The objectives of the study were to determine whether perfusion computed tomography (CT-p) and magnetic resonance diffusion-weighted imaging (MR-DWI) can allow evaluation of the effects of chemotherapy combined with antiangiogenetic treatment on liver metastases in patients with advanced colorectal cancer and to determine if changes in CT-p and MR-DWI correlate with the response to therapy as assessed by conventional Response Evaluation Criteria in Solid Tumors (RECIST).
Eighteen patients with liver metastases from colorectal cancer underwent CT-p and MR-DWI before and 6 months after chemotherapy and antiangiogenetic treatment. Lesions were classified according to RECIST criteria (complete response [CR], partial response [PR], stable disease [SD], and progressive disease) and calculations of CT-p parameters including blood flow (BF), blood volume (BV), capillary permeability (CP), and MR-DWI apparent diffusion coefficient (ADC) values were performed; RECIST, CT-p, and MR-DWI measurements at baseline and follow-up were tested for statistically significant differences using the paired-samples t test. Baseline and follow-up perfusion parameters of the lesions were also compared on the basis of therapy response assessed by RECIST criteria using independent-samples t test. P < 0.05 was considered indicative of a statistically significant difference for all statistical test.
Six patients (6/18; 33.3%) were classified as PR (Fig. 1), and the remaining 12 (12/18; 66.7%) were classified as SD. On a per-lesion basis, 2 (2/32; 6.3%) cannot be identified at follow-up, 6 (6/32; 18.8%) showed a decrease in size of more than 30%, and 24 (24/32; 75%) were substantially stable in size. No cases of progressive disease were demonstrated at follow-up. No statistically significant differences were demonstrated between PR, CR, and SD lesions for BF (P = 0.19), BV (P = 0.14), and ADC (P = 0.68) measurements, whereas CP was significantly higher in CR and PR lesions (P = 0.038). Considering differences between baseline and follow-up values, no statistically significant differences were noted between PR and CR lesions versus SD lesions for CT-p values (BF: P = 0.77; BV: P = 0.15; CP: P = 0.64). A statistically significant difference between PR and CR lesions and SD lesions was noted for ADC values (P = 0.047).
Both CT-p and MR-DWI can detect therapy-induced modifications in lesion vascularization before significant changes in size are evident.
From the *Department of Radiological Sciences, University of Rome “La Sapienza,” Rome; and †Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari–Polo di Monserrato, Monserrato, Cagliari, Italy.
Received for publication May 13, 2011; accepted August 1, 2011.
Reprints: Michele Anzidei, MD, Department of Radiological Sciences, University of Rome “La Sapienza,” Viale Regina Elena 324, 00161, Rome, Italy (e-mail: firstname.lastname@example.org).
Author contributions: Guarantors of integrity of entire study: C.C., A.N., R.P.; study concepts/study design or data acquisition or data analysis/interpretation: C.C., A.N., M.A.; manuscript drafting or manuscript revision for important intellectual content: all authors; approval of final version of submitted manuscript: all authors; literature research: all authors; clinical and experimental studies: C.C., A.N., M.A; statistical analysis: F.Z.; and manuscript editing: all authors.
For all authors, there is no potential conflict of interest that could be perceived to bias our work. The authors had full control of all the data and information presented in this article.
Written informed consent was obtained by all the patients involved in the study, and the whole study protocol was approved by the local ethics committee.