The diagnostic services provided by Performance Horse Doc Veterinary Services are focused on dealing with medical and surgical conditions that compromise sport horse performance. The categories of diagnostic procedures include radiology, endoscopy, ultrasound, and gastroscopy. The majority of cases seen by PHD veterinary services and Dr. Porter involve conditions which result in some degree of lameness. These types of cases require a thorough lameness exam followed by diagnostic nerve blocks and the appropriate imaging. The imaging may involve digital radiography and/or digital ultrasound. PHD veterinary services use "real-time" digital x-rays and ultrasound to accurately diagnose the cause of the lameness. In some cases, "poor" performance may not be associated with lameness but rather due to respiratory disease, cardio-pulmonary disease, or metabolic disease. In these types of cases, Dr. Porter combines his specialty training in large animal internal medicine with diagnostic tools such as gastroscopy, endoscopy, ultrasound, and radiology to discern the cause of the poor performance.