Automated Software for PET/CT Image Registration to Avoid Unnecessary Invasive Cardiac Surgery

Computed tomography (CT) is used for the attenuation correction of positron emission tomography (PET) to enhance the efficiency of data acquisition process but due to the use of two different modalities chances of misalignment between PET and CT images are quite significant. There are multiple causes of this misalignment, the most important being the respiratory motion of the patient. The position of the heart in PET and CT can have a difference of up to 2 cm along the long axis of the body. If such a misaligned CT attenuation correction map is used for the PET reconstruction it will cause erroneous results by projecting the lungs attenuation parameters on the cardiac wall creating false areas of hypoperfusion which may be misinterpreted as myocardial ischemia or infarction and can lead to unnecessary invasive procedure like bypass or angioplasty. In this paper, an automated cardiac software alignment method is proposed to overcome this motion artifact. PET and CT heart geometries are aligned using efficient real time image processing techniques and results of this optimization procedure have been evaluated on 100 PET/CT cardiac data sets producing accurate cardiac alignment which eliminated PET/CT misregistration attenuation correction artifact.