InfraMation 2007 Proceedings ITC 121A 2007-05-24 3D MRI/IR Imaging Fusion: A New Medically Useful Computer Tool Marcos L. Brioschi, M.D., Ph.D, Ionildo Sanches, M.Sc., Fabricius Traple, M.S. InfraredMed® – Infrared Medical Diagnosis ABSTRACT The measurement of temperature variation along the surface of the body provided by infrared imaging (IR) is becoming a valuable auxiliary tool for the early detection of many diseases in medicine. However, IR is essentially a 2D technique and its image does not provide useful anatomical information associated with it. However, multimodal image registration and fusion may overcome this difficulty and provide additional information for diagnosis purposes. In this paper, a new method of registering and merging 2D IR and 3D MRI is presented. Registration of the images acquired from the two modalities is necessary since they are acquired with different image systems. First, the body volume of interest is scanned by a MRI system and a set of 2D IR of it at orthogonal angles is acquired. Next, it is necessary to register these two different sets of images. This is done by creating 2D MRI projections from the reconstructed 3D MRI volume and registering it with the IR. Once registered, the IR image is then projected over the 3D MRI. The program developed to assess the proposed method to combine MRI and IR resulted in a new tool for fusing two different image modalities, which can help medical doctors. INTRODUCTION Infrared imaging (IR), or simply thermography, is an extremely sensitive diagnostic test that measures and records surface temperature and natural heat distribution in the body. The applications of thermography in medicine for the diagnosis of various disease processes have expanded over the past decade coincident with technological advances in thermal imaging 1-4, 14-15 . The medical use of IR is not new. However, with the recently improved sensitivity (around 0.02 degree Celsius) of the new generation of infrared sensors, IR is beginning to be a safe, efficient and reliable method for the study of some human diseases 1-3 . A main advantage of IR as an auxiliary tool in medical diagnosis includes its relative low cost compared to other medical technologies. This noninvasive technique is ideal as a diagnostic method since it is completely harmless, without damaging radiation, and is devoid of needles or other noxious devices. Medical IR makes use of the long wave infrared thermal radiation energy emitted by the skin body. Nonetheless, this technique has some limitations and thus it is still not used systematically for clinical diagnosis worldwide. IR is currently used to assess diseases such as breast and thyroid tumors, cerebral and peripheral vascular disease, rheumatic disease, musculoskeletal disorders, inflammations, and also during cardiac bypass surgery 1-4, 14-15 . In the particular case of Peripheral Vascular Disease (PVD) – a disease that compromises main blood supply to inferior limbs – IR is used to evaluate the extent of the damage to the limb 5 . PVD is characterized by constriction or occlusion of the main arteries that supply blood to the limbs. If not diagnosed in time, PVD can lead to partial or total amputation of the limbs, mainly in the lower body. In these cases, the preservation of the knee joint in patients submitted to amputation due to critical ischemia is associated to a better rehabilitation, mobility and quality-of-life post surgery. Unfortunately, due to the absence of a safe, precise, and low-cost method to evaluate the level of local microcirculation compromise, many surgeons still prefer to amputate above the knee joint as a safety procedure. An inadequate amputation of the affected area leads to a difficult healing and to a high incidence of re-amputation. McCollum et al. 6 have demonstrated that it is possible to determine more accurately the level of amputation in ischemic limbs with the use of IR.