On SurgOnc Today®, Jeffrey J. Pelton, MD, and Randall P. Scheri, MD, discuss the use and efficiency of four-dimensional CT scanning in preoperatively localizing adenomas in patients with primary hyperparathyroidism prior to cervical exploration. The discussion includes: The anatomic body planes and the “fourth dimension” of CT scanning. How the 4D CT scan is performed and how this achieves localization of abnormal parathyroid glands. The role 4D CT scanning plays in the pre-operative work-up for primary hyperparathyroidism. What the surgeon wants to know from the radiologist on a 4D CT report. Potential risks and pitfalls in interpreting a 4D CT scan prior to proceeding with surgical exploration. Dr. Pelton and Dr. Scheri also discuss what the literature has reported on this subject, how they approach surgical exploration using the information and their own experiences with this test.