A method of guiding a cardiac treatment using a functional imaging modality, comprising: providing functional imaging modality data from a functional imaging modality which images an intrabody volume of a patient containing a heart, the patient having been injected with an imaging agent having a nervous tissue uptake by an autonomic nervous system (ANS) of the heart, the ANS comprising at least one GP; locating the at least one GP innervating the heart based on the functional imaging modality data; and providing the located at least one GP.