Morikawa S, Inubushi T, Kito K
Molecular Neurobiology Research Center, Shiga University of Medical Science, Ohtsu, Japan.
Cardiovasc Surg. 1993 Aug;1(4):337-42.
Non-localized and localized 31P nuclear magnetic resonance (NMR) spectra of rat calf muscle during arterial occlusion and after reperfusion were concurrently observed using chemical shift imaging and 1H magnetic resonance imaging (MRI). During ischaemia, the levels of high-energy phosphates (phosphocreatine and adenosine 5'-triphosphate) were depleted and that of inorganic phosphate was increased. In addition, the signal intensity on 1H MRI was increased. These changes were observed to be relatively homogeneous throughout the calf. In contrast, the changes during reperfusion were heterogeneous. In the central part of the calf, inorganic phosphate disappeared, phosphocreatine was restored immediately on reperfusion and the 1H signal was decreased. However, in the regions of the tibialis anterior muscle and the superficial part of the gastrocnemius muscle, inorganic phosphate persisted for several hours, phosphocreatine was not restored and the signal intensity on T2-weighted 1H MRI was increased further. The heterogeneous changes detected by 31P NMR spectroscopy and 1H MRI showed close agreement. The susceptibility of different calf muscles to ischaemia and reperfusion seems to depend on their predominant muscle fibre type (i.e. fast-twitch or slow-twitch fibres). Reversible and irreversible ischaemic changes could be non-invasively distinguished by in vivo 31P NMR spectroscopy and 1H MRI.
利用化学位移成像和氢质子磁共振成像（MRI），同时观察了大鼠小腿肌肉在动脉闭塞期间及再灌注后的非定位和定位31P核磁共振（NMR）光谱。在缺血期间，高能磷酸盐（磷酸肌酸和腺苷5'-三磷酸）水平降低，无机磷酸盐水平升高。此外，氢质子MRI上的信号强度增加。这些变化在整个小腿中相对均匀。相比之下，再灌注期间的变化是异质性的。在小腿中部，无机磷酸盐消失，再灌注时磷酸肌酸立即恢复，氢质子信号降低。然而，在胫骨前肌和腓肠肌浅表部分区域，无机磷酸盐持续数小时，磷酸肌酸未恢复，T2加权氢质子MRI上的信号强度进一步增加。31P NMR光谱和氢质子MRI检测到的异质性变化显示出密切的一致性。不同小腿肌肉对缺血和再灌注的易感性似乎取决于其主要的肌纤维类型（即快肌纤维或慢肌纤维）。可逆和不可逆的缺血变化可以通过体内31P NMR光谱和氢质子MRI进行无创区分。
