A critical appraisal of pinhole scintigraphy of the ankle and foot

BACKGROUND: Scintigraphy is an established imaging technique for injuries of the ankle and foot that are not apparent on plain radiographs. The scintigraphic technique has varied, with planar and pinhole images being used. MATERIALS AND METHODS: The incremental value of pinhole scintigraphy over planar imaging was studied in 16 patients with established diagnoses. Inter-reporter reproducibility was also measured. RESULTS: Pinhole scintigraphy improved the diagnostic specificity in nearly one half of the patients (48%). It did not contribute substantial information in 46% and led to confusion in the diagnosis of one patient. Inter-reporter agreement was good, with a kappa value of 0.78. Diagnoses varied from fractures of the talar dome to avulsion fractures of the malleoli and impingement syndromes. CONCLUSIONS: Pinhole images add a significant incremental value to planar scintigraphy of the foot and ankle. Although this had been perceived intuitively in the past, it has not been critically evaluated. The technique has good inter-reporter agreement.