Body PET Research Articles

P382 TEAMWORK IS SUCCESSFUL (2): PATIENT WITH DIFFUSE LARGE B–CELL LYMPHOMA (DLBCL) AND MULTIPLE HEART MASSES

Abstract Introduction Patients (Pts) with lymphoma are at high risk of cardiovascular events for the cardiotoxic effects of therapies and direct involvement of the heart. Autopsy series, indeed, indicate that cardiac localization may be observed in 10 – 25% of DLBCL Pts. The presence of cardiac mass, in DLBCL poses further complexity to the management beyond myocardial chemotherapy–related cardiotoxicity for the possible unfavorable/unpredictable evolution of the lymphoma mass (arrhythmias, AV block, myocardial ischemia, pericardial effusion and cardiac tamponade). We report the case of pt. with diffuse DLBCL, and multiple cardiac locations discovered, incidentally, on total body PET performed for disease stratification. Clinical case A 72–year–old woman with worsening asthenia and advanced stage non–GCB DLBCL presented multiple cardiac radiotracer uptake at 18FDG PET. The basal echocardiogram evidenced a roundish pedunculated mass at the level of the outflow tract of the right ventricle (24 x 22 mm) with significant obstruction of the RVOT, an oval formation at right ventricular apex with possible myocardial infiltration and a further mass in the right atrial site. Mild (< 1 mm) circumferential pericardial effusion, finally, was appreciated. No other notable alterations . After multi–disciplinary discussion, the patient underwent R–COMP based induction regimen, thus substituting conventional doxorubicin (R–CHOP) with non–pegylated liposomal doxorubicin in order to reduce the risk of acute cardiotoxicity. The first cycle was administered as inpatient under close cardiac monitoring, that was subsequently carried on before each cycle. No embolic and/or mechanical complications occurred. The response to chemotherapy was excellent: after the first cycle a substantial reduction in size of the cardiac masses was observed and after 3 cycles a complete resolution of the same was observed. Interim response evaluation by 18FDG PET after cycle 3 upheld early ultrasound observations by displaying a complete disappearance of pathological uptake. Conclusions In the case of patients with advanced DLBCL, multi–imaging evaluation enable appropriate assessment of cardiac conditions, including possible cardiac location and nature of masses. The personalized multidisciplinary management allows a tailored management of complex cases that enables both the achievement of treatment goals and the avoidance of acute complications.

The role of imaging and sentinel lymph node biopsy in patients with T3b-T4b melanoma with clinically negative disease.

Previous studies demonstrate minimal utility of pre-operative imaging for low-risk melanoma; however, imaging may be more critical for patients with high-risk disease. Our study evaluates the impact of peri-operative cross-sectional imaging in patients with T3b-T4b melanoma. Patients with T3b-T4b melanoma who underwent wide local excision were identified from a single institution (1/1/2005 - 12/31/2020). Cross-sectional imaging was defined as body CT, PET and/or MRI in the perioperative period, with the following findings: in-transit or nodal disease, metastatic disease, incidental cancer, or other. Propensity scores were created for the odds of undergoing pre-operative imaging. Recurrence free survival was analyzed using the Kaplan-Meier method and log-rank test. A total of 209 patients were identified with a median age of 65 (IQR 54-76), of which the majority were male (65.1%), with nodular melanoma (39.7%) and T4b disease (47.9%). Overall, 55.0% underwent pre-operative imaging. There were no differences in imaging findings between the pre- and post-operative cohorts. After propensity-score matching, there was no difference in recurrence free survival. Sentinel node biopsy was performed in 77.5% patients, with 47.5% resulting in a positive result. Pre-operative cross-sectional imaging does not impact the management of patients with high-risk melanoma. Careful consideration of imaging use is critical in the management of these patients and highlights the importance of sentinel node biopsy for stratification and decision making.

Deep Learning Denoising Improves and Homogenizes Patient [18F]FDG PET Image Quality in Digital PET/CT.

Given the constant pressure to increase patient throughput while respecting radiation protection, global body PET image quality (IQ) is not satisfactory in all patients. We first studied the association between IQ and other variables, in particular body habitus, on a digital PET/CT. Second, to improve and homogenize IQ, we evaluated a deep learning PET denoising solution (Subtle PETTM) using convolutional neural networks. We analysed retrospectively in 113 patients visual IQ (by a 5-point Likert score in two readers) and semi-quantitative IQ (by the coefficient of variation in the liver, CVliv) as well as lesion detection and quantification in native and denoised PET. In native PET, visual and semi-quantitative IQ were lower in patients with larger body habitus (p < 0.0001 for both) and in men vs. women (p ≤ 0.03 for CVliv). After PET denoising, visual IQ scores increased and became more homogeneous between patients (4.8 ± 0.3 in denoised vs. 3.6 ± 0.6 in native PET; p < 0.0001). CVliv were lower in denoised PET than in native PET, 6.9 ± 0.9% vs. 12.2 ± 1.6%; p < 0.0001. The slope calculated by linear regression of CVliv according to weight was significantly lower in denoised than in native PET (p = 0.0002), demonstrating more uniform CVliv. Lesion concordance rate between both PET series was 369/371 (99.5%), with two lesions exclusively detected in native PET. SUVmax and SUVpeak of up to the five most intense native PET lesions per patient were lower in denoised PET (p < 0.001), with an average relative bias of -7.7% and -2.8%, respectively. DL-based PET denoising by Subtle PETTM allowed [18F]FDG PET global image quality to be improved and homogenized, while maintaining satisfactory lesion detection and quantification. DL-based denoising may render body habitus adaptive PET protocols unnecessary, and pave the way for the improvement and homogenization of PET modalities.

Automated production of [11C]butyrate for keto body PET imaging

The report describes an updated, fully automated method for the production of [11C]butyrate, validated for use in clinical studies. A commercially available GE Tracerlab FXM synthesis module was reconfigured to allow for air-free introduction of n-propyl magnesium chloride and to incorporate Sep-Pak cartridges to simplify and shorten the purification process, as compared to purifying the product using traditional HPLC. The method takes 20 min from end-of-bombardment and reliably produces injectable doses of [11C]butyrate (8029 ± 1628 MBq (217 ± 44 mCi), 14 % radiochemical yield based on [11C]CO2, non-decay corrected) in high radiochemical purity (>97 %), n = 3. With radiotracer in hand, PET scans of rats confirmed uptake of the radiopharmaceutical in the brain. Rat biodistribution data was obtained and used in conjunction with OLINDA software to determine an estimated human total body effective dose of 3.20 × 10−3 mSv/MBq (1.19 × 10−2 rem/mCi), along with preliminary rodent PET imaging that confirmed brain uptake. Lastly, our first human [11C]butyrate PET studies using a dynamic bolus injection technique (n = 5), with a graphical Logan analysis using a white matter reference region, confirmed good radiotracer uptake in the brain and with relatively more prominent uptake in the cerebellar hemispheres, vermis, cingulum cortex and the thalami.

1994. The use of whole body PET scans in management of infective endocarditis

Abstract Background Whole-body 18F-FDG PET/CT (WBP) can have diagnostic utility in evaluating extracardiac sites of metastatic infection in patients with infective endocarditis (IE). However, the IE patient population that most benefits from this test is not certain. The purpose of this study is to investigate the clinical characteristics of patients with IE who had WBP performed and to evaluate how WBP results impacted management. Methods We performed a retrospective cohort study at a tertiary care center evaluating patients with suspected IE who were discussed at an internal multidisciplinary endocarditis conference between June 2018 and January 2022. Adult patients with suspected IE who also had a WBP during their inpatient stay were included. Patient demographics, IE risk factors, and WBP details were collected. Results 114 patients with suspected IE had a WBP out of 431 (26.5%). The majority (n=107, 93.9%) had definite or possible IE by mDuke criteria. Prosthetic valves and endocardial devices were present in 83 (72.8%) and 34 (29.8%) patients respectively. There were 67 (60.5%) patients with 2 or more days of bacteremia and 21 (22.1%) patients with over 7 days of bacteremia. Causative pathogens included S. aureus (n=26, 24.2%), Enterococcus (n=26, 24.2%), and Streptococcus species (n=24, 22.4%). Among the 70 (61.4%) patients with indications for cardiac surgery, 38 (54%) had cardiac surgery performed. Common WBP findings were bone/joint infections (n=18, 15.8%), pulmonary infection (n=32, 28.1%), and skin/soft tissue infection (n=15, 13.2%). WBP changed the management in 44.7% (n=51) of patients, including antibiotic change (n=11, 9.7%), source control procedure (n=12, 10.5%), and further workup of infectious or non-infectious findings (n=33, 29.0%). Six-month all-cause mortality was 25% and hospital readmission was 48.1%. Conclusion Many patients who underwent WBP had prolonged bacteremia, a history of cardiac prostheses, and had complicated IE with indications for cardiac surgery. WBP results changed treatment in some cases, but true clinical impact on morbidity and mortality is uncertain. We plan to do further research to compare outcomes between patients who get WBP and those who do not and to determine which patients may most benefit from this test. Disclosures All Authors: No reported disclosures.

Glial Fibrillary Acidic Protein (GFAP) Antibody-Associated Astrocytopathy in Systemic Sarcoidosis

Objective To report two cases of glial fibrillary acidic protein (GFAP) antibody-associated meningoencephalitis in patients with biopsy-proven systemic sarcoidosis. Background GFAP astrocytopathy is an autoimmune neurologic disease first defined in 2016. To our knowledge, no association with systemic sarcoidosis has been previously reported. Design/Methods Case Series Results Patient 1 is a 47-year-old woman with pre-existing pulmonary sarcoidosis treated with steroids and methotrexate with remission 6 years prior. She subsequently developed new-onset epilepsy, progressive ataxia and vertical diplopia. GFAP antibodies were positive in the cerebrospinal fluid (CSF) by cell-based assay (CBA). Body PET scan showed diffuse FDG avidity in her lungs, spleen, and lymph nodes, suggesting simultaneous reactivation of her systemic sarcoidosis. She was treated with steroids followed by infliximab with resolution of her symptoms. Patient 2 is a 58-year-old man with known pulmonary sarcoidosis, who was off immunosuppression at the time of his presentation but had received steroids 17 years prior. He presented with progressive apathy, memory disturbance, dysarthria, and gait instability. MRI revealed widespread T2 hyperintensities. GFAP antibodies were positive in CSF on CBA and confirmed by tissue-based immunofluorescence assay. He received steroids with initial response but relapsed after steroid discontinuation. He improved after restarting steroids and was subsequently transitioned to infliximab with sustained neurologic recovery. Conclusions Sarcoidosis is a poorly understood multi-system disorder that is presumably an immune-mediated response to yet unidentified antigen(s). It is known to co-exist with other autoimmune diseases, with autoimmune thyroiditis being most common. GFAP astrocytopathy is also poorly understood. GFAP is found intracellularly and similar to other antibody-mediated diseases against intracellular epitopes, the antibodies are believed to be a biomarker of underlying autoimmunity but not directly pathogenic. We report these cases to highlight a potential association between production of intrathecal GFAP antibodies and systemic sarcoidosis, which may provide insights into the pathogenesis of these two diseases.

Co-Occurrence of Sj/ITPR1 and NMDA Antibodies: A Case Report

Objective To highlight a case of concurrent anti-SJ/ITPR1 and anti-NMDA encephalitis. Background The anti-Sj/inositol 1,4,5-trisphosphate receptor (ITPR1) has been associated with autoimmune cerebellar ataxia and malignancy. Reports of patients with anti-Sj/ITPR1 describe isolated cerebellar ataxia as well as various manifestations throughout the central and peripheral nervous system. Anti-NMDA encephalitis presents with subacute decline, seizures, movement disorder, alterations in behavior and cognition, autonomic dysfunction, and central hypoventilation but is rarely associated with cerebellar ataxia in adults. Design/Methods NA. Results A 28-year-old female with no relevant medical history presented to an outside hospital with acute onset headache, diplopia, nystagmus, and vertigo. MRI and MRV were unremarkable. CSF analysis showed a lymphocytic pleocytosis. She was empirically treated with acyclovir, although viral serologies were negative. On initial assessment in our clinic, neurologic exam showed square wave jerks, ataxic eye movements, resting tremor, appendicular and gait ataxia. She progressively declined with gait instability, autonomic dysfunction, neuropsychiatric symptoms, and significant weight gain from compulsive hyperphagia. Her course was complicated by respiratory failure and tracheostomy was placed for mechanical ventilation. Malignancy screening with mammogram, CT, and full body PET was negative. Transvaginal ultrasound was nondiagnostic. Serum paraneoplastic autoantibody panel was negative. EEG showed severe generalized slowing. Repeat CSF studies were positive for anti-SJ/ITPR1 and anti-NMDA. She was treated with high-dose IV methylprednisolone, plasmapheresis, and rituximab. She has residual moderate/severe ataxia, but is now conversant, without trach dependence, and ambulates with assistance. Conclusions There is no definite current evidence for the pathogenicity of the ITPR1 antibody. Given the rarity of cerebellar ataxia in anti-NMDA encephalitis in adults, one could argue for a pathogenic role of ITPR1 in our case. No underlying malignancy was identified in our patient. We will continue surveillance since the clinical syndrome may precede tumor identification by several years.

Abstract 10249: Infective Endocarditis: A Diagnostic Challenge

Case: A healthy 30-year-old female with past medical history of eczema and no prior cardiac history presented with altered mental status, fever, neck stiffness and photophobia. Blood and CSF cultures grew methicillin susceptible Staphylococcus aureus , and the patient was started on nafcillin and linezolid. Bacteremia source was unclear, presumed to be minor skin breaks on her hands. MRI brain revealed multiple cerebral septic emboli, prompting concern for infective endocarditis. However, TTE and TEE were negative for vegetations, valve thickening, and valvular regurgitation. Blood cultures remained positive for MSSA despite dual antibiotic therapy and by hospital day 4, she began experiencing shortness of breath and new Janeway lesions were noted on exam. Repeat TTE and TEE were also negative for endocarditis. To further evaluate for an arterial source of seeding, CTA chest/abdomen was obtained which was unremarkable. Given persistence of bacteremia despite dual antibiotic therapy and unknown left-sided source, whole body PET CT scan was obtained which showed focal FDG uptake in the mitral annulus/valve region. Repeat TEE the following day showed a mitral valve ring abscess, a 1.2x0.4cm vegetation involving the P3 segment of the mitral valve, perforation at the mitral valve annulus, and new moderate mitral regurgitation. After a risk benefit discussion, the patient opted for conservative management with serial monitoring over surgical repair. She was treated with six weeks of nafcillin and four weeks of linezolid. Most recent TEE showed resolution of valvular abscess and vegetation with continued moderate mitral regurgitation. Discussion: We present a case of high grade MSSA endocarditis in a young, healthy patient without pre-existing valvular disease, causing mitral valve perforation. Infective endocarditis remains a challenging diagnosis, and this case highlights the diagnostic utility of&amp;nbsp;FDG PET CT scan in such complex cases.

ODP068 A Case Report of Nivolumab Associated Hypercalcemia

Abstract Introduction Nivolumab is a human immunoglobulin G4 (IgG4) antibody which binds to programmed cell death receptor-1 (PD-1) and blocks the binding of PD-1 to either the PD-ligand 1 (PD-L1) or PD-L2 expressed on the surface of cancer cells. It has been approved for the treatment of melanoma, non-small cell lung cancer, renal cell carcinoma etc. Various endocrine immune-related adverse events including thyroiditis, hyper- and hypothyroidism, hypophysitis and type 1 diabetes has been described. We report a case of Nivolumab associated hypercalcemia. Case presentation 67-year-old female with history of CKD stage 3 with secondary hyperparathyroidism, melanoma of right ankle was admitted after one month of receiving the first dose of Nivolumab for her melanoma. She had altered mentation with elevated corrected calcium of 15.94(8.4-10.2) mg/dl. Prior calcium levels were in low to normal range, eGFR was 13, creatinine elevated at 3.4 (0.57-1.11) mg/dl, PTH 84 (10-65) pg/ml, 25 OH vitamin D 54 (30-74) ng/ml, Phosphorus normal, Magnesium normal, 1,25-OH vitamin D was elevated at 103(18-72) pg/ml, PTHrp normal, normal SPEP, normal TSH, no history of fractures, normal DXA, no history of kidney stones, not on any calcium supplements, not on thiazide or lithium. Chest x ray and NM full body PET CT did not show any evidence of granulomatous disease except for recurrence and metastasis of melanoma in right thigh, calf, and ankle. No family history of kidney stones or hypercalcemia. Patient was treated with IV fluids and Calcitonin. Her calcium quickly improved to 9.9 within 48 hours. Within 3 weeks of discharge, she was readmitted for elevated calcium of 14.4 mg/dl, creatinine 2.29 mg/dl, eGFR 21, PTH 96 pg/ml, Mg 1.8 (1.6-2.6) mg/dl. She was treated with IV fluids and calcitonin and calcium normalized within 48 hours. Parathyroid scan did not show any parathyroid adenoma. She was started on prednisone for possible Nivolumab associated immune adverse reaction. She was also briefly treated with cinacalcet which was discontinued. Prednisone was tapered and then stopped over the course of 6 weeks. Calcium remains normal. PTH remains slightly elevated which is thought to be due to secondary hyperparathyroidism from CKD. Normal cortisol level. Discussion This is likely a case of Nivolumab associated hypercalcemia given the onset soon after immunotherapy initiation and improvement with glucocorticoid therapy. Immunotherapy was not resumed after the first dose due to recurrent severe hypercalcemia. The patient is currently under surveillance for melanoma. Calcium level remains normal. Although it is rare, a few cases of Nivolumab associated hypercalcemia have been reported previously. Exact mechanism is not known but it has been speculated that macrophage activation by Nivolumab can cause increased level of 25(OH) D-hydroxylase with increased conversion of 25-OH vitamin D to 1,25-OH vitamin D resulting in calcitriol mediated hypercalcemia. Presentation: No date and time listed

Magnetic resonance tomography of the lungs with paramagnetic contrast enhancement in dynamic follow-up control of treatment of lung cancer in radiophobic patient: a case report

Till now the facilities of MRI with paramagnetic contrast enhancement (CE-MRI) in detection of lung tumors remain underused and almost ignored. A clinical case of primary detection and prospective follow-up of lung cancer in a patient whose MRI of the chest revealed a tumor lesion — a central cancer of the left lung, in particular a lesion of the bronchus of the lower lobe of the left lung. MRI of the chest with paramagnetic contrast enhancement was carried out as part of the whole body CE-MRI study after the complex therapy of breast cancer, and both the primary lung tumor and metastatic lesion of mediastinal — subbifurcation lymph nodes were revealed. With a transbronchial biopsy, the diagnosis of lung cancer was verified. Chemotherapy (ChT) was started using the vinorelbin/ carboplatin regimen. After this, the CE-MRI has been carried out during the whole period of followup of anti-cancer chemotherapy. At the CE-MRI during the first course of ChT visually the complete regression of the disease, also with clinical remission was achieved. However, the ChT scheme was not fully completed due to the patient’s departure for urgent private reasons. Two months later, the patient was examined again according to the same CE-MRI protocol, while a relapse of the disease was detected with a more pronounced lesion of the mediastinal lymph nodes than during the initial treatment. ChT with vinorelbine/carboplatin was again carried out under the control CE-MRI, this time completely. According to the chest CE-MRI, visual remission was achieved, with the disappearance of nodular tumor at the site of the previously identified primary tumor of lung cancer and metastatic lesions of lymph nodes. Thus, it was the CE-MRI which provided the early diagnosis and adequate control of treatment of the lung cancer with extensive local lymph nodes spread. After this CE-MRI, the whole body PET with 18F-fluorodeoxyglucose (FDG) was also performed and no signs of relapse or continued tumor growth were revealed. Five months after this stage, the patient did persist to stay completely preserved clinically, at work and socially active. Thus, the chest CE-MRI can be employed for the follow-up of the tumor process in lung cancer, as necessary, without radiation exposure, without limiting the number and frequency of studies.

Assessing owners' readiness to change their behaviour to address their companion animal's obesity.

Owner behaviour change in relation to management is critical for successful pet weight loss. The stages of change (SOC) can be used to conceptualise the process of intentional behaviour change. Clients may be more likely to make successful changes when practitioners use communication techniques appropriate for a client's current stage. The objective of this cross-sectional study was to assess pet owners' SOC in relation to managing the weight of their overweight or obese pet. An online questionnaire targeting dog and cat owners was distributed via snowball sampling. A total of 532 questionnaires were included in the analysis. Of these, 153 participants (28.8%) self-identified their pet's body condition score (BCS) as greater than 5 (on a nine-point scale). An adapted University of Rhode Island Change Assessment scale was completed by 119 of these participants (77.8%) to assess their readiness to change related to managing their overweight or obese pet. Most participants were scored in the precontemplation (52.1%) and contemplation (42%) stages, where readiness to change is low. Owner assessments likely resulted in underestimation of pets' BCS. The results offer preliminary insight into the SOC of owners who identify their pets as overweight or obese. Developing tools to assess and understand owners' readiness to change may be useful in informing veterinary professionals' communication approaches when engaging in weight management conversations.

Exploring veterinary professionals' perceptions of pet weight-related communication in companion animal veterinary practice.

Pet obesity is commonly encountered by veterinary professionals, yet little is known about their perception of communicating about pet weight. The objective of this study was to explore veterinary professionals' perception of discussing pet obesity with clients. An online survey targeting veterinary professionals was distributed via social media and veterinary organisation newsletters. Topics included respondents' perceptions of weight-related communication, factors related to approaching weight conversations and implicit weight bias. A total of 102 respondents to the survey were included in the final analysis. Avoidance of discussing pet obesity with certain clients was common (53.9%; 55/102). The most endorsed term for describing pets with excess weight to clients was 'overweight' (97.1%; 99/102). The pet's body condition score was rated the most important factor to consider when deciding how to approach a weight discussion with clients. Although only 29 participants completed the implicit association test (IAT), most of these participants were identified as having an unconscious preference for thin people. The small sample size limited the vignette analysis to descriptive only, and the IAT results should be interpreted cautiously. This exploratory, cross-sectional study provides early insight into veterinary professionals' perceptions of pet obesity-related communication and suggests the presence of weight bias in the profession that warrants further investigation.

An indolent presentation of brain abscess due to a slow growing organism

Propioni bacterium propionicum is an anaerobic gram positive bacteria. It’s rarely described as to cause brain abscess. We report the isolation of this organism from a brain abscess and emphasise the problems associated with it’s diagnosis. A 62 year old lady with a history of acromegaly underwent emergency surgery for recurrent pituitary lesion felt to be apoplexy. Four weeks later she presented with headache and confusion. Co morbidities included autoimmune diseases on long term steroids and previous use of immunosuppressants. Clinical examination showed neck stiffness. Brain MRI demonstrated an enhancing lesion in the fourth ventricle causing secondary obstructive hydrocephalus requiring endoscopic third ventriculostomy. Blood tests, CSF analysis and whole body PET scan were unable to differentiate between infection and malignancy. Excision of the lesion was felt very high risk as deep in the tectal area. A sporadic trial of antibiotics, high dose steroids and immunotherapy was tried. Patient developed worsening headache with progression of the lesion. Underwent craniotomy and pus was found which isolated P. propionicum sensitive to penicillin and betalactams. Treated with intravenous meropenem for a year. There was significant reduction in the size of the abscess and hydrocephalus on brain MRI at 8 months post-diagnosis. P. propionicum has been isolated and associated with lesions of the lacrimal glands, lung and abdomen. We could find only two case reports of brain abscess due to P. propionicum. Identification of P.propionicum in the microbiology laboratory can be difficult requiring anaerobic growth conditions and extended cultures. Treatment is prolonged antimicrobial therapy.

Estudio comparativo de la sensibilidad del MAMMI-PET en el diagnóstico de cáncer de mama con respecto a otras pruebas de imagen

IntroductionThe use of mammo dedicated breast PET (dbPET) scanners improves spacial resolution compared to Whole Body Pet images (WBPET). Mammography with Molecular Imaging PET (MAMMI-PET) is a new device with hardly any clinical studies. The aim of the study is to estimate the sensitivity of MAMMI-PET and compare it with classic imaging devices. Material and methodsA prospective and analytical observational study was carried out in a sample of patients with histologically confirmed breast cancer who were treated at our hospital between January 2017 and November 2018. Preoperative study of patients was performed with ultrasound, mammography, Magnetic Resonance Imaging (MRI) and MAMMI-PET. Findings (number and benignant/malignant lesions) of the anatomopathological (AP) study were used as the gold standard. Results between MAMMI-PET and AP were compared. The sensitivity of each test was compared with that of the MAMMI-PET using the Chi square test with a significance level of 0.05. ResultsData from 32 patients and 44 lesions (36 malignant and 8 benign) were evaluated. Two patients were excluded. The MAMMI-PET sensitivity was 75%. The best sensitivity was obtained for MRI with 85.3%, while for ultrasound and mammography it was 77.8% and 69.4% respectively. No statistically significant differences were found between the sensitivity of MAMMIPET and the rest of the imaging tests. ConclusionsThe sensitivity obtained for the MAMMI-PET scanner (75%) was similar to the other imaging tests.

Artificial intelligence-based PET denoising could allow a two-fold reduction in [18F]FDG PET acquisition time in digital PET/CT

PurposeWe investigated whether artificial intelligence (AI)-based denoising halves PET acquisition time in digital PET/CT.MethodsOne hundred ninety-five patients referred for [18F]FDG PET/CT were prospectively included. Body PET acquisitions were performed in list mode. Original “PET90” (90 s/bed position) was compared to reconstructed ½-duration PET (45 s/bed position) with and without AI-denoising, “PET45AI and PET45”. Denoising was performed by SubtlePET™ using deep convolutional neural networks. Visual global image quality (IQ) 3-point scores and lesion detectability were evaluated. Lesion maximal and peak standardized uptake values using lean body mass (SULmax and SULpeak), metabolic volumes (MV), and liver SULmean were measured, including both standard and EARL1 (European Association of Nuclear Medicine Research Ltd) compliant SUL. Lesion-to-liver SUL ratios (LLR) and liver coefficients of variation (CVliv) were calculated.ResultsPET45 showed mediocre IQ (scored poor in 8% and moderate in 68%) and lesion concordance rate with PET90 (88.7%). In PET45AI, IQ scores were similar to PET90 (P = 0.80), good in 92% and moderate in 8% for both. The lesion concordance rate between PET90 and PET45AI was 836/856 (97.7%), with 7 lesions (0.8%) only detected in PET90 and 13 (1.5%) exclusively in PET45AI. Lesion EARL1 SULpeak was not significantly different between both PET (P = 0.09). Lesion standard SULpeak, standard and EARL1 SULmax, LLR and CVliv were lower in PET45AI than in PET90 (P < 0.0001), while lesion MV and liver SULmean were higher (P < 0.0001). Good to excellent intraclass correlation coefficients (ICC) between PET90 and PET45AI were observed for lesion SUL and MV (ICC ≥ 0.97) and for liver SULmean (ICC ≥ 0.87).ConclusionAI allows [18F]FDG PET duration in digital PET/CT to be halved, while restoring degraded ½-duration PET image quality. Future multicentric studies, including other PET radiopharmaceuticals, are warranted.

P394 FROM A PET THE FIRST AND UNEXPECTED DIAGNOSTIC ORIENTATION

Abstract Introduction Nuclear medicine plays an important role in the diagnosis and treatment of numerous pathologies. In the cardiology field it can be used to obtain a lot of information about ischemic heart disease, infiltrative heart disease and inflammatory and infectious diseases such as endocarditis. The greatest impact in the field of these latter pathologies was obtained using F–fluorodeoxyglucose (FDG) in the study of patients with implantable electronic devices and replaced valves or valve prostheses. In this regard, I report the case of a patient with results of valve tube implantation in which a PET performed to investigate an inflammatory pathology has allowed to make a diagnosis of endocarditis. Discussion The case concerns a 66–year–old man subjected to intervention of Bentall for type A aortic dissection (in 2015); chronic aortic dissection remains (Stanford B). Diabetic with chronic renal failure and COPD. Recovered in medicine for low back pain, dysuria and episodes of chills without pyrexia. High inflammatory indices but with urine culture and negative blood cultures performed on isolated febrile peak. CT scan of the chest negative for phlogistic localizations and for intense rachialgia in the suspicion of spondylodiscitis is subjected to total body PET that shows accumulation of radio compound in the first tract of the ascending aorta with greater anterior focality: hyper fixation is associated at the level of the lower limiter of L4 and L5. With these results therefore posed the suspicion of endocarditis for which started to perform transthoracic echocardiogram that did not identify certain pathological elements and transesophageal elements that instead showed suggestive images for endocarditic vegetation in aortic mechanical prosthesis (intravalvular mobile filiform appearance) and on the atrial side of the tricuspid valve (“soft” appearance of large dimensions). It is not associated with valvular dysfunction. After the echocardiographic finding, therapy with daptomycin in addition to piperacillin/tazobactam is initiated and the patient transferred to the infectious diseases department. Conclusions Bacterial endocarditis in particular in patients undergoing cardiac surgery or wearing implantable devices is often characterized by unusual clinical presentation as in this case, so it is not excessive to resort to second–level imaging such as transesophageal echocardiography and nuclear cardiology diagnostics.

Total-Body PET: Will It Change Science and Practice?

Total-body (TB) PET scanners with an axial field of view (AFOV) of at least 60 cm can image dynamic radiopharmaceutical distributions in the whole body. Although the benefits of the fine temporal sampling and dramatic increase in system sensitivity afforded by TB PET imaging have been postulated for

Accuracy Of Axillary Node Status On PET CT Scan In Predicting Nodal Metastases in Patients Having Sentinel Lymph Node Biopsy

Background: Sentinel lymph node biopsy (SLNBx) has become the standard of care for management of axilla in breast cancer. Currently, prior to SLNBx, axillary assessment is recommended by axillary ultrasound with/without FNAC or biopsy. Whole body PET CT scan is carried out as a staging investigations in many patients of breast cancer and suspicious axillary findings are reported. We have analyzed our database of SLNBx to assess the performance of whole body PET CT as a predictor of sentinel node metastases.

Potential and Most Relevant Applications of Total Body PET/CT Imaging.

The introduction of total body (TB) PET/CT instruments over the past 2 years has initiated a new and exciting era in medical imaging. These instruments have substantially higher sensitivity (up to 68 times) than conventional modalities and therefore allow imaging the entire body over a short period. However, we need to further refine the imaging protocols of this instrument for different indications. Total body PET will allow accurate assessment of the extent of disease, particularly, including the entire axial and appendicular skeleton. Furthermore, delayed imaging with this instrument may enhance the sensitivity of PET for some types of cancer. Also, this modality may improve the detection of venous thrombosis, a common complication of cancer and chemotherapy, in the extremities and help prevent pulmonary embolism. Total body PET allows assessment of atherosclerotic plaques throughout the body as a systematic disease. Similarly, patients with widespread musculoskeletal disorders including both oncologic and nononcologic entities, such as degenerative joint disease, rheumatoid arthritis, and osteoporosis, may benefit from the use of TB-PET. Finally, quantitative global disease assessment provided by this approach will be superior to conventional measurements, which do not reflect overall disease activity. In conclusion, TB-PET imaging may have a revolutionary impact on day-to-day practice of medicine and may become the leading imaging modality in the future.

Predictive potential of ACE phenotyping in extrapulmonary sarcoidosis

Elevated ACE expression in tissues (reflected by blood ACE levels) is associated with increased risk of cardiovascular diseases and is also a marker for granulomatous diseases. We developed a new approach for characterization of ACE status in the blood—ACE phenotyping and established normal values of ACE levels 50–150% of control pooled plasma. ACE phenotyping was performed in citrated plasma of 120 patients with known interstitial lung diseases. In the 1st set of 100 patients we found 22 patients with ACE levels > 150%; ACE phenotyping also objectively identified the presence of ACE inhibitors in the plasma of 15 patients. After excluding these patients and patient with ACE mutation that increases ACE shedding, 17 patients were identified as a suspicious for systemic sarcoidosis based on elevation of blood ACE (> 150% of mean). A new parameter that we have established–ACE immunoreactivity (with mAb 9B9)—allowed us to detect 22 patients with decreased values (< 80%) of this parameter, which may indicate the presence of ACE in the blood that originates from macrophages/dendritic cells of granulomas. In the remaining 20 patients, this new parameter (mAbs binding/activity ratio) was calculated using 3 mAbs (9B9, 3A5 and i1A8—having overlapping epitopes), and 8 patients were identified as having decreases in this parameter, thus increasing dramatically the sensitivity for detection of patients with systemic sarcoidosis. Whole body PET scan confirmed extrapulmonary granulomas in some patients with lower immunoreactivity towards anti-ACE mAbs. ACE phenotyping has novel potential to noninvasively detect patients with systemic sarcoidosis.