Xenon-Inhalation Computed Tomography for Noninvasive Quantitative Measurement of Tissue Blood Flow in Pancreatic Tumor

The purpose of this prospective study was to demonstrate the ability to measure pancreatic tumor tissue blood flow (TBF) with a noninvasive method using xenon inhalation computed tomography (xenon-CT) and to correlate TBF with histological features, particularly microvascular density (MVD). TBFs of pancreatic tumors in 14 consecutive patients were measured by means of xenon-CT at diagnosis and following therapy. Serial abdominal CT scans were obtained before and after inhalation of nonradioactive xenon gas. TBF was calculated using the Fick principle. Furthermore, intratumoral microvessels were stained with anti-CD34 monoclonal antibodies before being quantified by light microscopy (x200). We evaluated MVD based on CD34 expression and correlated it with TBF. The quantitative TBF of pancreatic tumors measured by xenon CT ranged from 22.3 to 111.4 ml/min/100 g (mean +/- A SD, 59.6 +/- A 43.9 ml/min/100 g). High correlation (r = 0.885, P < 0.001) was observed between TBF and intratumoral MVD. Xenon-CT is feasible in patients with pancreatic tumors and is able to accurately estimate MVD noninvasively.