MR-compatible treadmill for exercise stress cardiac magnetic resonance imaging.

This article describes an MR-safe treadmill that enables cardiovascular exercise stress testing adjacent to the MRI system, facilitating cardiac MR imaging immediately following exercise stress. The treadmill was constructed of nonferromagnetic components utilizing a hydraulic power system. Computer control ensured precise execution of the standard Bruce treadmill protocol commonly used for cardiovascular exercise stress testing.

A new approach to autocalibrated dynamic parallel imaging based on the Karhunen-Loeve transform: KL-TSENSE and KL-TGRAPPA.

TSENSE and TGRAPPA are autocalibrated parallel imaging techniques that can improve the temporal resolution and/or spatial resolution in dynamic magnetic resonance imaging applications. In its original form, TSENSE uses temporal low-pass filtering of the undersampled frames to create the sensitivity map. TGRAPPA uses a sliding-window moving average when finding the autocalibrating signals.

Magnetic field threshold for accurate electrocardiography in the MRI environment.

Although the electrocardiogram is known to be nondiagnostic within the bore of any high-field magnet due to the magnetohydrodynamic effect, there are an increasing number of applications that require accurate electrocardiogram monitoring of a patient inside the MRI room but outside of the magnet bore. Magnetohydrodynamic effects on the ST segment of the electrocardiogram waveform were investigated in six subjects at magnetic field strengths ranging from 6.4 mT to 652 mT at the aortic midarch, and the electrocardiogram was found to be accurate at magnetic fields below 70 mT.

Real-time cine and myocardial perfusion with treadmill exercise stress cardiovascular magnetic resonance in patients referred for stress SPECT.

Background: To date, stress cardiovascular magnetic resonance (CMR) has relied on pharmacologic agents, and therefore lacked the physiologic information available only with exercise stress.

Methods: 43 patients age 25 to 81 years underwent a treadmill stress test incorporating both Tc99m SPECT and CMR. After rest Tc99m SPECT imaging, patients underwent resting cine CMR.

Cardiac function and myocardial perfusion immediately following maximal treadmill exercise inside the MRI room.

Treadmill exercise stress testing is an essential tool in the prevention, detection, and treatment of a broad spectrum of cardiovascular disease. After maximal exercise, cardiac images at peak stress are typically acquired using nuclear scintigraphy or echocardiography, both of which have inherent limitations. Although CMR offers superior image quality, the lack of MRI-compatible exercise and monitoring equipment has prevented the realization of treadmill exercise CMR.