Radiology, Vol 163, 725-726, Copyright © 1987 by Radiological Society of North America
Osteomyelitis and soft-tissue infection: differential diagnosis with 24 hour/4 hour ratio of Tc-99m MDP uptake
O Israel, S Gips, J Jerushalmi, A Frenkel and D Front
The lesion-to-nonlesion 24 hour/4 hour ratio of technetium-99m methylene
diphosphonate (MDP) uptake was used to distinguish osteomyelitis from
increased bone uptake caused by adjacent soft-tissue infection. In a
prospective study, this ratio was measured in 38 patients with 41 sites of
increased uptake that were suspected to be osteomyelitis. The mean ratio
was 1.18 +/- 0.18 in patients with proved osteomyelitis, which was
significantly higher (P less than .001) than that in patients with
increased uptake resulting from soft-tissue infection (0.98 +/- 0.05). On
the basis of a receiver operating characteristic curve, a ratio of 1.06 was
selected as the cutoff for differentiating osteomyelitis from soft-tissue
infection. This method resulted in a sensitivity of 82%, a specificity of
92%, and an accuracy of 85%, and it appears to be more reliable than three-
and four-phase scintigraphy, which are subjective and nonquantitative
techniques.
