The diagnostic value of (99m)Tc-IgG scintigraphy in the diabetic foot and comparison with (99m)Tc-MDP scintigraphy.

UNLABELLED: Diabetic foot infection is the most common etiology of nontraumatic amputation of the lower extremities, and early diagnosis is of great importance in its management. The aim of this prospective study was to evaluate the strength of (99m)Tc-IgG scintigraphy in diagnosis of osteomyelitis of the diabetic foot and to compare (99m)Tc-IgG scintigraphy with (99m)Tc-methylene diphosphonate (MDP) scintigraphy. METHODS: A prospective university hospital-based study was performed over 24 mo. Eighteen patients with type II diabetes and foot ulcers (15 men and 3 women; age range, 45-80 y) were referred for imaging because of clinically suspected osteomyelitis. Early (5-h) and late (24-h) (99m)Tc-IgG scanning and 3-phase skeletal scintigraphy were completed for all patients at a 3- to 4-d interval. Regions of interest over the involved bony sites and the contralateral normal sites were drawn, and the abnormal-to-normal ratios were acquired for both (99m)Tc-IgG and (99m)Tc-MDP studies. RESULTS: From a total of 23 lesions, we observed 10 sites of osteomyelitis, 10 sites of cellulitis, and 3 sites of aseptic inflammation confirmed by MRI, clinical presentation, histopathologic examination, and follow-up evaluation as a gold standard. Both (99m)Tc-IgG and (99m)Tc-MDP scanning showed excellent sensitivity for diagnosis of osteomyelitis, but the specificity was significantly lower (69.2% and 53.8%, respectively). Sensitivity, specificity, and accuracy in the diagnosis of osteomyelitis were, respectively, 100%, 53.8%, 73.9% for (99m)Tc-MDP scanning; 100%, 69.2%, 82.6% for 5-h (99m)Tc-IgG scanning; and 60%, 76.9%, 69.5% for 24-h (99m)Tc-IgG scanning. There was no significant difference between the semiquantitative indices of 5-h and 24-h (99m)Tc-IgG scanning for inflammation, cellulitis, and osteomyelitis. CONCLUSION: Although both (99m)Tc-IgG and (99m)Tc-MDP scintigraphy have high sensitivity for the diagnosis of osteomyelitis, the specificity of these studies is poor. For (99m)Tc-IgG scintigraphy, 5-h images appear to be adequate, and there is little benefit to performing additional imaging at 24 h.

The association of dipyridamole side effects with hemodynamic parameters, ECG findings, and scintigraphy outcomes.

UNLABELLED: Dipyridamole has extensively been administered as a substitute for physical activity in cardiovascular assessment. The aim of this study was to evaluate the association of dipyridamole side effects with hemodynamic oscillations, scanning results, and electrocardiography (ECG) findings. METHODS: Overall, 590 patients referred to the nuclear medicine center for myocardial perfusion imaging were evaluated for adverse dipyridamole effects concurrent with a low level of exercise. Before and during dipyridamole infusion, the patients' vital signs, electrocardiogram, heart rate, systolic blood pressure, and diastolic blood pressure were monitored; all patients underwent stress-rest (99m)Tc-sestamibi gated SPECT using a 2-d protocol. RESULTS: Eighty-eight patients (14.9%) experienced at least one side effect during dipyridamole infusion, and abnormal ECG and scan results were observed in 32.4% and 48.6% of patients, respectively. We observed a positive correlation between a higher incidence of chest discomfort, headache, and dyspnea and abnormalities on ECG and myocardial perfusion imaging. In addition, these 3 side effects were also associated with a higher postinfusion heart rate, lower preinfusion systolic blood pressure, and lower postinfusion diastolic blood pressure. There were significant differences between pre- and postinfusion heart rate, preinfusion systolic blood pressure, and postinfusion diastolic blood pressure among patients with or without side effects, whereas no significant difference was observed in any of the hemodynamic parameters between patients with normal and abnormal ECG results or myocardial perfusion imaging results. CONCLUSION: This study demonstrated a correlation between hemodynamic variables and side effects but not with imaging findings or ECG findings.

Chromosome aberrations after high-dose 131I and 99mTc-MIBI administration using a micronucleus assay.

OBJECTIVE: We evaluated the potential detrimental cytogenetic effects of Tc-methoxyisobutyl isonitrile (MIBI) and I on patients who were exposed to the radiopharmaceutics for cardiac imaging or thyroid cancer therapy, respectively. METHODS: Mononuclear leukocytes were isolated both before and after radiopharmaceutical administration and subsequently cultured. Micronuclei frequency was then assessed and microscopic evaluation of apoptosis was conducted. RESULTS: Small statistically insignificant augmentation in the percentage of micronuclei from 10.9+/-3.8 to 11.3+/-2.4% was observed in the Tc-MIBI group. In contrast, I elicited a notable augmentation of micronuclei from 6.3+/-2.2 to 9.6+/-3.1 at 3.7 GBq, and 6+/-1.5 to 9.2+/-2.7 at 5.55 GBq (P<0.05). CONCLUSION: Our results showed that there were no remarkable alterations either in the micronuclei incidence or in the percentage of apoptotic lymphocytes after in-vivo exposure to radiopharmaceutical imaging, which provides evidence to reduce the growing concern about the safety issue of cardiac imaging with Tc-MIBI, whereas the deleterious effects of I must be considered when it is applied to thyroid cancer treatment.