Fluorodeoxyglucose Activity Research Articles

Feasibility of Biology-guided Radiotherapy (BgRT) Targeting Fluorodeoxyglucose (FDG) avid liver metastases

IntroductionBiology-guided radiotherapy (BgRT) is a novel radiation delivery approach utilizing fluorodeoxyglucose (FDG) activity on positron emission tomography (PET) imaging performed in real-time to track and direct RT. Our institution recently acquired the RefleXion X1 BgRT system and sought to assess the feasibility of targeting metastatic sites in various organs, including the liver. However, in order for BgRT to function appropriate, adequate contrast in FDG activity between the tumor and the background tissue, referred to as the normalized SUV (NSUV), is necessary for optimal functioning of BgRT.MethodsWe reviewed the charts of 50 lung adenocarcinoma patients with liver metastases. The following variables were collected: SUVmax and SUVmean for each liver metastasis, SUVmean and SUVmax at 5 and 10 mm radially from the lesion, and NSUV at 5 mm and 10 mm (SUVmax of the liver metastasis divided by SUV mean at 5 mm at 10 mm respectively).Results82 measurable liver metastases were included in the final analysis. The average SUVbackground of liver was 2.26 (95% confidence interval [CI] 2.17–2.35); average SUVmean for liver metastases was 5.31 (95% CI 4.87–5.75), and average SUVmax of liver metastases was 9.19 (95% CI 7.59–10.78). The average SUVmean at 5 mm and 10 mm radially from each lesion were 3.08 (95% CI 3.00-2.16) and 2.60 (95% CI 2.52–2.68), respectively. The mean NSUV at 5 mm and 10 mm were 3.13 (95% CI 2.53–3.73) and 3.69 (95% CI 3.00-4.41) respectively. Furthermore, 90% of lesions had NSUV greater than 1.45 at 5 mm and greater than 1.77 at 10 mm.ConclusionsThis is the first study to comprehensively characterize FDG contrast between the liver tumor and background, referred to as NSUV. Due to the high background SUV normally found in the liver, this work will be valuable for guiding optimization of BgRT for treating liver metastases in the future using the RefleXion® X1 and potentially other similar BgRT platforms.

Anaplastic Thyroid Carcinoma versus Metastatic SCC: A Diagnostic Dilemma in a Rare Presentation of Post-Radiation Thyroid Swelling

AbstractA 71-year-old male with type 2 diabetes and hypertension was diagnosed with carcinoma of the pyriform fossa in 2019. The biopsy was reported as a moderately differentiated squamous cell carcinoma, and positron emission tomography-computed tomography (PET-CT) scan showed an fluorodeoxyglucose (FDG)-avid lesion in the pyriform fossa and the aryepiglottic fold with few nodes in level II and level III. The paitent was treated with radical chemoradiotherapy. A follow-up PET-CT scan done in 2022 revealed an FDG-avid soft tissue thickening in the left palatine tonsillar region and an uptake in the thyroid that was reported as not significant. A punch biopsy from the tonsillar fossa lesion revealed squamous cell carcinoma. The lesion was treated as a second primary and treated with radiotherapy with curative intent. The patient was complaining of dysphagia, difficulty in breathing, and weight loss around 6 months after treatment that were addressed medically. There was a significant reduction in size and FDG activity of the ill-defined thickening in the left tonsillar region which was seen in the response-assessment PET done 6 months after RT. A heterogeneously enhancing nodules were seen in both lobes of the thyroid in which the largest one measured 3.5 × 3.1 cm seen in the right lobe. The patient underwent a biopsy from the thyroid that revealed a benign thyroid gland infiltrated by clusters and nests of poorly differentiated malignant cells. The histomorphology was suggestive of a poorly differentiated carcinoma, likely anaplastic carcinoma thyroid, or metastasis of the squamous cell carcinoma. Curative treatment was ruled out in this case due to his comorbidities, pulmonary symptoms, and radiation delivered to the neck.

Low 18F-fluorodeoxyglucose dose positron emission tomography assisted by a deep-learning image-denoising technique in patients with lymphoma.

Patients with lymphoma receive multiple positron emission tomography/computed tomography (PET/CT) exams for monitoring of the therapeutic response. With PET imaging, a reduced level of injected fluorine-18 fluorodeoxyglucose ([18F]FDG) activity can be administered while maintaining the image quality. In this study, we investigated the efficacy of applying a deep learning (DL) denoising-technique on image quality and the quantification of metabolic parameters and Deauville score (DS) of a low [18F]FDG dose PET in patients with lymphoma. This study retrospectively enrolled 62 patients who underwent [18F]FDG PET scans. The low-dose (LD) data were simulated by taking a 50% duration of routine-dose (RD) PET list-mode data in the reconstruction, and a U-Net-based denoising neural network was applied to improve the images of LD PET. The visual image quality score (1 = undiagnostic, 5 = excellent) and DS were assessed in all patients by nuclear radiologists. The maximum, mean, and standard deviation (SD) of the standardized uptake value (SUV) in the liver and mediastinum were measured. In addition, lesions in some patients were segmented using a fixed threshold of 2.5, and their SUV, metabolic tumor volume (MTV), and tumor lesion glycolysis (TLG) were measured. The correlation coefficient and limits of agreement between the RD and LD group were analyzed. The visual image quality of the LD group was improved compared with the RD group. The DS was similar between the RD and LD group, and the negative (DS 1-3) and positive (DS 4-5) results remained unchanged. The correlation coefficients of SUV in the liver, mediastinum, and lesions were all >0.85. The mean differences of SUVmax and SUVmean between the RD and LD groups, respectively, were 0.22 [95% confidence interval (CI): -0.19 to 0.64] and 0.02 (95% CI: -0.17 to 0.20) in the liver, 0.13 (95% CI: -0.17 to 0.42) and 0.02 (95% CI: -0.12 to 0.16) in the mediastinum, and -0.75 (95% CI: -3.42 to 1.91), and -0.13 (95% CI: -0.57 to 0.31) in lesions. The mean differences in MTV and TLG were 0.85 (95% CI: -2.27 to 3.98) and 4.06 (95% CI: -20.53 to 28.64) between the RD and LD groups. The DL denoising technique enables accurate tumor assessment and quantification with LD [18F]FDG PET imaging in patients with lymphoma.

BIOGUIDE-X: A First-in-Human Study of the Performance of Positron Emission Tomography-Guided Radiation Therapy

Positron emission tomography (PET)-guided radiation therapy is a novel tracked dose delivery modality that uses real-time PET to guide radiation therapy beamlets. The BIOGUIDE-X study was performed with sequential cohorts of participants to (1) identify the fluorodeoxyglucose (FDG) dose for PET-guided therapy and (2) confirm that the emulated dose distribution was consistent with a physician-approved radiation therapy plan. This prospective study included participants with at least 1 FDG-avid targetable primary or metastatic tumor (2-5 cm) in the lung or bone. For cohort I, a modified 3 + 3 design was used to determine the FDG dose that would result in adequate signal for PET-guided therapy. For cohort II, PET imaging data were collected on the X1 system before the first and last fractions among patients undergoing conventional stereotactic body radiation therapy. PET-guided therapy dose distributions were modeled on the patient's computed tomography anatomy using the collected PET data at each fraction as input to an "emulated delivery" and compared with the physician-approved plan. Cohort I demonstrated adequate FDG activity in 6 of 6 evaluable participants (100.0%) with the first injected dose level of 15 mCi FDG. In cohort II, 4 patients with lung tumors and 5 with bone tumors were enrolled, and evaluable emulated delivery data points were collected for 17 treatment fractions. Sixteen of the 17 emulated deliveries resulted in dose distributions that were accurate with respect to the approved PET-guided therapy plan. The 17th data point was just below the 95% threshold for accuracy (dose-volume histogram score = 94.6%). All emulated fluences were physically deliverable. No toxicities were attributed to multiple FDG administrations. PET-guided therapy is a novel radiation therapy modality in which a radiolabeled tumor can act as its own fiducial for radiation therapy targeting. Emulated therapy dose distributions calculated from continuously acquired real-time PET data were accurate and machine-deliverable in tumors that were 2 to 5 cm in size with adequate FDG signal characteristics.

Abstract P2-03-17: Fluoroestradiol (FES) and Fluorodeoxyglucose (FDG) PET imaging in patients with ER+, HER2+ or HER2- metastatic breast cancer

Abstract Background: 18F-Fluorodeoxyglucose (FDG) has long been used for measuring tumor glycolytic activity in clinical PET imaging. The FDA recently approved 18F-Fluoroestradiol (FES) (Cerianna) as a PET imaging tracer for characterizing disease in patients with estrogen-receptor positive (ER+) breast cancer. As FES PET enters clinical practice it is important to establish its utility in the full population of hormone-receptor positive patients, including for patients with human epidermal growth factor 2 (HER2)-overexpressing tumors. Patients with HER2-positive metastatic breast cancer have historically been treated with combination cytotoxic and HER2-directed therapy, with the understanding that HER2 is the primary driver in this disease state. This retrospective study examined uptake in matched lesions for both FES and FDG PET and compared activity in patients with HER2 positive versus HER2 negative metastatic breast cancer. Methods: Patients were selected from the UW research database who had a history of biopsy-proven primary ER+ breast cancer as well as FES and FDG PET scans within 30 days. We examined FDG and FES scans and recorded SUVmax in up to 16 matched lesions between the two scans. Patients were also divided by HER2 status (+/-). In addition, a subset of patients who underwent at least 2 paired FDG and FES scans were reviewed. Results: 270 matched FDG and FES scans were analyzed in 216 patients with history of ER+, and HER2+ or HER2- breast cancer who were not part of an ongoing clinical trial. 158 (73%) had ductal disease, 38 (18%) had lobular disease. 183 (85%) had HER2- breast cancer. Of the 33 patients who had HER2+ breast cancer, 28 (85%) had ductal carcinoma. 40 patients underwent serial scans, allowing tracking over multiple timepoints. A total of 1323 metastatic sites were recorded (average = 5/scan (range 1,16)), with the majority (71%) representing bony lesions. No difference in quantitative FES or FDG avidity was observed between soft tissue and osseous sites. FES and FDG SUVmax were similar among patients with either HER2- or HER2+ breast cancer (Table 1). Among 40 patients with multiple paired FDG and FES scans, 26 (65%) had 2 scans while the remaining 14 had 3, with FES avidity remaining stable over time. There was no correlation between FES or FDG scans and HER2 status. Conclusion: In a cohort of ER+, HER2+ and HER2- patients undergoing concurrent FDG and FES PET scans, FDG and FES activity was similar regardless of HER2 status. FES uptake in both HER2- and HER2+ patients and stability over time in serial scans suggest that HER2 does not affect ER density. This suggests that in many patients with so-called “triple positive” disease, endocrine therapy may offer a powerful primary rather than ancillary tool in select patients. FES combined with FDG PET may offer utility in predicting and assessing response to therapy in this patient population. Table 1. FES and FDG uptake in patients with HER2- or HER2+ disease Citation Format: Natasha Hunter, Lanell M. Peterson, David A. Mankoff, Mark Muzi, Delphine Chen, William R. Gwin, Shaveta Vinayak, Nancy E Davidson, Jennifer M. Specht, Hannah Linden. Fluoroestradiol (FES) and Fluorodeoxyglucose (FDG) PET imaging in patients with ER+, HER2+ or HER2- metastatic breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-03-17.

ACTH-Independent Cushing's Syndrome Caused by an Ectopic Adrenocortical Adenoma in the Renal Hilum.

We report a rare case of Cushing’s syndrome induced by an ectopic adrenocortical adenoma. A 57-year-old woman was diagnosed with adrenocorticotropic hormone (ACTH)-independent Cushing’s syndrome based on clinical manifestation and laboratory information. She was found to have a mass in the left renal hilum via contrast-enhanced computed tomography (CT). The mass was negative, as seen in somatostatin receptor imaging with 99mTc-hydrazinonicotinyl-Tyr3-octreotide (HYNIC-TOC), and showed mild fluorodeoxyglucose (FDG) activity via positron emission tomography (PET)/CT. The results of adrenal venous sampling suggested a left-side adrenal origin of hypercortisolism, possibly secreted by the mass in the renal hilum. Histopathology after surgical resection of the mass confirmed an ectopic adrenocortical adenoma, which was responsible for the patient’s Cushing’s syndrome. During the 8-month follow-up after surgery, no recurrence of Cushing’s syndrome was found.

Marked Hypoleptinemia precedes Overt Fat Loss in Immune Checkpoint Inhibitor-induced Acquired Generalized Lipodystrophy

<h3>Lead Author's Financial Disclosures</h3> Nothing to disclose. <h3>Study Funding</h3> None. <h3>Background/Synopsis</h3> The development of immune checkpoint inhibitors (ICIs) targeting cancer cells that evade immune T-cell regulation has revolutionized the treatment of metastatic carcinomas. Unfortunately, secondary endocrinopathies associated with ICI use, including adrenal insufficiency, primary hypothyroidism, autoimmune diabetes, and rarely hypoparathyroidism, are increasing. Lipodystrophy, presumably due to autoimmune destruction of adipocytes, leading to metabolic complications is a less well recognized adverse effect of ICI therapy. <h3>Objective/Purpose</h3> To report the clinical features and evolution of Acquired Generalized Lipodystrophy (AGL) in a patient on ICI therapy. <h3>Methods</h3> Case Report: A 66-year-old woman with metastatic lung adenocarcinoma was started on combination chemo/immunotherapy with programmed cell death-1 (PD-1) inhibitor- pembrolizumab after surgical resection of cerebellar mass and radiation. She had good tumor response but developed primary hypothyroidism and secondary adrenal insufficiency approximately ten months after initiation of ICI. <h3>Results</h3> Approximately 15 months following the treatment, she developed new-onset insulin requiring diabetes mellitus but without autoantibodies associated with type 1 diabetes. At that time, she was also noted to have hypertriglyceridemia (436 mg/dL), and elevated liver enzymes (3-4 X ULN), and a subsequent liver biopsy revealed severe macrovesicular steatosis. Her BMI was 30 kg/m2 and she had mild loss of buccal fat. Skin fold thickness measurements over the trunk and limbs were in the normal range. However, she had an undetectable serum leptin level and whole body fluorodeoxyglucose (FDG)- positron emission tomography (PET) scan, obtained for cancer surveillance, showed mild diffuse FDG activity throughout the subcutaneous tissues. She was advised low fat diet and started on insulin therapy. Over the next three months, she lost about 20 kg weight with generalized loss of subcutaneous fat from face, trunk, and extremities. Pioglitazone was started but discontinued after 4 weeks due to pedal edema and no effect on fat loss. Despite generalized lipodystrophy, she has maintained good glucose control on moderate dose insulin therapy (0.6 â€" 0.8 units/kg) and with normalization of liver enzymes and serum triglycerides. <h3>Conclusions</h3> ICI therapy can be associated with AGL, and the diagnosis must be considered in patients who develop metabolic complications such as diabetes, dyslipidemia, or steatohepatitis. Interestingly, metabolic abnormalities may precede overt fat loss. Hypoleptinemia and diffuse FDG uptake of subcutaneous tissue suggest subclinical panniculitis and adipocyte dysfunction even before clinically evident lipodystrophy.

A prospective trial of CT-guided percutaneous microwave ablation for lung tumors.

BackgroundPercutaneous ablation is an alternative treatment for lung cancer in non-operable patients. This is a prospective clinical trial for percutaneous microwave ablation (pMWA) of biopsy-proven lung cancer to demonstrate safety and efficacy.MethodsA prospective trial from 6-1-2016 to 1-1-2019 enrolled patients with biopsy-proven primary or metastatic lung cancer <3 cm in size and 1 cm away from the pleura for pMWA with the Emprint Ablation System with Thermosphere Technology for Phase I analysis, (Clinicaltrials.gov; #NCT0267302). Patients were followed for 1 year with PET/CT and PET/MR to determine patterns of recurrence and efficacy of ablation.ResultsAfter 12 patients consented for biopsy, 6 patients underwent treatment of 7 lesions, 3/6 women, median age of 67 (IQR, 65–70) years, body mass index (BMI): 27.8 (IQR, 21.4–32.1) kg/m2, lesion distance to pleura 24.4 (IQR, 13–38) mm, lesion size of 10.7 (IQR, 6–14) mm, and ablation duration time 5.9 (IQR, 3–10) minutes. pMWA were completed at 75 W. Twelve adverse events were reported (1 Grade 3, 3 Grade 2, and 8 Grade 1 events) with Grade 4 or 5 events. Mean % change after ablation in forced expiratory volume in one second (FEV1) was −2% and diffusion capacity for carbon monoxide (DLCO) was −1%. After 2–3 months, the lesions would decrease in size, rim thickness, fluorodeoxyglucose (FDG) activity, and T2 signal. FDG activity after 6 months was below blood pool in all cases. The ablation zones stabilized by 6–12 months. One patient expired during the study from pneumonia unrelated to ablation without local recurrence. Of the seven ablations during the 1 year follow-up, there was local tumor recurrence at 271 days following ablation at the apex of the ablation zone, subsequently successfully treated with percutaneous cryoablation (Cryo).ConclusionspMWA appears to be a safe and effective mechanism for treatment of primary and secondary tumors of the lung, with possible preservation of pulmonary function.

Biologically Active Volume of Disease (BaVD) Predicts for Survival in Metastatic Non-Small Cell Lung Cancer

Multiple randomized trials incorporating locally ablative therapy in oligometastatic non-small cell lung cancer (NSCLC) have used number of metastatic sites to identify which patient populations benefit from aggressive local therapy. In this study, we measure the amount of fluorodeoxyglucose (FDG) activity on positron emission tomography/computerized tomography (PET/CT) scans to quantify the biologically active volume of disease (BaVD) at diagnosis. We hypothesize that BaVD is a significant predictor of overall survival (OS) for NSCLC.We reviewed consecutive charts of metastatic NSCLC patients treated at our institution. All patients included had a PET/CT scan prior to starting any therapy. An oncology imaging informatics system was utilized to auto-contour individual PET/CT scans. A threshold SUV of 3 was selected a priori to auto-contour all FDG avid areas on each patient's pre-treatment PET/CT. SUV activity was measured in cubic centimeters (cc). Normal physiologic activity in expected organs including brain, heart, liver, spleen, genitourinary track, and gastrointestinal track was removed through auto-contouring and adjusted manually if needed. All plans were reviewed by a radiation oncologist to confirm FDG avid areas contoured only included areas of gross disease. Kaplan-Meier analysis evaluated overall survival (OS) based on volume of metastatic disease at diagnosis. Multivariate Cox regression (MVA) was performed accounting for age, histology, gender, race, smoking status, molecular mutations, presence of brain metastasis at diagnosis, number of metastatic sites (1-3, 4-5, > 5 sites), and type of systemic treatment received.A total of 43 patients were included. Median volume of disease using an SUV cutoff of ≥3 was 317 cc (range, 23-2476 cc). Median survival was worse for patients with ≥ 317 cc of disease compared to those < 317 cc, 17 mo vs 22 mo (P = 0.010). Volume of disease was found to be significant under univariate analysis (UVA) both when analyzed as a continuous (hazard ratio [HR] 1.01, 95% confidence interval [CI] 1.00-1.02, P < 0.001) and categorical variable with a cutoff of 317 cc (HR 3.27, 95% CI, 1.26-8.48, P = 0.013). On MVA, volume of disease remained a significant predictor of OS (HR 5.19, 95% CI 1.17-22.99, P = 0.030). Additional variables associated with OS included older age (HR 6.26, 95% CI 1.65-23.76, P = 0.007) and receipt of chemotherapy/immunotherapy (HR 20.51, 95% CI 1.98-212.09, P = 0.011) vs targeted therapy. While number of metastatic sites was significant under UVA (HR 8.45, 95% CI 1.10-64.72, P = 0.040), it was not significant under MVA (HR 5.23, 95% CI 0.56-49.91, P = 0.164) CONCLUSION: To our knowledge, this is one of the first studies to demonstrate the significance of BaVD as an important predictive factor of OS in metastatic NSCLC. Our results also suggest BaVD may be a stronger correlate to OS compared to number of metastatic sites. Further work is needed to better understand the impact BaVD on OS.

Hippocampal glucose uptake as a surrogate of metabolic change of microglia in Alzheimer\u2019s disease

BackgroundDynamically altered microglia play an important role in the progression of Alzheimer’s disease (AD). Here, we found a close association of the metabolic reconfiguration of microglia with increased hippocampal glucose uptake on [18F]fluorodeoxyglucose (FDG) PET.MethodsWe used an AD animal model, 5xFAD, to analyze hippocampal glucose metabolism using both animal FDG PET and ex vivo FDG uptake test. Cells of the hippocampus were isolated to perform single-cell RNA-sequencing (scRNA-seq). The molecular features of cells associated with glucose metabolism were analyzed at a single-cell level. In order to apply our findings to human brain imaging study, brain FDG PET data obtained from the Alzheimer’s Disease Neuroimaging Initiative were analyzed. FDG uptake in the hippocampus was compared according to the diagnosis, AD, mild cognitive impairment, and controls. The correlation analysis between hippocampal FDG uptake and soluble TREM2 in cerebrospinal fluid was performed.ResultsIn the animal study, 8- and 12-month-old 5xFAD mice showed higher FDG uptake in the hippocampus than wild-type mice. Cellular FDG uptake tests showed that FDG activity in hippocampal microglia was increased in the AD model, while FDG activity in non-microglial cells of the hippocampus was not different between the AD model and wild-type. scRNA-seq data showed that changes in glucose metabolism signatures including glucose transporters, glycolysis and oxidative phosphorylation, mainly occurred in microglia. A subset of microglia with higher glucose transporters with defective glycolysis and oxidative phosphorylation was increased according to disease progression. In the human imaging study, we found a positive association between soluble TREM2 and hippocampal FDG uptake. FDG uptake in the hippocampus at the baseline scan predicted mild cognitive impairment conversion to AD.ConclusionsWe identified the reconfiguration of microglial glucose metabolism in the hippocampus of AD, which could be evaluated by FDG PET as a feasible surrogate imaging biomarker for microglia-mediated inflammation.

Feasibility of equivalent performance of 3D TOF [18F]-FDG PET/CT with reduced acquisition time using clinical and semiquantitative parameters

BackgroundHigh-performance time-of-flight (TOF) positron emission tomography (PET) systems have the capability for rapid data acquisition while preserving diagnostic image quality. However, determining a reliable and clinically applicable cut-off of the acquisition time plays an important role in routine practice. This study aimed to assess the diagnostic equivalence of short acquisition time of 57 with routine 75 seconds per bed position (s/BP) of [18F]-fluoro-deoxy-glucose (FDG) PET.Phantom studies applying EARL criteria suggested the feasibility of shortened acquisition time in routine clinical imaging by 3D TOF PET/CT scanners. Ninety-six patients with melanoma, lung or head and neck cancer underwent a standard whole-body, skull base-to-thigh or vertex-to-thigh [18F]-FDG PET/CT examination using the 3D TOF Ingenuity TF PET/CT system (Philips, Cleveland, OH). The [18F]-FDG activity applied was equal to 4MBq per kg body weight. Retrospectively, PET list-mode data were used to calculate a second PET study per patient with a reduced acquisition time of 57 s instead of routine 75 s/BP. PET/CT data were reconstructed using a 3D OSEM TOF algorithm. Blinded patient data were analysed by two nuclear medicine physicians. The number of [18F]-FDG-avid lesions per body region (head&neck, thorax, abdomen, bone, extremity) and image quality (grade 1–5) were evaluated. Semiquantitative analyses were performed by standardized uptake value (SUV) measurements using 3D volume of interests (VOI). The visual and semiquantitative diagnostic equivalence of 214 [18F]-FDG-avid lesions were analysed in the routine standard (75 s/BP) as well as the calculated PET/CT studies with short acquisition time. Statistical analyses were performed by equivalence testing and Bland–Altman plots.ResultsLesion detection rate per patient’s body region agreed in > 98% comparing 57 s/BP and 75 s/BP datasets. Overall image quality was determined as equal or superior to 75 s in 80% and 69%, respectively. In the semiquantitative lesion-based analyses, a significant equivalence was found between the 75 s/BP and 57 s/BP PET/CT images both for SUVmax (p = 0.004) and SUVmean (p = 0.003).ConclusionThe results of this study demonstrate significant clinical and semiquantitative equivalence between short acquisition time of 57 s/BP and standard 75 s/BP 3D TOF [18F]-FDG PET/CT scanning, which may improve the patient’s workflow in routine practice.

PNEUMONIA OR LYMPHOMA? DO NOT BE FOOLED!

SESSION TITLE: Medical Student/Resident Lung Pathology SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Mucosa-associated lymphoid tissue (MALT) Lymphoma, also known as Extranodal Marginal Zone B cell lymphoma (EMZL), is a rare type of non-Hodgkin’s lymphoma with an incidence rate of 18.3 cases per 1 million in the United States. The objective of this case is to describe a challenging case of EMZL presenting as persistent localized lung consolidation that was mistaken for pneumonia. CASE PRESENTATION: 77-year-old male, former smoker who presented with complains of nonproductive cough for several weeks, chest-x-ray (CXR) showed a 4.3 cm rounded hazy right parahilar mass. A follow up computed tomography (CT) of the chest revealed 4.7 x2.8 cm consolidative opacity along the interlobar fissure in the right upper lobe (RUL). Reviewing back a year ago, CT scan done for nonspecific chest pain, showed the mass size was unchanged but appeared to be less solid compared to the current scan. Patient underwent a Fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan which showed elevated FDG activity SUV 3.0 associated with a consolidative pulmonary opacity in the posterior portion of the right upper lobe silhouetting the major fissure. The patient subsequently underwent a CT guided percutaneous biopsy of the right upper lobe airspace consolidation. Histologic sections showed interstitial expansion and bronchial epithelium involvement by small monocytoid- appearing lymphocytes and significant amount of plasma cells (Figure 1). Immunohistochemistry was positive for CD20 and BCL-2 and negative for BCL-6 and CD10. CD138 which highlights plasma cell component was positive. Immunostaining for kappa and lambda showed findings most suggestive of monotypic lambda expression. Fluorescence in situ hybridization (FISH) studies for MALT1 (18q21) rearrangement identified a MALT1 gene rearrangement and B cell clonality studies done by PCR were positive for a clonal rearrangement. Therefore, the final diagnosis was small B-cell non-hodgkin lymphoma consistent with extranodal MALT. In retrospect the lymphoma was likely present a year ago however mistaken as a pneumonia. Given the lack of symptoms and minimal progression of over one year, was consistent with the indolent clinical behavior of the tumor. Decision was made not to treat at this point by the physician and patient. Till date patient remain asymptomatic. DISCUSSION: EMZL has been associated with persistent inflammatory state, either infectious or autoimmune in nature. EMZL can present in various ways from an incidental finding on imaging to ambiguous symptoms such as dyspnea, chest pain, cough, and rarely hemoptysis. Prognosis in MALT-type lymphomas is generally good with mean survival of more than 10 years. CONCLUSIONS: In conclusion, EMZL of the lung is uncommon and unique therefore a collaborative effort addressing early diagnosis and less invasive diagnostic testing for these high-risk EMZL patients are needed. Reference #1: Khalil MO, Morton LM, Devesa SS, et al. Incidence of marginal zone lymphoma in the United States, 2001 to 2009 with a focus on primary anatomic stie. Br J Haematol 2014; 165:67 Reference #2: Santos IG, Marchiori E, Zanetti G, Mano CM, SarcielliLuz B, Vianna FG. Primary pulmonary mucosaasociated lymphoid tissue lymphoma computed tomography findings: A case report. Cases J. 2009;2:6329. [PMCID:PMC2740136] [PubMed: 19829788] DISCLOSURES: No relevant relationships by Hussein Hussein, source=Web Response No relevant relationships by Ahmad JABRI, source=Web Response No relevant relationships by Sonya Joshi, source=Web Response No relevant relationships by Sujith Modugula, source=Web Response No relevant relationships by Elizabeth Verghese, source=Web Response

18F-FDG uptake in the normal appendix in adults: PET/CT evaluation.

This study aimed to determine the level of 18F fluorodeoxyglucose (18F-FDG) activity in the normal adult appendix using positron emission tomography/computed tomography (PET/CT). We performed a retrospective review of PET/CT images using 18F-FDG in 563 consecutive asymptomatic adult patients without appendiceal pathology. We excluded 257 patients for an undetected or obscured appendix and three patients for appendicitis found on CT imaging. FDG uptake in the appendix was qualitatively and quantitatively assessed. The maximum standardized uptake value (SUVmax) was calculated for quantitative analysis with SUVmax of the normal liver for comparison. A total of 303 patients (200 males, 103 females, mean age of 66years) were included in this study. Medical charts and histories were evaluated for patients who showed positive FDG accumulation. Pearson's correlations between appendiceal SUVmax and age, body mass index, and blood glucose levels were analyzed. The mean appendiceal SUVmax was 1.14 (range 0.52-5.12) with an appendix-to-liver SUVmax ratio of 0.34 (range 0.06-1.28). Three patients qualitatively showed a positive FDG accumulation with appendiceal SUVmax greater than 3.00. There were no correlations between appendiceal SUVmax and age, body mass index, or blood glucose levels. FDG in the normal adult appendix shows a low activity level and is lower compared with normal liver. However, the normal appendix can rarely show high FDG accumulation. In such cases, differentiation from appendiceal pathology solely by PET/CT images would be difficult.

MP14-02 ROLE OF [18F] FLUORODEOXYGLUCOSE-PET IN DIFFERENTIATING PAPILLARY RENAL CELL CARCINOMA FROM CLEAR CELL RENAL CELL CARCINOMA AND ONCOCYTOMA

You have accessJournal of UrologyImaging/Radiology: Uroradiology I1 Apr 2018MP14-02 ROLE OF [18F] FLUORODEOXYGLUCOSE-PET IN DIFFERENTIATING PAPILLARY RENAL CELL CARCINOMA FROM CLEAR CELL RENAL CELL CARCINOMA AND ONCOCYTOMA Moozhan Nikpanah, Mark A. Ahlman, A. Cahid Civelek, S. Mojdeh Mirmomen, Xiaobai Li, Anna K. Paschall, Ramaprasad Srinivasan, Faraz Farhadi, W. Marston Linehan, and Ashkan A. Malayeri Moozhan NikpanahMoozhan Nikpanah More articles by this author , Mark A. AhlmanMark A. Ahlman More articles by this author , A. Cahid CivelekA. Cahid Civelek More articles by this author , S. Mojdeh MirmomenS. Mojdeh Mirmomen More articles by this author , Xiaobai LiXiaobai Li More articles by this author , Anna K. PaschallAnna K. Paschall More articles by this author , Ramaprasad SrinivasanRamaprasad Srinivasan More articles by this author , Faraz FarhadiFaraz Farhadi More articles by this author , W. Marston LinehanW. Marston Linehan More articles by this author , and Ashkan A. MalayeriAshkan A. Malayeri More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.495AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES We assessed differences in [18F] fluorodeoxyglucose (FDG) PET-derived standardized uptake value (SUV) of renal neoplasms, including papillary renal cell carcinoma (pRCC) type 1 and 2, clear cell renal cell carcinoma (ccRCC) and oncocytoma. METHODS In this retrospective study, 100 pathology proven renal lesions (25 pRCC type 1, 8 pRCC type 2, 57 ccRCC, 10 oncocytoma) that met our inclusion criteria (size ≥1cm, timeframe between the preoperative FDG PET/CT performed and surgery ≤18 months) were selected from 35 patients. Renal lesions with distant metastasis were identified. Two nuclear medicine specialists, blinded to clinical information, independently reviewed FDG-PET/CT images. With care to avoid urinary FDG activity, lesional SUV mean was determined and target to background ratio respective to liver (TBRLiver) was calculated. Intrarater reliability score was calculated by using unweighted k statistics to measure agreement between the readers. Values were averaged to a single measurement for each lesion. Linear mixed model was used to compare TBRLiver values among four categories of neoplasm. The model accounted for within-patient correlation and metastatic or non-metastatic designation of the lesions. RESULTS The 100 renal lesions were selected from 35 patients (24 male and 11 female, mean age: 54). Metastatic lesions included 9 pRCC type 1, 4 pRCC type 2, and 11 ccRCC. Intrarater reliability test resulted in a mean k score of 0.86. Median TBRLiver value (interquartile range) was 1.23 (0.53, 5.04) for pRCC type 1, 3.78 (0.49, 8.46) for pRCC type 2, 0.94 (0.41,2.21) for ccRCC, and 0.99 (0.63,1.41) for oncocytoma. The mixed model showed a significant difference in TBRLiver value among four categories (p=0.0003). Pairwise comparison showed significant difference in TBRLiver value between ccRCC and pRCC type 2 (p<0.0001), pRCC type 1 and pRCC type 2 (p=0.01), and oncocytoma and pRCC type 2 (p=0.025). CONCLUSIONS Papillary type 2 of renal cell carcinoma has higher FDG activity than clear cell RCC, papillary type 1 RCC, and oncocytoma. These findings are important to help determine if an imaging biomarker such as FDG is useful to study the genetic-metabolic linkages and clinical applicability in renal neoplasms. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e179-e180 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Moozhan Nikpanah More articles by this author Mark A. Ahlman More articles by this author A. Cahid Civelek More articles by this author S. Mojdeh Mirmomen More articles by this author Xiaobai Li More articles by this author Anna K. Paschall More articles by this author Ramaprasad Srinivasan More articles by this author Faraz Farhadi More articles by this author W. Marston Linehan More articles by this author Ashkan A. Malayeri More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Invited commentary

Microinhibitory RNA (miRNA) were first described by Ambrose et al1Lee R.C. Feinbaum R.L. Ambros V. The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14.Cell. 1993; 75: 843-854Abstract Full Text PDF PubMed Scopus (9619) Google Scholar in 1993. They represented an entirely new and important layer of gene regulation. They are naturally occurring short, single-stranded RNA sequences that typically regulate many different genes. It is interesting to note that Andy Fire and Craig Mello received the 2006 Nobel Prize for Medicine for the use of synthetic double-stranded RNA that could inhibit protein production (small-interfering RNA).2Fire A. Xu S. Montgomery M.K. Kostas S.A. Driver S.E. Mello C.C. Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans.Nature. 1998; 391: 806-811Crossref PubMed Scopus (11712) Google Scholar The discovery of Victor Ambrose is arguably of equal importance. Elegant studies have since demonstrated their role in regulating abdominal aortic aneurysm (AAA).3Maegdefessel L. Azuma J. Toh R. Deng A. Merk D.R. Raiesdana A. et al.MicroRNA-21 blocks abdominal aortic aneurysm development and nicotine-augmented expansion.Sci Transl Med. 2012; 4: 122ra22Crossref PubMed Scopus (227) Google Scholar The work presented by Courtois et al takes these findings to another level. By comparing patients whose AAAs showed activity on positron emission tomography (PET) scan against a group of PET-negative AAA patients, the authors have identified a small number of circulating miRNAs that can effectively distinguish between the groups. Finding an accurate systemic biomarker for the presence of AAA or for AAA that are likely to progress to rupture would be an important advance in public health. The study by Courtois et al does not address the issue of identifying a biomarker to find those with AAA. This remains a critical question, because too many patients at risk are not being screened despite the efforts of the Society for Vascular Surgery in promoting aneurysm screening.4Mell M.W. Hlatky M.A. Shreibati J.B. Dalman R.L. Baker L.C. Late diagnosis of abdominal aortic aneurysms substantiates underutilization of abdominal aortic aneurysm screening for medicare beneficiaries.J Vasc Surg. 2013; 57 (1523.e1): 1519-1523Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar Significant progress in understanding AAA biology has been made in recent decades. We understand that inflammation drives the pathophysiology. An entirely logical assumption, therefore, is that circulating markers that reflect PET fluorodeoxyglucose activity would identify aneurysms most likely to progress, possibly to rupture. Although the results presented in their study are exciting, we should not get ahead of ourselves as clinicians and scientists. Studying AAA rupture is extremely difficult because small aneurysm rupture is rare, and patients at risk of rupture, based on size, are repaired. Although logical to assume a link between increased PET fluorodeoxyglucose activity and risk of rupture, the data are not there to make this jump. Important questions remain, including whether an aneurysm might show increased activity at one point with regression of the inflammation over time. So how might biomarkers that identify more dangerous AAA be found? The most convincing data would be derived from a carefully studied cohort where aneurysm progression is tracked longitudinally by the best available imaging (computed tomography or magnetic resonance imaging). Showing biomarkers that strongly correlate with growth or, conversely, lack of growth over time would provide the best support for clinical application. The carefully conducted studies by Courtois et al suggest that a panel of miRNAs could prove to be a very useful biomarker in the future for tracking AAA progression. The opinions or views expressed in this commentary are those of the authors and do not necessarily reflect the opinions or recommendations of the Journal of Vascular Surgery or the Society for Vascular Surgery. Circulating microRNAs signature correlates with positive [18F]fluorodeoxyglucose-positron emission tomography in patients with abdominal aortic aneurysmJournal of Vascular SurgeryVol. 67Issue 2PreviewPrediction of abdominal aortic aneurysm (AAA) rupture is a challenging issue. Small noncoding microRNAs (miRNAs) are potent regulators of gene expression and are considered as valuable circulating biomarkers. Recently, [18F]fluorodeoxyglucose (FDG) uptake detected by positron emission tomography (PET) in AAA was correlated with cellular and molecular alterations involved in wall instability and its potential rupture. Our study aimed at identifying circulating miRNAs correlated with a positive PET that could help discriminate patients at high risk of rupture. Full-Text PDF Open Archive

Fluorodeoxyglucose activity associated with a cosmetic poly-L-lactide filler: a potential confounder on positron emission tomography and computed tomography

Injectable cosmetic fillers are increasingly popular, but are not often considered as a cause of abnormal findings on imaging. We present a case of poly-L-lactic acid (PLLA) filler associated with 18-fluorodeoxyglucose (FDG) uptake, which had the potential to interfere with staging of a squamous cell carcinoma of the lateral tongue. We characterise the FDG-positron emission tomography/computed tomography (PET/CT) properties of a PLLA dermal filler, Sculptra® (Aventis), and highlight its potentially confounding appearance in the staging scans of oncological patients, particularly those with oral tumours.

Cardiovascular Immunotherapy and the Role of Imaging.

Despite significant advances in prevention and treatment, cardiovascular diseases (CVDs) remain the most common cause of death in the United States.1–3 In part, and compared with treatment developments in oncology, this is because of the lack of current generation CVD precision therapies.4–6 Most CVDs are caused by atherosclerosis, a disease process that causes thickening of the arterial wall because of inflammation and lipid accumulation, resulting in plaque formation.7,8 Macrophage dynamics plays a central role in atherosclerosis progression, vessel wall destabilization, and—as has been recently discovered—plaque aggravation because of myocardial infarction.9–11 Therefore, and despite current standardized treatments, ≈25% of patients who had myocardial infarction or stroke will experience secondary major adverse cardiovascular events, often more harmful than the primary event.12–14 To break this vicious cycle, innovative and tailored therapeutic strategies are needed. Various targeted immunotherapies that showed anticancer potential in in vitro screens also displayed in vivo potential in mouse models. Such proof-of-concept studies in validated syngeneic mouse tumor models not only provide information on in vivo efficacy but also disclose the targeted immunotherapies’ underlying mechanism of action and safety profile. However, immunotherapies’ high costs and the identification of amendable patients compromise clinical translation.15,16 Continued and focused efforts are needed to understand patient responsiveness and reduce high dropout rates in trials. A parallel effort focused on the development of novel imaging tools that can guide patient selection may offer a potential solution. Positron emission tomography (PET) can be used to trace immunotherapies. So-called immunoPET uses antibodies, developed for cancer treatment, that selectively recognize a specific epitope on target cells. The antibodies are labeled with radioactive isotopes, such as zirconium-89 or iodine-124, with relatively long decay half-lives of 3.27 and 4.18 days, respectively, to …

Changes in [18F]Fluorodeoxyglucose Activities in a Shockwave-Induced Traumatic Brain Injury Model Using Lithotripsy.

We present a longitudinal study of cerebral metabolism using [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in a rat model of shockwave-induced traumatic brain injury (SW-TBI). Anesthetized rats received 5 or 10 SW pulses to the right anterior lateral or dorsal frontal regions using SW lithotripsy. Animals were scanned for FDG uptake at baseline, 3 h post-injury, and 3 days post-injury, using a small animal PET/computed tomography (CT) scanner. FDG uptake at all time-points was quantified as the ratio of brain activity relative to peripheral activity in the left ventricle (LV) in the heart (Abrain/ALV) for the entire brain, each hemisphere, and four cortices (motor, cingulate, somatosensory, and retrosplenial). The mixed-designed models analysis of variance (ANOVA) for the hemispheric and global FDG uptake ratio showed a significant effect of the time-of-scan (p = 0.038) and measured region (p = 6.12e-09). We also observed a significant effect of the time-of-scan (p = 0.046) and measured region (p = 2.28e-09) for the FDG uptake ratio in four cortical regions. None of the measurements (global or local) showed a significant effect for the number of SW pulses (5 or 10) or SW location (lateral or dorsal frontal regions). Our data suggest that SW-TBI causes hypermetabolism on the impact side of the rat brain at 3 h post-injury compared with the baseline measurements. However, the increase in FDG uptake by day 3 post-injury was not significant. Further studies on post-TBI metabolic changes are needed to understand better the pathophysiology of the injury.

Multicenter clinical and imaging evaluation of targeted radiofrequency ablation (t-RFA) and cement augmentation of neoplastic vertebral lesions

BackgroundTreatment of spinal metastatic lesions by radiofrequency ablation (RFA) before cementation can potentially help in local tumor control and pain relief. This is often limited by access and tumor location....

FDG PET/CT Pitfalls in Gynecologic and Genitourinary Oncologic Imaging.

The role of whole-body positron emission tomography (PET)/computed tomography (CT) with fluorodeoxyglucose ( FDG fluorodeoxyglucose ) is now established in the assessment of many gynecologic and genitourinary malignant tumors. FDG fluorodeoxyglucose PET/CT has been widely adopted for staging assessments in patients with suspected advanced disease, in cases of suspected disease recurrence, and for determining prognosis in a number of malignancies. A number of pitfalls are commonly encountered when reviewing FDG fluorodeoxyglucose PET/CT scans in gynecologic and genitourinary cases; these pitfalls can be classified into those that yield potential false-positive or false-negative results. Potential false positives include physiologic uptake of FDG fluorodeoxyglucose by the endometrium and ovaries in premenopausal patients, physiologic renal excretion of FDG fluorodeoxyglucose into the ureters and the urinary bladder, and increased FDG fluorodeoxyglucose activity in benign conditions such as uterine fibroids, pelvic inflammatory disease, and benign endometriotic cysts. Potential false negatives include low-level FDG fluorodeoxyglucose uptake by necrotic, mucinous, cystic, or low-grade tumors and the masking of serosal and peritoneal disease by adjacent physiologic bowel or bladder activity. In addition, there are inherent technical limitations-such as motion artifact (from respiratory motion and bowel peristalsis) and the limited spatial resolution of PET-that may limit the assessment of small-volume malignant disease. Knowledge of the key imaging features of physiologic and nonphysiologic FDG fluorodeoxyglucose uptake, in addition to understanding the principles of adequate patient preparation and PET scanning protocols, is important for accurate interpretation of gynecologic and genitourinary oncologic FDG fluorodeoxyglucose PET/CT studies. ©RSNA, 2017.