Tc-99m depreotide SPECT/CT for lymph node staging of non-small-cell lung cancer.

OBJECTIVE: To investigate the potential role of Tc-99m depreotide (Tc-DEPR) in the preoperative lymph node (N) staging of non-small-cell lung cancer (NSCLC). METHODS: Sixty-one patients with NSCLC at the potentially operable stage were enrolled and underwent scintigraphy before surgery (n=56) or mediastinoscopy (n=5). Imaging was performed with a hybrid single photon emission computed tomography/computed tomography (SPECT/CT) system. Depreotide uptake in N stations was evaluated visually and semi-quantitatively and compared to histology. Quantification was carried out in attenuation-corrected SPECT slices. Different sites of normal uptake were used as a reference for comparison with lesional uptake. Receiver operating characteristic analysis was employed to identify the most preferable reference area and the cut-off best discriminating disease-free from disease-involved lymph nodes. RESULTS: With reference to 53 Ν1 hilar and 147 Ν2/Ν3 sampled stations, sensitivity of scintigraphy by visual interpretation was 100 and 94%, specificity 43 and 59% and accuracy 55 and 67%, respectively. No patient was down-staged, but 52% were incorrectly up-staged and 44% were misclassified as inoperable. Compared to scintigraphy, preoperative contrast-enhanced diagnostic CT demonstrated lower sensitivity (36% for hilar and 73% for N2/N3 stations), higher specificity (79 and 75%) and similar accuracy (70 and 75%). Regarding the ultimate N-stage and the prediction of surgical disease, diagnostic CT was wrong in 51 and 34% of cases. Dichotomy of quantitative scintigraphic data by the use of certain N-to-spine ratio cut-offs resulted in a significant increase of specificity (76% for hilar and 89% for N2/N3 stations), while sensitivity remained high (82% in both circumstances) and accuracy for Ν2/Ν3 stations was substantially improved (88%). By this quantitative approach, misclassifications as to the N-stage and patient operability (25 and 16%) were considerably less than that of visual Tc-DEPR and diagnostic CT interpretations. CONCLUSION: Tc-99m depreotide SPECT/CT seems to have a role in the N-staging of NSCLC, mainly because of its high sensitivity and negative predictive value. Quantification of uptake can improve specificity, at a low cost of sensitivity. If F-18 fluoro-deoxyglucose positron emission tomography is not available, this method may be used as a surrogate to conventional staging modalities.

Assessment of a new immunocytochemical technique in HbF-cell counting by a novel objective evaluation method.

A recently developed immunocytochemical technique in HbF-cell counting was assessed by an objective evaluation method. The basic principle of this method is the preparation of aliquots with predetermined HbF-cell (target) values. These aliquots serve as control samples to standardize the HbF-cell measurements by the new immunocytochemical technique, which uses the StreptABComplex/AP staining procedure (SAP) and visualization under white light. Immunofluorescence optical counts (IF) were performed in parallel with the new technique. A trend of inaccuracy was observed in low target values for both methods. As the level of target values increased, deviations became insignificant (relative accuracy < 8%) with SAP having slightly better results. Linear regression data of the estimated %HbF-cell rates by the two methods versus the target values were very satisfactory for both methods with SAP being slightly better. SAP seems to provide an accurate and reliable alternative for HbF-cell estimation comparable with the classical IF optical count.