RADIONUCLIDE IMAGING Pitfalls in the Diagnosis of Acute Osteomyelitis by Bone Scan

Two patients with acute osteomyelitis had technetium 99m methylene di-phosphonate bone images that were misinterpreted. A review of six prospective evaluations of technetium scanning in the diagnosis of acute osteomyelitis shows that bone image interpretation may be misleading in five to seven per cent of pediatric patients. Definitive diagnostic procedures and management should not be delayed until a positive bone scan is obtained, if the clinical findings are persuasive. RADIOGRAPHIC bony changes in acute hematogenous osteomyehtis are not usually apparent until 10 to 14 days after the onset of clinical disease; consequently, radiographs are seldom diagnostic in early osteomyelitis. Recently the technique ofradioisotope scan-ning has become popular as an aid in the early diagnosis of skeletal infection. We report two patients with osteomyelitis, in whom the bone scan interpretation, was misleading and have reviewed the literature for similar experiences. Methods. ’ B.... ’.. ’ ’ The bone images were performed after in- / jecting a dose of 200 pcilkg of technetium 99m methylene diphosphonate, Imaging of the appropriate regions was obtained at 5 min-utes. and again between 2-3 hours after in-~~~~i~~ ~ ~i~~’~~~~~~: ~~:~~~~ii~~i~ ~ ~~~~~~ ~ (large:, field of view Dynacamera). In case 1, the en-tire skeleton was also imaged. Case Reports Case 1. A 4py~ar-r~ld white boy with congenital ~-~e~akarocy~tic ‘ thrombe~c;vt~p~r~ia and recurrent neutropenia, was admitted to the hospital with a 2-~l~y history of fever and pain in his left ankle and cal£‘. There had been no trauma, and the pa-tient was not on antimicrobial therapy. 4’Jn physical examination he had a temperature of ~8.~ ~ and a. render indurated swelling of the proximai left calf. ~~rr~~~~~bir ~ was lt~. ~ g/dLand.thc white blood cell count (WBC) was 4300/cu mm with 5 % polymorpho