Ventilation/Perfusion SPECT - A New Challenge for Detection of Pulmonary Embolism. Can Multi Detector Computed Tomography Replace Lung Scintigraphy?

ventilation/perfusion scintigraphy (V/P-SCAN) was the procedure of choice for studying patients with suspected pulmonary embolism (PE) until the prospective evaluation of V/P imaging in the study known as PIOPED I revealed high number of non diagnostic findings. This has challenged development of computed tomography (CT) during 1990s. Since beginning of 2000, multidetector CT (MDCT) is widely applied and has become the most commonly used technique in patients with suspected PE. The current MDCT have very advanced technology and have improved ability to detect small emboli. Unfortunately, results of the most advanced MDCT are still compared with V/P-SCAN results performed in PIOPED I 20 years ago. However V/P-SCAN has further developed. Tomographic technique V/P-SPECT is taking over V/P-PLANAR. Probabilistic criteria are replaced by holistic criteria for interpretation, taking lessons learned from PIOPED I. Discussion is focused on diagnostic value for MDCT and V/P-SPECT. MDCT and V/P-SPECT are both indispensible imaging techniques to study patients with suspected PE. However, when available, V/P-SPECT should be the preferred method for diagnosis of PE, primarily due to the lower radiation exposure and applicability to all patients. Therefore it is our duty to make V/P-SPECT generally more available, to use holistic interpretation knowledge and to communicate daily with the clinicians, so that the best technique is used in all patients. In conclusion MDCT cannot replace V/P-SPECT. MDCT and V/P-SPECT are complementary rather the competitive!