FDG PET-CT Scan Research Articles

7246 Cardiac Paraganglioma: A Rare Entity

Abstract Disclosure: L. Javed: None. L. Jonea: None. Cardiac paragangliomas are an exceptionally uncommon subset of neuroendocrine neoplasms. We present a case of a patient presenting with this condition. 70-year-old woman with pertinent past medical history of chronic veinous insufficiency complicated by recurrent abscesses of her right leg since venaseal procedure. The patient had positive IgG lambda on immunofixation that raised concerns for MGUS. Therefore, a F-18 FDG PET-CT scan was performed for further evaluation. PET-CT revealed a hypermetabolic mass in the upper inner right thigh and the right atrium (SUV 17.6) raising concern for septic thrombi. She was admitted in the hospital for initiation of antibiotic therapy. Transesophageal echocardiogram (TEE) revealed a 4.5 cm x 4.0 cm mass in the right atrioventricular (AV) groove region, extending over the root of the main pulmonary artery. Following discharge, despite completing six weeks of IV antibiotic therapy a CT scan on a subsequent clinic visit revealed the same mass as seen on TEE. CT imaging raised suspicion of neuroendocrine tumor. This led to referral to the endocrinology department. Laboratory results showed elevated normetanephrine and dopamine levels increasing likelihood of paraganglioma. Lab Results: 24 hr urine normetaneprhine :7197(N ≤ 376 mcg), 24 hr urinary dopamine :879 (N ≤400 mcg), 24 urinary metanephrine: 84 (N ≤96 mcg) & 24 hr urinary epinephrine <3 (N ≤20 mcg). Her home systolic blood pressure readings varied between 120’s & 170’s. She was initiated on Prazosin 1 mg daily in addition to the existing antihypertensive medications of nebivilol, amlodipine & furosemide. Few months later, this patient successfully underwent cardiac mass resection. Histologic findings of the resected mass were consistent with paraganglioma. Post-surgery, anti-hypertensive medications were discontinued, and blood pressure normalized to systolic readings in the 90s to 120s and diastolic readings in the 60s to 80s. Repeat biochemical tests indicated a normalization of normetanephrine & dopamine levels, validating the success of the resection. This case features an extremely rare entity cardiac paraganglioma that had an atypical clinical manifestation of being asymptomatic. Timely diagnosis and appropriate management are crucial for patient outcomes. Surgical intervention, although fundamental, bears significant risks, necessitating meticulous preoperative management to mitigate potential complications. The medical approach focuses on averting perioperative complications such as hypertensive crisis, cardiac arrhythmias and myocardial infarction. This is achieved by administering alpha and beta adrenoceptor blockers for a minimum of two weeks before the scheduled surgery. Regular follow up is also essential due to the unpredictable malignant potential of these tumors. Presentation: 6/3/2024

Role of F-18 FDG PET-CT in neuropsychiatric systemic lupus erythematosus

BackgroundNeuropsychiatric systemic lupus erythematosus (NPSLE) is a major contributor to morbidity and mortality in systemic lupus erythematosus (SLE) patients. To date no single clinical, laboratory or imaging test has proven accurate for NPSLE diagnosis which is a testament to the intricate and multifactorial pathophysiological mechanisms suspected to exist. Functional imaging with FDG PET-CT has shown promise in NPSLE diagnosis, detecting abnormalities prior to changes evident on anatomical imaging. Research indicates that NPSLE may be more aggressive in people of African descent with higher mortality rates, making rapid and correct diagnosis even more important in the African context. MethodsIn this narrative review, we provide a thorough appraisal of the current literature on the role of FDG PET-CT in NPSLE. Large, well-known databases were searched using appropriate search terms. Manual searches of references of retrieved literature were also included. FindingsA total of 73 article abstracts were assessed, yielding 26 papers that were directly relevant to the topic of FDG PET-CT in NPSLE. Results suggest that FDG PET-CT is a sensitive imaging test for NPSLE diagnosis and may play a role in assessing treatment response. It is complementary to routine anatomical imaging, particularly in diffuse manifestations of the disease. Newer quantitative analyses are commonly used for interpretation and can detect even subtle abnormalities, missed on visual inspection. Findings of group-wise analyses of FDG PET-CT scans in NPSLE patients are important in furthering our understanding of the complicated pathophysiological mechanisms involved. Limitations of FDG PET-CT include its lack of specificity, high cost and poor access. ConclusionFDG PET-CT is a sensitive test for NPSLE diagnosis but is hampered by lack of specificity. It is a valuable tool for clinicians managing SLE patients, particularly when anatomical imaging is negative. Its exact application will depend on the local context and clinical scenario.

Abstract 2585: First in human study with a novel peptide binder to glypican-3, demonstrates high specificity as a PET imaging agent in patients with hepatocellular carcinoma

Abstract Introduction: Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. The American Association for the Study of Liver Disease recommends surveillance for high-risk individuals with abdominal ultrasound, triple phase contrast CT or MRI. However, these imaging techniques have limited sensitivity in classifying lesions smaller than 2 centimeters. The use of [18F]FDG Positron Emission Tomography (PET) is constrained due to insufficient uptake by HCC lesions over background liver uptake. Hence, there is an urgent need for more precise radiotracers for HCC. This study introduces the development of a novel radiotracer that binds to glypican-3 (GPC3), a cell membrane-anchored oncofetal protein overexpressed in HCC with minimal normal tissue expression. Methods: [68Ga]Ga-RYZ-GPC3 is composed of a small macrocyclic peptide binder with high affinity to GPC3 linked with a tetraxetan moiety capable of chelating a variety of radioisotopes including positron-emitting 68Ga and other radiometals. The unlabeled binder to GPC3 was synthesized by the sponsor and provided to three imaging centers in India as part of investigator-initiated trials reviewed and approved by each site’s institutional review board and ethics committee. Labeling with 68Ga and quality checks of the product was performed locally at each center. Patients with high clinical suspicion or with confirmed HCC who gave informed consent received injections of 1.5-5.5 mCi of [68Ga]Ga-RYZ-GPC3 and underwent PET-CT scanning at predetermined intervals. Some patients underwent companion [18F]FDG PET-CT scans in accordance with local guidelines. Results: A total of 64 patients underwent [68Ga]Ga-RYZ-GPC3 PET-CT scans. The median age within the cohort was 61 (41-83), 22% were female. Liver cirrhosis was present in 72% of patients, attributed to hepatitis B, hepatitis C or NASH in 17%, 13% and 20% of cases. Notably, 92% of patients exhibited at least one positive lesion on [68Ga]Ga-RYZ-GPC3 scans. The median SUVmax of GPC3-avid liver lesions was 15.5 (range 1.1 to 137.0) while the median liver SUVmean was 1.6 (0.3-7.9). Physiologic uptake was predominantly observed in the kidneys, the primary route of clearance, with a median SUVmean of 10.9 (2.2-20.7). Additionally, 20 patients underwent [18F]FDG PET-CT scan for comparison. The median SUVmax of lesions on 68Ga-RYZ-GPC3 vs [18F]FDG PET was 11.0 (1.1-137.0) vs 3.8 (1.2-12.2). Conclusion: Early human imaging results in patients with HCC indicate that [68Ga]Ga-RYZ-GPC3 has high tumor lesion specificity compared to normal liverand demonstrates the potential of [68Ga]Ga-RYZ-GPC3 to improve detection of HCC over conventional [18F]FDG PET-CT. In addition, the binder could be complexed with a therapeutic radioisotope as a novel targeted therapeutic option for HCC. Further investigation of this first-in-class binder to HCC is warranted. Citation Format: Chandresakhar Bal, Sanjana Ballal, Kumar Kallur, Anna Karmann, Ye Yuan, Jessica Rearden, Kathryn Shah, Charlotte Lorenz, Susan Moran, Ken Song, Ishita Sen. First in human study with a novel peptide binder to glypican-3, demonstrates high specificity as a PET imaging agent in patients with hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2585.

Sequential deep learning image enhancement models improve diagnostic confidence, lesion detectability, and image reconstruction time in PET

BackgroundInvestigate the potential benefits of sequential deployment of two deep learning (DL) algorithms namely DL-Enhancement (DLE) and DL-based time-of-flight (ToF) (DLT). DLE aims to enhance the rapidly reconstructed ordered-subset-expectation-maximisation algorithm (OSEM) images towards block-sequential-regularised-expectation-maximisation (BSREM) images, whereas DLT aims to improve the quality of BSREM images reconstructed without ToF. As the algorithms differ in their purpose, sequential application may allow benefits from each to be combined. 20 FDG PET-CT scans were performed on a Discovery 710 (D710) and 20 on Discovery MI (DMI; both GE HealthCare). PET data was reconstructed using five combinations of algorithms:1. ToF-BSREM, 2. ToF-OSEM + DLE, 3. OSEM + DLE + DLT, 4. ToF-OSEM + DLE + DLT, 5. ToF-BSREM + DLT. To assess image noise, 30 mm-diameter spherical VOIs were drawn in both lung and liver to measure standard deviation of voxels within the volume. In a blind clinical reading, two experienced readers rated the images on a five-point Likert scale based on lesion detectability, diagnostic confidence, and image quality.ResultsApplying DLE + DLT reduced noise whilst improving lesion detectability, diagnostic confidence, and image reconstruction time. ToF-OSEM + DLE + DLT reconstructions demonstrated an increase in lesion SUVmax of 28 ± 14% (average ± standard deviation) and 11 ± 5% for data acquired on the D710 and DMI, respectively. The same reconstruction scored highest in clinical readings for both lesion detectability and diagnostic confidence for D710.ConclusionsThe combination of DLE and DLT increased diagnostic confidence and lesion detectability compared to ToF-BSREM images. As DLE + DLT used input OSEM images, and because DL inferencing was fast, there was a significant decrease in overall reconstruction time. This could have applications to total body PET.

Evaluating Outcome Prediction via Baseline, End-of-Treatment, and Delta Radiomics on PET-CT Images of Primary Mediastinal Large B-Cell Lymphoma.

Accurate outcome prediction is important for making informed clinical decisions in cancer treatment. In this study, we assessed the feasibility of using changes in radiomic features over time (Delta radiomics: absolute and relative) following chemotherapy, to predict relapse/progression and time to progression (TTP) of primary mediastinal large B-cell lymphoma (PMBCL) patients. Given the lack of standard staging PET scans until 2011, only 31 out of 103 PMBCL patients in our retrospective study had both pre-treatment and end-of-treatment (EoT) scans. Consequently, our radiomics analysis focused on these 31 patients who underwent [18F]FDG PET-CT scans before and after R-CHOP chemotherapy. Expert manual lesion segmentation was conducted on their scans for delta radiomics analysis, along with an additional 19 EoT scans, totaling 50 segmented scans for single time point analysis. Radiomics features (on PET and CT), along with maximum and mean standardized uptake values (SUVmax and SUVmean), total metabolic tumor volume (TMTV), tumor dissemination (Dmax), total lesion glycolysis (TLG), and the area under the curve of cumulative standardized uptake value-volume histogram (AUC-CSH) were calculated. We additionally applied longitudinal analysis using radial mean intensity (RIM) changes. For prediction of relapse/progression, we utilized the individual coefficient approximation for risk estimation (ICARE) and machine learning (ML) techniques (K-Nearest Neighbor (KNN), Linear Discriminant Analysis (LDA), and Random Forest (RF)) including sequential feature selection (SFS) following correlation analysis for feature selection. For TTP, ICARE and CoxNet approaches were utilized. In all models, we used nested cross-validation (CV) (with 10 outer folds and 5 repetitions, along with 5 inner folds and 20 repetitions) after balancing the dataset using Synthetic Minority Oversampling TEchnique (SMOTE). To predict relapse/progression using Delta radiomics between the baseline (staging) and EoT scans, the best performances in terms of accuracy and F1 score (F1 score is the harmonic mean of precision and recall, where precision is the ratio of true positives to the sum of true positives and false positives, and recall is the ratio of true positives to the sum of true positives and false negatives) were achieved with ICARE (accuracy = 0.81 ± 0.15, F1 = 0.77 ± 0.18), RF (accuracy = 0.89 ± 0.04, F1 = 0.87 ± 0.04), and LDA (accuracy = 0.89 ± 0.03, F1 = 0.89 ± 0.03), that are higher compared to the predictive power achieved by using only EoT radiomics features. For the second category of our analysis, TTP prediction, the best performer was CoxNet (LASSO feature selection) with c-index = 0.67 ± 0.06 when using baseline + Delta features (inclusion of both baseline and Delta features). The TTP results via Delta radiomics were comparable to the use of radiomics features extracted from EoT scans for TTP analysis (c-index = 0.68 ± 0.09) using CoxNet (with SFS). The performance of Deauville Score (DS) for TTP was c-index = 0.66 ± 0.09 for n = 50 and 0.67 ± 03 for n = 31 cases when using EoT scans with no significant differences compared to the radiomics signature from either EoT scans or baseline + Delta features (p-value> 0.05). This work demonstrates the potential of Delta radiomics and the importance of using EoT scans to predict progression and TTP from PMBCL [18F]FDG PET-CT scans.

18-F FDG PET/CT in a Case of Recurrent Pericardial Effusion Diagnosed as Cardiac Sarcoma.

Recurrent pericardial effusion poses a diagnostic challenge, especially in young patients. We present a case of a 22-year-old female who experienced recurrent pericardial effusion and cardiac tamponade. Despite initial treatment with anti-tubercular drugs and prednisolone, the patient had a relapse of symptoms, necessitating further investigation. Imaging studies revealed massive pericardial effusion with septations, suggestive of constrictive pericarditis with impending cardiac tamponade. To establish a definitive diagnosis, the patient underwent an FDG PET-CT scan after adhering to a specific dietary regimen. The scan revealed an ill-defined mediastinal mass with high metabolic activity, along with a gross pericardial effusion showing metabolic activity in the periphery and septations. Subsequent biopsy of the mediastinal mass confirmed a diagnosis of high-grade sarcoma.Primary malignant cardiac tumors are rare, and their prognosis is generally poor due to limited treatment options. While echocardiography and MRI are commonly used imaging techniques, FDG PET-CT is not routinely employed for evaluating cardiac tumors. However, in this case, FDG PET-CT played a crucial role in identifying the mediastinal mass and confirming the diagnosis.Early detection and accurate diagnosis of cardiac tumors are vital for initiating appropriate treatment strategies. Further studies are needed to explore the utility of FDG PET-CT in the evaluation of cardiac tumors, especially in cases of recurrent pericardial effusion.

Evaluating Treatment Response in Breast Cancer: A Case Report on Static Metastatic Disease on Bone Scans

Background: We report a case of a 54-year-old female patient with carcinoma of the left breast with persistent methylene diphosphonate (MDP) uptake in sclerotic osseous lesions. These lesions were finally declared treated osseous metastatic lesions due to non-avidity on the F18 FDG PET-CT scan, normalization of CA-15.3, and resolution of bone pains. To the best of our knowledge, this has not been reported previously. Case presentation: A 54-year-old woman with persistent backache was referred for further evaluation by a Tc99m MDP bone scan. A Tc-99mmMDP bone scan showed wide-spread skeletal metastatic disease. Magnetic resonance imaging (MRI) showed extensive marrow disease involving the spine and iliac bones. A bone marrow biopsy revealed metastatic carcinoma with a tumor phenotype favoring breast primary. On further workup, the patient was diagnosed with invasive ductal carcinoma of the left breast and was treated with cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors along with hormone therapy and bisphosphonates, followed by radiation therapy for bone metastasis. The skeletal metastatic disease remains static on three consecutive Tc99m MDP bone scans, despite the clinical improvement and decreased tumor marker levels. The F18-FDG-FDG-CT scan done for monitoring treatment response revealed multiple non-avid sclerotic osseous lesions, favoring treatment response. The patient was continued with the same treatment, and a follow-up Tc99m MDP bone scan after 6 months revealed no interval change in the reported lesions compared to the initial scan. However, a synergistically performed F18 FDG PET-CT scan again showed multiple non-avid sclerotic osseous lesions suggestive of treated metastasis. Conclusion: This case highlights the importance of 18F-FDG PET-CT in evaluating the treatment response, especially in patients with symptomatic improvement and falling tumor marker levels with static disease on repeated Tc99m MDP bone scans.

Detection of Primary Hepatocellular Carcinoma on 18F-Fluorodeoxyglucose Positron Emission Tomography-computed Tomography.

Hepatocellular carcinoma (HCC), ranks as the third most prevalent malignancy contributing to cancer-related death on a global scale. Hepatocellular carcinoma is known to be the fifth most frequently diagnosed malignancy of the males while among females, it is ranked as the seventh most common malignancy. The study was conducted to detect the sensitivity of primary HCC using 18F-flourodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) scan. This prospective study was conducted to identify the primary HCC in a sample size of 51 patients, in whom FDG PET-CT scan was performed between May 2022 and December 2022. Among the cohort of 51 patients, primary HCC was detected on FDG PET-CT in 43 individuals representing true-positive cases. Conversely, FDG PET-CT was unable to detect HCC in 8 cases, representing false-negative. Out of 51 patients, 74.5% of HCC cases exhibited multifocal pattern. The maximum standardized uptake value (SUV max) of the primary malignant site ranged from 1.9 to 16.1, with a mean of 3.7 ± 2.8. The FDG PET-CT revealed abnormal sites of the uptake outside liver in 23 individuals. The research confirmed the tumor recurrence in four previously treated patients. In the conducted investigation, FDG PET-CT showed 84.3% sensitivity for the diagnosis of HCC. The study demonstrates that FDG PET-CT is a viable option for the detection of HCC. The sensitivity of FDG PET-CT in our population is comparable and in agreement with international data for diagnosis of HCC thereby favoring its reproducibility among geographical and ethnic groups. However, owing to the reduced ability of FDG PET-CT scan to identify well-differentiated/low-grade HCC, the routine use of FDG PET-CT scan may not be considered in cases requiring evaluation of primary disease only. Arshad K, Hanan SD, Younis MN, et al. Detection of Primary Hepatocellular Carcinoma on 18F-Fluorodeoxyglucose Positron Emission Tomography-computed Tomography. Euroasian J Hepato-Gastroenterol 2023;13(2):66-72.

Quantitative and clinical implications of the EARL2 versus EARL1 [18F]FDG PET-CT performance standards in head and neck squamous cell carcinoma

BackgroundThe EANM Research Ltd. (EARL) guidelines give recommendations for harmonization of [18F]FDG PET-CT image acquisition and reconstruction, aiming to ensure reproducibility of quantitative data between PET scanners. Recent technological advancements in PET-CT imaging resulted in an updated version of the EARL guidelines (EARL2). The aim of this study is to compare quantitative [18F]FDG uptake metrics of the primary tumor and lymph nodes in patients with head and neck squamous cell carcinoma (HNSCC) on EARL2 versus EARL1 reconstructed images and to describe clinical implications for nodal staging and treatment.MethodsForty-nine consecutive patients with HNSCC were included. For all, both EARL1 and EARL2 images were reconstructed from a singular [18F]FDG PET-CT scan. Primary tumors and non-necrotic lymph nodes ≥ 5 mm were delineated on CT-scan. In the quantitative analysis, maximum standardized uptake values (SUVmax) and standardized uptake ratios (SURmax, i.e., SUVmax normalized to cervical spinal cord uptake) were calculated for all lesions on EARL1 and EARL2 reconstructions. Metabolic tumor volume (MTV) and total lesion glycolysis were compared between EARL1 and EARL2 using different segmentation methods (adaptive threshold; SUV2.5/3.5/4.5; SUR2.5/3.5/4.5; MAX40%/50%). In the qualitative analysis, each lymph node was scored independently by two nuclear medicine physicians on both EARL1 and EARL2 images on different occasions using a 4-point scale.ResultsThere was a significant increase in SUVmax (16.5%) and SURmax (9.6%) of primary tumor and lymph nodes on EARL2 versus EARL1 imaging (p < 0.001). The proportional difference of both SUVmax and SURmax between EARL2 and EARL1 decreased with increasing tumor volume (p < 0.001). Absolute differences in MTVs between both reconstructions were small (< 1.0 cm3), independent of the segmentation method. MTVs decreased on EARL2 using relative threshold methods (adaptive threshold; MAX40%/50%) and increased using static SUV or SUR thresholds. With visual scoring of lymph nodes 38% (11/29) of nodes with score 2 on EARL1 were upstaged to score 3 on EARL2, which resulted in an alteration of nodal stage in 18% (6/33) of the patients.ConclusionsUsing the EARL2 method for PET image reconstruction resulted in higher SUVmax and SURmax compared to EARL1, with nodal upstaging in a significant number of patients.

Primary Thyroid Lymphoma: A Rare Case Revealed by a Goiter

Primary thyroid lymphoma (PTL) is an exceptionally rare malignant tumor originating in the thyroid gland, comprising just 5% of thyroid malignancies and 2% of extranodal lymphomas. Its clinical presentation is unspecific, and diagnosis relies on histological examination. We describe a case of a 70-year-old woman with a swiftly enlarging anterior neck swelling causing dyspnea and dysphagia over six months, alongside weight loss and anorexia. Clinical examination unveiled a painless, constricting goiter with cervical adenopathy. Ultrasonography revealed a multi-heteronodular goiter with a suspicious left loboishmic nodule. CT and 18 FDG PET-CT scans indicated an intensely hypermetabolic cervical tumor infiltrating the thyroid and extending into the thoracic region with lymph node and bone involvement, suggesting high-grade lymphoma. The patient underwent total thyroidectomy and lymph node dissection, followed by favorable outcomes after polychemotherapy. PTL is an uncommon cause of thyroid malignancy and extranodal lymphomas. It should be suspected in patients presenting with a growing neck mass, particularly in those with a history of Hashimoto's thyroiditis. Although certain ultrasound features may suggest PTL, a biopsy remains the definitive diagnostic tool. The most prevalent PTL subtype is diffuse large B-cell lymphoma (DLBCL), constituting over 50% of cases. Treatment and outcomes hinge on both stage and histological subtype. Radiation and chemotherapy are the primary treatments, given PTL's sensitivity to these modalities. Localized, less aggressive lymphomas can be treated with radiation alone, while disseminated or aggressive subtypes may require combined modality treatment (CMT). Surgery is an option when patients experience compressive symptoms or airway obstruction. Prognosis varies depending on factors like stage and histological subtype, underscoring the need for personalized management. In summary, PTL necessitates a multidisciplinary approach for .....

Calcaneus metastasis: a rare presentation of poorly differentiated thyroid cancer.

A 60-year-old woman presented to our clinic with an acute onset 3 months history of right ankle pain. The patient had a history of poorly differentiated thyroid cancer, which was treated with total thyroidectomy, left lateral neck dissection levels II-V and central neck dissection levels VI-VII followed by postoperative I-131 radioactive iodine (131I) ablation therapy 3.7 GBq 6 months ago. The post-131I WBS showed residual iodine-avid thyroid tissue with no other iodine-avid disease or metastasis. SPECT/CT of the neck and chest showed nonavid bilateral pulmonary nodules, discrete nodal masses in mediastinum and nonavid bone lesions. FDG-PET CT scan showed FDG-avid mediastinal lymph nodes (LN), innumerable non-FDG-avid subcentimetric pulmonary nodules and few FDG-avid lytic lesions in the skeleton. X-ray and MRI of the right ankle showed a well-marginated lytic lesion in the posterior body of calcaneus and 5 × 6 cm soft tissue mass lesion, respectively. The histopathology of the calcaneus mass confirmed a positive immunostaining for thyroid origin which includes thyroglobulin and TTF-1 with PAX-8. Endobronchial mediastinal and bronchial LN biopsy confirmed thyroid cancer metastasis. Gene mutation showed HRAS and GNA13 with a high tumor mutational burden. We describe a rare case of poorly differentiated thyroid cancer in a patient who presented with right ankle pain; we confirmed the cause to be a calcaneus metastasis from the thyroid cancer, with calcaneus being an extremely rare site for bone metastases. Gene mutations points toward treatment with immune checkpoint inhibitors. Poorly differentiated thyroid carcinoma (PDTC) usually metastasizes to lung and bone but can rarely occur in the calcaneus. Patients with distant metastases have significantly worse long-term prognosis. Radiotherapy is effective in reducing the metastatic pains as well as reducing the size of the metastasis. PAX-8 staining can be used to differentiate thyroid carcinomas from lung adenocarcinomas. The importance of searching for gene mutations to decide the treatment of PDTC.

A Novel FDG PET and Mean Lung Dose Model to Identify Stage III NSCLC Patients at High Risk of Developing Early Radiation Pneumonitis

Early radiation pneumonitis (RPEarly) is a primary reason for the premature discontinuation of durvalumab consolidation and can lead to poor survival in patients with stage III non-small cell lung cancer (NSCLC). Currently, there are no RP risk models specifically tested for RPEarly. Here, we tested the applicability of published RP models for predicting RPEarly and explored the value of integrating pretreatment FDG-PET parameters. The cohort consisted of all 178 LA-NSCLC patients treated with concurrent chemoradiation (cCRT) and durvalumab between May 2017 and December 2021. RPEarly was defined as RP occurring within three months of cCRT completion; late RP (RPLate) was defined as any later occurring RP. The three published RP models analyzed included: 1) Mean lung dose (MLD), 2) MLD, age, pulmonary comorbidity, smoking status, and tumor location, and 3) MLD, age and pulmonary comorbidity. In addition, pretreatment FDG PET-CT scans were used to calculate SUV parameters from auto-segmented normal lung contours: 10th- and 90th percentile (SUVP10, SUVP90), maximum, mean (SUVmean), minimum, and standard deviation. The RP models were fit to RPEarly, RPLate, and RPEarly+Late in the 178 patients. To assess the association between FDG PET parameters and RP unbiasedly, the cohort was then randomly split, but enforcing similar RP rates, into a two-thirds derivation and a one-third validation subset. Model performance was assessed by AUC, p-values and the Hosmer-Lemeshow test (pHL; ideally ∼0.50). The rates of RPEarly, RPLate, and RPEarly+Late were 12%, 11%, and 23%, respectively (corresponding to 21, 20, and 41 events). Only the MLD model significantly predicted RPEarly (AUC = 0.70; p = 0.04; pHL = 0.84); none of the three models predicted RPLate or RPEarly+Late. Among the FDG PET parameters, SUVP10, SUVP90 and SUVmean predicted RPEarly with similar performance (AUC = 0.69-0.73; p = 0.005-0.01; pHL = 0.68-0.72), and, therefore, bivariate models were built between MLD and each of SUVP10, SUVP90 and SUVmean. Only the MLD + SUVP90 model generalized in the validation subset (AUC = 0.63; p = 0.03; pHL = 0.89) and was thus deemed the final model for RPEarly. A final re-fitting of all model coefficients to the whole cohort indicated improvement over using the published MLD alone model (AUC = 0.75 vs. 0.70; p-value = 0.0006 vs. 0.04; pHL = 0.67 vs. 0.84). Risk of RPEarly is thus estimated as: RPEarly = 1/(1 = e-x); x = -5.79 + (1.57*MLD) + (0.14* SUVP90). Patients at risk for RPEarly can be accurately identified prior to treatment by combining a re-fitted version of the published Mean Lung Dose model and pre-treatment FDG PET SUVP90 of the normal lung. This refined model can be used to identify patients with an exacerbated risk for premature durvalumab discontinuation due to RPEarly and could allow for interventions and/or the generation of "RPEarly sparing" treatment plans to improve overall treatment outcomes.

Evaluation of treatment response by Hopkins criteria on 18 F FDG PET-CT in patients of non-small cell lung cancer and its comparison with PERCIST response criteria.

To assess treatment response on FDG PET-CT in NSCLC patients by visual Hopkins score compared to PERCIST criteria and its potential for prognostication (or its correlation with survival). Forty-four NSCLC patients with baseline and post-treatment FDG PET-CT scans were included, and interpreted using Hopkins and PERCIST criteria classifying patients into responders and non-responders. PERCIST-based CMR and PMR, and Hopkins Scores 1,2,3 were classified responders. PERCIST-based SD and PD and Hopkins scores 4,5 were classified as non-responders. Patients were followed upto 24 months after treatment completion. Cohen kappa for inter-criteria agreement and Kaplan Meir curve for overall survival (OS) analysis done. Out of 44 patients, PERCIST classified 27 (61.3%) as responders and 17 (38.6%) as non-responders, whereas Hopkins classified 12 patients (27.3%) as responders and 32 (72.7%) as non-responders. Inter-criteria agreement was low (kappa=0.19) with discordance in 45.5% of patients. Eighteen of 20 discordant cases were non-responders on Hopkins and responders on PERCIST, of which 88.8% were non-responders on follow-up as predicted by Hopkins. PERCIST responders had OS of 96.4% and 64.3% at 9 and 24 months, respectively, while non-responders OS was 93.5% and 40.2% at 9 and 24 months, respectively ( P -value = 0.049). However, responders on Hopkins had OS of 100% at 24 months, whereas non-responders had OS of 93.5% and 51.5% at 9 and 24 months, respectively ( P -value = 0.232). Semi-quantitative PERCIST and visual Hopkins criteria show low inter-criteria agreement, with visual criteria better-predicting survival in patients of NSCLC.

Role of F-18 FDG PET-CT in Follow up Patients with Rectal Carcinoma: Single Institute Based Study

Introduction: F-18 Fluorodeoxyglucose Positron Emission Tomography (18F-FDG PET/CT) is a hybrid non-invasive imaging tool that integrates PET and CT into a single imaging device. It is used to detect and measure metabolic activity in a cancer cell and, hence, can provide anatomic and metabolic information. 18F-FDG PET/CT is useful for the detection of loco-regional recurrence, distant metastases, and monitoring therapy response in patients with rectal carcinoma. This study was done to see the usefulness of 18F-FDG PET/CT in the follow-up evaluation of patients with rectal carcinoma. Materials and Methods: This retrospective study was done in the PET/CT division of the National Institute of Nuclear Medicine &amp; Allied Sciences (NINMAS) between January 2021 and December 2022. A total of 26 patients with rectal carcinoma, requested for an F-18 FDG PET-CT scan were enrolled in this study. Image findings were analyzed and properly documented in a predesigned format to evaluate the results. Results: Total 26 patients with an average age of 47.69 and a follow up period of 6 months to 5 years were enrolled in this study. Histologically adenocarcinoma was seen in 21 patients, four patients were mucinous, two were papillary, and carcinoid tumor was found in one patient. On PET/CT imaging, no metastases were found in 17 (65.4%) out of 26 patients and metastases was seen in 9 (34.6%) patients. Among them four (44.5%) had lung, two (22.2%) had lymph nodes, one (11.1%) had liver and lymph node metastases, one (%11.1) had skeletal metastases, and one (11.1%) had peritoneal metastases. No significant association was observed with histopathology or treatment protocol. CEA was higher in patients with metastases and lower in those without. Conclusion: 18F-FDG PET/CT is an effective tool in follow up patients with rectal carcinoma as it can accurately detect locoregional recurrence or distant metastases. Bangladesh J. Nuclear Med. 25(2): 105-109, 2022

Prediction of 2-[18F]FDG PET-CT SUVmax for Adrenal Mass Characterization: A CT Radiomics Feasibility Study

Background: Indeterminate adrenal masses (AM) pose a diagnostic challenge, and 2-[18F]FDG PET-CT serves as a problem-solving tool. Aim of this study was to investigate whether CT radiomics features could be used to predict the 2-[18F]FDG SUVmax of AM. Methods: Patients with AM on 2-[18F]FDG PET-CT scan were grouped based on iodine contrast injection as CT contrast-enhanced (CE) or CT unenhanced (NCE). Two-dimensional segmentations of AM were manually obtained by multiple operators on CT images. Image resampling and discretization (bin number = 16) were performed. 919 features were calculated using PyRadiomics. After scaling, unstable, redundant, and low variance features were discarded. Using linear regression and the Uniform Manifold Approximation and Projection technique, a CT radiomics synthetic value (RadSV) was obtained. The correlation between CT RadSV and 2-[18F]FDG SUVmax was assessed with Pearson test. Results: A total of 725 patients underwent PET-CT from April 2020 to April 2021. In 150 (21%) patients, a total of 179 AM (29 bilateral) were detected. Group CE consisted of 84 patients with 108 AM (size = 18.1 ± 4.9 mm) and Group NCE of 66 patients with 71 AM (size = 18.5 ± 3.8 mm). In both groups, 39 features were selected. No statisticallyf significant correlation between CT RadSV and 2-[18F]FDG SUVmax was found (Group CE, r = 0.18 and p = 0.058; Group NCE, r = 0.13 and p = 0.27). Conclusions: It might not be feasible to predict 2-[18F]FDG SUVmax of AM using CT RadSV. Its role as a problem-solving tool for indeterminate AM remains fundamental.

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.

Clinical Response and Safety of Alternating Daily Dosage of Crizotinib due to Side Effects in Advanced NSCLC patient harboring ROS1-rearrangement: A Case Report

Background: Advanced lung cancer has the lowest overall survival than other stage and tyrosine kinase inhibitor (TKI) are promising to prolong life and prevent disease progression. ROS1 rearrangement was very rare and constitute around 1.4 % of all NSCLC. Previous preclinical and clinical trial have reported the efficacy and safety of crizotinib against advanced NSCLC with ROS1 rearrangement, but little is known about its efficacy with nonstandard dosage.Case: A female, 58 years old, with no history of cancer nor smoking, came with persistent chest pain and cough for three months. The patient was then diagnosed with advanced lung cancer by FDG-PET CT Scan. The biopsy confirmed adenocarcinoma with genotyped ROS1-rearrangement. After receive standar dose of 200 mg bid, the patient intolerated and treatment plan was adjusted with 200 mg of alternated daily dosage (one-day on-off drug administration). Fortunately, the intolerance symptoms were alleviated and showed positive response during 3-years therapy.Discussion: Pulmonary tuberculosis has been linked to pneumothorax in HIV-associated TB patients. This study is done to better our understanding of the link between the two. The patient had active pulmonary tuberculosis as well as HIV and a rare case of bilateral pneumothorax in the ER.Conclusion: This case showed that advanced NSCLC with ROS1 rearrangement has positive response to crizotinib despite using alternating daily dose, with good response during 3 years and on.

The validation of low-dose CT scans from the [18F]-FDG PET-CT scan to assess skeletal muscle mass in comparison with diagnostic neck CT scans

PurposeRadiologically defined sarcopenia, or a low skeletal muscle index (SMI), is an emerging biomarker for adverse clinical outcomes in head and neck cancer (HNC) patients. Recently, SMI measurements have been validated at the level of the third cervical vertebra (C3) on diagnostic neck CT scans but are not yet validated on low-dose (LD) neck CT scans from the [18F]-FDG PET-CT. This hampers SMI analysis in HNC patients without a diagnostic neck CT but with a [18F]-FDG PET-CT scan. Therefore, the aim was to study whether (low) SMI based on LD CT scan from [18F]-FDG PET-CT is comparable to those derived from diagnostic neck CT scans.MethodsHNC patients with both diagnostic CT and [18F]-FDG PET-CT of the neck were prospectively included into the OncoLifeS data-biobank. Skeletal muscle was retrospectively delineated at the level of the third cervical vertebra (C3), and (low) SMI (cm2/m2) was calculated for diagnostic and LD neck CTs. (Low) SMI from the diagnostic neck CT was considered the reference standard. Intra-class correlation coefficient (ICC), Bland–Altman plots, and Cohen’s Kappa analysis were performed.ResultsThe cohort (n = 233) mean age was 66.2 ± 12.8 years, and 74.2% of patients were male. Inter-rater reliability was excellent (ICC > 0.990, 95% confidence interval 0.975–0.996, p < 0.001). The agreement of SMI between both modalities was high according to the Bland–Altman plot (mean ΔSMI = − 0.19 cm2/m2), and there was no substantial bias. Cohen’s Kappa analysis showed an almost perfect agreement of low SMI between the two modalities (κ = 0.911, p < 0.001). The position of arms didn't affect the high agreement of (low) SMI.ConclusionSkeletal muscle mass, as measured with (low) SMI, remains constant irrespective of CT acquisition parameters (diagnostic neck CT scans versus LD neck scans of the [18F]-FDG PET-CT scan), positioning of arms, and observers. These findings contribute to the construction of a clinically useful radiological biomarker for SMI and therefore identify patients at risk for adverse clinical outcomes.

Earlier Recurrence Detection Using Routine FDG PET-CT Scans in Surveillance of Stage IIB to IIID Melanoma: A National Cohort Study of 1480 Patients.

The effect of routine imaging in melanoma surveillance is unknown. In 2016, Denmark was the first country in the world to implement routine imaging with positron emission tomography-computed tomography with fluorodeoxyglucose (FDG PET-CT) in a nationwide, population-based surveillance program.This study aimed to determine the impact of surveillance with routine FDG PET-CT on hazard, cumulative incidence, and absolute risk of overall, locoregional, and distant recurrence detection in patients with stage IIB to IIID cutaneous melanoma. This retrospective, population-based, nationwide cohort study used prospectively collected data from five national health registries to compare hazard, cumulative incidence, and absolute risk of recurrence in patients with cutaneous melanoma diagnosed in 2008-2010 (cohort 1, followed with clinical examinations) and patients with cutaneous melanoma diagnosed in 2016-2017 (cohort 2, followed with clinical examinations and routine FDG PET-CT at 6, 12, 24, and 36 months). The study included 1480 patients with stage IIB to IIID cutaneous melanoma. Cumulative incidences of overall and distant recurrence were higher in cohort 2, with a peak difference at three years (32.3 % vs 27.5 % and 25.8 % vs. 18.5 %, respectively). The hazard of recurrence was higher in cohort 2 during the first two years, with hazard rates for overall and distant recurrence of 1.16 (95% confidence interval [CI], 0.93-1.44) and 1.51 (95 % CI, 1.16-1.96), respectively. The patterns persisted in absolute risk estimates. Patients with stage IIB to IIID melanoma followed with routine FDG PET-CT had a 51 % increased hazard of distant recurrence detection within the first two years of surveillance. Future studies must determine whether this earlier recurrence detection translates into improved survival.

Qualitative and Semiquantitative Parameters of 18F-FDG-PET/CT as Predictors of Malignancy in Patients with Solitary Pulmonary Nodule

This study aims to evaluate the reliability of qualitative and semiquantitative parameters of 18F-FDG PET-CT, and eventually a correlation between them, in predicting the risk of malignancy in patients with solitary pulmonary nodules (SPNs) before the diagnosis of lung cancer. A total of 146 patients were retrospectively studied according to their pre-test probability of malignancy (all patients were intermediate risk), based on radiological features and risk factors, and qualitative and semiquantitative parameters, such as SUVmax, SUVmean, TLG, and MTV, which were obtained from the FDG PET-CT scan of such patients before diagnosis. It has been observed that visual analysis correlates well with the risk of malignancy in patients with SPN; indeed, only 20% of SPNs in which FDG uptake was low or absent were found to be malignant at the cytopathological examination, while 45.45% of SPNs in which FDG uptake was moderate and 90.24% in which FDG uptake was intense were found to be malignant. The same trend was observed evaluating semiquantitative parameters, since increasing values of SUVmax, SUVmean, TLG, and MTV were observed in patients whose cytopathological examination of SPN showed the presence of lung cancer. In particular, in patients whose SPN was neoplastic, we observed a median (MAD) SUVmax of 7.89 (±2.24), median (MAD) SUVmean of 3.76 (±2.59), median (MAD) TLG of 16.36 (±15.87), and a median (MAD) MTV of 3.39 (±2.86). In contrast, in patients whose SPN was non-neoplastic, the SUVmax was 2.24 (±1.73), SUVmean 1.67 (±1.15), TLG 1.63 (±2.33), and MTV 1.20 (±1.20). Optimal cut-offs were drawn for semiquantitative parameters considered predictors of malignancy. Nodule size correlated significantly with FDG uptake intensity and with SUVmax. Finally, age and nodule size proved significant predictors of malignancy. In conclusion, considering the pre-test probability of malignancy, qualitative and semiquantitative parameters can be considered reliable tools in patients with SPN, since cut-offs for SUVmax, SUVmean, TLG, and MTV showed good sensitivity and specificity in predicting malignancy.