Cold-hot mismatch between Tc-99m HMPAO-labeled leukocytes and Tc-99m ciprofloxacin in axial skeleton infections - A report of three cases

Radiolabeled leukocyte scintigraphy is a well-established technique for the diagnosis of inflammation and infection with a typical presentation of a h ot spot within the abnormal areas. However, in some cases of osteomyelitis of the axial skeleton, a cold defect pattern has been described, Tc-99m cip rofloxacin is a new agent claimed to be specific for imaging sites containi ng viable bacteria. In this report, we present three cases of proved bacter ial infection of the axial skeleton with a mismatch pattern between Tc-99m ciprofloxin and tagged leukocytes, Although Tc-99m-labeled leukocyte scanni ng showed a cold defect, probably caused by bone marrow replacement, the Tc -99m ciprofloxacin consecutively revealed a hot spot at the site of infecti on, These data suggest that Tc-99m ciprofloxacin should be a better agent t han radiolabeled leukocytes for detecting osteomyelitis of the axial skelet on.