Abnormal Uptake Research Articles

Incidental Detection of Ilium Langerhans Cell Histiocytosis on 99mTc-DTPA Renal Dynamic Scintigraphy.

We report the case of a 24-year-old man who underwent 99mTc-DTPA scintigraphy for the evaluation the renal function. This scan incidentally showed an abnormal uptake of 99mTc-DTPA in the left lower abdominal region. SPECT/CT fusion images showed osteolytic bone destruction in the left ilium associated with soft tissue mass and elevated DTPA uptake. Biopsy pathology of the ilium lesion demonstrated Langerhans cell histiocytosis.

Early Brain Amyloid Accumulation at PET in Military Instructors Exposed to Subconcussive Blast Injuries.

Background Traumatic brain injury (TBI) is the leading cause of disability in young adults. Recurrent TBI is associated with a range of neurologic sequelae, but the contributing factors behind the development of such chronic encephalopathy are poorly understood. Purpose To quantify early amyloid β deposition in the brain of otherwise healthy adult men exposed to repeated subconcussive blast injury using amyloid PET. Materials and Methods In this prospective study from January 2020 to December 2021, military instructors who were routinely exposed to repeated blast events were evaluated at two different points: baseline (before blast exposure from breacher or grenade) and approximately 5 months after baseline (after blast exposure). Age-matched healthy control participants not exposed to blasts and without a history of brain injury were evaluated at similar two points. Neurocognitive evaluation was performed with standard neuropsychologic testing in both groups. Analysis of PET data consisted of standardized uptake value measurements in six relevant brain regions and a whole-brain voxel-based statistical approach. Results Participants were men (nine control participants [median age, 33 years; IQR, 32-36 years] and nine blast-exposed participants [median age, 33 years; IQR, 30-34 years]; P = .82). In the blast-exposed participants, four brain regions showed significantly increased amyloid deposition after blast exposure: inferomedial frontal lobe (P = .004), precuneus (P = .02), anterior cingulum (P = .002), and superior parietal lobule (P = .003). No amyloid deposition was observed in the control participants. Discriminant analysis on the basis of regional changes of amyloid accumulation correctly classified the nine healthy control participants as healthy control participants (100%), and seven of the nine blast-exposed participants (78%) were correctly classified as blast exposed. Based on the voxel-based analysis, whole-brain parametric maps of early abnormal early amyloid uptake were obtained. Conclusion Early brain amyloid accumulation was identified and quantified at PET in otherwise healthy adult men exposed to repetitive subconcussive traumatic events. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Haller in this issue.

First case report of splenomegaly with splenic infarction due to aortic graft infection

BackgroundDiagnosis of aortic graft infections (AGI) is challenging. Here, we report a case of AGI with splenomegaly and splenic infarction.Case presentationA 46-year-old man who underwent total arch replacement for Stanford type A acute aortic dissection one year prior presented to our department with fever, night sweat, and a 20-kg weight loss over several months. Contrast-enhanced computed tomography (CT) revealed splenic infarction with splenomegaly, fluid collection, and thrombus around the stent graft. Positron emission tomography-CT (PET-CT) revealed abnormal 18F-fluorodeoxyglucose uptake in the stent graft and spleen. Transesophageal echocardiography revealed no vegetations. The patient was diagnosed with an AGI and underwent graft replacement. Blood and tissue cultures in the stent graft yielded Enterococcus faecalis. After the surgery, the patient was successfully treated with antibiotics.ConclusionsSplenic infarction and splenomegaly are the clinical findings of endocarditis but are rare in graft infection. These findings could be helpful to diagnose graft infections, which is often challenging.

Abstract #1407012: ACTH Producing Pituitary Adenoma Found After Transsphenoidal Resection of Meningioma

ACTH-dependent Cushing's disease (CD) is a condition characterized by pituitary hypersecretion of ACTH, leading to adrenal cortisol upregulation. Hypercortisolism has long-term complications, notably metabolic syndrome, cardiovascular disease, and osteoporosis, to name a few. The incidence of CD is approximately 1-2 cases per million. ACTH can be secreted by pituitary macroadenomas and microadenomas, and in some cases, ectopic sources. This case report describes a case of ACTH-dependent CD caused by a pituitary microadenoma with a history of planum sphenoidal meningioma. 48-year-old female with a past medical history of planum sphenoidal meningioma s/p transsphenoidal partial resection, central hypothyroidism on levothyroxine, and hypogonadotropic hypogonadism presented with worsening truncal obesity and prediabetes. The physical exam was remarkable for obesity and hyperpigmentation of knuckles. Labs were significant for elevated AM cortisol at 27.2 mcg/dL with a significantly elevated ACTH level of 81.8 pg/L. Saliva cortisol at 11pm was also mildly elevated at 0.154 ug/dL. The cortisol level was not suppressed with the low-dose dexamethasone suppression test at 8.5 mcg/dL, while High-dose dexamethasone suppressed cortisol to 2.0 mcg/dL, indicating a possible pituitary source. Other biochemical tests such as Prolactin, TSH, and HGH levels were normal. MRI of the pituitary was performed to locate the potential source and was significant for hypo-enhancing lesions suspicious for bilateral synchronous pituitary microadenomas (9x5 mm right and 4x4 mm left). To confirm that there are no ectopic sources for the ACTH, a PET Dotatate scan was done and showed hypermetabolic meningioma corresponding to the findings of the pituitary MRI and confirmed no other abnormal focal radiotracer uptake. Non-functioning pituitary tumors are common, hence, to confirm the pituitary source of ACTH prior to surgery, she underwent inferior petrosal sinus sampling (IPSS). This revealed a significantly elevated ACTH secretion from the right microadenoma. Transsphenoidal resection of the pituitary tumor was performed. Post-procedure, AM cortisol levels were undetectable and ACTH level was low at 5.8 pg/mL. She was then started on hydrocortisone for presumed adrenal insufficiency post pituitary lesion resection. No signs of diabetes insipidus were shown after surgery—the patient will follow up with endocrinology for eventual weaning off hydrocortisone. Simultaneous occurrence of pituitary adenoma and meningioma without a history of radiotherapy is extremely rare, with only 49 cases described before 2019. Even more rare, is an ACTH secreting pituitary adenoma coexisting with a meningioma. IPSS procedure was performed after MRI in this case to get even more accurate localization of the source before surgical excision, as it is the best test to differentiate pituitary from ectopic ACTH-dependent Cushing’s. In approximately 1 out of 3 patients, remission is not achieved with surgical excision alone. For this reason, patients need post-operative monitoring and secondary medications to control their symptoms.

Quantitative brain 18F-FDG PET/CT analysis in seronegative autoimmune encephalitis (P11-3.005)

<h3>Objective:</h3> To determine if PET/CT is abnormal in less differentiated forms of autoimmune encephalitis (AE), including seronegative AE and steroid-responsive encephalopathy with associated thyroiditis (SREAT), and whether specific patterns of dysmetabolism exist. <h3>Background:</h3> Brain ¹⁸F-FDG PET/CT (PET) has been established as a useful tool in evaluating AE. Specific patterns of dysmetabolism have been identified in patients with anti-N-methyl-D-aspartate (NMDA) and anti-leucine-rich-glioma-inactivated-1 (LGI-1) AE, and preliminary evidence suggests that PET dysmetabolism may correlate with clinical functional status. <h3>Design/Methods:</h3> We conducted a retrospective cross-sectional analysis of PET scans in people with seronegative AE and SREAT. Utilizing NeuroQ™ software, the Z-scores of 47 brain regions were calculated compared to healthy controls, displayed in heat maps, and visually and statistically compared between study groups and to previous data from NMDA and LGI1 cohorts. <h3>Results:</h3> Sixteen seronegative AE and 4 SREAT patients were identified. All PET scans demonstrated abnormal FDG uptake, while MRI, EEG and CSF were abnormal less frequently in both groups. Both seronegative and SREAT patients demonstrated hypometabolism in the medial frontal, inferior frontal and parieto-temporal regions, and hypermetabolism in the medial temporal lobes. Regions of dysmetabolism were significantly different from NMDA and LGI1 patient data, an effect driven by greater severity of dysmetabolism in the NMDA and LGI1 patients. Follow up scans for 3 seronegative AE patients suggest the degree of dysmetabolism on PET correlates with functional status. <h3>Conclusions:</h3> PET is a useful tool in the evaluation of autoimmune encephalitis. SREAT and seronegative AE represent less differentiated forms of AE. Though frequently abnormal, as anticipated, the pattern of dysmetabolism in SREAT and seronegative AE were less distinct than in NMDA and LGI-1. The pattern of dysmetabolism observed here in SREAT patients was not markedly distinct from seronegative AE patients, potentially supporting consideration of SREAT as a type of seronegative AE rather than a distinct disease entity. <b>Disclosure:</b> Dr. Roman has nothing to disclose. Dr. Sadaghiani has nothing to disclose. Dr. Diaz-Arias has nothing to disclose. Marion Le Marechal has nothing to disclose. Dr. Venkatesan has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Janssen Pharmaceuticals. The institution of Dr. Venkatesan has received research support from NIH. The institution of Dr. Venkatesan has received research support from MSRCF. The institution of Dr. Venkatesan has received research support from U.S. DOD. Dr. Probasco has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for NEJM Journal Watch Neurology.

Identifying mixed Lewy body and Alzheimer’s disease pathologies using functional neuroimaging (P6-12.002)

<h3>Objective:</h3> To distinguish between Alzheimer’s disease, Lewy body dementia and Parkinson’s disease using functional neuroimaging. <h3>Background:</h3> Lewy body dementia (LBD) and Alzheimer’s disease (AD) are the two most common neurodegenerative causes of dementia. Autopsy studies report many cases with these clinical diagnoses having mixed pathology with alpha-synuclein, tau and amyloid proteinopathies. There is limited research in trying to distinguish these potential mixed pathology conditions prior to death. <h3>Design/Methods:</h3> 43 subjects were recruited from Ohio State University Memory Disorder and Movement Clinics. Subjects were diagnosed based on standard clinical criteria for DLB, PD and AD by fellowship trained cognitive and movement disorders faculty. Cognitive testing performed included MMSE and SAGE. We used neuroimaging methods including FDG PET, amyloid PET, and DaTscan SPECT to evaluate subjects diagnosed with dementia with Lewy bodies (DLB), AD and PD to investigate how often potential mixed pathologies could be present. The neuroimaging evaluations were blinded to clinical diagnosis. <h3>Results:</h3> 28 subjects with clinical diagnosis of Lewy body disease (15 DLB and 13 PD) and 15 subjects with clinical diagnosis AD were compared. The Lewy body subjects were 69.5 ± 7.2 years old, MMSE 26.6 ± 4, and SAGE 18.4 ± 4.7. AD subjects were 68.4 ± 9.3 years old, MMSE 16.3 ± 6.4, and SAGE 7.4 ± 6.1. 5 subjects (33%) of the clinical AD cases showed abnormal DAT scan uptake, 3 subjects (20%) of the clinical AD cases were negative for amyloid with normal DaTscan uptake, 3 subjects (20%) of the clinical DLB cases showed mixed LBD and AD features, 2 subjects (13%) of the clinical DLB cases were positive for amyloid with normal DaTscan uptake, and 1 (8%) subject with clinical PD had normal DAT scan. <h3>Conclusions:</h3> Based on functional neuroimaging, 26% of clinically diagnosed AD or DLB subjects had evidence of potential mixed pathologies and 25% were misdiagnosed. <b>Disclosure:</b> Dr. Bouchachi has nothing to disclose. Ms. Truelove has nothing to disclose. Ms. Rawson has nothing to disclose. Mrs. Icenhour has nothing to disclose. Michael Knopp has nothing to disclose. Prof. Wright has a non-compensated relationship as a Board of Directors Member with American Board of Science in Nuclear Medicine that is relevant to AAN interests or activities. Dr. Scharre has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for BrainTest, Inc. Dr. Scharre has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Vascular Scientific. Dr. Scharre has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Acadia. Dr. Scharre has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Scharre has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Acadia. Dr. Scharre has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Biogen. Dr. Scharre has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Hickman &amp; Lowder Co.. The institution of Dr. Scharre has received research support from InSightec. The institution of Dr. Scharre has received research support from Alzheimer’s Therapeutic Research Institute (ATRI). The institution of Dr. Scharre has received research support from Eisai. The institution of Dr. Scharre has received research support from vTv Therapeutics. The institution of Dr. Scharre has received research support from National Institute of Health. The institution of Dr. Scharre has received research support from Eli Lilly. The institution of Dr. Scharre has received research support from Johns Hopkins. The institution of Dr. Scharre has received research support from Biogen. The institution of Dr. Scharre has received research support from Roche. The institution of Dr. Scharre has received research support from AZ Therapies. The institution of Dr. Scharre has received research support from Biohaven. The institution of Dr. Scharre has received research support from Novartis. The institution of Dr. Scharre has received research support from Avanir. The institution of Dr. Scharre has received research support from PrecisionMed, Inc. Dr. Scharre has received intellectual property interests from a discovery or technology relating to health care. Dr. Scharre has received intellectual property interests from a discovery or technology relating to health care.

Can PSMA-Targeting PET/CT Be a Valuable Instrument to Assess the Presence of Brain Metastases in Lung Cancer Patients?: A Case Report.

A 78-year-old man with synchronous diagnosis of prostate cancer and lung adenocarcinoma was referred to our institute for prostate cancer staging with [18F]F-prostate-specific membrane antigen (PSMA) 1007 PET/CT. In addition to the previously known lesion of the right lung, PSMA-targeted PET/CT highlighted 2 areas of abnormal uptake in the brain, in the left frontal and temporal lobes. A subsequent MRI confirmed the lesions observed on PET/CT. Because PSMA-targeting radiopharmaceuticals do not accumulate in healthy brain parenchyma, and recent literature reported promising performances of PSMA-targeted PET/CT in gliomas and metastases from tumors other than prostate cancer, this employment of PSMA radioligands needs to be further explored.

Effectiveness of PET/CT and VATS for detecting and treating internal mammary lymph node metastasis: a case series.

We occasionally observed internal mammary lymph node metastases of breast cancer in a clinical setting. However, unlike a standard treatment in axillary metastasis, surgical resection for internal mammary lymph node metastasis is not prevalent because of unclear safety and benefits. Thus, we aimed to evaluate the diagnostic ability and clinical outcomes of positron emission tomography/computed tomography and video-assisted thoracoscopic surgery. We retrospectively investigated 34 patients with breast cancer with abnormal 18F-fluorodeoxyglucose uptake in internal mammary lymph nodes, at a single centre, between January 2015 and June 2022 and identified 11 female patients (mean age±SD, 51.5±12.9years) who underwent video-assisted thoracoscopic surgery resection. Positron emission tomography/computed tomography was used to determine the clinical stage. We reviewed the surgical pathology of eleven and two patients who underwent direct-view internal mammary lymph node resection to calculate the positive predictive value of positron emission tomography/computed tomography. Ipsilateral fluorodeoxyglucose accumulation was observed, with an average maximum standardized uptake value of 8.9 (range, 3.1-24.0). No perioperative complications occurred, and all patients who underwent video-assisted thoracoscopic surgery alone were discharged from the hospital on post-operative day 2 or 3. The estimated positive predictive value was 80%. All patients were alive, and seven of nine patients with metastasis were relapse-free, at a mean follow-up period of 17.9months (range, 1-51). However, two patients had recurrence at 16 and 14months after surgery for internal mammary lymph node relapse. Radiotherapy is the standard treatment for suspected internal mammary lymph node metastasis detected using positron emission tomography/computed tomography; however, we could safely perform minimally invasive video-assisted thoracoscopic surgery resection, leading to a definite pathological diagnosis.

Abstract 6523: A case of stage I HPV-mediated oropharyngeal squamous cell carcinoma (SCC) diagnosed using a multi-cancer early detection (MCED) test

Abstract There are no routine screening tests for head and neck (H&amp;N) cancers, which account for approximately 4% of all cancers in the US. Risk factors for oropharyngeal cancer include smoking and human papillomavirus (HPV) infection. An MCED test that uses a cell-free DNA-based targeted methylation assay and machine learning classifiers to detect a shared cancer signal and predict the cancer signal origin (CSO) is available as a complement to existing single-cancer screening tests. If a cancer signal is detected, the positive result is reported with 1 or 2 CSO prediction(s). We report here a tonsil cancer case detected using an MCED test and review the CSO-guided diagnostic journey. An asymptomatic 74-year-old White male (BMI: 29.9 kg/m2) with history of chronic lymphocytic leukemia (CLL; Rai stage 0; 13q, CD38, and ZAP-70 negative; no treatment was needed) 17 years prior and papillary thyroid cancer (stage IVa; pT3N1bM0; thyroidectomy and radiation therapy; no recurrence) 8 years prior was screened using the MCED test. Patient had an elevated PSA level (9-10 ng/mL) and was a nonsmoker. Fifteen days after a blood sample was collected for analysis, a positive test result (CSO prediction=H&amp;N) was communicated to the patient (Day 1). PET showed abnormal uptake in the right tonsil (Day 28). The patient was referred for an ENT consult and underwent a right lymph node biopsy (Day 54). The biopsy showed invasive moderately differentiated SCC, non-keratinizing, forming a 3 × 2.1 × 1.2 cm mass (Day 57). Patient underwent right tonsillectomy (the surgical margins were negative for invasive or in situ carcinoma) and lymph node dissection (Day 57). The cancer was diagnosed as HPV-mediated p16+, pT2, pN1, cM0 (stage I) SCC of the oropharynx (Day 57). No chemotherapy or radiation was required due to the early stage of detection. The patient will follow-up with ENT and radiation oncology. The MCED test detected a cancer signal and predicted an accurate CSO for an asymptomatic individual with stage I HPV-mediated oropharyngeal SCC. Notably, despite a history of CLL and an elevated PSA level, the test accurately predicted CSO leading to a directed workup diagnosing asymptomatic cancer in less than 2 months, while the cancer was still at stage I. In the case-control Circulating Cell-free Genome Atlas study, the MCED test sensitivity to detect a cancer signal was 63% in stage I H&amp;N cancer. The use of this MCED test led to detection of cancer in a patient with CLL history and treatment (surgery without complications and without chemotherapy or radiation) with curative intent. Citation Format: Janet Vittone, Julia Feygin, Jason Carey. A case of stage I HPV-mediated oropharyngeal squamous cell carcinoma (SCC) diagnosed using a multi-cancer early detection (MCED) test [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6523.

Insulinoma with equivocal imaging.

A 55-year-old patient was admitted to our department for the management of a repetitive alteration of consciousness. Biological investigation results were consistent with endogenous hyperinsulinemic hypoglycemia. Insulinoma was therefore suspected. Abdominal computed tomography and endoscopic ultrasound showed no obvious pancreatic mass.Somatostatin receptor scintigraphy showed abnormal radioactive uptake in both the pancreatic tail and the uncinate process. Contrariwise, abdominal magnetic resonance imaging showed a unique lesion in the pancreas tail. The patient was then proposed for pancreatic surgery. Both intraoperative manual palpation and intraoperative ultrasonography of the pancreas showed a single corporal lesion of 1.5 cm. No lesion was found in the uncinate process. After a left pancreatectomy, the lesion was histopathologically confirmed to be a well-differentiated neuroendocrine tumor. The symptoms of the patient resolved almost immediately following the surgery. The follow-up is one and a half years to date. The exact preoperative localization of the pancreatic mass remains the most challenging part of insulinoma diagnostic workup. The radiologist's experience is the best warrantor to a precise localization of the tumor. 111In-DTPA-octreotide uptake in the pancreatic uncinate process may be physiological and its interpretation must, therefore, be vigilant. Manual palpation along with intraoperative ultrasonography is considered as the most effective method for the localization of insulinomas during open surgery.

Clinical features of atlantoaxial involvement in patients with rheumatoid arthritis using 18F-fluorodeoxyglucose-positron emission tomography with computed tomography.

Cervical spine involvement is one of the most serious complications in rheumatoid arthritis (RA). The study aim was to assess the clinical significance of atlantoaxial (AA) joint involvement detected by 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) with computed tomography (CT) in patients with RA. A prospective cross-sectional study was conducted to evaluate AA joint involvement detected by FDG-PET/CT in consecutive RA patients from December 2017 to February 2022. We investigated the relationship between AA joint involvement and clinical data, including disease activity and patients' cervical symptoms. Among 48 patients enrolled, abnormal FDG uptake at AA joint was detected in 13 (27%). Rheumatoid factor titre, initial disease activity score 28-erythrocyte sedimentation rate and total standardized uptake value were significantly higher in the 13 patients than in the others (P = 0.004, P < 0.001 and P = 0.001, respectively). All patients with abnormal FDG uptake at AA joint had some cervical symptoms regardless of cervical spine X-ray abnormalities. Neck pain on movement and at rest were more frequent in the 13 patients than in the others (P = 0.001 and P = 0.004, respectively). The most sensitive symptom associated with AA joint involvement was neck pain on movement (sensitivity, 69%), and the most specific symptom was neck pain at rest (specificity, 100%). AA joint involvement was commonly observed by FDG-PET/CT in patients with active RA, independent of radiographic findings. Specific cervical symptoms can be important surrogate markers for detection of potential AA synovitis associated with active RA. Key Points • AA joint involvement was frequently seen in RA with high disease activity independent of radiographic findings. • Neck pain was a hallmark of AA joint involvement reflecting disease activity, and resting pain was highly specific.

FDG PET/CT in Aseptic Splenic Abscess

HomeRadiologyRecently Published PreviousNext Reviews and CommentaryFree AccessImages in RadiologyFDG PET/CT in Aseptic Splenic AbscessWeiting Liu, Xiaohong Ou Weiting Liu, Xiaohong Ou Author AffiliationsFrom the Department of Nuclear Medicine, West China Hospital of Sichuan University, No. 37 Guoxue Alley, Chengdu 610041, People’s Republic of China.Address correspondence to X.O. (email: [email protected]).Weiting LiuXiaohong Ou Published Online:Mar 28 2023https://doi.org/10.1148/radiol.222955MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In A 32-year-old woman presented with fever and arthralgia for 1 month. She had a past medical history of rheumatoid arthritis with 2 years of glucocorticoid treatment. At physical examination, splenomegaly was found. Her laboratory data showed leukocytosis (15.86 × 109/L; reference range, 3.5–9.5 × 109/L) and a high erythrocyte sedimentation rate. Serial blood cultures were negative. Intravenous antibiotics and corticosteroid therapy did not relieve her symptoms. Fluorodeoxyglucose (FDG)-PET/CT examination was performed, showing abnormal standardized uptake values in the spleen (Figure). Primary splenic lymphoma was suspected, and the patient underwent laparoscopic splenectomy. At pathologic examination (Figure), the diagnosis of aseptic splenic abscesses as a complication of rheumatoid arthritis was made. Corticosteroids and supportive treatment were then initiated, and her clinical condition gradually improved.Images in a 32-year-old woman presenting with fever and arthralgia for 1 month. She had a past medical history of rheumatoid arthritis with 2 years of glucocorticoid treatment. A fluorodeoxyglucose (FDG)-PET examination was performed. (A) Maximum intensity projection whole body image shows intense diffuse splenic uptake and moderate bone marrow uptake. (B) Axial-fused PET/CT abdominal image shows an enlarged spleen with heterogeneously increased FDG standardized maximum uptake value (standardized maximum uptake value,13.94; liver standardized maximum uptake value, 3.76). At pathologic examination, macroscopic examination of the spleen showed many nonconfluent white nodules (not shown). (C) With use of hematoxylin and eosin, a photomicrograph with 400× magnification shows numerous areas of necrosis surrounded by intense polymorphonuclear cell infiltration (arrows) and fibroblastic proliferation at the periphery of the splenic nodules.Download as PowerPointOpen in Image Viewer Splenic abscesses generally occur in patients with immune dysfunction (1), presenting as solitary or multifocal lesions. Aseptic abscesses are most commonly associated with nonspecific inflammatory bowel disease and other autoimmune diseases (spondyloarthropathy, rheumatoid arthritis, lupus erythematosus, and nodular arteritis), or autoinflammatory (synovitis, acne, pustulosis, hyperostosis, and osteitis) and neoplastic ones (myeloma, monoclonal gammopathy) (2). Histopathologic examination helps to exclude other conditions. The cornerstones of aseptic abscesses are mature polymorphonuclear neutrophils in the center of the splenic nodules, with histiocytes and single giant cells present at the periphery (2). It is unclear whether glucocorticoids could be a factor that promotes the formation of aseptic splenic abscesses. The presence of disseminated sterile splenic microabscesses with intense FDG uptake related to rheumatoid arthritis is rare.Disclosures of conflicts of interest: W.L. No relevant relationships. X.O. No relevant relationships.

A case of middle-aged male with multicentric solid pseudopapillary neoplasm of the pancreas.

Solid pseudopapillary neoplasm (SPN) of the pancreas is a low-grade, malignant pancreatic tumor that occurs predominantly in young females. In this report, an extremely rare case of multicentric SPNs in a middle-aged male is discussed. A 55-year-old man was incidentally found to have a mass in the pancreatic body on abdominal ultrasonography during a medical checkup. Contrast-enhanced computed tomography (CT) revealed masses with 50-mm and 25-mm diameters with internal calcification in the pancreatic body and tail, respectively. These masses had a gradually increasing enhancement pattern though the center of the pancreatic body mass and the periphery of the pancreatic tail lesion were non-enhancing. Magnetic resonance imaging revealed a hyperintense signal in the mass of the pancreatic tail suggestive of hemorrhage on T1-weighted imaging. Positron emission tomography-CT revealed abnormal uptake of fluorodeoxyglucose in both lesions. Endoscopic ultrasound-guided fine needle aspiration was performed on both lesions, and tumor tissue with a solid proliferation of poorly pleomorphic small cells was observed. The tumor cells were positive for CD10 in the cytoplasm and β-catenin in the nucleus. The patient was diagnosed with SPNs and underwent a successful distal pancreatectomy.

Quantitative assessment of 99mTc-methylene diphosphonate bone SPECT/CT for assessing bone metastatic burden and its prognostic value in patients with castration-resistant prostate cancers: initial results in a single-center retrospective study

To evaluate the prognostic value of the quantitative assessment of 99mTc-methylene diphosphonate (99mTc-MDP) bone SPECT/CT in castration-resistant prostate cancer (CRPC) patients with bone metastases. A total of 103 patients who underwent 99mTc-MDP bone SPECT/CT imaging from the neck to the proximal femur were included. First, in 65 patients without bone metastases, the normal range of standardized uptake value (SUV) of non-pathological bone was evaluated to determine an SUV threshold to reliably exclude most normal osseous activity. Then, in 38 CRPC patients with bone metastases, lesion uptake volume (LUV), which is the extracted volume of bone metastases exhibiting high accumulation above the SUV threshold, was calculated. The relation between LUV and prostate-related mortality was statistically evaluated. Based on the SUV measurements of non-pathological bones, the optimal SUV threshold, which defines abnormal bone SPECT uptake, was determined to be 8. Median LUV was 39mL (interquartile range 4.0-104.3mL) in the CRPC subjects with bone metastases. Kaplan-Meier survival analysis showed a significant relation between prostate cancer-specific survival and LUV (cut-off value, 19.95mL; P = 0.001). Multivariate analysis revealed LUV as an independent prognostic factor for the survival (P = 0.008, hazard ratio 23.424). Global chi-square test showed that LUV had significant incremental prognostic value in addition to prostate-specific antigen and the interval from progression to CRPC until bone SPECT/CT (P = 0.022). Quantitative assessment of 99mTc-MDP bone SPECT images can provide valuable prognostic information in CRPC patients with bone metastases.

Prospective Pilot Study of 18F-Fluoroestradiol PET/CT in Patients With Invasive Lobular Carcinomas.

BACKGROUND. PET/CT with 18F-fluoroestradiol (FES) (FDA-approved in 2020) depicts tissues expressing estrogen receptor (ER). Invasive lobular carcinoma (ILC) is commonly ER positive. OBJECTIVE. The primary aim of this study was to assess the frequency with which sites of histologically proven ILC have abnormal uptake on FES PET/CT. METHODS. This prospective single-center pilot study, conducted from December 2020 to August 2021, enrolled patients with histologically confirmed ILC to undergo FES PET/CT; patients optionally underwent FDG PET/CT. Two nuclear radiologists assessed FES PET/CT and FDG PET/CT studies for abnormal uptake corresponding to known ILC sites at enrollment and for additional sites of abnormal uptake, resolving differences by consensus. The primary endpoint was percentage of known ILC sites showing abnormal FES uptake. The alternative to the null hypothesis was that more than 60% of sites would have abnormal FES uptake, exceeding the percentage of ILC with abnormal FDG uptake described in prior literature. A sample size of 24 biopsied lesions was preselected to provide 81% power for the alternative hypothesis (one-sided α = .10). Findings on FES PET/CT and FDG PET/CT were summarized for additional secondary endpoints. RESULTS. The final analysis included 17 patients (mean age, 59.1 ± 13.2 years) with 25 sites of histologically confirmed ILC at enrollment (22 breast lesions, two axillary lymph nodes, one distant metastasis). FES PET/CT showed abnormal uptake in 22 of 25 (88%) lesions, sufficient to reject the null hypothesis (p = .002). Thirteen patients underwent FDG PET/CT. Four of 23 (17%) sites of histologically confirmed ILC, including additional sites detected and confirmed after enrollment, were identified with FES PET/CT only, and 1 of 23 (4%) was identified only with FDG PET/CT (p = .18). FES PET/CT depicted additional lesions not detected with standard-of-care evaluation in 4 of 17 (24%) patients (two contralateral breast cancers and two metastatic axillary lymph nodes, all with subsequent histologic confirmation). Use of FES PET/CT resulted in changes in clinical stage with respect to standard-of-care evaluation in 3 of 17 (18%) patients. CONCLUSION. The primary endpoint of the trial was met. The frequency of abnormal FES uptake among sites of histologically known ILC was found to be to be significantly greater than 60%. CLINICAL IMPACT. This pilot study shows a potential role of FES PET/CT in evaluation of patients with ILC. TRIAL REGISTRATION. ClinicalTrials.gov NCT04252859.

Clinicopathological associations of hemispheric dominance in primary progressive apraxia of speech.

Primary progressive apraxia of speech (PPAOS) is associated with imaging abnormalities in the lateral premotor cortex (LPC) and supplementary motor area (SMA). It is not known whether greater involvement of these regions in either hemisphere is associated with demographics, presenting, and/or longitudinal features. In 51 prospectively recruited PPAOS patients who completed [18 F]-fluorodeoxyglucose (FDG) positron emission tomography (PET), we classified patients as left-dominant, right-dominant, or symmetric, based on visual assessment of the LPC and SMA on FDG-PET. SPM and statistical analyses of regional metabolic values were performed. Diagnosis of PPAOS was made if apraxia of speech was present and aphasia absent. Thirteen patients completed ioflupane-123I (dopamine transporter [DAT]) scans. We compared cross-sectional and longitudinal clinicopathological, genetic, and neuroimaging characteristics across the three groups, with area under the receiver-operating curve (AUROC) determined as a measure of effect size. In all, 49% of the PPAOS patients were classified as left-dominant, 31% as right-dominant, and 20% as symmetric, which was supported by results from the SPM and regional analyses. There were no differences in baseline characteristics. Longitudinally, right-dominant PPAOS showed faster rates of progression of ideomotor apraxia (AUROC0.79), behavioral disturbances (AUROC 0.84), including disinhibition symptoms (AUROC0.82) and negative behaviors (AUROC 0.82), and parkinsonism (AUROC 0.75) compared to left-dominant PPAOS. Symmetric PPAOS showed faster rates of dysarthria progression compared to left-dominant (AUROC 0.89) and right-dominant PPAOS (AUROC 0.79). Five patients showed abnormal DAT uptake. Braak neurofibrillary tangle stage differed across groups (p=0.01). Patients with PPAOS and a right-dominant pattern of hypometabolism on FDG-PET have the fastest rates of decline of behavioral and motor features.

Bayesian penalized likelihood PET reconstruction impact on quantitative metrics in diffuse large B-cell lymphoma.

Evaluate the quantitative, subjective (Deauville score [DS]) and reader agreement differences between standard ordered subset expectation maximization (OSEM) and Bayesian penalized likelihood (BPL) positron emission tomography (PET) reconstruction methods. A retrospective review of 104 F-18 fluorodeoxyglucose PET/computed tomography (CT) exams among 52 patients with diffuse large B-cell lymphoma. An unblinded radiologist moderator reviewed both BPL and OSEM PET/CT exams. Four blinded radiologists then reviewed the annotated cases to provide a visual DS for each annotated lesion. Significant (P < .001) differences in BPL and OSEM PET methods were identified with greater standard uptake value (SUV) maximum and SUV mean for BPL. The DS was altered in 25% of cases when BPL and OSEM were reviewed by the same radiologist. Interobserver DS agreement was higher for OSEM (>1 cm lesion = 0.89 and ≤1 cm lesion = 0.84) compared to BPL (>1 cm lesion = 0.85 and ≤1 cm lesion = 0.81). Among the 4 readers, average intraobserver visual DS agreement between OSEM and BPL was 0.67 for lesions >1cm and 0.4 for lesions ≤1 cm. F-18 Fluorodeoxyglucose PET/CT of diffuse large B-cell lymphoma reconstructed with BPL has higher SUV values, altered DSs and reader agreement when compared to OSEM. This report finds volumetric PET measurements such as metabolic tumor volume to be similar between BPL and OSEM PET reconstructions. Efforts such as adoption of European Association Research Ltd accreditation should be made to harmonize PET data with an aim at balancing the need for harmonization and sensitivity for lesion detection.

Role of [18F] FDG PET-CT in detection of COVID-19 vaccine-associated hypermetabolic lymphadenopathy (VAHL) in lymphoma patients: with serologic testing correlation

BackgroundCOVID-19 vaccination of the population has a great importance, especially in oncological patients. The high incidence of vaccine-associated hypermetabolic lymphadenopathy (VAHL) makes a difficulty in the diagnosis of PET-CT of oncological patients. They should be vaccinated in the side opposite to the expected malignant LNs to avoid unnecessary biopsy and change in therapy. The aim of this study was to assess the role of PET-CT in detection of VAHL after the 2nd dose of Pfizer-BioNTech vaccine in lymphoma patients and compare the incidence of VAHL among lymphoma patients treated with B cell depletion therapy during the 6 months prior to vaccination and those treated > 6 months before vaccination.ResultsThis study comprised 120 lymphoma patients, referred for FDG PET/CT 1–3 weeks after the 2nd dose of Pfizer-BioNTech COVID-19 vaccine. Hypermetabolic LNs were identified in 55%. The incidence of VAHL in lymphoma patients treated with anti-CD20 antibody rituximab during the 6 months prior to vaccination (9%) was significantly lower compared with other lymphoma patients treated with anti-CD20 antibody rituximab > 6 months before vaccination (91%). The incidence and grades of VAHL are significantly high within the 1st week after the 2nd dose of Pfizer-BioNTech vaccine in patients younger than 60 years of age. Only 7 of 37 patients with negative serology had VAHL on PET-CT, whereas 10 of 26 patients with decreased anti-spike titers and 49 of 57 patients with increased anti-spike titers had VAHL on PET-CT.ConclusionsVAHL makes challenges in the interpretation of FDG PET/CT in oncology patients. Accurate data collection, regarding the time and site of COVID vaccination, is important to help radiologists in identifying the cause of abnormal nodal FDG uptake. We suggest to schedule FDG PET-CT for lymphoma patients at least 3 weeks after the 2nd dose of Pfizer-BioNTech vaccine.

Visualization of tumor hypoxia and re-oxygenation after stereotactic body radiation therapy in early peripheral lung cancer: A prospective study

Background and purposeIn this study, fluoromisonidazole positron emission tomography (F-MISO PET/CT) was used to evaluate tumor hypoxia and re-oxygenation in patients with lung tumors treated with stereotactic body radiation therapy (SBRT). Materials and methodsPatients with T1-2 N0 lung cancer were included in this study. The prescribed dose was 48–52 Gy in four fractions. F-MISO PET/CT was performed twice, before SBRT and 1–3 days after the first irradiation. The maximum standardized uptake value (SUVmax) and tumor/muscle ratio (TMR) were evaluated as indicators of hypoxia. The threshold for hypoxia was defined as a TMR of 1.30 or more. ResultsBetween 2016 and 2021, 15 patients were included. Pre-treatment tumor hypoxia was observed in nine tumors (60 %). TMR in all six tumors without pre-treatment hypoxia rose after single high-dose irradiation. In contrast, TMR in six of nine tumors with pre-treatment hypoxia dropped after irradiation, suggesting re-oxygenation. Although no local recurrence was noted, regional and/or distant relapses were seen in four patients (27 %). Of these, three had tumors with abnormal F-MISO uptake. The remaining patient had a tumor without signs of hypoxia on pre-treatment PET/CT. The 2-year progression free survival of patients with tumors with and without pre-treatment hypoxia were 30 % and 63 %, respectively (p = 0.319). ConclusionTumor hypoxia reduced after single high-dose irradiation. Tumor with F-MISO uptake seems to be an unfavorable prognostic factor in lung SBRT.

Emerging PET Tracers in Cardiac Molecular Imaging.

18F-fluorodeoxyglucose (FDG) and 18F-sodium fluoride (NaF) represent emerging PET tracers used to assess atherosclerosis-related inflammation and molecular calcification, respectively. By localizing to sites with high glucose utilization, FDG has been used to assess myocardial viability for decades, and its role in evaluating cardiac sarcoidosis has come to represent a major application. In addition to determining late-stage changes such as loss of perfusion or viability, by targeting mechanisms present in atherosclerosis, PET-based techniques have the ability to characterize atherogenesis in the early stages to guide intervention. Although it was once thought that FDG would be a reliable indicator of ongoing plaque formation, micro-calcification as portrayed by NaF-PET/CT appears to be a superior method of monitoring disease progression. PET imaging with NaF has the additional advantage of being able to determine abnormal uptake due to coronary artery disease, which is obscured by physiologic myocardial activity on FDG-PET/CT. In this review, we discuss the evolving roles of FDG, NaF, and other PET tracers in cardiac molecular imaging.