Serial 18F-FDG Research Articles

Increases in Serial Pretreatment 18F-FDG PET-CT Metrics Predict Survival in Early Stage Non-Small Cell Lung Cancer Treated With Stereotactic Ablative Radiation Therapy

PurposeQuantitative changes in positron emission tomography with computed tomography imaging metrics over serial scans may be predictive biomarkers. We evaluated the relationship of pretreatment metabolic tumor growth rate (MTGR) and standardized uptake value velocity (SUVV) with disease recurrence or death in patients with early-stage non-small cell lung cancer treated with stereotactic ablative radiation therapy (SABR). Methods and MaterialsUnder institutional review board approval, we retrospectively identified patients who underwent positron emission tomography with computed tomography at diagnosis and staging and simulation for SABR. Two cohorts underwent SABR between November 2005 to October 2012 (discovery) and January 2012 to April 2016 (validation). MTGR and SUVV were calculated as the daily change in metabolic tumor volume and maximum standardized uptake value, respectively. Cox proportional hazard models identified predictors of local, regional, and distant recurrence and death for the combined cohort. MTGR and SUVV thresholds dichotomizing risk of death in the discovery cohort were applied to the validation cohort. ResultsA total of 152 lesions were identified in 143 patients (92 lesions in 83 discovery cohort patients). In multivariable models, increasing MTGR trended toward increased hazard of distant recurrence (hazard ratio, 6.98; 95% confidence interval, 0.67-72.61; P = .10). In univariable models, SUVV trended toward risk of death (hazard ratio, 11.8, 95% confidence interval, 0.85-165.1, P = .07). MTGR greater than 0.04 mL/d was prognostic of decreased survival in discovery (P = .048) and validation cohorts (P < .01). ConclusionsMTGR greater than 0.04 mL/d is prognostic of death in patients with non-small cell lung cancer treated with SABR. Increasing SUVV trends, nonsignificantly, toward increased risk of recurrence and death. MTGR and SUVV may be candidate imaging biomarkers to study in trials evaluating systemic therapy with SABR for patients at high risk of out-of-field recurrence.

Increased brain glucose metabolism in chronic severe traumatic brain injury as determined by longitudinal 18F-FDG PET/CT

Little is known about changes in glucose metabolism in patients with chronic severe traumatic brain injury (sTBI). It remains to be elucidated how neurological manifestations of sTBI are associated with brain glucose metabolism during longitudinal follow-up. We show here that neurological manifestations are associated with changes of brain glucose metabolism by using two serial 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) images. In this longitudinal observational study, two serial 18F-FDG PET/CT images from each of 45 patients were analyzed for whole-brain maximum standardized uptake values (SUVmax). For clinical assessment, we applied two different scales: the coma recovery scale-revised and the original Chiba score with additional information regarding nutrition, excretion, facial expression, and position change of the patient's relative immobility and bedridden state. As a result, the increased FDG uptake group was associated with a high level of wakefulness (first PET, p = 0.04; second PET, p = 0.01) and small ventricular size (first PET, p = 0.01; second PET, p = 0.01). In addition, anticonvulsant withdrawal (p = 0.001), improvement of total Chiba score (p = 0.01), language expression (p = 0.03), position change (p = 0.03), and communication (p = 0.03) were accelerated in the increased FDG uptake group. Spearman’s rank correlation coefficients of change in SUVmax and language expression between the first and second PET were 0.4 (p = 0.01). Our results indicate that chronic severe traumatic head injury patients have changed brain glucose metabolism.

Use of 18F-FDG PET/CT to predict short-term outcomes early in the course of chemoradiotherapy in stage III adenocarcinoma of the lung.

The purpose of the present prospective study was to evaluate the use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the assessment of therapy response and the prediction of short-term outcomes by maximum and mean standardized uptake values (SUVmax and SUVmean, respectively), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) following chemoradiotherapy (CRT) in patients with stage III adenocarcinoma of the lung. The study included a total of 15 patients, all of whom underwent two serial 18F-FDG PET/CT scans prior to and following 60-Gy radiotherapy with a concurrent cisplatin/pemetrexed combined chemotherapy regimen. SUVmax, SUVmean, MTV and TLG were determined. Short-term outcomes were assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST) and the PET Response Criteria in Solid Tumors (PERCIST). Post-CRT SUVmax, ΔSUVmax, ΔMTV and ΔTLG varied significantly between responders and non-responders (P=0.009, P=0.015, P=0.006 and P=0.004, respectively). The differences in SUVmax, SUVmean, carcinoembryonic antigen, MTV and TLG between the responders and the non-responders at the initial 18F-FDG PET/CT scans were not statistically significant (P>0.05). The overall response rate was significantly higher (P=0.01) when evaluated using PERCIST compared with evaluation using RECIST. It was concluded that post-CRT SUVmax, ΔSUVmax, ΔMTV and ΔTLG may be used to differentiate the responders from the non-responders following CRT for stage III adenocarcinoma of the lung. This would aid in deciding whether or not to increase dosages or to incorporate a boost treatment without the requirement to suspend therapy.

Prospective Study of Serial 18F-FDG PET and 18F-Fluoride PET to Predict Time to Skeletal-Related Events, Time to Progression, and Survival in Patients with Bone-Dominant Metastatic Breast Cancer.

Assessing therapy response of breast cancer bone metastases is challenging. In retrospective studies, serial 18F-FDG PET was predictive of time to skeletal-related events (tSRE) and time to progression (TTP). 18F-NaF PET improves bone metastasis detection compared with bone scanning. We prospectively tested 18F-FDG PET and 18F-NaF PET to predict tSRE, TTP, and overall survival (OS) in patients with bone-dominant metastatic breast cancer (MBC). Methods: Patients with bone-dominant MBC were imaged with 18F-FDG PET and 18F-NaF PET before starting new therapy (scan1) and again at a range of times centered around approximately 4 mo later (scan2). Maximum standardized uptake value (SUVmax) and lean body mass adjusted standardized uptake (SULpeak) were recorded for a single index lesion and up to 5 most dominant lesions for each scan. tSRE, TTP, and OS were assessed exclusive of the PET images. Univariate Cox regression was performed to test the association between clinical endpoints and 18F-FDG PET and 18F-NaF PET measures. mPERCIST (Modified PET Response Criteria in Solid Tumors) were also applied. Survival curves for mPERCIST compared response categories of complete response+partial response+stable disease versus progressive disease for tSRE, TTP, and OS. Results: Twenty-eight patients were evaluated. Higher 18F-FDG SULpeak at scan2 predicted shorter time to tSRE (P = <0.001) and TTP (P = 0.044). Higher 18F-FDG SUVmax at scan2 predicted a shorter time to tSRE (P = <0.001). A multivariable model using 18F-FDG SUVmax of the index lesion at scan1 plus the difference in SUVmax of up to 5 lesions between scans was predictive for tSRE and TTP. Among 24 patients evaluable by 18F-FDG PET mPERCIST, tSRE and TTP were longer in responders (complete response, partial response, or stable disease) than in nonresponders (progressive disease) (P = 0.007, 0.028, respectively), with a trend toward improved survival (P = 0.1). An increase in the uptake between scans of up to 5 lesions by 18F-NaF PET was associated with longer OS (P = 0.027). Conclusion: Changes in 18F-FDG PET parameters during therapy are predictive of tSRE and TTP, but not OS. mPERCIST evaluation in bone lesions may be useful in assessing response to therapy and is worthy of evaluation in multicenter, prospective trials. Serial 18F-NaF PET was associated with OS but was not useful for predicting TTP or tSRE in bone-dominant MBC.

Primary Thyroid Lymphoma: External Beam Radiation Therapy Induced Thyroiditis Mimics Residual Disease on Serial 18F-FDG PET/CT Imaging.

A 67-year-old female patient with no prior history of benign thyroid disease was diagnosed with primary thyroid lymphoma and was staged with18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT). She was treated with chemotherapy and external beam radiation therapy, and a follow-up PET/CT showed significant reduction in the size of the thyroid lymphoma with persistent intense 18F-FDG uptake, which was interpreted as partial response to therapy. However, two subsequent PET/CT studies showed no change in the persistent intense 18F-FDG uptake in the thyroid and a biopsy confirmed the presence of thyroiditis with no evidence of residual lymphoma. Follow-up PET/CTs performed over the subsequent three years showed stable intensely 18F-FDG avid thyroiditis with no evidence of lymphoma recurrence. We present the imaging characteristics of a long term radiation treatment induced thyroiditis mimicking 18F-FDG avid residual disease on PET/CT.

18F-fluorodeoxyglucose positron emission computed tomography for monitoring tumor response in esophageal carcinoma treated with concurrent chemoradiotherapy.

The aim of the present study was to explore the value of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in monitoring the early tumor response of esophageal squamous cell carcinoma (ESCC) treated with concurrent chemoradiotherapy (CRT). A total of 48 patients with pathologically proven ESCC were retrospectively analyzed. All patients underwent two serial 18F-FDG PET scans at baseline (pre-CRT) and 40 Gy/4 weeks of starting radiation therapy (inter-CRT). All patients received intensity-modulated radiotherapy (with a total radiation dose of 59.6 Gy) concurrently with cisplatin-based chemotherapy. The maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) were measured using 18F-FDG PET. The percentage changes (Δ) in SUVmax and MTV between two serial scans were calculated and were revealed to be associated with the objective tumor response (oTR), according to the Response Evaluation Criteria in Solid Tumors 1.1. Among the 48 patients, 20.8% achieved a complete response, 68.8% exhibited a partial response and the oTR rate was 89.6%. On the pre-CRT PET scans, the mean SUVmax and MTV were 14.1±5.8 and 58.2±25.4 cm3, respectively. Following 40 Gy irradiation over 4 weeks, the mean SUVmax and MTV significantly decreased to 4.3±3.5 and 19.0±12.1 cm3, respectively (P<0.001). A significantly higher ΔSUVmax and ΔMTV was observed in the responders compared with that in the non-responders [0.71±0.16 vs. 0.51±0.26 (P=0.015); and 0.64±0.13 vs. 0.42±0.09 (P=0.001), respectively]. Univariate analysis revealed that ΔSUVmax and ΔMTV were significantly associated with oTR (P=0.010 and P=0.001, respectively). ΔMTV was used as a predictor and a cut-off value of 54% discriminated responders from non-responders with a sensitivity of 69.8% and a specificity of 100% (P=0.001). The area under the receiver operating characteristic curve was 0.837 (95% confidence interval, 0.702-0.928). The results of the present study indicated that interim 18F-FDG PET scans may provide early prognostic value for determining oTR in patients with ESCC undergoing treatment with CRT.

Doxorubicin Effect on Myocardial Metabolism as a Prerequisite for Subsequent Development of Cardiac Toxicity: A Translational 18F-FDG PET/CT Observation.

The present translational study aimed to verify whether serial 18F-FDG PET/CT predicts doxorubicin cardiotoxicity. Methods: Fifteen athymic mice were treated intravenously with saline (n = 5) or with 5 or 7.5 mg of doxorubicin per kilogram (n = 5 each) and underwent dynamic small-animal PET beforehand and afterward to estimate left ventricular (LV) metabolic rate of glucose (MRGlu). Thereafter, we retrospectively identified 69 patients who had been successfully treated with a regimen of doxorubicin, bleomycin, vinblastine, and dacarbazine for Hodgkin disease (HD) and had undergone 4 consecutive 18F-FDG PET/CT scans. Volumes of interest were drawn on LV myocardium to quantify mean SUV. All patients were subsequently interviewed by telephone (median follow-up, 30 mo); 36 of them agreed to undergo electrocardiography and transthoracic echocardiography. Results: In mice, LV MRGlu was 17.9 ± 4.4 nmol × min-1 × g-1 at baseline. Doxorubicin selectively and dose-dependently increased this value in the standard-dose (27.9 ± 9 nmol × min-1 × g-1, P < 0.05 vs. controls) and high-dose subgroups (37.2 ± 7.8 nmol × min-1 × g-1, P < 0.01 vs. controls, P < 0.05 vs. standard-dose). In HD patients, LV SUV showed a progressive increase during doxorubicin treatment that persisted at follow-up. New-onset cardiac abnormalities appeared in 11 of 36 patients (31%). In these subjects, pretherapy LV SUV was markedly lower with respect to the remaining patients (1.53 ± 0.9 vs. 3.34 ± 2.54, respectively, P < 0.01). Multivariate analysis confirmed the predictive value of baseline LV SUV for subsequent cardiac abnormalities. Conclusion: Doxorubicin dose-dependently increases LV MRGlu, particularly in the presence of low baseline 18F-FDG uptake. These results imply that low myocardial 18F-FDG uptake before the initiation of doxorubicin chemotherapy in HD patients may predict the development of chemotherapy-induced cardiotoxicity, suggesting that prospective clinical trials are warranted to test this hypothesis.

Establishing 177Lu-PSMA-617 Radioligand Therapy in a Syngeneic Model of Murine Prostate Cancer.

Clinical 177Lu-PSMA-617 radioligand therapy (RLT) is applied in advanced-stage prostate cancer. However, to the best of our knowledge murine models to study the biologic effects of various activity levels have not been established. The aim of this study was to optimize specific and total activity for 177Lu-PSMA-617 RLT in a syngeneic model of murine prostate cancer. Methods: Murine-reconstituted, oncogene-driven prostate cancer cells (0.1 × 106) (RM1), transduced to express human prostate-specific membrane antigen (PSMA), were injected into the left flank of C57Bl6 immunocompetent mice. RLT was performed by administering a single tail vein injection of 177Lu-PSMA-617 at different formulations for specific (60 MBq at high, 62 MBq/nmol; intermediate, 31 MBq/nmol; or low 15 MBq/nmol specific activity) or total activity (30, 60, or 120 MBq). Organ distribution was determined by ex vivo γ-counter measurement. DNA double-strand breaks were measured using anti-gamma-H2A.X (phospho S139) immunohistochemistry. Efficacy was assessed by serial CT tumor volumetry and 18F-FDG PET metabolic volume. Toxicity was evaluated 4 wk after the start of RLT. Results: Mean tumor-to-kidney ratios ± SEM were 19 ± 5, 10 ± 5, and 2 ± 0 for high, intermediate, and low (each n = 3) specific activity, respectively. Four of 6 (67%) mice treated with intermediate or high specific activity and none of 6 (0%) mice treated with low specific activity or formulation demonstrated significant DNA double-strand breaks (≥5% γ-H2A.X-positive cells). High when compared with intermediate or low specific activity resulted in a lower mean ± SEM tumor load by histopathology (vital tissue, 4 ± 2 vs. 8 ± 3 mm2; n = 3 vs. 6), day-4 18F-FDG PET (metabolic volume, 87 ± 23 vs. 118 ± 14 mm3; n = 6 vs. 12), and day-7 CT (volume, 323 ± 122 vs. 590 ± 46 mm3; n = 3 vs. 6; P = 0.039). 177Lu-PSMA-617 (120 MBq) with high specific activity induced superior tumor growth inhibition (P = 0.021, n = 5/group) without subacute hematologic toxicity (n = 3/group). Conclusion:177Lu-PSMA-617 (120 MBq) and high specific activity resulted in the highest efficacy in a syngeneic model of murine prostate cancer. The model will be useful for studying the effects of PSMA-directed RLT combined with potentially synergistic pharmacologic approaches.

Oncocytoma as a growing FDG-avid adrenal mass on serial 18F-FDG PET/CT imaging: A potential pitfall in oncological evaluation

Oncocytoma as a growing FDG-avid adrenal mass on serial 18F-FDG PET/CT imaging: A potential pitfall in oncological evaluation

In Vivo Dynamic Metabolic Changes After Transplantation of Induced Pluripotent Stem Cells for Ischemic Injury.

Serial 18F-FDG PET, echocardiographic, immunohistochemical, and immunofluorescence studies were performed after transplantation of iPSCs and iPSC-CMs and compared with embryonic stem cells (ESCs), ESC-CMs, and a phosphate-buffered saline control group of rats with myocardial infarction. Increased glucose metabolism in periinfarct areas and improved myocardial function were observed in the stem cell transplantation groups compared with the control group, and serial immunofluorescence and immunohistochemical results exhibited the survival and migration of stem cells during the study period. Serial 18F-FDG PET and echocardiographic imaging studies demonstrated the dynamic metabolic changes and recovery of myocardial function after stem cell transplantation. 18F-FDG PET could be a potential approach to evaluating spatiotemporal dynamic metabolic changes in vivo after transplantation of iPSCs or iPSC-CMs for ischemic injury.

Co-localisation analysis of brown adipose deposits on serial 18F-FDG PET/CT scans implies fixed deposits

Purpose: Brown adipose tissue (BAT) is the primary effector organ for non-shivering thermogenesis (NST), which positron emission tomography/computed tomography (PET/CT) studies have shown to be far more prevalent in adult humans than was hitherto believed. Research into weight loss by NST modulation through BAT manipulation requires a reliable imaging biomarker. This study evaluates patterns of BAT uptake on serial PET/CT scans to determine the degree of coincidence over time and the accuracy of PET/CT as a reference standard.

Cardiac PET Provides Clinically Useful Assessment for Measuring Treatment Response to Adjuvant High Dose Methotrexate in a Complex Case of Cardiac Sarcoidosis

Sarcoidosis is a multisystem granulomatous disease in which cardiac involvement is a serious condition with diagnostic challenges. The mainstay of therapy involves corticosteroids, however treatment algorithms beyond this remain undefined. We report a case of sarcoidosis in a morbidly obese patient with claustrophobia who had primarily cardiac and lymph node involvement. Diagnosis involved the use of multi imaging modalities including computed tomography, echocardiography, cardiac magnetic imaging (CMR) and 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET). Progression of the disease lead to the the insertion of an implantable cardiac device, which precluded follow up with CMR to monitor disease activity. Echocardiography revealed progressive left ventricular decline, the aetiology of which was thought to be either high burden of right ventricular pacing or increased disease activity. Follow-up 18F-FDG PET scanning demonstrated a substantial initial response to high dose corticosteroids, however this was limited by severe steroid related side effects. Additionally, 18F-FDG PET scanning was used to demonstrate disease reactivation with steroid weaning and an initial lack of response to adjunctive oral methotrexate and cyclosporin. Finally, it was used to demonstrate an impressive response to adjunctive high dose subcutaneous methotrexate. Furthermore, the initial 18F-FDG PET scan guided localisation of active superficial lymph nodes to facilitate a positive tissue biopsy. Although radiation exposure is a concern, the use of serial 18F-FDG PET scanning in this complex case proved invaulable in the diagnosis, assessment of disease activity and response to treatment in a perplexing evidence lacking area.

Abstract 618: Dual PI3K/mTOR inhibition as a treatment strategy for PIK3CA and APC mutant colorectal cancers

Abstract BACKGROUND: Colorectal cancer (CRC) is understood as a diverse group of cancers calling for the personalization of therapeutics to individual subtypes of CRC. Mutations in PIK3CA, which result in a constitutively active phosphoinositide-3-kinase protein (PI3K), are present in 20-30% of CRCs. Aberrations in the Adenomatous Polyposis Coli (APC) gene are found in 86% of PIK3CA mutant CRCs. The potential for treatment of tumors with this specific profile is of great interest. METHODS: Mice expressing a constitutively active PI3K and loss of APC were generated and spheroid cultures were derived from the resulting cancers. PIK3CA and APC mutant spheroids were treated with GDC0941 (GDC), a pan PI3K inhibitor, NVP-BYL719 (BYL), a PI3K alpha isomer specific inhibitor, or NVP-BEZ235 (BEZ), a dual mTOR/PI3K inhibitor. Proliferation was measured by changes in spheroid diameter over time. BEZ treatment of mice with PIK3CA and APC mutant CRCs was performed over 14 days. Tumor response was measured with serial murine colonoscopy and dual hybrid 18F-FDG PET/CT imaging. RESULTS: Persistent PIK3CA and APC mutant CRC spheroid growth was observed with BYL and GDC treatment, while BEZ treatment resulted in a significant reduction in spheroid size. Immunoblotting determined that this correlated with significant suppression of phosphorylated AKT, RPS6 and 4EBP1 in BEZ-treated spheroids and incomplete PI3K pathway inhibition following BYL and GDC treatment. BEZ treatment was then investigated in mice with PIK3CA and APC mutant CRCs. BEZ elicited a dramatic treatment response in these cancers on endoscopy, with a 53% decrease in median lumen occlusion compared to a 60% increase in controls over the 14 day treatment period. PET/CT imaging results confirmed these findings demonstrating a decrease in tumor size and avidity post BEZ treatment. BEZ resulted in inhibition of the PI3K pathway in these tumors. Reactivation of PI3K signaling was observed within 24 hours of the withdrawal of BEZ. BEZ was well-tolerated in these mice and associated with a decrease in the endoscopic anemia score. CONCLUSIONS: PIK3CA and APC mutant CRCs are a potentially targetable subtype of cancer. These cancers are resistant to proximal inhibition of the PI3K pathway, but are responsive to dual PI3K/mTOR inhibition. These results warrant further investigation in clinical studies. Citation Format: Susan Payne, Tyler Foley, Cheri Pasch, Alexander Yueh, Demetra Korkos, Dana Van De Hey, Linda Clipson, Dustin Deming. Dual PI3K/mTOR inhibition as a treatment strategy for PIK3CA and APC mutant colorectal cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 618.

The Predictive Value of Serial 18F-FDG PET/CT for Recurrence and Survival of Locally Advanced Non-Small Cell Lung Cancer After Concurrent Chemoradiation Therapy

The Predictive Value of Serial 18F-FDG PET/CT for Recurrence and Survival of Locally Advanced Non-Small Cell Lung Cancer After Concurrent Chemoradiation Therapy

Transplantation of induced pluripotent stem cells improves functional recovery in Huntington's disease rat model.

The purpose of this study was to determine the functional recovery of the transplanted induced pluripotent stem cells in a rat model of Huntington's disease with use of 18F-FDG microPET/CT imaging.MethodsIn a quinolinic acid-induced rat model of striatal degeneration, induced pluripotent stem cells were transplanted into the ipsilateral lateral ventricle ten days after the quinolinic acid injection. The response to the treatment was evaluated by serial 18F-FDG PET/CT scans and Morris water maze test. Histological analyses and Western blotting were performed six weeks after stem cell transplantation.ResultsAfter induced pluripotent stem cells transplantation, higher 18F-FDG accumulation in the injured striatum was observed during the 4 to 6-weeks period compared with the quinolinic acid-injected group, suggesting the metabolic recovery of injured striatum. The induced pluripotent stem cells transplantation improved learning and memory function (and striatal atrophy) of the rat in six week in the comparison with the quinolinic acid-treated controls. In addition, immunohistochemical analysis demonstrated that transplanted stem cells survived and migrated into the lesioned area in striatum, and most of the stem cells expressed protein markers of neurons and glial cells.ConclusionOur findings show that induced pluripotent stem cells can survive, differentiate to functional neurons and improve partial striatal function and metabolism after implantation in a rat Huntington's disease model.

Ultra Staging to Unmask the Prescribing of Adjuvant Therapy in Cancer Patients: The Future Opportunity to Image Micrometastases Using Total-Body 18F-FDG PET Scanning

Ultra Staging to Unmask the Prescribing of Adjuvant Therapy in Cancer Patients: The Future Opportunity to Image Micrometastases Using Total-Body ¹⁸F-FDG PET Scanning

Bone marrow mesenchymal stem cell transplantation in acute brain trauma

SummaryAim: This study was performed to evaluate the effects of intravenously transplanted rat bone-marrow derived mesenchymal stem cells (rBMSCs) in an acute brain trauma model using serial 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in rat models. Animals, methods: Trauma models were made using a controlled cortical impact injury device. The stem cell treatment group was treated with intravenous injections of BMSCs, and models without stem cell therapy comprised the control group. Serial 18F-FDG PET images were obtained 1, 7, 14, 21, and 28 days after trauma. The difference in 18F-FDG uptake between day 1 and each time point after trauma was analyzed with SPM2 (uncorrected p &lt; 0.005). Results: The stem cell treatment group demonstrated significantly higher 18F-FDG uptake in the right parietal region at 14 days after trauma than at 1 day after trauma. An increase in glucose metabolism in the right parietal cortex appeared on days 21 and 28 after trauma in the group without stem cell treatment. The 18F-FDG uptake in the brain was improved over a broader area, including the right parietal and right primary somatosensory cortex, on days 21 and 28 after trauma in the stem cell treatment group compared with the group without stem cell treatment. Conclusion: BMSC therapy in trauma models led to improved glucose metabolism. This result might support the therapeutic effect of stem cells in brain trauma.

18F-FDG PET in the Evaluation of Acuity of Deep Vein Thrombosis

F-FDG PET has been used for vascular disease, but its role in deep vein thrombosis (DVT) remains prospectively unexplored. Whole-body F-FDG PET/CT scans were performed in patients 1 to 10 weeks after onset of symptomatic DVT (n = 12) and in control subjects without DVT (n = 24). The metabolic activity (SUVmax) of thrombosed and contralateral nonthrombosed vein segments was determined. The sensitivity and specificity of F-FDG PET/CT for the diagnosis of DVT were determined by receiver operating characteristic curve analyses. In 2 patients with DVT, changes in the metabolic activity of thrombosed vein segments in serial F-FDG PET scans. The metabolic activity in thrombosed veins [SUVmax, 2.41 (0.75)] was visually appreciable and significantly higher than in nonthrombosed veins in either the contralateral extremity of patients with DVT [SUVmax, 1.09 (0.25), P = 0.007] or control subjects [1.21 (0.22), P < 0.001]. The area under the receiver operating characteristic curve for SUVmax was 0.9773 (P < 0.001), indicating excellent accuracy. An SUVmax threshold of greater than 1.645 was 87.5% sensitive and 100% specific for DVT. Metabolic activity in thrombosed veins correlated significantly with time from DVT symptom onset (decrease in SUVmax of 0.02/d, P < 0.05). Best-fit-line analyses suggested that approximately 84 to 91 days after acute DVT, the maximum metabolic activity of thrombosed veins would return to normal levels. F-FDG PET/CT is accurate for detecting acute symptomatic, proximal DVT. Metabolic activity in thrombosed veins decreases with time, suggesting that F-FDG PET may be helpful in assessing the age of the clot.

Distribution of 18F-FDG in a patient with evolving abdominal aortic aneurysm

We report the case of a patient with abdominal aortic aneurysm who underwent serial 18F-FDG PET/CT examinations to evaluate the risk of rupture and to guide appropriate surgical or medical management.

Inferior glucose metabolism and chemosensitivity of post-radiotherapy local recurrence in comparison with distant metastases as assessed by serial 18F-FDG PET/CT imaging.

e21004 Background: Patients locally recurring after radiotherapy have increased risk of metastatic progression. This study is to compare the glucose metabolism and chemosensitivity of recurrences and metastases in the same patient by serial FDG PET/CT imaging. Methods: The 18F-FDG PET/CT images of patients with both local recurrences and distant metastases after initial treatments (definitive radiotherapy/chemo-radiotherapy as radiation group, or radical surgery as surgery control group) were reviewed. The tumor maximal diameter on CT and PET images (DCT and DPET), maximal SUV (SUVmax), mean SUV (SUVmean) were measured. PET/CT scans were performed again within 1-4 weeks after further chemotherapy. The relative changes of DCT, DPET, SUVmax and SUVmean for each focus were calculated and compared between the recurrences and metastases for both groups. Results: In surgery group (10 patients), no significant difference was found in tumor size, FDG uptake and chemosensitivity between recurrences (20 foci) and metastases (32 foci). However, in radiation group (23 patients), both SUVmax (mean ± SE: 7.03 ± 0.46) and SUVmean (4.33 ± 0.22) of recurrences (57 foci) were lower than those (8.45 ± 0.53 and 5.36 ± 0.30, respectively, P < 0.05) of metastases (68 foci). Moreover, the response extents of recurrences (45 foci) were lower than that of metastases (46 foci), with ΔSUVmax% (-21.83 ± 6.41% vs. -44.37 ± 3.96%), ΔSUVmean% (-29.31 ± 5.68% vs. -49.93 ± 4.16%), ΔDCT% (-23.12 ± 6.43% vs. -50.45 ± 4.95%), and ΔDPET% (-21.8 ± 7.19% vs.-49.5 ± 5.49%, P < 0.05). Conclusions: The local recurrences within pre-irradiated field and distant metastases in the same patient do not share the same biological characteristics and treatment response, with the inferior glucose metabolism and chemosensitivity in local recurrent tumors.