BACKGROUND
The purpose of this work was to further define the value of cardiac 31P magnetic resonance (MR) spectroscopy for patients with coronary artery disease and dilated cardiomyopathy.
METHODS AND RESULTS
Blood-corrected and T1-corrected 31P MR spectra of anteroseptal myocardium were obtained at rest using image-selected in vivo spectroscopy localization, a selected volume of 85 +/- 12 cm3, and a field strength of 1.5 T. Nineteen volunteers had a creatine phosphate (CP)/ATP ratio of 1.95 +/- 0.45 (mean +/- SD) and a PDE/ATP ratio of 1.06 +/- 0.53; in four patients with left anterior descending coronary artery (LAD) stenosis, six patients with chronic anterior wall infarction, and four patients with chronic posterior wall infarction, CP/ATP and phosphodiester (PDE)/ATP ratios did not differ from those in volunteers. Twenty-five measurements of 19 patients with dilated cardiomyopathy yielded a CP/ATP of 1.78 +/- 0.51 and a PDE/ATP of 0.98 +/- 0.56 (p = NS versus volunteers). When these patients were grouped according to the severity of heart failure, however, CP/ATP was 1.94 +/- 0.43 in mild (p = NS versus volunteers) and 1.44 +/- 0.52 in severe DCM (p < 0.05), respectively. No correlation was found between CP/ATP and left ventricular ejection fraction or fractional shortening, but correlation of CP/ATP with the New York Heart Association (NYHA) class was significant (r = 0.60, p < 0.005). Six patients with dilated cardiomyopathy were studied repeatedly before and after 12 +/- 6 weeks of drug treatment leading to clinical recompensation with improvement of the NYHA status by 0.8 +/- 0.3 classes. Concomitantly, CP/ATP increased from 1.51 +/- 0.32 to 2.15 +/- 0.27 (p < 0.01), whereas PDE/ATP did not change significantly.
CONCLUSIONS
Cardiac high-energy phosphate metabolism at rest is normal in LAD stenosis and chronic myocardial infarction in the absence of heart failure. The CP/ATP ratio has low specificity for the diagnosis of dilated cardiomyopathy. However, CP/ATP correlated with the clinical severity of heart failure and may improve during clinical recompensation.
US-guided percutaneous injection of thrombin is successful and safe in the management of femoral pseudoaneurysms. The increase of thrombin-antithrombin III complex indicates the possibility of thrombin passage into the arterial circulation.
Localized phosphorus-31 MR spectra were obtained in vivo in a large series of normal human brain tissue specimens of healthy volunteers (n=36) and various brain tumours (n=52). Tumour types examined included grade II and grade III gliomas (n=15 and n=1, respectively), glioblastomas (n=16) and meningeomas (n=12). An additional eight tumours were analysed during chemo- or radiotherapy. Spectra were acquired using a modified ISIS pulse sequence with a repetition time of 3 s. Voxel sizes ranged from 56 to 129 ml. The spectra were evaluated using a least-square variable projection (VARPRO) fitting procedure in the time domain, which allows semi-quantitative determination of relative metabolite concentrations. The measurements in normal cerebrum of healthy volunteers revealed the following results of metabolite signal intensity ratios: pH 7.04 (+/- 0.01), PCr/alpha-ATP 0.51 (+/- 0.03), P(i)/alpha-ATP 0.17 (+/-0.02), PCr/P(i) 2.09 (+/-0.12), PDE/alpha-ATP 3.65 (+/-0.13) and PME/alpha-ATP 0.41 (+/-0.04). Meningiomas showed the most obvious changes when compared with normal brain tissue. They are characterized by an alkaline environment (pH 7.16 +/- 0.03; p<0.005), a decrease in the phosphocreatine peak (p<0.0001) and significantly decreased phosphodiesters (p<0.0001). Glioblastomas also showed alkalization (pH 7.12 +/- 0.02; p<0.001) and a decrease in PDE/alpha-NTP (p<0.05), but no significant changes in PCr/alpha-NTP or PCr/Pi. In gliomas with low malignancy, less distinct changes could be detected with slight alkalization (pH 7.09 +/- 0.02; p<0.05) and more than a two-fold reduction in the PDE/alpha-NTP ratio (p<0.05). The spectra of brain tumours during chemo- and radiotherapy indicated clear but inconsistent influence of the therapy.
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