Modifications of relaxation times induced by radiation therapy in cervical carcinoma: preliminary results

Pelvic Magnetic Resonance Imaging (MRI) was performed in eight healthy women and in eight patients with carcinoma of the cervix, using a 0.5 T superconductive magnet, to evaluate relaxation times of the normal uterine cervix and carcinomas. Spin-lattice (T1) and spin-spin (T2) relaxation times for skeletal muscle, adipose tissue and bone marrow of the epiphysis of the femur were also measured in all cases. In the group of patients with carcinoma of the cervix MRI was performed before, during and after radiation therapy. The mean T1 and T2 values for the normal uterine cervix and cervical carcinoma were evaluated. Mean spin-lattice time for carcinomas were confirmed to be higher than the mean calculated value for the normal cervix, while no significant variation was observed with respect to spin-spin time. A high individual T1 and T2 variability was noted not only in the group of patients affected by cervical carcinoma, but among the healthy subjects too. After radiation therapy a mean T1 time reduction of approximately 20% was found in cervical carcinomas compared with pretreatment measurements, whereas no difference was evident for T2 time. These preliminary results confirm that reduction in spin-lattice time is demonstrated in tumours submitted to radiation therapy. More detailed biological information, such as percentages of vital and necrotic cells, tissue water content and cellular kinetics are probably necessary for a clearer understanding of this phenomenon even in an apparently homogeneous group of patients.