Duewell S, Kasserra C E, Jezzard P, Balaban R S
Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Magn Reson Med. 1996 May;35(5):787-9. doi: 10.1002/mrm.1910350521.
Methemoglobin (MetHb) was evaluated as an intravascular paramagnetic contrast agent. Methemoglobin formation was induced by 4-dimethylaminophenol (4-DMAP), causing a reduction in blood T2* in vitro. The 4-DMAP generated metHb with a time constant of 62 s. A 4-DMAP bolus did not decrease measurably the signal intensity in the in vivo rabbit kidney in the first pass. At steady state, a MetHb concentration of 24.8 +/- 2.3% resulted in a signal decrease of 9.2 +/- 2.6% in the kidney. Methemoglobin is an effective vascular T2* relaxation agent, but the formation of MetHb by 4-DMAP is too slow for first-pass imaging. A more effective conversion agent resulting in a bolus of at least 25% MetHb within 5 s would result in a detectable first-pass signal and a viable contrast technique.
高铁血红蛋白（MetHb）被评估为一种血管内顺磁性造影剂。4-二甲基氨基苯酚（4-DMAP）可诱导高铁血红蛋白的形成，在体外会导致血液T2降低。4-DMAP生成高铁血红蛋白的时间常数为62秒。4-DMAP团注在首次通过时并未使体内兔肾的信号强度出现可测量的降低。在稳态时，高铁血红蛋白浓度为24.8±2.3%会导致肾脏信号降低9.2±2.6%。高铁血红蛋白是一种有效的血管T2弛豫剂，但4-DMAP生成高铁血红蛋白的速度对于首次通过成像来说太慢。一种更有效的转化剂，能在5秒内产生至少25%高铁血红蛋白的团注，将产生可检测的首次通过信号和可行的造影技术。
