Two-dimensional fusion imaging of planar bone scintigraphy and radiographs in patients with clinical scaphoid fracture: an imaging study

BACKGROUND: Although magnetic resonance imaging (MRI) is now considered the gold standard in second-line imaging of patients with suspected scaphoid fracture and negative radiographs, bone scintigraphy can be used in patients with pacemakers, metallic implants, or other contraindications to MRI. Bone scintigraphy is highly sensitive for the detection of fractures, but exact localization of scintigraphic lesions may be difficult and can negatively affect diagnostic accuracy. PURPOSE: To investigate the influence of image fusion of planar bone scintigraphy and radiographs on image interpretation in patients with suspected scaphoid fracture. MATERIAL AND METHODS: In 24 consecutive patients with suspected scaphoid fracture, a standard planar bone scintigraphy of both hands was supplemented with fusion imaging of the injured wrist. Standard and fusion images were evaluated independently by three experienced nuclear medicine physicians. In addition to the diagnosis, the degree of diagnostic confidence was scored in each case. RESULTS: The addition of fusion images changed the interpretation of each of the three observers in seven, four, and two cases, respectively, reducing the number of positive interpretations of two of the observers from 11 and nine cases to six and seven cases, respectively. The degree of diagnostic confidence increased significantly in two observers, and interobserver agreement increased in all three pairs of observers from 0.83, 0.57, and 0.73 to 0.89, 0.8, and 0.9, respectively. CONCLUSION: Image fusion of planar bone scintigrams and radiographs has a significant influence on image interpretation and increases both diagnostic confidence and interobserver agreement.