Posttherapy technetium-99m pentavalent dimercaptosuccinic acid brain single-photon emission computed tomography/computed tomography: diagnostic and prognostic values in patients with glioma.

PURPOSE: To assess the value of posttherapy 99mTc-pentavalent dimercaptosuccinic acid (DMSA-V) brain SPECT/CT in patients with brain glioma. METHODS: Patients with pathologically or radiologically proven glioma were prospectively enrolled in this study. 99mTc-DMSA-V brain SPECT/CT images were acquired at 120-180 min after i.v. injection of 555-740 MBq of 99mTc-DMSA-V. Three nuclear medicine physicians blindly interpreted the scans visually as positive or negative for residual/recurrent disease. Agreement between two or more readers was considered a consensus. The composite reference standard was considered based on subsequent clinical/neuroimaging follow-up or histopathology whenever available. Overall survival (OS) was calculated from the date of initial diagnosis till the death or the date of last follow-up. RESULTS: Thirty-four patients (18 males and 16 females; mean age 37.7 ± 16 years) were enrolled in this study. Interreader agreement between the readers ranged from 0.71 to 0.82. Based on the composite reference standard, residual/recurrent disease was confirmed in 16 patients, whereas 18 patients were negative for disease. Consensus reading of 99mTc-DMSA-V SPECT/CT accurately diagnosed 13 true positive (sensitivity 81%) and 17 true negative scans (specificity 94%). After a median follow-up of 22.9 months, 7/14 patients with positive 99mTc-DMSA-V SPECT/CT brain readings died compared to 4/20 with negative readings. The median survival was 24.1 months for the positive group and was not reached for the negative group. CONCLUSION: Posttherapy brain SPECT/CT scanning with 99mTc-DMSA-V is a noninvasive, reliable, and specific tool for evaluation of patients with brain glioma after definitive therapy. Scan positivity was associated with poor OS.

Correlation between semiquantitative and volumetric 18F-FDG PET/computed tomography parameters and Ki-67 expression in breast cancer.

OBJECTIVES: To evaluate the relationship between semiquantitative and volumetric parameters on 18F-FDG PET/computed tomography (CT), including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), tumor to liver ratio (TLR) and tumor to mediastinum ratio (TMR) with the level of Ki-67 expression in breast cancer. PATIENT AND METHODS: We retrospectively reviewed 105 female patients with newly diagnosed breast cancer who underwent baseline 18F-FDG PET/CT and had immunohistochemical staining to determine the level of Ki-67 expression. The following PET parameters were measured (SUVmax, SUVmean, MTV, TLG, TLR and TMR) and correlated with level of Ki-67 expression. RESULTS: Significant moderate positive correlations were found between the PET parameters (primary SUVmax, SUVmean, TLG, TLR and TMR) and level of Ki-67 expression. The primary SUVmax had the highest correlation coefficient (r = 0.461) followed by TMR (r = 0.455) and P value of <0.001 for both. In ROC analysis, primary SUVmax had the largest area under the curve (0.806, P = 0.0001), with sensitivity of 76.5 % and specificity of 75% for prediction of high Ki-67 level. In univariate analysis, all PET parameters, patient age, tumor grade, molecular subtype, estrogen receptor and progesterone receptor status were significantly associated with Ki-67 level. In multivariate regression analysis, only tumor grade [odds ratio (OR) = 20.460, 95% confidence interval (CI): 11.360-29.559, P = <0.0001], molecular subtype (OR = -21.894, 95% CI: -37.921 to -5.866, P = 0.008), SUVmax (OR = 2.299, 95% CI: 0.703-3.895, P = 0.005) and TLR (OR = -4.908, 95% CI: -9.476 to -0.340, P = 0.035) were found to be the strongest independent predictor factors for the level of Ki-67 expression and hence proliferative activity of malignant cells in breast cancer. CONCLUSION: The semiquantitative parameters and volumetric 18F-FDG PET/CT parameter, that is, TLG correlated well with proliferation marker Ki-67 in breast cancer. 18F-FDG PET/CT imaging can be used as a useful noninvasive diagnostic tool in imaging cellular proliferation and hence may substitute for in vitro testing of molecular markers in the diagnoses and staging of breast cancer.