FDG PET-CT Research Articles

FDG PET-CT missed tibial metastasis in head and neck cancer, case report and systematic review

FDG PET-CT missed tibial metastasis in head and neck cancer, case report and systematic review

CT radiation dose reduction with tin filter for localisation/characterisation level image quality in PET-CT: a phantom study

BackgroundThe tin filter has allowed radiation dose reduction in some standalone diagnostic computed tomography (CT) applications. Yet, ‘low-dose’ CT scans are commonly used in positron emission tomography (PET)-CT for lesion localisation/characterisation (L/C), with higher noise tolerated. Thus, dose reductions permissible with the tin filter at this image quality level may differ. The aim was to determine the level of CT dose reduction permitted with the tin filter in PET-CT, for comparable image quality to the clinical reference standard (CRS) L/C CT images acquired with standard filtration.Materials and methodsA whole-body CT phantom was scanned with standard filtration in CRS protocols, using 120 kV with 20mAs-ref for bone L/C (used in 18F-Sodium Fluoride (NaF) PET-CT) and 40mAs-ref for soft tissue L/C (used in 18F-Fluorodeoxyglucose (FDG) PET-CT), followed by tin filter scans at 100 kV (Sn100kV) and 140 kV (Sn140kV) with a range of mAs settings. For each scan, effective dose (ED) in an equivalent-sized patient was calculated, and image quality determined in 5 different tissues through quantitative (contrast-to-noise ratio) and qualitative (visual) analyses. The relative dose reductions which could be achieved with the tin filter for comparable image quality to CRS images were calculated.ResultsQuantitative analysis demonstrated dose savings of 50–76% in bone, 27–51% in lung and 8–61% in soft tissue with use of the tin filter at Sn100kV. Qualitative analysis demonstrated dose reductions using Sn100kV in general agreement with the dose reductions indicated by quantitative analysis. Overall, CT dose reductions of around 85% were indicated for NaF bone PET-CT, allowing whole-body CT at just 0.2mSv ED, and a 30–40% CT dose reduction for FDG PET-CT using Sn100kV (1.7-2.0mSv), providing comparable image quality to current CRS images with standard filtration. Sn140kV demonstrated limited value in CT dose reduction.ConclusionsLarge CT dose reductions can be made using the tin filter at Sn100kV, when imaging bone, lung and soft tissue at L/C level CT image quality in PET-CT. As well as reducing the risk of inducing a cancer in later life, such dose reductions may also impact PET-CT practice, such as justifying cross-sectional over planar imaging or justifying PET-CT in younger patients.

[18F]FDG PET/CT performs better than CT in determining the bone biopsy site : randomized controlled clinical trial

BackgroundBone biopsy is the gold standard for diagnosing bone metastases. However, there is no clinical consensus regarding the optimal imaging test for determining the puncture site.MethodsWe compared the performance of [18F]FDG PET/CT with CT in detecting bone metastases to achieve the highest biopsy efficiency. This registered prospective study enrolled 273 patients with bone lesions who were treated between January 2020 and March 2021. Patients were randomly assigned to undergo [18F]FDG PET/CT or CT to determine the puncture site before bone biopsy. The accuracy, sensitivity, specificity, second biopsy rate, diagnostic time and cost-effectiveness of the two imaging tests were compared.ResultsThe accuracy and sensitivity of [18F]FDG PET/CT group in detecting bone metastases were significantly higher than CT group(97.08% vs. 90.44%, 98.76% vs. 92.22%, P < 0.05). The second biopsy rate was significantly lower in the [18F]FDG PET/CT group (2.19% vs. 5.15%; P < 0.05). The diagnostic time of [18F]FDG PET/CT was 18.33 ± 2.08 days, which was significantly shorter than 21.28 ± 1.25 days in CT group ( P < 0.05). The cost of [18F] FDG PETCT is 11428.35 yuan, and the cost of CT is 13287.52 yuan; the incremental cost is 1859.17 yuan. SUVmax > 6.3 combined with ALP > 103 U/L showed a tendency for tumor metastases with an AUC of 0.901 (95%CI 0.839 to 0.946, P < 0.001).Conclusion[18F]FDG PET/CT has better performance and cost-effectiveness than CT in determining the bone biopsy site for suspect bone metastases.Trial registrationThe prospective study was registered on 2018-04-10, and the registration number is ChiCTR1800015540.

166Ho-RadioEmbolizaTiOn Using personalized prediCtive dosimetry in patients with Hepatocellular carcinoma: A prospective, single-centre study (RETOUCH).

Holmium-166 (166Ho) radioembolization could offer a more individualized approach in terms of imaging and dosimetry. We aim to evaluate the feasibility and safety of 166Ho selective internal radiation therapy (SIRT) using a higher tumour dose than previously administered determined by 166Ho-scout as a surrogate marker in HCC patients. This is an open-label, prospective, non-randomized, single-centre pilot study that included patients with HCC that received 166Ho-SIRT if the work-up using 166Ho-scout showed a tumour-absorbed dose ≥150 Gy, a non-tumoural liver absorbed dose less than 60 Gy and a lung absorbed dose less than 30 Gy. Primary endpoints were feasibility and safety-toxicity profiles at 24-48 h and 1 month. Overall response rates (ORR) at 3 months (mRECIST, RECIST 1.1 and metabolic response by FDG and choline PET CT) and time to progression (TTP) represented the secondary endpoints. Fifteen patients with large tumours (mean diameter 55.67 ± 28.42 mm) received 17 166Ho-SIRT treatments between July 2020 and June 2022. All the attempted treatments were accomplished. Mean administered tumour dose was 183.18 ± 71.71 Gy, while non-tumour liver dose was 30.29 ± 14.56 Gy. Median time of follow-up was 12 months (IQR 9-16). Only grade 1-2 clinical and biological AEs were observed. There were no liver decompensations. At 3 months, objective response was achieved for all target lesions (CR 78.57%, PR 21.43% according to mRECIST). Median TTP was 18.8 (range 2.9; n.e.) months. Personalized 166Ho-SIRT with a tumour delivered dose ≥150 Gy was feasible and safe for HCC patients with promising response rates.

Abstract 4119267: Diagnosing An Uncommon Presentation of Cardiac Sarcoidosis with Isolated Bi-Atrial Involvement: A Case Report

Background: Sarcoidosis, a systemic granulomatous inflammatory disorder can involve various organs, including the heart but isolated bi-atrial cardiac involvement is rare. Advanced cardiac imaging especially in atypical presentations, can aid in early diagnosis. Case: A 59 year-old man with history of biopsy-proven pulmonary sarcoidosis presented with non exertional chest pain for 2 months. EKG, cardiac enzymes, and Initial echocardiogram(TTE) was unremarkable. Stress echocardiogram ruled out myocardial ischemia. CT scan noted mediastinal lymphadenopathy consistent with known sarcidosis. In absence of other explainable etiolgies for chest pain, Cardiac MRI was done and showed preserved biventricular function, subepicardial enhancement in the basal inferior, inferolateral, and anterolateral walls. The enhancement raised suspicion for CS. However, symptoms resolved spontaneously, cardiac workup paused and he was monitored conservatively with serial Echocardiogram(TTE) until onset of dyspnea 3 years later. Repeat TTE and EKG then noted newly enlarged left atrium and atrial tachycardia. Further testing with Cardiac positron emission tomographic imaging with F-18 fluorodeoxyglucose (FDG-PET CT) showed abnormal myocardial uptake in both atrial posterior walls but no ventricular involvement, indicative of isolated bi-atrial inflammation in CS. He was treated with prednisone and methotrexate. Successful symptom and inflammation resolution on FDG-PET CT occurred in 3 months Discussion: CS is rare and seen clinically in about 5% and diagnosed postmortem in 25% of sarcoidosis cases. Symptoms vary widely, with potential for severe heart complications. Left ventricle and interventricular septum are commonly involved, but isolated bi-atrial involvement is rare. Early diagnosis aided by Cardiac MRI and FDG-PET CT is crucial. Prednisone is mainstay of treatment, often combined with methotrexate. Cases of concurrent atrial CS involvement and bi-atrial fibrosis with Left ventricular hyperenhancement are documented, but this is the first known report of isolated bi-atrial hyperenhancement on FDG-PET CT for CS. This case highlights the need for symptom correlation with clinical and imaging follow-up, especially in atypical presentations.

Abstract 4138717: Infective Root Aortitis: Medical Therapy Alone or Medical Therapy and Surgery?

Clinical presentation: A 75-year-old male with previous 3 vessel CABG and bioprosthetic aortic valve (BAV) surgical replacement in 2013 was admitted with severe sepsis from diabetic foot ulcer complicated with Group A Streptococcus bacteremia and infective root aortitis. Imaging Findings: Initial technically limited transthoracic echocardiogram was followed by a transesophageal echocardiogram (TEE) that demonstrated a well seated BAV with mildly thickened leaflets but no vegetations, mild intra-valvular regurgitation, and 9 mm end-diastolic soft tissue echoreflectant thickening of the posterior aortic root (AoR) extending up 3 cm from the aortic annulus to the ascending aorta (Fig 1A,B). There were no signs of perivalvular abscess formation. Initial FDG PET-CT demonstrated heterogenous hypermetabolic activity at the annulus of the BAV (Fig 1C) and AoR (Fig 1D) consistent with aortitis. Decision-making: In the absence of guidelines for the management of these patients, a multidisciplinary team including cardiology, cardiothoracic surgery, and infectious disease opted for a conservative medical therapy instead of high-risk surgery. Patient then underwent left foot first digit amputation to achieve infectious source control. Upon completion of 4 out of 6 weeks of intravenous ceftriaxone 2 grams daily, repeat TEE showed improved AoR thickening to 6 mm (Fig 1E,F), no AoR abscess, and unchanged BAV structure and function. Repeat FDG PET-CT at the same time of TEE demonstrated persistent but improved hypermetabolic activity of the BAV annulus and AoR. After 10 weeks of IV antibiotics, repeat FDG PET-CT showed further decrease in metabolic activity on both areas. However, an Indium-111 labeled leukocyte scan showed no activity at the BAV annulus and root (Fig 1G) and therefore indicated healed AoR aortitis, which was further supported by significant decrease of ESR and CRP initial values of 126 mm/hr and 122.7 mg/L to 11 mm/hr and 3 mg/L, respectively. Patient is currently clinically stable 8 months later. Conclusion: This case illustrates that a conservative management of infective AoR aortitis with an extended course of intravenous antibiotics is a reasonable alternative to high-risk re-do valve and root surgery.

CTR-FAPI PET enables precision management of medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC) can only be cured through the excision of all metastatic lesions, but 29-60% patients failed to localize the disease in the current clinical practice. Previously, we developed a fibroblast activation protein inhibitor (FAPI)-based covalent targeted radioligand (CTR) for improved detection sensitivity and accuracy. In this first-in-class clinical trial, we head-to-head compared [68Ga]Ga-CTR-FAPI PET-CT and [18F]FDG PET-CT in 50 MTC patients. The primary endpoint was the patient-based detection rate, with [68Ga]Ga-CTR-FAPI exhibiting higher detection than [18F]FDG (98% vs. 66%, p=0.0002). This improved detection was attributed to increased tumor uptake (SUVmax 11.71±9.16 vs. 2.55±1.73, p<0.0001). Diagnostic accuracy, validated on lesions with gold-standard pathology, was greater for [68Ga]Ga-CTR-FAPI compared to [18F]FDG (96.7% vs. 43.3%, p<0.0001). Notably, 32% patients altered management following [68Ga]Ga-CTR-FAPI PET-CT, and 66.7% patients changed their surgical plan. Overall, [68Ga]Ga-CTR-FAPI PET-CT provided superior detection and diagnostic accuracy compared to [18F]FDG PET-CT, enabling precision management of MTC patients.

7246 Cardiac Paraganglioma: A Rare Entity

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

Bilan d’extension du cancer bronchique

The management of lung cancer patients requires a definitive diagnosis and a precise assessment of the disease extent. Pathological examination performed on tissue or cytological samples taken from the tumor, associated lymphadenopathy or an accessible metastatic site answers the first question while a set of staging techniques ensures the second. Guidelines for each technique have been issued in order to maximize diagnostic yield and allow immunohistochemical and molecular biology analyzes which impact the therapeutic strategy. The aim of this article is to discuss the different diagnostic and staging methods and to propose solutions for optimizing the diagnosis and the assessment of the anatomic extent of lung cancers. In this context, the indications and limits of the different modalities are discussed. The size of the tumor, its pleural, parietal, endobronchial and direct mediastinal extension must be specified as well as lymph node and distant extension. The clinical examination remains essential. Contrast enhanced Chest CT is systematic, unless contraindicated. 18FDG PET-CT is not always indicated but is essential in patients potentially eligible for curative treatment. Brain imaging is indicated, even in asymptomatic patients. Compliance with recommendations and adequate organization optimize patient care.1877-1203/© 2024 SPLF. Published by Elsevier Masson SAS. All rights reserved.

PET/CT Response Assessment in Pediatric Hodgkin Lymphoma: Does Deauville Score 3 Reflect Negativity?

FDG PET is required for the staging and response evaluation of pediatric Hodgkin lymphoma. This study aimed to evaluate the outcomes of pediatric patients with Hodgkin's lymphoma based on interim PET CT assessments of early response following second-cycle chemotherapy using the Deauville score (DS). It also determines whether DS-3 is providing an adequate or inadequate response. We conducted a retrospective cohort study including 504 pediatric patients with classic Hodgkin lymphoma who were treated with chemotherapy based on the Euro-Net protocol at the Children Cancer Hospital Egypt from March 2019 till the end of October 2022. Patients with adequate response DS 1/2 and DS 3 showed nearly the same 3-year event-free survival (EFS) of 91.9% and 91.5%, respectively, compared with those patients with inadequate response DS 4/5, who showed an EFS of 80.4% ( P =0.001). Patients with a DS 3 at interim PET evaluation were considered negative as DS 1/2. Patients of DS 3 group who did not receive radiotherapy had a much worse 3-year EFS by the existence of positive B symptoms, an ESR>30, or an advanced stage. Radiation therapy did not improve the 3-year EFS in patients with an inadequate response (DS4/5) and poor prognostic characteristics. They still need more advanced treatment. DS 1/2 and DS 3 had about the same 3-year EFS, which is better than the 3-year EFS of patients with DS 4/5. Therefore, we can classify DS 3 as having negative FDG PET CT uptake.

460. THE ADDITIONAL VALUE OF CERVICAL ULTRASOUND IN THE DETECTION OF CERVICAL LYMPH NODE METASTASES IN PATIENTS WITH ESOPHAGEAL CANCER

Abstract Background Esophageal cancer patients with cervical lymph node metastases, staged according to the 8th edition of the American Joint Committee on Cancer (AJCC), are considered to have stage IV disease and are generally not eligible for treatment with curative intent. External cervical ultrasound (US) used to be standard in the diagnostic workup for detection of cervical lymph node metastases in the Netherlands, but is no longer included in the esophageal cancer guideline. This study aimed to assess the additional value of US over 18FDG PET-CT for the detection of cervical lymph node metastases in esophageal cancer patients, to reassure justified removal of cervical US from the guideline. Methods This retrospective cohort study included all esophageal cancer patients referred to or diagnosed in the Amsterdam UMC between January 2014 and January 2021. Radiology and multidisciplinary team meeting reports were reviewed to identify patients with suspected cervical lymph node(s). Primary outcome was detection rate of cervical lymph node metastases on ultrasound and/or 18FDG PET-CT. Golden standard was etiology based on Fine Needle Aspiration (FNA). Results This study included 768 patients, with a median age of 66 years. Patients were predominantly male (75.0%) and the majority had an adenocarcinoma (71.9%). On 18FDG PET-CT, 77 patients had suspected cervical lymph nodes. Of those, 39 proved malignant. Seven malignant lymph nodes were missed on 18FDG PET-CT. 18FDG PET-CT had a positive predictive value (PPV) of 50.6%, a negative predictive value (NPV) of 99.0%, a sensitivity of 84.8% and a specificity of 94.7%. Based on US alone, 134 patients had suspected cervical lymph nodes. Of those, 45 proved malignant. One malignant lymph node was missed on US. US had a PVV of 33.6%, a NPV of 99.8%, a sensitivity of 97.8% and a specificity of 87.7%. In total, suspected cervical lymph nodes were documented in 151 patients (19.7%). FNA was conducted in 134 out of 151 patients. Of those, 46 proved malignant. No major complications after FNA were reported. For 21 patients, this resulted in stage migration and changed policy from curative intent to palliative. Conclusion Standard US increases the number of FNA conducted for benign cervical lymph nodes, as the positive predictive value is low (33.6%). However, it does have an additional value as it identifies 15% of cervical lymph node metastases that were not seen on 18FDG PET-CT.

FDG PET-CT for the Detection of Occult Nodal Metastases in Head and Neck Cancer: A Systematic Review and Meta-Analysis.

Because of an estimated 20-30% prevalence of occult lymph node (LN) metastases in patients with head and neck squamous cell carcinoma (HNSCC), neck dissection is often proposed, despite its potential morbidity. In this systematic review and meta-analysis, the diagnostic performance of FDG PET-CT in detecting occult LN metastases was evaluated in patients with clinically negative necks (cN0) and in whom histopathology of a neck dissection specimen served as gold standard. Overall, 16 studies out of 2062 screened on PubMed and EMBASE fulfilled the inclusion criteria (n = 1148 patients). Seven of these sixteen studies were split into two or three studies because they contained data that could be processed distinctly in our meta-analysis. For this reason, a total of 25 studies were identified and included in the analysis (n total = 1918 patients). The overall prevalence of metastatic nodes per patient was 22.67%. The pooled sensitivity, specificity, diagnostic odds ratios, and negative predictive value (NPV) were 0.71 (95%CI: 0.66-0.75), 0.90 (95%CI: 0.84-0.93), 20.03 (95%CI: 13.51-29.70), and 0.92 (95%CI: 0.89-0.95), respectively. The main causes of inter-study heterogeneity included different reference standards (evaluation per patient, per neck side, or per neck level). The current meta-analysis showed that FDG PET-CT has a high specificity and NPV for ruling out nodal involvement in cN0 necks, but a limited sensitivity.

Role of the FDG PET CT Scan in Pretreatment Evaluation of Oral Carcinomas.

Pre-treatment role of FDG PET CT scan to evaluate- the extent of the primary lesion, nodal staging and distant metastasis in oral carcinoma in various TNM stages. Additionally, our study investigated the Correlation between SUVmax values on FDG-PET CT scans and histopathological proven positive nodes in patients undergoing surgery. In this study, all suspected cases of oral carcinoma in adults who visited the ENT clinic were examined and evaluated using various methods, including clinical examination, cytology, histopathology, and imaging tests like CECT scans, ultrasound, and CEMRI. Based on the results of these evaluations, the patients were staged. The patients were then given FDG-PET CT scans (done within 2weeks of CECT/MRI scans), for restaging and treatment plans, such as surgery, chemotherapy, radiotherapy, or a combination of these methods, were developed. After surgery, the patients were restaged based on the histopathology report, and the results of the FDG-PET CT scans were compared to the histopathological findings and the histopathological positive nodes were compared to the SUV max value on the FDG PET CT scan and were correlated. In our study, the mean age of patients was found to be 50years with a male: female ratio of 3.5:1. Maximum tumors presented at the buccal mucosa region. 92% of patients gave a history of tobacco addiction, and 18% were smokers. As per initial biopsy reports, maximum (62%) tumors were detected to be WDSCC, 2% were MDSCC and 6% were PDSCC. All 50 patients had normal findings on the chest x-ray and USG abdomen. 41 patients underwent CECT scans and 9 patients got CEMRI scans done. Staging after FDG PET CT scan was compared with that of radiological staging. It was found that in T staging there was upstaging in 36% of cases and downstaging in 14% of cases following the FDG PET CT scan. Likewise, N staging showed upstaging in 36% of cases and downstaging in 16% of cases after the FDG PET CT scan. In M staging, there was upstaging in 10% of cases after the FDG PET CT scan. In our study 15 cases got operated on. All 8 (53.3%) cases of postoperative histopathological positive lymph nodes had SUV max values greater than their reference value (> 2.5), and all negative histopathological lymph nodes had a low SUV max (< 2.5) value in the PET CT scan. The FDG PET CT scan is a highly effective tool for accurately diagnosing, staging, and predicting the outcome of oral cancers at all stages of the disease. The SUV max value (> 2.5) of the PET CT scan is positively correlated with the likelihood of nodal metastasis, as higher values were found to correspond with histopathological evidence of positive neck nodes.

Utility of PET-CT for assessment of response to neo-adjuvant chemotherapy in breast cancer.

12 Background: Response to neo-adjuvant chemotherapy (NACT) is associated with prognosis in non-metastatic breast cancer and can potentially inform further therapeutic options. The aim of this study was to correlate post NACT response on PET CT with pathological response. Methods: All patients who underwent pre- NACT (baseline) and post NACT PET CT imaging with F-18 FDG in a dose of 5-7 MBq/kg body weight with a minimum of 185 MBq given intravenously were retrospectively analyzed. Scan was performed on GE Discovery 710 whole-body PET scan with 128 slice CT. Relevant clinical and imaging related details were extracted from the treatment records. Post NACT PET response (PERCIST criteria) in the primary tumor and nodes was correlated with the pathological response on the post surgical specimen. Analysis was done using Microsoft Excel and SPSS v20 (IBM SPSS). Results: The median age was 49 years (range 30-76 years). 83.1% of patients had node positive disease on baseline PET imaging (not pathologically confirmed). Post chemotherapy PET showed complete metabolic response in the primary tumor and regional nodes in 56.3% and 74% of patients respectively. Two patients had progressive local disease. Pathological complete response rates post surgery in triple negative, Her2 neu positive and ER positive group was 50%, 34% and 12% respectively. The sensitivity, specificity, positive predictive value and negative predictive value is tabulated below. Conclusions: Overall FDG PET CT showed good specificity with limited sensitivity for post NACT response assessment in breast cancer. Our results suggest that post NACT PET CT may have limited utility for clinical decision making and at present its use cannot be recommended outside of a clinical trial.[Table: see text]

CRY2 mediates the cognitive decline induced by sleep deprivation in 5xFAD mice.

Cryptochrome-2 (CRY2) is a core rhythm gene that plays a crucial role in DNA damage repair. The present study investigated the potential role of CRY2 in mediating sleep deprivation-induced cognitive decline in 5xFAD mice. To assess the effects of SD on different brain regions of the mouse brain, we used 18F FDG PET-CT. Cognitive function was evaluated using the Morris water maze test and Y-maze. Lentivirus was used for the overexpression of CRY2, and small interfering RNA (siRNA) was used for the downregulation of CRY2 to verify the effect of CRY2. We used qRT‒PCR and Western blotting to identify the downstream factors of CRY2 and evaluated the cognitive function of mice to confirm the effects of these factors. The AD mice exhibited cognitive decline after 21 days of SD and had higher expression of CRY2 compared to AD mice with normal sleep. Overexpression of CRY2 led to decreased cognitive function in AD mice, and the downregulation of CRY2 attenuated the SD-induced cognitive decline in AD mice. CRY2 reduced the expression and function of CISH, which reduced the inhibition of STAT1 phosphorylation and led to synaptic dysfunction. CISH overexpression attenuated the impairing effect of sleep deprivation on cognitive function in AD mice. Furthermore, 18F FDG PET-CT revealed that SD significantly reduced glucose metabolism in different brain regions of AD mice. Our study demonstrated that sleep deprivation upregulated CRY2 in the hippocampus of AD mice, which resulted in synaptic dysfunction by decreasing CISH-mediated STAT1 phosphorylation.

Primary alveolar soft part sarcoma of the ilium: A case report and literature review

Introduction: The primary alveolar soft part sarcoma (ASPS) of bone is extremely rare, and the number of published reporting cases is limited. Case Report: We present a 30-year-old woman with primary ASPS of ilium. Computed tomography and magnetic resonance imaging revealed a destructive and moth-eaten appearance in the ilium with a soft tissue mass. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) revealed high uptakes of FDG in the left ilium. ASPSCR1-TFE3 gene fusion was detected by reverse transcriptase polymerase chain reaction (RT-PCR). Wide resection was performed. One year after the surgery, a local recurrence developed. However, there has been no evidence of disease in the last eight years after the second surgery. Conclusion: 18F-fluorodeoxyglucose positron emission tomography-computed tomography and RT-PCR besides routine radiological and histopathological studies helped achieve the accurate diagnosis and provide appropriate treatment in the present case.

Segmentation-Free Outcome Prediction from Head and Neck Cancer PET/CT Images: Deep Learning-Based Feature Extraction from Multi-Angle Maximum Intensity Projections (MA-MIPs).

We introduce an innovative, simple, effective segmentation-free approach for survival analysis of head and neck cancer (HNC) patients from PET/CT images. By harnessing deep learning-based feature extraction techniques and multi-angle maximum intensity projections (MA-MIPs) applied to Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) images, our proposed method eliminates the need for manual segmentations of regions-of-interest (ROIs) such as primary tumors and involved lymph nodes. Instead, a state-of-the-art object detection model is trained utilizing the CT images to perform automatic cropping of the head and neck anatomical area, instead of only the lesions or involved lymph nodes on the PET volumes. A pre-trained deep convolutional neural network backbone is then utilized to extract deep features from MA-MIPs obtained from 72 multi-angel axial rotations of the cropped PET volumes. These deep features extracted from multiple projection views of the PET volumes are then aggregated and fused, and employed to perform recurrence-free survival analysis on a cohort of 489 HNC patients. The proposed approach outperforms the best performing method on the target dataset for the task of recurrence-free survival analysis. By circumventing the manual delineation of the malignancies on the FDG PET-CT images, our approach eliminates the dependency on subjective interpretations and highly enhances the reproducibility of the proposed survival analysis method. The code for this work is publicly released.

Comparing the Diagnostic Value of FDG PET or PET/CT With FDG PET/MR in Inflammatory Bowel Disease-A Systematic Review and Meta-analysis.

The aim of this study was to compare the diagnostic value of 18 F-FDG PET or PET/CT with FDG PET/MR in patients with inflammatory bowel disease (IBD). A comprehensive search was performed in PubMed for studies reporting the diagnostic performance of FDG PET (PET/CT) and FDG PET/MR in IBD from the inception of the database to March 14, 2024, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Fourteen studies were included in this systematic review and meta-analysis. Pooled estimates of segment-based sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for FDG PET (PET/CT) and FDG PET/MR were calculated alongside 95% confidence intervals. Summary receiver operating characteristic (SROC) curves were plotted, and the area under the SROC curve was determined alongside the Q * index. The segment-based pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the SROC curve of FDG PET (PET/CT) for diagnosing IBD (9 studies) were 0.81, 0.86, 5.76, 0.22, 31.92, and 0.92, respectively. Those of FDG PET/MR (5 studies) were 0.78, 0.92, 10.97, 0.25, 51.79, and 0.95. There was no significant difference in the abilities of detecting or excluding IBD between FDG PET (PET/CT) and FDG PET/MR. For diagnostic value in patients with IBD, there was no significant difference between FDG PET (PET/CT) and FDG PET/MR. Both FDG PET (PET/CT) and FDG PET/MR have demonstrated high diagnostic performance for accurate diagnosing in patients with IBD.

Abscopal Effect Demonstrated on [18F]FDG PET/CT in a Case of Renal Cell Carcinoma Postnephrectomy

Renal cell carcinoma accounts for 3% of all malignancies with many of them presenting with metastasis at the time of presentation. The abscopal effect, a phenomenon characterized by systemic bystander effects on nontargeted lesions due to local therapy, has been extensively studied in the context of radiotherapy and immunotherapy. However, documentation of the abscopal effect following surgery remains limited. We present a case of a 67-year-old Indian male diagnosed with clear cell renal cell carcinoma (RCC), who underwent left radical nephrectomy. Baseline staging and postnephrectomy follow-up scans with fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET-CT) revealed an FDG-avid primary lesion in the left kidney with metastasis to the left lung. Surprisingly, the follow-up FDG PET-CT scan demonstrated the resolution of the left lung metastasis, indicating the occurrence of the abscopal effect resulting from the local nephrectomy. This rare clinical observation highlights the potential of surgery to induce immunogenic tumor neoantigens release and inflammatory factors, leading to systemic antitumor effects. While the abscopal effect has been extensively studied in the context of radiotherapy and immunotherapy, there is a scarcity of studies reporting nephrectomy promoting such systemic effects. The combination of radiotherapy and immunotherapy has shown promising results in enhancing tumor immunosuppression and facilitating the abscopal effect. We report a case of RCC with lung metastasis showing abscopal effect with resolution of lung nodule postnephrectomy on 18-F-FDG PET-CT.

Role of [18F]FDG-PET/CT in Evaluation of Tumor Response to Chemoradiation Therapy for Advanced Colorectal Cancer

Objectives: The objective is to evaluate the efficacy of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) computed tomography (CT) in the evaluation of tumor response to preoperative/palliative chemoradiotherapy (CRT) for advanced colorectal cancer; including metastatic cancer at primary presentation and recurrent cancers with local and/or distant metastasis. Materials and Methods: Fifty patients with advanced rectal cancer underwent two point imaging with 18 FDG PET-CT before and after 3 weeks of completion of preoperative/palliative CRT in between 2016 and 2022. Patients with locally recurrent cancer also underwent radical surgery. The assessment consisted of the evaluation of the following metabolic PET parameters: Maximum standardized uptake value (SUVmax), SUVratio, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Response was assessed among the followed patients using RECIST 1.1 criteria. Observations and Results: There was a significant decline in the mean post therapy SUVmax and SUVratio as compared to baseline (P = 0.0001). Twenty-six out of 50 (52%) patients were classified as responders. A significant decrease in all parameters (SUVmax, SUVratio, TLG, and MTV) from baseline was observed in responders of the study when comparing with nonresponders (P &lt; 0.05). Besides SUVmax and SUVratio, the mean posttherapy TLG was significantly reduced in responders than nonresponders (P = 0.0065). Conclusion: PET-CT is a useful combined anatomic and functional imaging modality in monitoring tumor response to preoperative/palliative CRT in advanced rectal cancer, whether primary or recurrent, including metastatic cancers at presentation. Posttherapy SUV and TLG in particular are significantly associated with treatment response.