Virtual CT sonographically guided biopsy of a retroperitoneal mass in a patient with Erdheim-Chester disease.

Image fusion between sonography and CT allows real-time synchronization of CT multiplanar reconstructed images with the corresponding sonographic images. This technique has mainly been used in liver imaging. We report the use of image fusion to target and successfully guide the percutaneous biopsy of a retroperitoneal a mass. This technique represents a promising tool in abdominal imaging, and it should be considered for the biopsy of lesions that are difficult to approach with conventional imaging guidance techniques.