Flourodeoxyglucose Positron Emission Tomography Research Articles

Predictors of outcome in a contemporary cardiac sarcoidosis population: Role of brain natriuretic peptide, left ventricular function and myocardial inflammation.

Cardiac sarcoidosis (CS) is a potentially fatal condition that varies in its clinical presentation. Here, we describe baseline characteristics at presentation along with prognosis and predictors of outcome in a sizable and deeply phenotyped contemporary cohort of CS patients. Consecutive CS patients seen at one institution were retrospectively enrolled after undergoing laboratory testing, electrocardiogram, echocardiography, cardiac magnetic resonance (CMR) imaging and 18 F-flourodeoxyglucose positron emission tomography (FDG-PET) at baseline. The composite endpoint consisted of all-cause mortality, aborted sudden cardiac death, major ventricular arrhythmic events, heart failure hospitalization and heart transplantation. A total of 319 CS patients were studied (67% male, 55.4 ± 12 years). During a median follow-up of 2.2 years (range: 1 month-11 years), 8% of patients died, while 33% reached the composite endpoint. The annualized mortality rate was 2.7% and the 5- and 10-year mortality rates were 6.2% and 7.5%, respectively. Multivariate analysis showed serum brain natriuretic peptide (BNP) levels (hazard ratio [HR] 2.41, 95% confidence interval [CI] 1.34-4.31, p = 0.003), CMR left ventricular ejection fraction (LVEF) (HR 0.96, 95% CI 0.94-0.98, p < 0.0001) and maximum standardized uptake value of FDG-PET (HR 1.11, 95% CI 1.04-1.19, p = 0.001) to be independent predictors of outcome. These findings remained robust for different patient subgroups. Cardiac sarcoidosis is associated with significant morbidity and mortality, particularly in those with cardiac involvement as the first manifestation. Higher BNP levels, lower LVEF and more active myocardial inflammation were independent predictors of outcomes.

Focal nodular marrow hyperplasia: Imaging features of 53 cases.

To describe the characteristic imaging features of focal nodular marrow hyperplasia (FNMH). Retrospective review of all patients with a diagnosis of FNMH between January 2007 and September 2019. The study included 53 patients, 7 males and 46 females with a mean age of 58 years (range 12-95 years). All had MRI with conventional spin echo sequences showing a poorly defined round/oval lesion with mild T1W iso/hyperintensity compared to skeletal muscle, low T2W turbo spin echo (TSE) signal intensity (SI) compared to marrow fat and variable SI on STIR, but never associated with reactive marrow oedema. All 53 patients had follow-up MRI, with all lesions remaining stable or partially resolving. In-phase (IP) and out-of-phase (OP) chemical shift imaging (CSI) was obtained in 31 of these, with 28 (90.3%) showing >20% SI drop on the OP sequence, while 3 (9.7%) demonstrated <20% SI drop. CT was available in 26 cases, 17 (65.4%) showing mild medullary sclerosis. Single-photon emission computed tomography CT (SPECT-CT) was available in four cases and Flourodeoxyglucose positron emission tomography CT (FDG PET-CT) in 2, all showing increased uptake. Focal uptake was also seen in three of eight patients who had undergone whole body bone scintigraphy. Only one lesion was biopsied, confirming FNMH. The imaging appearances of FNMH have been described on various modalities, particularly MRI with emphasis on the role of IP and OP CSI typically demonstrating >20% SI reduction. FNMH should be recognised and treated as a 'do not touch' lesion which does not require biopsy or prolonged follow-up. We describe and clarify the imaging characteristics of FNMH on MRI, including CSI, CT and various nuclear medicine modalities. An imaging algorithm is suggested for allowing a non-invasive diagnosis.

18FDG-PET is sensitive tool for detection of extracranial tuberculous foci in central nervous system tuberculosis – Preliminary observations from a tertiary care center in northern India

PurposeTo study the role of 18FDG- PET (Flourodeoxyglucose positron emission tomography) in a) determining the extent of cranial and extra-cranial disease and b) diagnosis as well as prognosis of CNS TB (central nervous system tuberculosis) including TBM (tuberculous meningitis). Patients and methodsThis prospective observational study (n = 70) was carried out at a tertiary care institute in Northern India from 1.1.2017 to 30.6.2018. Diagnosis of TBM was made according to modified Ahuja's criteria. All patients were evaluated in detail and treated as per standard guidelines. All patients underwent 18FDG-PET scanning of brain and whole body at baseline. ResultsMean age was 35.2 ± 14.8 years. There were 37 men. Majority of patients (n = 47; 67.1%) were below 40 years of age. 43 (61.4%) patients were in stage II TBM. The mean duration of illness was 77 ± 101.9 days. Majority of patients presented with fever (94.3%), headache (90%) and vomiting (84.3%). MRI was abnormal at baseline in 67 (95.7%) of patients, most common abnormalities being meningeal enhancement (68.6%) and tuberculomas (57.1%). PET was abnormal in 66 (95.7%) of patients. All these patients had either lung lesions (n = 62, 88.6%) or lymphadenopathy (n = 61; 87.1%). 18FDG-PET revealed evidence of brain lesions in 52 (74.3%) patients. It revealed vertebral involvement in 19 (27.1%) and genitourinary lesions in 9 (12.9%) patients. PET evidence of lymphadenopathy correlated significantly (p = .04) with good outcome in CNS TB.Conclusion18FDG-PET does seem to have a promising role in initial evaluation of patients with CNS TB.

Epilepsy and neuropsychiatric comorbidities in mice carrying a recurrent Dravet syndrome SCN1A missense mutation

Dravet Syndrome (DS) is an encephalopathy with epilepsy associated with multiple neuropsychiatric comorbidities. In up to 90% of cases, it is caused by functional happloinsufficiency of the SCN1A gene, which encodes the alpha subunit of a voltage-dependent sodium channel (Nav1.1). Preclinical development of new targeted therapies requires accessible animal models which recapitulate the disease at the genetic and clinical levels. Here we describe that a C57BL/6 J knock-in mouse strain carrying a heterozygous, clinically relevant SCN1A mutation (A1783V) presents a full spectrum of DS manifestations. This includes 70% mortality rate during the first 8 weeks of age, reduced threshold for heat-induced seizures (4.7 °C lower compared with control littermates), cognitive impairment, motor disturbances, anxiety, hyperactive behavior and defects in the interaction with the environment. In contrast, sociability was relatively preserved. Electrophysiological studies showed spontaneous interictal epileptiform discharges, which increased in a temperature-dependent manner. Seizures were multifocal, with different origins within and across individuals. They showed intra/inter-hemispheric propagation and often resulted in generalized tonic-clonic seizures. 18F-labelled flourodeoxyglucose positron emission tomography (FDG-PET) revealed a global increase in glucose uptake in the brain of Scn1aWT/A1783V mice. We conclude that the Scn1aWT/A1783V model is a robust research platform for the evaluation of new therapies against DS.

Defining imaging biomarker cut points for brain aging and Alzheimer's disease

IntroductionOur goal was to develop cut points for amyloid positron emission tomography (PET), tau PET, flouro-deoxyglucose (FDG) PET, and MRI cortical thickness. MethodsWe examined five methods for determining cut points. ResultsThe reliable worsening method produced a cut point only for amyloid PET. The specificity, sensitivity, and accuracy of cognitively impaired versus young clinically normal (CN) methods labeled the most people abnormal and all gave similar cut points for tau PET, FDG PET, and cortical thickness. Cut points defined using the accuracy of cognitively impaired versus age-matched CN method labeled fewer people abnormal. DiscussionIn the future, we will use a single cut point for amyloid PET (standardized uptake value ratio, 1.42; centiloid, 19) based on the reliable worsening cut point method. We will base lenient cut points for tau PET, FDG PET, and cortical thickness on the accuracy of cognitively impaired versus young CN method and base conservative cut points on the accuracy of cognitively impaired versus age-matched CN method.

Estimation of patient radiation dose from whole body 18F- FDG PET/CT examination in cancer imaging: a preliminary study

This study aims to estimate the radiation effective dose resulting from whole body fluorine-18 flourodeoxyglucose Positron Emission Tomography (18F-FDG PET) scanning as compared to conservative Computed Tomography (CT) techniques in evaluating oncology patients. We reviewed 19 oncology patients who underwent 18F-FDG PET/CT at our centre for cancer staging. Internal and external doses were estimated using radioactivity of injected FDG and volume CT Dose Index (CTDIvol), respectively with employment of the published and modified dose coefficients. The median differences of dose among the conservative CT and PET protocols were determined using Kruskal Wallis test with p < 0.05 considered as significant. The median (interquartile range, IQR) effective doses of non-contrasted CT, contrasted CT and PET scanning protocols were 7.50 (9.35) mSv, 9.76 (3.67) mSv and 6.30 (1.20) mSv, respectively, resulting in the total dose of 21.46 (8.58) mSv. Statistically significant difference was observed in the median effective dose between the three protocols (p < 0.01). The effective doses of whole body 18F-FDG PET technique may be effective the lowest amongst the conventional CT imaging techniques.

Utility of [18F] flourodeoxyglucose positron emission tomography (FDG-PET) to predict resectability after neoadjuvant therapy in patients with unresectable pancreatic cancer on CT scans.

357 Background: The standard imaging approach in patients with pancreatic cancer is contrast enhanced computed tomography (CT), however, Response Evaluation Criteria in Solid Tumors (RECIST) may not be adequate in evaluating response to neoadjuvant therapy. A growing body of evidence exists to suggest that there is additional useful information to be gained from the use of FDG-PET scans in this setting. Methods: We conducted an IRB approved retrospective chart review of patients with locally advanced or borderline resectable pancreatic adenocarcinoma who underwent neoadjuvant therapy at the University of Oklahoma and who had PET/CT imaging before and/or after neoadjuvant therapy between September 2006 and September 2013. Complete remission (CR) was defined as decrease in SUV to ≤ 3.0 or background, and partial response (PR) was defined as decrease in SUV from baseline, but &gt; 3.0. Results: A total of 13 patients underwent Whipple surgery after neoadjuvant therapy at our institution. Four patients (31%) had persistent unresectable disease on CT scans post-neoadjuvant therapy, but demonstrated CR (three patients) or PR (one patient; Pre-treatment SUV: 10.1, Post Treatment: 4.6) on the PET scan. These patients underwent Whipple surgery based on PET response. All four (100%) patients underwent R0 resection. Two patients (50%) received neoadjuvant chemo-radiation in addition to chemotherapy. Conclusions: Response on FDG-PET/CT can be a predictor of R0 resection in cases with evidence of unresectable disease on conventional CT scan. A protocol to study larger number of patients prospectively is being designed.

Dual time point imaging fluorine-18 flourodeoxyglucose positron emission tomography for evaluation of large loco-regional recurrences of breast cancer treated with electrochemotherapy

BackgroundElectrochemotherapy is a local anticancer treatment very efficient for treatment of small cutaneous metastases. The method is now being investigated for large cutaneous recurrences of breast cancer that are often confluent masses of malignant tumour with various degrees of inflammation. To this end 18-Flourine-Flourodeoxyglucose-Positron Emission Tomography/Computed Tomography (FDG-PET/CT) could be a method for response evaluation. However, a standard FDG-PET/CT scan cannot differentiate inflammatory tissue from malignant tissue. Dual point time imaging (DTPI) FDG-PET has the potential of doing so. The purpose of this study was to investigate if DTPI FDG-PET/CT could assess response to electrochemotherapy and to assess the optimal timing of imaging.Patients and methodsWithin a phase II clinical trial 11 patients with cutaneous recurrences had FDG-PET/CT scans at three time points: 60 min, 120 min and 180 min after FDG injection. The scans were performed before and 3 weeks after electrochemotherapy.ResultsA significant reduction in maximum standard uptake value at 60 min post injection was seen after treatment. Furthermore a change in the FDG uptake pattern was observed; from increasing uptake in up to 180 min post injection before treatment to stabilization of FDG uptake at 120 min post injection after treatment. The change in FDG uptake pattern over time lead to change of response in three target lesions; two lesions changed from stable metabolic disease to partial metabolic response and one lesion changed from partial metabolic response to stable metabolic disease. To ensure detection of the change in uptake pattern, scanning 60 and 180 min post injection seems optimal.ConclusionsThe present study shows that FDG-PET/CT 60 and 180 min after tracer injection is a promising tool for response evaluation of cutaneous recurrences of breast cancer treated with electrochemotherapy.

Neither FDG-PET Nor CT Can Distinguish Between a Pathological Complete Response and an Incomplete Response After Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer

To prospectively compare the ability of flourodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) to identify a pathological complete response (pCR) in patients with rectal cancer treated by chemoradiation. A major obstacle in pursuing nonoperative management in patients with rectal cancer after chemoradiation is the inability to identify a pCR preoperatively. A total of 121 patients with rectal cancer were prospectively enrolled. FDG-PET scans and helical CT scans were obtained before and after neoadjuvant chemoradiation. Consensus readings of PET and CT scans were used to classify certainty of disease (5-point confidence rating scale). The ability of PET and CT scans to accurately distinguish a pCR (ypT0) from an incomplete response (ypT1-4) was estimated using the area under the receiver operating characteristic curve (AUC). Of the 121 patients, 26 (21%) had a pCR. PET and CT scans were equally inadequate at distinguishing a pCR from an incomplete response (AUC = 0.64 for both, P = 0.97). Among the 26 patients with a pCR, 14 (54%) and 5 (19%) were classified as complete responders on PET and CT scans, respectively. Among the 95 patients with an incomplete pathological response, 63 (66%) and 90 (95%) were classified as incomplete responders on PET and CT scans, respectively. None of the individual PET parameters, including visual response score, mean standard uptake value (SUVmean), maximum SUV (SUVmax), and total lesion glycolysis, accurately distinguished a pCR (AUCs = 0.57-0.73). Neither PET nor CT scans have adequate predictive value to be clinically useful in distinguishing a pCR from an incomplete response and, therefore, should not be obtained for the purpose of attempting to predict a pCR after neoadjuvant chemoradiation for rectal cancer.

Association between the Alzheimer's disease-related hypometabolic convergence index and clinical ratings in cognitively normal older adults with and without significant fibrillar amyloid burden: Findings from the Alzheimer's Disease Neuroimaging Initiative

We previously developed a voxel-based hypometabolic convergence index (HCI) to characterize, in a single measurement, the extent to which the pattern and magnitude of hypometabolism in a person's flourodeoxyglucose positron emission tomography(FDG PET) image corresponds to that in patients with the clinical diagnosis of Alzheimer's dementia (Chen and Ayutyanont et al., 2010). In this study, we characterized and compared HCIs and their relationship with poorer clinical ratings in cognitively normal “fibrillar Aβ positive and negative” older adults from the Alzheimer's disease Neuroimaging Initiative (ADNI). Florbetapir PET scans from 225 cognitively normal subjects 76±6 years of age were used to characterize mean cortical-to-cerebellar standard uptake value ratios (SUVRs) and classify the images as fibrillar Aβ positive and negative using an SUVR threshold previously found to be associated with moderate or frequent neuritic plaques (Fleisher et al., 2011). FDG PET scans from 71 Aβ positive and 154 Aβ negative subjects were used to generate HCIs, compare this index, and relate them to lower MMSE and higher ADAS-Cog scores (i.e., measures of clinical severity) in the two subject groups. Aβ positive groups had significantly higher HCIs than the Aβ negative groups (p=0.0024). HCIs were significantly associated with poorer MMSE and ADAS-Cog scores in the Aβ positive group (r=-0.38, p=0.001 and r=0.36, p=0.002, respectively) but not in the Aβ negative group (r=0.007, p=0.936 and r=0.06, p=0.458, respectively). Fibrillar A b burden in cognitively normal older adults is associated with an AD-related index of cerebral hypometabolism, and this index is associated with poorer clinical ratings in those who are Aβ positive.

Comparison of nitrate augmented Tc-99m tetrofosmin gated SPECT imaging with FDG PET imaging for the assessment of myocardial viability in patients with severe left ventricular dysfunction

BackgroundOf various nuclear medicine techniques, F-18/flourodeoxyglucose (FDG) positron emission tomography (PET) is considered as the best modality for the assessment of viable myocardium (VM). In this study, we compared the diagnostic accuracy of nitrate augmented Tc-99m tetrofosmin gated G-single-photon emission computed tomography (SPECT) with FDG PET. Methods54 consecutive cases of angiographically proven CAD with severe LV dysfunction were enrolled in the study. The patients underwent Tc-99m tetrofosmin G-SPECT and FDG PET as per the standard protocols and were compared. ResultsSPECT data analysis indicated functional abnormalities in 661/918 myocardial segments. F-18 FDG PET revealed VM in 496/661 segments. The diagnostic accuracy of baseline NAC, postnitrate NAC, baseline AC, and postnitrate AC Tc-99m tetrofosmin SPECT was 84%, 87%, 90%, and 94%, respectively. κ values for NAC baseline, NAC postnitrate, AC baseline, and AC postnitrate Tc-99m tetrofosmin G-SPECT were 0.65, 0.70, 0.77, and 0.85, respectively. Attenuation correction revealed viability additionally in 46 segments which were non-viable on NAC postnitrate study (P < .001). Nitrate augmentation showed viability additionally in 25 segments which were non-viable on AC baseline scan (P = .004). On patient-based analysis FDG PET changes the management only in 13% (7/54) of patients. ConclusionsNitrate augmented AC Tc-99m tetrofosmin G-SPECT shows excellent (κ = .85) agreement with FDG PET. FDG PET changes management only in 13% of the patients. Tc-99m tetrofosmin G-SPECT being more widely available and cheaper imaging modality can be reliably used to detect VM where FDG PET is not available.

Brain imaging biomarkers for the Alzheimer’s Prevention Initiative

Alzheimer's disease (AD), the most common disabling impairment in older adults, takes an unacceptable toll on patients and families. With the growing number of people living to older ages, it is projected to afflict more than 100 million people around the world by 2050. While there is an urgent need, it takes too many cognitively normal (CN) individuals and too many years to evaluate presymptomatic AD treatments using traditional clinical endpoints. We and our colleagues have been using imaging techniques to detect the brain changes associated with the predisposition to AD in CN individuals with 2, 1 and 0 copies of the apolipoprotein E (APOE) e4 allele, the major late-onset AD susceptibility gene, and in CN presenilin 1 (PSEN1) mutation carriers and non-carriers from the world’s largest autosomal dominant early-onset AD kindred in Antioquia, Colombia; we developed several image-analysis techniques and a composite cognitive measure with improved power; and we estimated the sample sizes needed when using these endpoints. We recently proposed the Alzheimer’s Prevention Initiative (API) to help in the effort to launch an era in AD prevention research. The API will include preclinical AD treatment/biomarker development trials in individuals at increased genetic risk for early-onset and late-onset AD, an extremely large Colombian early-onset AD Prevention Registry; and an extremely large North American Alzheimer’s Prevention Registry to support several preclinical AD trials. The API’s first trial will test the anti-amyloid immunization therapy crenezumab in CN PSEN1 mutation carriers using the best established brain imaging and cerebrospinal fluid measurements and our composite cognitive measure as the primary clinical endpoint. It is intended to test an anti-amyloid agent in the preclinical treatment of AD, help determine the extent to which a treatment’s biomarker effects predict a clinical outcome, provide a better test of the amyloid hypothesis, and provide raw data and biological samples to the research community. With support from the U.S. National Institutes of Health, philanthropic funds from the Banner Alzheimer’s Institute, and Genentech, it is also intended to help provide a new paradigm for research collaboration in clinical trials. In this presentation, we will briefly introduce the crucial role of flourodeoxyglucose positron emission tomography (PET), amyloid PET, structural and functional MRI in the preclinical detection, tracking, and treatment of AD. We will present the novel image processing methods we have developed to help in this endeavor, as well as their implementation in the API’s preclinical treatment/biomarker development programs.

Fluorodeoxyglucose positron emission tomography: emerging roles in the evaluation of putative Alzheimer's disease-modifying treatments

Alzheimer's disease (AD) is associated with characteristic and progressive reductions in flourodeoxyglucose positron emission tomography (FDG PET) measurements of the regional cerebral metabolic rate for glucose. These reductions begin years before the onset of symptoms, are correlated with clinical severity, and may help predict an affected patient's clinical course and neuropathological diagnosis. Like several other AD biomarkers, FDG PET has the potential to accelerate the evaluation of AD-modifying treatments, particularly in the earliest clinical and preclinical stages. This article considers FDG PET's role in the detection and tracking of AD, its emerging roles in the evaluation of disease-slowing treatments, some of the issues involved in the acquisition, analysis, and interpretation of FDG PET data, and the evidence needed to help qualify FDG PET and other biomarkers for use in the accelerated approval of AD-slowing treatments. It recommends scientific strategies and public policies to further establish the role of FDG PET and other AD biomarkers in therapeutic trials and find demonstrably effective disease-modifying and presymptomatic AD treatments as quickly as possible.

FDG PET-CT Findings in Epiploic Appendagitis

Abstract:Positron emission tomography (PET) using flourodeoxyglucose (FDG) is routinely used for initial staging and restaging of colorectal cancers. However FDG PET studies can suffer from false-positive tracer uptake due to a variety of physiological and inflammatory conditions arising in the abdo

Sustained attention in patients receiving and abstinent following methadone maintenance treatment for opiate dependence: Performance and neuroimaging results

Objective Impairments in the function of attention exacerbate the course of opiate dependence and may play a role in the relapsing nature of the disorder. This study used clinical measures and positron emission tomography (PET) to assess the functioning of sustained attention in subjects with a history of opiate dependence. Methods A test of auditory sustained attention was administered to 10 subjects receiving methadone maintenance treatment, 13 formerly opiate-dependent subjects in protracted abstinence, and 14 healthy Comparison subjects. Simultaneous measurement of regional glucose metabolism was made by [ 18F] flourodeoxyglucose PET. Subjects groups were compared on the measures of sustained attention and regional cerebral glucose metabolism. Results Healthy Comparison subjects scored significantly better than either methadone-maintained or abstinent former opiate addicts on measures of sustained attention. Formerly opiate-dependent subjects in protracted abstinence scored better than methadone-maintained subjects on sustained attention. Methadone-maintained subjects demonstrated a relative reduction in regional cerebral glucose metabolism in the right supramarginal gyrus, and the thalamus bilaterally. The Comparison subjects without a history of opiate dependence demonstrated a relative increase in regional cerebral glucose metabolism in the right anterior cingulate gyrus, the right medial superior frontal gyrus and the thalamus bilaterally. Conclusions Subjects with a history of opiate dependence have impairments in the functioning of sustained attention, and abnormalities in brain regions identified as important in attention processing. Impairments in attention performance persist in subjects who enjoy prolonged abstinence from opiates.

PET-CT findings in large vessel vasculitis presenting as FUO, a case report

There are increasing data demonstrating the role of flourodeoxyglucose positron emission tomography with computerized tomography fusion ((18)FDG PET-CT) in the diagnosis of large vessel vasculitides, including Takayasu arteritis and giant cell arteritis (Hara et al. 1999; Blockmans et al. 1999; Turlakow et al. 2001]. We report a case of large vessel giant cell arteritis involving the major branches of the aorta as detected on (18)FDG PET-CT. A 56-year-old woman returning to the USA after visiting her native Iraq presented to our rheumatology department with fever of unknown origin (FUO) of 2-month duration, night sweats, and arthralgias. The patient did not have claudication; systolic blood pressure measurements demonstrated a 20-mmHg difference between her arms. Infectious disease, malignancy, and collagen vascular disease workup was unrevealing. Temporal artery and bone marrow biopsies were negative. To exclude FUO of malignancy, (18)FDG PET-CT imaging was performed. The images demonstrated significant (18)FDG uptake (indicating increased metabolic activity) in a circumferential fashion along the aorta and its major braches, including the carotid, subclavian, and common iliac arteries. Contrast-enhanced CT imaging demonstrated wall thickening involving these vessels along with left subclavian vein thrombosis and findings consistent with superficial thrombophlebitis involving the right forearm, wrist, and hand. The combination of laboratory and imaging findings, including the characteristic inflammatory changes involving the large vessel walls as seen on CT, as well as the vessel wall hypermetabolism on FDG PET indicating active inflammation, resulted in the diagnosis of large vessel giant cell arteritis. The patient was treated with high-dose corticosteroids followed by a course of Immuran. Her symptoms resolved and a follow-up FDG PET-CT showed complete resolution of the large vessel hypermetabolism. (18)F-FDG PET-CT can be a useful and noninvasive tool in diagnostic evaluation of FUO by excluding a malignant etiology and providing unexpected information that aids in correct diagnosis.

FDG PET Brain Imaging in Neuropsychiatric Systemic Lupus Erythematosis With Choreic Symptoms

Abstract: Chorea is a rare manifestation of neuropsychiatric systemic lupus erythematosus, and is probably caused by immune-mediated hypofunction of the contralateral striatum. Conventional imaging with brain computed tomography or magnetic resonance imaging often fails to show any structural lesions. We report a case of systemic lupus erythematosus-associated chorea in which brain F-18 flourodeoxyglucose positron emission tomography imaging showed disturbances in striatal metabolism in the absence of structural damage on magnetic resonance imaging. A follow-up positron emission tomography scan showed normalization of striatal metabolism, which was correlated with clinical remission.

Incorporation of functional imaging data in the evaluation of dose distributions using the generalized concept of equivalent uniform dose

Advances in the fields of IMRT and functional imaging have greatly increased the prospect of escalating the dose to highly active or hypoxic tumour sub-volumes and steering the dose away from highly functional critical structure regions. However, current clinical treatment planning and evaluation tools assume homogeneous activity/function status in the tumour/critical structures. A method was developed to incorporate tumour/critical structure heterogeneous functionality in the generalized concept of equivalent uniform dose (EUD). The tumour and critical structures functional EUD (FEUD) values were calculated from the dose–function histogram (DFH), which relates dose to the fraction of total function value at that dose. The DFH incorporates flouro-deoxyglucose positron emission tomography (FDG-PET) functional data for tumour, which describes the distribution of metabolically active tumour clonogens, and single photon emission computed tomography (SPECT) perfusion data for critical structures. To demonstrate the utility of the method, the lung dose distributions of two non-small cell lung caner patients, who received 3D conformal external beam radiotherapy treatment with curative intent, were evaluated. Differences between the calculated lungs EUD and FEUD values of up to 50% were observed in the 3D conformal plans. In addition, a non-small cell lung cancer patient was inversely planned with a target dose prescription of 76 Gy. Two IMRT plans (plan-A and plan-B) were generated for the patient based on the CT, FDG-PET and SPECT treatment planning images using dose–volume objective functions. The IMRT plans were generated with the goal of achieving more critical structures sparing in plan-B than plan-A. Results show the target volume EUD in plan-B is lower than plan-A by 5% with a value of 73.31 Gy, and the FEUD in plan-B is lower than plan-A by 2.6% with a value of 75.77 Gy. The FEUD plan-B values for heart and lungs were lower than plan-A by 22% and 18%, respectively. While EUD values show plan-A is marginally better than plan-B in terms of target volumetric coverage, the FEUD plan-B values show adequate target function coverage with significant critical structure function sparing. In conclusion, incorporating functional data in the calculation of EUD is important in evaluating the biological merit of treatment plans.

The role of FDG-PET scan in staging patients with nonsmall cell carcinoma

Background To assess the role of flourodeoxyglucose–positron-emission tomography (FDG-PET) scan in staging patients with nonsmall cell lung cancer (NSCLC). Methods We prospectively studied 400 patients with NSCLC. Each patient underwent a computed tomography (CT) scan of the chest and upper abdomen, other conventional staging studies and had a FDG-PET scan within 1 month before surgery. All suspicious N2 lymph nodes by either chest CT or by FDG-PET scan were biopsied. Patients that were N2 and M1 negative underwent pulmonary resection and complete thoracic lymphadenectomy. Results The FDG-PET had a higher sensitivity (71% vs 43%, p < 0.001), positive predictive value (44% vs 31%, p < 0.001), negative predictive value (91% vs 84%, p = 0.006), and accuracy (76% vs 68%, p = 0.037) than CT scan for N2 lymph nodes. Similarly, FDG-PET had a higher sensitivity (67% vs 41%, p < 0.001), but lower specificity (78% vs 88%, p = 0.009) than CT scan for N1 lymph nodes. FDG-PET led to unnecessary mediastinoscopy in 38 patients. FDG-PET was most commonly falsely negative in the subcarinal (#7) station and the aortopulmonary window lymph node (#5, #6) stations. It accurately upstaged 28 patients (7%) with unsuspected metastasis and it accurately downstaged 23 patients (6%). Conclusions The FDG-PET scan allows for improved patient selection. It more accurately stages the mediastinum, however there are many false positives lymph nodes and it may be more likely to miss N2 disease in the #5, #6, and #7 stations. A positive FDG-PET scan means a tissue biopsy is indicated in that location.

2030 Positron emission tomography in patients with head and neck carcinoma

To examine the role of positron emission tomography (PET) with labeled flourodeoxyglucose (FDG) in patients with primary neoplasms of the head and neck. Between 9/92 and 9/94, forty-four FDG PET scans were performed on 27 patients with head and neck neoplasms. FDG uptake at the tumor sites was quantified with standardized uptake values (SUV).