FDG-PET Findings Research Articles

Use of FDG PET as an Imaging Biomarker in Clinical Trials of Alzheimer’s Disease

PET with the glucose analog FDG as a tracer is a mature and increasingly available clinical imaging technique that can improve the diagnostic accuracy for Alzheimer's disease, which is of particular value at an early stage of the disease when clinical symptoms are still mild and nonspecific. It can also monitor progression of Alzheimer's disease, and the findings are closely related to clinical symptoms. FDG PET, therefore, could also potentially be used as an imaging biomarker for selection of patients and assessment of outcome in clinical trials. Several published intervention studies indicate a good correspondence between clinical outcome and FDG PET findings, but study designs and methods used for data analysis vary widely. Recent developments towards standardization of largely user-independent methods for quantification of regional metabolic impairment on FDG PET scans will allow a new generation of studies that could provide the required evidence for full qualification of FDG PET as an imaging biomarker in clinical trials.

The diagnostic value of FDG–PET cannot be judged by iliac bone marrow biopsy

The Editor, We read with great interest a recent publication by Muzahir et al [1] on the value of 18-fludeoxyglucose–positron emission tomography (FDG–PET)/CT in the detection of bone marrow involvement (BMI) in Hodgkin’s lymphoma (HL). However, we cannot agree with the authors on the definition of BMI. We believe that the data were not reliable because the authors defined a positive bone marrow lesion based solely on a positive finding on iliac bone marrow biopsy (BMB), and because the authors regarded diffuse FDG uptake in bone marrow as a positive PET finding. BMB is traditionally performed in the iliac crests. When the technique was first advocated, it was not known which part of the bone marrow would have tumour infiltration; the iliac crest was chosen because of its convenient location and richness of bone marrow. BMB performed in this way has a high false-negative rate and cannot accurately reflect the status of lymphoma in the bone marrow. Many pathological studies have proven that blind iliac BMB has a low sensitivity for detecting BMI lesions in various malignancies [2]. The fact that a unilateral iliac BMB missed 26–50% of BMI cases in lymphoma patients (based on the findings of bilateral iliac BMB) [3-6] provided strong evidence that a significant number of BMI lesions would be missed even if a bilateral iliac BMB was performed. In addition, multiple studies revealed that FDG–PET or PET/CT detects more BMI than iliac BMB [7-12]. BMI typically manifests as multifocal FDG abnormalities on FDG–PET imaging [9,10,12]. Multifocal lesions on an FDG–PET scan are often indicated as true-positive BMI if other conditions (fractures, osteomyelitis etc.) can be ruled out, even if BMB (performed blindly in the iliac crests) is negative. This often indicates a false-negative finding for BMB, owing to the fact that if a repeat BMB was performed at the bone region where abnormal FDG uptake is noticed, BMB would very likely be positive for BMI [10,13,14]. Using the BMB finding to judge the FDG–PET finding would render BMI lesions detected with FDG–PET as false-positive findings, leading to a low specificity for FDG–PET and, more importantly, understaging for patients. In addition, taking diffuse FDG uptake in the bone marrow as a positive PET finding in this paper also contributed to the authors’ conclusion that FDG–PET performed poorly. It is well recognised that diffuse FDG uptake in the bone or bone marrow is more likely to be due to inflammatory changes [15] or reactive myeloid hyperplasia [13] than to lymphoma infiltration. Current guidelines have made it clear that diffuse uptake in the bone or bone marrow, even if more intense than in the liver, should not be interpreted as BMI [16,17]. Thus, taking diffuse FDG uptake as a positive finding on PET will lead to a lot of false-positive findings on PET and will decrease the positive predictive value (PPV) of FDG–PET. As a result, we cannot agree with the authors’ conclusion that FDG–PET/CT had a PPV of 29.72% in detecting BMI, which is totally different from our clinical findings and different from other research reports [7-12,14]. Given that the incidence of BMI in Hodgkin’s lymphoma is approximately 20–30%, the PPV of 29.72 for FDG–PET/CT, as this paper reported, essentially means that FDG–PET/CT has no diagnostic value for detecting lymphomatous BMI. This is not consistent with our clinical observation and other research findings, which reported a >90% PPV in a similar clinical setting [7-12].

FDG‐PET guided diagnosis of vaginal intravascular diffuse large B‐cell lymphoma

A 76-year-old woman presented with a 6-month history of progressive bilateral lower limb weakness, anorexia and weight loss and the recent onset of urinary and faecal incontinence with saddle anaesthesia. There was no palpable lymphadenopathy. Urgent magnetic resonance imaging (MRI) ruled out spinal cord or cauda equina compressive lesions. Blood tests showed a raised lactate dehydrogenase (LDH) and erythrocyte sedimentation rate with an IgM paraprotein of 7 g/l; immunoglobulins were otherwise normal. Cerebrospinal fluid analysis showed a reactive lymphocytosis on morphology and by flow cytometry. Bilateral bone marrow aspirates and trephine biopsies were normal. Computed tomography (CT) was entirely normal but a repeat MRI with gadolinium showed enhancement of lumbosacral nerve roots suggestive of infiltrative disease. [F]fluorodeoxyglucose (FDG) positron emission tomography (PET) showed diffuse uptake in the uterus, cervix, vagina and numerous groups of lymph nodes throughout the body. The FDG-PET findings led to a vaginal mucosal biopsy, which showed subepithelial capillaries packed with neoplastic lymphoid cells (left) expressing CD20 (right), CD79a and CD5 with a Ki-67 index of 100%; the histological features were those of intravascular diffuse large B-cell lymphoma (DLBCL). At the time of diagnosis the patient had a performance score of 4 and she remained an inpatient. She received twice weekly intrathecal methotrexate, followed by one cycle of CVP (cyclophosphamide, vincristine and prednisolone combination chemotherapy). Rituximab was given 1 week later due to the high risk of tumour lysis syndrome, which has been reported previously. Unfortunately she developed neutropenic sepsis and died 2 weeks after diagnosis. Despite extensive prior investigations it was the results of the FDG-PET scan that eventually guided the biopsy site. The lack of solid lesions makes routine CT and MRI unhelpful in diagnosing this rare subtype of extranodal DLBCL; approximately 50% of patients are diagnosed at autopsy. This case highlights how the nonspecific and diverse symptoms, in the absence of significant lymphadenopathy, can result in critical delays in diagnosing this clinically aggressive lymphoma and how the use of FDG-PET scanning in such patients can guide the biopsy site.

P2‐075: Biomarker correlates in the ADNI Alzheimer's disease dementia population suggesting dementia unlikely due to Alzheimer's

ADNI includes subjects categorized with the clinical diagnosis of probable AD dementia. Data from these subjects has been used as the basis for AD research. Recently, published modifications have been proposed to the clinical diagnostic characterization of AD that for the first time incorporate biomarkers, especially in data used for research. We assessed the ADNI probable AD population to determine if any subjects are included that fit the proposed diagnostic classification of “Dementia unlikely to be due to AD” based on negative Abeta and neuronal injury biomarkers. The ADNI AD dementia population was searched for subjects with FDG PET, MRI and amyloid biomarkers. FDG and adjusted hippocampal volume (HVa) were considered neuronal injury biomarker surrogates. The subgroup was interrogated by searching for FDG findings that were negative for AD. Specifically, FDG patterns were assessed as being “AD-like”, “FTD-like” or “other” by expert blinded readers at the Mayo Clinic using Cortex ID. A HVa cutoff of -0.70cm 3 was used. In addition the sub-population was searched for those who had negative AB biomarkers (CSF and/or Amyloid PET). Eight subjects (8/92 or 9%) were identified that had negative amyloid biomarkers. One had both negative CSF and PiB. FDG PET demonstrated an AD pattern in 3, an FTD pattern in one and an indeterminate pattern in 4. All with usable MRI data (6/8) had abnormal HVa. FDG PET findings with uncharacteristic AD patterns were seen in an additional 27 ADNI AD subjects with positive amyloid studies. HVa was normal in 14 subjects clinically diagnosed with AD dementia with positive amyloid pathology and an AD pattern on FDG. Several subjects within the ADNI AD dementia population fit the recently proposed characterization of “Dementia unlikely to be due to AD” based on both negative Abeta and negative neuronal injury biomarkers (5/92 or 5%). Several others have single biomarker studies that are negative and remain undefined by the new biomarker characterization. These findings are important to consider in research analysis of ADNI AD population data and have important implications with respect to biomarker and clinical diagnostic specificity at an individual patient level.

IC‐P‐145: Biomarker correlates in the ADNI Alzheimer's dementia population suggesting dementia unlikely due to Alzheimer's disease

ADNI includes subjects categorized with the clinical diagnosis of probable AD dementia. Data from these subjects has been used as the basis for AD research. Recently, published modifications have been proposed to the clinical diagnostic characterization of AD that for the first time incorporate biomarkers, especially in data used for research. We assessed the ADNI probable AD population to determine if any subjects are included that fit the proposed diagnostic classification of “Dementia unlikely to be due to AD” based on negative Abeta and neuronal injury biomarkers. The ADNI AD dementia population was searched for subjects with FDG PET, MRI and amyloid biomarkers. FDG and adjusted hippocampal volume (HVa) were considered neuronal injury biomarker surrogates. The subgroup was interrogated by searching for FDG findings that were negative for AD. Specifically, FDG patterns were assessed as being “AD-like”, “FTD-like” or “other” by expert blinded readers at the Mayo Clinic using Cortex ID. A HVa cutoff of -0.70cm 3 was used. In addition the sub-population was searched for those who had negative AB biomarkers (CSF and/or Amyloid PET). Eight subjects (8/92 or 9%) were identified that had negative amyloid biomarkers. One had both negative CSF and PiB. FDG PET demonstrated an AD pattern in 3, an FTD pattern in one and an indeterminate pattern in 4. All with usable MRI data (6/8) had abnormal HVa. FDG PET findings with uncharacteristic AD patterns were seen in an additional 27 ADNI AD subjects with positive amyloid studies. HVa was normal in 14 subjects clinically diagnosed with AD dementia with positive amyloid pathology and an AD pattern on FDG. Several subjects within the ADNI AD dementia population fit the recently proposed characterization of “Dementia unlikely to be due to AD” based on both negative Abeta and negative neuronal injury biomarkers (5/92 or 5%). Several others have single biomarker studies that are negative and remain undefined by the new biomarker characterization. These findings are important to consider in research analysis of ADNI AD population data and have important implications with respect to biomarker and clinical diagnostic specificity at an individual patient level.

P1‐153: Clinical features of Pittsburgh compound‐B–negative dementia

Background/Aims: We previously found that some cases of clinically diagnosed Alzheimer’s disease (AD) were rated as Pittsburgh compound B (PiB) negative by amyloid imaging (i.e. cases of PiB-negative dementia). The present study was designed to analyze the clinical features of PiB-negative dementia patients in detail. Methods: Of the 64 cases of clinically diagnosed AD, 14 were rated PiB negative. Eleven of these were further analyzed using CSF biomarker levels and findings from MRI, FDG-PET, 123I-MIBG myocardial scintigraphy and voxel-based morphometry (VBM). Results: When examined by 123I-MIBG myocardial scintigraphy, the heart/mediastinum ratio was significantly higher in the PiB-negative dementia group than in the dementia with Lewy bodies (DLB) group. Analyses of CSF biomarkers and MRI and FDG-PET findings suggested argyrophilic grain disease (AGD) in 3 cases, frontotemporal lobar degeneration (FTLD) in 3 cases, neurofibrillary tangle-predominant dementia (NFTD) in 1 case, and AD in 2 cases. In the VBM data analysis, the PiB-positive AD group showed significant atrophy of both hippocampi compared with the healthy control group, while the PiB-negative dementia group presented with significant atrophy of the left precuneus. Conclusion: PiB-negative dementia is unlikely to include DLB, while it most likely includes diseases of tauopathy, such as FTLD, AGD and NFTD. A better understanding of PiB-negative dementia is expected to further improve the accuracy of the clinical AD diagnosis.

Erratum to: Two cases of benign esophageal schwannoma with positive FDG-PET findings

Erratum to: Two cases of benign esophageal schwannoma with positive FDG-PET findings

Colorectal Liver Metastasis After 90Y Radioembolization Therapy: Pilot Study of Change in MDCT Attenuation as a Surrogate Marker for Future FDG PET Response

The purpose of this study was to investigate whether changes in attenuation and size of liver metastatic lesions of colorectal cancer at MDCT 1 month after (90)Y radioembolization treatment are predictive of response at FDG PET 3 months after treatment. Twenty patients with colorectal liver metastasis consecutively treated with (90)Y radioembolization underwent triphasic MDCT of the liver at baseline and 1 and 3 months after treatment and FDG PET at baseline and 3 months after treatment. Percentage change in tumor attenuation at MDCT (volumetric attenuation), tumor size at MDCT (according to Response Evaluation Criteria in Solid Tumors [RECIST] and World health Organization [WHO] criteria), and volume-weighted maximum standardized uptake value at FDG PET were evaluated. The correlation between FDG PET response 3 months after treatment and response according to RECIST, WHO criteria, and attenuation 1 month after treatment was evaluated. Only 13.3% of patients with FDG PET findings of response 3 months after treatment were identified according to RECIST and WHO criteria 1 month after treatment. According to attenuation criteria at 1 month, however, 53.3% of patients with an FDG PET response at 3 months were identified. A strong association was found between FDG PET response at 3 months and response based on attenuation criteria (odds ratio, 12.4; 95% CI, 0.58-265.3; p = 0.05). Early changes in the attenuation of liver metastatic lesions of colon cancer after (90)Y radioembolization treatment may be predictive of future response at FDG PET.

Tuberculous lymphadenitis: FDG PET and CT findings in responsive and nonresponsive disease

No data is available on the different FDG PET and CT findings in the lymph nodes (LN) of patients with HIV and tuberculosis (TB) who respond compared with those who do not respond to anti-TB treatment by 4 months after initiation of TB treatment. These findings were the focus of our study. PET/CT scans performed at 4 months after initiation of TB treatment in 20 consecutive HIV patients were analysed. SUVmax values were obtained for all regions of LN involvement. The diameter of the LNs was measured and the CT enhancement (LNs showing peripheral rim enhancement with central low attenuation, PRECLO, in comparison with homogeneously involved LNs) and the calcification patterns of involved LNs assessed. The relationship between the PET and CT findings and the clinical outcome, response or nonresponse, was evaluated. FDG PET identified 91 sites of LN involvement, 20 of which were not identified by CT. SUVmax values were significantly higher in nonresponders (8 patients, SUVmax 11.2 ± 4.0, mean ± SD) when compared to responders (12 patients, SUVmax 2.6 ± 2.3; p = 0.0001). In ROC analysis (AUC 0.952) a cut-off value of 4.5 for SUVmax yielded a sensitivity and specificity of 95% and 85% for discriminating nonresponding from responding LNs. LNs were significantly larger in nonresponders (1.9 ± 0.4 cm) than in responders (1.4 ± 0.4 cm; p = 0.0001); the AUC in the ROC analysis was 0.76. PRECLO LNs were significantly larger (2.2 ± 0.3 cm) than homogeneous involved LN basins (1.5 ± 0.4 cm) and LN basins with calcification (1.4 ± 0.5 cm; p = 0.001). Using the presence of at least one LN basin with PRECLO as a criterion for nonresponse, responders could be separated from nonresponders with a sensitivity of 88% and a specificity of 66%. LNs responding to TB treatment could be differentiated from nonresponding LNs with a sensitivity and specificity of 95% and 85% using a SUVmax cut-off value of 4.5 and a sensitivity and specificity of 88% and 66% using the presence of at least one LN basin with PRECLO.

FDG PET findings leading to diagnosis of neurosarcoidosis

FDG PET findings leading to diagnosis of neurosarcoidosis

Stage-Dependent Agreement between Cerebrospinal Fluid Proteins and FDG-PET Findings in Alzheimer's Disease

Cerebral hypometabolism and abnormal levels of amyloid beta (Aβ), total (t-tau) and phosphorylated tau (ptau) proteins in cerebrospinal fluid (CSF) are established biomarkers of Alzheimer's disease (AD). We examined the agreement between these biomarkers in a single center study of patients with AD of severity extending over a wide range. Forty seven patients (MMSE 21.4 ± 3.6, range 13-28 points) with incipient and probable AD underwent positron emission tomography with [18F]-fluorodeoxyglucose (FDG-PET) and lumbar puncture for CSF assays of Aβ1-42, p-tau181, and t-tau. All findings were classified as either positive or negative for AD. Statistical analyses were performed for the whole sample (n=47) and for the subgroups stratified as mild (MMSE > 20 points, n=30) and moderate (MMSE < 21 points, n=17) AD. In the whole patient sample, the agreement with the FDG-PET finding was 77% (chance-corrected kappa [κ]=0.34, p=0.016) for t-tau, 68% (κ=0.10, n.s.) for p-tau181, and 68% (κ=0.04, n.s.) for Aβ1-42. No significant agreement was found in the mild AD subgroup, while there was a strong agreement for t-tau (94%, κ=0.77, p=0.001) and p-tau181 (88%, κ=0.60, p=0.014) in the moderate AD group. A significant agreement between the FDG-PET and CSF tau findings in patients with AD supports the view that both are markers of neurodegeneration. CSF tau proteins and FDG-PET might substitute each other as supportive diagnostic tools in patients with suspected moderate-to-severe Alzheimer's dementia, while this is not the case in subjects at an earlier disease stage.

Diffuse pulmonary uptake on FDG-PET with normal CT diagnosed as intravascular large B-cell lymphoma: a case report and a discussion of the causes of diffuse FDG uptake in the lungs

A 71-year-old woman was admitted to our hospital with asthenia, weight loss, fever, cognitive impairment and shortness of breath. Physical examination showed hemiparesis and cerebellar ataxia. There was no superficial lymphadenopathy. Blood tests showed raised levels of C-reactive protein and lactate dehydrogenase. Bone marrow aspiration and biopsy were negative. [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) showed intense uptake within a right apical nodule and intense and diffuse uptake of FDG in the lungs without corresponding structural CT abnormality. Lung biopsy showed intravascular large B-cell lymphoma (IVLBCL). FDG-PET findings in IVLBCL and causes of diffuse FDG lung uptake with and without CT abnormalities are discussed.

Detection of Gastroesophageal Reflux Esophagitis Using 2-fluoro-2-deoxy-d-glucose Positron Emission Tomography

Background. Gastroesophageal reflux disease (GERD) is a common disease and a major upper gastrointestinal problem. The purpose of the present study is to evaluate the use of noninvasive 2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) to detect gastroesophageal reflux esophagitis. Materials and Methods. This is a retrospective study reviewing 408 healthy check-up subjects (169 females and 239 men), who underwent both FDG-PET and upper gastrointestinal endoscopy during September 2008 to December 2009. Quantitative analysis of FDG uptake in the distal part of the esophagus was performed by calculating the maximum standard uptake value (SUVmax). This indicated the degree of esophagitis. FDG-PET findings were compared with endoscopic (modified version of the Los Angeles classification) diagnoses as the gold standard. Results. The SUVmax ranged from 1.30 to 3.40 in normal subjects and from 1.30 to 4.00 in subjects with gastroesophageal reflux esophagitis. In the esophagitis group, the SUVmax was 2.13 ± 0.42 in subjects with modified LA grade M, 2.21 ± 0.45 in subjects with LA grade A, and 2.48 ± 0.44 in subjects with LA grade B and C gastroesophageal reflux esophagitis. One-way ANOVA and post-hoc comparison with Bonferroni correction (P value = 0.003) identified statistical differences between the three groups. Conclusion. Noninvasive FDG-PET may be useful in the detection and evaluation of various degrees of gastroesophageal reflux esophagitis.

Auditory Hallucinations as the Only Presenting Symptom of Right-Parietal Spontaneous Hemorrhage: FDG-PET Evidence of Corpus Callosum Hyperactivity

Back to table of contents Previous article Next article LettersFull AccessAuditory Hallucinations as the Only Presenting Symptom of Right-Parietal Spontaneous Hemorrhage: FDG-PET Evidence of Corpus Callosum HyperactivityMassimiliano Godani, M.D., Andrea Ciarmiello, M.D., Cesare Capellini, M.D., and Massimo Del Sette, M.D.Massimiliano GodaniSearch for more papers by this author, M.D., Andrea CiarmielloSearch for more papers by this author, M.D., Cesare CapelliniSearch for more papers by this author, M.D., and Massimo Del SetteSearch for more papers by this author, M.D.Published Online:1 Jan 2012https://doi.org/10.1176/appi.neuropsych.11020054AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor: Auditory hallucinations are very rare in stroke patients. We report FDG-PET findings in a case of hemorrhagic stroke presenting with auditory hallucinations.Case ReportA 67-year-old woman was admitted to the emergency room of our hospital for acute onset of complex auditory hallucinations; she reported hearing loud music and voices of known persons speaking “filthy.” She had never suffered any psychiatric disorders in the past, and she was taking atenolol for many years as the only treatment for chronic arterial hypertension.Neurological examination did not show any focal neurological signs, and blood tests were normal. Brain CT scan revealed a right-parietal hemorrhage involving both superficial and deep territory of the posterior branches of middle cerebral artery (Figure 1 [D]). EEG showed absence of focal paroxystic epyleptiform discharges. Brain MRI and MR-angio confirmed the intraparenchimal hemorrhage, excluding the presence of aneurysm or artero-venous malformations. FDG-PET scan showed a significant increase in glucose metabolism (versus normal control database) in the middle and posterior areas of corpus callosum as well as in the precuneus and cuneus cortex (Figure 1 [A, B, C]).The auditory hallucinations gradually resolved in a few days without any treatment. She was discharged after 18 days from onset, and neurological examination showed visuospatial deficit as the consequence of right-parietal damage.DiscussionAuditory hallucinations are uncommon phenomena in patients with acute stroke; in particular, they have been reported in acute ischemic lesions of the brainstem but very rarely reported after cortical ischemic strokes.1 To our knowledge, this is the first case of auditory hallucinations as the only presenting symptom of a spontaneous hypertensive parenchymal hemmorrhage.In our case FDG-PET scan showed high relative glucose metabolic rates in the middle and posterior areas of corpus callosum. Hyperactivity of corpus callosum has already been reported in schizophrenic patients with auditory hallucinations.2,3 In particular, abnormalities in the posterior part of corpus callosum has been associated to schizophrenic positive symptoms.4 We speculate that in our patient the acute cortico-subcortical hemorrhage caused, through rapid development of peri-lesional edema and release of excitatory mediators such as calcium ions and amino-acids, an electrode-like effect,5 which abnormally activated the posterior part of corpus callosum, with consequent development of auditory hallucinations. We believe that a better understanding of corpus callosum pathophysiology could help in clarifying the mechanism of perceptive disturbances of various origin.Neurology UnitS. Andrea HospitalLA Spezia, ItalyCorrespondence: Massimiliano Godani, M.D.; massimiliano.[email protected]liguria.it1. Yair L , Mordechai L , Ronit G, et al.: Auditory hallucinations in acute stroke. Behav Neurol 2005; 16:211–216Crossref, Medline, Google Scholar2. Buchsbaum MS , Buchsbaum BR , Hazlett EA, et al.: Relative glucose metabolic rate higher in white matter in patients with schizophrenia. Am J Psychiatry 2007; 164:1072–1081Crossref, Medline, Google Scholar3. Hubl D , Koenig T , Strik W, et al.: Pathways that make voices. Arch Gen Psychiatry 2004; 61:658–668Crossref, Medline, Google Scholar4. Kubicki M , Styner M , Bouix S, et al.: Reduced interhemispheric connectivity in schizophrenia: tractography base segmentation of the corpus callosum. Schizophr Res 2008; 106(2–3):125–131Crossref, Medline, Google Scholar5. Weber B , Fouad K , Burger C, et al.: White-matter glucose metabolism during intracortical electrostimulation: a quantitative fluorodeoxyglucose autoradiography study in the rat. Neuroimage 2002; 16:993–998Crossref, Medline, Google Scholar FiguresReferencesCited byDetailsCited byJournal of the Neurological Sciences, Vol. 398Frontiers in Psychiatry, Vol. 8PET and SPECT Findings in Patients with Hallucinations29 January 2014 Volume 24Issue 1 Winter 2012Pages E28-E29 Metrics PDF download History Published online 1 January 2012 Published in print 1 January 2012

Meta-analysis of the diagnostic performance of [18F]FDG-PET and PET/CT in renal cell carcinoma

Objectives: Positron emission tomography (PET) using fluorodeoxyglucose (FDG) is useful for restaging renal cell carcinoma (RCC) and detecting metastatic diseases but is less satisfactory for detecting primary disease. We evaluated whether the integration of computed tomography (CT) scans with the PET system could increase the applicability of FDG-PET for RCC. Methods: The MEDLINE databases were searched for relevant studies published since 2001. Two reviewers independently assessed the methodological quality of each study identified. We then performed a meta-analysis of the sensitivity and specificity of FDG-PET findings as reported in all the selected studies. Results: Fourteen studies were eligible for inclusion. The pooled sensitivity and specificity of FDG-PET were 62% and 88% respectively, for renal lesions. For detecting extra-renal lesions, the pooled sensitivity and specificity of FDG-PET were 79% and 90%, respectively, based on the scans, and 84% and 91% based on the lesions. The use of a hybrid FDG-PET/CT to detect extra-renal lesions increased the pooled sensitivity and specificity to 91% and 88%, respectively, with good consistency. Conclusions: For RCC, combining the FDG-PET and CT systems is helpful for detecting extra-renal metastasis rather than renal lesions. The hybrid PET/CT system has comparable sensitivity and specificity with PET in detecting extra-renal lesions of RCC. Advances in knowledge: The FDG-PET and PET/CT systems are both useful for detecting extra-renal metastasis in renal cell carcinoma.

No Place Like Home? Outpatient Management of Patients With Febrile Neutropenia and Low Risk

and positron emission tomography in patients with metastatic gastrointestinal stromal tumor treated at a single institution with imatinib mesylate: Proposal of new computed tomography response criteria. J Clin Oncol 25:1753-1759, 2007 45. Choi H, Charnsangavej C, de Castro Faria S, et al: CT evaluation of the response of gastrointestinal stromal tumors after imatinib mesylate treatment: A quantitative analysis correlated with FDG PET findings. AJR Am J Roentgenol 183:1619-1628, 2004 46. Lencioni R, Llovet JM: Modified RECIST (mRECIST) assessment for hepatocellular carcinoma. Semin Liver Dis 30:52-60, 2010 47. Abou-Alfa GK, Schwartz L, Ricci S, et al: Phase II study of sorafenib in patients with advanced hepatocellular carcinoma. J Clin Oncol 24:4293-4300, 2006 48. Abou-Alfa GK, Zhao B, Capanu M, et al: Tumor necrosis as a correlate for response in subgroup of patients with advanced hepatocellular carcinoma (HCC) treated with sorafenib. ESMO 2008, Stockholm, Sweden. Ann Oncol 19:viii178, 2008 (suppl 8; abstr 547P)

An Unusual Unilocular Mesothelial Cyst of the Pleura

A 79-year-old woman was found to have an abnormal shadow on chest radiography. Computed tomography demonstrated a pleural mass. The F-18 fluorodeoxyglucose positron emission tomography (FDG PET) was performed to determine whether the pleural mass was benign or malignant. The histologic examination of the resected mass showed a unilocular mesothelial cyst of the pleura. The FDG PET findings of a mesothelial cyst of the pleura have not yet been previously reported. The FDG PET findings of a mesothelial cyst in the pleura reflected the microscopic findings of the resected mass. The FDG PET findings, therefore, seem to be useful in the diagnosis of mesothelial cysts.

Early prediction of clinical response to first-line treatment with gefitinib using integrated FDG-PET for patients with advanced non-small cell lung cancer.

e18049 Background: Early prediction of clinical response is of great value in patients with advanced non-small cell lung cancer (NSCLC) in avoiding unnecessary toxicity and giving them another chance for different treatment. This study aimed to assess the integrated 18-fluorodeoxyglucose positron emission tomography (FDG-PET) at 3 days after treatment as a tool for early response predictor in the patients treated with gefitinib or carboplatin plus paclitaxel (CP). Methods: Patients with stage IIIB or IV NSCLC were scheduled to receive first-line treatment were eligible for this study. Patients were treated with gefitinib (250mg) once daily or with CP every 3-week cycle as first-line treatment. FDG-PET was performed before and 3 day after initiation of each treatment. Based on previous studies, a reduction of tumor FDG uptake was assessed by using standardized uptake value (SUV). ROC analyses were performed to compare the results of the visually interpreted FDG-PET findings and the findings obtained with the use of an SUV threshold. Results: A total 38 patients were included in this study. Nineteen patients (50%) received gefitinib, and 19 (50%) received CP. The overall response rate (RR) was 36% with 7 partial response (PR) in gefitinig group and 16% with 3 PR in CP group. The optimal differentiation achieved by a cut-off value in reduction of SUV level was 20% in gefitinib group and 15% in CPgroup. Applying this cut-off value as a criterion for a metabolic response, sensitivity and specificity for predicted clinical response was of 91% and 100% in patients with gefitinib, 81% and 67% in patients with CP, respectively. , Metabolic responder had significant longer survival than non-responder in gefitinib group (median overall survival (OS): 22.6m, 95%CI: 7.4-37.8 vs median OS: 7.7m, 95%CI: 1.7-13.7, p=0.04), while there was no correlation between a reduction of SUV level and OS in CP group (median OS: 13.9m, 95%CI: 10.0-17.8 vs median OS: 10.5m, 95%CI: 7.3-13.7, p=0.56). Conclusions: The reduction of SUV level by using FDG-PET at 3 day after treatment can predict response and survival in gefitinib-treated patients.

F-18 FDG PET/CT in Evaluation of Pulmonary Sclerosing Hemangioma

Pulmonary sclerosing hemangioma (PSH), or the alternative name of "sclerosing pneumocytoma," is a rare benign neoplasm. PSH is often asymptomatic and presents as a solitary pulmonary nodule on radiologic imaging studies. Few articles have been reported to describe the FDG PET findings about PSH. We reported FDG PET findings of 6 cases of PSH and reviewed the literatures. FDG PET and PET/CT imaging studies of 6 patients with proven PSH were reviewed. The relation between the degree of FDG uptake and tumor size was analyzed. All 6 tumors were detected by FDG PET or PET/CT. Mean diameter of these tumors was 2.9 cm. Mean standard uptake value was 2.45 (range, 1.8-3.93). The maximal standard uptake value of FDG uptake was positively correlated with the tumor size (R = 0.9694, P < 0.05). PSH demonstrates low to moderate uptake on FDG PET imaging. The larger PSH has higher uptake and might be misrecognized as a malignancy. The possibility of false-positive result caused by PSH should be considered while interpreting FDG PET images of solitary pulmonary nodules.

The F-18 FDG PET Findings of a Thymic Infarct in a Patient With Acute Chest Pain

The F-18 FDG PET Findings of a Thymic Infarct in a Patient With Acute Chest Pain