Planar fusion: A PICTORIAL REVIEW.

摘要

Image fusion of SPECT and PET data with CT and MRI has been shown to improve diagnostic accuracy in a variety of clinical circumstances. While the use of SPECT/CT and PET/CT image fusion has been well documented in the literature, there has been limited documentation of the role of planar image fusion. This brief pictorial review provides case examples where planar fusion between bone scintigraphy and xray has been useful. Introduction Nuclear scintigraphy using single photon emission computed tomography (SPECT) provides functional information that is a valuable tool in the diagnosis of many diseases but is limited, on occasion, by less than ideal anatomic localization (1). Image fusion is a process of data superimposition using multiple image types; typically computed tomography (CT) or magnetic resonance imaging (MRI) for anatomic data superimposed with SPECT or positron emission tomography (PET) for functional data (1). Image fusion of SPECT and PET data to CT in particular has been shown to improve diagnostic accuracy in many clinical circumstances (2). While the use of SPECT/CT (3-5) and PET/CT (6-8) image fusion has been well documented in the literature, there has been limited documentation of the role of planar image fusion. Zuckier and Koncicki (9) reported using planar image fusion between planar scintigraphic and photographic images to better localize the position of focal radiopharmaceutical accumulation in low background images. More recently, fusion of planar scintigraphy to photographs was reported to offer more as a promotional tool than as a tool to improve diagnostic certainty (10). None the less, fusion of scintigraphy to photographs might benefit research studies that involve imaging of non human subjects where anatomy may be foreign to nuclear medicine experts (e.g. plant and animal studies). Zuckier and Koncicki (9) also reported using planar image fusion between orthopedic xrays and photographic images. Fusion of scintigraphy with photographs is limited by the ‘pin hole’ effect causing misalignment (10). Case Examples A more useful application of planar fusion would be fusing orthopedic xrays with bone scintigraphy. Despite the apparent transparency of benefits, planar fusion between xray and bone scan has only once been reported in the literature (10). Combining the high spatial resolution of xrays with the physiologically sensitive bone scan assist in overcoming the limitations of each. This brief pictorial review presents case examples (figures 1 to 8) where planar fusion between bone scintigraphy and xray has been useful.