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Positron emission tomography with fluorine-18-deoxyglucose (FDG-PET) detects active lymphoid tissues during HIV-1 infection in man. We used FDG-PET to study anatomical correlates of HIV-1 infection in man. Whole-body FDG-PET images from 15 patients with HIV-1 showed distinct lymphoid tissue activation in the head and neck during acute disease, a generalised pattern of peripheral lymph-node activation at mid-stages, and involvement of abdominal lymph nodes during late disease. Unexpectedly, HIV-1 progression was evident by distinct anatomical correlates, suggesting that lymphoid tissues are engaged in a predictable sequence. Understanding the anatomy of HIV-1 infection could encourage use of surgical or radiological interventions to supplement chemotherapy. [ABSTRACT FROM AUTHOR]

Purpose: The clinical utility of positron emission tomography/computed tomography (PET/CT) in comparison to standard workup in patients with known or suspected inflammatory bowel disease (IBD) is unknown.Procedures: Clinical data were collected on seven patients with known or suspected IBD undergoing PET/CT. Standard workup included history, physical exam, laboratory tests, colonoscopy and/or cross-sectional imaging. We divided the intestine into five regions [small bowel and four colon (ascending, transverse, descending and rectosigmoid)] and graded relative standard uptake values 0, 1, 2 or 3 by comparison to the liver, using a region-of-interest analysis (0 = no activity, 1 = liver, 2 and 3 = significant inflammation).Results: In patients 1 and 2, PET/CT demonstrated more activity than we thought clinically present. The other patients avoided unnecessary escalation or initiation of IBD therapy based on PET/CT results. Compared with standard workup, all seven patients had superior results when therapeutic decisions were based on PET/CT.Conclusions: We found PET/CT to be very useful in diagnosis and management in patients with known or suspected IBD. [ABSTRACT FROM AUTHOR]

Abstract: Assessment of treatment response in acute leukemia is routinely performed after therapy via bone marrow biopsy. We investigated the use of positron emission tomography (PET) for early assessment of treatment response in patients with acute myeloid leukemia (AML), using the proliferation marker 3′-deoxy-3′-[18F]fluoro-l-thymidine (FLT). Eight adult AML patients receiving induction chemotherapy underwent whole-body FLT PET/CT scans acquired at different time points during therapy. Patients who entered complete remission (CR) exhibited significantly lower FLT uptake in bone marrow than those patients with resistant disease (RD). In bone marrow, mean and maximum standardized uptake values were 0.8, 3.6 for CR and 1.6, 11.4 for RD, p <0.001. FLT PET results for CR and RD patients were independent of assessment time point, suggesting that FLT PET scans acquired as early as 2 days after chemotherapy initiation may be predictive of clinical response. This pilot study suggests that FLT PET imaging during induction chemotherapy may serve as an early biomarker of treatment response in AML. [Copyright &y& Elsevier]

Purpose: Accurate staging of esophageal cancer (ECA) is critical in determining appropriate therapy. Endoscopic ultrasound (EUS), computed tomography (CT) and positron emission tomography (PET) scanning can be used, but limited data exists regarding the use of combined PET/CT fusion imaging and EUS in ECA staging. The objective of this study is to evaluate the role of integrated PET/CT imaging and EUS in the staging of ECA.Procedures: Identification of patients diagnosed with ECA from 2004 to 2007 that underwent staging PET/CT and EUS. Data regarding tumor detection, lymph node identification, presence of metastatic disease, and affect on patient management were collected and compared between PET/CT and EUS.Results: Eighty-one patients (65 male, 16 female) were identified with mean age of 63.5 years who underwent EUS and PET/CT to stage known ECA. PET/CT identified the primary tumor in 74/81 (91.4%) of cases, compared to 81/81 (100%) with EUS. Locoregional adenopathy was seen by PET/CT in 29/81 (35.8%) of cases, compared to 49/81 (60.5%) by EUS (p = 0.0001). PET/CT identified celiac axis adenopathy in 8/81 (9.9%) of cases, compared to 11/81 (13.6%) with EUS (p = 0.5050). PET/CT identified 17/81 (21.0%) of patients with distant metastases who subsequently did not undergo attempt at curative surgical resection.Conclusions: In ECA, EUS is superior to PET/CT for T staging and in identifying locoregional nodes, while PET/CT provides M staging. EUS and integrated PET/CT appear to independently affect treatment decisions, indicating complimentary and necessary roles in the staging of ECA. [ABSTRACT FROM AUTHOR]

Abstract: Spatial organization of tumor phenotype is of great interest to radiotherapy target definition and outcome prediction. We characterized tumor phenotype in patients with cancers of the oropharynx through voxel-based correlation of PET images of metabolism, proliferation, and hypoxia. Methods: Patients with oropharyngeal cancer received 18F-fluorodeoxyglucose (FDG) PET/CT, 18F-fluorothymidine (FLT) PET/CT, and 61Cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) PET/CT. Images were co-registered and standardized uptake values (SUV) were calculated for all modalities. Voxel-based correlation was evaluated with Pearson’s correlation coefficient in tumor regions. Additionally, sensitivity studies were performed to quantify the effects of image segmentation, registration, noise, and segmentation on R. Results: On average, FDG PET and FLT PET images were most highly correlated (R FDG:FLT =0.76, range 0.53–0.85), while Cu-ATSM PET showed greater heterogeneity in correlation to other tracers (R FDG:Cu-ATSM =0.64, range 0.51–0.79; R FLT:Cu-ATSM =0.61, range 0.21–0.80). Of the tested parameters, correlation was most sensitive to image registration. Misregistration of one voxel lead to ΔR FDG =0.25, ΔR FLT =0.39, and ΔR Cu-ATSM =0.27. Image noise and reconstruction also had quantitative effects on correlation. No significant quantitative differences were found between GTV, expanded GTV, or CTV regions. Conclusions: Voxel-based correlation represents a first step into understanding spatial organization of tumor phenotype. These results have implications for radiotherapy target definition and provide a framework to test outcome prediction based on pretherapy distribution of phenotype. [Copyright &y& Elsevier]

Abstract: Objectives: The goals of this work were (1) to determine the effect of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET), MRI, and EEG on the decision to perform temporal lobe epilepsy (TLE) surgery, and (2) to determine if FDG-PET, MRI, or EEG predicts surgical outcome. Methods: All PET scans ordered (2000–2010) for epilepsy or seizures were tabulated. Medical records were investigated to determine eligibility and collect data. Statistical analysis included odds ratios, κ statistics, univariate analysis, and logistic regression. Results: Of the 186 patients who underwent FDG-PET, 124 had TLE, 50 were surgical candidates, and 34 had surgery with post-operative follow-up. Median length of follow-up was 24months. MRI, FDG-PET, and EEG were significant predictors of surgical candidacy (P <0.001) with odds ratios of 42.8, 20.4, and 6.3, respectively. FDG-PET was the only significant predictor of postoperative outcome (P <0.01). Conclusion: MRI showed a trend toward having the most influence on surgical candidacy, but only FDG-PET predicted surgical outcome. [Copyright &y& Elsevier]

Purpose: The purpose of this study was to evaluate the appropriate 2-deoxy-2-[(18)F]fluoro-D-glucose-positron emission tomography (FDG-PET) determination in patients with inflammatory bowel disease (IBD) before and after clinical improvement to see if this determination correlates with clinical activity.Procedures: We performed PET-computed tomography (PET/CT) on five patients before and after successful medical therapy in patients with moderately active IBD. Each patient had five bowel segments scored (0-3) for the appropriate FDG-PET determination.Results: There were five patients [Crohn's disease (CD) = 3, ulcerative colitis = 2] who were studied an average of 437 days (range, 77-807) after initial PET/CT scan. All patients showed significant improvement in physician global assessment scores (p = 0.004) and underwent repeat PET/CT. The total score of all segments was 32 pretreatment and 14 posttreatment (p < 0.01). Of 11 pretreatment active segments, nine (82%) segments either became inactive or displayed decreased activity, while two showed no change (p < 0.001).Conclusion: Appropriate FDG-PET determination decreases with successful treatment of inflammation in active IBD and correlates with symptom improvement. [ABSTRACT FROM AUTHOR]