Whole-body 18F-fluorodeoxyglucose Positron Emission Tomography Research Articles

Conventional Imaging, MRI and 18F-FDG PET/MRI for N and M Staging in Patients with Newly Diagnosed Breast Cancer.

Background: This study compares the diagnostic potential of conventional staging (computed tomography (CT), axillary sonography and bone scintigraphy), whole-body magnetic resonance imaging (MRI) and whole-body 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/)MRI for N and M staging in newly diagnosed breast cancer. Methods: A total of 208 patients with newly diagnosed breast cancer were prospectively included in this study and underwent contrast-enhanced thoracoabdominal CT, bone scintigraphy and axillary sonography as well as contrast-enhanced whole-body 18F-FDG PET/MRI. The datasets were analyzed with respect to lesion localization and characterization. Histopathology and follow-up imaging served as the reference standard. A McNemar test was used to compare the diagnostic performance of conventional staging, MRI and 18F-FDG PET/MRI and a Wilcoxon test was used to compare differences in true positive findings for nodal staging. Results: Conventional staging determined the N stage with a sensitivity of 80.9%, a specificity of 99.2%, a PPV (positive predictive value) of 98.6% and a NPV (negative predictive value) of 87.4%. The corresponding results for MRI were 79.6%, 100%, 100% and 87.0%, and were 86.5%, 94.1%, 91.7% and 90.3% for 18F-FDG PET/MRI. 18F-FDG PET/MRI was significantly more sensitive in determining malignant lymph nodes than conventional imaging and MRI (p < 0.0001 and p = 0.0005). Furthermore, 18F-FDG PET/MRI accurately estimated the clinical lymph node stage in significantly more cases than conventional imaging and MRI (each p < 0.05). Sensitivity, specificity, PPV and NPV for the M stage in conventional staging were 83.3%, 98.5%, 76.9% and 98.9%, respectively. The corresponding results for both MRI and 18F-FDG PET/MRI were 100.0%, 98.5%, 80.0% and 100.0%. No significant differences between the imaging modalities were seen for the staging of distant metastases. Conclusions:18F-FDG PET/MRI detects lymph node metastases in significantly more patients and estimates clinical lymph node stage more accurately than conventional imaging and MRI. No significant differences were found between imaging modalities with respect to the detection of distant metastases.

Modified signal-to-noise ratio in the liver using the background-to-lung activity ratio to assess image quality of whole-body 18F-fluorodeoxyglucose positron emission tomography.

The signal-to-noise ratio in the liver (SNR liver) is commonly used to assess the quality of positron emission tomography (PET) images; however, it is weakly correlated with visual assessments. Conversely, the noise equivalent count (NEC) density showed a strong correlation with visual assessment but did not consider the effects of image reconstruction conditions. Therefore, we propose a new indicator, the modified SNR liver, and plan to verify its usefulness by comparing it with conventional indicators. We retrospectively analyzed 103 patients who underwent whole-body PET/computed tomography (CT). Approximately 60min after the intravenous injection of 18F-fluorodeoxyglucose (FDG), the participants were scanned for 2min/bed. The SNR liver and NEC density were calculated according to the Japanese guidelines for oncology FDG-PET/CT. The modified SNR live was calculated by multiplying the background-to-lung activity ratio by the SNR liver. Patients were classified into groups based on body mass index (BMI) and visual scores. Subsequently, the relationships between these physical indicators, BMI, and visual scores were evaluated. Although the relationship between the modified SNR liver and BMI was inferior to that of NEC density and BMI, the modified SNR liver distinguished the BMI groups more clearly than the conventional SNR liver. Additionally, the modified SNR liver distinguished low visual scores from high scores more accurately than the conventional SNR liver and NEC density. Whether the modified SNR liver is more suitable than the NEC density remains equivocal; however, the modified SNR liver may be superior to the conventional SNR liver for image-quality assessment.

Is It Possible to Omit Bone Marrow Biopsy in Diagnostic Workup in Patients with Newly Diagnosed Primary CNS Lymphoma? a Retrospective Analysis in the PET/CT Era

Background: Primary central nervous system lymphoma (PCNSL) is a rare and aggressive extra-nodal non-Hodgkin lymphoma (NHL) confined to the brain, eyes, leptomeninges, and spinal cord. More than 90% of patients belong to diffuse large B-cell lymphoma (DLBCL). The consensus around the extensive systematic staging in patients with suspected or proven PCNSL is still a matter of debate. Current diagnostic and staging guidelines recommend extensive workup to exclude systemic disease with computed tomography (CT) scan of the chest, abdomen, and pelvis, a bone marrow biopsy (BMB), and testicular ultrasonography in males. Whole-body 18F-fluorodeoxyglucose positron emission tomography (PET-CT) is currently considered optional in diagnostic workup in patients with presumed PCNSL. The utility of BMB in the era of PET-CT has been challenged in systemic lymphomas, but data are lacking for patients with PCNSL. Among patients with PCNSL, BMB is often normal or reveals low-grade lymphomas or just clonal B-cells. In rare instances, aggressive lymphoma involves both bone marrow (BM) and the central nervous system (CNS). However, the role of BMB in PCNSL patients in the PET-CT era is yet to be established. This study aimed to analyze whether BMB could be safely omitted in the diagnostic workup in patients with PCNSL of DLBCL histology without signs of systemic lymphoma on PET-CT scans. Methods: A comprehensive nationwide retrospective multicenter study with enrollment of patients from the referent medical centers in Denmark for treatment of PCNSL was performed. Patients included in the study were diagnosed between 2002 and 2020 and identified through the Danish Pathology Register. All patients with CNS involvement were potential candidates. Inclusion criteria were the following: 1) patients should be diagnosed with DLBCL in brain, eyes, leptomeninges, cerebrospinal fluid, and spinal cord; 2) have available BMB; and 3) have available PET-CT without signs of lymphoma outside of CNS. Patients with PCNSL and prior history of other lymphoma were also included in the study. Patients were excluded if they were diagnosed with systemic lymphoma or PCNSL other than DLBCL. Patients who did not have PET-CT and BMB performed or in whom this information could not be retrieved through medical records were also excluded from further analysis. Results: Of 1238 potential candidates identified through the Danish pathology register, only 300 patients fulfilled the inclusion criteria. Most patients were excluded due to a lack of information on PET-CT scans and BMB. All included patients had available BMB and no signs of systemic lymphoma on PET-CT. Of the included patients, 252 (84%) were diagnosed with PCNSL without a previous lymphoma diagnosis, while 48 (16%) had a previous history of lymphoma. The median age of patients was 68 years. There was a slight predomination of men (60%) compared to women (40%). Twenty-three (7.7%) patients were found to have discordant findings in BMB. However, none of these showed infiltration with DLBCL. The histologies included various low-grade lymphomas found in 17 patients (5.7%), monoclonal B-cells in 3 patients (1%), and smoldering multiple myeloma in one patient. Conclusion: In this retrospective study of 300 patients with PCNSL with PET-CT scans without signs of systemic lymphoma outside CNS, we found no cases with BM infiltration of DLBCL. A small proportion of patients with PCNSL have a discordant, often low-grade lymphoma in the bone marrow. With a sample size of 300, the chance of overlooking DLBCL infiltration in the BM is ≤ 1 % (95% CI). Therefore, the results of this, so far the most extensive study evaluating BMB in PCNSL in the PET-CT era, suggest that BMB can safely be omitted in patients with PCNSL of DLBCL histology and no signs of systemic lymphoma on PET-CT scans.

Central nervous system mature teratoma producing carbohydrate antigen 19-9: illustrative case.

Central nervous system (CNS) mature teratoma is a rare disease with symptoms that can vary according to tumor location. Most lesions are benign; rarely, malignancy can develop in any of the somatic components. Elevated levels of tumor markers such as α-fetoprotein and β-human chorionic gonadotropin are not usually found in patients with CNS mature teratoma, and no reports have described an association with carbohydrate antigen 19-9 (CA19-9). A 64-year-old woman with headache was found to have a mass lesion in the anterior cranial fossa. Magnetic resonance imaging of the brain suggested a mature teratoma. Serum and cerebrospinal fluid (CSF) tests showed significant CA19-9 elevations (2,770 U/mL and 4,387 U/mL, respectively). Other examinations, including whole-body 18F-fluorodeoxyglucose positron emission tomography, did not detect the origin of elevated CA19-9, suggesting that the high CA19-9 levels were caused by intracranial tumor. The patient underwent tumor removal. The histopathological diagnosis was mature teratoma with positive CA19-9 staining. CA19-9 levels in serum and CSF decreased significantly after tumor removal. The histopathological findings and postoperative decreased CA19-9 levels established the diagnosis of CA19-9-producing CNS mature teratoma. CNS mature teratoma can cause elevations in CA19-9 in cases with absence of neoplasms in the trunk.

MAGIC OF ADVANCED IMAGING AND IMMUNOTHERAPY IN CARDIAC SARCOIDOSIS

TOPIC: Cardiovascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: This case report emphasizes the role of advanced imaging and immunotherapy in the diagnosis and management of cardiac sarcoidosis (CS). CASE PRESENTATION: A 52-year-old healthy male presented with near-syncope for 5 days. He had a blood pressure of 164/67 mmHg and a heart rate of 43 bpm. Electrocardiogram revealed complete-heart-block (CHB) with a ventricular rate of 38/min. Troponin T and electrolytes were normal, and Lyme's serology was negative. Echocardiogram was normal. Cardiac magnetic resonance imaging (CMR) revealed late gadolinium enhancement (LGE) affecting the mid inferior segment at the right ventricle (RV) insertion site (Figure 1). A cardiac and whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scan showed focal areas of increased FDG uptake in the LV involving mid and basal anteroseptal segments, mid inferoseptal segment, basal inferolateral, and basal inferior segments with normal perfusion (Figure 2). The scan also revealed hypermetabolic bilateral hilar and mediastinal lymphadenopathy. A diagnosis of CS was made. An Implantable-Cardioverter-defibrillator (ICD) was placed and the patient was discharged on 40mg of prednisone and 20mg of leflunomide. Within 4 months, he went from 100% RV pacing to 0%. Eventually, the corticosteroid was tapered off. At follow-up after 1.5 years, RV pacing remained 0% on Leflunomide 20mg. DISCUSSION: One should always suspect CS in young patients with high-grade AV block. During the workup of CHB (Figure 3), the 2017 Japanese Circulation Society Working Group Criteria for diagnosing CS was followed (1). The patient had 2 characteristic findings strongly suggestive of sarcoidosis: (a) hilar lymphadenopathy and (b) significant tracer accumulation in the myocardium and hilar lymph nodes on FDG-PET scan. He also met 2 major criteria strongly suggestive of CS: (a) LGE on CMR and (b) abnormal myocardial FDG uptake. These findings, per the criteria, establish the clinical diagnosis of CS. The mainstay of treatment for CS is corticosteroids +/- steroid-sparing agents to decrease intra-cardiac inflammation (1). CHB patients with CS have a high risk of ventricular arrhythmias, hence should receive ICD (2). The addition of antimetabolite adjuvants is more effective than corticosteroids alone (3). They may reduce the total time of glucocorticoid therapy and keep patients in remission. CONCLUSIONS: Clinical diagnosis of CS can be established with FDG-PET imaging and CMR. CS patients with advanced heart block should receive ICD. Corticosteroids are the mainstay of treatment. Immunotherapy is an effective adjunct that can help taper the glucocorticoids and keep patients in remission. Early introduction of these agents should be considered in these patients. REFERENCE #1: 1. Trivieri MG et al. Challenges in Cardiac and Pulmonary Sarcoidosis: JACC State-of-the-Art Review. J Am Coll Cardiol 2020;76:1878-1901 REFERENCE #2: 2. Nordenswan H-K et al. Outcome of Cardiac Sarcoidosis Presenting With High-Grade Atrioventricular Block. Circulation: Arrhythmia and Electrophysiology 2018;11:e006145 REFERENCE #3: 3. Nagai S, Yokomatsu et al. Treatment with methotrexate and low-dose corticosteroids in sarcoidosis patients with cardiac lesions. Intern Med 2014;53:427-33. DISCLOSURES: No relevant relationships by Roy Chung, source=Web Response No relevant relationships by Sachin Kumar, source=Web Response No relevant relationships by Raunak Nair, source=Web Response

The Impact of Metabolic Activity of Vertebra and Amygdala on Stroke Recurrence

Background: We investigated whether the metabolic activities of the vertebrae and amygdala are related to future vascular events after cerebral infarction. Methods: Between August 1, 2015 and February 28, 2020 patients admitted with acute cerebral infarction and carotid atherosclerosis were included. They underwent whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG PET). We compared the FDG uptake in the internal carotid artery, vertebrae, spleen and amygdala between patients with and without stroke recurrence. Cox proportional hazards model was used to identify factors related to stroke recurrence. Findings: A total of 110 stroke patients were included (mean age=73 years, 43 female). During the median follow-up period of 18 months, 15 patients experienced stroke recurrence. Patients with recurrent stroke were more likely to have diabetes mellitus, lower estimated glomerular filtration rate, and a higher degree of internal carotid artery stenosis than in those without. Patients with recurred stroke also had a significantly higher glucose uptake in the vertebrae (1·14±0·28 versus 1·36±0·40, p=0·009 by t-test) and amygdala (1·01±0·11 versus 1·09±0·14, p=0·017) than those without. The vertebral FDG uptake correlated with bone mineral density and C-peptide level. The FDG uptake in the amygdala was correlated with the monocyte lymphocyte ratio, but not with the vertebral FDG uptake. The Cox proportional hazard model showed that a higher FDG uptake in the vertebrae was independently associated with stroke recurrence (hazard ratio=4·94, 95% confidence interval=1·29 – 18·9), and a higher FDG uptake in the amygdala with overall vascular events (hazard ratio=3·11, 95% confidence interval=1·11 – 8·70). Interpretation: The increased metabolic activities of the vertebrae and amygdala are related to stroke recurrence and overall vascular event, possibly by elevated insulin resistance and innate immune response. Funding Statement: The study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF- 2019R1F1A1059455). Declaration of Interests: None. Ethics Approval Statement: This study was reviewed and approved by the institutional review board of Chung-Ang University Hospital (C2015061) and was registered in the Clinical Research Information Service (Registration no.: 170602-001) as a part of the International clinical Trials Registry Platform of the World Health Organization supported by Korea centers for Disease Control and Prevention.

Metabolically Active Subacute Infarct Masquerading as Metastasis: A Finding not to be overlooked in Asymptomatic Oncology Patients.

A 50-year-old man with carcinoma of the right buccal mucosa underwent staging whole-body 18F-fluorodeoxyglucose positron emission tomography–computed tomography, which revealed a hypermetabolic heterogeneously enhancing lobulated primary lesion in the right buccal region and an incidental finding of subacute stroke. The case highlights the importance of discriminating brain neoplasms mimicking stroke from true ischemic stroke, which is crucial for appropriate management of patients in an oncology setting.

Features and clinical impact of extra-cardiac lesions with 18F-fluorodeoxyglucose positron emission tomography in patients with suspected cardiac sarcoidosis.

BackgroundSarcoidosis is a systemic inflammatory disorder and can often affect any other organs beyond the heart. Whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is used to detect not only cardiac but also extra-cardiac involvement of sarcoidosis. However, the features and clinical impact of extra-cardiac lesions have not yet been fully elucidated. Therefore, this study aimed to clarify these using FDG-PET.Methods and resultsWe enrolled 120 consecutive patients with abnormal findings clinically suggesting cardiac sarcoidosis who underwent whole-body FDG-PET. In this study, a patient with suspected cardiac sarcoidosis was defined as one having both clinically suspected findings and FDG-PET positive cardiac uptake. Subsequently, a total of 36 patients with suspected cardiac sarcoidosis were found and analyzed. Extra-cardiac involvement was detected in 35 lesions of 14 patients (39% per patient). In particular, the extra-cardiac lesions were widely distributed throughout the body, and mediastinal/hilar lymph node involvement was most commonly observed. In most of the patients (93% per patient, 13/14), the extra-cardiac lesions were localized in the regions that were considered more accessible with less risk of complication compared with endomyocardial biopsy (EMB). Based on the FDG-PET findings, 8 patients underwent extra-cardiac biopsy without complication, and its diagnostic sensitivity for histological sarcoidosis was high (75%, 6/8). Moreover, FDG-PET-guided extra-cardiac biopsy could confirm histological sarcoidosis in 4 lesions that EMB failed to prove.ConclusionsExtra-cardiac involvement in patients with suspected cardiac sarcoidosis was relatively high. FDG-PET-guided extra-cardiac biopsy may be safe and useful for the imaging based diagnosis of cardiac sarcoidosis.

How common is isolated cardiac sarcoidosis? Extra-cardiac and cardiac findings on clinical examination and whole-body 18F–fluorodeoxyglucose positron emission tomography

BackgroundSarcoidosis is a systemic inflammatory disease which can involve nearly any organ. Clinically manifest cardiac involvement occurs in perhaps 5% of patients with sarcoidosis. The reported prevalence of isolated cardiac sarcoidosis (CS) varies widely with reported rates of 27–54%. The explanation for this variability is likely multi-factorial but perhaps mostly related to the diagnostic method(s) for assessing extra-cardiac involvement. The primary aim of this study was to assess the rate of isolated CS in a homogeneous, prospectively recruited cohort of patients with clinically manifest CS, using whole body FDG PET-CT imaging as a gold standard. A secondary aim was to describe the extent and distribution of extra-cardiac sarcoidosis at the time of first presentation of clinically manifest CS. MethodsPatients were prospectively recruited at the time of first presentation with cardiac symptoms. All patients underwent whole-body and cardiac 18F–FDG PET-CT. All patients were examined for presence of skin sarcoidosis and were assessed by an ophthalmologist. Results31 patients were included (mean age 56±8years, 17 female, 100% Caucasian). Patients had limited extra-cardiac involvement (mean of 2.2 organs) however using the most precise definition, only 1/31 (3.2%) patients had isolated CS. There were marked differences in right ventricular (RV) and atrial involvement between patients presenting with CS as first presentation compared to patients presenting initially with extra-cardiac disease. ConclusionsMost patients had limited extra-cardiac involvement at the time of presentation of manifest CS however, isolated CS, using the proposed gold standard, was only observed in one patient.

Utility of Whole-Body 18F-Fluorodeoxyglucose Positron Emission Tomography to Diagnose Isolated Cardiac Sarcoid

Background: It is reported that up to 25–57% with cardiac sarcoid (CS) may have isolated cardiac sarcoidosis (ICS). The wide variation in prevalence could be related to the diagnostic method(s) for assessing extra–cardiac involvement. Whole-body 18F-fluorodeoxyglucose positron emission tomography computed tomography (18F-FDG PET-CT) imaging may be a useful technique for screening for extra–cardiac involvement in cases of suspected ICS.

Monoarticular carcinomatous knee joint arthritis as an initial presentation of cervical carcinoma

When it comes to cancer, one can expect the unexpected. The clinical presentations can be very bizarre. One of these uncommon presentations is monoarticular arthritis. The age group affected by cancer and arthritis are similar. However, the possibility of joint pain being secondary to metastatic involvement does not come to mind easily. In this report, a 65-year-old postmenopausal woman presented with complaint of pain and restricted movement of the right knee joint, in whom the clinical and magnetic resonance imaging features were suggestive of infective monoarthritis. However, synovial fluid aspirate showed presence of malignant cells. Hence, patient was evaluated with whole-body (18)F-fluorodeoxyglucose positron emission tomography computed tomography which detected primary malignancy of the cervix with regional nodal and right knee joint metastasis. To our knowledge, this is the first reported case of cervical malignancy with solitary skeletal metastasis involving the knee joint. The report also discusses overall incidence of malignant arthritis.

Increased Fdg Uptake in Association with Reduced Extremity Fat in HIV Patients

HIV lipodystrophy - characterized by peripheral lipoatrophy, with or without central fat accumulation - confers increased metabolic risk. However, the functional activity of HIV lipodystrophic tissue in relation to metabolic risk has yet to be fully explored in vivo through the use of non-invasive imaging techniques. This study assesses the relationship between FDG uptake in various fat depots and metabolic/immune parameters among subjects with HIV lipodystrophy. Lipodystrophic men on antiretroviral therapy underwent whole-body (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography scans and detailed metabolic/immune phenotyping. FDG uptake in the subcutaneous adipose tissue (SAT) of the extremities (mean standardized uptake value [SUV] of the arm and leg SAT) was found to correlate with the degree of peripheral lipoatrophy (r=0.7; P=0.01). Extremity SAT FDG uptake was positively associated with homeostasis model assessment of insulin resistance (HOMA-IR; r=0.6; P=0.02) and fasting hyperinsulinaemia (r=0.7; P=0.01), while fat percentage of extremities was not. Furthermore, extremity SAT FDG uptake was significantly associated with CD4(+) T-cell count (r=0.6; P=0.05). In multivariate modelling for HOMA-IR, extremity SAT FDG uptake remained significant after controlling for body mass index and tumour necrosis factor-α (R(2) for model =0.71, P=0.02; SUV in the extremity SAT β-estimate 12.3, P=0.009). In HIV lipodystrophic patients, extremity SAT FDG uptake is increased in association with reduced extremity fat and may contribute to insulin resistance. Non-invasive assessments of in situ inflammation using FDG-PET may usefully complement histological and gene expression analyses of metabolic dysregulation in peripheral fat among HIV-positive patients.

The emerging role of whole-body 18F-fluorodeoxyglucose positron emission tomography in patients with sarcoidosis

IntroductionThe purpose of this article is to examine the emerging role of whole-body positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) in patients with sarcoidosis.Materials and methodsWe reviewed the literature on the use of FDG-PET in patients with sarcoidosis to identify how this technique is being applied in clinical practice.Results and discussionOur review shows that: 1) sarcoidosis is commonly associated with increased FDG uptake. Therefore, positive findings should be interpreted with caution when FDG-PET is being used to distinguish benign from malignant abnormalities; 2) FDG-PET seems to be a very useful molecular imaging method for staging sarcoidosis, identification of occult sites of involvement, guiding biopsy procedures, and monitoring patients’ responses to treatment; and 3) in patients with sarcoidosis, the diagnostic accuracy of FDG-PET is superior to that of 67Ga scintigraphy.

The efficacy of whole-body FDG-PET or PET/CT for autoimmune pancreatitis and associated extrapancreatic autoimmune lesions

The aim of this study was to evaluate retrospectively the efficacy of whole-body (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) for autoimmune pancreatitis (AIP) and associated extrapancreatic autoimmune lesions. Whole-body FDG-PET or PET/computed tomography (CT) findings were reviewed in six patients with AIP. The initial PET scans were performed 1 h and 2 h after FDG injection in all six patients. Follow-up PET scans were performed during or following steroid therapy in five patients and in one patient who did not have steroid therapy. The initial PET scans revealed intense FDG uptake by AIP in all six patients. The maximum standardized uptake value (SUVmax) increased in four patients and was stable in two patients. The intense uptake in the pancreas disappeared during or following steroid therapy in five patients and in one patient who showed spontaneous remission of AIP. Abnormal FDG uptake by extrapancreatic autoimmune diseases was observed in five of the six patients: sclerosing sialadenitis (n = 5), lymphadenopathy (n = 5), retroperitoneal fibrosis (n = 2), interstitial nephritis (n = 2) and sclerosing cholecystitis (n = 1). Abnormal FDG uptake disappeared in the salivary glands (n = 4), lymph nodes (n = 4), retroperitoneum (n = 2), kidneys (n = 1) and gallbladder (n = 1) during or following steroid therapy and remained in the salivary glands and lymph nodes of a spontaneous remission patient. These results suggest that whole-body FDG-PET may be useful for detecting AIP and associated extrapancreatic autoimmune lesions and for monitoring their disease activity but that dual time point imaging may not be useful for differentiating malignancy from AIP.

Cancer screening of healthy volunteers using whole-body 18F-FDG-PET scans: The Nishidai clinic study

In order to evaluate the diagnostic performance of cancer screening using whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scanning for asymptomatic subjects, we conducted a historical cohort study. The study group comprised 5807 individuals who underwent PET scanning from 2002 to 2003. Each subject had carried out a procedure with whole-body 18F-FDG-PET scan with some other diagnostic tests. Out of 5807 participants, data from 4881 subjects were analysed. Among them, PET screening revealed abnormal FDG uptake in 562 subjects, and possible or probable malignancy in 324 subjects, and histological diagnosis of cancer in 36 subjects (16 thyroid, seven colon, four lung, five breast, two prostate, and two others) out of them. The overall cancer detection rate was 0.7%, and PET scanning had a sensitivity of 70.6% and a specificity of 94.0%. This result warrants further prospective cohort studies to evaluate the usefulness of PET cancer screening for cancer prevention.

Impact of FDG-PET/MRI Image Fusion on the Detection of Pancreatic Cancer

Background: This study assessed the value of image fusion with ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) in patients suspected of having pancreatic cancer. Methods: 32 patients (12 women, 20 men; age 24–79 years; mean 56.6 years) were included. All patients underwent whole-body FDG-PET examinations and contrast-enhanced MRI. Image fusion used a semiautomatic voxel-based algorithm. Separate reading, side-by-side analysis and evaluation of fused PET/MRI images were performed. Results were correlated to histopathology (n = 30), or clinical follow-up (n = 2). Results: 15/32 patients had pancreas cancer and 17/32 patients benign disease. The sensitivity and specificity for cancer detection by FDG-PET were 93 and 41% for visual and 86 and 58% for semiquantitative analysis whereas MRI achieved 100 and 76% respectively. Topographical assignment of PET foci by image fusion was superior to side-by-side analysis in 11/39 (28%) foci (in 8/32 patients). However, a true impact on therapeutic strategy was observed only in 1/8 patients as the presence of multiple metastases, irresectable primaries or medical reasons for inoperability prevented a curative setting. Conclusion: Compared to side-by-side analysis, PET/MRI image fusion improves the anatomical assignment and interpretation of FDG foci. The therapeutic benefit for the patient however is limited in patients with multiple lesions or incurable primaries.

Comparison of 18F-FDG-PET and standard procedures for the pretreatment staging of children and adolescents with Hodgkin’s disease

The aim of this study was to perform a prospective, blinded comparison of( 18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) and conventional staging methods (CSMs) for initial staging of children and adolescents with Hodgkin's disease (HD). Over a period of 4 years, 55 children and adolescents with HD (mean age 15.5 years, range 3.9-18.9 years) were prospectively recruited into the study. They underwent 61 FDG-PET studies using a dedicated whole-body PET scanner as a part of their initial staging work-up. PET findings were correlated with the results of CSMs, including computed tomography (CT), ultrasound, bone scanning and bone marrow examination. Discordant findings were resolved by magnetic resonance imaging or clinical follow-up (range 2-47 months). PET correctly changed the staging in 15% of patients (seven upstagings, two downstagings). Only two out of 61 patients (3%) were not accurately staged by PET; in these children, PET missed small lymphoma nodules detected on lung CT. The sensitivity of PET and CSMs for pretreatment staging was 96.5% and 87.5%, respectively; specificity was 100% and 60%, and accuracy, 96.7% and 85.2%, respectively. Upon combination of FDG-PET and lung CT, the diagnostic accuracy reached 100% in our series. Our study showed that whole-body FDG-PET is an efficient and useful method for the initial staging of children with HD. FDG-PET in combination with lung CT should be recommended as a screening method prior to other conventional imaging modalities to plan a rational staging protocol. Large multicentre prospective studies are necessary to verify this conclusion.

Fluorodeoxyglucose Positron Emission Tomography in Cutaneous Squamous Cell Carcinoma: Retrospective Analysis of 12 Patients

Background. Whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG PET) has been used for whole-body imaging modality in detecting malignancy in clinical oncology. However, only a few reports of FDG PET in skin cancers have been described, except for melanoma and lymphoma. Objective. To report on the usefulness of FDG PET as a baseline workup study for patients with cutaneous squamous cell carcinoma (SCC). Methods. There were 12 cases of SCC (9 cases with high-risk SCC). Of the 12, FDG PET was performed for staging in 11 patients and for restaging in 1 patient 1 year after wide excision. Results. Primary lesions were detected in nine cases (83.3%), lymph node involvement in three cases (25.0%), and distant organ (lung) involvement in one case (8.3%). In one patient whose primary lesion was positive, stomach cancer with involvement of adrenal glands, omentum, and lymph nodes was incidentally detected. All of the patients with high-risk SCC showed FDG uptakes of the primary lesions, and the patients with FDG uptakes in lymph nodes and distant organ had high-risk SCC. Conclusion. There have been no comparative studies on the cost-effectiveness between sentinel lymph node biopsy and FDG PET in SCC patients. However, considering the noninvasiveness and thoroughness in checking the whole body, including distant organs, FDG PET may have clinical value as a baseline workup study for patients with high-risk SCC. SUNG BIN CHO, MD, WOO GIL CHUNG, MD, MIJIN YUN, MD, JONG DOO LEE, MD, PHD, MIN GEOL LEE, MD, PHD, AND KEE YANG CHUNG, MD, PHD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS.

FDG-PET for preoperative staging of bladder cancer

The presence of lymph node involvement (N) and distant metastasis (M) in patients with invasive bladder carcinoma is a major determinant of survival and, therefore, a pivotal element in the therapeutic management. The aim of this prospective study was to evaluate the use of( 18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in this indication. Whole-body FDG-PET and computed tomography (CT) were performed in 55 patients with non-metastatic invasive bladder cancer for preoperative staging. Correlative imaging of PET with CT was performed, leading to a PET(CT) result. The imaging results were compared with the gold standard, consisting of histopathology (lymphadenectomy, guided biopsy) or clinical follow-up for 12 months, and related to overall survival using the Kaplan-Meier method. The gold standard was available in 40 patients and indicated NM-positive disease in 15 patients (12 N lesions, 8 M lesions), and NM-negative disease in 25 patients. For the diagnosis of NM-positive disease, the sensitivity, specificity and accuracy of PET(CT) were 60%, 88% and 78%, respectively. Diagnostic discordances between PET(CT) and CT alone were found in 9/40 patients, among whom PET was correct in six (15%): three with true-positive and one with true-negative distant metastases, and two with true-negative lymph nodes. Median survival time of patients in whom PET(CT) indicated NM-positive disease was 13.5 months, compared with 32.0 months in the patients with a NM-negative PET(CT) (p=0.003). Addition of metabolism-based information provided by FDG-PET to CT in the preoperative staging of invasive bladder carcinoma yields a high diagnostic and prognostic accuracy.

Positron emission tomography with selected mediastinoscopy compared to routine mediastinoscopy offers cost and clinical outcome benefits for pre-operative staging of non-small cell lung cancer

(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging is an important staging procedure in patients with non-small cell lung cancer (NSCLC). We aimed to demonstrate, through a decision tree model and the incorporation of real costs of each component, that routine FDG-PET imaging as a prelude to curative surgery will reduce requirements for routine mediastinoscopy and overall hospital costs. A decision tree model comparing routine whole-body FDG-PET imaging to routine staging mediastinoscopy was used, with baseline variables of sensitivity, specificity and prevalence of non-operable and metastatic disease obtained from institutional data and a literature review. Costings for hospital admissions for mediastinoscopy and thoracotomy of actual patients with NSCLC were determined. The overall and average cost of managing patients was then calculated over a range of FDG-PET costs to derive projected cost savings to the community. The prevalence of histologically proven mediastinal involvement in patients with NSCLC presenting for surgical assessment at our institution is 20%, and the prevalence of distant metastatic disease is 6%. Based on literature review, the pooled sensitivity and specificity of FDG-PET for detection of mediastinal spread are 84% and 89% respectively, and for mediastinoscopy, 81% and 100%. The average cost of mediastinoscopy for NSCLC in our institution is 4,160 AUD, while that of thoracotomy is 15,642 AUD. The cost of an FDG-PET scan is estimated to be 1,500 AUD. Using these figures and the decision tree model, the average cost saving is 2,128 AUDper patient. Routine FDG-PET scanning with selective mediastinoscopy will save 2,128 AUD per patient and will potentially reduce inappropriate surgery. These cost savings remain robust over a wide range of disease prevalence and FDG-PET costs.