Isotope bone imaging in suspected scaphoid trauma

Abstract

The unreliability of radiological examination in excluding or confirming a suspected scaphoid fracture after carpal trauma is a well-recognised diagnostic problem. This paper explores the role of isotope bone imaging (IBI) in the early identification of carpal bone injury. Abnormal generalized uptake of activity may be seen within the carpus, possibly as a consequence of diffuse soft tissue injury, particularly if imaging is performed within 48 hours of trauma. A focal area of increased uptake related to one carpal bone is suggestive of fracture though the part which ligamentous injury, localized periosteal reaction or incomplete cortical infarction may play in the production of such radionuclide appearances is uncertain. Ninety-nine patients with suspected recent scaphoid fracture but no demonstrable abnormality on radiological examination were subjected to IBI, using 555 MBq (15 mCi) of 99Tcm methylene diphosphonate. Abnormal focal increased uptake (AFIU) was found in 47 patients, this being localized to the scaphoid bone in 26. Of these 47 cases, 19 (42%) showed subsequent radiological evidence of fracture. The results of IBI, in our experience, can only be reliably interpreted if imaging is performed at least 48 hours after injury, though in cases of fracture AFIU may persist for several years. Using this technique, the possibility of fracture can be confidently excluded in that group of patients who show no AFIU. In selected cases of carpal trauma, IBI provides a satisfactory alternative means of identifying the presence and site of localized injury within the carpus and may be used to confidently exclude those patients with non-osseous symptomatology.

Management of suspected scaphoid fractures in accident and emergency departments – time for new guidelines

“…22 However, bone scintigraphy is expensive, and the question as to when to perform bone scintigraphy also remains controversial. 11,24,28 In our survey, only 10% of the A&E departments had direct access to bone scans. Most clinicians would repeat the radiographs even at second follow-up, and bone scanning is generally not considered until 3-4 weeks after initial injury.…”

Technetium-99m imaging of bone trauma: reduced sensitivity caused by hydrocortisone in rabbits

“…Sensitivity was influenced most at 48 hr after injury; the averages were 41 % in the high-dose group as compared with 95% for the control group. During the period of 1 to 3 weeks after the time of injury, mean sensitivities in the high-dose and control groups averaged 84% and 100%, sensitive at 2 to 3 days after injury [5][6][7]. However, our study shows that reliance on the bone scan in the presence of steroid therapy may be misleading.…”

Diagnosis of occult scaphoid fractures: a randomized, controlled trial comparing bone scans to radiographs for diagnosis

“…The study was powered to display a difference in days immobilized of 5. This translates to a 5-day work week and [12][13][14][15]17 ; thus, the sample size calculation was based on 10% scaphoid fractures in each group. We assumed that patients with a suspected scaphoid fracture did not have any other type of fracture.…”

“…If tenderness persists, radiographs are repeated to assess for a scaphoid fracture. Unfortunately, repeat radiographs are only 30% sensitive, [12][13][14][15] so the patient again returns for repeat radiographs after another 10 to 14 days or undergoes a three-phase bone scan. Radiographs or bone scans suggesting a scaphoid fracture result in a further 4 to 10 weeks of immobilization.…”