Magnetic resonance imaging and 31P magnetic resonance spectroscopy for evaluating focal cerebral ischemia

1989 ◽  
Vol 70 (4) ◽  
pp. 612-618 ◽  
Author(s):  
Isabelle M. Germano ◽  
Lawrence H. Pitts ◽  
Isabelle Berry ◽  
Michael Moseley
Keyword(s):  
Cerebral Ischemia ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Focal Cerebral Ischemia ◽  
High Energy ◽  
Control Group ◽  
Resonance Spectroscopy ◽  
Mr Images ◽  
Ischemic Insult

✓ Recent advances in magnetic resonance (MR) imaging and MR spectroscopy (MRS) allow the noninvasive in vivo study of a variety of anatomical, physiological, and biochemical alterations that may occur in different cerebral pathologies. The authors have investigated the use of MR imaging and MRS to monitor the evolution of experimental focal cerebral ischemia in rats. Permanent focal cerebral ischemia was induced in 36 rats, and 12 normal rats were used as a control group. Changes in high-energy phosphate metabolites were followed in vivo using MRS during the 1st hour and at 3 and 6 hours after ischemic insult. Changes in in vivo MR images were evaluated at 1, 3, 6, 12, and 24 hours after ischemic insult. Significant decreases (p < 0.05) in phosphocreatine/inorganic phosphate ratios and intracellular pH values occurred immediately after the induction of ischemia. The presence of an infarcted area seen on MR images was a constant finding at 3 hours after ischemic insult, and was well defined and localized at 12 and 24 hours. The location of areas of infarction seen on MR images correlated well with areas identified histopathologically. The T1 and T2 MR relaxation times were significantly increased 3 hours after ischemic insult and remained prolonged for at least 24 hours. The results show that MR imaging is a sensitive method to measure cerebral infarction, and that MRS is a sensitive measure of changes that occur in the early phases of ischemia, perhaps when cellular changes may still be reversible. At 3 and 6 hours after the ischemic insult, however, 31P-MRS spectra may appear to be “normal” despite the presence of well-documented areas of infarction.

scholarly journals High Energy Phosphate Metabolism in Experimental Permanent Focal Cerebral Ischemia: An in vivo 31P Magnetic Resonance Spectroscopy Study

1988 ◽  
Vol 8 (1) ◽  
pp. 24-31 ◽  
Author(s):  
Isabelle M. Germano ◽  
Lawrence H. Pitts ◽  
Isabelle Berry ◽  
Stephen J. de Armond
Keyword(s):  
Cerebral Ischemia ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Focal Cerebral Ischemia ◽  
High Energy ◽  
Resonance Spectroscopy ◽  
Sprague Dawley ◽  
Hypoxia Group ◽  
Mild Hypoxia

Relative levels of phosphate metabolites in the brain were examined in vivo by 31P magnetic resonance spectroscopy (MRS) in 50 Sprague-Dawley rats before, during, and after induction of focal permanent cerebral ischemia. After acquisition of baseline spectra, rats were subjected to injury within the core of the MR spectrometer, and 31P spectra were collected for 60 min after injury: in 7 rats, permanent, acute focal cerebral ischemia was induced (ischemia group); in 6 rats, mild hypoxia (FiO2 14%) was induced at the time of the ischemic insult and was maintained for 20 min (ischemia-hypoxia group); in 6 rats, mild hypoxia (FiO2 14%) only was induced for 20 min (hypoxia group). Control studies were performed in 25 rats. Cerebral intracellular pH, calculated from the chemical shift of inorganic phosphate (Pi), decreased immediately after injury in the ischemia and ischemia-hypoxia groups. The first 31P spectrum obtained after injury was characterized by an increase in Pi and a decrease in phosphocreatine (PCr) in the ischemia and ischemia-hypoxia groups; these changes in spectra were significantly greater in the ischemia-hypoxia group. No significant changes in adenosine triphosphate (ATP) were found in either group. Within 60 min of occlusion, 31P spectra returned toward baseline spectra in both ischemia-hypoxia and ischemia groups. No significant changes were seen in spectra of rats subjected to hypoxia alone. These results confirm that 31P MRS is a sensitive measure of early changes of high energy metabolites in focal cerebral ischemia. The return of spectra toward baseline values within 1 h of injury despite the presence of permanent ischemic damage, however, suggests that caution should be used in attempts to interpret “recovery” of 31P MRS.

Cardiac energetics alteration in chronic hypoxia rat model: a non invasive in vivo 31P magnetic resonance spectroscopy experimental study

2021 ◽  
Author(s):  
Xiaohan Yuan ◽  
Xiaomei Zhu ◽  
Yang Chen ◽  
Wangyan Liu ◽  
Wen Qian ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Right Ventricular ◽  
Myocardial Injury ◽  
Chronic Hypoxia ◽  
Volume Index ◽  
Control Group ◽  
Resonance Spectroscopy ◽  
Cardiac Energetics

Abstract Background: Energetics alteration plays a key role in the process of myocardial injury in chronic hypoxic diseases (CHD). 31P magnetic resonance spectroscopy (MRS) can investigate alterations in cardiac energetics in vivo. This study was aimed to characterize the potential value of 31P MRS in evaluating cardiac energetics alteration of chronic hypoxia rats (CHR).Methods: Twenty-four CHRs were induced by SU5416 combined with hypoxia, and six rats were raised as control group. 31P MRS was performed weekly and the ratio of concentrations of phosphocreatine (PCr) to adenosine triphosphate (ATP) (PCr/ATP) was obtained. The index of cardiac structure and systolic function parameters, including the right ventricular function (RVEF), right ventricular end-diastolic volume index (RVEDVi), right ventricular end-systolic volume index (RVESVi), the left ventricular function parameters were also measured.Results: The declension of resting cardiac PCr/ATP ratio in CHR was observed at the 1st week, compared to control group (2.90±0.35 vs. 3.31±0.45, p =0.045), while the RVEF，RVEDVi and RVESVi decreased at the 2nd week (p＜0.05). The PCr/ATP ratio displayed a significant correlation with RVEF(r = 0.605, p = 0.001)，RVEDVi and RVESVi (r = -0.661, r = -0.703; p＜0.001).Conclusions: 31P MRS can early detect the cardiac energetics alteration in CHR model before the onset of ventricular dysfunction. The decrease of PCr/ATP ratio likely revealed myocardial injury and cardiac dysfunction.

A review of in vivo 1H magnetic resonance spectroscopy of cerebral ischemia in rats

1998 ◽  
Vol 76 (2-3) ◽  
pp. 487-496 ◽  
Author(s):  
K L Malisza ◽  
P Kozlowski ◽  
J Peeling
Keyword(s):  
Cerebral Ischemia ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Lactate Concentration ◽  
Dichloroacetic Acid ◽  
Proton Nuclear Magnetic Resonance ◽  
Effect Of Temperature ◽  
Resonance Spectroscopy ◽  
Ischemic Damage

A number of metabolic alterations are initiated by cerebral ischemia including dramatic increases in lactate concentration, decreases in N-acetylaspartate, choline, and creatine concentrations, as well as changes in amino acid levels. A review of proton nuclear magnetic resonance spectroscopy studies of focal and global cerebral ischemia in rats is presented here. In particular, studies in neonatal rats have shown that a continued elevation of lactate levels without recovery after hypoxia-ischemia or a decrease in N-acetylaspartate concentration at any time are indicative of deleterious outcome. Studies of the effect of temperature on ischemic damage in a model of focal ischemia showed that outcome improved with mild hypothermia. Again, lack of recovery of lactate upon reperfusion was shown to be indicative of poor outcome. Dichloroacetic acid was used to treat rats with focal ischemic damage. Animals subjected to transient ischemia that were treated with dichloroacetic acid showed significant decreases in lactate concentration.Key words: NMR, in vivo, rat, cerebral ischemia.

scholarly journals Influence of hyperglycemia on cerebral ischemia studied by in vivo magnetic resonance spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 50
Author(s):  
Yoshikazu Kurigayashi ◽  
Hiroaki Naritomi ◽  
Masahiro Sasaki ◽  
Masaru Kanashiro ◽  
Tetsuzo Tagawa ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy
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