Localized proton and phosphorus magnetic resonance spectroscopy following electroconvulsive therapy

31P RINEPT MRSI and VBM reveal alterations in brain aging associated with major depression

PURPOSE

Phosphomono- and diesters, the major components of the choline peak in (1) H magnetic resonance spectroscopy, are associated with membrane anabolic and catabolic mechanisms. With the refocused insensitive nuclei-enhanced polarization transfer technique, these phospholipids are edited and enhanced in the (31) P MR spectrum. In depressed patients, alterations of the choline peak and cerebral volume have been found, indicating a possible relation. Thus, combining MR phosphorous spectroscopy and volumetry in depressed patients seems to be a promising approach to detect underlying pathomechanisms.

METHODS

Depressed in-patients were either treated with antidepressive medication or with electroconvulsive therapy and compared to matched healthy controls. (31) P magnetic resonance spectroscopy imaging was conducted before and after the treatment phases. A 3D MRI dataset for volumetry was acquired in a dedicated (1) H head coil.

RESULTS

Phosphocholine and phosphoethanolamine were increased in depressed patients. Though patients responded to the treatments, phospholipids were not significantly altered. An increased age-related gray matter loss in fronto-limbic regions along with an altered relation of phosphomonoesters/phosphodiesters with age were found in depressed patients.

DISCUSSION

The findings of increased phosphomonoesthers and an age*group interaction for gray matter volumes need further research to define the role of phospholipids in major depression and possible associations to gray matter loss.

[Adverse cognitive effects and ECT]

Electroconvulsive therapy (ECT) is a rapidly acting and highly effective treatment for severe and life threatening conditions seen in affective and schizophrenic diseases. Notwithstanding its therapeutic benefits, ECT remains controversial because of seizure induction, cognitive side effects, memory dysfunction and effects on cerebral physiology. These factors have raised the concern that ECT produces structural and functional brain damages. This issue continues to have a major impact on the acceptance of ECT as a therapeutic modality, both within the medical community and in public opinion. A close look at incidence, type, severity, neurofunctional and -anatomical correlates, aetiology and therapeutic approaches of the adverse cognitive effects attributed to ECT may contribute to rational and objective handling of this topic. The final chapter deals with the issue of whether ECT causes brain damage.

Structural and functional neuroimaging of electroconvulsive therapy and transcranial magnetic stimulation

Neuroimaging has long been utilized to provide a measure of the effects of electroconvulsive therapy (ECT) on brain structure and function as well as to better understand its mechanisms of action. In a similar fashion, functional neuroimaging may provide the means to elucidate both the underlying neurobiological effects and therapeutic potential of transcranial magnetic stimulation (TMS). This article will review findings of neuroimaging studies of both TMS and ECT, concentrating on how such studies may help guide treatment.

Brain biochemistry using magnetic resonance spectroscopy: relevance to psychiatric illness in the elderly

Magnetic resonance spectroscopy (MRS) allows for the noninvasive study of cerebral biochemistry. It has been used to investigate cerebral metabolic changes associated with mental illness in vivo and in vitro. In this review, we will discuss the application of MRS to psychiatric illness in the elderly. Following a brief description of the basic principles of MRS, the use of phosphorus (31P) and proton (1H) MRS to enable a better understanding of normal brain aging, dementia (Alzheimer's disease, multiple subcortical infarct dementia, Down syndrome, frontotemporal dementia, vascular dementia, age-associated memory impairment, and other dementias), major depression, and electroconvulsive therapy is detailed.

The functional neuroanatomy of mood disorders

Mood disorders may be associated with global and regional changes in cerebral blood flow and metabolism. The accumulated functional neuroimaging findings in mood disorders were reviewed in order to examine a proposed neuroanatomic model of pathophysiology. Global cerebral blood flow and glucose metabolism appear normal, but may be decreased in late-life depression. Regional cerebral blood flow and glucose metabolism deficits are present, and may be indicators of brain regions participating in neuroanatomic circuits involved in mood disorders. Decreased pre-frontal cortex blood flow and metabolism in depressed unipolar and bipolar patients are the most consistently replicated findings, and correlate with severity of illness. Basal ganglia abnormalities have been found in depressed unipolar and bipolar patients, involving decreased blood flow and metabolism. Temporal lobe abnormalities are present in bipolar disorder patients, and perhaps unipolar depression. There is conflicting evidence of abnormalities in other limbic regions. Cognitive impairment may correlate with decreased metabolism in frontal and cerebellar areas. The relationship between functional neuroimaging findings and clinical course, and therefore state and trait characteristics, has not been systematically investigated. Antidepressant medications, but not ECT, seem to reverse some of the identified functional brain changes in the depressed state. The structural, neurotransmitter and neuropathological correlates of these functional abnormalities are yet to be determined. Functional abnormalities in frontal, subcortical and limbic structures appear to be part of the pathophysiology of mood disorders.

Nuclear magnetic resonance spectroscopy: a review of neuropsychiatric applications

1. Magnetic resonance spectroscopy (MRS) is a powerful new neuropsychiatric research tool which allows for the noninvasive investigation of in vivo biochemistry. This review focuses on the recent applications of MRS to in vivo neuropsychiatric research. 2. The history of MRS as it has progressed from an in vitro method of biochemical analysis to its current in vivo research uses is presented. 3. A brief overview of the physical principles of MRS, including methods for spectral localization, is discussed. 4. Applications of the different MRS modalities (1H, 31P, 19F, 7Li, 13C and 23Na) to various neuropsychiatric disorders such as Alzheimer's disease, schizophrenia, affective disorders, acquired immunodeficiency disease, etc. are reviewed. The study of both fluorinated neuroleptics and the antidepressant fluoxetine using 19F MRS are discussed in greater detail. 5. Finally, potential future neuropsychiatric applications of MRS and specifically 19F MRS are presented.