Liver perfusion quantification with MR-DCE imaging at 3.0 T for liver fibrosis assessment in patients with chronic liver diseases
Résumé
Liver fibrosis is an important cause of mortality and morbidity in patients with chronic liver diseases. Fibrosis can lead to cirrhosis from which the complications involve 15,000 and 40,000 deaths per year in France and in USA respectively (1,2). The studies investigating the mechanism of hepatic fibrogenesis have shown the reversible aspect of liver fibrosis and have led to the emergence of more effective treatment strategies. However, an early detection and a clinical follow-up of liver fibrosis are still required. While liver biopsy is the gold standard for the diagnosis of chronic liver diseases, inherent risk, interobserver variability and sampling errors makes liver biopsy unusable for the clinical follow up. Thus, a clinical need in the development of non-invasive methods for liver fibrosis assessment has emerged. At 1.5 T, human in-vivo studies have demonstrated that liver perfusion imaging using a MR dynamic contrast enhanced method (MRDCE) has the potential to detect and assess vascular modifications associated to liver fibrosis (3,4). Nevertheless, such methods required the knowledge of the relationship between signal intensity and contrast agent concentration. Authors have used either in-vitro pre-calibrations based on scan preparations with variable concentration of Gd3+ or preparations with variable T1-values. Our objective was to validate a MR protocol at 3.0 T for liver perfusion quantification using MRDCE imaging with an auto-calibrated procedure for tracer concentration quantification. Validation was performed in-vivo on a prospective study including patients with chronic liver diseases.