Fluorodeoxyglucose PET-CT Research Articles

Characterisations and Scan Findings of Non-Small Cell Lung Cancer Seen on Staging FDG PET-CT: Contemporary Review and Institutional Experience

Objective: Fluorodeoxyglucose (FDG) PET-CT scan is extensively being applied in oncology including lung cancer staging and treatment response assessment by depicting glucose consumption of malignant cells. Non- small cell lung cancer (NSCLC) cases such as adenocarcinoma and squamous cell carcinoma (SCC) are more prevalent. We aimed to determine the FDG uptake avidity based on semiquantitative maximum Standardise Uptake Value (SUVmax) observed on staging PET-CT of newly diagnosed NSCLC and associated contributing factors. Methods: Retrospective review of 125 cases of biopsy proven lung cancer referred for FDG PET-CT in our institution over the past 2 years. Staging PET-CT scans (n=54) were included for analysis. Clinical parameters and PET-CT findings (SUVmax of primary lesion, presence of nodal and metastatic disease) were investigated. SUVmax of primary lesion for SCC and adenocarcinoma was compared. Association between SUVmax of primary lesion and extrapulmonary FDG- avid lesions presence was also determined. Results: Males were predominant (60%). Average age was 62.5 years. Majority were adenocarcinoma (65%) followed by SCC (22%) and others (13%). Mean tumour size was 5.1 cm. Lung SCC demonstrated intensely increased FDG uptake that was significantly higher compared to adenocarcinoma (average SUVmax 24.4 vs SUVmax 15.6, p<0.05). FDG-avid ipsilateral hilar nodal involvement seen in 63%, mediastinal nodes in 70% while distant metastatic disease in 33%. Patients having primary lesion with SUVmax 20.0 and above were significantly associated with larger tumour size and FDG-avid ipsilateral hilar nodal uptake (p<0.05). Conclusion: Lung SCC was intensely FDG-avid and had higher SUVmax compared to adenocarcinoma. Primary lesions with SUVmax 20.0 and above were associated with larger tumour size and presence of hypermetabolic ipsilateral hilar nodal spread. Information obtained from this review will provide valuable insight into PET-CT scan characteristics of newly diagnosed NSCLC cases in our institution that may influence not only scan reporting formulation but also patient management.International Journal of Human and Health Sciences Supplementary Issue 01: 2024 Page: S46

[18F]-fluorodeoxyglucose PET-CT in systemic amyloidosis with cardiac involvement

[18F]-fluorodeoxyglucose PET-CT in systemic amyloidosis with cardiac involvement

Head and Neck Cancer Segmentation in FDG PET Images: Performance Comparison of Convolutional Neural Networks and Vision Transformers.

Convolutional neural networks (CNNs) have a proven track record in medical image segmentation. Recently, Vision Transformers were introduced and are gaining popularity for many computer vision applications, including object detection, classification, and segmentation. Machine learning algorithms such as CNNs or Transformers are subject to an inductive bias, which can have a significant impact on the performance of machine learning models. This is especially relevant for medical image segmentation applications where limited training data are available, and a model's inductive bias should help it to generalize well. In this work, we quantitatively assess the performance of two CNN-based networks (U-Net and U-Net-CBAM) and three popular Transformer-based segmentation network architectures (UNETR, TransBTS, and VT-UNet) in the context of HNC lesion segmentation in volumetric [F-18] fluorodeoxyglucose (FDG) PET scans. For performance assessment, 272 FDG PET-CT scans of a clinical trial (ACRIN 6685) were utilized, which includes a total of 650 lesions (primary: 272 and secondary: 378). The image data used are highly diverse and representative for clinical use. For performance analysis, several error metrics were utilized. The achieved Dice coefficient ranged from 0.833 to 0.809 with the best performance being achieved by CNN-based approaches. U-Net-CBAM, which utilizes spatial and channel attention, showed several advantages for smaller lesions compared to the standard U-Net. Furthermore, our results provide some insight regarding the image features relevant for this specific segmentation application. In addition, results highlight the need to utilize primary as well as secondary lesions to derive clinically relevant segmentation performance estimates avoiding biases.

False positive PET-CT imaging after application of fibrin-based sponge at the site of previous hepatic resection for colo-rectal metastasis: A short series

Surgical resection is the treatment of choice with curative intent for colorectal liver metastasis. Preoperative accurate radiological staging is key for optimal treatment. Fluorine-18 fluorodeoxyglucose PET-CT (PETCT) is effective for this purpose. We present 4 cases of patients with history of hepatectomy for colorectal liver metastasis. In all patients, during the procedure, we used fibrin-based sponge to achieve optimal haemostasis of the parenchymal transection surface. During the oncologic follow-up, a suspicion of disease recurrence justified a staging PET-CT that revealed pathologic metabolic activity on sites of previous liver resection, highly suspicious of tumour recurrence. The delay between hepatectomy and PET-CT for recurrence ranged from 5 to 12 months. In all cases, a new surgical exploration was performed after neoadjuvant chemotherapy, and PET-CT positive sites of previous liver resection were removed. Definitive histological diagnosis showed inflammatory granuloma or fibrous tissue.

1634-P: Brown Adipose Tissue and Muscle Responses to Tolerable Cold in Black and White Young Lean Men

There has been a renewed interest in brown adipose tissue (BAT) as a therapeutic target for diabetes and obesity treatments due to its ability to consume glucose and expend energy in response to cold temperatures and Beta-adrenergic stimulation. However, comparisons of BAT in different races are limited. To address this knowledge gap, we directly compared healthy, young, lean Black and White men in a controlled inpatient study using a whole-room indirect calorimeter. 12 Black and 12 White men completed a 6-13-day protocol with randomized calorimeter temperatures between 18-31°C for 5 hours. Resting metabolic rate (RMR) was measured under reclined, fasted conditions with standard clothing. Body composition was measured by dual x-ray absorptiometry and BAT and muscle glucose uptake activity was quantified using 18-F Fluorodeoxyglucose (18-F FDG) PET-CT following the last chamber study where each individual's coldest tolerable temperature (Tct) was used. Basal metabolic rate (BMR) was defined as minimum RMR and the cold-induced thermogenesis (CIT) was calculated as the percentage increase of RMR above BMR in the cold. The groups were similar in age (23.8±4.7 yrs) and BMI (23.1±1.5 kg/m2) and their Tct (21.0±1.4°C; p=0.54) and CIT (12.1±8.1 kcal/h; p=0.8) were not different. While White males had significantly higher BAT volume (334 ± 188mL vs 242 ± 89mL; p=0.045), BAT volume was comparable between the groups after normalizing to body volume. BAT activity was similar between the groups. Among all muscle activity measured, the intercostal muscles in the Black males had significantly higher activity (p=0.002) and activity was present in all 12 Black participants but only 4 of 12 White males. Individual BAT or muscle activity did not correlate with each other nor with Tct or CIT. Our data suggest that the cold-induced BAT activity was comparable in Black and White young, lean men. The surprising difference in intercostal muscle activity warrants further investigation. Disclosure R.J.Thomas: None. R.Brychta: None. A.B.Courville: None. S.Mcgehee: None. A.M.Cypess: None. K.Y.Chen: None.

An interesting case of Posterior Layering in the Urinary bladder on Fluorine- 18 Fluorodeoxyglucose (F18-FDG) PET-CT study

Contrast PET/CT may show layering within the UB, and several examples of have been reported in the literature. But without using contrast this is rare. Our case demonstrates the interesting posterior layering of F18-FDG in urinary bladder in a 78 years old male without the use of contrast.
 Pulse Volume 12-14 2020-2022 p.32-33

Independent association of metabolic tumor response on FDG-PET with pulmonary toxicity following risk-adaptive chemoradiation for unresectable non-small cell lung cancer: Inherent radiosensitivity or immune response?

BackgroundIn the context of a phase II trial of risk-adaptive chemoradiation, we evaluated whether tumor metabolic response could serve as a correlate of treatment sensitivity and toxicity. MethodsForty-five patients with AJCCv7 stage IIB-IIIB NSCLC enrolled on the FLARE-RT phase II trial (NCT02773238). [18F]fluorodeoxyglucose (FDG) PET-CT images were acquired prior to treatment and after 24 Gy during week 3. Patients with unfavorable on-treatment tumor response received concomitant boosts to 74 Gy total over 30 fractions rather than standard 60 Gy. Metabolic tumor volume and mean standardized uptake value (SUVmean) were calculated semi-automatically. Risk factors of pulmonary toxicity included concurrent chemotherapy regimen, adjuvant anti-PDL1 immunotherapy, and lung dosimetry. Incidence of CTCAE v4 grade 2+ pneumonitis was analyzed using the Fine-Gray method with competing risks of metastasis or death. Peripheral germline DNA microarray sequencing measured predefined candidate genes from distinct pathways: 96 DNA repair, 53 immunology, 38 oncology, 27 lung biology. ResultsTwenty-four patients received proton therapy, 23 received ICI, 26 received carboplatin-paclitaxel, and 17 pneumonitis events were observed. Pneumonitis risk was significantly higher for patients with COPD (HR 3.78 [1.48, 9.60], p = 0.005), those treated with immunotherapy (HR 2.82 [1.03, 7.71], p = 0.043) but not with carboplatin-paclitaxel (HR 1.98 [0.71, 5.54], p = 0.19). Pneumonitis rates were similar among selected patients receiving 74 Gy radiation vs 60 Gy (p = 0.33), proton therapy vs photon (p = 0.60), or with higher lung dosimetric V20 (p = 0.30). Patients in the upper quartile decrease in SUVmean (>39.7%) were at greater risk for pneumonitis (HR 4.00 [1.54, 10.44], p = 0.005) and remained significant in multivariable analysis (HR 3.34 [1.23, 9.10], p = 0.018). Germline DNA gene alterations in immunology pathways were most frequently associated with pneumonitis. ConclusionTumor metabolic response as measured by mean SUV is associated with increased pneumonitis risk in a clinical trial cohort of NSCLC patients independent of treatment factors. This may be partially attributed to patient-specific differences in immunogenicity.

PO-01-087 A RARE CASE OF BI-ATRIAL FDG-UPTAKE: PRESENTING AS NEW ONSET ATRIAL FIBRILLATION

Isolated atrial myocarditis is rare, with presenting symptoms that are non-specific. Prior reports have suggested association with atrial arrythmias and increased risk of stroke due to atrial dysfunction. Fluorodeoxyglucose (FDG)-positron emission tomography (PET) CT scan is considered as a goal standard test for the diagnosis of myocarditis. To present a case highlighting that isolated atrial myocarditis had higher incidence atrial arrythmias and oral anticoagulation should be considered in such cases. N/A A 55yo male with no prior medical history presented with non-specific symptoms of fatigue, shortness of breath and frequent palpitations. He underwent 2D echocardiogram showed LVEF of 50-55% with mild bi-atrial dilatation with no regional wall motion abnormalities and was diagnosed with incidental atrial fibrillation during the procedure. He was referred to cardiac electrophysiology for further work up. During his initial EP clinic visit, 12 lead ECG demonstrated normal sinus rhythm with premature atrial contractions and premature ventricular contractions. Due to symptomatic, dual chamber arrythmias, cardiac MRI (CMR) and FDG-PET CT was ordered to rule out myocarditis. The CMR was negative for any LGE however, high-fat dietary preparation FDG-PET CT scan revealed uptake on bi-atrial walls (figure) and interatrial septum with SUV max of 3.1. There was no LV myocardial FDG uptake noted. Patient was diagnosed with isolated atrial myocarditis and was started on dronedarone, OAC (CHADS2VASc =0) for stroke prophylaxis and immunosuppressive therapy (methotrexate and low dose prednisone). Invasive atrial myocardial biopsy was not considered due good response to therapy. Isolated atrial myocarditis is an uncommon presentation of acute myocarditis and is associated with atrial arrythmias. FDG PET-CT or CMR imaging may be useful to aid diagnosis. Long-term response to immunosuppressive therapy may need further investigations. OAC should be considered for stroke prophylaxis, despite low CHADS2VASc due to unknown long-term implications of atrial dysfunction.

Role of 18F-FDG PET-CT Imaging in a Patient with Renal Ewing’s Sarcoma: A Rare Case Report

Ewing's sarcoma (ES) is a bone-related tumor that typically affects young children and adolescents. Primary renal Ewing sarcoma (RES) is extremely rare. Sources of Ewing sarcoma in the kidney include invagination or migration of neural crest cells to the kidney. Here, a case of a young adult male with renal Ewing sarcoma is presented. A 28-year-old male presented with nausea, hematuria, and left flank pain for seven days with an unremarkable previous medical history. An ultrasound and CT scan revealed a massive lobulated mass in the upper and midsection of the left kidney. A radical nephrectomy was done. Histopathology and immunohistochemistry revealed Ewing’s sarcoma/primitive neuroectodermal tumor. The chest X-ray and chest CT scan were negative for metastasis. Initial staging was T2bNxM0. Before starting further treatment, the patient was advised to undergo a fluorine-18 FDG (fluorodeoxyglucose) positron emission tomography (F-18 FDG PET-CT) scan for the detection of occult metastases. A F-18 FDG PET-CT scan revealed peritoneal seeding, skeletal and abdominal lymph node metastases. A multimodality workup is essential for proper management of Ewing sarcoma of the kidney due to its rarity and unusual location. F-18 FDG PET-CT plays a critical role in the detection of occult metastases, staging, restaging, and treatment planning in patients with RES. Bangladesh J. Nuclear Med. 26(1): 54-57, 2023

Variable Relative Biological Effectiveness of Proton Therapy Increases PET-Visible Mucosal Injury in Head and Neck Cancer Patients

Despite dosimetric advantages of proton therapy in head and neck cancers, there is concern for increased end of range relative biologic effectiveness (RBE) and subsequent dose enhancement and mucosal toxicity with proton therapy. Herein, we evaluated differences in mucosal PET avidity on post-treatment scans as a surrogate for mucosal injury between proton and photon therapy patients. We further assessed the relationship between PET changes and RBE. The cohort comprised 9 proton and 10 photon patients who received ≥50 Gy adjuvant radiotherapy to oropharyngeal mucosa who remained loco-regional disease free ≥6 months post-treatment. All patients underwent follow-up fluorodeoxyglucose (FDG) PET-CT scans 3 months post-radiotherapy. PET-CTs were fused to planning CTs using deformable registration. High- and low-uptake regions were auto-contoured using a ≥150% mean liver standard uptake value (SUV) threshold and intersected with mucosal targets with/without a 5mm margin. SUV maximum (SUVMAX) values, linear energy transfer (LET) statistics, and RBE statistics based on McNamara, Jones, and linear LET models were extracted and compared. The mucosal target SUVMAX values on post-treatment PET-CTs for proton patients averaged 6.78 compared to 4.83 for photon patients (p=0.0267). Near maximum (LETd1%) LET for mucosal targets with a 5mm margin averaged 5.232 keV/µm. RBE in high-uptake regions exceeded that of low-uptake regions (p=0.0039), with mean biologic dose exceeding clinical dose by 11.05%, 18.67%, and 15.65%, respectively, using different RBE models. Post-radiotherapy PET avidity was more commonly observed in proton patients. Within proton patient mucosal targets, the location of increased PET avidity corresponded to areas with higher RBE. This is the first report of differential PET findings based on RBE. These results suggest that elevated RBE was associated with PET avidity and mucosal injury.

Periosteal Ewing Sarcoma: Imaging Features and Clinical Outcomes in 7 Patients.

The aim of this study was to describe imaging features, treatment, and prognosis of patients with periosteal Ewing sarcoma (PES). Seven patients with PES treated between 2001 and 2020 were studied retrospectively for presenting symptoms, imaging features, treatment, and prognosis. Among the 7 patients (mean age, 27.3 years) with local pain and/or mass of less than 6 months duration, 4 were males and 3 females (1.3:1). These surface tumors involved 3 long bones and 4 pelvic bones. Radiographs showed cortical erosions with 2 and CT with 4 long bone tumors. All 7 surface tumors showed normal marrow on MRI, and 4 tumors demonstrated normal marrow activity on 18FFDG fluorodeoxyglucose PET-CT. The only exception was a PES involving iliac bone with thin cortex and marrow extension, which demonstrated hypermetabolic marrow activity. All patients were treated initially with chemotherapy and optional radiation treatment with complete tumor resolution of a tibial PES in 1 patient. The remaining 2 patients with long bone PES had tumor resection and limb-salvage surgery and the 4 patients with pelvic bone PES had hemipelvectomy after chemotherapy/radiation treatment. Five patients were disease-free with long-term survival. A patient with a long bone PES and solitary lung metastasis at onset had tumor resection and metastasectomy with complete recovery without tumor recurrence. The 2 patients with pubic bone PES had complete recovery without tumor recurrence; however, the remaining 2 patients with iliac bone PES developed distant metastases and died within 2 years of diagnosis. Periosteal Ewing sarcoma arises in periosteum of bone and spares medullary cavity. As compared with its intramedullary counterpart, the tumor has better prognosis with long-term survival. Rarely, the surface tumor arising at a bone with thin cortex, such as iliac bone or scapula, may have medullary involvement. We have described our experience in diagnosis and clinical management in 7 patients of this rare surface variant of the more common intramedullary Ewing sarcoma.

Defining the clinical utility of PET or PET-CT in idiopathic inflammatory myopathies: A systematic literature review

ObjectivesPositron emission tomography (PET), often combined with computed tomography (CT), is a well-established tool for diagnosing malignancy and inflammatory disease. The idiopathic inflammatory myopathies (IIM) are chronic, multi-system diseases characterised by skeletal muscle inflammation, the potential for extramuscular manifestations such as interstitial lung disease (ILD) and an increased risk of malignancy. We performed a systematic literature review to evaluate the utility of PET or PET-CT in evaluation of IIM. MethodsA search of Medline and EMBASE from 1990 to 2022 using keywords related to IIM and PET was performed. English language studies of adults with IIM who had PET or PET-CT were included. ResultsOur search identified 1173 potentially relevant abstracts, 19 of which were included. The majority of studies used [18F] fluorodeoxyglucose (FDG) PET or PET-CT scans, while the remainder used [18F] florbetapir and [11C] Pittsburgh compound B ([11C] PIB). The sensitivity and specificity of 18F-FDG-PET or 18F-FDG-PET-CT for diagnosing malignancy compared with standard detection methods was 66.7–94% and 80–97.8%, respectively. The sensitivity of 18F-FDG PET-CT for ILD was 93–100% when high-resolution CT was used as the reference standard. 18F-PET and 18F-FDG-PET-CT appear to accurately detect muscle inflammation, although correlations with clinical measures of IIM disease activity were variable. [18F] florbetapir PET-CT and [11C] PIB PET were able to differentiate sporadic inclusion body myositis (IBM) from non-IBM IIM. ConclusionPET-CT holds promise as a single tool that can simultaneously evaluate multiple aspects of IIM. These include screening for associated malignancy, achieving an early diagnosis of ILD and evaluating muscle inflammation.

64Cu-SAR-Bombesin PET-CT Imaging in the Staging of Estrogen/Progesterone Receptor Positive, HER2 Negative Metastatic Breast Cancer Patients: Safety, Dosimetry and Feasibility in a Phase I Trial.

Breast cancers are most frequently oestrogen receptor (ER) and progesterone receptor (PR) positive and [18F]Fluorodeoxyglucose PET-CT (FDG) has lower sensitivity for these subtypes. The gastrin-releasing peptide receptor (GRPR) is overexpressed in ER+/PR+ breast cancers. This study assessed the safety and potential of [64Cu]Cu-Sarcophagine (SAR)-Bombesin PET/CT (BBN) in re-staging metastatic ER+/PR+/human epidermal growth-factor-2-negative (HER2-) breast cancer. Seven patients with metastatic ER+/PR+/HER2- breast cancer undergoing staging underwent [64Cu]Cu-SAR-BBN PET-CT. Bloods, vital signs and electrocardiogram, blood tracer-clearance and dosimetry were undertaken. GRPR status was assessed in available metastatic biopsy samples. Staging with conventional imaging ([18F]FDG, bone scan and diagnostic CT) was within 3 weeks of [64Cu]Cu-SAR-BBN PET/CT. PET scans were assessed visually and quantitatively. Seven patients underwent imaging. One of the seven had de-novo metastatic breast cancer and six of the seven recurrent metastatic disease. Two of the seven had lobular subtype. No adverse events were reported. All seven patients were positive on conventional imaging (six of seven on FDG). [64Cu]Cu-SAR-BBN imaging was positive in five of the seven. Both [64Cu]Cu-SAR-BBN-negative patients had disease identified on [18F]FDG. One patient was [64Cu]Cu-SAR-BBN positive/[18F]FDG negative. Four of seven patients were [64Cu]Cu-SAR-BBN positive/[18F]FDG positive. In these four, mean SUVmax was higher for [64Cu]Cu-SAR-BBN than [18F]FDG (SUVmax 15 vs. 12). In the classical lobular subtype (two of seven), [64Cu]Cu-SAR-BBN was more avid compared to [18F]FDG (SUVmax 20 vs. 11, and 20 vs. <3). Dosimetry calculations estimated whole-body effective dose for 200 MBq of [64Cu]Cu-SAR-BBN to be 1.9 mSv. [64Cu]Cu-SAR-BBN PET/CT appears safe and may have diagnostic value in metastatic ER+/PR+/HER2- breast cancer, particularly the lobular subtype. Further evaluation is warranted.

PET-CT in Clinical Adult Oncology: III. Gastrointestinal Malignancies.

Simple SummaryPositron emission tomography (PET), typically combined with computed tomography (CT), has become a critical advanced imaging technique in oncology. With PET-CT, a radioactive molecule (radiotracer) is injected in the bloodstream and localizes to sites of tumor because of specific cellular features of the tumor that accumulate the targeting radiotracer. The CT scan, performed at the same time, provides information to facilitate the characterization of radioactivity from deep or dense structures, and to provide detailed anatomic information. PET-CT has a variety of applications in oncology, including staging, therapeutic response assessment, restaging and surveillance. This series of six review articles provides an overview of the value, applications, and imaging interpretive strategies of PET-CT in the more common adult malignancies. The third report in this series provides a review of PET-CT imaging in gastrointestinal malignancies.PET-CT is an advanced imaging modality with many oncologic applications, including staging, assessment of response to therapy, restaging and longitudinal surveillance for recurrence. The goal of this series of six review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for specific oncologic indications, and the potential pitfalls and nuances that characterize these applications. In the third of these review articles, key tumor-specific clinical information and representative PET-CT images are provided to outline the role that PET-CT plays in the management of patients with gastrointestinal malignancies. The focus is on the use of 18F fluorodeoxyglucose (FDG), rather than on research radiopharmaceuticals under development. Many different types of gastrointestinal tumors exist, both pediatric and adult. A discussion of the role of FDG PET-CT for all of these is beyond the scope of this review. Rather, this article focuses on the most common adult gastrointestinal malignancies that may be encountered in clinical practice. The information provided here will provide information outlining the appropriate role of PET-CT in the clinical management of patients with gastrointestinal malignancies for healthcare professionals caring for adult cancer patients. It also addresses the nuances and provides interpretive guidance related to PET-CT for imaging providers, including radiologists, nuclear medicine physicians and their trainees.

Unknown Case: Unilateral Fluorodeoxyglucose Avid Axillary Lymphadenopathy in a Woman With History of Mastectomy and Implant Reconstruction.

A 67-year-old female presented with a history of right breast invasive ductal carcinoma and right axillary metastasis five years ago, status post bilateral mastectomies and right axillary lymph node dissection. Three years ago, she underwent implant reconstruction. She was diagnosed with metastasis to mediastinal lymph nodes one year ago after abnormal PET-CT and bronchoscopy. Fluorodeoxyglucose (FDG) PET-CT was performed for surveillance as she is currently on endocrine therapy. Fluorodeoxyglucose PET-CT demonstrated interval increase in size and hypermetabolic activity of a left axillary lymph node when compared to the prior year (Figure 1). Subsequent targeted left axillary US was performed for biopsy of this lymph node (Figure 2). On the biopsy images, the lymph node demonstrates a well-defined anterior margin with hyperechogenicity and echogenic noise. The differential diagnosis for unilateral lymphadenopathy includes benign and malignant etiologies (1,2). Benign etiologies include reactive...

Long-Term Performance of Untreated Fresh Autologous Pericardium as a Valve Substitute in Pulmonary Position

Background:Pulmonary regurgitation is imminent after transannular patch (TAP). We analyze the long-term performance of untreated autologous pericardium (UAP) as valve substitute at pulmonary position in patients requiring TAP.Material and Methods:This cross-sectional study include patients operated between 2007 and 2012 (n = 92). A sample of 19 patients was selected for this study which had a follow-up of more than 3 years. This includes patients with no TAP (n = 4) and with TAP and valve substitute, a monocusp (n = 11) or a tricuspid valve (n = 4) at neopulmonary annulus. Patients underwent echocardiography for assessment of right ventricle function and 18 fluoro-deoxyglucose PET CT scan for measurements of valve substitute at neopulmonary annulus. The target to blood ratio (TBR) of uptake of glucose by monocusp was measured at the cooptation edge of the neopulmonary valve.Results:The median age of the patients is 14 (9 – 37). RV function is preserved (TAPSE 18.9 (10.6 – 22.8)) at a mean follow-up of 4 years (3-9). The measurements of monocusp shows a shrinkage in height of the cusp by 35.5% (70% – 1.0%) and length by 7% (-44% - +104%). There was less shrinkage observed in patients below 15 years of age. The TBR of monocusp was 0.945 (0.17 – 3.35) with a strong correlation between the TBR values of aortic valve leaflet and monocusp leaflet of same patient.Conclusion:The UAP is functional and successful as a valve substitute at neo pulmonary annulus at long-term follow-up. It has resisted calcification and has shown uptake of glucose in physiological limits.

Imaging Lymphoma With F-18 Fluorodeoxyglucose PET-CT: What Should Be Known About Normal Variants, Pitfalls, and Artifacts?

18F fluorodeoxyglucose ([F-18] FDG) PET-CT has gained popularity in the management of many types of malignancies. Today, imaging patients with lymphoma using of [F-18] FDG PET-CT not only is considered as a state-of-the-art tool but also has taken a central place for therapeutic decisions. In fact, accurate staging at diagnosis is imperative to prevent under treatment of individuals with advanced disease. In Hodgkin's lymphoma, in particular, the current role of interim [F-18] FDG PET imaging goes beyond speculations in the adaptation of different therapeutic strategies. Therefore, the use of such a critical imaging modality should go hand in hand with sound interpretation that provides accurate results. As the number patients referred for PET-CT continues to increase, imaging specialists should remain aware of the inherent limitations linked to the integrated imaging system that may introduce potential pitfalls related to the machine or the administered [F-18] FDG. Knowledge of the normal physiologic biodistribution of [F-18] FDG, its physiologic variants, and of all the potential pitfalls and artifacts is paramount to avoid misinterpretation. Recognition of the limitations of [F-18] FDG PET-CT will increase the confidence of practicing clinicians on the modality and impact positively on the management of patients. In this article, we will review the normal physiological variants, technical artifacts, and diagnostic pitfalls in lymphoma. Highlighting the limitations of [F-18] FDG PET-CT imaging should warn interpreting specialists to find measures that mitigate them and improve reporting results.

18F-FDG PET-CTin rheumatoid arthritis patients tapering TNFi: reliability, validity and predictive value.

To investigate the reliability and validity of fluorine-18 fluorodeoxyglucose (18F-FDG) PET-CT scanning (FDG-PET) in RA patients with low disease activity tapering TNF inhibitors (TNFis) and its predictive value for successful tapering or discontinuation. Patients in the tapering arm of the Dose REduction Strategies of Subcutaneous TNFi study, a randomized controlled trial of TNFi tapering in RA, underwent FDG-PET before tapering (baseline) and after maximal tapering. A total of 48 joints per scan were scored both visually [FDG-avid joint (FAJ), yes/no] and quantitatively [maximal and mean standardized uptake values (SUVmax and SUVmean)]. Interobserver agreement was calculated in 10 patients at baseline. Quantitative and visual FDG-PET scores were investigated for (multilevel) association with clinical parameters both on a joint and patient level and for the predictive value at baseline and the change between baseline and maximal tapering (Δ) for successful tapering and discontinuation at 18 months. A total of 79 patients underwent FDG-PET. For performance of identification of FAJs on PET, Cohen's κ was 0.49 (range 0.35-0.63). For SUVmax and SUVmean, intraclass correlation coefficients were 0.80 (range 0.77-0.83) and 0.96 (0.9-1.0), respectively. On a joint level, swelling was significantly associated with SUVmax and SUVmean [B coefficients 1.0 (95% CI 0.73, 1.35) and 0.2 (0.08, 0.32), respectively]. On a patient level, only correlation with acute phase reactants was found. FDG-PET scores were not predictive of successful tapering or discontinuation. Quantitative FDG-PET arthritis scoring in RA patients with low disease activity is reliable and has some construct validity. However, no predictive values were found for FDG-PET parameters for successful tapering and/or discontinuation of TNFi.

OAB-060: Prospective comparison of contemporary whole body MRI and FDG PET/CT for disease detection and correlation with markers of disease burden in myeloma: results of the iTIMM trial

<h3>Background</h3> Sensitive detection of bone marrow disease and stratified patient management according to clinical risk can confer survival advantages in multiple myeloma (MM). Recent international guidelines include whole body MRI (WB MRI) and Fluorodeoxyglucose (FDG) PET/CT for bone marrow disease imaging in patients with a suspected diagnosis of MM. However, prospective studies comparing detection of MM by contemporary WB MRI as per MY-RADS consensus against FDG PET/CT are few. We report here on protocol-defined endpoints of the iTIMM (NCT02403102) study, which compared WB MRI and PET/CT, their relationship with serum and bone marrow estimates of disease burden, as well as molecular tumor characteristics. <h3>Methods</h3> The iTIMM study enrolled patients with newly diagnosed MM or at first relapse, planned to receive autologous stem cell transplantation. Matched baseline diffusion weighted and Dixon WB MRI and FDG PET/CT were performed and baseline clinical data including tumor genetics collected. Scans were double reported for presence of focal and diffuse disease by expert MRI and PET/CT radiologists, blinded to each other's assessment. Paired methods were used to compare burden and patterns of disease on WB MRI compared to FDG PET/CT at baseline. Exploratory endpoints include comparison of baseline WB MRI and PET/CT and their correlation with laboratory parameters, for which data is complete and reported here. <h3>Results</h3> Sixty patients (35 male; mean age 60 years) were enrolled between May 2015 and March 2018 and underwent paired baseline WB MRI as per MY-RADS and FDG PET/CT. At least one focal lesion was detected in 50/60 patients (83.3%) by WB MRI and in 36/60 patients (60%) by PET/CT. WB MRI was more sensitive (P<0.05, including Holm's correction for multiplicity) for long bones, lumbar spine and pelvis. Four patients in our study showed two or more focal lesions ≥5 mm only on WB MRI but not FDG PET/CT. All lesions detected by WB MRI but not PET/CT were resolving in follow-up scans after treatment, excluding false positives. In 49/60 (81.7%) patients, WB MRI detected diffuse disease, compared to 10/60 (16.7%) by FDG PET-CT; WB MRI was more sensitive across all anatomical areas (P<0.05 (Holm's)). All patients without focal disease presented diffuse disease on WB MRI (n=10). Bone marrow plasma cell infiltration and serum paraprotein levels were significantly higher for patients with diffuse disease on WB MRI, but not PET/CT. All genetically high-risk tumors, defined by t(4;14), t(14;16), del(1p), gain(1q) or del(17p), showed diffuse infiltration on WB MRI. <h3>Conclusions</h3> Contemporary WB MRI is more sensitive regarding detection of focal and diffuse disease compared with FDG PET/CT; together with its capability to assess response proposing it as a standard for tumor imaging in MM. In addition, measurability of diffuse disease and its association with higher disease burden and high-risk molecular profiles supports WB MRI radiomic biomarker development.

The usefulness of Fluorine-18 fluorodeoxyglucose PET-CT in detecting extranodal sites in the initial staging of non-Hodgkin and Hodgkin lymphoma (+ Running poster)

Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL) represent a spectrum of malignant neoplasms arising from the lymphoid system with an incidence of around 8% of all malignancies. Although they are generally known as tumors of lymph nodes, 25% to 40% of HD/NHL tumors, especially NHL, arise at extranodal sites along the gastrointestinal tract, lung, bone, soft tissues, liver, breast, thyroid, and genitourinary tract. the purpose of this study is to identify the extranodal sites in the initial staging of Hodgkin and non-Hodgkin lymphomas by FDG PET/CT. Seventy-six patients with NHL and 30 patients with HD in period 2017–2020 were retrospectively studied. Patients were selected with the following criteria: have biopsy proven histopathological HD or NHL, and extranodal sites on initial FDG PET/CT. The spleen is considered extranodal region in NHL and nodal organ in HD. Seventy-six patients with NHL (51 males, 25 females), extranodal sites correctly identified by 18F-FDG PET/CT: bone ( n = 33), soft tissues ( n = 24), lung ( n = 22), spleen ( n = 15), stomach ( n = 10), adrenal gland ( n = 8), liver ( n = 8), pleura ( n = 7), peritoneum ( n = 7), pericardium ( n = 5), kidney ( n = 4), mammary gland ( n = 3), thyroid ( n = 3), brain ( n = 2), prostate gland ( n = 2), pancreas ( n = 1), testis ( n = 1). Thirty patients with HD (22 males, 8 females), extranodal sites correctly identified by 18F-FDG PET/CT: Bone ( n = 22), lung ( n = 8), liver ( n = 6), pleura ( n = 2), soft tissues ( n = 1), brain ( n = 1). 18F-FDG PET/CT has become the technique of choice for staging and follow-up in patients with extranodal involvement in HD and in most cases of non-NHL. The potential presence of extranodal involvement should be considered when interpreting FDG PET/CT studies. Awareness of the increasing frequency of the appearance of unusual single extranodal sites of involvement in NHL and HD is important, since their presence may change treatment strategy and overall prognosis.