Evaluation of Salivary Gland Dysfunction Using Salivary Gland Scintigraphy in Sjögren's Syndrome Patients and in Thyroid Cancer Patients after Radioactive Iodine Therapy.

PURPOSE: Salivary gland scintigraphy (SGS) provides an objective means of diagnosing salivary gland dysfunction in Sjögren's syndrome (SS) patients and in thyroid cancer patients after radioactive iodine (RAI) therapy. In the present study, SGS was performed in SS patients and in thyroid cancer patients post-RAI, and scintigraphic parameters were compared. METHODS: Twenty-eight SS patients (males:females = 1:27, age 53.3 ± 11.9 years), 28 controls (males:females = 3:25, age 54.1 ± 10.1 years), and 92 thyroid cancer patients (males:females = 28:64, age 46.2 ± 12.9) who had undergone a session of high-dose RAI therapy (mean dose, 5.2 ± 1.5 GBq) were included. SGS was performed using Tc-99m pertechnetate (925 MBq). Scintigraphic parameters (parotid uptake ratio PU, submandibular uptake ratio SU, percentage parotid excretion %PE, and percentage submandibular excretion %SE) were measured and compared for SS, thyroid cancer post-RAI, and control patients. RESULTS: PU, SU, %SE, and %PE were all significantly lower in SS than in post-RAI thyroid cancer or control patients (p < 0.05), whereas only %PE was significantly lower in post-RAI thyroid cancer patients than in controls (p < 0.05). SU and %SE were found to be correlated with the unstimulated whole salivary flow rate. CONCLUSION: Scintigraphic parameters derived from SGS can play a crucial role in the detection of salivary gland dysfunction in SS patients and in post-RAI thyroid cancer patients.

Real-time in vivo monitoring of viable stem cells implanted on biocompatible scaffolds.

PURPOSE: Three-dimensional fibrous scaffolds provide an environment that enhances transplanted stem cell survival in vivo and facilitates imaging their localization, viability, and growth in vivo. To assess transplanted stem cell viability on biocompatible polymer scaffolds in vivo, we developed in vivo imaging systems for evaluation of implanted viable neural stem cells (NSC) and mesenchymal stem cells (MSC) on scaffolds using luciferase or sodium/iodide symporter (NIS) genes. METHODS: Firefly luciferase stably expressing-C6 cell was established (C6-Fluc). The human neural stem cell, F3, was infected with adenoviral vector carrying luciferase gene (F3-Fluc) and MSC expressing NIS controlled by ubiquitin C promoter using lentiviral vector was established by treating blasticidine for 2 weeks (MSC-NIS). Chitosan and poly L-lactic acid (PLLA) scaffolds were used for in vivo image. In vivo expression of luciferase and human NIS was examined by bioluminescence image or (99m)Tc-pertechnetate gamma camera image, respectively. The cell/scaffold complex was implanted into subcutaneous or abdominal area of BALB/C nude mouse. For quantitative evaluation of cell viability, regions of interest were drawn on (99m)Tc-pertechnetate scintigraphy by manual. RESULTS: The gradual increase of luciferase activity was observed in C6-Fluc seeded with chitosan according to the increase in the number of cells. C6-Fluc/chitosan complex subcutaneously implanted into nude mice showed longitudinal bioluminescence image until 34 days. Luciferase image of abdominal-injected C6-Fluc/PLLA complex was saturated in only 14 days, showing great cell growth due to abundant nutrients. F3 cells showed well-incorporated pattern with fibrous chitosan scaffold using scanning electron microscopy. F3 infected with Ad-Fluc showed >100-fold higher luciferase activity than luciferase activity in F3. Cell-number-dependent increase of luciferase activity was shown in F3-Fluc seeded on chitosan. F3-Fluc incorporation into chitosan after abdominal injection was clearly visible on bioluminescence image up to 11 days. Radionuclide imaging showed higher uptake by MSC-NIS on PLLA scaffolds than by MSC-NIS not seeded on a scaffold. Quantitative data showed significantly better survival of MSC-NIS on PLLA scaffolds than without scaffold at 72 h post-implantation, which concurred with histologic findings. CONCLUSION: These results suggest that NSC-Fluc and MSC-NIS cells incorporated within polymer scaffolds can be monitored on a long-term basis by serial in vivo imaging. We believe that a biocompatible scaffold-based imaging system could be used to assess stem cell viabilities in a non-invasive way to aid the development of regenerative therapeutics.

Consideration of serum glucose levels during malignant mediastinal lymph node detection in non-small-cell lung cancer by FDG-PET.

BACKGROUND AND OBJECTIVE: Glucose and FDG compete for uptake by cancers. Here, we undertook to improve diagnostic accuracy of FDG-PET for determining mediastinal lymph node (LN) status in NSCLC by considering serum glucose level. METHODS: NSCLC patients (n = 70) who underwent curative lung resection and mediastinal LN dissection within 1 month of FDG-PET were enrolled. MaxSUV was calculated using lean body weight and used to determine a new parameter (maxSUV x serum glucose level; maxSUV-GL). Histopathologic LN results were compared with maxSUV and maxSUV-GL values. RESULTS: Of 71 LN stations whose FDG uptake could be measured, 21 were malignant and 50 benign. MaxSUV of LN had AUC of 0.729 (95% CI: 0.610-0.827) by ROC analysis with sensitivity of 47.6% (10/21), specificity of 94.0% (47/50), and a cutoff value of 3.3. Using maxSUV-GL the corresponding values were; AUC 0.825 (95% CI: 0.716-0.905) and sensitivity 76.2% (16/21), with a cutoff value of 290.4, which represented a significant improvement (P < 0.01) without compromising specificity 88.0% (44/50) (P > 0.05). The exclusion of neo-adjuvant chemotherapeutic and diabetic patients resulted in a similar improvement in diagnostic accuracy. CONCLUSION: By considering serum glucose level during FDG-PET using the new parameter maxSUV-GL, sensitivity for malignant mediastinal LN detection is improved.