PET for the Evaluation of Solitary Pulmonary Nodules

Shon

Internal Medicine Journal

2010

Positron emission tomography (PET) using fluorine-18-2-fluoro-2-deoxy-Dglucose (FDG) has made a major impact in clinical oncology in diagnosing, staging and restaging malignancy as well as in monitoring therapy response. Over the past decade, there has been an enormous growth in the scientific and clinical evidence supporting PET including recent important contribution from the Australian PET Data Collection Project. Since 2001, hybrid PET-computed tomography has also largely replaced PET alone systems with significant improvement in diagnostic accuracy. This review is a brief update on the current status of FDG-PET focusing on its oncologic applications.

Section: Positron Emission Tomographysupporting

confidence: 89%

Positron emission tomography: current status and future challenges

Shon

Internal Medicine Journal

2010

“…Most of the subjects in the study were male, which may limit generalizability of the results. Finally, we use the common maximum SUV threshold value of 2.5, which has been challenged in the literature as being too high and not specific enough to rule in underlying malignancy [20, 21]. While there remains significant debate around this threshold, at our institution, all lesions that are not excised/biopsied are followed for at least 2 years to document stability.…”

Section: Discussionmentioning

confidence: 99%

FDG PET/CT evaluation of pathologically proven pulmonary lesions in an area of high endemic granulomatous disease

2013

PurposeThe goal of this study is to assess how reliable the threshold maximum standardized uptake value (maxSUV) of 2.5 on positron emission tomography–computed tomography (PET/CT) is for evaluation of solitary pulmonary lesions in an area of endemic granulomatous disease and to consider other imaging findings that may increase the accuracy of PET/CT.Materials and methodsThe staging PET/CT of 72 subjects with solitary pulmonary lesions (nodules (less than 3 cm) or masses (greater than 3 cm)) were retrospectively reviewed. Pathology proven diagnosis from tissue samples was used as the gold standard. Logistic regression was used to assess whether the subject’s age, maxSUV, size of lesion, presence of emphysema, or evidence of granulomatous disease was predictive of malignancy.ResultsMalignant lesions were identified in 84.7 % (61/72) of the 72 subjects. A threshold maxSUV of 2.5 had a sensitivity of 95.1 % (58/61), specificity of 45.5 % (5/11), positive predictive value of 90.6 % (58/64), negative predictive value of 62.5 % (5/8) and an accuracy of 87.5 % (63/72). The false negative rate was 4.9 %, and the false positive rate was 54.5 %. All 3 false negatives were less than or equal to 1.0 cm; however, false positives ranged from 1.1 to 5.6 cm. The false negatives had a mean (SD) maxSUV of 2.0 (0.4), whereas the false positives had a mean (SD) maxSUV of 5.6 (3.0). Emphysema was associated with 1.1 higher odds of malignancy, and evidence of granulomatous disease was associated with 0.34 lower odds of benign disease, however, neither was statistically significant (p = 0.92 and p = 0.31, respectively). Higher maxSUV was significantly associated with increased risk of malignancy (p = 8.3 × 10−3). Older age and larger size of lesion were borderline associated with increased risk of malignancy (p = 0.05 and p = 0.07, respectively).ConclusionIn an area of high endemic granulomatous disease, the PET/CT threshold maxSUV of 2.5 retains a high sensitivity (95.1 %) and positive predictive value (90.6 %) for differentiating benign from malignant pulmonary lesions; however, the specificity (45.5) and negative predictive value (62.5) decrease due to increased false positives. The presence of emphysema and absence of evidence of granulomatous disease increases the probability that a pulmonary lesion is malignant; however, these were not statistically significant.

Nuclear Medicine and Biology

“…To the best of our knowledge, Kimura et al reported the synthesis of [ 18 F]Ex(9-39) via [ 18 F]SFB [19]. [ 18 F]SFB is an excellent reagent to label peptides with F-18; however, it is not site-specific since the active succinimidyl ester can react with any primary amine group within the peptide molecule.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and evaluation of [18F]exendin (9–39) as a potential biomarker to measure pancreatic β-cell mass

Wang

Lim

Normandin

et al. 2012

Introduction Glucagon-like peptide 1 (GLP-1) is released in response to food intake and plays an important role in maintaining blood glucose homeostasis. Exendin (9-39), a potent GLP-1R antagonist, has been labeled with In-111 for SPECT imaging. We report here the first radiosynthesis of [18F]exendin (9-39) ([18F]Ex(9-39)) and an evaluation of its potential as a biomarker for in vivo PET imaging of pancreatic β-cell mass (BCM) in rats. Methods F-18 label was introduced by conjugation of [18F]4-fluorobenzaldehyde with an Ex(9-39) derivative containing a 6-hydrazinonicotinyl group on the -amine of Lys27. PET imaging was carried out in Sprague-Dawley rats (5 control, 5 streptozotocin-induced diabetic) and BioBreeding-Diabetes Prone rats (3 at 7 wks, 3 at 12 wks) using HRRT following 0.187±0.084 mCi [18F]Ex(9-39) administration. Time activity curves were obtained from pancreas, liver and kidney. Pancreases were assayed for insulin content after the imaging study. Results Site-specifically labeled [18F]Ex(9-39) was purified on a G15 open column with radiochemical and chemical purities >98%. PET imaging showed pancreatic SUV peaked at 10 min, and plateaued by 50 min to the end of scan (240 min). No correlations of pancreatic SUV with post-mortem measures of insulin content were seen. Conclusions [18F]Ex(9-39) was successfully prepared and used for PET imaging for the first time to measure pancreatic BCM. The results suggest that derivatization of the Lys27 residue might reduce binding affinity, as evidenced by the absence of specific binding. Exendin analogs radiolabeled at other sites may elucidate the active site required for binding.