The validity of tumour diameter assessed by magnetic resonance imaging and gross specimen with regard to tumour volume in cervical cancer patients

We compared the tumour size measured by magnetic resonance imaging (MRI) with that of gross specimen regarding the virtual tumour volume. Eighty three patients with International Federation of Obstetrics and Gynecology (FIGO) stage Ib to IIa cervical cancer underwent MRI before radical hysterectomy. The largest tumour diameter was determined by both MRI and gross specimen measurement. Tumour volume was calculated by the standard technique of multiplying the sum of the areas by the slice thickness. Paired t-test was used to compare the MRI and gross specimen derived diameters. Pearson correlation coefficient was calculated to evaluate the relationship between the tumour size and volume. The mean diameters of the MRI and gross specimen derived tumour measurements were 3.0 cm (standard deviation, 0.9 cm) and 3.5 cm (standard deviation, 1.2 cm) (p < 0.001), respectively. Mean MRI-based tumour volume was 12.5 cm3 (standard deviation, 10.4 cm3). Tumour diameter measured by MRI had a significantly higher correlation with tumour volume measured by MRI (rp = 0.734) compared with that measured on the gross specimen (rp = 0.690; Steiger's Z test, p = 0.019). The tumour diameter measured by MRI was smaller than gross specimen measurement and correlated more closely with tumour volume in patients with cervical cancer. This study illustrates the value of MRI as a tool for tumour size measurement.