Liver metastasis: comparison of 2 methods for reporting of disease in patients receiving chemotherapy

Objective: To compare bidimensional measurements with direct volumetry in t he reporting of disease in patients with liver metastases who are receiving chemotherapy. Patients and methods: Ten patients (6 men and 4 women) recei ving chemotherapy were included. A total of 37 contrast-enhhanced abdominal computed tomographic (CT) scans, forming 26 pairs of studies, were evaluat ed retrospectively by 2 independent reviewers. One reviewer recorded bidime nsional measurements from hard-copy films, and the other recorded volumetri c measurements at the CT console. All measurements were analysed before and after application of a 5% variation interval. Results: Reporting of diseas e was initially discordant in 5 (19%) of the 26 paired examinations. After application of a 5% variation interval, 9 cases (35%) were discordant. When borderline results (type of response modified by 5% variation) were exclud ed, 4 discordant cases (20%) remained. All but 1 case showed progressive di sease with bidimensional measurements and no change at volumetry. The prese nce of a new lesion affected reporting in only 1 case. Conclusion: The 2 me thods of reporting disease are not interchangeable. We believe that volumet ric measurements are more representative of tumour burden than bidimensiona l measurements. However, acquisition of nonhelical data may be a pitfall in volumetric measurements. The increasing availability of helical CT technol ogy should resolve this issue.