Comparison of four methods for quantitative assessment of 99mTc-MDP SPECT in patients with suspected condylar hyperplasia. / Comparación de cuatro métodos de valoración cuantitativa de la SPECT con 99mTc-MDP en pacientes con sospecha clínica de hiperplasia condilar.

OBJECTIVE: To compare variability, reproducibility and repeatability of four quantitative evaluation methods to interpret the 99mTc-MDP SPECT reports in patients with clinically suspected unilateral condylar hyperplasia. METHOD: This was a descriptive observational study carried out with SPECT images of 38 patients with clinical and radiographic signs of unilateral condylar hyperplasia, and interpreted using four quantitative methods: 1) one image, variable-size region of interest (ROI); 2) one image, fixed-size ROI (1.76cm2), 3) five image variable-size ROI; 4) five image, fixed-size ROI (1.76cm2). Each of the images was reported simultaneously (but in an independent way) by two nuclear medicine experts, in both total radioactive counts as well as normalized counts to evaluate the reproducibility (inter-operator variability) and the repeatability (intra-operator variability). RESULTS: Higher reproducibility and repeatability were obtained in 5-image fixed-size ROI method (intra-class correlation coefficient: 0.979 [0.959; 0.989]). A high grade of diagnostic agreement (97.4%) was also attained in fixed methods (Kappa 0.940, p value: .000) from either total or normalized counts. There was no difference between fixed-size 1 vs 5 image methods. The methods based on variable-size ROI had a low grade of agreement (Kappa<0.20). More positive cases were identified using one image, ROI variable total counts (27 cases), but when the counts were normalized, they presented a lower number (5 cases). CONCLUSION: Five-image fixed-size ROI provides the best intra-operator and inter-operator reliability for the diagnosis of unilateral condylar hyperplasia. In the four methods using normalized counts fewer positive cases were detected (≥10%), unlike with total counts when more positive cases were found.

[Octreotide scintigraphy in thyroid orbitopathy]. / Gammagrafía con octreótido en la orbitopatía distiroidea.

INTRODUCTION: Graves' disease, which has an autoimmune basis, is associated with the infiltration of activated lymphocytes into the retrobulbar tissues of the eye. These activated lymphocytes express somatostatin receptors on their surface which mediate the inflammatory response. OBJECTIVE: To evaluate the efficiency of (111) In-Octreotide scintigraphy in the identification of orbital activity in Graves' disease and the usefulness of treatment with a somatostatin analogue, based on a pre-established protocol within the Nuclear Medicine Department. METHODS: We studied a group of eighteen patients with symptomatic Graves' ophthalmopathy of between two months and four years duration. We injected 6 mCi of (111) In-Octreotide parenterally, and performed scintigraphy four and twenty-four hours later. Four patients, all in the active phase, showed orbital somatostatin receptors, for which they were treated with lanreotide 60 mg every fifteen days for three months. Patients were reviewed after 3 months treatment with a further scintigraphy and clinical study. RESULTS: In our study all four treated patients had less than sixteen months of ophthalmopathy, and three responded well to the treatment. CONCLUSION: Scintigraphy with Octreotide is a useful procedure allowing identification of patients in the active phase of the ophthalmopathy who are likely to respond well to treatment with somatostatin analogues.

[Extraosseous accumulation of 99mTc-HMDP in knees with synovial effusion]. / Acúmulo extraóseo de 99mTc-HMDP en rodillas con derrame sinovial.

In the presence of extraosseous activity seen in the late phase of the bone scintigraphy (BS) localized in the distal femur of patients prior to radiation synovectomy, we decided to review the frequency of this finding in 20 patients (24 joints) and its relationship with scintigraphic and clinical parameters. Mild soft tissue accumulation was seen in the late phase of the BS in 14 out of 24 joints, without association between this finding and knee uptake in vascular blood pool and late phases of the BS. However, a significant association with synovial effusion was found, and patients with higher degree of effusion presented extraosseous activity more frequently. In conclusion, we think that soft tissue accumulation in the late phase of the BS is a sign of synovial effusion.