Safety of brain 3-T MR imaging with transmit-receive head coil in patients with cardiac pacemakers: pilot prospective study with 51 examinations

PURPOSE: To evaluate the safety and feasibility of 3-T magnetic resonance (MR) imaging of the brain in patients with implanted cardiac pacemakers (PMs) by using a transmit-receive head coil. MATERIALS AND METHODS: The study protocol was approved by the institutional review board. Signed informed consent was obtained from all subjects. In vitro testing at 3 T was performed with 32 PMs and 45 PM leads that were evaluated for force and torque (by using a floating platform) and radiofrequency (RF)-related heating by using a transmit-receive head coil (maximum specific absorption rate, 3.2 W/kg). Patient examinations at 3 T were performed in 44 patients with a cardiac PM and a strong clinical need; patients underwent a total of 51 MR examinations of the brain by using a transmit-receive head coil to minimize RF exposure of the PM system. An electrocardiograph and pulse oximetry were used for continuous monitoring during MR imaging. The technical and functional PM status was assessed prior to and immediately after MR imaging and at 3 months thereafter. Serum troponin I level was measured before and 12 hours after imaging to detect myocardial thermal injury. PM reprogramming was performed prior to MR imaging depending on the patient's intrinsic heart rate ( or = 60 beats per minute, sense-only mode). RESULTS: For in vitro testing, the maximum translational force was 2150 mN (mean, 374.38 mN +/- 392.75 [standard deviation]), and maximum torque was 17.8 x 10(-3) N x m (mean, [2.29 +/- 4.08] x 10(-3) N x m). The maximum temperature increase was 2.98 degrees C (mean, 0.16 degrees C +/- 0.45). For patient examinations, all MR examinations (51 of 51) were completed safely. There were no significant (P < .05) changes in lead impedance, pacing capture threshold level, or serum troponin I level. CONCLUSION: MR imaging of the brain at 3 T in patients with a cardiac PM can be performed safely when dedicated safety precautions (including the use of a transmit-receive head coil) are taken

25 Years of Contrast-Enhanced MRI : Developments, Current Challenges and Future Perspectives

UNLABELLED: In 1988, the first contrast agent specifically designed for magnetic resonance imaging (MRI), gadopentetate dimeglumine (Magnevist(®)), became available for clinical use. Since then, a plethora of studies have investigated the potential of MRI contrast agents for diagnostic imaging across the body, including the central nervous system, heart and circulation, breast, lungs, the gastrointestinal, genitourinary, musculoskeletal and lymphatic systems, and even the skin. Today, after 25 years of contrast-enhanced (CE-) MRI in clinical practice, the utility of this diagnostic imaging modality has expanded beyond initial expectations to become an essential tool for disease diagnosis and management worldwide. CE-MRI continues to evolve, with new techniques, advanced technologies, and novel contrast agents bringing exciting opportunities for more sensitive, targeted imaging and improved patient management, along with associated clinical challenges. This review aims to provide an overview on the history of MRI and contrast media development, to highlight certain key advances in the clinical development of CE-MRI, to outline current technical trends and clinical challenges, and to suggest some important future perspectives. FUNDING: Bayer HealthCare