed a significant increased characteristic path length but significant decreased global efficiency, which indicate a disruption in the organization of the brain WM networks in mTLE patients. Moreover, we found significant between-group differences in the nodal properties in several brain regions, such as the left superior temporal gyrus, left hippocampus, the right occipital and right temporal cortices. The robustness analysis showed that the results were likely to be consistent for the networks constructed with different definitions of node and edge weight. Taken together, our findings may suggest an adverse effect of epileptic seizures on the organization of large-scale brain WM networks in mTLE patients.

Multivariate pattern analysis reveals anatomical connectivity differences between the left and right mesial temporal lobe epilepsy

Previous studies have demonstrated differences of clinical signs and functional brain network organizations between the left and right mesial temporal lobe epilepsy (mTLE), but the anatomical connectivity differences underlying functional variance between the left and right mTLE remain uncharacterized. We examined 43 (22 left, 21 right) mTLE patients with hippocampal sclerosis and 39 healthy controls using diffusion tensor imaging. After the whole-brain anatomical networks were constructed for each subject, multivariate pattern analysis was applied to classify the left mTLE from the right mTLE and extract the anatomical connectivity differences between the left and right mTLE patients. The classification results reveal 93.0% accuracy for the left mTLE versus the right mTLE, 93.4% accuracy for the left mTLE versus controls and 90.0% accuracy for the right mTLE versus controls. Compared with the right mTLE, the left mTLE exhibited a different connectivity pattern in the cortical-limbic network and cerebellum. The majority of the most discriminating anatomical connections were located within or across the cortical-limbic network and cerebellum, thereby indicating that these disease-related anatomical network alterations may give rise to a portion of the complex of emotional and memory deficit between the left and right mTLE. Moreover, the orbitofrontal gyrus, cingulate cortex, hippocampus and parahippocampal gyrus, which exhibit high discriminative power in classification, may play critical roles in the pathophysiology of mTLE. The current study demonstrated that anatomical connectivity differences between the left mTLE and the right mTLE may have the potential to serve as a neuroimaging biomarker to guide personalized diagnosis of the left and right mTLE.

Imaging characteristics of primary intracranial teratoma.

Background Primary intracranial teratomas are rare intracranial neoplasms, and are subdivided into mature, immature, and those with malignant transformation. To date, only a few studies of teratoma imaging have been reported. Purpose To describe and characterize the magnetic resonance imaging (MRI) findings in a series of 18 patients (16 men/boys and 2 women/girls; mean age, 14.5 years) with pathologically proven teratomas. Material and Methods Findings from medical records and imaging examinations in 18 patients with pathologically confirmed intracranial teratomas from 2001 to 2011were retrospectively reviewed at our two institutions. Two radiologists evaluated the lesion location, shape, size, number, edge, homogeneous or heterogeneous appearance, attenuation, signal intensity, and degree of enhancement. Results All tumors were located within the pineal (n = 13), parasellar (n = 2), or suprasellar (n = 3) regions. The lesions appeared of mixed intensity on MRI, reflecting the histologic heterogeneity, including fibrosis, fatty tissue, calcification, cysts, and keratinocytes. In mature teratomas (n = 9), seven of nine tumors showed non-enhanced multilocularity or heterogeneous enhancement of the cyst wall on contrast-enhanced T1-weighted (T1W) images. Two of nine tumors showed moderate, heterogeneous enhancement in the solid portion of the lesion; whereas in immature (n = 7) or malignant transformation (n = 2) teratomas, heterogeneous, ring-like, intratumoral patchy enhancement was noted on T1W images with contrast. Conclusion Primary intracranial teratomas are usually localized in the pineal and the suprasellar regions, and often present an ovoid or lobulated mass with or without multilocularity on MRI. Marked enhancement of the solid portion or the thick wall of the tumor was the key feature for distinguishing mature teratoma and malignant teratoma.

Characteristic CT and MRI findings of intracranial chondroma

Background Intracranial chondromas are rare benign tumors. To date, few data are available on their neuroradiological features. Purpose To describe a series of patients with intracranial chondroma and to analyze and discuss the computed tomography (CT) and magnetic resonance imaging (MRI) features that may distinguish chondromas from other intracranial neoplasms. Material and Methods We retrospectively analyzed clinical and medical imaging data of six patients who had pathologically confirmed intracranial chondromas in our two institutions between July 2006 and September 2011. Both CT and MRI scanning were performed in all six cases. Results Five tumors were located at the skull base and one originated from the falx. CT images revealed well-demarcated, irregular lobulated and variable density masses with obvious calcification (6/6), no or slight enhancement, without peritumoral edema, and frequently accompanied by erosion and destruction of surrounding bone (5/6). Tumor parenchyma appeared heterogeneously hypointense on T1WI, and hyperintense or mixed hyperintense and hypointense on T2WI, while the calcification appeared hypointense on T1WI and T2WI in five cases, demonstrating significant inhomogeneous enhancement on postcontrast MRI, which revealed the typical “punica granatum seeds” sign. Only one case showed homogeneous low signal intensity on T1WI and high signal intensity on T2WI, and relatively uniform obvious enhancement on postcontrast scans. Conclusion These characteristic CT and MR findings, combined with the location of the lesions and the history of a long duration of clinical symptoms, may prove helpful in differentiating intracranial chondromas from other more common tumors.

Decreased white matter integrity in mesial temporal lobe epilepsy: a machine learning approach.

Statistical analysis on diffusion tensor imaging has been used extensively in mesial temporal lobe epilepsy (mTLE) and most studies report decrease in fractional anisotropy (FA) in multiple white matter regions. However, these findings vary across studies and between regions. Therefore, in this study, we used tract-based spatial statistics along with machine learning approaches to investigate the whole-brain white matter changes between 17 left mTLE patients and 15 right mTLE patients and 34 matched healthy controls. The results showed that the three groups could be distinguished from each other with promising accuracy. Compared with controls, the FA value of the most discriminating voxels was decreased in the ipsilateral limbic system, corpus callosum, and temporal white matter in both patient groups. Compared with right mTLE, left mTLE had decreased FA in the left temporal white matter, whereas right mTLE had decreased FA in the right frontal and temporal white matter, and right posterior corona radiata. These findings not only provide useful information for lateralization of the seizure focus but can also be used as a potential biomarker for the diagnosis and treatment of the mTLE. This may be helpful in assessment of patients with mTLE when no lesion is detected on visual evaluation.

Extratemporal abnormalities of brain parenchyma in young adults with temporal lobe epilepsy: A diffusion tensor imaging study

AIM To examine extratemporal abnormalities of the cerebral parenchyma in young adult temporal lobe epilepsy (TLE) patients using diffusion tensor imaging (DTI). MATERIALS AND METHODS The study comprised 20 adults with unilateral TLE and 20 controls. The fractional anisotropy (FA), apparent diffusion coefficient (ADC), parallel eigenvalue (λ∥), and perpendicular eigenvalue (λ⊥) were calculated in the regions of interest (ROIs) using a 3 T MRI system. ROIs included the anterior/posterior limb of the internal capsule (AIC/PIC), external capsule (EC), head of caudate nucleus (HCN), lenticular nucleus (LN), thalamus (TL), and genu/body/splenium of the corpus callosum (GCC/BCC/SCC). RESULTS Compared to controls, TLE patients showed lower FA in all ROIs; higher ADC in bilateral ECs, HCNs, TLs, and BCC; lower λ∥ in the ipsilateral LN and bilateral AICs, TL, and GCC; and higher λ⊥ in all ROIs except the bilateral PICs. In TLE patients, the ipsilateral TL had decreased FA compared with the contralateral TL. Pearson correlation analysis revealed a negative correlation between the ADC of the GCC and the age at onset of epilepsy; the λ∥ of the ipsilateral PIC and age at onset of epilepsy; the λ⊥ of the contralateral AIC and duration of epilepsy, respectively; and a positive correlation between the ADC of the GCC and the duration of epilepsy and the λ⊥ of the GCC and the duration of epilepsy, respectively. CONCLUSION The study revealed bilateral extratemporal abnormalities in young adult TLE patients compared with controls. In addition, TLE patients with younger age at onset or longer duration of epilepsy may have more serious extratemporal changes.

Radiation-induced functional connectivity alterations in nasopharyngeal carcinoma patients with radiotherapy.

AbstractThe study aims to investigate the radiation-induced brain functional alterations in nasopharyngeal carcinoma (NPC) patients who received radiotherapy (RT) using functional magnetic resonance imaging (fMRI) and statistic scale.The fMRI data of 35 NPC patients with RT and 24 demographically matched untreated NPC patients were acquired. Montreal Cognitive Assessment (MoCA) was also measured to evaluate their global cognition performance. Multivariate pattern analysis was performed to find the significantly altered functional connections between these 2 groups, while the linear correlation level was detected between the altered functional connections and the MoCA scores.Forty-five notably altered functional connections were found, which were mainly located between 3 brain networks, the cerebellum, sensorimotor, and cingulo-opercular. With strictly false discovery rate correction, 5 altered functional connections were shown to have significant linear correlations with the MoCA scores, that is, the connections between the vermis and hippocampus, cerebellum lobule VI and dorsolateral prefrontal cortex, precuneus and dorsal frontal cortex, cuneus and middle occipital lobe, and insula and cuneus. Besides, the connectivity between the vermis and hippocampus was also significantly correlated with the attention score, 1 of the 7 subscores of the MoCA.The present study provides new insights into the radiation-induced functional connectivity impairments in NPC patients. The results showed that the RT may induce the cognitive impairments, especially the attention alterations. The 45 altered functional connections, especially the 5 altered functional connections that were significantly correlated to the MoCA scores, may serve as the potential biomarkers of the RT-induced brain functional impairments and provide valuable targets for further functional recovery treatment.

Structural MRI research in patients with nasopharyngeal carcinoma following radiotherapy: A DTI and VBM study

The aim of the present study was to investigate the microstructural characteristics of the brain lobes following radiotherapy (RT) for patients with nasopharyngeal carcinoma (NPC) at distinct times. Diffusion tensor imaging (DTI) and 3D-T1-weighted imaging was performed in 70 age- and sex-matched subjects, 24 of whom were pre-treatment patients. The patients were divided into three groups, according to the time following completion of RT. Fractional anisotropy (FA) and gray matter (GM) volume were determined. The DTI data were analyzed using tract-based spatial statistics and the GM volume was analyzed using voxel-based morphometry (VBM). Compared with the pre-RT group, the mean FA values in the left parietal lobe white matter (WM) and right cerebellum decreased significantly in the post-RT 0-6 month group (P<0.05). In addition, the mean FA values in the right parietal lobe WM decreased significantly in the post-RT 6-12 month group (P<0.05), compared with the pre-RT group. The FA level in the right temporal lobe remained significantly decreased, compared with that in the pre-RT group (P<0.05) for 1 year after RT. Furthermore, compared with pre-RT group, the GM volume in the bilateral frontal lobe, right occipital lobe, left parietal lobe, right temporal lobe and left cerebellum decreased significantly in the post-RT 0-6 month group (P<0.05), and in the bilateral temporal lobe, parietal lobe, right frontal lobe and left cerebellum, the GM volume decreased significantly in the post-RT 6-12 month group (P<0.05). The GM volume in the right temporal lobe, bilateral frontal lobe and bilateral cerebellum remained significantly decreased compared with that in the pre-RT group (P<0.05) for 1 year after RT. A combination of DTI and VBM may be used to determine radiation-induced brain injury in patients treated for NPC.

Radiation-induced cerebellar–cerebral functional connectivity alterations in nasopharyngeal carcinoma patients

The current study aimed to investigate the altered cerebellar–cerebral functional connectivity (FC) induced by radiotherapy to nasopharyngeal carcinoma (NPC) patients. Twenty-four NPC patients without treatment, and 35 NPC patients receiving radiotherapy underwent functional MRI scanning. Montreal cognitive assessment (MoCA) was performed to evaluate the cognitive status of all participants. FC between 10 predefined cerebellar seeds, which were demonstrated to be involved in different brain functional networks, and all brain voxels was obtained for each participant. Using a second-level two-sample t-test, three significantly different FCs between the two patient groups were found, including the connections between the left lobule VIII and the right medial frontal gyrus, the left lobule VIII and the right crus I, and the right lobule VIIb and the right fusiform gyrus. The altered cerebellar–cerebral FCs were also significantly correlated to the MoCA score, as well as the attention score, one of the seven subscores in MoCA. We suggested that the altered cerebellar–cerebral FCs may underlie the radiation-induced cognitive deficits in NPC patients, especially in the domain of attention. Furthermore, considering the functional networks in which the altered connections involved, the anticorrelation between the default network and dorsal attention network may be impaired, and the mediating function of the frontoparietal network to dorsal attention network may be disrupted. The significantly altered cerebellar–cerebral FC may serve as the potential biomarker in revealing the radiation-induced functional abnormalities and may help in the early intervention to the cognitive impairment.