A rapid, radiation-free magnetic resonance imaging (MRI) method that simultaneously captures bone-selective (pseudo-CT) bone images and high-resolution T1- and T2-weighted soft-tissue images in a single, self-registered 3D scan.

MRI excels at visualizing soft tissue, but capturing high-quality images of rigid structures like cortical bone remains technically difficult, so CT is still the clinical standard for detailed bone assessment. Recent MRI advances can image bone or soft tissue, but each contrast (bone-selective, T1-weighted, and T2-weighted) typically requires its own dedicated sequence and scan time. As a result, there is currently no single, routine MRI protocol that provides CT-like bone detail together with multiple soft-tissue contrasts in one rapid, 3D, radiation-free scan.

Dr. Chamith Rajapakse’s team developed DREAMER (“Dual Repetition and Echo Acquisition with Multi-contrast Encoding and Reconstruction”), a single, rapid MRI sequence that generates high-quality bone-selective images together with T1- and T2-weighted soft tissue images in one 3D, radiation-free scan, reducing or potentially eliminating the need for separate CT examinations. Because all three key contrasts – bone-selective, T1-weighted, and T2-weighted – are acquired in a single, self-registered 3D volume, DREAMER can consolidate what would otherwise require multiple MRI sequences plus a separate CT study. This integrated workflow shortens overall imaging time, simplifies scheduling and interpretation, and avoids ionizing radiation exposure.

DREAMER exploits the fact that soft tissues have relatively long T2 relaxation times, whereas mineralized bone has very short T2, by acquiring two echoes after each RF pulse: an ultrashort echo that preserves rapidly decaying bone signal, and a later, conventional echo optimized for soft-tissue contrast. The sequence encodes additional T2-weighting in the phase of the complex-valued MRI signal, allowing retrospective adjustment of T1- and T2-weighted soft tissue images from the same dataset. A normalized ultrashort-conventional echo subtraction isolates short-T2 bone signal to produce high-contrast, bone-selective images.

• Simultaneous imaging of solid (bone) and soft tissues in a single scan
• Reduced overall MRI examination time
• High resolution, 3D isotropic images
• Retrospectively tunable soft-tissue contrast, including T1- and T2-weighted images, from the same dataset
• Potential to avoid separate CT scans and thus eliminate exposure to ionizing radiation 
• All output images (bone-selective, T1-weighted, and T2-weighted) are inherently co-registered