Neuroimaging in schizophrenia: what does it tell the clinician?

Is that schizophrenia or frontotemporal dementia? Supporting clinicians in making the right diagnosis

Schizophrenia (SCH) and frontotemporal dementia (FTD) are neurobehavioral syndromes characterized by a profound alteration in personal and social conduct. Differential diagnosis between SCH and FTD remains a challenge. In this short narrative review, we summarize evidences regarding similarities and differences between these disorders to support clinicians in making the right diagnosis. Reports of FTD misdiagnosed as schizophrenia or schizophrenia-like psychosis are frequently reported in the literature. The behavioural variant of FTD (bvFTD) along with familial FTD characterized by delusions and hallucinations represent the medical conditions that best illustrate overlaps between psychiatry and neurology. Neuropsychological patterns of core deficits and anatomical and physiological brain alterations primarily concur in differencing such disorders while additional research on genetic alterations and their reflection on clinical phenotypes should be implemented in the near future. In some cases, a correct diagnosis should be made within an interdisciplinary clinical setting by complementary competences and follow-up visits to evaluate pathology evolution.

Three-dimensional fluorescent microscopy via simultaneous illumination and detection at multiple planes

The conventional optical microscope is an inherently two-dimensional (2D) imaging tool. The objective lens, eyepiece and image sensor are all designed to capture light emitted from a 2D ‘object plane’. Existing technologies, such as confocal or light sheet fluorescence microscopy have to utilize mechanical scanning, a time-multiplexing process, to capture a 3D image. In this paper, we present a 3D optical microscopy method based upon simultaneously illuminating and detecting multiple focal planes. This is implemented by adding two diffractive optical elements to modify the illumination and detection optics. We demonstrate that the image quality of this technique is comparable to conventional light sheet fluorescent microscopy with the advantage of the simultaneous imaging of multiple axial planes and reduced number of scans required to image the whole sample volume.

Retrospective study on structural neuroimaging in first-episode psychosis

Background. No consensus between guidelines exists regarding neuroimaging in first-episode psychosis. The purpose of this study is to assess anomalies found in structural neuroimaging exams (brain computed tomography (CT) and magnetic resonance imaging (MRI)) in the initial medical work-up of patients presenting first-episode psychosis. Methods. The study subjects were 32 patients aged 18-48 years (mean age: 29.6 years), consecutively admitted with first-episode psychosis diagnosis. Socio-demographic and clinical data and neuroimaging exams (CT and MRI) were retrospectively studied. Diagnostic assessments were made using the Operational Criteria Checklist +. Neuroimaging images (CT and MRI) and respective reports were analysed by an experienced consultant psychiatrist. Results. None of the patients had abnormalities in neuroimaging exams responsible for psychotic symptoms. Thirty-seven percent of patients had incidental brain findings not causally related to the psychosis (brain atrophy, arachnoid cyst, asymmetric lateral ventricles, dilated lateral ventricles, plagiocephaly and falx cerebri calcification). No further medical referral was needed for any of these patients. No significant differences regarding gender, age, diagnosis, duration of untreated psychosis, in-stay and cannabis use were found between patients who had neuroimaging abnormalities versus those without. Discussion. This study suggests that structural neuroimaging exams reveal scarce abnormalities in young patients with first-episode psychosis. Structural neuroimaging is especially useful in first-episode psychosis patients with neurological symptoms, atypical clinical picture and old age.

First episode psychosis and an underlying cerebellar tumour

We report on the case of a middle aged lady who was referred by her GP with what appeared to be a case of first episode psychosis. Following assessment and investigation an underlying cerebellar tumour was identified. Our aim is to draw attention to the ongoing debates regarding the possible role of the cerebellum in psychosis and cognition and on neuroimaging as a diagnostic modality in cases of first episode psychosis.

The genomics of schizophrenia: update and implications

Schizophrenia is strongly familial yet rarely (if ever) exhibits classical Mendelian inheritance patterns. The advent of large-scale genotyping and sequencing projects has yielded large data sets with higher statistical power in an effort to uncover new associations with schizophrenia. Here, we review the challenges in dissecting the genetics of schizophrenia and provide an update of the current understanding of the underlying genomics. We discuss the breadth of susceptibility alleles, including those that may occur with low frequency and high disease risk, such as the 22q11.2 hemideletion, as well as alleles that may occur with greater frequency but convey a lower risk of schizophrenia, such as variants in genes encoding subunits of the voltage-gated L-type calcium channel. Finally, we provide an overview of the clinical implications for the diagnosis and treatment of schizophrenia based on progress in understanding the underlying genetic basis.

Exploring the knowledge contained in neuroimages: statistical discriminant analysis and automatic segmentation of the most significant changes

OBJECTIVE

The aim of this article is to propose an integrated framework for extracting and describing patterns of disorders from medical images using a combination of linear discriminant analysis and active contour models.

METHODS

A multivariate statistical methodology was first used to identify the most discriminating hyperplane separating two groups of images (from healthy controls and patients with schizophrenia) contained in the input data. After this, the present work makes explicit the differences found by the multivariate statistical method by subtracting the discriminant models of controls and patients, weighted by the pooled variance between the two groups. A variational level-set technique was used to segment clusters of these differences. We obtain a label of each anatomical change using the Talairach atlas.

RESULTS

In this work all the data was analysed simultaneously rather than assuming a priori regions of interest. As a consequence of this, by using active contour models, we were able to obtain regions of interest that were emergent from the data. The results were evaluated using, as gold standard, well-known facts about the neuroanatomical changes related to schizophrenia. Most of the items in the gold standard was covered in our result set.

CONCLUSIONS

We argue that such investigation provides a suitable framework for characterising the high complexity of magnetic resonance images in schizophrenia as the results obtained indicate a high sensitivity rate with respect to the gold standard.

Is computed tomography still useful as a neuroimaging tool in psychiatry?

BACKGROUND

Computed tomography (CT) has played a pivotal role in psychiatry from its inception; however with the advent of other high-resolution noninvasive neuroimaging techniques such as MRI, the field has gone through a dramatic transformation.

OBJECTIVE

This article will explore the current role of CT in psychiatry.

METHODS

An extensive search of the published literature (1970 - 2008) was conducted, employing a number of databases and terms relevant to CT and imaging.

RESULTS/CONCLUSION

At present CT is primarily used as a screening tool to exclude intracranial pathology. This is partly because it is widely available and less expensive than other imaging modalities. CT is unable to provide region-specific information like MRI and this has restricted its use in disorders in which functional disturbances are suspected, however it remains the preferred mode of investigation where gross structural abnormalities are suspected.

Conceptual issues in psychiatric neuroimaging

PURPOSE OF REVIEW

Psychiatric neuroimaging has made a dramatic impact on the understanding of the brain in mental illness in a relatively brief period of time and continues to be evolving in terms of methodology, analysis and utilization of the combination of techniques. Given the level of sophistication of the techniques and the importance of imaging in current academic psychiatry, it is timely to review its conceptual influence on psychopathology.

RECENT FINDINGS

The study will review scientific advances in psychiatric neuromaging, around the themes of functional connectivity, diffusion tensor imaging, magnetoencephalography, modality integration, meta-analyses and mega-analyses of data and discuss recent influential findings in contemporary research. We then focus on more conceptual issues relating to biological psychiatry and its relationship with cognitive neuroscience. We discuss the dominant paradigm of scientific psychopathology, namely cognitive neuropsychiatry and how it relates more broadly to imaging and cognitive science and elaborate on the philosophical positions of the paradigm and how it views abnormal mental states.

SUMMARY

We conclude that despite the advances in biological psychiatry and the power of the cognitive neuropsychiatry paradigm, its findings are logically contingent upon psychopathology and the normatively defined terms employed therein.