Focal FDG Uptake Research Articles

Use of Laxative-Augmented Contrast Medium Increases the Accuracy in the Detection of Colorectal Neoplasms.

Colonic adenomas are considered a precursor of colorectal cancer. A 75-year-old woman had a history of post-operation left breast cancer. She received an excision when the left chest wall recurred. A later FDG PET/CT scan revealed a focal intense FDG accumulation in the sigmoid, a focal mild FDG uptake in the pericolic lymph node, and a focal increased FDG accumulation in the transverse colon. A delayed FDG PET/CT scan after the per-rectal administration of the laxative-augmented contrast medium revealed a filling defect with persistent FDG uptake in the sigmoid and transverse colon and mild FDG uptake in the pericolic lymph node. In addition, more lesions were observed in the rectum and descending colon. The pathology reports showed sigmoid adenocarcinoma with lymph node metastasis, and adenomas in the transverse colon, descending colon, and rectum.

FDG PET/MRI in a Case of Isolated Abdominal Incisional Site Metastasis After Laparoscopic Surgery for Colon Cancer.

Abdominal-wall metastasis following laparoscopic surgery for colorectal cancer is rare. We describe FDG PET/MRI findings in a case of isolated abdominal incisional site metastasis after laparoscopic surgery for colon cancer. The abdominal-wall metastasis showed slight hyperintensity on T2-weighted fat-suppressed image and intense focal FDG uptake on PET. This case demonstrates the usefulness of FDG PET/MRI in detecting the atypical metastasis from colon cancer.

E026 Severe odynophagia due to cricoarytenoid arthritis in a patient with rheumatoid arthritis and systemic lupus erythematosus

Abstract Background/Aims A 65-year-old man with a 20-year history of rheumatoid arthritis (RA) presented with dysphagia, odynophagia, polyarthralgia and significant weight loss. Methods - Results In addition to raised markers of inflammation, he was anti-nuclear antibody, anti-dsDNA antibody, anti-chromatin antibody and rheumatoid factor positive. He was initiated on 20mg once daily prednisolone but reported continued dysphagia and odynophagia. Computerised tomography (CT) of the neck revealed sclerosis at both cricoarytenoid joints with positron emission tomography (PET-CT) imaging identifying focal FDG uptake in the right hemiglottis projected over the posterior right true cord. Direct visualisation showed reduced mobility of the arytenoids with incomplete glottic closure in the absence of other abnormalities. He was diagnosed with cricoarytenoid (CA) joint arthritis on a background of RA and systemic lupus erythematosus overlap, with the resolution of his symptoms following intravenous methylprednisolone. Conclusion CA arthritis is an increasingly rare manifestation of autoimmune disease, and severe ongoing odynophagia an atypical presentation. This case highlights the need for continued awareness of laryngeal manifestations of autoimmune disease and demonstrates the benefit of PET-CT in cases where the diagnosis is uncertain or delayed. Disclosure J.S. Berry: None. J. Robinson: None. W. Ng: Consultancies; Expert advice in the area of Sjogren’s syndrome to GlaxoSmithKline, MedImmune, UCB, Abbvie, Roche, Eli Lilly, Takeda, Resolves Therapeutics, Sanofi, Novartis and BMS.

False Liver Metastasis by Positron Emission Tomography/Computed Tomography Scan after Chemoradiotherapy for Esophageal Cancer-Potential Overstaged Pitfalls of Treatment.

In patients with esophageal cancer undergoing neoadjuvant chemoradiotherapy (nCRT), subsequent restaging with F-18-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) can reveal the presence of interval metastases, such as liver metastases, in approximately 10% of cases. Nevertheless, it is not uncommon in clinical practice to observe focal FDG uptake in the liver that is not associated with liver metastases but rather with radiation-induced liver injury (RILI), which can result in the overstaging of the disease. Liver radiation damage is also a concern during distal esophageal cancer radiotherapy due to its proximity to the left liver lobe, typically included in the radiation field. Post-CRT, if FDG activity appears in the left or caudate liver lobes, a thorough investigation is needed to confirm or rule out distant metastases. The increased FDG uptake in liver lobes post-CRT often presents a diagnostic dilemma. Distinguishing between radiation-induced liver disease and metastasis is vital for appropriate patient management, necessitating a combination of imaging techniques and an understanding of the factors influencing the radiation response. Diagnosis involves identifying new foci of hepatic FDG avidity on PET/CT scans. Geographic regions of hypoattenuation on CT and well-demarcated regions with specific enhancement patterns on contrast-enhanced CT scans and MRI are characteristic of radiation-induced liver disease (RILD). Lack of mass effect on all three modalities (CT, MRI, PET) indicates RILD. Resolution of abnormalities on subsequent examinations also helps in diagnosing RILD. Moreover, it can also help to rule out occult metastases, thereby excluding those patients from further surgery who will not benefit from esophagectomy with curative intent.

FDG PET/CT in Solitary Isolated Renal Metastasis From Squamous Cell Lung Cancer.

We describe FDG PET/CT findings in a patient with a solitary isolated renal metastasis from squamous cell lung cancer. The renal metastasis appeared as a small focus of activity at the renal cortex on FDG PET/CT at initial staging of the lung tumor, misinterpreted as cortical tracer retention, and was significantly enlarged on the second FDG PET/CT performed 4 months after the first PET/CT. This case demonstrates the usefulness of FDG PET/CT in identifying unexpected extrathoracic metastasis from lung cancer. Focal FDG uptake in the renal cortical region in a cancer patient should be evaluated carefully to avoid misdiagnosis.

Pre-treatment 18f-FDG PET/CT for Assessing and Predicting Bone Marrow Involvement in Patients with Newly Diagnosed Peripheral T-Cell Lymphoma

Objective: To explore the value of 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in assessing and predicting bone marrow involvement (BMI) in patients with newly diagnosed peripheral T-cell lymphoma (PTCL) prior to treatment. Methods: This retrospective study included 201 eligible patients of PTCL who received bone marrow biopsy (BMB) and PET/CT between January 2017 and December 2022. Extra subgroup analysis was designed considering the variation of avidity of FDG in different distinct entities. The status of bone marrow (BM) by PET was assessed using a visual examination and a quantitative index (the highest SUV of BM divided by the mean SUV of the liver [M/L]). Prognostic value of BM findings was also evaluated regarding progression free survival (PFS) and overall survival (OS). Results: The sensitivity and specificity of PET/CT for patients with confirmed PTCL by BMB were 43.2% and 90.2%, respectively. As for subgroup analysis, the kappa value reflecting the agreement between BMB and visual analysis in angioimmunoblastic T-cell lymphoma (AITL), peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), anaplastic large cell lymphoma (ALCL) as well as nodal T-follicular helper (TFH) cell lymphoma (PTCL-TFH) was 0.315, 0.307, 0.426 and 0.581, respectively. (Give the number of cases in each lymphoma group) PET score was an independent factor for PFS (P =0.011) but not for OS (P =0.840). In addition, 25 patients with stage I to II disease had no evidence of BMI by either PET/CT or BMB. Image-guided biopsy was also recommended when PET/CT showed a focal FDG uptake outside the iliac crest. Quantitative analysis revealed the differences in the two-level of M/L; however, they were not statistically significant for both PFS and OS (P =0.246 and P =0.227). Conclusion: PET/CT has a complementary role in assessing BMI and prognosis in PTCL patients.

Asymptomatic Penetrating Atherosclerotic Ulcer Findings on 18F-FDG PET/CT.

We present a case of an 84-year-old man with a history of smoking, hypertension, and coronary artery disease with an incidental spiculated left apical pulmonary nodule, suspicious for a stage I non-small cell lung cancer. 18F-FDG PET/CT performed for staging, which confirmed a small metabolically active pulmonary nodule. As an incidental finding, there was focal FDG uptake in the proximal descending aorta corresponding to a partially thrombosed outpouching of the aortic wall, in keeping with a penetrating atherosclerotic ulcer.

S2471 Incidental Focal FDG Uptake on PET-CT Scan Resulting in Diagnosis of a Large Tubulovillous Adenoma

S2471 Incidental Focal FDG Uptake on PET-CT Scan Resulting in Diagnosis of a Large Tubulovillous Adenoma

Diagnostic and Prognostic Value of 18F-FDG PET/CT in Bone Marrow Infiltration of Newly Diagnosed Diffuse Large B-Cell Lymphoma

To explore the diagnostic value of 18F-FDG PET/CT in bone marrow infiltration (BMI) of newly diagnosed diffuse large B-cell lymphoma (DLBCL), compared with the results of bone marrow biopsy (BMB) and investigate whether the BMI diagnosed by 18F-FDG PET/CT and other factors have independent prognostic values. Ninety-four newly diagnosed DLBCL patients who underwent PET/CT in Clinical Medical College of Shanghai General Hospital of Nanjing Medical University were included. BMB was performed within 2 weeks before or after PET/CT, and standardized treatment was performed after PET/CT. The manifestations of bone marrow (BM) FDG uptake were recorded. The diagnostic criteria of BMI were BMB positive or focal BM FDG uptake confirmed by imaging follow-up. The relationship between clinical features and BM FDG uptake and the values of PET/CT and BMB in the diagnosis of BMI was analyzed. The progression-free survival (PFS) was analyzed by Kaplan-Meier survival curves, log-rank test was used to compare PFS rate, and Cox regression model was used to analyze the independent risk factors affecting PFS. Among 94 DLBCL patients, 34 patients showed focal BM uptake (fPET), 7 patients showed super BM uptake (sBMU), 11 patients showed diffuse homogenous uptake higher than liver (dPET), and the other 42 patients had normal BM uptake (nPET) (lower than liver). BMB positive was found in all sBMU patients, in 20.6%(7/34) of fPET patients, and in 27.3% (3/11) of dPET patients. All nPET patients had negative BMB results. dPET patients were associated with lower hemoglobin level and leukocyte count compared with nPET group (P < 0.001, P =0.026). Compared with fPET patients, sBMU patients were more likely to have B symptoms and elevated lactate dehydrogenase (LDH). A total of 44 patients were diagnosed BMI, including 17 cases with BMB+. The sensitivity and specificity of BMB in the diagnosis of BMI was 38.6% (17/44) and 100% (50/50), respectively. Using fPET and sBMU as criteria of PET BMI, the diagnostic sensitivity and specificity of PET/CT was 93.2% (41/44) and 100% (50/50), respectively. Kaplan-Meier analysis showed that there was no significant difference in 2-year PFS rate between nPET and dPET patients (P >0.05), while sBMU patients had lower 2-year PFS rate compared with fPET patients (P < 0.001). Multivariate analysis showed that higher Ann Arbor stage (HR=9.010, P =0.04) and sBMU (HR=3.964, P =0.002) were independent risk factors affecting PFS. Increased BM FDG uptake of DLBCL can be manifested as dPET, fPET and sBMU. fPET and sBMU can replace BMB to diagnose BMI. Although dPET cannot completely exclude the possibility of BMI, it does not affect the prognosis, so it can be diagnosed as PET BMI negative. sBMU is an independent prognostic risk factor.

Evaluation of Colonoscopic Results of Patients with Incidental Colonic FDG Uptake in PET/CT Imaging.

Colorectal cancer is a significant global health concern, ranking as the second most deadly and third most common cancer worldwide. Early detection and removal of precancerous lesions play a crucial role in preventing cancer development and reducing mortality. Since FDG uptake is not specific for malignancy, incidental increased FDG uptake in the gastrointestinal tract may be challenging to interpret and may require further colonoscopic examination. This study aimed to investigate the features associated with malignant and premalignant pathology in patients with incidental colonic FDG uptake and determine the necessity of colonoscopy for each FDG uptake. Retrospective analysis was performed on data from patients who underwent colonoscopies between January 2016 and December 2021. Patients with FDG uptake in known colorectal malignancy regions were excluded. The study included 56 patients with incidental colonic FDG uptake. PET/CT images were visually and quantitatively analyzed, and the corresponding colonoscopy and histopathological results were recorded. Statistical analyses were conducted to evaluate the relationship between FDG uptake patterns, SUVmax values, and histopathological diagnoses. Colonoscopic findings were categorized as malignancy, polyps, and non-neoplastic lesions. Among the 56 patients with incidental colonic FDG uptake, 36 lesions were identified, and histopathology revealed malignancy in 10 (17.9%) patients and premalignant polyps in the 26 (46.4%) cases. Focal FDG uptake with corresponding wall thickening or soft tissue density on CT was associated with a higher likelihood of premalignant or malignant lesions. The SUVmax values demonstrated a significant difference between negative findings and polyps/malignancies. However, no significant difference was observed between malignant and premalignant lesions. A ROC curve analysis was made and assesed a cut-off value of 11.1 SUVmax (sensitivity: 83.3% and specificity: 90%) to distinguish premalignant or malignant lesions from non-malignant lesions. Incidental colonic FDG uptake with a focal pattern and corresponding CT findings were more likely to indicate premalignant or malignant lesions. SUVmax values were helpful in predicting the presence of pathological findings, but histopathological verification remains necessary for a definitive diagnosis. These findings contribute to our understanding of the clinical implications of incidental colonic FDG uptake and highlight the importance of follow-up colonoscopy for further evaluation.

PO-04-087 NOT ALL THAT SHINES IS GOLD AND NOT EVERY LIGHT UP ON PET SCAN IS CARDIAC SARCOIDOSIS

Cardiac sarcoidosis (CS) and arrhythmogenic right ventricular cardiomyopathy (ARVC) are rare conditions with different pathogenesis but often similar clinical and imaging findings. Therefore differential diagnosis could be challenging. We present a case of ARVC of insidious onset mimicking CS. N/A Our patient is a 51 year-old male with no cardiac history who presented to the emergency room (ER ) with frequent chest pain. Three years ago, work up resulted in negative coronary angiogram and cardiac MRI that showed focal myocardial inflammation so he was diagnosed with myocarditis. This time, he presented to the ER with chest pain and wide complex tachycardia [figure A]. Treatment with metoprolol terminated ventricular tachycardia. Echocardiography revealed normal biventricular function with mild right ventricular (RV) enlargement. The patient underwent PET myocardial perfusion scan that showed focal FDG uptake in the basal septal and inferolateral segments suspicious for sarcoidosis [figure B,C (FDG uptake - blue arrows)]. Repeated CMR demonstrated dilated RV with regional akinesis of the free wall and late gadolinium enhancement (LGE) of RV wall [figure D,E (LGE in right venticle wall-yellow arrows)]. No LGE in the left ventricle was noted. These CMR findings were consistent with ARVC. Due to the discrepancy in the results of both imaging modalities, genetic testing was utilized for further help with the diagnosis. Results were positive for PKP2 gene mutation which is highly suggestive of ARVC. Patient continued beta-blockers and was scheduled to have a defibrillator and genetic counselling. Although CS should be considered in every ARVC like presentation, the final diagnosis should not be built on PET scan results only. Genetic testing, tissue biopsy and even repeat cardiac MRI over the course of the disease are major pillars in such critical diagnosis.

Myocardial Inflammation on FDG PET/MRI and Clinical Outcomes in Symptomatic and Asymptomatic Participants after COVID-19 Vaccination.

To evaluate potential cardiac sequelae of COVID-19 vaccination at 2-month follow-up and relate cardiac symptoms to myocardial tissue changes on fluorodeoxyglucose (FDG) PET/MRI, blood biomarkers, health-related quality of life, and adverse outcomes. In this prospective study (ClinicalTrials.gov: NCT04967807), a convenience sample of individuals aged ≥17 years were enrolled after COVID-19 vaccination and were categorized as symptomatic myocarditis (new cardiac symptoms within 14 days of vaccination and met diagnostic criteria for acute myocarditis), symptomatic no myocarditis (new cardiac symptoms but did not meet criteria for myocarditis), and asymptomatic (no new cardiac symptoms). Standardized evaluation was performed 2 months after vaccination, including cardiac fluorine 18 FDG PET/MRI, blood biomarkers, and health-related quality of life. Statistical analysis included Kruskal-Wallis and Fisher exact tests. Fifty-four participants were evaluated a median of 72 days (IQR: 42, 91) after COVID-19 vaccination, 17 symptomatic with myocarditis (36±[SD]15 years, 13 males), 17 symptomatic without myocarditis (42±12 years, 7 males), and 20 asymptomatic (45±14 years, 9 males). No participants in the symptomatic without myocarditis or asymptomatic groups had focal FDG-uptake, myocardial edema or impaired ventricular function. Two participants with symptomatic myocarditis had focal FDG-uptake, and three had high T2 on MRI. Health-related quality of life was lower in the symptomatic myocarditis group than the asymptomatic group. There were no adverse cardiac events beyond myocarditis in any participant. At two-month follow-up, FDG PET/MRI showed evidence of myocardial inflammation in 2/17 participants diagnosed with acute myocarditis early after COVID-19 vaccination, but not in symptomatic and asymptomatic participants without acute myocarditis.Keywords: Myocarditis, Vaccination, COVID-19, PET/MRI, Cardiac MRI, FDG-PET.

Prevalence and clinical significance in our setting of incidental uptake in the thyroid gland found on 18F-fluordeoxyglucose positron emission tomography-computed tomography (PET-CT)

IntroductionThe expanding use of 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) has resulted in an increased frequency of incidentally discovered areas of FDG uptake within the thyroid gland. In these incidentalomas, high malignancy rates are reported. The study aimed, on the one hand, to determine the prevalence in our setting of thyroid incidentalomas in patients with no previous history of thyroid cancer undergoing an FDG PET-CT as well as the risk of malignancy and, on the other hand, to evaluate the usefulness of the maximum standard uptake value (SUVmax) for detecting thyroid cancer. Material and methodsThe FDG PET-CT scans performed at our hospital between June 2013 and December 2020 were retrospectively reviewed. In those incidentalomas with sufficient additional investigation, a diagnosis of benign or malignant was established based on the complementary tests. ResultsFrom the 21,594 PET-CT scans performed, 398 (1.8%) patients had an incidental FDG uptake, either focal (n=324) or diffuse (n=74). Among incidentalomas with further investigation, the rate of malignancy was higher in patients with focal FDG uptake than in those with diffuse uptake (26.5% versus 4%, respectively, p<0.05). The SUVmax value was significantly lower in benign focal lesions (5.7 [range: 2.3–66] than in malignant ones 10.6 [range: 3.1–51.2]; p<0.05). Nearly a quarter of malignant diagnoses (23.3%) were related to potentially aggressive tumours. ConclusionThe high rate of malignant tumours found among PET-CT incidentalomas and the high proportion of aggressive tumours demonstrate the need for a standardised approach in the investigation of incidental focal FDG uptake in the thyroid gland.

Prevalence and clinical significance in our setting of incidental uptake in the thyroid gland found on 18F-fluordeoxyglucose positron emission tomography-computed tomography (PET-CT)

IntroductionThe expanding use of 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) has resulted in an increased frequency of incidentally discovered areas of FDG uptake within the thyroid gland. In these incidentalomas, high malignancy rates are reported. The study aimed, on the one hand, to determine the prevalence in our setting of thyroid incidentalomas in patients with no previous history of thyroid cancer undergoing an FDG PET-CT as well as the risk of malignancy and, on the other hand, to evaluate the usefulness of the maximum standard uptake value (SUVmax) for detecting thyroid cancer. Material and methodsThe FDG PET-CT scans performed at our hospital between June 2013 and December 2020 were retrospectively reviewed. In those incidentalomas with sufficient additional investigation, a diagnosis of benign or malignant was established based on the complementary tests. ResultsFrom the 21,594 PET-CT scans performed, 398 (1.8%) patients had an incidental FDG uptake, either focal (n=324) or diffuse (n=74). Among incidentalomas with further investigation, the rate of malignancy was higher in patients with focal FDG uptake than in those with diffuse uptake (26.5% versus 4%, respectively, p<0.05). The SUVmax value was significantly lower in benign focal lesions (5.7 [range: 2.3–66] than in malignant ones 10.6 [range: 3.1–51.2]; p<0.05). Nearly a quarter of malignant diagnoses (23.3%) were related to potentially aggressive tumours. ConclusionThe high rate of malignant tumours found among PET-CT incidentalomas and the high proportion of aggressive tumours demonstrate the need for a standardised approach in the investigation of incidental focal FDG uptake in the thyroid gland.

Significance of incidental focal fluorine-18 fluorodeoxyglucose uptake in colon/rectum, thyroid, and prostate: With a brief literature review.

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT), a functional imaging method, is usually performed on the entire torso, and regions of unexpected suspicious focal hypermetabolism are not infrequently observed. Among the regions, colon, thyroid, and prostate were found to be the common organs in a recent umbrella review. Some studies reported that a high rate of malignancy was shown in incidentally identified focal hypermetabolic regions and suggested that further examinations should not be ignored. To investigate the malignancy rate of incidental focal FDG uptake, useful PET parameters and their cutoffs in discrimination between malignant and benign lesions. Retrospectively, the final reports of 16510 F-18 FDG PET/CT scans performed at our hospital between January 2016 and March 2022 were reviewed to identify incidentally observed FDG uptake in the colon/rectum, thyroid, and prostate. The scans of patients with current or prior malignancies at each corresponding location, without the final reports of histopathology or colonoscopy (for colon and rectum) for the corresponding hypermetabolic regions, or with diffuse (not focal) hypermetabolism were excluded. Finally, 88 regions of focal colorectal hypermetabolism in 85 patients (48 men and 37 women with mean age 67.0 ± 13.4 years and 63.4 ± 15.8 years, respectively), 48 focal thyroid uptakes in 48 patients (12 men and 36 women with mean age 62.2 ± 13.1 years and 60.8 ± 12.4 years, respectively), and 39 focal prostate uptakes in 39 patients (mean age 71.8 ± 7.5 years) were eligible for this study. For those unexpected focal hypermetabolic regions, rates of malignancy were calculated, PET parameters, such as standardized uptake value (SUV), capable of distinguishing between malignant and benign lesions were investigated, and the cutoffs of those PET parameters were determined by plotting receiver operating characteristic curves. In the colon and rectum, 29.5% (26/88) were malignant and 33.0% (29/88) were premalignant lesions. Both SUVmax and SUVpeak differentiated malignant/premalignant from benign lesions, however, no parameters could distinguish malignant from premalignant lesions. Higher area under the curve was shown with SUVmax (0.752, 95%CI: 0.649-0.856, P < 0.001) and the cutoff was 7.6. In the thyroid, 60.4% (29/48) were malignant. The majority were well-differentiated thyroid cancers (89.7%, 26/29). The results of BRAF mutation tests were available for 20 of the 26 well-differentiated thyroid cancers and all 20 had the mutation. Solely SUVmax differentiated malignant from benign lesions and the cutoff was 6.9. In the prostate, 56.4% (22/39) were malignant. Only SUVmax differentiated malignant from benign lesions and the cutoff was 3.8. Overall, among the 175 focal hypermetabolic regions, 60.6% (106/175) were proven to be malignant and premalignant (in colon and rectum) lesions. Approximately 60% of the incidentally observed focal F-18 FDG uptake in the colon/rectum, thyroid, and prostate were found to be malignant. Of the several PET parameters, SUVmax was superior to others in distinguishing between malignant/premalignant and benign lesions. Based on these findings, incidental focal hypermetabolism should not be ignored and lead physicians to conduct further investigations with greater confidence.

Abstract 15827: A Case of Ventricular Arrhythmia as Presentation for Cardiac Involvement of Polymyositis

Introduction: Polymyositis is an autoimmune systemic disease which is characterized by chronic weakness and inflammation in skeletal muscle predominantly. Cardiac involvement has been reported and is a poor prognostic factor. Clinical course 61-year-old male with biopsy proven polymyositis with history of cardiac arrest secondary to ventricular fibrillation and dual chamber automatic implantable cardioverter defibrillator (AICD) implanted for secondary prevention. He had recurrent PVC-induced ventricular fibrillation causing AICD shocks. Eventually, he underwent electrophysiology study and successful ablation of PVC targeted to the basal lateral left ventricle.Transthoracic echocardiogram showed unremarkable systolic and akinetic basal inferolateral wall segment.He underwent PET-CT of myocardium which showed focal FDG uptake of the lateral basal left ventricular could indicate focal myocarditis.Endomyocardial biopsy did not show any evidence of myocarditis.Eventually he had recurrent rapid monomorphic ventricular tachycardia and was briefly placed on amiodarone. He was placed on immunosuppressive therapy managed by Rheumatology with etanercept, rituximab and IVIG. No recurrence of ventricular arrythmia has occurred since. Amiodarone has been discontinued. Discussion: Myocardial involvement of polymyositis is not uncommon and has been noted to increase morbidity and mortality.The most common reported manifestations include congestive heart failure, conduction abnormalities which can range from ventricular arrhythmia to complete heart block and coronary artery disease. ConclusionIt is very important to recognize polymyositis as a cause for ventricular arrhythmias in the right clinical setting as management with immunosuppressive therapy can decrease the burden in ventricular arrhythmias.

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.

18F-FDG PET/CT Imaging of G-CSF-Producing Inflammatory Myofibroblastic Tumor of the Pleura.

We report a case of granulocyte colony-stimulating factor (G-CSF)-producing inflammatory myofibroblastic tumor of the pleura in a 71-year-old man. Contrast-enhanced CT demonstrated multiple pleural masses with pulmonary hilar lymph nodes swelling. 18F-FDG PET/CT demonstrated marked focal FDG uptake in the thoracic masses with diffuse uptake in the bone marrow. Based on the pathological findings and elevated serum G-CSF level, the patient was diagnosed as G-CSF-producing inflammatory myofibroblastic tumor. Because G-CSF-producing tumors demonstrate aggressive clinical course, early and accurate diagnosis is important.

Combined SUVmax and localized colonic wall thickening parameters to identify high-risk lesions from incidental focal colorectal 18F-FDG uptake foci.

ObjectiveTo evaluate the detection ability of 18F-FDG PET/CT for identifying high-risk lesions (high-risk adenomas and adenocarcinoma) from incidental focal colorectal 18F-FDG uptake foci combining maximum standard uptake value (SUVmax) and localized colonic wall thickening (CWT). The secondary objective was to investigate the factors of missed detection of high-risk adenomas by 18F-FDG PET/CT.Patients and methodsA total of 6394 patients who underwent 18F-FDG PET/CT in our hospital from August 2019 to December 2021 were retrospectively analysed, and 145 patients with incidental focal colorectal 18F-FDG uptake foci were identified. The optimal cut-off value of SUVmax for 18F-FDG PET/CT diagnosis of high-risk lesions was determined by receiver operating characteristic (ROC) curves. SUVmax and localized CWT were combined to identify high-risk lesions from incidental focal colorectal 18F-FDG uptake foci. The characteristics of incidental adenomas detected and high-risk adenomas missed by 18F-FDG PET/CT were compared.ResultsOf the 6394 patients, 145 patients were found to have incidental focal colorectal FDG uptake foci (2.3%), and 44 patients underwent colonoscopy and pathological examination at the same time. In fact, 45 lesions, including 12 low-risk lesions and 33 high-risk lesions (22 high-risk adenomas, 11 adenocarcinoma), were found by colonoscopy. The area under the ROC curve of SUVmax for low-risk lesions and high-risk lesions was 0.737, and the optimal cut-off value was 6.45 (with a sensitivity of 87.9% and specificity of 58.3%). When SUVmax ≥6.45, the combination of localized CWT parameters has little influence on the sensitivity and specificity of detection; when SUVmax <6.45, the combination of localized CWT parameters can improve the specificity of detection of high-risk lesions, but the sensitivity has little change. In addition, the size of high-risk adenomas discovered incidentally by 18F-FDG PET/CT was larger than that of high-risk adenomas missed, but there was no significant difference in lesion location, pathological type or intraepithelial neoplasia between the two groups.ConclusionsThe combination of SUVmax and localized CWT parameters of 18F-FDG PET/CT helped identify high-risk lesions from incidental focal colorectal 18F-FDG uptake foci, especially for lesions with SUVmax <6.45. Lesion size may be the only factor in 18F-FDG PET/CT missing high-risk adenomas.

Multimodality imaging to distinguish between benign and malignant cardiac masses

BackgroundTo compare the diagnostic accuracy of CMR and FDG-PET/CT and their complementary role to distinguish benign vs malignant cardiac masses. MethodsRetrospectively assessed patients with cardiac mass who underwent CMR and FDG-PET/CT within a month between 2003 and 2018. Results72 patients who had CMR and FDG-PET/CT were included. 25 patients (35%) were diagnosed with benign and 47 (65%) were diagnosed with malignant masses. 56 patients had histological correlation: 9 benign and 47 malignant masses. CMR and FDG-PET/CT had a high accuracy in differentiating benign vs malignant masses, with the presence of CMR features demonstrating a higher sensitivity (98%), while FDG uptake with SUVmax/blood pool ≥ 3.0 demonstrating a high specificity (88%). Combining multiple (> 4) CMR features and FDG uptake (SUVmax/blood pool ratio ≥ 3.0) yielded a sensitivity of 85% and specificity of 88% to diagnose malignant masses. Over a mean follow-up of 2.6 years (IQR 0.3-3.8 years), risk-adjusted mortality were highest among patients with an infiltrative border on CMR (adjusted HR 3.1; 95% CI 1.5-6.5; P = .002) or focal extracardiac FDG uptake (adjusted HR 3.8; 95% CI 1.9-7.7; P < .001). ConclusionAlthough CMR and FDG-PET/CT can independently diagnose benign and malignant masses, the combination of these modalities provides complementary value in select cases.