Zhenchang Wang

Gender consistency and difference in healthy adults revealed by cortical thickness

Many previous studies have shown that there exists the gender effect on the structural and functional organization in the human brain. Although the reported functional differences are generally consistent, the structural differences are controversial among the various studies. In this study, we particularly focused on the gender-related effect in the gray matter (GM). We performed a structural magnetic resonance imaging (MRI) study in 184 healthy adults (90 males and 94 females) with ages ranging from 18 to 70 years. Cortical thickness was measured using an automated surface-based method. Based on this surface morphological feature of GM, we first compared their regional differences between males and females. We then constructed the morphometry-based anatomical networks derived from cortical thickness measurement, while the anatomical connection between two cortical areas depended upon the statistical dependence of their cortical thickness across subjects. Subsequently, we applied graph theoretical approaches to investigate the properties of the resultant anatomical networks. The results showed that the significant gender-related differences of cortical thickness appeared extensively in the frontal, parietal and occipital lobes. And there were also some between-group differences in the interregional correlation. Additional graph theoretical analysis on the morphological networks revealed both networks exhibited the small-world efficiency and their patterns of topological vulnerability had no statistical differences. The findings on the large sample may provide the evidences to study the gender consistency and difference in the human brain structures.

Value of MR imaging in the differentiation of benign and malignant orbital tumors in adults

PurposeTo prospectively evaluate magnetic resonance (MR) imaging including dynamic contrast-enhanced MR imaging in the differentiation of benign from malignant orbital masses and to evaluate which MR imaging features are most predictive of malignant tumors.Materials and methodsThe study was approved by the institutional review board and signed informed consent was obtained. Nonenhanced, static, and dynamic contrast-enhanced MR imaging was performed in 102 adult patients with an orbital mass. Diagnosis was based on histologic findings. MR imaging features of benign and malignant orbital lesions were evaluated correlated with histological findings. Multivariate logistic regression analysis was employed to identify the best combination of MR imaging features that might be predictive of malignancy.ResultsNonenhanced, static, and dynamic enhancement MR imaging was significantly superior to two other models in prediction of malignancy (p < 0.05). Multivariate logistic regression analysis identified that the most discriminating MR imaging features were isointense mass on T2-weighted imaging and a washout-type time–intensity curve for both observers.ConclusionNonenhanced, static, and dynamic enhancement MR imaging improved differentiation between benign and malignant orbital masses in adult patients.

Evaluation of MR imaging findings differentiating cavernous haemangiomas from schwannomas in the orbit.

ObjectiveIt is important to distinguish between orbital cavernous haemangioma and schwannoma because the treatments of choice for the two tumours are different. The aim was to evaluate MR imaging findings distinguishing the two tumours.MethodsMagnetic resonance imaging including T1- and T2-weighted imaging and contrast-enhanced MR imaging was performed in 43 patients with cavernous haemangiomas and 16 patients with schwannomas confirmed by pathology. Location, configuration, margins, signal intensity, homogeneity and enhancement pattern of the tumour were retrospectively evaluated.ResultsThere was a significant difference between cavernous haemangiomas and schwannomas regarding the location, configuration and margins of the mass, signal intensity and homogeneity on T1- and T2-weighted imaging, the spread pattern of contrast enhancement, the enhancement pattern and the type of time–intensity curve (P < 0.05). Markedly homogeneous hyperintensity signal on T2-weighted imaging and the spread pattern of the contrast enhancement favoured cavernous haemangioma rather than schwannoma (P < 0.01).ConclusionCavernous haemangiomas and schwannomas have different MR imaging features that could be helpful in the differentiation between the tumours. The spread pattern of the contrast enhancement on dynamic contrast-enhanced MR imaging is the most reliable finding distinguishing cavernous haemangiomas from schwannomas.

Cortical thickness analysis and optimized voxel-based morphometry in children and adolescents with prelingually profound sensorineural hearing loss

Crossmodal neuroplastic changes following auditory deprivation in individuals with profound sensorineural hearing loss (SNHL) have been well documented in previous literature. However, previous studies have shown very little evidence of structural brain changes in individuals with prelingually profound SNHL and no studies have reported significant differences of gray matter (GM) in deaf subjects. Therefore, it is essential to employ a more specific and sensitive technique to detect subtle structural brain differences in deaf individuals. The objective of our study was to investigate neuroanatomical differences in children and adolescents with profound SNHL by cortical thickness analysis and optimized voxel-based morphometry (VBM). T1-weighted volumetric images of 16 children and adolescents with prelingually profound SNHL and 16 hearing controls were analyzed. The ANCOVA analysis revealed a statistically significant decreased average cortical thickness of the whole brain. As to vertex-based analysis, cortical thickness of the deaf subjects showed significant thinning in the left precentral gyrus, right postcentral gyrus, the left superior occipital gyrus and the left fusiform gyrus compared with the hearing subjects. VBM revealed statistically significant focal reduction of white matter (WM) volume in the left middle frontal gyrus and the right inferior occipital gyrus in deaf subjects without statistically significant differences in GM volume between the two groups. These findings demonstrated that structural changes happened not only in the WM but also in the GM of the subjects with prelingually profound SNHL, which have never been reported before in any previous literature. Our results also implicated the potential neuroplastic changes associated with crossmodal reorganization in the brain after auditory deprivation in the early deafness.

Clinical characteristics of pulsatile tinnitus caused by sigmoid sinus diverticulum and wall dehiscence: a study of 54 patients

Abstract Conclusions: CT angiography (CTA) and digital subtraction angiography (DSA) are valuable tools in imaging work-ups for the diagnosis of sigmoid sinus diverticulum (SSD) and sigmoid sinus wall dehiscence (SSWD). The development of pulsatile tinnitus (PT) resulting from SSD and SSWD may be associated with the dominance of venous systems. Objective: Our goal was to evaluate the clinical characteristics of PT caused by SSD and SSWD. Methods: This was a retrospective chart review undertaken in a tertiary academic referral center. Fifty-four patients with PT due to SSD and SSWD were recruited. Hospital files of these patients were assessed. Data included medical history, physical examinations, auxiliary examinations, and radiographic findings of CTA and DSA. Results: The study population comprised 51 females and 3 males. Most patients with PT caused by SSD and SSWD were middle-aged women. All had normal otoscopy results. Anomalies occurred in or adjacent to the region of the transverse–sigmoid sinus junction in 52 patients. Half of the patients (27/54) presented abnormal results of examination of blood lipids. There were 57.41% (31/54) cases with ipsilateral dominance of the venous system, 9.26% (5/54) cases with contralateral dominance, and 33.33% (18/54) cases with co-dominance of the venous system.

Sigmoid sinus diverticulum and pulsatile tinnitus: analysis of CT scans from 15 cases.

Background Although the imaging features of sigmoid sinus diverticulum induced pulsatile tinnitus (PT) have been presented in some extent, detailed imaging findings still have not been systematically evaluated and precise diagnostic radiographic criteria has not been established. Purpose To examine the computed tomography (CT) characteristics of sigmoid sinus diverticulum accompanied with PT. Material and Methods Fifteen PT patients with sigmoid sinus diverticula proven by surgery were recruited after consenting. CT images of 15 patients were obtained and analyzed, including features of diverticula, brain venous systems, integrity of the sigmoid plate, and the degree of temporal bone pneumatization. Results Sigmoid sinus diverticulum was located on the same side of PT in 15 patients. Diverticula originated at the superior curve of the sigmoid sinus in 11 patients and the descending segment of the sigmoid sinus in four patients. Sigmoid sinus diverticula focally eroded into the adjacent mastoid air cells in 12 patients and mastoid cortex in three patients. Among eight patients with unilateral dominant brain venous systems, the diverticula were seen on the dominant side in seven patients and non-dominant side in one patient. In contrast, the other seven patients showed co-dominant brain venous systems, with three presenting diverticula on the right side and four on the left. More notably, dehiscent sigmoid plate on the PT side was demonstrated in all patients. In addition, temporal bone hyper-pneumatization was found in nine patients, good and moderate pneumatization in three patients, respectively. Conclusion Dehiscent sigmoid plate and extensive temporal bone pneumatization are two important imaging characteristics of the PT induced by sigmoid sinus diverticulum.

The Cochlear Nerve Canal and Internal Auditory Canal in Children with Normal Cochlea but Cochlear Nerve Deficiency

Background There is an increasing frequency of requests for cochlear implantation (CI) in deaf children and more detailed image information is necessary for selecting appropriate candidates. Cochlear nerve deficiency (CND) is a contraindication to CI. Magnetic resonance imaging (MRI) has been used to evaluate the integrity of the cochlear nerve. The abnormalities of the cochlear nerve canal (CNC) and internal auditory canal (IAC) have been reported to be associated with CND. Purpose To correlate CNC manifestation, size, and IAC diameter on high-resolution CT (HRCT) with CND diagnosed by MRI in children. Material and Methods HRCT images from 35 sensorineurally deaf children who had normal cochlea but bilateral or unilateral CND diagnosed by MRI were studied retrospectively. The CNC and IAC manifestation and size were assessed and correlated with CND. Results CND was diagnosed by MRI in 54/70 ears (77.1%). Thirty-two ears had an absent cochlear nerve (59.3%), while 22 ears had a small cochlear nerve (40.7%). The CNC diameter was, 1.5 mm in 36 ears (66.7%). The CNC diameter ranged between 1.5 and 2.0 mm in seven ears (13.0%) and was .2.0 mm in 11 ears (20.4%). The IAC diameter was, 3.0 mm in 25 ears (46.3%) and .3.0 mm in 29 ears (53.7%). Conclusion The hypoplastic CNC might be more highly indicative of CND than that of a narrow IAC.

Application of texture analysis based on apparent diffusion coefficient maps in discriminating different stages of rectal cancer

To explore the potential of texture analysis based on apparent diffusion coefficient (ADC) maps, as a predictor of local invasion depth (stage pT1‐2 versus pT3‐4) and nodal status (pN0 versus pN1‐2) of rectal cancer.

Incidence of Vascular Anomalies and Variants Associated with Unilateral Venous Pulsatile Tinnitus in 242 Patients Based on Dual-phase Contrast-enhanced Computed Tomography

Background: A comprehensive assessment of various vascular anomalies and variants associated with venous pulsatile tinnitus (PT) by radiography is essential for therapeutic planning and improving the clinical outcome. This study evaluated the incidence of various vascular anomalies and variants on the PT side and determined whether these lesions occurred as multiple or single entities. Methods: The dual-phase contrast-enhanced computed tomography images of 242 patients with unilateral venous PT were retrospectively reviewed. The vascular anomalies and variants on the symptomatic and asymptomatic sides were analyzed, and the incidences of anomalies or variants on each side were compared. The number of anomalies and variants on the symptomatic side in each patient was calculated. Results: (1) A total 170 patients (170/242) had more than one anomaly or variant on the symptomatic side, and 58 patients (58/242) had a single lesion on tomography. (2) There was a statistically significant difference in the incidence of dehiscent sigmoid plate (P = 0.000), lateral sinus stenosis (P = 0.014), high jugular bulb (P = 0.000), sigmoid sinus diverticulum (P = 0.000), jugular bulb diverticulum (P = 0.000), dehiscent jugular bulb (P = 0.000), and a large emissary vein (P = 0.006) between the symptomatic and asymptomatic sides. (3) Dehiscent sigmoid plate (86.4%) was the most frequent lesion on the symptomatic side, followed by lateral sinus stenosis (55.8%), high jugular bulb (47.1%), sigmoid sinus diverticulum (34.3%), jugular bulb diverticulum (13.6%), dehiscent jugular bulb (13.6%), large emissary vein (4.1%), sinus thrombosis (1.2%), and petrosquamosal sinus (0.8%). Conclusions: Various vascular anomalies and variants occur more frequently on the venous PT side. Preliminary findings suggest that venous PT patients may have multiple vascular anomalies or variants on the symptomatic side.

Alterations of grey matter asymmetries in adolescents with prelingual deafness: a combined VBM and cortical thickness analysis.

PURPOSE Prelingual deafness has been shown to lead to brain reorganization as demonstrated by functional parameters, but anatomical evidences still remain controversial. The present study investigated hemispheric asymmetry changes in deaf subjects using MRI, hypothesizing auditory-, language- or visual-related regions after early deafness. METHODS Prelingually deaf adolescents (n = 16) and age- and gender-matched normal controls (n = 16) were recruited and hemispheric asymmetry was evaluated with voxel-based morphometry (VBM) from MRI combined with analysis of cortical thickness (CTh). RESULTS Deaf adolescents showed more rightward asymmetries (L < R) of grey matter volume (GMV) in the cerebellum and more leftward CTh asymmetries (L > R) in the posterior cingulate gyrus and gyrus rectus. More rightward CTh asymmetries were observed in the precuneus, middle and superior frontal gyri, and middle occipital gyrus. The duration of hearing aid use was correlated with asymmetry of GMV in the cerebellum and CTh in the gyrus rectus. Interestingly, the asymmetry of the auditory cortex was preserved in deaf subjects. CONCLUSIONS When the brain is deprived of auditory input early in life there are signs of both irreversible morphological asymmetry changes in different brain regions but also signs of reorganization and plasticity which are dependent on hearing aid use, i.e. use-dependent.