High FDG Uptake Research Articles

A Rare Case of Signet Ring Cell Lymphoma and Review of the Literature

Signet ring cell lymphoma (SRCL) is a non-Hodgkin's lymphoma with a very rare variant. Although this morphology is frequently seen in follicular lymphoma, it can also be observed in the group of diffuse large B-cell lymphomas. A seventy-six year old woman with known diagnosis of gastric adenocarcinoma, tubular type, moderately differentiate presented with a lymphadenopathy with high FDG uptake (SUVmax: 21.3) in PET/CT during follow-up. A tru-cut biopsy was performed for histopathological diagnosis. Diffuse infiltrative singet ring neoplastic cells showed negativity for PanCK, CK7, CK20, S100, SMA, calretinin and vimentin. The panel was then expanded to include SRCL, a rare variant of lymphoma. Additional immunohistochemical evaluation revealed positivity for CD20, CD19, PAX-5 and Bcl-2. Ki-67 proliferation index was about 80%. CD3, CD30, Myc, Bcl-6, ALK, Cyclin-D1, CD23, CD10, CD21, and MUM-1 were negative. EBER was also negative by chromogen in situ hybridization (CISH). Based on these data, diffuse large B-cell lymphoma (DLBCL) was considered. We herein reported a case of signet ring cell lymphoma discussed its clinical and morphological features with regard to the literature.

High 18F-FDG Uptake in Phosphoglyceride Crystal Deposition Disease of the Humerus Mimicking Chondrosarcoma.

A 82-year-old man presented with left humerus pain. MRI revealed a lesion in the left humerus appearing hyperintense on T2WI and hyperintense on DWI. 18F-FDG PET/CT demonstrated high FDG uptake in the lesion. Surgical resection was performed under the preoperative diagnosis of chondrosarcoma. However, a histopathological analysis confirmed the diagnosis of phosphoglyceride crystal deposition disease (PGDD). PGDD is an extremely rare disease, and this is the first report of PGDD occurring in the humerus. Bone lesions showing high uptake of FDG are usually malignant lesions; however, it is important to consider the possibility of benign diseases such as PGDD.

The utility of PET-CT in baseline and sequential characterisation of Pulmonary Pleomorphic Carcinoma

Pulmonary Pleomorphic Carcinomas (PPCs) represent a rare and aggressive subtype of Non-Small Cell Lung Cancer (NSCLC) that can only be definitively diagnosed on a surgical specimen. This study utilised PET-CT to evaluate radiological characteristics of PPCs. This study retrospectively evaluated the radiological characteristics of PCCs diagnosed in St James’s Hospital Dublin between 2012-2023. Computed Tomography (CT) and Positron Emission Tomography (FDG-PET) imaging features (size, location, density, shape, invasion, and growth kinetics) and standard uptake value for each lesion were evaluated. 39 PCCs were identified with a mean age of 66.5 years (range: 49-82 years). FDG-PET was performed in all 39 cases. Tumours demonstrated a high FDG uptake at baseline with a mean (SUV) of 12.6 (range: 1.4 - 36.9). A second interval PET-CT on average 3.3 months after the first in 3 cases demonstrated over 120% increase in SUV. The mean tumour size was 4.3 cm (range: 1.0 - 14.5 cm). Tumours developed rapid interval growth, reaching a mean maximum diameter of 6.6 cm (53.4%) within a mean of 2.1 months. Tumours were predominantly located in the upper lobe (71.8 %) and displayed necrotic features in 53.8 % of cases. 82.1% of tumours invaded the mediastinum. This study describes the largest cohort of Pulmonary Pleomorphic Carcinoma in the literature. Tumours demonstrate a high SUV on baseline imaging and demonstrate rapid growth on interval imaging and central necrosis. Please click on the 'PDF' for the full abstract!

18F-FDG PET/CT for the diagnosis and evaluation of antibiotic response in patients with left ventricular assistive device infection: A case report

The left ventricular assistive device (LVAD) is critical for end-stage heart failure patients. Centrifugal flow LVAD recipients have a 4-year survival rate of nearly 60%, with infection occurring in over 50% of patients within 2 years. Herein, we report a case of LVAD infection in a 60-year-old man. The patient presented with fever after 49 days following LVAD implantation. Culture of both blood and areas around the outflow cannula indicated an infection with Enterobacter cloacae and Staphylococcus aureus. After sequential treatment with meropenem and daptomycin, as well as abdominal incisional debridement, the patient’s symptoms of fever disappeared, but the inflammatory markers, such as the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level, remained abnormal. Five 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scans were performed to evaluate the infection. PET/CT revealed infected lesions around the lower segment of the outflow cannula with high FDG uptake. After continuous oral antibiotic treatment for more than 1 year, the infected areas with high FDG uptake around the outflow cannula gradually declined and eventually disappeared, consistent with the noted changes in both ESR and CRP levels in the serum. Multiple continuous 18F-FDG PET/CT scans can distinguish high FDG uptake areas of infection from sterile inflammatory areas, assisting in the accurate diagnosis of infection and evaluation of antibiotic treatment after LVAD implantation.

Classics in abdominal imaging: the "Lollipop sign" of epithelioid hemangioendothelioma.

A 58-year-old female was diagnosed with epithelioid hemangioendothelioma (EHE). The intrahepatic lesion exhibited a "Lollipop sign," associated with capsular retraction. On the PET/CT, there are multiple lesions in the lungs with variable high and low FDG uptake, and focal calcifications are present on CT. Additionally, destruction of the thoracic vertebrae has been observed.

Preoperative evaluation of mediastinal lymph nodes in non-small cell lung cancer using [68Ga]FAPI-46 PET/CT: a prospective pilot study

PurposeMediastinal nodal staging is crucial for surgical candidate selection in non-small cell lung cancer (NSCLC), but conventional imaging has limitations often necessitating invasive staging. We investigated the additive clinical value of fibroblast activation protein inhibitor (FAPI) PET/CT, an imaging technique targeting fibroblast activation protein, for mediastinal nodal staging of NSCLC.MethodsIn this prospective pilot study, we enrolled patients scheduled for surgical resection of NSCLC based on specific criteria designed to align with indications for invasive staging procedures. Patients were included when meeting at least one of the following: (1) presence of FDG-positive N2 lymph nodes, (2) clinical N1 stage, (3) central tumor location or tumor diameter of ≥ 3 cm, and (4) adenocarcinoma exhibiting high FDG uptake. [68Ga]FAPI-46 PET/CT was performed before surgery after a staging workup including [18F]FDG PET/CT. The diagnostic accuracy of [68Ga]FAPI-46 PET/CT for “N2” nodes was assessed through per-patient visual assessment and per-station quantitative analysis using histopathologic results as reference standards.ResultsTwenty-three patients with 75 nodal stations were analyzed. Histopathologic examination confirmed that nine patients (39.1%) were N2-positive. In per-patient assessment, [68Ga]FAPI-46 PET/CT successfully identified metastasis in eight patients (sensitivity 0.89 (0.52–1.00)), upstaging three patients compared to [18F]FDG PET/CT. [18F]FDG PET/CT detected FDG-avid nodes in six (42.8%) of 14 N2-negative patients. Among them, five were considered non-metastatic based on calcification and distribution pattern, and one was considered metastatic. In contrast, [68Ga]FAPI-46 PET/CT correctly identified all non-metastatic patients solely based on tracer avidity. In per-station analysis, [68Ga]FAPI-46 PET/CT discriminated metastasis more effectively compared to [18F]FDG PET/CT-based (AUC of ROC curve 0.96 (0.88–0.99) vs. 0.68 (0.56–0.78), P < 0.001).Conclusion[68Ga]FAPI-46 PET/CT holds promise as an imaging tool for preoperative mediastinal nodal staging in NSCLC, with improved sensitivity and the potential to reduce false-positive results, optimizing the need for invasive staging procedures.

Atypical Kikuchi-Fujimoto Disease: FDG-PET Contribution To The Diagnosis.

Kikuchi-Fujimoto disease (KFD) typically presents with small, painful, localised cervical lymphadenopathy.KFD has atypical patterns showing painless and generalised lymphadenopathy.Fluorodeoxyglucose positron emission tomography (FDG-PET) could be useful for diagnosing not only malignant lymphoma but also KFD.

Axillary Lymph Node Metastasis as the First Symptom of Colon Cancer.

Axillary lymph node metastasis in colon cancer is extremely rare. We describe the FDG PET/CT findings in a 61-year-old woman who presented with a mass in the right axilla, which revealed irregular thickening of the ascending colon wall, as well as multiple enlarged lymph nodes in the ileocecal mesentery, para-aortic region, and right axilla with higher uptake of FDG. Ascending colon carcinoma with lymph node metastasis in the right axilla was confirmed by pathological examination.

Predicting Treatment Response of Esophageal Cancer Treated by Concurrent Chemoradiotherapy Using Pre- and Posttreatment 18F-FDG PET Metabolic Characteristics.

This study hypothesizes that metabolic characteristics of esophageal tumors can be used to predict treatment response, which considers changes in the primary tumor and lymph nodes, for patients receiving neoadjuvant concurrent chemoradiotherapy (CCRT). This study retrospectively included 60 esophageal cancer patients receiving CCRT followed by surgery. All patients received 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) examinations prior to CCRT and in the interval between CCRT and surgery. On the pre-treatment FDG PET/CT images, the maximum standardized uptake value (SUVMaxPre) within the primary tumor was identified. By computerized methods, the CT images of pre- and post-treatment FDG PET/CT were registered. Then, the coordinates of SUVMaxPre were transformed to the post-treatment FDG PET images and delineated a sphere with a diameter of 5 cm to indicate the tumor position. After excluding air, the sphere was partitioned into several metabolic volumes by the optimal dichotomy of high and low metabolic FDG uptakes. Finally, the volume with the shortest distance to the center was adopted and represented by the maximum standardized uptakes (SUVMaxPost). Two additional features, SUVDiff and SUVDiffR, were defined as SUVMaxPost - SUVMaxPre and (SUVMaxPost - SUVMaxPre) / SUVMaxPre. Besides, for defining treatment response, the patients with and without residual tumors were defined as ypT+ and ESOCR based on the histopathology results of surgery. The ESOCR was further classified into pCR to indicate the absence of lymph node metastasis and LNM for remaining. Finally, the area under the receiver operating characteristic curve analysis (AUC) was conducted to assess the features' ability to differentiate two treatment responses. Kruskal-Wallis test was used to evaluate the differences in features between treatment responses. Of the 60 patients, 55 were men (92%), and the mean age was 58. The number of tumors at the esophagus's upper, middle, and lower third were 8, 18, and 34, respectively. Ninety-eight percent of the tumors were squamous cell carcinomas (59/60). The patient numbers of ypT+ and ESOCR were 43 and 17 of which contained 13 pCR and 4 LNM. The SUVDiff and SUVDiffR exhibited a significant ability to identify the ESOCR with AUC = .337 (p = .05) and AUC = .290 (p = .012), respectively. In addition, a statistically significant difference was found among the three groups of ypT+, pCR, and LNM on SUVMaxPre (H = 6.252 and p = .044), SUVDiff (H = 7.948 and p = .019), and SUVDiffR (H = 8.405 and p = .015). In the post-hoc tests corrected by the Bonferroni, the difference between ypT+ and LNM was significant on these features. The metabolic characteristics extracted from pre- and post-treatment FDG PET/CT images could indicate treatment response and disease progression. Further studies are warranted.

Comparison of SUVA/V and SUVA-V for Evaluating Atherosclerotic Inflammation in 18F-FDG PET/CT.

This study aimed to compare the clinical significance of two parameters, division of standardized uptake value (SUV) of target arterial activity by background venous blood pool activity (SUVA/V) and subtraction of background venous blood pool activity from SUV of target arterial activity (SUVA-V) of carotid arteries with atherosclerotic plaques using 18F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT). Patients aged 50 years or more who were diagnosed with carotid artery stenosis of 50% or more with carotid Doppler ultrasonography and had torso 18F-FDG PET/CT were enrolled retrospectively and classified patients who developed cerebrovascular events (CVEs) within 5 years after 18F-FDG PET/CT scan as the active group and patients who did not experience the CVE within 5 years as an inactive group. We calculated SUVA/V and SUVA-V using measurements of SUVmax of carotid arteries and mean SUV of superior vena cava (SVC). SUVA-V, SUVA-V_high, and SUVA-V_low were significantly higher in the active group than in the inactive group, but neither SUVA/V, SUVA/V_high, nor SUVA/V_low showed significant differences between the active and inactive groups. The difference in rank between groups of SUVA/V_high and SUVA/V_low was greater than the difference in rank between groups of SUVA-V_high and SUVA-V_low. The CVE incidence differed between SUVA/V_high and SUVA/V_low of high carotid FDG uptake, but the CVE incidence did not differ between SUVA-V_high and SUVA-V_low of high carotid FDG uptake. SUVA-V may be a more rational solution than SUVA/V for evaluating atherosclerotic plaque inflammation on 18F-FDG PET/CT.

Imaging characteristics of tenosynovial giant cell tumors on 18F-fluorodeoxyglucose positron emission tomography/computed tomography: a retrospective observational study

Background18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) is useful for assessing location, metastasis, staging, and recurrence of malignant tumors. Tenosynovial giant cell tumor (TSGCT) is a benign tumor; however, some studies have reported that TSGCTs have a high uptake of FDG. Few studies have reported on the detailed evaluation of TSGCT using 18F-FDG-PET/CT. The purpose of the current study is to evaluate the image characteristics and locations, particularly where possible, with or without, extra-articular invasion from TSGCT of the knee in 18F-FDG-PET/CT could occur.MethodsWe retrospectively reviewed the patients with TSGCT who were diagnosed pathologically either by biopsy or surgical specimen. Furthermore, we evaluated the difference of the maximum standardized uptake value (SUVmax) between diffused TSGCT with extra-articular invasion and TSGCT with intra-articular localization in the knee.ResultsThe study consisted of 20 patients with TSGCT. The mean SUVmax of TSGCT was 12.0 ± 6.50. There were five patients with TSGCT arising in the knee with extra-articular invasion and six with TSGCT with intra-articular localization. The mean SUVmax of TSGCT with extra-articular invasion and those with intra-articular localization were 14.3 ± 6.00 and 5.94 ± 3.89, respectively. TSGCT with extra-articular invasion had significantly higher SUVmax than TSGCT with intra-articular localization (p < 0.05).ConclusionsTSGCT revealed high FDG uptake. Furthermore, SUVmax was higher in diffused TSGCT with extra-articular invasion than in intra-articular localized TSGCT; this may reflect its local aggressiveness.

FDG uptake reflects an immune-enriched subtype of thyroid cancer: Clinical implications of imaging-based molecular characterization.

Iodine and FDG uptakes have been established as methods to define the biological properties of thyroid cancer. As various cells in the tumor microenvironment (TME) affect tumor metabolism, we investigated the association between glucose metabolism in thyroid cancer and the TME using transcriptomic analyses. We used F-18 FDG PET and RNA sequencing data of thyroid cancer to find associations between TME cell types and glucose metabolism. In addition, publicly available single-cell RNA sequencing data of papillary thyroid cancer was used to investigate glucose metabolism in cell types of the TME. The correlations between the FDG uptake and biological properties of the TME, including glucose metabolism and tumor differentiation score (TDS) were evaluated. Estimation of the proportions of immune and cancer cells (EPIC) was performed. The biological properties of each cell type were also assessed in the single-cell RNA sequencing data. FDG uptake showed a positive correlation with the enrichment score of macrophages and glycolysis activity. In single-cell RNA sequencing, immune cells had both high glucose transporters (GLUTs) and glycolysis signatures, while thyrocytes including cancer cells showed relatively low GLUTs and glycolysis signatures, suggesting that FDG uptake mainly occurred in immune cells of the TME. Moreover, the high GLUTs of myeloid cells were negatively associated with TDS. Our findings suggest that thyroid cancer with high FDG uptake can be mediated by enriched immune cells of the TME. We suggest that FDG uptake in thyroid cancer could be a marker for the immune-rich type and provide clinical implications for treatment stratification.

Intraductal oncocytic papillary neoplasm of the pancreas: clinical and radiological features compared to those of intraductal papillary mucinous neoplasm

PurposeThis study aimed to characterize the clinical and imaging findings of intraductal oncocytic papillary neoplasm of the pancreas (IOPN-P) compared to those of intraductal papillary mucinous adenoma/carcinoma (IPMA/IPMC).MethodsThis multi-institutional retrospective study reviewed the clinical, imaging, and pathological findings of 21 patients with pathologically proven IOPN-P. Twenty-one computed tomography (CT) and magnetic resonance imaging, and seven 18F-fluorodeoxyglucose (FDG)-positron emission tomography were performed before surgery. The following findings were evaluated: preoperative blood test results, lesion size and location, pancreatic duct diameter, contrast-enhancement effect, bile duct and peripancreatic invasion, maximum standardized uptake (SUVmax) value, and pathological stromal invasion.ResultsSerum carcinoembryonic antigen (CEA) and cancer antigen 19-9 (CA19-9) levels were significantly higher in the IPMN/IPMC group than in the IOPN-P group. Except in one patient, IOPN-P showed multifocal cystic lesions with solid components or a tumor in the main pancreatic duct (MPD) with dilatation. IOPN-P had a higher frequency of solid parts and a lower frequency of downstream MPD dilatation than IPMA. IPMC showed smaller overall cyst size, more radiological peripancreatic invasion, and worse recurrence-free and overall survival than IOPN-P. The average SUVmax value of IOPN-P was 7.5. Pathologically, 17 of the 21 IOPN-Ps had a malignant component, and six showed stromal invasion.ConclusionIOPN-P shows cystic-solid lesions similar to IPMC but has lower serum CEA and CA19-9 levels, larger overall cyst size, lower frequency of peripancreatic invasion, and more favorable prognosis than IPMC. Moreover, the high FDG uptake by IOPN-Ps may be a characteristic finding of this study.Graphical abstract

Contribution of Metabolic Parameters and Pericolic Fat Stranding on Preoperative 18F-FDG PET/CT in Predicting Post-operative Histopathology and Outcome in Colorectal Cancer.

We aimed to investigate the additional value of preoperative PET/CT and reveal relationships between metabolic parameters, pericolic fat stranding finding, postoperative histopathology, and overall survival in colorectal cancer (CRC). CRC patients who underwent preoperative PET/CT between January 2017-December 2021 were analyzed. Lymph nodes, organ metastases, and metabolic parameters were evaluated from PET/CT. The pericolic fat stranding was evaluated from CT component. Relationships between these factors and postoperative histopathological findings were statistically analyzed. Survival analyses were performed. Ninety-one patients (59 males, 32 females) were included in the study. All tumors showed high FDG uptake (mean SUVmax 19.5 ± 9.9). SUVmax of the tumor differed significantly at T3 and T4 stages (p = 0.041). A significant correlation was found between MTV, TLG values and the differentiation degree (p = 0.005, 0.003, respectively). PET/CT predicted the N stage with a high accuracy rate (80%). PET/CT found additional metastases that changed treatment decisions in one-third of patients. A relationship was found between tumor length, surgical margin, lymphovascular invasion and pericolic fat stranding. In multivariate analysis, differentiation degree (HR = 26.1, 95%CI 1.672-408.467), MTV (HR = 0.3, 95%CI 0.071-0.841), TLG (HR = 3.5, 95%CI 1.065-11.193), and lymphovascular invasion (HR = 0.2, 95%CI 0.026-0.853, p = 0.033) were independent factors affecting overall survival. Preoperative PET/CT contributes to CRC management by detecting additional metastases as well as predicting prognosis and postoperative findings such as T stage, N stage and tumor differentiation. The SUVmax may differentiate between T3 and T4 tumor. Reporting of pericolic fat stranding may contribute to the estimation of lymphatic invasion and positive surgical margin.

FDG PET/CT as a Tool for Early Detection of Bleomycin-Induced Pulmonary Toxicity

Bleomycin-induced pulmonary toxicity (BPT) is a serious and potentially fatal complication of bleomycin, a key component of Hodgkin lymphoma (HL) treatment. Before ours, only one published study evaluated the predictability of 18F-FDG-PET/CT for the early diagnosis of BPT. In this retrospective cohort study, 18F-FDG-PET/CT scans of adult HL patients treated with bleomycin at an urban academic center over five years were assessed by radiologists blinded to the clinical information, and scans were correlated with clinical BPT. We found 11 HL patients with 54 interim or end-of-treatment 18F-FDG-PET/CT scans who had received bleomycin. Five of the eleven (5/11, 45%) patients had radiographic changes in PET/CT and developed clinical BPT. Patients with clinical BPT had higher FDG uptake in lungs compared to those who did not (SUVmax mean 2.66 (CI 1.8–3.7) vs. 0.86 (CI 0.4–1.9), Mann–Whitney U test, p &lt; 0.05). In a separate cohort analysis, we compared HL patients with clinical BPT (9/25, 36%) and without clinical BPT (16/25, 64%) to assess potential risk factors. Low hemoglobin (p = 0.037) and high ESR values (p = 0.0289) were associated with clinical BPT. Furthermore, gender, stage, histology, prior lung radiation, G-CSF, or steroids did not significantly confer a higher risk of BPT. 18F-FDG-PET/CT imaging, which is routinely used to assess treatment response in HL, is useful for early detection of BPT, which can have high mortality and morbidity.

An unusual finding after adrenal surgery: a case series of adrenal schwannomas.

Adrenal schwannomas are rare benign tumors with no specific imaging and laboratory findings to diagnose preoperatively. Due to the limited number of cases in the literature, clinical, imaging, and pathological findings are presented in this study. Case 1 is a 61-year-old woman patient who has a 31-mm mass in the right adrenal gland. This mass was nonfunctional; in imaging studies, this mass had a cystic necrotic component, and high 18-fluorodeoxyglucose (FDG) uptake was seen. There was no metaiodobenzylguanidine (MIBG) uptake. Laparoscopic transabdominal right adrenalectomy was performed, and the pathology result was consistent with adrenal schwannomas. Case 2 is a 63-year-old man patient who presented with a 38-mm mass in the left adrenal gland. This mass was nonfunctional and similar to that in Case 1; this mass had a cystic component. Laparoscopic transabdominal left adrenalectomy was performed. The diagnosis of adrenal schwannoma with degeneration was revealed. Case 3 was a 72-year-old woman patient admitted to the hospital for a 125-mm left adrenal mass. Similar to Case 1, this mass also had a cystic necrotic component in imaging studies. High FDG uptake was seen, and the patient underwent conventional adrenalectomy due to the suspicion of malignancy. After pathological evaluation, a diagnosis of adrenal schwannoma was made. A main diagnostic challenge in adrenal schwannomas is the preoperative diagnosis. These masses have no pathognomonic finding or specific hormonal function. Imaging findings of these masses may increase the suspicion of malignancy, which may affect decisions for surgery and the surgical technique.

Dedifferentiated liposarcoma lung metastases with different FDG-PET/CT findings

BackgroundDedifferentiated liposarcoma (DDLPS) is a rare tumor and generally shows poor prognosis with the lung frequent metastatic site. 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is used for staging or metastatic evaluation of this disease. We report a case of bilateral lung metastases of DDLPS showing uncommon imaging on FDG-PET/CT with completely different FDG uptake, which made preoperative diagnosis difficult.Case presentationThe patient was a male in his 60 s and bilateral lung nodules were noted after proton beam therapy for retroperitoneal DDLPS. FDG-PET/CT showed high FDG uptake in the left S3 15-mm nodule but no uptake in the right S8 10-mm nodule. Thoracoscopic wedge resection for the left nodule was performed, and the pathology revealed metastasis of dedifferentiated liposarcoma. After resection of the left nodule, the right S8 nodule enlarged without FDG uptake. Thoracoscopic right S8 segmentectomy was performed, and metastasis of dedifferentiated liposarcoma was diagnosed. The 2 tumors showed completely different appearances on FDG-PET/CT with similar histopathological findings.ConclusionsWe encountered a case of multiple pulmonary metastases of DDLPS which did not follow the same imaging appearance on FDG-PET/CT. Appropriate timing of surgical resection for pathological diagnosis should be determined carefully.

PET/CT imaging of giant primary pulmonary meningioma: a case report and literature review

BackgroundAn ectopic meningioma, such as a primary pulmonary meningioma (PPM), is a rare type of tumor that primarily originates outside of the central nervous system. The most common presentation of PPM is isolated pulmonary nodules or masses, and most of them are benign. Only sporadic cases have been reported. This case reported a giant primary pulmonary meningioma and systematically reviewed previously reported cases in the literature.Case presentationA 55-year-old female suffered from asthma after activity, chest tightness, and a persistent dry cough for 2 months. Chest computed tomography (CT) showed a huge mass with calcification in the left lower lobe. And positron emission tomography (PET)/CT revealed mild FDG accumulation of the mass. The mass was finally surgically removed and PPM was confirmed according to histopathologic examinations.ConclusionPPM is a rare disease with heterogeneity not only in CT features but also in glucose metabolism. FDG uptake levels do not identify benign from malignant, benign PPM may have high FDG uptake and malignant may have low.

Prognostic value of 18F-fluorodeoxyglucose uptake in the bone marrow on pretreatment positron emission tomography/computed tomography in patients with esophageal cancer who underwent esophagectomy.

Increased 18F-fluorodeoxyglucose (FDG) uptake in the bone marrow (BM) on positron emission tomography/computed tomography (PET/CT) clinically reflects increased BM metabolism owing to systemic inflammation, bacterial infection, anemia, and cytokine-producing tumors. The association between FDG uptake in the BM and prognosis after esophagectomy for esophageal cancer has not been investigated. This study included 651 patients who underwent PET/CT before any treatment and McKeown esophagectomy for esophageal cancer between June 2007 and August 2021. The pretreatment degree of FDG uptake in the BM was evaluated using a visual assessment criterion. Patients were divided into low- and high-FDG uptake groups. We retrospectively investigated whether the degree of FDG uptake in the BM was associated with clinicopathological and surgical backgrounds, blood parameters, and prognosis. High FDG uptake in the BM was significantly associated with elevated white blood cell and neutrophil counts, increased C-reactive protein levels, decreased hemoglobin, serum albumin, and total cholesterol levels. High FDG uptake in the BM was an independent predictor of worse overall survival in clinical stages 0-II esophageal cancer (hazard ratio, 2.27; 95% confidence interval, 1.097-4.695; P = 0.027). Worse overall survival was also associated with advanced age, low American Society of Anesthesiologists physical status, an advanced clinical stage, and high intraoperative blood loss. Increased FDG uptake in the BM on pretreatment PET/CT may be a surrogate indicator of various clinically disadvantageous backgrounds and may act as a predictor of poor prognosis after esophageal cancer surgery.

Improving the Classification of PCNSL and Brain Metastases by Developing a Machine Learning Model Based on 18F-FDG PET.

Background: The characteristic magnetic resonance imaging (MRI) and the positron emission tomography (PET) findings of PCNSL often overlap with other intracranial tumors, making definitive diagnosis challenging. PCNSL typically shows iso-hypointense to grey matter on T2-weighted imaging. However, a particular part of PCNSL can demonstrate T2-weighted hyperintensity as other intracranial tumors. Moreover, normal high uptake of FDG in the basal ganglia, thalamus, and grey matter can mask underlying PCNSL in 18F-FDG PET. In order to promote the efficiency of diagnosis, the MRI-based or PET/CT-based radiomics models combining histograms with texture features in diagnosing glioma and brain metastases have been widely established. However, the diagnosing model for PCNSL has not been widely reported. The study was designed to investigate a machine-learning (ML) model based on multiple parameters of 2-deoxy-2-[18F]-floor-D-glucose (18F-FDG) PET for differential diagnosis of PCNSL and metastases in the brain. Methods: Patients who underwent an 18F-FDG PET scan with untreated PCNSL or metastases in the brain were included between May 2016 and May 2022. A total of 126 lesions from 51 patients (43 patients with untreated brain metastases and eight patients with untreated PCNSL), including 14 lesions of PCNSL, and 112 metastatic lesions in the brain, met the inclusion criteria. PCNSL or brain metastasis was confirmed after pathology or clinical history. Principal component analysis (PCA) was used to decompose the datasets. Logistic regression (LR), support vector machine (SVM), and random forest classification (RFC) models were trained by two different groups of datasets, the group of multi-class features and the group of density features, respectively. The model with the highest mean precision score was selected. The testing sets and original data were used to examine the efficacy of models separately by using the weighted average F1 score and area under the curve (AUC) of the receiver operating characteristic curve (ROC). Results: The multi-class features-based RFC and SVM models reached identical weighted-average F1 scores in the testing set, and the score was 0.98. The AUCs of RFC and SVM models calculated from the testing set were 1.00 equally. Evaluated by the original dataset, the RFC model based on multi-class features performs better than the SVM model, whose weighted-average F1 scores of the RFC model calculated from the original data were 0.85 with an AUC of 0.93. Conclusions: The ML based on multi-class features of 18F-FDG PET exhibited the potential to distinguish PCNSL from brain metastases. The RFC models based on multi-class features provided comparatively high efficiency in our study.