The present invention relates to an improved method of imaging cardiac neurotransmission in vivo in a human subject using adrenergic imaging agents. The method comprises obtaining two separate images with the same adrenergic imaging agent. One of the images is obtained in conjunction with the administration of a compound known to interfere with the uptake of the particular imaging agent in question. Comparison of the two images enables additional information to be obtained in relation to the status of cardiac neurotransmission in said subject compared with imaging with adrenergic imaging agent alone. The invention also provides a method of imaging cardiac neurotransmission in a human subject in vivo wherein a single image is obtained using an adrenergic imaging agent in conjunction with the administration of a non-pharmaceutical dose of an agent known to interfere with the uptake of the imaging agent. The invention furthermore provides a method of operating an imaging apparatus, a second medical use of an adrenergic imaging agent as well as a kit suitable for carrying out the methods of the invention.