Wang L, Zhu H Y, Tian J M, Huang S D, Kong L S, Lu J P
Department of Radiology, Changhai Hospital, Second Military Medical University, Shanghai, China.
Acta Radiol. 2007 Jun;48(5):500-7. doi: 10.1080/02841850701280783.
In patients with chronic left ventricular dysfunction, the size of the viable cardiac muscle is correlated with the prognosis and the outcome of myocardial revascularization.
To evaluate the diagnostic value of various imaging techniques in determination of myocardial ischemia and viability.
A chronic myocardial ischemia animal model was established, in which 10 pigs underwent magnetic resonance imaging (MRI), positron emission tomography (PET), and single-photon emission computed tomography (201Tl SPECT) before and 1-2 months after modeling. The size of myocardial ischemia and necrosis was judged, and the imaging manifestations were compared with pathologic findings.
Seven of the 10 animals completed all examinations uneventfully. On dobutamine-stressed cine MRI, 10 (8.93%) segments were found to be akinetic. Perfusion was abnormal in 34 (30.35%) segments. Delayed hyperenhancement was observed in 12 (10.71%) segments. PET detected myocardial necrosis in 17 (15.18%) segments, and SPECT detected myocardial necrosis in nine (8.04%) segments. Histological examination with triphenyltetrazolium chloride (TTC) showed pale necrosis in 14 (12.50%) segments. The number of necrotic segments detected by PET was significantly greater than that by contrast-enhanced MRI (chi2 = 5, P = 0.0253, kappa = 0.8028) and cine MRI (chi2 = 7, P = 0.0082, kappa = 0.7079). It was also greater than that by TTC (chi2 = 3, P = 0.0833, kappa = 0.8879), although the difference was statistically insignificant. The number of necrotic segments detected by SPECT was significantly smaller than that by TTC (chi2 = 5, P = 0.0253, kappa = 0.7590), as was the number of necrotic segments detected by cine MRI (chi2 = 4, P = 0.0455, kappa = 0.8100). There was no statistically significant difference in the detection of necrotic segments between contrast-enhanced MRI and TTC (chi2 = 2, P = 0.1573, kappa = 0.9130).
Cardiac MRI can determine viable myocardium and clearly delineate the location and degree of myocardial necrosis. PET slightly overestimates the extent of the necrotic myocardium and is unable to distinguish transmural necrosis from subendocardial necrosis.
在慢性左心室功能不全患者中，存活心肌的大小与预后及心肌血运重建的结果相关。
评估各种成像技术在判定心肌缺血和存活心肌方面的诊断价值。
建立慢性心肌缺血动物模型，10头猪在建模前及建模后1 - 2个月接受磁共振成像（MRI）、正电子发射断层扫描（PET）和单光子发射计算机断层扫描（201Tl SPECT）检查。判断心肌缺血和坏死的范围，并将成像表现与病理结果进行比较。
10只动物中有7只顺利完成所有检查。在多巴酚丁胺负荷心脏电影MRI上，发现10个节段（8.93%）运动减弱。34个节段（30.35%）灌注异常。12个节段（10.71%）出现延迟强化。PET检测到17个节段（15.18%）心肌坏死，SPECT检测到9个节段（8.04%）心肌坏死。用氯化三苯基四氮唑（TTC）进行组织学检查显示14个节段（12.50%）呈苍白坏死。PET检测到的坏死节段数量显著多于对比增强MRI（χ2 = 5，P = 0.0253，kappa = 0.8028）和心脏电影MRI（χ2 = 7，P = 0.0082，kappa = 0.7079）。也多于TTC检测到的数量（χ2 = 3，P = 0.0833，kappa = 0.8879），尽管差异无统计学意义。SPECT检测到的坏死节段数量显著少于TTC（χ2 = 5，P = 0.0253，kappa = 0.7590），心脏电影MRI检测到的坏死节段数量也少于TTC（χ2 = 4，P = 0.0455，kappa = 0.8100）。对比增强MRI与TTC在坏死节段检测方面无统计学显著差异（χ2 = 2，P = 0.1573，kappa = 0.9130）。
心脏MRI能够判定存活心肌，并清晰显示心肌坏死的部位和程度。PET对坏死心肌范围略有高估，且无法区分透壁性坏死与心内膜下坏死。
