Early Assessment of Colorectal Cancer Patients with Liver Metastases Treated with Antiangiogenic Drugs: The Role of Intravoxel Incoherent Motion in Diffusion-Weighted Imaging

Abstract

PurposeTo assess the feasibility and effectiveness of quantitative intravoxel incoherent motion (IVIM) of Diffusion-weighted imaging (DWI) in the assessment of liver metastases treated with targeted chemotherapy agents.Methods12 patients with unresectable liver metastases from colorectal cancer were enrolled and received neoadjuvant FOLFIRI (5-fluorouracil, leucovorin, irinotecan) plus bevacizumab therapy. DWI was performed for 36 metastases at baseline and after 14 days from starting the treatment. In addition to the basic IVIM metrics, the product between pseudo-diffusivity and perfusion fraction was considered as a descriptor roughly analogous to the flow. Median diffusion parameters of Region of Interest (ROI) were used as representative values for each lesion. Normalized parameters in comparison with the median value of spleen were also collected. The percentual change of the diffusion parameters was calculated. The response to chemotherapy was evaluated according the Response Evaluation Criteria in Solid Tumors (RECIST) as calculated on whole-body CT scan obtained three months after treatment. Mann Whitney test and Receiver operating characteristic (ROC) analysis were performed.Results24 lesions were categorized as responding and 12 as not responding. There was no statistically significant difference among absolute and normalized diffusion parameters between the pretreatment and the post-treatment findings. Instead, the perfusion fraction (fp) values showed a statistical difference between responder and non-responder lesions: sensitivity and specificity of fp variation was 62% and 93%, respectively.ConclusionsIVIM parameters represent a valuable tool in the evaluation of the anti-angiogenic therapy in patients with liver metastases from colorectal cancer. A percentage change of fp represents the most effective DWI marker in the assessment of tumor response.

Intravoxel incoherent motion model&ndash;based analysis of diffusion-weighted magnetic resonance imaging with 3 <em>b</em>-values for response assessment in locoregional therapy of hepatocellular carcinoma

“…The results of increased D ′ and decreased f ′ in responders are in agreement with increased D and decreased f and D * in histologically confirmed coagulation necrosis area of rabbit VX2 tumors after radiofrequency ablation 39. In a recent study, the early response of liver metastases from colorectal cancer to a combined therapy of antiangiogenic plus cytotoxic agents (FOLFIRI plus bevacizumab) was assessed 40. Responders showed unchanged D and D * values, but decreased f values as a sign of reduced microvessel density.…”

Synthesis and Deployment of an Elusive Fluorovinyl Cation Equivalent: Access to Quaternary α-(1′-Fluoro)vinyl Amino Acids as Potential PLP Enzyme Inactivators

“…Examples include α-difluoromethylornithine (DFMO; trypanosomiasis/African sleeping sickness) 26 and 5-fluorouracil (cancer chemotherapy). 27 That said, outfitting AAs with the α-(1′-fluoro)vinyl functionality in place of the α-proton has not been possible heretofore. This would be required if one wished to deploy this trigger in the active sites of PLP-dependent amino acid decarboxylase (AADC) or retroaldolase enzymes, for example.…”

Intravoxel incoherent motion diffusion‐weighted MRI of the abdomen: The effect of fitting algorithms on the accuracy and reliability of the parameters

“…Compared with the conventional mono‐exponential analysis model, which estimates apparent diffusion coefficient (ADC) as an index of overall water movement, IVIM imaging has the advantage of providing a better explanation of the actual DW signal and separate evaluation of diffusion and perfusion changes in tissues . Several prior studies have demonstrated the potential value of IVIM parameters as meaningful imaging biomarkers for assessing various pathological conditions in the abdominal organs and for monitoring therapeutic responses in oncology patients …”