phosphocreatine and AIDS-Dementia-Complex

NONINVASIVE EXPLORATION: Proton localized magnetic resonance spectroscopy (MRS) is a noninvasive human neurochemistry method based on the magnetic resonance phenomenon.. This exploration of brain metabolism, performed without any injection, detects neuronal, glial, and membrane markers, and can be performed after an MRI examination without moving the patient.. In vivo brain MRS plays a major role (i) in early diagnosis of HIV-related encephalopathy, (ii) in differential diagnosis of HIV-related encephalopathy versus psychiatric symptoms or occurring in AIDS patients, (iii) in differential diagnosis of HIV-related encephalopathy versus other brain lesions related to AIDS, and (iv) in the follow-up of patient response to therapy. In these indications, MRS is frequently more reliable than neuropsychologic testing and more sensitive than MRI.

Topics: AIDS Dementia Complex; Aspartic Acid; Brain; Choline; Creatine; Energy Metabolism; Humans; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Phosphocreatine; Reference Values

The aim of this study is to evaluate comparatively the metabolic information afforded by proton magnetic resonance (MR) spectroscopy with stimulated-echo acquisition mode (STEAM) (echo time [TE], 20 mseconds) and point-resolved spectroscopy sequence (PRESS) (TE, 135 mseconds) spectra in HIV-related encephalopathy.. Sixty-three human immunodeficiency virus (HIV) patients and 8 controls were examined by single-voxel proton MR spectroscopy at 1.5 tesla, using both PRESS (TE, 135 mseconds) and STEAM (TE, 20 mseconds) sequences performed during the same MR examination, in the same volume of interest. Cerebral atrophy was quantitated using bicaudate ratio (BCR) and bifrontal ratio (BFR).. With the STEAM (TE, 20 mseconds) spectra, mean N-acetylaspartate (NAA)/choline (Cho) and NAA/creatine and phosphocreatine (Cr-PCr) ratios are reduced in acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) patients but not in neuroasymptomatics. The proportion of inositol signal is increased, that of NAA decreased in ADC patients. NAA/Cho and NAA/ Cr-PCr mean values measured with PRESS (TE, 135 mseconds) spectra are significantly reduced in ADC and neuroasymptomatic patients. Bifrontal ratio only correlates with NAA/Cr-PCr and NAA/Cho measured on the PRESS spectrum. PRESS (TE, 135 mseconds) spectra allow a definition of different metabolic patterns in HIV-related encephalopathy. At last, no correlation has been found between the NAA raw signals measured on the PRESS (TE, 135 mseconds) and STEAM (TE, 20 mseconds) spectra obtained in the same MR examination.. STEAM (TE, 20 mseconds) spectra provide more metabolic information-namely an evaluation of glial-neuronal status-than PRESS (TE, 135 mseconds) spectra, which afford a metabolic classification of the HIV-related encephalopathy. Because both sequences afford a similar diagnostic gain, MR spectroscopy examination probably requires spectrum acquisition with both sequences.

Topics: Adult; Aged; AIDS Dementia Complex; Aspartic Acid; Brain; CD4 Lymphocyte Count; Choline; Creatine; Female; HIV Seropositivity; Humans; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Middle Aged; Phosphocreatine; Protons

We examined the effects of human immunodeficiency virus (HIV) infection and chronic alcohol consumption on cerebral phosphorus metabolites to determine if chronic alcohol abuse is a risk factor for the progression of neurological effects of HIV infection. We studied 15 HIV- alcoholics, 8 HIV- light/nondrinkers, 32 HIV+ alcoholics, and 41 HIV+ light/nondrinking men, with both HIV+ groups having similar CD4 lymphocyte counts. We used localized 31-phosphorus magnetic resonance spectroscopy after magnetic resonance imaging to examine two brain volumes in superior white matter and subcortical gray matter. Chronic alcohol consumption was associated with reduced white matter concentrations of phosphodiester (PDE) and phosphocreatine (PCr). Also in the white matter, acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC) were associated with reduced concentrations of PDE and PCr, compared with both HIV- and clinically asymptomatic HIV+ subjects. Because no alcohol-by-HIV interactions were detected, the effects of HIV infection and alcohol abuse were cumulative. This is reflected in a successive decrease of white matter PDE and PCr concentrations in the order HIV- light/nondrinkers/HIV- alcoholics/HIV+ light/nondrinkers/HIV+ alcoholics. Subcortical gray matter PDE concentrations were lower in ARC/AIDS alcoholics than in HIV- light/nondrinking individuals. These findings suggest altered brain phospholipid metabolites and energy metabolites with alcohol abuse and HIV infection. They demonstrate that the adverse metabolic effects of HIV on the brain are augmented by chronic alcohol abuse.

Topics: Acquired Immunodeficiency Syndrome; Adenosine Triphosphate; Adult; AIDS Dementia Complex; AIDS-Related Complex; Alcoholism; Brain; Brain Mapping; HIV Seropositivity; Humans; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Middle Aged; Organophosphates; Phosphocreatine; Phosphorus

To examine the sensitivity of proton MR spectroscopy for detecting early central nervous system abnormalities in neonates born to human immunodeficiency virus (HIV)-positive mothers.. Asleep, unsedated, and continuously monitored by electrocardiography, 10 newborns, 5 with HIV-positive and 5 with HIV-negative mothers, were studied within the first 10 days of life in a 1.5-T scanner. After T1- and T2-weighted images were obtained, proton spectra were performed using voxels of interest (3.4 cm3) in the deep parietooccipital white matter. Peaks were identified as N-acetyl-aspartate (2.0 ppm), creatine and phosphocreatine (3.0 ppm), choline (3.2 ppm), and inositol (3.5 ppm). Peak areas were used to calculate metabolic ratios: N-acetyl-aspartate to creatine, inositol to creatine, and creatine to choline.. All newborns of HIV-positive mothers had abnormal proton spectra compared with control infants; a nonspecific amino acid peak in the 2.1- to 2.6-ppm area was elevated, broad, and overlapping the N-acetyl-aspartate peak in all the HIV-exposed newborns and in only 1 of the 5 control newborns. The choline-to-creatine ratio was higher in HIV-exposed newborns at 2.3 +/- 0.4 (normal term, 0.9 +/- 0.3), as was the N-acetyl-aspartate-to-creatine ratio at 2.6 +/- 0.9 (for control subjects, 1.2 +/- 0.4). MR images from these brain regions were all considered normal. Because acquired immunodeficiency syndrome develops in only a small fraction of neonates born to HIV-seropositive mothers, the above spectral abnormalities found in all our subjects may result from indirect effects of HIV, such as intrauterine growth retardation.. These findings indicate that proton MR spectroscopy might play an important role in detecting early central nervous system complications in newborns of HIV-seropositive mothers.

Topics: AIDS Dementia Complex; Aspartic Acid; Choline; Diagnosis, Differential; Energy Metabolism; Female; Fetal Growth Retardation; HIV Seropositivity; Humans; Infant, Newborn; Infectious Disease Transmission, Vertical; Inositol; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Occipital Lobe; Parietal Lobe; Phosphocreatine

We have examined 9 healthy volunteers and 63 HIV-patients (16 asymptomatic patients and 47 patients with clinical AIDS-dementia complex, ADC) by magnetic resonance spectroscopy (MRS) and imaging (MRI) on a Siemens Magnetom SP63 (1.5 T). Proton MRS of the brain was performed at 63 MHz using the PRESS sequence (echo time = 135 ms, TR = 1.6 s). Four main results have been found: (1) HIV-related encephalopathy induces significant modifications of brain metabolism analyzed by MRS and the most sensitive metabolic parameter is the N-acetyl-aspartate/Choline ratio, (2) the correlation between MRS and MRI is good in 75% of patients, (3) in 4 of the 16 neuro-asymptomatic patients (i.e. 25%) a metabolic encephalopathy was found while MRI was still normal, and (4) MR spectra describe 3 different pathological metabolic patterns in the brain of HIV patients. Two patterns might correspond to the two entities of HIV-induced lesions i.e. HIV encephalitis and HIV-related progressive leukoencephalopathy.

Topics: AIDS Dementia Complex; Aspartic Acid; Brain; Choline; Creatine; HIV Infections; Humans; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Phosphocreatine

Human immunodeficiency virus (HIV)-infected individuals often demonstrate neuropsychiatric impairment; however, it is unclear how brain metabolism may be altered in such patients. We used in vivo phosphorus 31 magnetic resonance spectroscopy to noninvasively assess brain energy and phospholipid metabolism by measuring brain concentrations of adenosine triphosphate (ATP), phosphocreatine (PCr), and inorganic phosphate (Pi), as well as phospholipid compounds and intracellular pH. In study 1, 17 HIV-seropositive men with varying degrees of neuropsychiatric impairment and six control subjects were studied. Localized spectra were obtained from a heterogeneous 5 x 5 x 5-cm volume of interest (VOI). Patients with HIV infection had a significantly lower ATP/Pi ratio and a trend for a lower PCr/Pi ratio than did the control group. In addition, the ATP/Pi and PCr/Pi ratios were both significantly negatively correlated with overall severity of neuropsychiatric impairment. In study 2, three HIV-seropositive men with neuropsychiatric impairment were compared with 11 HIV-seronegative men. Localized phosphorus 31 magnetic resonance spectra were obtained from two relatively homogeneous VOIs: (1) a predominantly white matter VOI, and (2) a predominantly subcortical gray matter VOI. The three HIV-infected patients demonstrated significantly decreased ATP and PCr concentrations in the white matter VOI. These results suggest that HIV infection of the brain may impair brain cellular oxidative metabolism and that the degree of metabolic compromise may be related to the severity of neuropsychiatric impairment.

Topics: Adenosine Triphosphate; Adult; AIDS Dementia Complex; Brain; Female; HIV Infections; Humans; Hydrogen-Ion Concentration; Intracellular Fluid; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Middle Aged; Nervous System Diseases; Phosphates; Phosphocreatine; Phospholipids

To test whether compromised high-energy phosphate metabolism is implicated in the neurologic impairment of acquired immunodeficiency syndrome dementia complex (ADC), brain phosphate metabolite concentrations and ratios were measured noninvasively in 12 patients with mild to moderate ADC and 29 healthy volunteers by use of localized phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy and proton (hydrogen-1) magnetic resonance (MR) imaging. In patients, brain phosphocreatine (PCr) and nucleoside triphosphate (NTP) concentrations in sections through the centrum semiovale that were seen with NMR spectroscopy were reduced significantly from normal values of 4.92 mmol/kg wet weight +/- .13 (standard error of the mean) and 2.79 mmol/kg +/- .11, respectively, to 3.33 mmol/kg +/- .26 and 1.99 mmol/kg +/- .13 (P less than .0001). The ratios of metabolites detectable with P-31 NMR spectroscopy did not differ significantly from those of control subjects. The magnitude of the PCr and NTP deficits in ADC was not explicable by focal abnormalities or cerebral atrophy quantified in images of the same regions. These results are consistent with the hypothesis of a generalized virus-associated toxic process affecting brain cell function in ADC. Noninvasive measurement of metabolite concentrations with NMR spectroscopy provides new functional information that may help quantify disease progression and response to therapy.

Topics: Adult; AIDS Dementia Complex; Atrophy; Brain; Humans; Magnetic Resonance Spectroscopy; Middle Aged; Nucleotides; Organophosphates; Phosphates; Phosphocreatine