Tumour oxygenation levels correlate with dynamic contrast-enhanced magnetic resonance imaging parameters in carcinoma of the cervix

Background and purpose: The Eppendorf pO(2) histograph is the 'gold standar d' method for measuring tumour oxygenation. The method is not suitable for widespread application because its use is limited to accessible rumours. A non-invasive imaging technique would be an attractive alternative. Therefor e, the relationships between tumour oxygenation and dynamic contrast-enhanc ed magnetic resonance imaging (MRL) parameters were investigated. Materials and Methods: The study comprised 30 patients with carcinoma of th e cervix. Tumour oxygenation was measured pre-treatment as median pO(2) and the proportion of values less than 5 mmHg (HP5) using a pO(2) histograph. Repeat measurements were obtained for nine patients following 40-45 Gy exte rnal beam radiotherapy giving a total of 39 measurements. Dynamic contrast- enhanced MRI using gadolinium was performed prior to obtaining the oxygenat ion data. Time/signal intensity curves were generated to obtain two standar d parameters: maximum enhancement over baseline (SI-I) and the rate of enha ncement (SI-I/s). Results: Using the 39 measurements, there was a significant correlation bet ween SI-I and both median pO(2) (r = 0.59; P < 0.001) and HP5 (r = -0.49; P = 0.002). There was a weak, borderline significant correlation between SI - I/s and both median pO(2) (r = 0.29; P = 0.071) and HP5 (r = -0.34; P = 0 .037). There was a significant relationship between tumour size and SI-I (r = 0.54; P < 0.001), but not SI - I/s. In 29 tumours, where data were avail able, there was no relationship between histological assessment of tumour a ngiogenesis (intra-tumour microvessel density; IMD) and either MRI paramete r. Conclusions: Tumour oxygenation levels measured using a pO(2) histograph co rrelate with dynamic contrast-enhanced MRI parameters. Therefore, non-invas ive dynamic MRI may be a method for measuring hypoxia in human tumours. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.