Discordance between MRI and bone scan findings in a child with acute complicated osteomyelitis: scintigraphic features that contribute to the early diagnosis.

Early diagnosis and prompt treatment of acute osteomyelitis are of paramount importance in children because they can prevent irreversible bone damage. Magnetic resonance imaging (MRI) with its superior spatial resolution and lack of ionizing radiation is routinely preferred over bone scan for this purpose. Increased blood flow, hyperemia and focally increased tracer uptake shown by "three phase" bone scan are the typical scintigraphic findings of acute osteomyelitis. In addition, diffuse uptake along the shaft of long bones and focal "cold" lesions are two special features that may be highly suggestive of infective periostitis, soft tissue sepsis and subperiosteal abscess formation, due to the loose attachment of periosteum to bone during childhood. We present a case of complicated osteomyelitis in a child with inconclusive MRI correctly diagnosed on the basis of these special scintigraphic findings resulting in treatment change from double i.v. Vancomycin--Ceftriaxone scheme to surgical intervention.

Protocolo combinado de 99mTc-Ciprofloxacina y 99mTc-MDP en el diagnóstico de osteomielitis y prótesis articular infectada / 99mTc-ciprofloxacin/99mTc-MDP combined protocol in the diagnosis of osteomyelitis and infected joint prosthesis

Introducción. El centellograma óseo con 99mTc-MDP es una técnica útil en el diagnóstico de osteomielitis, sin embargo, presenta especificidad limitada en presencia de patología ósea previa (osteomielitis complicada). La 99mTc-ciprofloxacina es uno de los radiofármacos más difundidos para la detección de infecciones óseas, aunque persisten controversias sobre su rendimiento diagnóstico. Objetivo. Determinar el valor clínico del protocolo combinado de centellograma con 99mTc-ciprofloxacina y 99mTc-MDP en el diagnóstico de osteomielitis complicada y prótesis articular infectada. Materiales y métodos 37 pacientes con sospecha clínica de osteomielitis complicada o prótesis infectada fueron estudiados mediante centellograma con 99mTc-ciprofloxacina y 99mTc-MDP. 26/37 pacientes presentaban fractura previa, 7 prótesis de rodilla y 4 prótesis de cadera. En todos ellos se realizó seguimiento clínico y bacteriológico. Resultados. El método presentó sensibilidad de 94 por ciento, especificidad de 79 por ciento, valor predictivo positivo de 81 por ciento y valor predictivo negativo de 94 por ciento, con una exactitud de 86 por ciento. Conclusiones. El protocolo combinado de 99mTc-ciprofloxacina y 99mTc-MDP presenta elevado rendimiento para el diagnóstico de osteomielitis complicada y prótesis articular infectada.

Introduction. Bone scintigraphy with 99mTc-MDP is a useful technique in the diagnosis of osteomyelitis, however, has limited specificity in the presence of previous bone pathology (complicated osteomyelitis). 99mTc-ciprofloxacin is one of the most widely used radiotracers for the detection of bone infection, although controversies persist on its diagnostic performance. Objective To determine the clinical value of 99mTc-ciprofloxacin/99mTc-MDP combined protocol in the diagnosis of complicated osteomyelitis and infected joint prosthesis. Materials and methods 37 patients with clinically suspected complicated osteomyelitis or infected prosthesis were studied with 99mTc-ciprofloxacin and 99mTc-MDP scintigraphy. 26/37 patients had previous fractures, 7 had knee replacements and 4 had hip replacements. All of the patients underwent clinical and bacteriological follow-up. Results. The method presented sensitivity of 94 percent, 79 percent specificity, 81 percent positive predictive value and 94 percent negative predictive value, with an accuracy of 86 percent. Conclusions. The combined protocol using 99mTc-ciprofloxacin/99mTc-MDP showed high diagnostic performance in complicated osteomyelitis and infected joint prosthesis.