Differentiation of malignant and degenerative bone lesions using dexamethasone interventional 3- and 24-hour bone scintigraphy

Abstract

Seventy-seven adult patients with suspected skeletal metastases were divided into two groups. In group A (n = 30), following intravenous administration of 20 mCi (740 MBq) of technetium-99m methylene diphosphonate (99mTc-MDP), 3- and 24-h scintigraphy of bone lesions was performed. The 24/3 h lesion to bone background radiouptake ratio (RUR) was calculated for each lesion. In group B (n = 47), the same procedure was followed with dexamethasone intervention (10 mg in 24 h) following the 3-h acquisition. In group A, after determination of the critical point, malignant and degenerative bone lesions could be separated with a sensitivity, specificity and accuracy of 0.76, 0.72 and 0.73, respectively. The mean RUR of the malignant lesions was 1.20 +/- 0.23, and that of the benign lesions, 0.95 +/- 0.15. In group B cases, significantly increased sensitivity, specificity and accuracy of 0.87, 0.94 and 0.92, respectively, were found (P < 0.001). The mean RUR of the malignant lesions was 1.48 +/- 0.34, and that of degenerative lesions, 0.88 +/- 0.19. Dexamethasone interventional bone scintigraphy seems to be a new cost-effective method for differentiating malignant from degenerative bone lesions using the RUR.

Tc-99m Ciprofloxacin Scans for Detection of Tubercular Bone Infection

“…Studies using 4 and 24 hour bone imaging to increase the sensitivity of bone scans and using delayed imaging in Tc-99m MIBI scan to distinguish between benign or malignant thyroid nodules also suggested the usefulness of delayed imaging to improve the specificity of radionuclide scans. 20,21 When clinical trials of Tc-99m ciprofloxacin were conducted at our institute, it was found that the scans were positive in aseptic arthritis and other patients having aseptic inflammation. Delayed scans at 3 and 24 hours were done to determine if delayed imaging could be helpful to increase the specificity of Tc-99m ciprofloxacin scans.…”

Analysis of bone activity of jaws using scintigraphy on patients before, during and after treatment with IV bisphosphonates

“…Uptake in degenerative lesions either tends to maintain itself or decreases over this interval. This distinction enables the radiologist to recognize malignant disease[186]. Additionally, this study showed that the administration of dexamethasone between the three-and 24-hour scans enhanced the difference between three-and 24-hour uptakes by decreasing the uptake of radionuclide in the normal areas and benign lesions.…”

“…Eightyfive percent of malignant tumors were clearly demonstrated on the 99mTc-MIBI scans.Lung metastasis and lymph node involvement were also demonstrated on 99mTc-MIBI scans that did not appear on 99mTc-MDP bone scans. The authors concluded that 99mTc-MIBl cannot replace standard 99mTc-MDP bone scanning as an initial protocol for tumor scanning, but that important additional information seen on 99mTc-MIBI scans may complement standard bone scanning in selected cases[185].Bone scanning at three and 24 hours following radiopharmaceutical administration has been shown to enhance the differentiation of benign from malignant tumors by Bhatnagar et al in 1994[186]. The activity of lesions in both the three-and 24hour scans is quantitated and compared with the activity of normal bone.…”

“…Additionally, this study showed that the administration of dexamethasone between the three-and 24-hour scans enhanced the difference between three-and 24-hour uptakes by decreasing the uptake of radionuclide in the normal areas and benign lesions. The application of this medication therefore accentuated the difference between malignant tumors and their background areas[186].Recent reports have indicated the potential benefit of FDG (fluorine-labeled glucose) PET scanning to identify primary and recurrent head and neck tumors[187].Lapela and associates studied 15 patients with clinical or CT evidence of recurrence of head and neck cancer. Nine of these patients were suspected of having recurrent primary oral cancers.…”