Altered Topological Properties of Static/Dynamic Functional Networks and Cognitive Function After Radiotherapy for Nasopharyngeal Carcinoma Using Resting-State fMRI.

OBJECTIVES: The purpose of this study was to (1) explore the changes in topological properties of static and dynamic brain functional networks after nasopharyngeal carcinoma (NPC) radiotherapy (RT) using rs-fMRI and graph theoretical analysis, (2) explore the correlation between cognitive function and changes in brain function, and (3) add to the understanding of the pathogenesis of radiation brain injury (RBI). METHODS: Fifty-four patients were divided into 3 groups according to time after RT: PT1 (0-6 months); PT2 (>6 to ≤12 months); and PT3 (>12 months). 29 normal controls (NCs) were included. The subjects' topological properties were evaluated by graph-theoretic network analysis, the functional connectivity of static functional networks was calculated using network-based statistics, and the dynamic functional network matrix was subjected to cluster analysis. Finally, correlation analyses were conducted to explore the relationship between the altered network parameters and cognitive function. RESULTS: Assortativity, hierarchy, and network efficiency were significantly abnormal in the PT1 group compared with the NC or PT3 group. The small-world variance in the PT3 group was smaller than that in NCs. The Nodal ClustCoeff of Postcentral_R in the PT2 group was significantly smaller than that in PT3 and NC groups. Functional connectivities were significantly reduced in the patient groups. Most of the functional connectivities of the middle temporal gyrus (MTG) were shown to be significantly reduced in all three patient groups. Most of the functional connectivities of the insula showed significantly reduced in the PT1 and PT3 groups, and most of the functional connectivities in brain regions such as frontal and parietal lobes showed significantly reduced in the PT2 and PT3 groups. These abnormal functional connectivities were correlated with scores on multiple scales that primarily assessed memory, executive ability, and overall cognitive function. The frequency F of occurrence of various states in each subject differed significantly, and the interaction effect of group and state was significant. CONCLUSION: The disruption of static and dynamic functional network stability, reduced network efficiency and reduced functional connectivity may be potential biomarkers of RBI. Our findings may provide new insights into the pathogenesis of RBI from the perspective of functional networks.

Ultrasound-guided phrenic nerve block for intraoperative persistent hiccups: a case report.

BACKGROUND: Continuous hiccups during surgery not only affect the surgical procedure, they can also cause adverse effects for the patient. Apart from active investigation of the cause of the hiccups, their timely termination is also necessary. CASE PRESENTATION: We reported a case of a 70-year-old woman with continuous intraoperative hiccups that appeared during vaginal hysterectomy under low continuous epidural anesthesia. After the ineffectiveness CO2 repeated inhalation and intravenous administration of chlorpromazine and methoxychlorpromide, we performed unilateral phrenic nerve block under ultrasound guidance. Hiccups were terminated without any related complications. CONCLUSIONS: During intraoperative continuous hiccups, ultrasound guided phrenic nerve block may be a suitable treatment option when physical methods and drug therapy are not effective. However, given the absence of a vital risk related to hiccups, this block should imply the complete absence of any respiratory contraindication and a prolonged postoperative respiratory monitoring.

Whole-brain changes in white matter microstructure after radiotherapy for nasopharyngeal carcinoma: a diffusion tensor imaging study.

Radiation-induced local white matter (WM) damage has been observed by diffusion tensor imaging (DTI) within a priori-defined regions of interest following radiotherapy (RT) for nasopharyngeal carcinoma (NPC). In this study, we aimed to detect WM changes throughout the brain of NPC patients by DTI. Tract-based spatial statistics (TBSS) was used to analyze DTI data from 81 NPC patients. Fractional anisotropy (FA) and mean diffusivity (MD) were quantified across the whole brain in separate groups: pre-RT, and <6, 6-12, and >12 months post-RT. We found that fractional anisotropy values were significantly lower in the right frontal, parietal, and occipital WM <6 months post-RT compared with pre-RT and remained significantly lower in the right frontal and parietal WM at >12 months. MD values were significantly higher in the right occipital, bilateral temporal, right occipital-temporal junction, left parietal, left centrum semiovale, and left frontal-parietal junction WM <6 months post-RT and remained higher in the right occipital WM at >12 months. This study suggests that changes in white matter microstructure following RT for NPC were widespread, complex, and dynamic. Diffusion tensor imaging with TBSS analysis allows for early non-invasive detection of RT-induced WM damage.

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 2011 were 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.