Open Neuroimaging Journal最新文献

Accumulating in vivo and ex vivo evidences show that humans suffering from depression have decreased hippocampal volume and altered spine density. Moreover, physical activity has an antidepressant effect in humans and in animal models, but to what extent physical activity can affect hippocampal volume and spine numbers in a model for depression is not known. In this study we analyzed whether physical activity affects hippocampal volume and spine density by analyzing a rodent genetic model of depression, Flinders Sensitive Line Rats (FSL), with Magnetic Resonance Imaging (MRI) and ex vivo Golgi staining. We found that physical activity in the form of voluntary wheel running during 5 weeks increased hippocampal volume. Moreover, runners also had larger numbers of thin spines in the dentate gyrus. Our findings support that voluntary wheel running, which is antidepressive in FSL rats, is associated with increased hippocampal volume and spine numbers.

Background and purpose: A common perception is that increased on-call workload leads to increased resident mistakes. To test this, we evaluated whether increased imaging volume has led to increased errors by residents.

Materials and methods: A retrospective review was made of all overnight neuroradiology CT exams with a primary resident read from 2006-2010. All studies were over-read by staff neuroradiologists next morning. As the volume is higher on Friday through Sunday nights, weekend studies were examined separately. Discrepancies were classified as either minor or major. "Major" discrepancy was defined as a discrepancy that the staff radiologist felt was significant enough to potentially affect patient care, necessitating a corrected report and phone contact with the ordering physician and documentation. The total number of major discrepancies was recorded by quarter. In addition, the total number of neuroradiology CT studies read overnight on-call was noted.

Results: The mean number of cases per night during the weekday increased from 3.0 in 2006 to 5.2 in 2010 (p<0.001). During the weekend, the mean number of cases per night increased from 5.4 in 2006 to 7.6 in 2010 (p<0.001). Despite this increase, the major discrepancy rate decreased from 2.7% in 2006 to 2.3% in 2010 (p=0.34).

Conclusion: Despite an increase in neuroradiology exam volumes, there continues to be a low major discrepancy rate for primary resident interpretations. While continued surveillance of on-call volumes is crucial to the educational environment, concern of increased major errors should not be used as sole justification to limit autonomy.

Integrated global power from the primary structures that composed the Default Mode Network (DMN) and from a random collection of other structures were measured by sLORETA (standardized low-resolution electromagnetic tomography) for young university volunteers who had completed an inventory that contained a subscale by which egocentricity has been inferred. Subjects who exhibited higher scores for egocentricity displayed significantly more power within the DMN structures relative to comparison areas. This was not observed for individuals whose egocentricity scores were lowest where the power differences between the DMN and comparison structures were not significant statistically. DMN power was greater in the right hemisphere than the left for men but greater in the left hemisphere than the right for women. The results are consistent with our operating metaphor that elevation of power or activity within the DMN is associated with greater affiliation with the self and its cognitive contents.

We describe a case of delusional psychosis that was terminated by neurosurgical removal of a large arachnoid cyst. The patient was suffering his first psychotic episode and had symptoms typical of schizophrenia. The case underscores the importance of considering that an arachnoid cyst can induce psychopathological symptoms, even those of schizophrenia. Indeed, such symptoms may be the cyst's only clinical manifestation. In addition, the case highlights the importance of doing a structural imaging test when confronted with a first episode of psychosis, especially if the episode is relatively late in appearance. Such imaging may lead to a diagnosis that in turn can enable a definitive neurosurgical resolution of the psychosis.

We report a case of a benign notochordal cell tumor (BNCT) of the sacrum with atypical imaging features, which was incidentally discovered in a 74-year-old man undergoing evaluation for progressively worsening hip and back pain. It is important for radiologists, pathologists and orthopedic surgeons to be aware of the diagnosis of BNCT and be familiar with its radiographic features to avoid unnecessary treatment. This case illustrates the advantage of percutaneous computed tomography (CT)-guided biopsy as a minimally invasive technique for definitive diagnosis of a BNCT with atypical imaging features.

Finding a path between locations is a routine task in daily life. Mental navigation is often used to plan a route to a destination that is not visible from the current location. We first used functional magnetic resonance imaging (fMRI) and surface-based averaging methods to find high-level brain regions involved in imagined navigation between locations in a building very familiar to each participant. This revealed a mental navigation network that includes the precuneus, retrosplenial cortex (RSC), parahippocampal place area (PPA), occipital place area (OPA), supplementary motor area (SMA), premotor cortex, and areas along the medial and anterior intraparietal sulcus. We then visualized retinotopic maps in the entire cortex using wide-field, natural scene stimuli in a separate set of fMRI experiments. This revealed five distinct visual streams or 'fingers' that extend anteriorly into middle temporal, superior parietal, medial parietal, retrosplenial and ventral occipitotemporal cortex. By using spherical morphing to overlap these two data sets, we showed that the mental navigation network primarily occupies areas that also contain retinotopic maps. Specifically, scene-selective regions RSC, PPA and OPA have a common emphasis on the far periphery of the upper visual field. These results suggest that bottom-up retinotopic organization may help to efficiently encode scene and location information in an eye-centered reference frame for top-down, internally generated mental navigation. This study pushes the border of visual cortex further anterior than was initially expected.

Langerhans cell histiocytosis (LCH) is a rare histiocytic disorder with an unpredictable clinical course and highly varied clinical presentation ranging from single system to multisystem involvement. Although head and neck involvement is common in LCH, isolated bilateral temporal bone involvement is exceedingly rare. Furthermore, LCH is commonly misinterpreted as mastoiditis, otitis media and otitis externa, delaying diagnosis and appropriate therapeutic management. To improve detection and time to treatment, it is imperative to have LCH in the differential diagnosis for unusual presentations of the aforementioned infectious head and neck etiologies. Any lytic lesion of the temporal bone identified by radiology should raise suspicion for LCH. We hereby describe the radiologic findings of a case of bilateral temporal bone LCH, originally misdiagnosed as mastoiditis.

Background: Brain tumours that are associated with cerebral aneurysms are rare occurrences, whereas the coexistence of brain tumours and intra-tumoural aneurysms is even rarer. There have been 12 brain tumour cases that have been reported in the literature that describe an aneurysm within a brain tumour, with 4 of these tumours being meningiomas.

Case description: A 34-year-old male patient presented with sudden-onset headache, and an inter-hemispheric meningioma with intra-tumoural bleeding was found due to a ruptured embedded anterior cerebral artery aneurysm. The aneurysm was diagnosed incidentally on the third cerebral angiogram, while the initial 2 angiograms were negative. The patient was treated with endovascular aneurysm embolisation that was followed by tumour resection.

Conclusion: This paper is the first case report to describe the coexistence of a meningioma and an aneurysm, which presented with intra-tumoural haemorrhage that was negative on the initial cerebral angiogram. Unlike previous case reports, the aneurysm in this case was located with an anterior cerebral artery distribution.