Value Of Magnetic Resonance Spectroscopy Research Articles

Feasibility of 1H-MR Spectroscopy in evaluation of cervical spondylotic myelopathy

PurposeTo assess the diagnostic value of magnetic resonance spectroscopy (MRS) in the evaluation of cervical spinal cord biochemical changes in patients with cervical spondylotic myelopathy (CSM). Materials and methodsTwenty-four patients with cervical spondylotic myelopathy (patient group) and eleven age matched neurologically free volunteers (control group) underwent magnetic resonance imaging. MRS was assessed for the main metabolites including N-acetylaspartate (NAA), Choline (Cho), Creatine (Cr) and Lactate (Lac). The MRS findings of both groups were compared. ResultsSignificant reduction in NAA/Cr ratio of patients with CSM (mean=1.34±0.09) in comparison to controls (mean=1.82±0.08). No significant differences in Cho/Cr ratio between both groups. Lactate peak was detected in nine patients while it was not detected in any of the controls. The difference in NAA/Cr ratio between patients with Lac peak and those without Lac peak was insignificant. ConclusionMRS is a promising non invasive technique that can help to evaluate metabolic changes of the cervical cord in cervical spondylotic myelopathy even in normally looking-areas.

Linking cerebral metabolic function to stress vulnerability (Commentary on Knapman et al.)

Stress is linked to a wide variety of psychological and somatic ailments, including affective diseases (such as depression) and post-traumatic stress disorder. In recent years it has become increasingly clear that the impact of stress on pathology varies substantially from individual to individual (McEwen & Stellar, 1993; Radley et al., 2011). Defining mechanisms underlying individual differences is crucial to understanding the biological basis of stress control and using this knowledge to develop treatment strategies for stress-related diseases. This issue of European Journal of Neuroscience, Knapman et al. (2012) use state-of-the-art imaging methods and proteomics to explore neural events associated with differential stress reactivity in strains of mice selected for low, intermediate and high stress reactivity, as defined by the magnitude of corticosteroid responses to acute stressors. The strain with the greatest corticosterone reactivity to stress has memory deficits that are accompanied by lateralized reductions in hippocampal N-acetyl aspartate (NAA), reduced basal activity in the hippocampus and alterations in expression of hippocampal proteins regulating cellular energy metabolism. The data indicate a novel connection between susceptibility to stress and hippocampal (and perhaps cortical) metabolic function, suggesting mitochondrial dysfunction as a possible mechanism for stress vulnerability and, by extension, stressrelated disease processes. It is generally recognized that animal models of psychiatric disorders are problematic. The (always limited) validity of a model will depend on how well it matches the human disorder. For psychiatric disorders, features related to brain structure, metabolism and function will obviously be of primary relevance and interest. Beyond the implications for individual differences, this work demonstrates the power of advanced magnetic resonance techniques to probe in vivo metabolism and neuronal activity. NAA is now generally accepted as a relatively non-specific marker of neuronal integrity and mitochondrial metabolism (de Graaf, 2007). The value of magnetic resonance spectroscopy (MRS) lies in its ability to measure NAA (and several other major metabolites not probed in the present work) non-invasively and longitudinally in brain in both humans and animal models under a variety of parallel diagnostic criteria and treatment conditions. Longitudinal measures are of particular relevance for mechanistic approaches in animals, where one can achieve ‘before and after’ measurements associated with experimental interventions or genetic manipulations. Moreover, metabolic and functional measures may become clinically relevant at the early stages of a neurochemical disorder, before volume changes in the brain are apparent. Beyond MRS, manganese-enhanced magnetic resonance imaging, although not likely to be applicable to human studies, is becoming a useful adjunct to anatomical magnetic resonance imaging (Inoue et al., 2011) that can provide a crude but unique measure of the functional status of neuronal pathways. Studies like that of Knapman et al. (2012) can bridge the gap between detailed biochemical ⁄ proteomic analysis in animal models and dynamic functional ⁄metabolic measures in the human brain.

Multimodal Imaging in Diagnosis of Alzheimer's Disease and Amnestic Mild Cognitive Impairment: Value of Magnetic Resonance Spectroscopy, Perfusion, and Diffusion Tensor Imaging of the Posterior Cingulate Region

The purpose of this study was to assess metabolic, perfusion, and microstructural changes within the posterior cingulate area in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) using advanced MR techniques such as: spectroscopy (MRS), perfusion weighted imaging (PWI), and diffusion tensor imaging (DTI). Thirty patients with AD (mean age 71.5 y, MMSE 18), 23 with aMCI (mean age 66 y, MMSE 27.4), and 15 age-matched normal controls (mean age 69 y, MMSE 29.5) underwent conventional MRI followed by MRS, PWI, and DTI on 1.5 Tesla MR unit. Several metabolite ratios (N-acetylaspartate [NAA]/creatine [Cr], choline [Ch]/Cr, myoinositol [mI]/Cr, mI/NAA, mI/Cho) as well as parameters of cerebral blood volume relative to cerebellum and fractional anisotropy were obtained in the posterior cingulate region. The above parameters were correlated with the results of neuropsychological tests. AD patients showed significant abnormalities in all evaluated parameters while subjects with aMCI showed only perfusion and diffusion changes in the posterior cingulate area. Only PWI and DTI measurements revealed significant differences among the three evaluated subject groups. DTI, PWI, and MRS results showed significant correlations with neuropsychological tests. DTI changes correlated with both PWI and MRS abnormalities. Of neuroimaging methods, DTI revealed the highest accuracy in diagnosis of AD and aMCI (0.95, 0.79) followed by PWI (0.87, 0.67) and MRS (0.82, 0.47), respectively. In conclusion, AD is a complex pathology regarding both grey and white matter. DTI seems to be the most useful imaging modality to distinguish between AD, aMCI, and control group, followed by PWI and MRS.

N-Acetylcysteine Normalizes Neurochemical Changes in the Glutathione-Deficient Schizophrenia Mouse Model During Development

Glutathione (GSH) is the major cellular redox-regulator and antioxidant. Redox-imbalance due to genetically impaired GSH synthesis is among the risk factors for schizophrenia. Here we used a mouse model with chronic GSH deficit induced by knockout (KO) of the key GSH-synthesizing enzyme, glutamate-cysteine ligase modulatory subunit (GCLM). With high-resolution magnetic resonance spectroscopy at 14.1 T, we determined the neurochemical profile of GCLM-KO, heterozygous, and wild-type mice in anterior cortex throughout development in a longitudinal study design. Chronic GSH deficit was accompanied by an elevation of glutamine (Gln), glutamate (Glu), Gln/Glu, N-acetylaspartate, myo-Inositol, lactate, and alanine. Changes were predominantly present at prepubertal ages (postnatal days 20 and 30). Treatment with N-acetylcysteine from gestation on normalized most neurochemical alterations to wild-type level. Changes observed in GCLM-KO anterior cortex, notably the increase in Gln, Glu, and Gln/Glu, were similar to those reported in early schizophrenia, emphasizing the link between redox imbalance and the disease and validating the model. The data also highlight the prepubertal period as a sensitive time for redox-related neurochemical changes and demonstrate beneficial effects of early N-acetylcysteine treatment. Moreover, the data demonstrate the translational value of magnetic resonance spectroscopy to study brain disease in preclinical models.

Abstract 4070: Treatment with the MEK inhibitor U0126 induces increased lactate production in prostate and breast cancer cell lines

Abstract Introduction. In this study we investigated the metabolic consequences of U0126, a highly selective MEK1/2 inhibitor, in human prostate and breast cancer cell lines using 1H and 13C magnetic resonance spectroscopy (MRS) and gene expression data. Methods. Prostate (PC3 and LNCaP) and breast (MCF7) human cancer cells were treated for 48 h with the IC50 dose of U0126. 1H MRS data were acquired from cell extracts and repeated univariate statistical testing with false discovery rate correction was performed to determine significant changes in metabolite levels. The rate of glycolysis was determined from dynamic studies in live cells using 13C MRS to monitor the metabolism of 1-13C-labeled glucose. Protein and gene expression levels were measured using Western blotting and microarray analysis. Results and Discussion. The effect of U0126 was confirmed by western blot analysis demonstrating a drop in p-ERK. The univariate statistical analysis revealed that the 48 h drug treatment induced several metabolic changes including depletion of intracellular aspartate, succinate and phosphocholine in the prostate cells. However, one of the most significant metabolic change in all three cell lines was a substantial increase in intracellular lactate levels following treatment, with lactate up 134±16% (p=0.002), 149±20% (p=0.001) and 213±43% (n=2) of control in PC3, LNCaP and MCF7 cells respectively. Dynamic studies in live MCF7 cells were in line with the extract data and showed that the rate of lactate production increased following treatment 169±43% from 260±98 fmol/cell/hour to 439±114 fmol/cell/hour (p=0.03). Preliminary studies in PC3 cells showed a similar trend. Consistent with the metabolic observations, overexpression of genes associated with glycolysis including PFKFB3, PDK1, HK2, and GLUT1 was observed in PC3 cells pointing to an increase in glycolytic enzymes induced by U0126 treatment. In an effort to explain this observation we assessed the expression of other signaling proteins and found that although U0126 inhibits its target kinase, increased Akt phosphorylation was also observed in the PC3 cells. Importantly Akt activation was previously reported to mediate an increase in glycolysis. We therefore hypothesize that the observed increases in lactate production and its intracellular accumulation following inhibition of MAPK kinase signaling result from activation of the PI3K/Akt pathway observed in our cells. Conclusion. Deregulation of the MAPK pathway is often involved in oncogenesis, and therefore inhibitors of the pathway are being investigated as targeted cancer therapeutics. Our results highlight the value of MRS in identifying metabolic consequences of treatment that may inform on molecular drug action. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4070. doi:10.1158/1538-7445.AM2011-4070

Spinal cord metabolism and muscle water diffusion in whiplash

Case series. To quantify spinal cord metabolites and neck muscle fast and slow water diffusion in a small sample of patients with chronic whiplash and healthy controls. Brisbane, Queensland, Australia. In five subjects with chronic whiplash and seven controls, we performed magnetic resonance spectroscopy (MRS) of the cervical spinal cord and diffusion-weighted imaging (DWI) of the cervical multifidus muscle. Significant reductions in N-acetylaspartate/creatine ratios were found in subjects with chronic whiplash when compared with healthy controls (P = 0.02). Significantly higher fast apparent diffusion coefficients (ADCs) were found in chronic whiplash when compared with the healthy controls (P = 0.01). There was no difference in slow ADCs between the two groups (P = 0.3). The potential value of MRS and DWI to quantify the presence of neuromuscular degeneration as a potential mechanism underlying chronic whiplash is recognized. Larger-scaled prospective studies are warranted and required.

Preoperative assessment using multimodal functional magnetic resonance imaging techniques in patients with brain gliomas

To evaluate the value of magnetic resonance spectroscopy (MRS), blood oxygen level-dependent imaging (BOLD) and diffusion tensor imaging (DTI) for preoperative assessment in patients with brain gliomas. Twenty-three consecutive glioma patients underwent MRS, BOLD and DTI before operation. The characteristics of images were analysed according to histopathological results. There is significant elevation of the choline (Cho) /creatine (Cr) ratio, Cho peak and depression of the N-acetylaspartate (NAA) peak in gliomas. Elevation of the Cho/Cr, Cho/NAA ratio and the presence of a lipids peak, were consistent with high-grade malignancy. A motor activation scan was achieved by using a motor task paradigm in 20 patients. Deformation and displacement of the motor activations was found in 5 cases. The margin of tumor and peritumoural white matter tracts were identified using apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps. Three patterns of white matter tracts alteration were identified: displacement, infiltration, and disruption. In all 23 patients, the tumors were completely resected in 6 patients, subtotal resected in 8 patients, partial resected in 9 patients. No secondary neurological deficit was occurred in all patients after operation. The combination of MRS, BOLD, and DTI techniques allows appropriate presurgical planning of brain gliomas.

In Vivo Lipid Profiling Using Proton Magnetic Resonance Spectroscopy in an Experimental Liver Fibrosis Model

The aim of this study was to characterize early hepatic lipid changes in an experimental model of liver fibrosis using proton ((1)H) magnetic resonance spectroscopy (MRS) at high magnetic field in vivo. Liver fibrosis was induced in 12 Sprague-Dawley rats by twice-weekly carbon tetrachloride (CCl(4)) administration up to 4 weeks. Eight normal rats were used as controls. Single-voxel (1)H MRS experiments were performed at 7 Tesla to measure signal integrals of various lipid peaks including -CH(3), (-CH(2)-)(n), -CH(2)-C=C-CH(2)-, =C-CH(2)-C= and -CH=CH- at 0.9, 1.3, 2.0, 2.8, and 5.3 ppm, respectively, and peak from choline-containing compounds (CCC) at 3.2 ppm. Total lipid, total saturated fatty acid, total unsaturated fatty acid, total unsaturated bond, polyunsaturated bond, and CCC indices were quantified. Significant increases (P < .01) in total lipid and total saturated fatty acid indices were found in animals with CCl(4)-induced fibrosis as compared with normal animals. In addition, total unsaturated bond and polyunsaturated bond indices of animals at 4 weeks after CCl(4) insult were significantly higher than (P < .01 and P < .05, respectively) those of normal animals and animals at 2 weeks following insult; whereas there was only significant increase (P < .01) in total unsaturated fatty acid index in animals with 4-week CCl(4) insult as compared with normal animals. The hepatic lipid changes in CCl(4)-induced experimental fibrosis model were documented in vivo and longitudinally using (1)HMRSat 7 Tesla. The experimental findings suggested that total saturated fatty acid increase contributed mainly to the total lipid increase in animals with CCl(4) insult. This study also demonstrated the potential value of high field MRS to resolve lipid composition and alterations in liver fibrosis.

Magnetic resonance spectroscopy on hepatocellular carcinoma after transcatheter arterial chemoembolization

Proton magnetic resonance spectroscopy (MRS) of the liver in vivo is in experimental phase. MRS observation on liver cancer after transcatheter arterial chemoembolization (TACE) has seldom been reported. This study was to investigate the value of MRS in assessing the metabolic changes of hepatocellular carcinoma (HCC) after TACE. Twenty-five consecutive patients with pathologically-confirmed HCC received 1H MRS of all hepatic lesions using 1.5T whole body MR scanner before TACE and at 3-10 days after TACE. Choline-to-lipid (Cho/Lip), glucogen/glucose-to-lipid (Glu/Lip), and glytamine/glutamate-to-lipid (Glx/Lip) ratios were measured and analyzed statistically. The Cho/Lip, Glu/Lip, and Glx/Lip ratios were 0.21 +/- 0.08, 0.11 +/- 0.05, 0.28 +/- 0.10 before TACE, respectively, and were 0.10 +/- 0.08, 0.07 +/- 0.07, 0.18 +/- 0.12 after TACE, respectively, with significant differences (P < 0.05). Using MRS can evaluate the early metabolic responses of HCC to TACE.

Relative value of magnetic resonance spectroscopy, magnetic resonance perfusion, and 2-( 18F) fluoro-2-deoxy-D-glucose positron emission tomography for detection of recurrence or grade increase in gliomas

In a consecutive series of 26 previously operated patients diagnosed with cerebral glioma, magnetic resonance spectroscopy (MRS), 2-( 18F) fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), and perfusion MRI (MRP), were performed at follow-up to distinguish recurrence from radiation necrosis, and to identify tumour upgrading. Discrepancy between techniques was observed in 9 cases. The positive predictive value (PPV) and the negative predictive value (NPV) of each technique to detect the presence of high grade glioma was: MRI, PPV = 50%; MRS, PPV = 91.6%, NPV = 100%; FDG-PET, PPV = 75%, NPV = 61.1%; MRP, PPV = 100%, NPV = 100%. In the selected group of nine cases studied to differentiate viable tumour from radiation necrosis, MRS and MRP reached a PPV and a NPV of 100%, whereas for FDG-PET, PPV and NPV were 66.6% and 60%, respectively. To distinguish between viable high-grade glioma and radiation necrosis, gadolinium-enhanced MRI gives a high false-positive rate, while MRS and MRP are superior to FDG-PET in discriminating tumour recurrence, grade increase and radiation necrosis.

Value of magnetic resonance spectroscopy (MSR) and dynamic contrast-enhanced magnetic resonance (DCEMR) imaging for the characterization of high-grade prostatic intraepithelial neoplasia (HGPIN) foci

Background Despite an increasing interest in high-grade prostatic intraepithelial neoplasia (HGPIN), the clinical suspicious aspect of this premalignant lesion remains poorly characterized. The aim of this study was to analyze the magnetic resonance spectroscopy (MSR) and dynamic contrast-enhanced magnetic resonance (DCEMR) imaging features of isolated HGPIN lesions. Materials and methods From January 2007 to January 2009, 330 cases were included in a protocol that involve the use of MSR and DCEMR for the diagnosis of prostate diseases. Of these, 27 patients with isolated (no associated prostate cancer diagnosis) HGPIN histologic diagnosis at the first prostate biopsy were included in the present study. All cases were previously submitted to MSR/DCEMR (1.5 T scanner) and, no later than 10 days to a random 12-core biopsy scheme. Biopsy targeting was done in zones corresponding to those analyzed with MSR and DCEMR. Results In the 27 patients, 30 HGPIN foci with a diameter of 6 mm or greater were analyzed and compared with 27 peripheral zone areas of normal prostate tissue. With MSR, HGPIN foci were characterized by a significantly higher ( P < 0.05) absolute value of choline and choline + creatine/citrate ratio compared with normal tissue. With DCEMR, HGPIN foci were characterized by lower values of all dynamic parameters but differences did not reach statistical significance ( P > 0.05). Conclusions In our experience, HGPIN lesions can be metabolically characterized by MSR through the absolute value of choline and the choline + creatine/citrate ratio.

The value of magnetic resonance spectroscopy in tumour imaging

Magnetic resonance (MR) imaging has a key role in the management of many childhood tumours. There is increasing interest in extending these investigations to MR techniques that give information on...

Value of endorectal MRI and MRS in patients with elevated prostate-specific antigen levels and previous negative biopsies to localize peripheral zone tumours

To evaluate prospectively the role of endorectal magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) in detecting peripheral zone tumour in patients with total prostate-specific antigen (PSA) values>or=4 ng/ml and one or more negative transrectal ultrasound (TRUS) biopsy rounds. Fifty-four consecutive men (mean age 65.4+/-5.2 years, mean total PSA 10.8+/-7.5 ng/ml), underwent a combined MRI-MRS examination with endorectal coil. MRI included transverse, coronal, and sagittal T2-weighted and transverse T1-weighted fast spin-echo sequences. MRS data were acquired using a double spin-echo point resolved spectroscopy (PRESS) sequence. A 10-site scheme was adopted to evaluate the prostate peripheral zone. A peripheral prostatic site was classified as suspicious if low intensity signal was present on T2-weighted images and/or if the choline+creatine/citrate ratio was >0.86. Following MRI-MRS all patients were submitted to a standard 10-core biopsy scheme to which from one to three supplementary samples were added from suspicious MRI and/or MRS sites. In per-patient analysis findings were considered true-positive if biopsy positive patients were classified as suspicious, irrespectively of lesion site indication. Prostate cancer (PC) was detected in 17 of 54 patients (31.5%); median Gleason score was 6 (range 4-8). On a per-patient basis sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were respectively 100, 64.9, 56.7, 100, and 75.9% for MRI; 82.2, 70.3, 57.7, 92.9, and 75.9% for MRS; and 100, 51.4, 48.6, 100, and 66.7% for combined MRI-MRS. In all the 17 PC patients, combined MRI-MRS correctly indicated the sites harbouring cancer, whereas both MRI and MRS gave erroneous indications in two patients. The results of the present study show that MRI alone might be able to select negative patients in whom further biopsies are unnecessary. The combination of MRI and MRS might be able to drive biopsies in suspicious sites and increase the cancer detection rate. Further studies are required to confirm these data.

Apport pronostique de la résonance magnétique cérébrale dans l’encéphalopathie hypoxique-ischémique du nouveau-né à terme : score d’imagerie, spectroscopie. Étude de 26 cas

Neonatal hypoxic-ischemic encephalopathy remains a major cause of chronic disability in childhood. Early diagnosis and prognosis are necessary for the clinician to adapt the treatment. However, there is yet no reliable test to predict the patient's evolution.The aim of our study was to evaluate the predictive value of a personal magnetic resonance imaging (MRI) scoring system and of magnetic resonance spectroscopy (MRS).We included 26 term newborns in condition of neonatal brain suffering. MR examination was performed during the first week of life for all patients and MRI and MRS data were collected. Standardised follow-up visits were made for all patients. Finally, prognostic value of the different criteria was evaluated with statistical tests.Our MRI scoring system proved to be linked to prognosis. A high MRI score, abnormal signal in the internal capsule, white matter or basal ganglia abnormalities with diffusion imaging were associated with unfavourable outcome. These results confirmed the data of the literature concerning the MRI predictive value. Our study also confirmed prognostic interest of MR: particularly, ratios using lactate were significantly linked to prognosis in our study. Specificity of the elevation of these ratios was interesting but sensibility was less optimal.We suggest using our MRI scoring system which associates standard MRI and diffusion imaging, which is significantly related to outcome. We confirm the prognostic value of MRS in this pathological situation. MR with diffusion sequence and spectroscopy, performed three to four days after birth appears to be an essential tool to manage these patients.

Early Morphologic and Spectroscopic Magnetic Resonance in Severe Traumatic Brain Injuries Can Detect “Invisible Brain Stem Damage” and Predict “Vegetative States”

A precise evaluation of the brain damage in the first days of severe traumatic brain injured (TBI) patients is still uncertain despite numerous available cerebral evaluation methods and imaging. In 5-10% of severe TBI patients, clinicians remain concerned with prolonged coma and long-term marked cognitive impairment unexplained by normal morphological T2 star, flair, and diffusion magnetic resonance imaging (MRI). For this reason, we prospectively assessed the potential value of magnetic resonance spectroscopy (MRS) of the brain stem to evaluate the functionality of the consciousness areas. Forty consecutive patients with severe TBI were included. Single voxel proton MRS of the brain stem and morphological MRI of the whole brain were performed at day 17.5 +/- 6.4. Disability Rating Scale and Glasgow Outcome Scale (GOS) were evaluated at 18 months posttrauma. MRS appeared to be a reliable tool in the exploration of brainstem metabolism in TBI. Three different spectra were observed (normal, cholinergic reaction, or neuronal damage) allowing an evaluation of functional damage. MRS disturbances were not correlated with anatomical MRI lesions suggesting that the two techniques are strongly complementarity. In two GOS 2 vegetative patients with normal morphological MRI, MRS detected severe functional damage of the brainstem (NAA/Cr < 1.50) that was described as "invisible brain stem damage." MRI and MRS taken separately could not distinguish patients GOS 3 (n = 7) from GOS 1-2 (n = 11) and GOS 4-5 (n = 20). However, a principal component analysis of combined MRI and MRS data enabled a clear-cut separation between GOS 1-2, GOS 3, and GOS 4-5 patients with no overlap between groups. This study showed that combined MRI and MRS provide a reliable evaluation of patients presenting in deep coma, specially when there are insufficient MRI lesions of the consciousness pathways to explain their status. In the first few days post-trauma metabolic (brainstem spectroscopy) and morphological (T2 star and Flair) MRI studies can predict the long-term neurological outcome, especially the persistent vegetative states and minimally conscious state.

Poster 23: Predictive Value of Magnetic Resonance Spectroscopy for Inpatient Rehabilitation Outcomes Following Traumatic Brain Injury.

Objective: To determine the value of magnetic resonance spectroscopy (MRS) in predicting inpatient rehabilitation outcomes following traumatic brain injury (TBI). Design: Correlation of neurometabolite concentrations with inpatient rehabilitation outcomes. Setting: Tertiary care center. Participants: MRS of 25 patients with TBI ages 16 to 54 (mean, 29) and Glasgow Coma Scale (GCS) scores 3 to 15 (mean, 6). Inclusion criteria included GCS score <13, positive computed tomography or magnetic resonance imaging findings, or positive loss of consciousness.

Magnetic resonance spectral analysis of ovarian teratomas

Mature cystic teratomas are relatively common ovarian neoplasms that usually contain mature tissues of ectodermal mesodermal or endodermal origin. The presence in the pelvis of a detached and freely mobile ovarian teratoma is rare and often diagnosed incidentally. Following complete ovarian torsion and therefore interruption of its arterial blood supply the tumor undergoes atrophy necrosis and autoamputation. Magnetic resonance spectroscopy (MRS) utilizes the same hardware as magnetic resonance imaging (MRI) but it provides information about the biochemical metabolism of living cells. It is used to measure protoncontaining compounds such as amino acids organic acids and sugars in tissue specimens. There have been few reports of MRS use to evaluate ovarian teratomas. Two cases of ovarian teratoma of which one was a mobile calcified intrapelvic mass (the result of autoamputation) are presented and the value of MRS for ovarian teratoma is discussed. To our knowledge this is the first report of MRS use to assess an autoamputated ovarian teratoma. (excerpt)

Cardiac magnetic resonance spectroscopy.

This review describes recent advances in cardiac magnetic resonance spectroscopy (MRS). MRS allows noninvasive characterization of the metabolic state of cardiac muscle, in both animal and human models. Recent experimental MRS studies have allowed new insights into the essential role of energetics in heart failure. Various new studies suggest a rapidly growing role of MRS for phenotyping new genetically modified mouse models, and recent methodologic advances include development of absolute quantification of high-energy phosphates, measurement of ATP turnover rates and thermodynamic parameters (such as free ADP and free energy change of ATP hydrolysis), and improved acquisition sequences. New patient studies demonstrate the potential value of MRS as a clinical diagnostic tool in patients with ischemic heart disease, heart failure, cardiac transplantation, valve disease, and genetic cardiomyopathy.

Correlates of executive function in multiple sclerosis: the use of magnetic resonance spectroscopy as an index of focal pathology.

Proton magnetic resonance spectroscopy (MRS) was performed in a group of patients with multiple sclerosis (MS) and matched control subjects to examine the relationship between frontal lobe pathology and performance on tests of executive function. The N-acetyl aspartate/creatine ratio (NAA/Cr) was significantly reduced in frontal lesions and/or normal-appearing white matter in the patient group compared with the control group, but choline/creatine ratios did not differ. Although MRS abnormalities and executive deficits were not correlated for MS patients as a group, a few patients with more severe abnormalities of NAA/Cr ratio performed worse than other patients on the spatial working memory test, suggesting that subtle frontal neuropathological abnormalities detected by MRS may contribute to executive deficits. Further investigation is warranted to determine the value of MRS as an index of the pathophysiological processes leading to cognitive deficit.

Evidence from proton magnetic resonance spectroscopy for a metabolic cascade of neuronal damage in shaken baby syndrome.

The purpose of this study was to use proton magnetic resonance spectroscopy (MRS) as a metabolic assay to describe biochemical changes during the evolution of neuronal injury in infants after shaken baby syndrome (SBS), that explain the disparity between apparent physical injury and the neurological deficit after SBS. Three infants [6 months (A), 5 weeks (B), 7 months (C)] with SBS were examined repeatedly using localized quantitative proton MRS. Examinations were performed on days 7 and 13 (A), on days 1, 3, 5, and 12 (B), and on days 7 and 19 (C) posttrauma. Long-term follow-up examinations were performed 5 months posttrauma (A) and 4.6 months posttrauma (B). Data were compared to control data from 52 neurologically normal infants presented in a previous study. Spectra from parietal white matter obtained at approximately the same time after injury (5 to 7 days) showed markedly different patterns of abnormality. Infant A shows near normal levels of the neuronal marker N-acetyl aspartate, creatine, and phosphocreatine, although infant C shows absent N-acetyl aspartate, almost absent creatine and phosphocreatine, and a great excess of lactate/lipid and lipid. Analysis of the time course in infant B appears to connect these variations as markers of the severity of head injury suffered in the abuse, indicating a progression of biochemical abnormality. The principal cerebral metabolites detected by MRS that remain normal up to 24 hours fall precipitately to approximately 40% of normal within 5 to 12 days, with lactate/lipid and lipid levels more than doubling concentration between days 5 and 12. A strong impression is gained of MRS as a prognostic marker because infant A recovered although infants B and C remained in a state consistent with compromised neurological capacity. Loss of integrity of the proton MR spectrum appears to signal irreversible neurological damage and occurs at a time when clinical and neurological status gives no indication of long-term outcome. These results suggest the value of sequential MRS in the management of SBS.