Uptake In Mediastinal Nodes Research Articles

A machine learning tool to improve prediction of mediastinal lymph node metastases in non-small cell lung cancer using routinely obtainable [18F]FDG-PET/CT parameters

BackgroundIn patients with non-small cell lung cancer (NSCLC), accuracy of [18F]FDG-PET/CT for pretherapeutic lymph node (LN) staging is limited by false positive findings. Our aim was to evaluate machine learning with routinely obtainable variables to improve accuracy over standard visual image assessment.MethodsMonocentric retrospective analysis of pretherapeutic [18F]FDG-PET/CT in 491 consecutive patients with NSCLC using an analog PET/CT scanner (training + test cohort, n = 385) or digital scanner (validation, n = 106). Forty clinical variables, tumor characteristics, and image variables (e.g., primary tumor and LN SUVmax and size) were collected. Different combinations of machine learning methods for feature selection and classification of N0/1 vs. N2/3 disease were compared. Ten-fold nested cross-validation was used to derive the mean area under the ROC curve of the ten test folds (“test AUC”) and AUC in the validation cohort. Reference standard was the final N stage from interdisciplinary consensus (histological results for N2/3 LNs in 96%).ResultsN2/3 disease was present in 190 patients (39%; training + test, 37%; validation, 46%; p = 0.09). A gradient boosting classifier (GBM) with 10 features was selected as the final model based on test AUC of 0.91 (95% confidence interval, 0.87–0.94). Validation AUC was 0.94 (0.89–0.98). At a target sensitivity of approx. 90%, test/validation accuracy of the GBM was 0.78/0.87. This was significantly higher than the accuracy based on “mediastinal LN uptake > mediastinum” (0.7/0.75; each p < 0.05) or combined PET/CT criteria (PET positive and/or LN short axis diameter > 10 mm; 0.68/0.75; each p < 0.001). Harmonization of PET images between the two scanners affected SUVmax and visual assessment of the LNs but did not diminish the AUC of the GBM.ConclusionsA machine learning model based on routinely available variables from [18F]FDG-PET/CT improved accuracy in mediastinal LN staging compared to established visual assessment criteria. A web application implementing this model was made available.

LYMPH NODE UPSTAGING AFTER SURGERY IN PATIENTS WITH NEGATIVE MEDIASTINAL STAGING BY EBUS.

Mediastinal staging is a hot topic in thoracic oncology. According to the guidelines, and besides other criteria, in the presence of a primary lung cancer with increased mediastinal lymph node uptake on PET-CT, a negative result after lymph node sampling by Endobronchial Ultrasound (EBUS) is not enough to rule out mediastinal lymph node involve- ment, demanding a cervical mediastinoscopy to vouch for the results. In order to study the percentage of lymph node surgical upstaging in patients with neg- ative mediastinal node staging by EBUS and evaluate the role of mediastinoscopy in these patients, we conducted a search in our department's database using the key-word EBUS in the period concerned between January 2014 and August 2020. A total of 302 patients were found. After applying defined criteria, we obtained 42 cases. Lymph node surgical upstaging occurred in 11 (26%) patients, of which 8 were upstaged to N2 and 3 to N1. Most of the cases were single station. Only in 5 (12% of the total) of the 11 patients, the upstaging was related to lymph node stations previously sampled by EBUS. Upstaging was more frequent among males and lower lobe tumours. Regarding the 8 upstage cases for N2, 5 were single station. Of these 8 cases, only 5 would be approachable by cervical mediastinoscopy. Furthermore, 2 of them were single station, eligible for upfront surgery. Then, only in 3 (7%) of the 42 cases cervical mediastinoscopy would be of foremost importance.

Mediastinoskopi: Küçük Hücreli Dışı Akciğer Kanseri N-Evrelemesinde Hala Geçerli Mi Yoksa Değersiz Bir Yöntem Midir?

This study compares the two most frequently used methods, combined positron emission tomography-computed tomography (PET/CT) and mediastinoscopy, in detecting mediastinal lymph node metastases. It has been investigated whether PET/CT can be used as an alternative method to mediastinoscopy which is considered the gold standard in detecting mediastinal lymph node metastasis. Mediastinal lymph node metastasis is an important factor in treatment and prognosis of non-small cell lung cancer. A total of 102 patients diagnosed with non-small cell lung cancer by our clinic between 2012 and 2017, were enrolled in the study. In total 277 lymph nodes were compared with respect to their histopathologic results and their involvement in positron emission tomography. Specificity value of PET/CT was detected as 84.5% while its negative predictive value, positive predictive value and sensitivity were 82.7%, 69.5% and 66.6%, respectively. In patients who underwent only mediastinoscopy and whose frozen section samples did not demonstrate any metastatic involvement, when histopathological results of lymph node dissection performed by thoracotomy were analyzed, the negative predictive value of mediastinoscopy was calculated as 97%. In total 65 stations including 46 stations smaller than 1 centimeter and 19 stations larger than 1 centimeter, which did not demonstrate any uptake in PET/CT, were sampled. No metastasis was detected in histopathologic staging of these lymph nodes. For patients who do not demonstrate any uptake in mediastinal lymph nodes on PET/CT, invasive lymph node sampling is redundant. However, with the aim of avoiding unnecessary thoracotomies, invasive lymph node sampling is required, even though mediastinal lymph node uptake detected with PET/CT is below the threshold of malignancy.

18-FDG-PET in a patient cohort suspected for cardiac sarcoidosis: Right ventricular uptake is associated with pathological uptake in mediastinal lymph nodes

IntroductionIn up to 65% of cardiac sarcoidosis patients, the disease is confined to the heart. Diagnosing isolated cardiac sarcoidosis is challenging due to the low sensitivity of endomyocardial biopsy. If cardiac sarcoidosis is part of biopsy-confirmed systemic sarcoidosis, the diagnosis can be based on cardiac imaging studies. We compared the imaging features of patients with isolated cardiac FDG uptake on positron emission tomography with those who had findings indicative of systemic sarcoidosis. Materials and methods137 consecutive cardiac FDG-PET/CT studies performed on subjects suspected of having cardiac sarcoidosis were retrospectively analyzed. Results33 patients had pathological left ventricular FDG uptake, and 12 of these also had pathological right ventricular uptake. 16/33 patients with pathological cardiac uptake had pathological extracardiac uptake. 10/12 patients with both LV- and RV-uptake patterns had extracardiac uptake compared to 6/21 of those with pathological LV uptake without RV uptake. SUVmax values in the myocardium were higher among patients with abnormal extracardiac uptake. The presence of extracardiac uptake was the only imaging-related factor that could predict a biopsy indicative of sarcoidosis. ConclusionRight ventricular involvement seems to be more common in patients who also have findings suggestive of suspected systemic sarcoidosis, compared with patients with PET findings indicative of isolated cardiac disease.

Prognostic significance of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography-derived metabolic parameters in surgically resected clinical-N0 nonsmall cell lung cancer.

Our aim was to assess the significance of metabolic positron emission tomography (PET) parameters for the prediction of occult mediastinal lymph node metastasis (OLM) and recurrence in patients with clinical-N0 nonsmall cell lung cancer (NSCLC) after surgical resection and lymph node dissection. We evaluated 98 patients with NSCLC [52 adenocarcinoma (ADC), 46 squamous cell carcinoma (SQCC)] who had undergone initial/preoperative fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT). Eligibility criteria for participation were clinically staged as N0 and no FDG uptake in mediastinal lymph nodes on preoperative PET/CT. Clinicopathological characteristics and the diagnosis of recurrence were obtained by reviewing the hospital records. Metabolic parameters [maximum standardized uptake value, mean standardized uptake value, metabolic tumor volume (MTV), total lesion glycolysis] were determined on F-FDG PET/CT images. The association of metabolic parameters with OLM and recurrence was assessed. OLM was found in 26 (26.53%) patients. T-stage, central location, and lymphovascular invasion were associated with OLM (respectively, P=0.007, 0.011, <0.001). None of the metabolic parameters was associated with OLM. Metabolic parameters of the tumor were significantly higher in patients with recurrence when the cohort was evaluated as a whole (P=0.002, 0.005, 0.016, and 0.004, respectively). In particular, there was a significant association between recurrence and tumor size, grade, stage, MTV (P<0.001), and TLG (P<0.001) in ADC. This association was not found in SQCC. Multivariate analysis showed that MTV was an independent prognostic factor for recurrence and associated with disease-free survival. Metabolic parameters of the primary tumor on preoperative F-FDG PET/CT could not predict OLM in patients with clinical-N0 NSCLC. MTV was an independent risk factor for recurrence in ADC, but not in SQCC.

P1.03-076 Nodal Staging of Patients with Pulmonary Malignancies - The Predictive Value of Different Patterns of Mediastinal 18FDG-PET Activity

In patients with pulmonary malignancies, 18FDG uptake in mediastinal nodes is a sensitive but non-specific indicator of metastatic disease. The pattern of tracer uptake may improve the predictability of such findings. To retrospectively i) compare 18FDG-PET scans and EBUS findings in patients with documented pulmonary malignancies; and, ii) compare the pattern of 18FDG uptake in mediastinal nodes in patients with / without documented mediastinal node metastases. 62 patients with documented pulmonary malignancies underwent 18FDG-PET scintigraphy followed by EBUS within the ensuing 3 weeks. One-two nodes were assessed in each patient, determined by 18FDG-PET findings and accessibility of the FDG-positive nodes. The mediastinal nodal status from each procedure was compared. EBUS resulted in mediastinal nodal status downgrading in 25 (40%) patients. No upgrading was noted. Downgrading most likely occurred when there several non-enlarged lymph nodes of similar 18FDG-avidity distributed randomly and bilaterally in the mediastinum, often with bilateral hilar uptake (17 of 25 patients). Further, only 2 of 19 patients exhibiting such a pattern of mediastinal tracer distribution were found to have lymph node metastases (10%), and both had metastatic disease elsewhere on the PET scan. 21 of 23 patients with positive EBUS findings demonstrated discrete 18FDG-avid lymph nodes ipsilaterally, with minimal-to-no 18FDG-avid nodes contralaterally. EBUS findings in 14 (23%) patients were inconclusive, despite multiple sampling. Enlarged, rounded lymph nodes with avid FDG uptake (SUV>4) were also more likely to harbor metastatic disease. Conversely, a Hounsfield unit of >55 was associated with benign disease. The pattern of mediastinal 18FDG uptake was highly predictive of metastatic disease, and may circumvent the need for EBUS evaluation. Prospective analysis of these parameters will be undertaken.

Optimiser le bilan d'extension locorégional

The initial assessment must meet four goals: assessing the clinical status, obtain a histological proof of diagnosis, set the stage cTNM, and if resectability, define whether the patient is operable. The locoregional staging modalities are based on national and international guidelines. Physical examination should be performed. Thorax CT-scan with contrast should be performed in all patients, except contraindication. CT can determine tumor size, bronchus, pleural, mediastinal and vascular invasion. The sensitivity and specificity of CT scan for identifying mediastinal lymph node metastasis is 61% and 79%, respectively. PET-CT is not indicated systematically but only for patients considered for curative intent treatment. The sensitivity and specificity of PET-CT for identifying mediastinal lymph node metastasis is 80 % and 80-90%, respectively. For patients with extensive mediastinal infiltration, CT assessment is sufficient. In patients with discrete mediastinal lymph node enlargement or PET uptake in mediastinal nodes or a centrally located tumour or a tumour > 3cm or N1 node, an invasive staging of the mediastinum is indicated. A needle technique (EBUS-TBNA or EUS-FNA or combined EBUS/EUS) is recommended over surgical staging. Stage IIIAN2 should be classified into potentially resectable N2, potentially resectable N2 but risk of incomplete resection and unresectable N2. The adherence to guidelines and organizational factors improve the management.

F-18-Fluorodeoxyglucose Positron Emission Tomography-Guided Sampling of Mediastinal Lymph Nodes in the Diagnosis of Cardiac Sarcoidosis

Histologic proof of granulomatous inflammation is prerequisite for the diagnosis of cardiac sarcoidosis (CS). Because of the limited sensitivity of endomyocardial biopsy (EMB), confirmation of sarcoidosis often has to be acquired from extracardiac biopsies. We set out to review our experience of F-18-fluorodeoxyglucose positron emission tomography (F-18-FDG PET) in guiding extracardiac tissue biopsies in suspected CS. We included in this work 68 consecutive patients with proved CS who had undergone cardiac F-18-FDG PET with (n = 57) or without whole-body imaging as part of initial diagnostic evaluation. Their hospital charts, imaging studies, and diagnostic biopsies were reviewed in retrospect. Whole-body PET images showed extracardiac foci of abnormally high F-18-FDG uptake in 39 of 57 patients, of whom 38 had involvement of mediastinal lymph nodes (MLN). Parallel F-18-FDG uptake was found in other lymph nodes (n = 10), lungs (n = 9), liver (n = 3), spleen (n = 2), and thyroid gland (n = 1). Adding the mediastinal findings at cardiac PET without whole-body imaging, abnormal F-18-FDG uptake in MLN was found in totally 43 of the 68 patients with CS (63%). Histology of systemic sarcoidosis was known at presentation of cardiac symptoms in 8 patients. Of the 60 patients with missing histology, 24 patients underwent mediastinoscopy for sampling of PET-positive MLN, most often (n = 20) after nondiagnostic EMB; microscopy revealed diagnostic noncaseating granulomatous inflammation in 24 of the 24 cases (sensitivity 100%). In the remaining 36 patients, sarcoidosis histology was confirmed by EMB (n = 30), by biopsy of lungs (n = 2) or peripheral lymph nodes (n = 2), or at autopsy (n = 1) or post-transplantation (n = 1). In conclusion, MLN accumulate F-18-FDG at PET in most patients with CS and provide a highly productive source for diagnostic biopsies either primarily or subsequent to nondiagnostic EMB.

Immunoglobulin G4-related Disease with Features of Mikulicz's Disease and Autoimmune Pancreatitis Which Firstly Presented as Asymptomatic Lymphadenopathy

Immunoglobulin G4-related Disease with Features of Mikulicz's Disease and Autoimmune Pancreatitis Which Firstly Presented as Asymptomatic Lymphadenopathy

Two patients with intestinal failure requiring home parenteral nutrition, a NOD2 mutation and tuberculous lymphadenitis

BackgroundMutations in the NOD2 gene are a significant risk factor to acquire intestinal failure requiring home parenteral nutrition. Tuberculous lymphadenitis is the main manifestation of extrapulmonary tuberculosis. Defects in the innate immunity, including NOD2 mutations, may increase the risk for acquiring infections caused by M. tuberculosis. An association of intestinal failure, mutations in the NOD2 gene and tuberculous lymphadenitis has not been described before.Case presentationWe report of two patients with intestinal failure secondary to mesenteric ischemia. Both patients presented with fever and weight loss while receiving long term home parenteral nutrition. Both of them were found to have mutations in the NOD2 gene. Catheter related infections were ruled out. FDG-PET-CT scans initially obtained in search for another infectious focus that would explain the symptoms unexpectedly showed high FDG uptake in mediastinal lymph nodes. Direct or indirect evidence proved or was highly suggestive for tuberculous lymphadenitis. Intravenous tuberculostatic therapy was started and led to a reversal of symptoms and to resolution of the lesions by FDG-PET-CT.ConclusionMutations in the NOD2 gene may put patients both at an increased risk for acquiring M. tuberculosis infections as well as at an increased risk of intestinal failure after extensive intestinal resection. Thus we suggest to specifically include reactivated and opportunistic infections in the differential diagnosis of suspected catheter related infection in patients with intestinal failure who carry mutations in their NOD2 gene.

Sarcoidosis lymphoma syndrome - the value of PET-CT in the diagnosis

We report a 52-year-old patient who developed B-cell non-Hodgkin’s lymphoma subsequent to sarcoidosis. Sarcoidosis was diagnosed 16 years ago and remained asymptomatic for 14 years after steroid treatment. She presented with new symptoms of arthralgia, photosensitivity, butterfly erythema, autoimmune antibodies (ANA, chromatin positivity) associated with progression of the known left upper lobe lesion on the chest X-ray suggesting primary autoimmune disease (systemic lupus erythematosus). As steroid treatment was not effective, we started bolus cyclophosphamide therapy after which progression was seen on the chest X-ray. Computed tomography (CT)-guided needle biopsy confirmed malignancy of indefinable origin. Despite of the well-known fluorodeoxyglucose (FDG) avidity in active sarcoidosis, a FDG-positron emission tomography (PET) scan was performed to stage the primary tumour. Intensive FDG uptake was detected in the affected lung segment, with moderate uptake in mediastinal lymph nodes. The patient underwent left upper lobectomy. The histology showed pulmonary mucosa-associated lymphoma (bronchus-associated lymphoid tissue (BALT) lymphoma) in the lung tissue, while only sarcoidosis was present in the mediastinal lymph nodes. Bone marrow biopsy was negative.The association between sarcoidosis and lymphoma is known as sarcoidosis lymphoma syndrome, which is a rare disease. PET-CT was helpful in the differentiation of sarcoidosis and malignancy in this patient. It is important to be aware of the risk of lymphoma in sarcoidosis and FDG-PET, used for adequate purpose, can help the diagnosis.

Isolated Mediastinal Lymph Node False Positivity of [18F]-Fluorodeoxyglucose–Positron Emission Tomography/Computed Tomography in Patients With Cervical Cancer

This study aimed to evaluate the degree of mediastinal involvement in patients with cervical cancer with isolated mediastinal [F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) positivity as verified by histopathologic examination. Two hundred twenty-eight patients with newly diagnosed cervical cancer and who underwent FDG-PET imaging were analyzed. Twenty-nine patients (17%) had disseminated disease detected with PET/computed tomography (CT). Only 10 patients (4%) had increased FDG uptake in mediastinal lymph nodes alone. Of the 10 patients with mediastinal disease, 2 refused surgical mediastinal lymph node biopsy and did not receive any treatment. Patients with suspected paratracheal or subcarinal lymph node metastasis detected on PET/CT underwent mediastinoscopy, and those with hilar metastasis had video-assisted mediastinal lymphadenectomy. Treatment was delivered according to final staging based on histopathologic confirmation of mediastinal lymph node involvement. The mean (SD) maximum standardized uptake values for primary cervical tumor and mediastinal lymph nodes were 19.7 (10.3) and 7.5 (1.6), respectively. Of 8 patients who underwent mediastinal lymph node confirmation, 6 (75%) were tumor free, demonstrating granulomatous changes, and were treated curatively. No patients had residual or recurrent disease at the primary site, and all but 1 were alive without disease. Two patients with confirmed mediastinal lymph node metastasis were treated palliatively and died between 9 and 11 months after diagnosis. Positron emission tomography/CT is an important tool for lymphatic staging and evaluation of distant metastases in cervical cancer. However, PET/CT should be interpreted cautiously for isolated mediastinal involvement; surgical evaluation is required for accurate staging and appropriate treatment decisions to achieve better outcomes.

Comparison between sarcoidosis and IgG4-related disease by whole-body 67Ga scintigraphy

The aim of this study was to compare uptake lesions in sarcoidosis and IgG4-related disease through gallium-67 ((67)Ga) scintigraphy to differentiate between the two diseases. Whole-body (67)Ga scintigraphy findings of 27 patients with sarcoidosis and 16 with IgG4-related disease were reviewed between 2005 and 2011 at our hospital. In the case of patients with sarcoidosis, significant accumulation of (67)Ga was observed in the lacrimal gland in the case of 26 patients (96%), in mediastinal lymph nodes (LNs) in 23 (85%), in pulmonary hilar LNs in 21 (78%), in the parotid gland in 10 (38%), in supraclavicular LNs in eight (30%), in muscles in seven (26%), in the lung in five (18%), in inguinal LNs in four (15%), in submandibular LNs in two (7%), and in the heart, spleen, kidney and para-aorta in one patient (4%). In patients with IgG4-related disease, abnormal uptake was detected in the pulmonary hilar LNs in 12 patients (75%), in the lacrimal gland in 10 (62%), in the pancreas in 10 (62%), in the parotid gland in six (37%), in the submandibular gland in six (37%), in the para-aorta in three (19%), in the lung in three (19%), in mediastinal LNs in two (12%), and in the kidney in the case of two patients (12%). Asymmetrical accumulation in the submandibular gland was observed in three of six patients (50%) with IgG4-related disease and in none of the two patients (0%) with sarcoidosis. Significant differences were observed in the uptake ratio of the lacrimal gland, the submandibular gland, supraclavicular LNs, mediastinal LNs, pancreas, and muscle between the two groups (P<0.05). (67)Ga scintigraphy was useful in differentiating between the two diseases. Uptake in mediastinal LNs, in supraclavicular LNs, and in the muscle was specific to sarcoidosis, whereas uptake in the pancreas and in the submandibular gland indicated IgG4-related disease.

Comparison of Integrated Positron Emission Tomography/Computed Tomography and Mediastinoscopy in Mediastinal Staging of Non-Small Cell Lung Cancer: Analysis of 212 Patients

Background : Mediastinal staging is crucial to determine the prognosis and treatment options for patients with non-small cell lung cancer (NSCLC). In this study, we compared the results of integrated positron emission tomography-computerised tomography (PET/CT) with those of mediastinoscopy in mediastinal staging of NSCLC patients. Methods : PET/CT and mediastinoscopy was performed on 250 consecutive patients diagnosed with NSCLC between September 2005 and March 2008. Thirty-eight patients were excluded from the study. Standard cervical mediastinoscopy was performed in all patients, and simultaneous extended cervical mediastinoscopy was performed in 52 patients with left sided lesions. Patients with negative mediastinoscopy underwent resection. The pathological results were correlated with PET/CT findings.Results : A total of 212 patients (199 male, 13 female; mean age: 58.3 years) were evaluated. In PET/CT analysis 60 true-positive, 45 false-positive, 103 true-negative and 4 false-negative patients were found. The rate of PET/CT positivity of mediastinal lymph nodes was 49.5%. The sensitivity, specificity, positive and negative predictive values and accuracy for PET/CT were 93.8%, 69.6%, 57.1%, 96.3% and 76.9% respectively. The incidence of N2 disease in NSCLC patients with negative mediastinal lymph node uptake on PET/CT was 3.7% (4 of 107). In univariate analysis, right upper lobe tumours were significantly (p < 0.05) more associated with occult N2 disease.Conclusions : In patients with positive mediastinal lymph node uptake on PET/CT invasive mediastinal staging appears necessary for exact staging. Mediastinoscopy can be omitted in NSCLC patients with negative mediastinal uptake on PET/CT in regions where the rate of PET/CT positivity of mediastinal lymph nodes is high.

Mediastinal lymph node uptake in patients with prostate carcinoma on F18-choline PET/CT

Fluorine-18-methyl-choline (F18-choline) PET/computed tomography (CT) is routinely performed in our hospital for patients with significantly increased or rapidly increasing prostate-specific antigen (PSA) levels to detect and localize recurrent prostate carcinoma. We observed uptake of this PET tracer in mediastinal lymph nodes in a significant number of patients. The aim of this study was to assess the frequency of this finding and to determine whether it is correlated with tumour and nontumour-related aspects. A total of 48 consecutive men (mean age: 65.6 years; range: 50-79 years, standard deviation: 7.1) with histopathologically proven prostate cancer were referred for F18-choline PET/CT imaging for restaging from March 2009 to October 2010. All patients had a suspicion of tumour recurrence because of an increased PSA or a rapidly increasing PSA. All studies were reviewed, and the results were correlated with general data such as age; smoking; chronic obstructive pulmonary disease; tumor, lymph nodes and distant metastases stage; Gleason Score and PSA level; with a maximum interval of 3 months between serum PSA and the PET/CT scan. In 27 patients (56.3%), F18-choline PET/CT showed positive lymph nodes in the mediastinum (mean standardized uptake values: 3.75; range: 1.7-13.8, standard deviation: 2.4). No histological biopsy was carried out in F18-choline-positive lymph nodes, but in none of the patients was mediastinal recurrence or pulmonary infection observed during a 6-month follow-up. Only one patient had histologically proven pulmonary metastasis. No significant relationship was observed between mediastinal F18-choline lymph node uptake and serum PSA level (P=0.785), initial T stage (P=0.555), N stage (P=0.548), M stage (P=0.426), smoking (P=0.537), chronic obstructive pulmonary disease (P=0.115) or the presence of tumour recurrence on F18-choline PET/CT. Mediastinal lymph node uptake of F18 choline is frequently observed, without any significant relationship with tumour characteristics. Therefore, interpretation of positive mediastinal lymph node uptake should be done carefully.

Role of FDG PET/CT and Chest CT in the Follow-up of Lung Lesions Treated with Radiofrequency Ablation

To compare fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) combined with computed tomography (PET/CT) and chest CT in the evaluation of the effectiveness of lung radiofrequency (RF) ablation. Institutional review board approved the study, and all patients gave written informed consent. Thirty-four patients (22 men and 12 women; mean age, 64 years) planned to undergo lung RF ablation were prospectively included and underwent FDG PET/CT and chest CT before (pre-RF ablation PET) and 24 hours, 1 month, and 3 months after RF ablation. Persistent equivocal findings up to 3 months were followed up. Pre-RF ablation PET led to changes in the treatment strategy in nine patients (26%) by depicting unexpected metastases. Two patients without FDG uptake in lesions to be treated were excluded. Overall, 28 patients (46 lesions: five primary cancer, 41 metastases) were treated and followed up. Within 3 months after RF ablation, incomplete treatment was diagnosed in four of 28 patients (14%, three at 1 month and one at 3 months). Findings of FDG PET/CT were true-positive in four, false-positive in one, and true-negative in 23 patients. Findings of chest CT were true-positive in one, false-positive in one, false-negative in three, and true-negative in 23 patients. Inflammatory FDG uptake in mediastinal lymph nodes and at the needle path puncture site used for RF ablation was observed in 15%, 21%, and 15% of patients and in 19%, 11%, and 15% of patients at 24 hours, 1 month, and 3 months, respectively. FDG PET/CT can be used for the evaluation of the effectiveness of lung RF ablation. Inflammatory FDG uptake in mediastinal lymph nodes or at the needle path site used for RF ablation may occur.

FDG PET findings in a case with acute pulmonary silicosis

A 21-year-old male having a history of 4 years of working at a denim factory as a sandblaster was diagnosed with pulmonary silicosis and he was also an active smoker. Productive cough, dyspnea on effort, night sweats, and weight loss in a short period of time were his complaints. Chronic occupational exposure to tiny particles of silicon dioxide can stimulate parenchymal inflammation, collagen synthesis and, ultimately pulmonary fibrosis called silicosis. A typical history of exposure and chest X-ray is usually enough for diagnosis. No effective treatment exists except supportive care. Although chest X-ray of the patient revealed bilateral disseminated micronodular densities, a peripherally diffuse prominent FDG [(F-18)-2-fluoro-2-deoxy-D-glucose] uptake in both lungs and faint FDG uptake in mediastinal lymph nodes demonstrating active inflammation regions were noted on PET (Positron Emission Tomography) scan. This case was presented to show the active disease discriminated by FDG PET from chronic changes detected by radiological studies. FDG PET can provide additional information to CT regarding the diagnosis of acute silicosis and the rare accelerated silicosis.

Detection of lymph node metastases with ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance imaging in oesophageal cancer: a feasibility study

Aim: In this feasibility study we investigated whether magnetic resonance imaging (MRI) with ultrasmall superparamagnetic iron oxide (USPIO) can be used to identify regional and distant lymph nodes, including mediastinal and celiac lymph node metastases in patients with oesophageal cancer.Patients and methods: Ten patients with a potentially curative resectable cancer of the oesophagus were eligible for this study. All patients included in the study had positive lymph nodes on conventional staging (including endoscopic ultrasound, computed tomography and fluorodeoxyglucose-positron emission tomography). Nine patients underwent MRI + USPIO before surgery. Results were restricted to those patients who had both MRI + USPIO and histological examination. Results were compared with conventional staging and histopathologic findings.Results: One patient was excluded due to expired study time. Five out of 9 patients underwent an exploration; in 1 patient prior to surgery MRI + USPIO diagnosed liver metastases and in 3 patients an oesophageal resection was performed. USPIO uptake in mediastinal lymph nodes was seen in 6 out of 9 patients; in 3 patients non-malignant nodes were not visible. In total, 9 lymph node stations (of 6 patients) were separately analysed; 7 lymph node stations were assessed as positive (N1) on MRI+USPIO compared with 9 by conventional staging. According to histology findings, there was one false-positive and one false-negative result in MRI + USPIO. Also, conventional staging modalities had one false-positive and one false-negative result. MRI + USPIO had surplus value in one patient. Not all lymph node stations could be compared due to unforeseen explorations. No adverse effects occurred after USPIO infusion.Conclusion: MRI+USPIO identified the majority of mediastinal and celiac (suspect) lymph nodes in 9 patients with oesophageal cancer. MRI+USPIO could have an additional value in loco-regional staging; however, more supplementary research is needed.

Use of integrated FDG-PET/CT in sarcoidosis

We studied five patients with mediastinal lymph node enlargement suggestive of malignant lymphoma, lung cancer, or sarcoidosis. Integrated [ 18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) was performed on all patients. Sarcoidosis can be a pitfall in PET/CT imaging, which may lead to false-positive results of malignancy. Increased FDG uptake in mediastinal lymph nodes is often comparable with malignant lymphoma or lymph node metastases. Histological confirmation of the lesions should be mandatory, except for patients in whom sarcoidosis can be accurately confirmed by other diagnostic methods.

Goitre ovarien malin : faux positif du TEP-scan lié à une sarcoïdose

Struma ovarii is an ovarian teratoma mainly composed of thyroid tissue, which can become malignant with possible peritoneal dissemination or even distant metastases. Therapeutic management follows protocols used for thyroid cancer. We report the first use of (18)F-fluorodeoxyglucose positron emission tomography (PET) in the follow-up of malignant struma ovarii with persistently elevated serum thyroglobulin level and negative diagnostic iodine 131 whole body scan after thyroidectomy and four courses of 131 iodine. Hilar and mediastinal lymph node uptake was detected but histological verification concluded that there was a false-positive localization corresponding to sarcoidosis lesions without malignant aspect.