Case report: Evaluation of cutaneous squamous cell carcinoma metastasized to lymph nodes using 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in a dog

Introduction

18F-fluorodeoxy-2-deoxy-D-glucose (FDG) positron emission tomography (PET) is used with high sensitivity in human medicine for initial staging and treatment planning of cutaneous squamous cell carcinoma (SCC). To the best of our knowledge, 18F-FDG PET/computed tomography (CT) has not been used for canine cutaneous SCC with lymph node metastasis.

Case presentation

A 13 year-old spayed female Maltese had rapidly growing flank SCC, which had previously recurred twice. Radiography revealed no metastases. On PET/CT imaging, increased FDG uptake was observed not only in the flank but also in the left axillary lymph node and left inguinal lymph node (standardized uptake value max [SUVmax]: 8.602, 5.354, and 1.96, respectively). Despite the evidence of metastasis, palliative skin mass resection with a 3-cm margin and lymph node dissection were performed. Histopathological examination confirmed the presence of metastases in both lymph nodes.

Discussion

18F-FDG PET/CT is valuable for the detection of metastatic tumors in various organs. Cutaneous SCC can accumulate 18F-FDG, making it detectable on PET/CT. In this dog with flank SCC, 18F-FDG-PET/CT showed high SUVmax values, indicating its potential for tumor assessment. In veterinary medicine, SUVmax values of 2.5-3.5 are commonly used to identify metastatic lymph nodes in other cancers. Therefore, the interpretation of an SUVmax of 1.96 in an inguinal lymph node for metastatic involvement may be uncertain. Owing to the partial volume effect, 18F-FDG PET/CT has limited sensitivity in identifying LN metastases, particularly in cases of small lesions. Lower SUVmax values adjusted for smaller sizes may better distinguish between benign and malignant lymph nodes. Hence, combining differentiated SUVmax cut-offs based on lymph node size with CT assessment could enhance lymph node evaluation and assist in surgical planning.

18F-Fluorodeoxyglucose Positron Emission Tomography-Based Risk Score Model for Prediction of Five-Year Survival Outcome after Curative Resection of Non-Small-Cell Lung Cancer

The aim of our retrospective study is to develop and assess an imaging-based model utilizing 18F-FDG PET parameters for predicting the five-year survival in non-small-cell lung cancer (NSCLC) patients after curative surgery. A total of 361 NSCLC patients who underwent curative surgery were assigned to the training set (n = 253) and the test set (n = 108). The LASSO regression model was used to construct a PET-based risk score for predicting five-year survival. A hybrid model that combined the PET-based risk score and clinical variables was developed using multivariate logistic regression analysis. The predictive performance was determined by the area under the curve (AUC). The individual features with the best predictive performances were co-occurrence_contrast (AUC = 0.675) and SUL peak (AUC = 0.671). The PET-based risk score was identified as an independent predictor after adjusting for clinical variables (OR 5.231, 95% CI 1.987-6.932; p = 0.009). The hybrid model, which integrated clinical variables, significantly outperformed the PET-based risk score alone in predictive accuracy (AUC = 0.771 vs. 0.696, p = 0.022), a finding that was consistent in the test set. The PET-based risk score, especially when integrated with clinical variables, demonstrates good predictive ability for five-year survival in NSCLC patients following curative surgery.

An Uncommon Case of Pediatric Nasopharyngeal Carcinoma with Bone Metastases and Enchondromas Evaluated Using 18F-FDG PET/CT

Nowadays, the utility of positron emission tomography/computed tomography (PET/CT) is well established in nasopharyngeal carcinoma (NPC). The incidence of NPC in the West population, especially in children, is very low. We present the first Italian case of a pediatric patient with NPC followed up with 18F-fluorodeoxyglucose (18F-FDG) PET/CT scan in addition to the standard follow-up imaging methods, including CT and magnetic resonance imaging. The 18F-FDG PET/CT scan was helpful in discriminating between metastatic and benign osseous lesions, thereby helping clinicians to determine the most appropriate therapeutic regimen. These findings support the clinical utility of 18F-FDG PET/CT in the diagnostic work-up of pediatric patients with NPC.

Diagnostic Performance of FAPI PET/CT vs. 18F-FDG PET/CT in Evaluation of Liver Tumors: A Systematic Review and Meta-analysis

Objectives

Primary liver tumors constitute one of the most common tumors. These are aggressive tumors with poor survival. Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), most commonly used functional imaging, shows limited tracer retention and poor tumor to background ratios (TBR). Novel 68Ga-fibroblast-activation-protein inhibitor (FAPI) PET/CT has shown better tracer uptake and detection efficacy in liver tumors. However, most of the available literature is limited to single center studies with limited number of patients. So, we tried to review and analyze the head-to-head comparison of 18F-FDG PET/CT and 68Ga-FAPI PET/CT in evaluation of liver tumors.

Methods

Literature available on head to head comparison of diagnostic accuracy of 18F-FDG PET/CT and 68Ga-FAPI PET/CT was searched in databases like PubMed, SCOPUS, EMBASE and Google Scholar for published original studies till April 2023. The relevant studies were selected and assessed using the Revised Tool for the Quality Assessment of Diagnostic Accuracy Studies-2 checklist. A random-effect model was used for calculating pooled sensitivity and specificity. They were represented with 95% confidence intervals (95% CI) and demonstrated in Forest plots. I-square statistic was used to assess heterogeneity in the studies.

Results

Pooled sensitivity and specificity of FAPI PET/CT and 18F-FDG PET/CT for detection of primary liver tumors was 94.3% (95% CI: 90.6-96.8%); 89.3% (95% CI: 71.8-97.7%) and 56.1% (95% CI: 49.7-62.5%); 96.4% (95% CI: 81.7-99.9%) respectively. Pooled sensitivity for detection of extrahepatic metastatic disease was 92.2% (range: 88.1-100%; 95% CI: 87.8-95.4%) and 72.4% (range: 69.8-76.5; 95% CI: 65.9-78.2%) respectively. Also, the maximum standardized uptake value (SUVmax) and TBR were higher for FAPI PET/CT than 18F-FDG PET/CT in the included studies.

Conclusion

Overall, FAPI PET/CT showed higher sensitivity for detection of liver tumors with better SUVmax and TBR than 18F-FDG PET/CT.

The value of 18F-FDG PET/CT in Langerhans cell histiocytosis

OBJECTIVE

To investigate the value of 18F-FDG PET/CT in diagnosis and disease evaluation of Langerhans cell histiocytosis (LCH).

METHODS

A retrospective analysis of 31 patients with LCH confirmed by histopathology was performed. A systematic analysis of the PET/CT imaging manifestations of LCH was performed, recording patients who were treated and receiving PET/CT for efficacy evaluation. In addition, clinical and laboratory data of LCH patients were collected, and the correlation between these data and PET/CT metabolic parameters was initially investigated.

RESULTS

Of the 31 patients, thirty had at least 1 PET/CT positive lesions (96.7%), and one had only skin damage without abnormalities on PET/CT. Of 31 patients, fifteen (48.4%) had single system (SS) disease (9 cases with a single site and 6 cases with multiple sites) and 16 (51.6%) had multisystem (MS) disease (6 low risk and 10 high risk cases). The incidence of LCH lesions in the bone, lymphatic system, pituitary gland, liver, soft tissue, thyroid gland, thymus, and lungs was 20 cases (64.5%), 12 cases (38.7%), 3 cases (9.7%), 2 cases (6.5%), 2 cases (6.5%), 1 case (3.2%), 1 case (3.2%), and 8 cases (25.8%), respectively. A total of 21 PET/CT follow-up scanning were performed in 13 patients receiving chemotherapy, with 13 (61.9%) partial metabolic remission (PMR), 6 (28.6%) progressive metabolic disease (PMD), and 2 (9.5%) stable metabolic disease (SMD), according to PET Response Evaluation Criteria in Solid Tumors (PRECIST) 1.0. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and Lactic Dehydrogenase (LDH) were positively correlated with TTLG (total TLG) (R2 = 0.3256, 0.2409, 0.4205, P < 0.05). The Re-examine SUVmax is positively correlated with re-examine LDH (R2 = 0.7285, P < 0.05).

CONCLUSIONS

18F-FDG PET/CT is an effective way to diagnose and evaluate LCH. PET metabolic parameters were associated with laboratory inflammatory markers, suggesting that 18F-FDG PET/CT may be helpful in evaluating disease activity of LCH.

Exceptionally Rare Isolated Thyroidal Metastasis of Pulmonary Carcinosarcoma: A Tale of 18F-FDG-positive Thyroid Nodule

Pulmonary carcinosarcomas (PCS) are uncommon and aggressive malignant tumors with epithelial and mesenchymal components and have a worse prognosis than other non-small-cell lung cancers. Metastases of non-thyroidal malignancies to the thyroid are rare. We reported a unique case of isolated thyroidal metastasis of PCS and discussed 18F-fluorodeoxyglucose (18F-FDG) positivity in incidentally found thyroid nodules on 18F-FDG positron emission tomography scan.

18F-FDG PET/CT Imaging for Treatment Response Assessment of Cardiac Primitive Neuroectodermal Tumor

Primitive neuroectodermal tumors (PNETs) are rare and aggressive members of the small round cell carcinoma family. Generally, PNETs are classified into two main groups: PNETs of the central nervous system and PNETs of the peripheral nervous system. Herein, we report the therapy response assessment of a rare case of isolated cardiac PNET using 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) imaging. Given that physiological cardiac FDG uptake is typically observed, assessing FDG avid lesions in the myocardium presents a challenge for FDG PET/CT. This case holds significance because of the rarity of the disease and the challenging nature of the site for FDG PET/CT imaging.

Endoscopic Evaluation of PET/CT Abnormalities in the Gastrointestinal Tract: Yield and Approach

BACKGROUND

Unexpected hypermetabolic activity is often encountered in the gastrointestinal tract when PET/CT is performed for various indications, prompting endoscopic evaluation. Our aim was to characterize the types of lesions seen in segments of the gastrointestinal tract with unexpected PET/CT abnormalities as well as clinically significant lesions seen on endoscopy which did not produce a PET/CT abnormality to guide the endoscopist tasked with evaluating these imaging findings.

METHODS

We retrospectively reviewed a database of endoscopies performed at City of Hope Comprehensive Cancer Center between January 1, 2016 and September 30, 2021 for an indication of "abnormal PET." We divided the gastrointestinal tract into segments and defined categories of endoscopic/histologic findings for each segment. We counted the number of segments with an abnormal PET/CT finding and corresponding endoscopic/histologic abnormality as well as the number of segments with an endoscopic/histologic abnormality but normal PET/CT.

RESULTS

PET/CT identified 209 segments with hypermetabolic activity, 109 of which had corresponding endoscopic/histologic abnormalities. In the jejunum and ileum, all corresponding lesions were malignant. Seventy-three percent of corresponding lesions in the stomach were H. pylori positive. PET/CT failed to detect 34.7% of clinically significant lesions diagnosed endoscopically, including 1 malignancy in the transverse colon and many inflammatory or low-risk premalignant lesions.

CONCLUSION

PET/CT abnormalities seen in the small bowel should be evaluated urgently as nearly all correlates were malignant, while abnormalities in the stomach should prompt workup for H. pylori. Most lesions missed by PET/CT were inflammatory or low-risk premalignant yet clinically significant, confirming the need to inspect the entirety of the upper or lower gastrointestinal tract during endoscopy.

Visualization of small brain nuclei with a high-spatial resolution, clinically available whole-body PET scanner

OBJECTIVE

To verify the visibility of physiological 18F-fluorodeoxyglucose (18F-FDG) uptake in nuclei in and around the brainstem by a whole-body (WB) silicon photomultiplier positron emission tomography (SiPM-PET) scanner with point-spread function (PSF) reconstruction using various iteration numbers.

METHODS

Ten healthy subjects (5 men, 5 women; mean age, 56.0 ± 5.0 years) who underwent 18F-FDG PET/CT using a WB SiPM-PET scanner and magnetic resonance imaging (MRI) of the brain including a spin-echo three-dimensional sampling perfection with application-optimized contrasts using different flip angle evolutions fluid-attenuated inversion recovery (3D-FLAIR) and a 3D-T1 magnetization-prepared rapid gradient-echo (T1-MPRAGE) images were enrolled. Each acquired PET image was reconstructed using ordered-subset expectation maximization (OSEM) with iteration numbers of 4, 16, 64, and 256 (subset 5 fixed) + time-of-flight (TOF) + PSF. The reconstructed PET images and 3D-FLAIR images for each subject were registered to individual T1-MPRAGE volumes using normalized mutual information criteria. For each MR-coregistered individual PET image, the pattern of FDG uptake in the inferior olivary nuclei (ION), dentate nuclei (DN), midbrain raphe nuclei (MRN), inferior colliculi (IC), mammillary bodies (MB), red nuclei (RN), subthalamic nuclei (STN), lateral geniculate nuclei (LGN), medial geniculate nuclei (MGN), and superior colliculi (SC) was visually classified into the following three categories: good, clearly distinguishable FDG accumulation; fair, obscure contour of FDG accumulation; poor, FDG accumulation indistinguishable from surrounding uptake.

RESULTS

Among individual 18F-FDG PET images with OSEM iterations of 4, 16, 64, and 256 + TOF + PSF, the iteration numbers that showed the best visibility in each structure were as follows: ION, MRN, LGN, MGN, and SC, iteration 64; DN, iteration 16; IC, iterations 16, 64, and 256; MB, iterations 64 and 256; and RN and STN, iterations 16 and 64, respectively. Of the four iterations, the 18F-FDG PET image of iteration 64 visualized FDG accumulation in small structures in and around the brainstem most clearly (good, 98 structures; fair, 2 structures).

CONCLUSIONS

A clinically available WB SiPM-PET scanner is useful for visualizing physiological FDG uptake in small brain nuclei, using a sufficiently high number of iterations for OSEM with TOF and PSF reconstructions.

PET/CT-aided biopsy of lung lesions enhances diagnostic efficacy, especially for lesions >3cm

Objectives

The purpose of this study was to compare the diagnostic efficacy of PET/CT-aided CT-guided and routine CT-guided transthoracic needle biopsy for lung lesions.

Methods

A total of 458 patients with suspicious lung lesions were referred for CT-guided biopsy, with 227 patients assigned to the PET/CT group and 231 patients assigned to the CT group. The clinical characteristics and diagnostic yield were compared between the two groups. Furthermore, conducting subgroup analysis to evaluate the differences of diagnostic success or failure between the two groups.

Results

The sensitivity and diagnostic accuracy rate differed significantly (P = 0.035, P = 0.048). In the PET/CT group, the values were 95.7% and 96.3%, respectively, while in the CT group, they were 90.1% and 91.9%. When considering non-diagnostic cases, the overall diagnostic success rate increased markedly in PET/CT group (93.0% vs. 83.1%, P = 0.001). In our subgroup analysis, the PET/CT group demonstrated superiority in detecting lesions larger than 3 cm (OR, 4.81; 95CI%, 2.03 - 11.36), while showing a moderate effect in lesions smaller than 3 cm (OR, 1.09; 95CI%, 0.42 - 2.81). Significant effect modification was observed in large lesions in the PET/CT group (P for interaction = 0.023).

Conclusions

18F-FDG-PET/CT enhances the diagnostic efficacy of CT-guided transthoracic needle biopsy for lung lesions, and the incremental value can be modified by lesion size, particularly when the diameter is larger than 3 cm.

The role of dynamic, static, and delayed total-body PET imaging in the detection and differential diagnosis of oncological lesions

OBJECTIVES

Commercialized total-body PET scanners can provide high-quality images due to its ultra-high sensitivity. We compared the dynamic, regular static, and delayed 18F-fluorodeoxyglucose (FDG) scans to detect lesions in oncologic patients on a total-body PET/CT scanner.

MATERIALS & METHODS

In all, 45 patients were scanned continuously for the first 60 min, followed by a delayed acquisition. FDG metabolic rate was calculated from dynamic data using full compartmental modeling, whereas regular static and delayed SUV images were obtained approximately 60- and 145-min post-injection, respectively. The retention index was computed from static and delayed measures for all lesions. Pearson's correlation and Kruskal-Wallis tests were used to compare parameters.

RESULTS

The number of lesions was largely identical between the three protocols, except MRFDG and delayed images on total-body PET only detected 4 and 2 more lesions, respectively (85 total). FDG metabolic rate (MRFDG) image-derived contrast-to-noise ratio and target-to-background ratio were significantly higher than those from static standardized uptake value (SUV) images (P < 0.01), but this is not the case for the delayed images (P > 0.05). Dynamic protocol did not significantly differentiate between benign and malignant lesions just like regular SUV, delayed SUV, and retention index.

CONCLUSION

The potential quantitative advantages of dynamic imaging may not improve lesion detection and differential diagnosis significantly on a total-body PET/CT scanner. The same conclusion applied to delayed imaging. This suggested the added benefits of complex imaging protocols must be weighed against the complex implementation in the future.

CLINICAL RELEVANCE

Total-body PET/CT was known to significantly improve the PET image quality due to its ultra-high sensitivity. However, whether the dynamic and delay imaging on total-body scanner could show additional clinical benefits is largely unknown. Head-to-head comparison between two protocols is relevant to oncological management.

Comparative evaluation of 11C-methionine and 18F-fluorodeoxyglucose positron emission tomography for distinguishing between primary central nervous system lymphoma and isocitrate dehydrogenase-wildtype glioblastoma

PURPOSE

Distinguishing between primary central nervous system lymphoma (PCNSL) and isocitrate dehydrogenase (IDH)-wildtype glioblastoma is important for therapeutic decision-making. This study aimed to compare the performance of 11C-methionine (MET) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for distinguishing between these two major malignant brain tumors.

METHODS

We retrospectively conducted qualitative and semiquantitative analyses of pre-treatment MET and FDG PET/computed tomography (CT) images of 22 patients with PCNSL and 64 patients with IDH-wildtype glioblastoma. For semiquantitative analysis, we calculated the tumor-to-normal tissue (T/N) ratio by dividing the maximum standardized uptake value (SUV) for the tumor (T) by the average SUV for the normal tissue (N). For performance evaluation, we employed receiver operating characteristic curve analysis and calculated the areas under the curve (AUC) values.

RESULTS

In the qualitative analysis, all PCNSLs and IDH-wildtype glioblastomas were MET-positive, while 95% and 84% of PCNSLs and IDH-wildtype glioblastomas, respectively, were FDG-positive. Eleven patients were excluded from the FDG PET/CT semiquantitative analysis because of hyperglycemia. There was no difference in MET T/N ratio between PCNSL and IDH-wildtype glioblastoma (p = 0.37). FDG T/N ratio was significantly higher in PCNSL than in IDH-wildtype glioblastoma (p < 0.001). The AUC value for distinguishing PCNSL from IDH-wildtype glioblastoma was significantly higher for the FDG T/N ratio (0.871) than for the MET T/N ratio (0.565) (p = 0.0027).

CONCLUSION

MET PET could detect both PCNSL and IDH-wildtype glioblastoma, but unlike FDG PET, it could not distinguish between these two major malignant brain tumors.

Primary Pulmonary Enteric Adenocarcinoma: Rare Imaging Findings

INTRODUCTION

Pulmonary enteric adenocarcinoma (PEAC) is an extremely rare variant of lung adenocarcinoma characterized by pathological features similar to those of colorectal adenocarcinoma. It is mostly observed on computed tomography (CT) and positron emission tomography (PET)/CT as solitary or multiple nodules/masses in the lung. It tends to grow rapidly and is difficult to distinguish from lung metastatic colorectal cancer. Herein, we have presented a case of PEAC with special imaging findings.

CASE PRESENTATION

A chest CT scan of a 72-year-old man with suspected chronic pneumonia revealed a well-defined consolidation in the upper lobe of the left lung. The lesion was slightly enlarged at the 9-month follow-up, and low FDG accumulation was subsequently observed using 18F-fluorodeoxyglucose (18F-FDG) PET/CT scans. The patient was later diagnosed with PEAC through percutaneous lung biopsy.

CONCLUSION

Our case has demonstrated specific imaging findings of PEAC.

The Diagnostic Value of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Differentiated Thyroid Cancer Patients with Elevated Thyroglobulin/Thyroglobulin Antibody Levels and Negative Iodine Scintigraphy: A Systematic Review and Meta-Analysis

Background: The objective of this study is to evaluate the diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in detecting recurrence in patients with differentiated thyroid cancer (DTC) who have negative whole-body scans (WBSs) but elevated serum thyroglobulin (Tg) or thyroglobulin antibody (TgAb) levels. Methods: This systematic review/meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Diagnostic Test Accuracy criteria (International Prospective Register of Systematic Reviews registration number: CRD42022340924). A comprehensive search of the MEDLINE, EMBASE, and Cochrane databases identified articles reporting the diagnostic accuracy of FDG PET/CT for the detection of recurrence in patients with DTC with negative WBS and elevated serum Tg or TgAb levels published between January 2012 and June 2023. Meta-analyses were performed to determine the diagnostic accuracy of FDG PET/CT on the total target population as well as on subgroups stratified by serum Tg or TgAb, and thyrotropin (TSH) stimulation status at the time of FDG PET/CT. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework was applied to evaluate the quality of evidence and the strength of recommendations to facilitate translation of the meta-analysis results into practical recommendations for clinical guidelines. Results: A total of 24 studies involving 1988 patients were included for analysis. The overall pooled sensitivity and specificity values were 0.87 (95% confidence interval [CI] = 0.83-0.92; I2 = 75%) and 0.84 (CI = 0.80-0.89; I2 = 44%), respectively. Subgroup analyses revealed no significant differences in the diagnostic accuracy of FDG PET/CT in patients stratified by serum Tg or TgAb levels, and TSH stimulation status at the time of PET/CT. Treatment plans were changed following FDG PET/CT imaging in 40% (CI = 34-47%; I2 = 39%) of cases. The quality level of evidence for using FDG PET/CT was moderate in both sensitivity and specificity according to the GRADE system. Conclusion: There is moderate quality evidence demonstrating the high diagnostic accuracy of FDG PET/CT in detecting recurrence in patients with DTC with negative WBS and elevated serum Tg or TgAb levels. This evidence corroborates the current guidelines' endorsement of FDG PET/CT as a diagnostic tool in such patients.

Isolated Solitary Asymptomatic Skeletal Muscle Relapse of High-Grade Lymphoma Detected on Surveillance 18F- Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography

While extranodal involvement of diffuse large B-cell lymphoma (DLBCL) is common, skeletal muscle involvement is extremely rare. Isolated skeletal muscle involvement in lymphoma is even rarer. We present here the case of a 26-year-old woman, who was diagnosed to have a solitary isolated skeletal muscle relapse of DLBCL on surveillance 18F-fluorodeoxyglucose positron emission tomography-computed tomography, after completing first-line treatment, that was subsequently confirmed with biopsy.

Automatic covariance pattern analysis outperforms visual reading of 18 F-fluorodeoxyglucose-positron emission tomography (FDG-PET) in variant progressive supranuclear palsy

BACKGROUND

To date, studies on positron emission tomography (PET) with 18 F-fluorodeoxyglucose (FDG) in progressive supranuclear palsy (PSP) usually included PSP cohorts overrepresenting patients with Richardson's syndrome (PSP-RS).

OBJECTIVES

To evaluate FDG-PET in a patient sample representing the broad phenotypic PSP spectrum typically encountered in routine clinical practice.

METHODS

This retrospective, multicenter study included 41 PSP patients, 21 (51%) with RS and 20 (49%) with non-RS variants of PSP (vPSP), and 46 age-matched healthy controls. Two state-of-the art methods for the interpretation of FDG-PET were compared: visual analysis supported by voxel-based statistical testing (five readers) and automatic covariance pattern analysis using a predefined PSP-related pattern.

RESULTS

Sensitivity and specificity of the majority visual read for the detection of PSP in the whole cohort were 74% and 72%, respectively. The percentage of false-negative cases was 10% in the PSP-RS subsample and 43% in the vPSP subsample. Automatic covariance pattern analysis provided sensitivity and specificity of 93% and 83% in the whole cohort. The percentage of false-negative cases was 0% in the PSP-RS subsample and 15% in the vPSP subsample.

CONCLUSIONS

Visual interpretation of FDG-PET supported by voxel-based testing provides good accuracy for the detection of PSP-RS, but only fair sensitivity for vPSP. Automatic covariance pattern analysis outperforms visual interpretation in the detection of PSP-RS, provides clinically useful sensitivity for vPSP, and reduces the rate of false-positive findings. Thus, pattern expression analysis is clinically useful to complement visual reading and voxel-based testing of FDG-PET in suspected PSP. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Chronic Inflammatory Demyelinating Polyradiculoneuropathy as a Presentation of Plasmacytoma

Polyneuropathy, organomegaly, endocrinopathy, M protein elevation, and skin changes (POEMS) syndrome is one of the rare paraneoplastic disorders of the multiorgan association whose initialism describes the principal clinical features as polyneuropathy, organomegaly, endocrinopathy, M-protein elevation, and skin changes caused by an underlying plasma cell disorder, one of the major diagnostic criteria for which is the presence of an osseous lesion. We present a case of POEMS syndrome with nearly all signs and symptoms on clinical and hematological examinations, which was further investigated with MRI of the whole spine and 18F-fluorodeoxyglucose positron emission tomography/computed tomography scan, as the latter is a very useful imaging modality for evaluation of any paraneoplastic syndromes, including myeloproliferative disorders such as plasmacytoma or multiple myeloma, and lymphoproliferative or other malignancies.

The effect of estrogen therapy on cerebral metabolism in diabetic female rats

The impact of estrogen on brain function, especially in individuals with diabetes, remains uncertain. This study aims to compare cerebral glucose metabolism levels in intact rats, ovariectomized (OVX) rats, and 17β-estradiol (E2)-treated OVX diabetic female rats. Sixteen rats were administered a single intraperitoneal injection of 70 mg/kg streptozotocin (STZ) to induce diabetes (intact, n = 6; OVX, n = 6; OVX+E2-treated, n = 4). Additionally, 18 rats received an equivalent solvent dose via intraperitoneal injection (intact, n = 6; OVX, n = 6; OVX+E2-treated, n = 6). After 4 weeks of STZ or solvent administration, positron emission tomography scans with 18F-fluorodeoxyglucose (18F-FDG) injection were employed to assess cerebral glucose metabolism. The diabetic rats exhibited substantial reductions in 18F-FDG uptake across all brain regions (all P < 0.01), in contrast to the control rats. Moreover, intact and OVX + E2-treated diabetic female rats displayed more pronounced decreases in cerebral glucose metabolism in the amygdala and hippocampus compared to OVX diabetic female rats (P < 0.05). These findings suggest that diabetes creates an environment wherein estrogen exacerbates neuropathology and intensifies neuronal activity.

The uptake of [18F]-fluorodeoxyglucose by the renal allograft correlates with the acute Banff scores of cortex inflammation but not with the 1-year graft outcomes

Introduction

[18F]FDG PET/CT noninvasively disproves acute kidney allograft rejection (AR) in kidney transplant recipients (KTRs) with suspected AR. However, the correlation of biopsy-based Banff vs. PET/CT-based scores of acute inflammation remains unknown, as does the prognostic performance of [18F]FDG PET/CT at one year post suspected AR.

Methods

From 2012 to 2019, 114 [18F]FDG-PET/CTs were prospectively performed in 105 adult KTRs who underwent per cause transplant biopsies. Ordinal logistic regression assessed the correlation between the extent of histological inflammation and the mean standardized [18F]FDG uptake values (mSUVmean). Functional outcomes of kidney allografts were evaluated at one year post per cause biopsy and correlated to mSUVmean.

Results

A significant correlation between mSUVmean and acute Banff score was found, with an adjusted R 2 of 0.25. The mSUVmean was significantly different between subgroups of "total i", with 2.30 ± 0.71 in score 3 vs. 1.68 ± 0.24 in score 0. Neither the function nor the survival of the graft at one year was statistically related to mSUVmean.

Discussion

[18F]FDG-PET/CT may help noninvasively assess the severity of kidney allograft inflammation in KTRs with suspected AR, but it does not predict graft outcomes at one year.

Development and External Validation of 18F-FDG PET-Based Radiomic Model for Predicting Pathologic Complete Response after Neoadjuvant Chemotherapy in Breast Cancer

The aim of our retrospective study is to develop and externally validate an 18F-FDG PET-derived radiomics model for predicting pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in breast cancer patients. A total of 87 breast cancer patients underwent curative surgery after NAC at Soonchunhyang University Seoul Hospital and were randomly assigned to a training cohort and an internal validation cohort. Radiomic features were extracted from pretreatment PET images. A radiomic-score model was generated using the LASSO method. A combination model incorporating significant clinical variables was constructed. These models were externally validated in a separate cohort of 28 patients from Soonchunhyang University Buscheon Hospital. The model performances were assessed using area under the receiver operating characteristic (AUC). Seven radiomic features were selected to calculate the radiomic-score. Among clinical variables, human epidermal growth factor receptor 2 status was an independent predictor of pCR. The radiomic-score model achieved good discriminability, with AUCs of 0.963, 0.731, and 0.729 for the training, internal validation, and external validation cohorts, respectively. The combination model showed improved predictive performance compared to the radiomic-score model alone, with AUCs of 0.993, 0.772, and 0.906 in three cohorts, respectively. The 18F-FDG PET-derived radiomic-based model is useful for predicting pCR after NAC in breast cancer.

Differentiating malignant and benign pleural effusion in patients with lung cancer: an 18F-FDG PET/CT retrospectively study

Rationale

To explore the clinical role of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in differentiating malignant pleural effusion (MPE) from benign pleural effusion (BPE) in patients with lung cancer.

Methods

Over a 8-year period, we retrospectively reviewed PET/CT data of lung cancer patients with pleural effusion, with 237 participants enrolled for analysis. The nature of pleural effusion was confirmed using pleural cytology or biopsy. MPE versus BPE comparison and multiple regression analysis were performed. Receiver operating characteristic (ROC) curve analysis was used for evaluating the diagnostic performance.

Results

Of the 237 participants, 170 had MPEs and 67 had BPEs. Compared with BPEs, MPEs had higher pleural SUVmax and thicker pleura and were more common among non-small cell lung cancers, peripheral tumors, and women (p < 0.05). BPEs had larger and higher ¹⁸F-FDG uptake thoracic lymph nodes and more complications of pneumonia (p < 0.05) than MPEs. Multiple regression analysis was used to identify the pleural SUVmax (odds ratio, OR = 38.8), sex (OR = 0.033), and mediastinal lymphoid node size (OR = 0.86) as independent risk factors for MPEs. The sensitivity, specificity, and area under the ROC curve (AUC) in the combined ROC curve analysis by using the three factors were 95.3%, 95.5%, and 0.989, respectively.

Conclusion

¹⁸F-FDG PET/CT integrated imaging is an effective non-invasive method for differential diagnosis of MPE in patients with lung cancer. Pleural SUVmax combined with thoracic lymph nodes and sex has high diagnostic value.

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

BACKGROUND

An 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 PRESENTATION

A 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.

CONCLUSION

PPM 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.

18F-fluorodeoxyglucose positron emission tomography findings of peripheral nerve sheath tumour of the nasal cavity in a dog

An 8-year-old Miniature Poodle presented with chronic sneezing and unilateral epistaxis. A left-sided intranasal mass was identified on computed tomography. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) was performed to evaluate the metabolic activity of the mass. The intranasal mass showed mildly increased 18F-FDG uptake. The maximal and mean standardized uptake values (SUVs) of the mass were 3.4 and 2.6, respectively. The maximal SUV of the mass/mean SUV of the normal liver was 2.5. The 7-cm soft, pink mass was easily removed through rhinoscopy, with subsequent dramatic improvement in clinical signs. Histopathological and immunohistochemical analyses determined that the mass was an intermediate-grade malignant peripheral nerve sheath tumour (PNST). This is the first report of 18F-FDG PET findings in a PNST in dogs.