Volume Rendering-Based Phrenic Nerve/Pericardiophrenic Bundle Identification Using Cardiac Computed Tomography.

ANATOMY: Phrenic nerves descend anterior to the pulmonary hila, sandwiched between the pericardium and parietal pleura, thus running extrinsically to the heart and lungs.

PATHOLOGY: Phrenic nerve injury during catheter ablation or diaphragmatic stimulation during cardiac resynchronization therapy.

IMAGING CORRELATION: Conventional approach of preprocedural identification of the phrenic nerve includes slice-by-slice detection of the pericardiophrenic bundle using axial images. However, it is time-consuming with substantial uncertainty and difficulty in precise structural tracing in each axial plane. Three-dimensional visualization using a volume rendering technique has a distinct advantage for detecting fine structures and their anatomical course.

TREATMENT: Preprocedural identification of the 3-dimensional course of the phrenic nerve in relation to surrounding structures is useful in avoiding iatrogenic injury of the phrenic nerve or predicting diaphragmatic stimulation.

TAKE-HOME MESSAGE: Volume rendering reconstruction offers fast and easy 3-dimensional identification of the phrenic nerve and is even feasible without a contrast material.