In vivo magnetic resonance imaging of a mouse model of myelofibrosis

Myelofibrosis is a slowly evolving pathology, characterized by increased myeloid cells and structural abnormality of the bone marrow matrix, which at end-stage manifests in excessive deposition of reticulin fibers and cross-linked collagen in the bone marrow, suppression of normal hematopoiesis and bone marrow failure. Clinically, myelofibrosis occurs secondary to a variety of hematologic conditions, but is mostly associated with primary myelofibrosis (PMF). Histological features of overt PMF include bone marrow with abundant reticulin/collagen fibers and later-stage osteosclerosis, although the pre-fibrotic stage mainly exhibits an abundance of megakaryocytes. Although histopathology of bone marrow aspirates is the current standard for PMF diagnosis, magnetic resonance imaging (MRI) can provide non-invasive serial three-dimensional imaging of the bone marrow in contrast to restrictive clinical biopsydependent or murine end-stage conventional histology. Recognizing the potential of MRI to identify advanced myelofibrosis, a published study focused on T1-weighted MRI of bone marrow in overt-to-advanced PMF patients. Matching MRI images to biopsy– histologic studies has shown clinical feasibility of MRI, as a noninvasive method of determining extent of myelofibrosis combined with biopsy findings. Application of T1-weighted spin echo (T1-SE) and short T1-inversion recovery sequences showed a