MRIohjattu

MRIohjattu, commonly translated as MR-guided, refers to medical procedures in which magnetic resonance imaging is used to plan, monitor, and guide instruments such as needles, catheters, or probes during intervention. The approach leverages the high soft-tissue contrast and multiplanar capabilities of MRI to visualize targets and surrounding structures without ionizing radiation.

Applications include interventional radiology and oncology, where MRI guidance supports procedures such as biopsy of liver, prostate, kidney, or breast lesions; ablation therapies (e.g., laser interstitial thermal therapy, radiofrequency or cryoablation); and targeted drug or gene delivery. In neurosurgery, MRI guidance assists stereotactic placement of implants or probes, and may be used in other organ systems where precise localization is essential. Integrated with robotic systems or surgical navigation, MRI guidance can improve accuracy and safety.

Advantages include superior soft-tissue delineation, real-time verification of instrument position, and the ability to track functional responses such as perfusion or diffusion changes during the procedure. MRI does not involve ionizing radiation, which is beneficial for patients requiring multiple procedures or young patients. Limitations include the need for MR-compatible equipment, higher equipment and facility costs, longer procedure times, and the need for specialized personnel and workflows. The strong magnetic field and acoustic noise pose safety and comfort considerations.

History and development of MRI-guided interventions began in the late 20th century and expanded with advances in rapid MR imaging sequences, navigation software, and MR-compatible instruments. Ongoing research focuses on improving real-time imaging speed, integrating robotics, and expanding indications, including theranostic approaches that combine imaging and therapy.