Purpose To determine the diagnostic accuracy of a semiautomated 18F-FDG PET/CT measurement of total lesion glycolysis (TLG), maximum and peak standardized uptake value at lean body mass (SUL-Max and SUL-Peak), qualitative estimates of left/right nodal symmetry and FDG uptake for differentiating lymphoma from reactive adenopathy in HIV-infected patients. Methods We retrospectively analyzed 41 whole-body 18F-FDG PET/CT studies performed in HIV-infected patients for clinical reasons. The study received institutional review board approval. Of the 41 patients, 19 had biopsy-proven untreated lymphoma, and 22 with reactive adenopathy without malignancy on follow-up were used as controls. Nodal and extranodal visual qualitative metabolic scores, SUL-Max, SUL-Peak, CT nodal size, and PERCIST 1.0 threshold-based TLG and metabolic tumor volume (MTV) were determined. The qualitative intensity of nodal involvement and symmetry of uptake were compared using receiver operator curve (ROC) analysis. HIV plasma viral RNA measurements were also obtained. Results All of the quantitative PET metrics performed well in differentiating lymphoma from reactive adenopathy and performed better than qualitative visual intensity scores. The areas under the ROC curves (AUC) were significantly higher for TLG=0.96, single SUL-Peak=0.96, single SUL-Max=0.97, and MTV=0.96, compared to 0.67 for CT nodal size (p<0.001). These PET metrics performed best in separating the two populations in aviremic patients, with AUCs of 1 (AUC 0.91 for CT nodal size). TLG, MTV, SUL-Peak and SUL-Max were more reliable markers among viremic individuals, with AUCs between 0.84 and 0.93, compared to other metrics. PET metrics were significantly correlated with plasma viral load in HIV-reactive adenopathy controls. Asymmetrical FDG uptake had an accuracy of 90.4 % for differentiating lymphoma from reactive adenopathy in HIV-infected patients. Conclusion Quantitative PET metabolic metrics as well as the qualitative assessment of symmetry of nodal uptake appear to be valuable tools for differentiating lymphoma from reactive adenopathy in HIV-infected patients using FDG PET. These parameters appear more robust in aviremic patients.
Epigenetic modifiers, including the histone deacetylase inhibitor vorinostat, may sensitize tumors to chemotherapy and enhance outcomes. We conducted a multicenter randomized phase II neo-adjuvant trial of carboplatin and nanoparticle albumin-bound paclitaxel (CP) with vorinostat or placebo in women with stage II/III, human epidermal growth factor receptor 2 (HER2)–negative breast cancer, in which we also examined whether change in maximum standardized uptake values corrected for lean body mass (SULmax) on 18F-FDG PET predicted pathologic complete response (pCR) in breast and axillary lymph nodes. Methods Participants were randomly assigned to 12 wk of preoperative carboplatin (area under the curve of 2, weekly) and nab-paclitaxel (100 mg/m2 weekly) with vorinostat (400 mg orally daily, days 1–3 of every 7-d period) or placebo. All patients underwent 18F-FDG PET and research biopsy at baseline and on cycle 1 day 15. The primary endpoint was the pCR rate. Secondary objectives included correlation of change in tumor SULmax on 18F-FDG PET by cycle 1 day 15 with pCR and correlation of baseline and change in Ki-67 with pCR. Results In an intent-to-treat analysis (n = 62), overall pCR was 27.4% (vorinostat, 25.8%; placebo, 29.0%). In a pooled analysis (n = 59), we observed a significant difference in median change in SULmax 15 d after initiating preoperative therapy between those achieving pCR versus not (percentage reduction, 63.0% vs. 32.9%; P = 0.003). Patients with 50% or greater reduction in SULmax were more likely to achieve pCR, which remained statistically significant in multivariable analysis including estrogen receptor status (odds ratio, 5.1; 95% confidence interval, 1.3–22.7; P = 0.023). Differences in baseline and change in Ki-67 were not significantly different between those achieving pCR versus not. Conclusion Preoperative CP with vorinostat or placebo is associated with similar pCR rates. Early change in SULmax on 18F-FDG PET 15 d after the initiation of preoperative therapy has potential in predicting pCR in patients with HER2-negative breast cancer. Future studies will further test 18F-FDG PET as a potential treatment-selection biomarker.
OBJECTIVE. Cervical cancer is the second most common malignancy in women worldwide and the third most common cause of cancer mortality in the United States. The aim of this article is to describe cervical cancer and outline the value of (18)F-FDG PET/CT in the management of cervical malignancy. CONCLUSION. The value of PET/CT has been found in staging and treatment strategy for cervical cancer. FDG PET/CT facilitates decision-making and radiation treatment planning and provides important information about treatment response, disease recurrence, and long-term survival.
Multi-Bed FDG PETtCT as applied to oncologic imaging is currently widely and routinely used for assessment of localized and metastatic disease involvement. In the past, based on conventional (single-bed) dynamic PET imaging, standard tracer kinetic modeling techniques have been developed to estimate the FDG uptake rate Kj. However, routine clinical multi-bed FDG PET imaging commonly involves a single time frame per bed, i.e. static imaging, and the standardized uptake value (SDV), a surrogate of metabolic activity, is employed to estimate the uptake rate Kj• The accuracy depends on two conditions:(i) in the voxel or region of interest, contribution of non-phosphorylated FDG is negligible relative to phosphorylated FDG, and (ii) time integral of plasma FDG concentration is proportional to injected dose divided by lean body mass, which can fail in clinical FDG PET imaging and pose problems in differentiating malignant from benign tumors. The objective of the proposed work is to facilitate, for the fist time, a transition from static to dynamic multi-bed FDG PETtCT imaging in clinically feasible times where, given the challenge of sparse tem poral sampling at each bed, novel dynamic acquisition schemes should be employed to yield quantitative whole-body imaging of FDG uptake. Thus, a set of novel dynamic multi-bed PET image acquisition schemes have been modeled, using Monte Carlo simulations, to quantitatively evaluate the clinical feasibility of the method and optimize the number of passes per bed and the total study duration. It has been determined that a data acquisition scheme consisting of 6 whole-body passes and constant time frames of 45sec produces parametric images with the optimal noise vs. bias performance. Finally, clinical whole-body patient data have been acquired dynamically and results demonstrate the potential of the proposed method in enhancing treatment response monitoring capabilities of clinical PET studies.
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