Venous tumor thrombus is a rare complication of rectal cancer but is more common in other types of cancer, like renal cell carcinoma and hepatocellular carcinoma. The usual site of tumor thrombus in rectal cancer patients is the inferior mesenteric vein (IMV), which is seldom seen in the common iliac vein, with only a few cases reported till now. We present a case of fluorodeoxyglucose (FDG) avid right iliac vein tumor thrombosis after low anterior resection in a patient with rectal cancer and review the literature.

F18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) plays a crucial role in tumour diagnosis, staging, and therapy response evaluation of various cancer types and has been a standard imaging modality used in clinical oncology practice for many years. However, it has certain limitations in evaluating some particular gastrointestinal cancer types due to low FDG-avidity or interphering physiological background activity. Fibroblast activation protein (FAP), a protein of the tumour microenvironment, is overexpressed in a wide range of cancers which makes it an attractive target for both tumour imaging and therapy. Recently, FAP-targeted radiopharmaceuticals are widely used in clinical research and achieved great results in tumour imaging. Considering the limitations of FDG PET/CT and the lack of physiological FAP-targeted tracer uptake in liver and intestinal loops, gastrointestinal cancers are among the most promising indications of FAP-targeted imaging. Herein, we present a comprehensive review of FAP-targeted imaging in gastrointestinal cancers in order to clarify the current and potential future role of this class of molecules in gastrointestinal oncology.

This review illustrates the imaging features of rhabdomyolysis across multiple modalities and in a variety of clinical scenarios. Rhabdomyolysis is the rapid breakdown of striated muscle following severe or prolonged insult resulting in the release of myocyte constituents into circulation. In turn, patients develop characteristically elevated serum creatine kinase, positive urine myoglobin, and other serum and urine laboratory derangements. While there is a spectrum of clinical symptoms, the classic presentation has been described as muscular pain, weakness, and dark urine. This triad, however, is only seen in about 10% of patients. Thus, when there is a high clinical suspicion, imaging can be valuable in evaluating the extent of muscular involvement, subsequent complications such as myonecrosis and muscular atrophy, and other etiologies or concurrent injuries causing musculoskeletal swelling and pain, especially in the setting of trauma. Sequela of rhabdomyolysis can be limb or life-threatening including compartment syndrome, renal failure, and disseminated intravascular coagulation. MRI, CT, ultrasound, and 18-FDG PET/CT are useful modalities in the evaluation of rhabdomyolysis.

BACKGROUND: Lymph node (LN) involvement is a crucial determinant of prognosis for patients with bladder cancer, and an accurate staging is of utmost importance to better identify timely and appropriate therapeutic strategies. To improve the accuracy of LN detection, as an alternative to traditional methods such as CT or MRI, 18F-FDG PET/CT has been increasingly used. 18F-FDG PET/CT is also used in post-treatment restaging after neoadjuvant chemotherapy. The aim of this narrative literature review is to provide an overview of the current evidence on the use of 18F-FDG PET/CT in the diagnosis, staging, and restaging of bladder cancer, with a particular focus on its sensitivity and specificity for the detection of LN metastasis. We aim to provide clinicians with a better understanding of 18F-FDG PET/CT\'s potential benefits and limitations in clinical practice.
METHODS: We designed a narrative review starting from a wide search in the PubMed/MEDLINE and Embase databases, selecting full-text English articles that have examined the sensibility and specificity of PET/CT for nodal staging or restaging after neoadjuvant therapy in patients with bladder cancer. The extracted data were analyzed and synthesized using a narrative synthesis approach. The results are presented in a tabular format, with a summary of the main findings of each study.
RESULTS: Twenty-three studies met the inclusion criteria: fourteen studies evaluated 18F-FDG PET/CT for nodal staging, six studies examined its accuracy for restaging after neoadjuvant therapy, and three studies evaluated both applications. To date, the use of F-18 FDG PET/TC for detection of LN metastasis in bladder cancer is controversial and uncertain: some studies showed low accuracy rates, but over the years other studies have reported evidence of high sensitivity and specificity.
CONCLUSIONS: 18F-FDG PET/CT provides important incremental staging and restaging information that can potentially influence clinical management in MIBC patients. Standardization and development of a scoring system are necessary for its wider adoption. Well-designed randomized controlled trials in larger populations are necessary to provide consistent recommendations and consolidate the role of 18F-FDG PET/CT in the management of bladder cancer patients.

UNASSIGNED: Irinotecan-loaded drug-eluting beads transarterial chemoembolization (DEBIRI-TACE) is a safe and effective therapeutic option for unresectable colorectal liver metastases (CRLM). The evaluation of treatment response after DEBIRI-TACE is very important for assessing the patient\'s condition. At present, the Response Evaluation Criteria in Solid Tumors (RECIST) with the tumor size obtained by CT and/or MRI and PET Response Criteria in Solid Tumors (PERCIST) based on fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) are used for evaluating the response to therapy of solid tumors; however, their value in the assessment of treatment response after DEBIRI-TACE remains unclear.
UNASSIGNED: A 52-year-old male with unresectable simultaneous CRLM was treated in the Affiliated Hospital of Yanbian University with DEBIRI-TACE combined with systemic chemotherapy and targeted therapy. Carcinoembryonic antigen levels decreased by 82.50% after 27 days of treatment. At 6 weeks post-surgery, FDG-PET/CT showed that the maximum standardized uptake value (SUVmax) of intrahepatic lesions was reduced to 62.14%. Abdominal MRI revealed that the sum of target lesion diameters was less than 30% that at baseline. PERCIST indicated partial metabolic response, whereas RECIST suggested stable disease.
UNASSIGNED: FDG PET/CT-based PERCIST may be accurate in determining treatment response and evaluating patient prognosis after DEBIRI-TACE in unresectable CRLM.

BACKGROUND. FDG PET/CT has limited diagnostic performance in the detection of peritoneal metastasis (PM). Gallium-68-labeled fibroblast activation protein inhibitor (FAPI) targets tumor stroma, leading to high accumulation across cancer types. OBJECTIVE. The purpose of this study was to conduct a meta-analysis to compare the diagnostic performances of 68Ga-FAPI PET/CT and FDG PET/CT in detecting PM on the basis of studies providing head-to-head comparisons between the two tests. EVIDENCE ACQUISITION. PubMed, Embase, and Cochrane Library databases were searched through July 2022 to identify studies reporting head-to-head comparison of 68Ga-FAPI PET/CT and FDG PET/CT for detection of PM. The reference standard was classified as histopathology for all patients or as a combination of histopathologic, clinical, imaging, laboratory, and follow-up information (multidisciplinary reference standard). A random-effects statistical model was applied to conduct a meta-analysis of the diagnostic performances of the tests in patient-based and lesion-based analyses. The QUADAS-2 and QUADAS Comparative tools were used to assess study quality. EVIDENCE SYNTHESIS. Eleven studies were included. Patient-based analysis was reported in nine studies including 340 patients, and lesion-based analysis was reported in four studies including 222 lesions. The pooled sensitivity of 68Ga-FAPI PET/CT was significantly higher than that of FDG PET/CT in patient-based analysis (98.2% [95% CI, 96.1-100.0%] vs 55.9% [95% CI, 33.9-77.9%]) and lesion-based analysis (99.9% [95% CI, 99.5-100.0%] vs 27.3% [95% CI, 11.2-43.4%]). Eight studies were rated at high risk of bias in the reference standard domain because the multidisciplinary reference standard was not sufficiently explained and may have included one of the two index tests, which would have artificially increased sensitivity. In three studies specificity was reported as 100.0% for both tests; these studies were considered at uncertain risk of bias in the patient selection domain because patients with benign peritoneal conditions may have been excluded, resulting in underestimation of potential false-positive results. CONCLUSION. The current evidence suggests excellent sensitivity of 68Ga-FAPI PET/CT for the detection of PM in comparison with poorer sensitivity of FDG PET/CT. However, most included studies had high risk of bias. Further studies are needed to more convincingly characterize true- and false-positive results. CLINICAL IMPACT. The sensitivity of 68Ga-FAPI PET/CT may be substantially greater than that of FDG PET/CT for the evaluation of PM, facilitating surgical planning and candidate selection.

The limited performance of echocardiography in specific infectious processes involving the heart led to the search for additional diagnostic tools. Fluorodeoxyglucose positron emission tomography computed tomography (FDG PET/CT) has been proposed for its diagnostic abilities in several infectious diseases including cardiac infections. A literature review of studies evaluating FDG PET/CT in native valve infective endocarditis (IE), prosthetic valve IE, cardiac implantable electrical device (CIED) infection, and left ventricular assist device (LVAD) infection is presented, focusing on studies published in recent years. Overall, in prosthetic valve endocarditis (PVE), FDG PET/CT demonstrate high sensitivity (73-93%) and specificity (80-95%), while in native valve endocarditis (NVE) the sensitivity is very low (22-68%), with high specificity (97-100%) similar to PVE. For CIED, LVAD infection, and transcatheter aortic valve implantation associated endocarditis, data come from small studies and show good diagnostic performance of FDG PET/CT. International guidelines are increasingly recommending FDG PET/CT for the diagnosis of specific conditions of cardiac infections. Beyond the diagnostic performance ability, few studies have evaluated the added benefit of FDG PET/CT in terms of clinical outcomes of patients with suspected cardiac infection. This should be the focus in future studies.

BACKGROUND: Talaromyces marneffei infection is an important opportunistic infection associated with acquired immune deficiency syndrome (AIDS). However, it is unusual in patients with non-AIDS and other non-immunosuppressed conditions. We report a case of delayed diagnosis of disseminated T. marneffei infection in non-AIDS, non-immunosuppressive and non-endemic conditions.
METHODS: We describe a previously healthy 24-year-old man who complained of a 3-month history of intermittent diarrhea and a recent week of uncontrollable high fever. The HIV antibody test was negative. Enhanced abdominal computed tomography (CT) and integrated 18F-2-deoxy-2-fluoro-D-glucose position emission tomography/computed tomography (FDG PET/CT) both suspected malignant lymphoma. However, a large number of yeast-like cells were found in macrophages in cervical lymph node samples by hematoxylin and eosin stain and silver hexamine stain. Subsequent blood culture suggested T. marneffei infection. Metagenomic Next Generation Sequencing (mNGS) results suggested T. marneffei as the dominant pathogen. Unfortunately, the patient continued to develop acute liver failure and died due to adverse events associated with amphotericin B.
CONCLUSIONS: Early diagnosis in HIV-negative patients who are otherwise not immunosuppressed and endemic poses a serious challenge. T. marneffei infection is an FDG-avid nonmalignant condition that may lead to false-positive FDG PET/CT scans. Nevertheless, integrated FDG PET/CT is necessary in patients with fever of unknown origin in the early period to perform earlier biopsy for histopathology and culture in highly avid sites and to avoid delays in diagnosis and treatment.

A 35-year-old man presented with significant weight loss of 30 kg over the previous 6 months, with newly diagnosed diabetes. Routine laboratory tests were normal, except for markedly elevated blood glucose. Computed tomography (CT) of the abdomen revealed a large severely enhanced mass replacing most of the pancreas and liver metastatic nodules and multiple paraaortic lymph node metastases, 18F-fluorodeoxygluocse positron emission tomography/computed tomography (18F-FDG PET/CT) was performed and revealed mild FDG uptake in the pancreatic mass, as well as mild uptake in the liver and lymph node metastases. A biopsy of the liver metastasis was consistent glucagonoma that was confirmed with markedly elevated serum glucagon level. Subsequently, 68Ga-DOTATATE PET/CT was performed for better tumor characterization and for assessment of the tumors\' response to therapy, 68Ga-DOTATATE scan revealed intense uptake in the pancreatic mass, liver metastases, and paraaortic lymph node metastases. The patient responded well to peptide receptor radionuclide therapy. This case highlights the role of both 68Ga-DOTATATE and 18FDG-PET/CT in the diagnosis and management of a glucagonoma. 68Ga-DOTATATE is the tracer of choice for well-differentiated glucagonoma and offers very high diagnostic accuracy as compared with that of cross-sectional and other functional imaging and enables correct patient selection for peptide receptor radionuclide therapy.

Lung cancer is a fairly common malignancy. An early diagnosis and a reliable staging and re-staging with the aim to detect both local and distant relapse are of utmost importance in planning the therapeutic management. The imaging diagnostic work-up of patients with lung cancer usually includes conventional imaging (chest X-ray, contrast-enhanced CT, bone scan) and more recently 18F-FDG PET/CT. Great advances in the management of lung cancer are based on the information provided by 18F-FDG PET/CT, as it supplies both metabolic and anatomic information (better localisation). There is vast evidence in the literature demonstrating its utility in (a) characterising benign versus malignant solitary nodules, (b) staging and re-staging lung cancer, (c) guiding the type of therapy, (d) monitoring treatment response and (e) predicting outcome. In particular, given its specificity in differentiating 18F-FDG-avid relapse from post-surgical changes or post-radiation fibrosis (which do not take up 18F-FDG), PET/CT can detect recurrent disease after initial treatment and (being a whole-body technique) has demonstrated high accuracy in the detection of distant metastases or secondary tumours. In conclusion, 18F-FDG PET/CT can be considered a highly accurate and reliable method for staging and re-staging lung cancer, and is highly effective in guiding personalised therapies.