This paper describes a new rapid steady-state T 1 (RSST 1 ) method for mapping the cerebral blood volume fraction (CBVf) by magnetic resonance imaging (MRI). The principle is based on a twocompartment model of the brain (intra-and extravascular), and the effects of paramagnetic contrast agents on the intravascular longitudinal relaxation time T 1 . Using appropriate parameters, an Inversion-Recovery-Fast-Low-Angle-Shot sequence acts like a low pass T 1 filter, suppressing signals from tissues with T 1 bTR (TR = repetition time). It was shown in vivo that, exceeding a particular contrast agent dose, the signal reaches its maximum (corresponding to the intravascular equilibrium magnetization), and is maintained for a duration related to the dose. Acquisitions during this steady state divided by an additional measure of the overall (intra-and extravascular) magnetization at thermal equilibrium provides the CBVf. Experiments were performed on healthy rats at 2.35 T using P760 (Gd 3 + -compound from Guerbet Laboratories) and Gd-DOTA. Because of its high longitudinal relaxivity, P760 is more convenient, and was used to show the feasibility of the method. The CBVf in different structures of the rat brain was compared. The average CBVf for the whole brain slice is 3.29%60.69% (n = 15). The influence of transendothelial water exchange was quantified and transversal relaxation effects were found negligible in microvasculature. Finally, the sensitivity of the method to CBVf increases under hypercapnia was evaluated (1%/mm Hg PaCO 2 ), demonstrating its potential for longitudinal studies and functional MRI. Clinical applications are feasible since equivalent results were obtained with Gd-DOTA.

Schistosomiasis, a neglected tropical disease, is a major cause of chronic morbidity and disability, and premature death. The hepatosplenic form of schistosomiasis is characterized by hepatosplenomegaly, liver fibrosis, portal hypertension and oesophageal varices, whose rupture may cause bleeding and death. We review currently available abdominal imaging modalities and describe their basic principles, strengths, weaknesses, and usefulness in the assessment of hepatosplenic schistosomiasis. Advanced imaging methods are presented that could be of interest for hepatosplenic schistosomiasis evaluation by yielding morphological, functional and molecular parameters of disease progression. We also provide a comprehensive view of preclinical imaging studies and current research objectives such as parasite visualisation in hosts, follow-up of host-immune response, and development of non-invasive quantitative methods for liver fibrosis assessment.