ESR Essentials: role of PET/CT in neuroendocrine tumors-practice recommendations by the European Society for Hybrid, Molecular and Translational Imaging.

Neuroendocrine neoplasms (NEN) originate from the secretory cells of the neuroendocrine system, with the majority arising in the gastrointestinal tract and pancreas. Given the heterogeneity in the biological behavior and morphological differentiation of these tumors, advanced imaging techniques are crucial for supporting the suspected diagnosis, accurate staging, and monitoring therapy. As most well-differentiated NEN demonstrate overexpression of somatostatin receptors (SSR) on the cell surface, SSR-directed PET/CT is considered the reference standard for imaging of this particular entity. SSR-PET/CT should be the imaging method of choice in every NEN G1 or G2 and considered for re-staging after both potentially curative and non-curative surgeries. The extent of SSR expression is also crucial for determining a patient's eligibility for peptide receptor radionuclide therapy (PRRT). PRRT utilizes [177Lu]Lu-DOTA-TATE to target the SSR receptor and can significantly prolong progression-free survival in patients with advanced, progressive neuroendocrine tumor of the gastroenteropancreatic system (GEP-NET). PET/CT is a central component of the multidisciplinary management of NEN. Variable follow-up intervals are recommended, considering that tumors with higher proliferation rates or advanced metastatic disease require more frequent assessments. The combination with other imaging modalities, like MRI, complements SSR-PET/CT, further enhancing overall diagnostic accuracy. KEY POINTS: Somatostatin receptor-PET/CT (SSR-PET/CT) is the guideline-recommended reference standard for imaging well-differentiated neuroendocrine tumors (NET). SSR-PET/CT should be the diagnostic imaging of choice for staging and post-therapy re-staging of grade 1 or 2 NET (G1 or G2). Variable follow-up intervals are recommended for NET G1 and G2. Tumors with higher proliferation rates or advanced metastatic disease necessitate more frequent assessments.

Testicular Incidentaloma on 18F-choline PET/CT in a Patient with Prostatic Adenocarcinoma.

Prostatic adenocarcinoma is characterized by elevated phosphatidylcholine metabolism. 18F-choline positron emission tomography/computed tomography (PET/CT) is widely used for patients with biochemical recurrence and a prostate-specific antigen threshold above 2 ng/mL. We report a case of a patient with high-risk prostatic adenocarcinoma undergoing 18F-choline PET/CT for biochemical recurrence. In addition to hypermetabolic abdominal lymph nodes, an unexpected right testicular hypermetabolism was observed. Such findings on 18F-choline PET/CT may suggest a primary tumor or testicular metastasis of prostate cancer. Bilateral orchiectomy revealed a vitelline tumor associated with known primary prostatic cancer. The incidental discovery of a testicular vitelline tumor during prostate cancer imaging is rare, highlighting the importance of thorough diagnostics. This case underscores the need for comprehensive care in managing complex and atypical cancer cases, emphasizing the potential for unrelated tumor discoveries during diagnostic workup. Further research is essential for a better understanding of these rare co-occurring cancers and their treatment implications.

Outstanding increase in tumor-to-background ratio over time allows tumor localization by [89Zr]Zr-PSMA-617 PET/CT in early biochemical recurrence of prostate cancer.

BACKGROUND: Positron emission tomography/computed tomography (PET/CT) using prostate-specific membrane antigen (PSMA)-targeted radiotracers labeled with zirconium-89 (89Zr; half-life ~ 78.41 h) showed promise in localizing biochemical recurrence of prostate cancer (BCR) in pilot studies. METHODS: Retrospective analysis of 38 consecutive men with BCR (median [minimum-maximum] prostate-specific antigen 0.52 (0.12-2.50 ng/mL) undergoing [89Zr]Zr-PSMA-617 PET/CT post-negative [68Ga]Ga-PSMA-11 PET/CT. PET/CT acquisition 1-h, 24-h, and 48-h post-injection of a median (minimum-maximum) [89Zr]Zr-PSMA-617 tracer activity of 123 (84-166) MBq. RESULTS: [89Zr]Zr-PSMA-617 PET/CT detected altogether 57 lesions: 18 local recurrences, 33 lymph node metastases, 6 bone metastases in 30/38 men with BCR (78%) and prior negative conventional PSMA PET/CT. Lesion uptake significantly increased from 1-h to 24-h and, in a majority of cases, from 24-h to 48-h. Tumor-to-background ratios significantly increased over time, with absolute increases of 100 or more. No side effects were noted. After [89Zr]Zr-PSMA-617 PET/CT-based treatment, prostate-specific antigen concentration decreased in all patients, becoming undetectable in a third of patients. LIMITATIONS: retrospective, single center design; infrequent histopathological and imaging verification. CONCLUSION: This large series provides further evidence that [89Zr]Zr-PSMA-617 PET/CT is a beneficial imaging modality to localize early BCR. A remarkable increase in tumor-to-background ratio over time allows localization of tumor unidentified on conventional PSMA PET/CT.

ESR Essentials: staging and restaging with FDG-PET/CT in oncology-practice recommendations by the European Society for Hybrid, Molecular and Translational Imaging.

Positron emission tomography (PET) stands as the paramount clinical molecular imaging modality, especially in oncology. Unlike conventional anatomical-morphological imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI), PET provides detailed visualizations of internal activity at the molecular and cellular levels. 18-fluorine-fluorodeoxyglucose ([18F]FDG)-PET combined with contrast-enhanced CT (ceCT) significantly improves the detection of various cancers. Appropriate patient selection is crucial, and physicians should carefully assess the appropriateness of [18F]FDG-PET/CT based on specific clinical criteria and evidence. Due to its high diagnostic accuracy, [18F]FDG-PET/CT is indispensable for evaluating the extent of disease, staging, and restaging known malignancies, and assessing the response to therapy. PET/CT imaging offers significant advantages in patient management, particularly by identifying occult metastases that might otherwise go undetected. This can help prevent unnecessary surgeries, allowing many patients to be redirected to systemic chemotherapy instead. However, it is important to note that the gold standard for surgical planning remains CT and/or MRI, depending on the body region. These imaging modalities, with or without associated angiography, provide superior contrast and spatial resolution, essential for detailed surgical preparation and planning. [18F]FDG-PET/CT has a central role in the precise and early diagnosis of cancer, contributing significantly to personalized treatment plans. However, it has limitations, including non-tumor-specific uptake and the potential to inaccurately capture the metabolic activity of certain tumor types due to low uptake in some well-differentiated tumor cell lines. Therefore, it should be utilized in clinical scenarios where it offers crucial diagnostic insights not readily available with other imaging modalities. KEY POINTS: Use [18F]FDG-PET/CT selectively based on clinical appropriateness criteria and existing evidence to optimize resource utilization and minimize patient exposure. Employ [18F]FDG-PET/CT in treatment planning and monitoring, particularly for assessing chemotherapy or radiotherapy response in FDG-avid lymphoma and solid tumors. When available, [18F]FDG-PET/CT can be integrated with other diagnostic tools, such as MRI, to enhance overall diagnostic accuracy.

A challenging diagnosis of prostate cancer seeding in the perineal needle-tract after transperineal biopsy: is PET-CT the imaging of choice?

Perineal seeding is an extremely rare complication after prostate biopsy. We found a perineal localization of prostatic adenocarcinoma 5 years after the transperineal biopsy in a patient with metastatic castration resistant prostate cancer. The tumor was identified by a18F-Fluorocholin positron emission tomography-computed tomography (18F-FCH PET-CT) performed after a sudden rise of PSA levels during androgen deprivation therapy and after a negative CT scan. This case report underscores the challenge one may encounter in detecting perineal prostate cancer metastasis after a biopsy when using traditional imaging with CT scan alone or MRI, and the added diagnostic value of PET-CT imaging.

Incidental detection of pancreatic cancer by F-18-fluorodeoxyglucose positron emission tomography/computed tomography in a patient with hereditary breast and ovarian cancer syndrome.

Patients with hereditary breast and ovarian cancer syndrome (HBOC) are associated with an increased risk of developing pancreatic cancer (PC) than the general population. There is no consensus about the clinical value of F-18-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in patients with HBOC. We report a patient with HBOC in whom PC was detected incidentally by PET/CT. A 48-year-old woman complaining of a right breast mass sought evaluation at our hospital. Her older brother died of PC at 49 years of age. Histologic analysis of the breast mass revealed breast cancer (BC). FDG-PET/CT showed unanticipated FDG accumulation in the pancreas. Magnetic resonance cholangiopancreatography (MRCP) revealed a mass in the pancreas approximately 25mm in size. Endoscopic ultrasound guided-fine needle aspiration biopsy (EUS-FNA) demonstrated PC. Genetic testing showed a BRCA2 pathologic variant [NM_000059.4(BRCA2): c.9076C > T (p.Gln3026Ter)]. She was referred to a university hospital and underwent surgery after neoadjuvant chemotherapy for PC. It is difficult to detect operable PC in most patients. The diagnostic utility of PET/CT for PC in high-risk patients, such as those with HBOC, is undetermined. Our case has demonstrated the clinical value of PET/CT in detecting incidental PC in HBOC patients.

[Application of 18F-FDG PET/CT in rheumatic diseases].

OBJECTIVE: To explore the application of 18F-flurodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in rheumatic diseases, to compare these different imaging features, and to describe the current PET/CT imaging status in clinical practice. METHODS: A total of 486 cases in our department from January 2012 to December 2018 were enrolled in this study, and 18F-FDG PET/CT examination was performed in all the patients. The clinical use of 18F-FDG PET/CT was retrospectively analyzed to discuss the clinical application and its imaging characteristics of rheumatic diseases. Categorical data were used to ascertain prevalence statistics, whereas continuous data were used to delineate means and standard deviations. Independent sample t test, Chi square test and Mann-Whitney U test were used for statistical analysis. A P-value of < 0.05 was considered significant. RESULTS: (1) From 2012 to 2018, totally 486 patients in the Department of Rheumatology and Immunology underwent 18F-FDG PET/CT examination, accounting for 5.30% of the total number of PET/CT examinations in the whole hospital. In this study, 304 of the 486 patient were female (62.55%), 182 of them were male (37.45%), the average age of the patients was (53.21±18.81) years, and the proportion of the patients aged 45-65 (227/486, 46.71%) was the highest group. (2) Three leading purposes of the PET/CT examination in our department were to exclude cancers (55.56%), assist in diagnosis (24.60%) and evaluate the disease activity (19.84%). (3) Of the 486 patients who underwent 18F-FDG PET/CT, 327 cases might indicate a differential diagnosis of rheumatic disease, of which, 292 cases were highly suggestive of diagnosis, including 61 cases of myositis, 60 cases of vasculitis, 37 cases of adult still's disease, 32 cases of IgG4 related diseases, 30 cases of rheumatoid arthritis, 22 cases of Sjögren's syndrome, 22 cases of systemic lupus erythematosus, and 9 cases of rheumatic polymyalgia; the remaining 35 cases only prompted the possibility of autoimmune disease. Of the 486 patients, 74 cases suggested the diagnosis of cancers, 25 cases indicated the diagnosis of infectious diseases, while 60 cases could not show any diagnostic values. Ten patients with rheumatic disease were followed up with a post-treatment repeat PET/CT, and the findings in remission showed reduced 18F-FDG metabolic activity as well as a reduction in the extent of metabolic hypertrophic lesions. CONCLUSION: There are some typical sign of 18F-FDG PET/CT for diffuse connective tissue diseases, therefore 18F-FDG PET/CT has auxi-liary effect on the classification diagnosis of rheumatic diseases, especially for the exclusion of cancers.

Unveiling the Silent Menace: A Case Report of Extrapulmonary Tuberculosis Masquerading as Neuroendocrine Tumor With a Brief Review of the Literature.

We present the case of a 59-year-old man from South India who presented with shortness of breath, abdominal distention, and decreased appetite. Initial laboratory investigations and imaging, including radiolabeled somatostatin positron emission tomography-computed tomography, were suggestive of neuroendocrine tumor (NET). However, following extensive workup and multiple biopsies over several weeks, the diagnosis was revised to extrapulmonary tuberculosis (EPTB). This case highlights the diagnostic challenge of distinguishing between NET and EPTB. We also review varying literature on the pathogenesis and similarities between these two conditions, discuss the role of laboratory investigations and imaging in identifying overlapping findings, and compare the diagnostic modalities used for NET and EPTB.

CEUS compared with CECT, MRI, and FDG-PET/CT for diagnosing CRC liver metastases: a diagnostic test accuracy systematic review and meta-analysis.

OBJECTIVE: To determine the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) compared with contrast-enhanced computed tomography (CECT), magnetic resonance imaging (MRI), and Fluorine-18-deoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for diagnosing suspected liver metastases in patients with newly diagnosed colorectal cancer (CRC). METHODS: The meta-analysis using the bivariate model included studies on patients with newly diagnosed CRC only and excluded patients with non-CRC liver metastases, known liver metastases, patients treated with chemotherapy and local treatments, e.g. hepatic resection or radiofrequency ablation. We used QUADAS-2 to assess the methodological quality of the studies. RESULTS: We included 32 studies, 6 studies evaluated the accuracy of CEUS (n = 937 participants), 26 studies evaluated CECT (n = 2,582), 8 studies evaluated MRI (n = 564) and 6 studies evaluated FDG-PET/CT (n = 813). Sensitivity: FDG-PET/CT 94.4% [95% CI: 90.7-98.1%], MRI 92.9% [95% CI: 88.8-97.0%], CEUS 86.1% [95% CI: 78.0-94.3%] and CECT 84.6% [95% CI: 79.3-89.9%]. Specificity FDG-PET/CT 97.9% [95% CI: 95.9-99.9%], CEUS 96.1% [95% CI: 93.6-98.6%], MRI 94.4% [95% CI: 90.5-98.3%], and CECT 94.3% [95% CI: 91.8-96.8%]. CONCLUSION: FDG-PET/CT had significantly higher sensitivity and specificity than CECT, and significantly higher sensitivity than CEUS. MRI had a significantly higher sensitivity than CEUS, but a lower non-significant specificity. CECT had the lowest sensitivity and specificity. PROSPERO REGISTRATION DETAILS: CRD42017055015 and CRD42017082996.

Imaging features of hepatic angiosarcoma: retrospective analysis of two centers.

PURPOSE: Identifying primary hepatic angiosarcoma (PHA) preoperatively is challenging, often relying on postoperative pathology. Invasive biopsy increases bleeding risk, emphasizing the importance of early PHA diagnosis through imaging. However, comprehensive summaries of ultrasound, abdominal computed tomography (CT), magnetic resonance imaging (MRI), and whole- body positron emission tomography-CT (PET-CT) in this context are lacking. This study aimed to investigate the comprehensive imaging characteristics of PHA. PATIENTS AND METHODS: Imaging data were collected from 7 patients diagnosed with PHA via pathology between January 2000 and December 2019 in two provincial grade III hospitals. All patients underwent routine color ultrasound examinations before surgery, with 3 patients receiving contrast-enhanced ultrasound (CEUS).CT scans, both plain and enhanced, were performed on 5 patients, and whole-body PET-CT examinations were conducted on 2 patients. RESULTS: Among the 7 patients with PHA, 4 presented with a single solid intrahepatic mass (2 of which were large), 1 with a single exophytic macroblock type, 1 with a mixed type featuring multiple masses and nodules, and 1 with a multiple nodule type. Conventional ultrasound of PHA showed uneven echoes within the tumor, potentially accompanied by septal zone echoes, and a blood flow grade of 0-I. CEUS displayed early-stage circular high enhancement, a central non-enhancement area, and a "vascular sign" around the tumor. CT scans revealed low-density shadows in the plain scan stage, high peripheral ring enhancement, and punctate nodular enhancement in the arterial phase, with varying intensities and the presence of a "vascular sign." During the portal vein stage, the interior of the tumor was consistently unfilled and exhibited structural disorder. PET-CT showed low-density lesions in the liver and low fluorodeoxyglucose metabolism. CONCLUSIONS: Imaging diagnosis plays a crucial role in PHA diagnosis. When liver tumor imaging matches the above characteristics, consider PHA.

Pathologic Validation of Deauville Score-Based Disease on F-18 FDG PET/CT after First-Line Treatment in Patients with Lymphoma.

Purpose: PET/CT-based Deauville scoring (DS) is routinely used for lymphoma response assessment. However, pathological correlation of DS is not yet precisely documented. In the present study we aimed to pathological confirm the PET/CT-based Deauville scoring (DS) in lymphoma after first-line chemotherapy. Materials and methods: Participants undergoing PET/CT for response assessment following first-line treatment were recruited prospectively. DS ≥ 4 lesions were interpreted as PET-positive, while DS ≤ 3 as PET-negative. Participants with a PET-positive lesion or suspicious of inadequate response (DS ≤ 3) were recruited for metabolic core-needle biopsy. True-negative and benign histopathology were kept on follow-up for three months. Histopathological, clinical and imaging findings were assessed for diagnostic performance. Procedure-related complications were also noted. Results: In all, 148/480 participants were PET-positive, and 332/480 were PET-negative. 138/148 PET-positive and 12/332 PET-negative lesions were recruited for biopsy. Biopsy was performed in 147/150 participants (PET-positive 135; PET-negative 12). Three patients with inaccessible lesions were excluded. The diagnostic yield of the procedure was 97.3% (143/147). Histology revealed lymphoma in 106 participants (including 70% of total DS-4, 100% of DS-5a and 73.9% of DS-5b lesions), with three false-negative lesions. DS ≤ 3 lesions were true-negative except one diagnosed with lymphoma (8.3%) on follow-up. Non-lymphomatous malignancies (n = 5), granulomas (n = 12), non-specific inflammation (n = 9) and no residual disease (n = 11) were diagnosed in the rest. No major procedure-related adverse event was noted. Conclusion: A DS-5a lesion suggests residual disease; hence, a biopsy can be prevented unless Richter's transformation is suspected. DS-4 and DS-5b lesions require a biopsy before changing the treatment plan, as a certain number of participants had non-lymphomatous F-18 FDG-avid lesions.

Better survival with lobectomy versus sublobar resection in patients with hypermetabolic c-stage IA lung cancer on positron emission tomography/computed tomography.

OBJECTIVES: The clinical trial showed that sublobar resection was not inferior to lobectomy in terms of disease-free survival in patients with peripherally located non-small-cell lung cancer ≤2 cm. However, it is not clear whether sublobar resection is indicated for all types of c-stage IA lung cancer. The purpose of this study was to clarify whether sublobar resection is indicated for c-stage IA hypermetabolic lung cancer. METHODS: Patients with c-stage IA lung cancer who underwent F-18 fluorodeoxyglucose positron emission tomography/computed tomography and lobectomy or sublobar resection were assessed. Of these, patients who had a maximum standardized uptake value ≥3.0 on positron emission tomography/computed tomography were evaluated. We compared survival rates after lobectomy versus sublobar resection. Propensity score matching was performed to balance patient characteristics between groups. RESULTS: Between April 2004 and March 2023, 723 patients underwent lobectomy or sublobar resection and had a maximum standardized uptake value ≥3.0 on positron emission tomography/computed tomography. Lobectomy and sublobar resection were performed in 532 (73.6%) and 191 (26.4%) patients, respectively. Both the 5-year overall and disease-free survival rates were worse after sublobar resection compared with lobectomy (62.3% vs 79.9% and 53.9% vs 70.3%, respectively). After propensity score matching, the 5-year overall and disease-free survival rates remained worse after sublobar resection compared with lobectomy (60.7% vs 75.2% and 51.6% vs 67.7%, respectively). CONCLUSIONS: Patients with c-stage IA hypermetabolic lung cancer with standardized uptake value ≥3.0 on positron emission tomography/computed tomography had a worse prognosis after sublobar resection than after lobectomy.

Prognostic significance of diffuse increased fluorine-18-fluorodeoxyglucose (18F-FDG) uptake within the reticuloendothelial system in lymphoma patients.

Background: As constituents of the reticuloendothelial system, the spleen and bone marrow (BM) have been recognized as integral components of the systemic inflammatory response in cancer contexts, thereby serving as predictive indicators for assessing cancer prognosis. Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) has attained widespread utilization for staging, assessing treatment response, and prognostication in lymphoma patients. Several investigations have proposed that focal increased 18F-FDG uptake in the BM or spleen may correlate with malignant involvement in lymphoma. However, scant data exist regarding the implications of diffuse BM and splenic uptake. This study aimed to explore the relationships between metabolic parameters of the spleen and BM on 18F-FDG PET/CT and inflammatory markers, and to assess their prognostic value in patients with lymphoma. Methods: A retrospective analysis was conducted on 118 patients newly diagnosed with malignant lymphoma, who underwent 18F-FDG PET/CT and exhibited diffuse increased splenic or BM uptake in 18F-FDG PET/CT imaging. The mean standardized uptake value (SUV) of the spleen, BM, and liver was calculated. The association between metabolic variables and systemic inflammatory markers was investigated, and the prognostic significance of clinicopathological and PET parameters was assessed using overall survival (OS) and progression-free survival (PFS). Results: A statistically significant correlation was found between the spleen-to-liver SUV ratio (SLR) and inflammatory markers such as C-reactive protein (r=0.264, P=0.007) and platelet-to-lymphocyte ratio (r=0.227, P=0.021). No significant correlation was observed between BM-to-liver SUV ratio (BLR) and hematologic parameters, while concordance analysis revealed a fair agreement between BLR and bone marrow biopsy (BMB) (Cohen's Kappa-κ =0.271, P=0.002). In patients with aggressive non-Hodgkin lymphoma, both SLR [P=0.017, HR 2.715, 95% confidence interval (CI): 0.875-8.428] and BLR (P=0.044, HR 0.795, 95% CI: 0.348-1.813) were significantly linked to OS, while SLR (P=0.019, HR 2.223, 95% CI: 1.139-4.342) emerged as a significant prognostic factor for PFS. Conclusions: This study highlighted that diffuse increased splenic 18F-FDG uptake in lymphoma patients was closely associated with inflammation, whereas diffuse BM uptake was likely attributable to BM infiltration rather than inflammatory changes. Furthermore, both parameters held promise as prognostic indicators for patients with aggressive lymphoma.

Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) combined with conventional MRI for the detection of skull-base invasion in nasopharyngeal carcinoma: comparison with 18F-sodium fluoride (18F-NaF) positron emission tomography/computed tomography (PET/CT).

Background: The extent of skull base invasion (SBI) in nasopharyngeal carcinoma (NPC) directly impacts tumor staging, treatment strategies, and prognosis assessment for NPC patients, emphasizing the critical need for prompt diagnosis and precise assessment of invasion. Thus, we aimed to integrate the advantages of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and conventional magnetic resonance imaging (cMRI), and assess their combined diagnostic efficacy versus that of 18F-sodium fluoride (18F-NaF) positron emission tomography/computed tomography (PET/CT) for detecting SBI in NPC patients. Methods: The study prospectively and randomly recruited 62 patients newly diagnosed with NPC by pathological biopsy at the Cancer Center of Affiliated Hospital of Guangdong Medical University from January 2021 to September 2022. All patients underwent baseline cMRI, IVIM-DWI, and PET/CT scans. The IVIM-DWI analysis included 3 primary parameters: true diffusion coefficient (D), pseudodiffusion coefficient (D*), and pseudodiffusion fraction (f). SBI was defined as the involvement of any substructure confirmed by follow-up MRI and clinical symptoms. Inter-observer agreement was evaluated utilizing the intraclass correlation coefficients (ICC) and kappa coefficients. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic performance of cMRI, IVIM-DWI plus cMRI, and PET/CT. DeLong test was used to compare the areas under the curve (AUC) of the 3 modalities. Results: Excellent inter-observer reliability was observed (range, 0.841-0.946). Among the IVIM-DWI parameters, D* + f demonstrated comparable accuracy to D + D* + f (AUC 0.906 vs. 0.904; sensitivity 88.9% vs. 89.8%; specificity 92.3% vs. 91.0%). IVIM-DWI plus cMRI yielded an overall AUC of 0.947, sensitivity of 92.6%, and specificity of 96.8%, surpassing cMRI alone with an AUC of 0.914 (P=0.025), sensitivity of 91.2%, and specificity of 91.7%, as well as 18F-NaF PET/CT with an AUC of 0.852 (P<0.001), sensitivity of 80.1%, and specificity of 90.4%. In detecting substructures of SBI, IVIM-DWI plus cMRI showed superior performance compared to 18F-NaF PET/CT within the petrous part of the temporal bone (AUC 0.968 vs. 0.871, P=0.011; sensitivity 93.5% vs. 87.1%, specificity 100% vs. 87.1%), pterygopalatine fossa (AUC 0.935 vs. 0.831, P=0.032; sensitivity 93.9% vs. 69.7%, specificity 93.1% vs. 96.6%), and foramen ovale (AUC 0.885 vs. 0.710, P=0.019; sensitivity 76.9% vs. 61.5%, specificity 100% vs. 80.6%). Conclusions: IVIM-DWI plus cMRI can accurately detect SBI and the substructures in NPC, providing a valuable reference for personalized treatment strategies and precise prognosis assessment.

Negative-predictive value of SUVmax for Ascertaining the efficacy of osimertinib in EGFR mutation-positive non-small cell lung cancer.

BACKGROUND: Fluorine-18 2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) is routinely used to stage non-small cell lung cancer (NSCLC). However, whether 18F-FDG accumulation in primary tumors affects the efficacy of osimertinib in patients with epidermal growth factor receptor (EGFR) mutation-positive NSCLC remains unclear. METHODS: We retrospectively investigated 74 patients with advanced or postoperative recurrent EGFR mutation-positive NSCLC who underwent 18F-FDG PET/CT and were treated with osimertinib as first-line therapy between September 2018 and March 2023 at Kumamoto University Hospital. The maximum standardized uptake value (SUVmax) of each primary tumor was measured, and the patients were divided into two groups according to the median SUVmax. The effects of SUVmax on progression-free survival (PFS) and overall survival (OS) were assessed using a multivariate Cox proportional hazards model. RESULTS: The median SUVmax was 8.2 (interquartile range: 5.5-11.4). The median PFS in the high SUVmax group (≥8.2) was significantly shorter than that in the low SUVmax group (<8.2). The respective median PFSs were 11.2 months (95% confidence interval [CI]: 3.1-19.3 months) vs. 22.9 months (95% CI: 12.4-33.4 months) (P = 0.015), although the OS values did not differ significantly. Multivariate analysis showed that a high SUVmax was an independent negative predictive factor for PFS in patients treated with osimertinib (hazard ratio, 2.25; 95% CI: 1.15-4.39, P = 0.017). CONCLUSIONS: High primary-lesion SUVmax in patients with EGFR mutation-positive NSCLC correlated with shorter PFS with first-line osimertinib therapy, suggesting that SUVmax is a useful predictive marker for the antitumor efficacy of osimertinib.

An Analysis of Age-Related Body Composition Changes and Metabolic Patterns in Korean Adults Using FDG-PET/CT Health Screening Data.

Background: F-18-fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) can be used to measure bone mineral density (BMD), cross-sectional muscle area (CSMA), Hounsfield units (HU) of liver and muscle, subcutaneous adipose tissue (SAT), abdominal visceral adipose tissue (VAT), and glucose metabolism. The present study aimed to identify age-related changes in body composition and glucose metabolism in Korean using opportunistic FDG-PET/CT imaging. Methods: We analyzed FDG-PET/CT, clinical history, and laboratory data abstracted from the medical records of patients who underwent health screening at a single institute between 2017 and 2022. Results: In total, 278 patients were included in the analysis (male:female=140:138). Age and body mass index were positively correlated in female, but negatively correlated in male. BMD decreased with age more in female, and CSMA decreased with age more in male. Muscle HU decreased with age for both sexes. In female, SAT and VAT increased with age; and in male, SAT decreased slightly while VAT remained stable. Muscle glucose metabolism showed no association with age in male but increased with age in female. CSMA correlated positively with BMD overall; and positively correlated with VAT and SAT in male only. In female only, both SAT and VAT showed negative correlations with glucose metabolism and correlated positively with muscle glucose metabolism. Liver HU values were inversely correlated with VAT, especially in female; and positively correlated with muscle glucose metabolism in female only. Conclusion: FDG-PET/CT demonstrated distinct patterns of age-related changes in body composition and glucose metabolism, with significant differences between sexes.

Applying deep learning-based ensemble model to [18F]-FDG-PET-radiomic features for differentiating benign from malignant parotid gland diseases.

OBJECTIVES: To develop and identify machine learning (ML) models using pretreatment 2-deoxy-2-[18F]fluoro-D-glucose ([18F]-FDG)-positron emission tomography (PET)-based radiomic features to differentiate benign from malignant parotid gland diseases (PGDs). MATERIALS AND METHODS: This retrospective study included 62 patients with 63 PGDs who underwent pretreatment [18F]-FDG-PET/computed tomography (CT). The lesions were assigned to the training (n = 44) and testing (n = 19) cohorts. In total, 49 [18F]-FDG-PET-based radiomic features were utilized to differentiate benign from malignant PGDs using five different conventional ML algorithmic models (random forest, neural network, k-nearest neighbors, logistic regression, and support vector machine) and the deep learning (DL)-based ensemble ML model. In the training cohort, each conventional ML model was constructed using the five most important features selected by the recursive feature elimination method with the tenfold cross-validation and synthetic minority oversampling technique. The DL-based ensemble ML model was constructed using the five most important features of the bagging and multilayer stacking methods. The area under the receiver operating characteristic curves (AUCs) and accuracies were used to compare predictive performances. RESULTS: In total, 24 benign and 39 malignant PGDs were identified. Metabolic tumor volume and four GLSZM features (GLSZM_ZSE, GLSZM_SZE, GLSZM_GLNU, and GLSZM_ZSNU) were the five most important radiomic features. All five features except GLSZM_SZE were significantly higher in malignant PGDs than in benign ones (each p < 0.05). The DL-based ensemble ML model had the best performing classifier in the training and testing cohorts (AUC = 1.000, accuracy = 1.000 vs AUC = 0.976, accuracy = 0.947). CONCLUSIONS: The DL-based ensemble ML model using [18F]-FDG-PET-based radiomic features can be useful for differentiating benign from malignant PGDs. The DL-based ensemble ML model using [18F]-FDG-PET-based radiomic features can overcome the previously reported limitation of [18F]-FDG-PET/CT scan for differentiating benign from malignant PGDs. The DL-based ensemble ML approach using [18F]-FDG-PET-based radiomic features can provide useful information for managing PGD.

Mediastinal Hemangioma Mimicking as Bronchial NET.

We present a rare case of mediastinal capillary hemangioma in a 54-year-old female. She presented with back pain in the left suprascapular region, and the chest radiograph revealed left pleural effusion. On further workup with high-resolution computed tomography (CT) chest, a hypervascular pleural-based neoplastic lesion in the left upper hemithorax with gross left pleural effusion and subtotal collapse of the left lung was identified. 18F-fluorodeoxyglucose positron emission tomography/CT was suggestive of a weakly metabolic well-defined pleural-based soft tissue lesion in the left upper hemithorax along the mediastinal side. Neuroendocrine tumor was suspected. 68Ga-DOTATATE PET/CT was advised, which showed intense uptake in the lesion. The mass was resected completely. Histopathological examination established the final diagnosis as benign vascular tumor consistent with a capillary hemangioma.

An Unusual Occurrence of Metastases to Multiple Muscles in Neuroblastoma.

Neuroblastoma presenting with multiple muscles and subcutaneous tissue metastases is rarely reported in the literature. We would like to highlight such infrequent occurrences for increasing the clinical acumen of the medical fraternity with an aim to deliver proper therapy to patients.

An Analysis of the Diagnostic Performance of Tc-99m PSMA SSPECT/CT in Biochemically Recurrent Prostate Cancer Compared with Ga-68 PSMA PET/CT: A Single-center, Prospective Study.

Objective: Biochemical recurrence (BCR) after initial management of Prostate Carcinoma (PC) is frequent. Subsequent interventions rely on disease burden and metastasis distribution. 68Ga prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) is an excellent imaging modality in BCR. However, 68Ga is radionuclide generator produced and has restricted availability. 99mTc-labeled PSMA could be a potential cost-effective alternative. We compared the performance of 99mTc-PSMA single-photon emission CT (SPECT)/CT and 68Ga-PSMA PET/CT in BCR with a serum prostate surface antigen (PSA) level of <20 ng/mL. Materials and Methods: The prospective study included 25 patients with BCR and at least one lesion on a 68Ga-PSMA PET/CT. All patients underwent 99 mTc-PSMA SPECT/CT, and disease distribution and metastatic burden were compared with 68Ga-PSMA PET/CT. The maximum standard uptake value (SUVmax) and the tumor-to-background ratio (TBR) were computed and analyzed. Results: The mean age and serum PSA (SPSA) were 69.72 ± 6.69 years and 5.65 ± 6.07 ng/mL. Eleven patients (44%) had SPSA ≤2 ng/mL. Recurrent sites were noted in the prostate (19, 76%), prostatic bed (3, 12%), and pelvis lymph nodes (LNs) (13, 52%). Distant metastasis to bones (13, 52%), lungs (5, 20%), and retroperitoneal LNs (2, 8%) were noted. Both modalities were concordant for the recurrent disease at the prostate, prostatic bed, bone, and lung lesions. 99mTc-PSMA could localize pelvis LNs in most patients (10/13, 76.9%). The site-specific sensitivity and specificity between the two modalities were not significantly different (P > 0.05). TBR shows excellent correlation with SUVmax (0.783, P < 0.001). Four (16%) patients were understaged with 99mTc-PSMA due to the nonvisualization of the subcentimeter size LNs. No patient with systemic metastases was understaged. Conclusions: 99mTc-PSMA SPECT/CT has good concordance with 68Ga-PSMA PET/CT in BCR, even at low PSA levels. However, it may miss a few subcentimeter LNs due to lower resolution. 99mTc-PSMA SPECT/CT could be a simple, cost-effective, and readily available imaging alternative to PET/CT.