Convolution differentiation is a method of suppressing broad underlying spectral lines in order to emphasize narrower spectral lines. Strong smoothing of the spectrum (e.g., by severe negative exponential weighting of the time data) will suppress the narrow lines but minimally affect very broad ones; subtracting such a smoothed spectrum from the original will largely remove the contributions from the broad lines. This provides a means of baseline correction.

A tomographic imaging plane, perpendicular to the ground, the coronal plane separates the anterior from the posterior part (the front from the back).

(MRI-CA, MRCA) The noninvasive imaging of the coronary arteries using magnetic resonance imaging of the heart.
For cardiac MRI-CA, high performance machines are necessary with minimum 40mT/m and 300μsec slew rate.
2D and 3D acquisition are used for fast gradient echo sequences with techniques for minimizing cardiac and respiratory motion and suppressing the high signal of pericardial fat. The optimal sequences seem to be trueFISP, Balanced FFE or FIESTA with SMASH and SENSE techniques. Respiratory motion is minimized for 3D acquisitions by using respiratory gating, especially using navigator echoes (Navigator Technique) to track diaphragmatic and cardiac movement. Optimization of MR technique can provide mapping of long segments of the coronary arteries.
Blood pool agents are being applied to improve the reliability of coronary MR angiography. The major current clinical indication is the identification of coronary artery anomalies because the diagnostic accuracy's for identifying haemodynamically significant stenoses are variable depending of the image quality.

See also Magnetic Resonance Angiography, and Cardiac MRI.

(MRI-CA) Coronary angiography with dobutamine stress tagging (MR images are taken after the heart has been stressed by using a medication called dobutamine). Investigational noninvasive imaging as a diagnostic tool for evaluating stenosis, anatomy and flow effects in coronary arteries with dobutamine stress.

For Ultrasound Imaging (USI) see Stress Echocardiogram at Medical-Ultrasound-Imaging.com.

The characteristic time between significant fluctuations in the local magnetic field experienced by a spin due to molecular motions. For values of the correlation time such that the magnetic field as a function of time has large Fourier components near the resonance frequency, the T1 relaxation time will be shortened.