Fundamental tumor perfusion analysis with nuclear magnetic resonance imaging using gadolinium-diethylene triamine...

The measurement of blood perfusion is an important factor for both the diagnosis and follow-up of tumor lesions. However, noninvasive detection of this local blood flow factor is very difficult. To accomplish this, we tried to calculate tissue blood perfusion indexes with nuclear magnetic resonance imaging using gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA). We experimentally applied this method to C3H mouse's tumor NFSa (fibrosarcoma) and its recurrence tumor R1137, whose experimental hypoxic cell fraction is different; that is, R1137 is more oxic than NFSa. Imaging pulse sequence was T1 (TR = 1,000 ms, TI = 300 ms), and longitudinal relaxation rate (R1 = 1/T1) values were calculated. Injected dose of Gd-DTPA was 0.1 mmol/kg. The T1 images produced are from both the preinjection period from every 5 min postinjection for 30 min. Using two-exponential analysis and compartment analysis we calculated two fundamental parameters: uptake index and flow index as blood perfusion factors. We found that this method has the possibility of differentiating the tissue's hypoxic cell fraction and is effective both for follow-up study after radiation therapy and for tissue characterization.