The Complementary Role of 68Ga-FAPI-04 PET/CT in a Case of Neuroblastoma.

ABSTRACT: As a common and highly aggressive malignancy of childhood, more than half of neuroblastomas are metastatic at the time of presentation. Herein, we reported 68Ga-FAPI-04 and 18F-FDG PET/CT findings in a 13-year-old girl with undifferentiated neuroblastoma. FAPI PET/CT showed intense uptake in the bone and bone marrow metastases. The primary lesions presented with low FAPI uptake but moderate FDG uptake. Above findings suggested the potential of FAPI PET/CT in the imaging evaluation of neuroblastoma.

Fluorine-18 fluorodeoxyglucose uptake change in liver, mediastinal blood pool, and lymphoid cell-rich organs during programmed cell death-1 immunotherapy in lymphoma.

PURPOSE: The aim of this study was to evaluate metabolism change in reference organs (liver and mediastinum) and lymphoid cell-rich organs (spleen and bone marrow) during programmed cell death-1 immunotherapy in relapsed or refractory lymphoma patients. METHODS: A total of 66 patients with baseline and serial monitoring fluorodeoxyglucose (FDG) PET/computed tomography scans were retrospectively enrolled. Mean standardized uptake value (SUV) and maximum SUV of evaluated organs were obtained by two reviewers, and their association with tumor burden and clinical response were evaluated. Immune-related adverse events detected by FDG PET/computed tomography were also recorded. RESULTS: The SUV values of reference organs and lymphoid cell-rich organs did not change significantly during the immunotherapy process. The intersubject variability of these values ranged from 13.0 to 28.5%. Meanwhile, metabolism of reference organs was affected by neither the tumor burden nor clinical response. SUV change of lymphoid cell-rich organs was associated with clinical response to immunotherapy. Responders showed decreased metabolism, while nonresponders showed a reverse trend (spleen SUV max : -0.30 ±â€…0.47 vs. 0.18 ±â€…0.39, P  = 0.001, spleen SUV mean : -0.24 ±â€…0.39 vs. 0.14 ±â€…0.31, P  = 0.001; and bone marrow SUV max : -0.14 ±â€…0.37 vs. 0.07 ±â€…0.46, P  = 0.042, respectively). The influence of immune-related adverse events on the SUV change in evaluated organs was not significant. CONCLUSION: During programmed cell death-1 immunotherapy, metabolism change of reference organs is influenced neither by tumor burden nor by clinical response, while FDG uptake change of lymphoid cell-rich organs is significantly associated with clinical response.

Gastric Fundus Splenosis Mimicking Malignancy on FDG PET/CT.

ABSTRACT: A 17-year-old man presented with dull pain in the left upper abdomen for 1 month. Initial CT and gastroscopy revealed a mass in the gastric fundas, protruding into the lumen. Based on findings of a fine-needle biopsy, an inflammatory myofibroblastic tumor was suspected. Subsequent PET/CT showed increased FDG uptake in the gastric fundas as well as hepatogastric ligament, para-aortic region. Eventually, he underwent surgical resection, and histopathologic findings confirmed the diagnosis of splenosis.

Eosinophilic Cystitis Mimicking Malignancy on FDG PET/CT.

ABSTRACT: A 64-year-old man had progressive dysuria and nocturia for 1 month. Initial MRI and CT revealed localized thickening of the bladder wall with significant enhancement. Meanwhile, the lesion showed intense FDG accumulation on the delayed PET/CT. Taken together, a malignancy was suspected. However, the pathologic findings confirmed the diagnosis of eosinophilic cystitis.

Pretargeted radiotherapy and synergistic treatment of metastatic, castration-resistant prostate cancer using cross-linked, PSMA-targeted lipoic acid nanoparticles.

Metastatic castration-resistant prostate cancer (CRPC) is a currently incurable disease associated with high mortality. Novel therapeutic approaches for CRPC are urgently needed to improve prognosis. In this study, we developed cross-linked, PSMA-targeted lipoic acid nanoparticles (cPLANPs), which can interact with transmembrane glycoprotein to accumulate inside prostate cancer cells, where they upregulate caspase-3, downregulate anti-apoptotic B-cell lymphoma-2 (BCL-2), and thereby induce apoptosis. The trans-cyclooctene (TCO) decoration on cPLANPs acts as a bioorthogonal handle allowing pretargeted single-photon emission computed tomography and radiotherapy, which revealed significantly enhanced tumor accumulation and minimal off-target toxicity in our experiments. The developed strategy showed a strong synergistic anti-cancer effect in vivo, with a tumor inhibition rate of up to 95.6% after 14 days of treatment. Our results suggest the potential of combining bioorthogonal pretargeted radiotherapy with suitable PSMA-targeted nanoparticles for the treatment of metastatic CRPC.

FDG PET/CT may replace bone marrow biopsy for the evaluation of bone marrow involvement in selected mature T- and natural killer-cell lymphomas: A meta-analysis.

PURPOSE: To systematically determine the role of FDG PET/CT for the diagnosis of bone marrow involvement in mature T- and natural killer (NK)-cell lymphomas. METHODS: The PubMed, Embase and Cochrane Library databases were searched to identify eligible studies. Data extraction and quality assessment were independently conducted. Then, pooled diagnostic performance with the 95 % confidence interval (CI) was calculated and further analyzed based on different interpretation criteria, tumor type and stage. RESULTS: Fifteen studies were eventually included for quantitative analysis. Overall, the methodological quality of included studies was acceptable. For detecting bone marrow involvement, FDG PET/CT achieved a poor sensitivity of 0.62 (95 % CI, 0.48-0.71) and a reasonable specificity of 0.92 (95 % CI, 0.87-0.96). Similar performance was observed for the specific type of extranodal NK/T-cell lymphoma (ENKTCL). In early-stage patients revealed by PET/CT, extremely small proportion (2/777) showed positive bone marrow biopsy, especially for the specific type of ENKTCL, whereas in advanced-stage patients, the specificity of FDG PET/CT dropped to 0.77 (95 % CI, 0.72-0.82). Regarding the interpretation, both diffuse and focal increased uptake patterns as positivity may result in increased sensitivity but decreased specificity compared with focal pattern alone as positivity. CONCLUSIONS: FDG PET/CT demonstrated excellent negative predictive value for detecting marrow involvement in early-stage patients with mature T- and NK-cell lymphomas, especially the ENKTCL. Conversely, FDG PET/CT showed poor performance for the diagnosis of bone marrow involvement in advanced-stage patients.

Incidental Detection of Urinary Leakage on FDG PET/CT Imaging.

ABSTRACT: A 57-year-old woman previously diagnosed as cervical cancer underwent an 18 F-FDG PET/CT scan for restaging. A pelvic encapsulated effusion with intense FDG accumulation was incidentally revealed. The tracer activity was similar to that of urine, indicating presence of urinary leakage. Subsequent CT urography confirmed the complete avulsion of the right distal ureter.

Enterovesical Fistula in a Lymphoma Patient Revealed by FDG PET/CT With an Oral Contrast Agents.

ABSTRACT: A 60-year-old man with colonic diffuse large B-cell lymphoma was referred for FDG PET/CT for initial staging. He was suspected of enterovesical fistula. After oral administration, large amounts of contrast agents accumulated in the bowel lumen and leaked into the bladder through a well-marked fistulous tract. Corresponding to the fistula, a linear pattern of FDG uptake extended from the bladder into the colonic lumen, and the measured SUV max inside the lesion was as high as that of the urinary bladder. Cystography confirmed the presence of the enterovesical fistula.

Life-Threatening Involvement of Bilateral Pulmonary Arteries in Behçet Disease on FDG PET.

ABSTRACT: A 29-year-old man with Behçet disease exhibiting lower-limb swelling and dyspnea underwent 18 F-FDG PET/CT. The imaging revealed bilateral pulmonary artery involvement, and pulmonary artery aneurysms and mural thrombus were confirmed by CT pulmonary angiography. This case underscores the utility of 18 F-FDG PET in identifying life-threatening vasculitis complications in Behçet disease.

Effects of somatostatin analogs on uptake of radiolabeled somatostatin analogs on imaging: a systematic review and meta-analysis.

Background: The imaging of somatostatin receptors (SSTRs) plays a significant role in imaging neuroendocrine tumors (NETs). However, there has been no clear definition on whether it is necessary to withdraw somatostatin analogs (SSAs) before SSTRs imaging. We aimed to assess whether nonradioactive SSAs affect the uptake of radiolabeled SSAs on imaging for NETs patients. Methods: The databases of PubMed, Embase, and Web of Science (WoS) were searched until March 12, 2022 to identify eligible studies. Maximum standardized uptake values (SUVmax) in tumor and normal tissues were extracted, pooled, and compared before and after SSAs treatment. The change of tumor-to-background/liver ratio was also described. The quality of each study was assessed using the revised Quality Assessment of Diagnostic Accuracy Studies-2 tool. Results: A total of 9 articles involving 285 patients were included and 5 studies using Gallium-68-labeled [1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid]-D-Phe1-Tyr3-Thr8-octreotide (68Ga-DOTATATE) were used for pooled evaluation. We found a significantly decreased SUVmax in the liver (9.56±2.47 vs. 7.62±2.12, P=0.001) and spleen (25.74±7.14 vs. 20.39±6.07, P=0.006) after SSAs treatment whereas no significant differences were observed in the uptake of thyroid, adrenal, and pituitary gland. For either primary tumor sites or metastases, the SUVmax did not change significantly before and after SSAs treatment. The tumor-to-liver/background ratio increased following SSAs therapy. High heterogeneity was observed across the studies, mainly due to inherent diversity of study design, sample size, and scanning technique. Conclusions: Based on current evidence, long-acting SSAs therapy before imaging has no effect on the uptake of radiolabeled SSAs at tumor primary sites and metastatic lesions, but results in a significant reduction of uptake in the liver and spleen. These findings may implicate the unnecessary discontinuation of SSAs before radiolabeled SSAs imaging.

Bilateral Pulmonary Enteric Adenocarcinoma on FDG PET/CT.

ABSTRACT: Pulmonary enteric adenocarcinoma(PEAC) is a rare variant of pulmonary adenocarcinoma. We herein report FDG PET/CT findings of PEAC in a 76-year-old woman. The images showed widespread opacities in both lungs with intense FDG uptake. The pathology revealed pulmonary enteric adenocarcinoma.

Intense Axillary Accumulation of 99m Tc-MDP Due to Perspiration.

ABSTRACT: Prostate cancer was newly diagnosed in a 73-year-old man. He underwent bone scintigraphy to assess any skeletal involvement. No abnormal uptake was observed in the skeletal system, whereas intense radioactivity was seen in the bilateral axillary regions. Physical examination found large amounts of sweat. Repeat images revealed no axillary activity after washing. This case illustrated axillary accumulation of 99m Tc-MDP due to perspiration.

Increased 68Ga-DOTATATE Uptake in Supraclavicular Brown Adipose Tissue.

ABSTRACT: Characterization of brown adipose tissue (BAT) 18F-FDG uptake has been well reported; however, 68Ga-DOTA-conjugated somatostatin receptor targeting peptides uptake in BAT is rarely documented. Herein, we report an interesting case of increased 68Ga-DOTATATE uptake in supraclavicular BAT in a young boy with paroxysmal hypertension. The low body mass index and increased perfusion of BAT in response to cold may be significant influencing factors.

Bioorthogonal Cleavage of Tetrazine-Caged Ethers and Esters Triggered by trans-Cyclooctene.

In this study, we report the bioorthogonal cleavage of physiologically stable methylene tetrazines bearing an ether or ester linkage in the presence of trans-cyclooctene. Based on this approach, molecules with phenol or carboxylic acid moieties were efficiently released in a controlled manner, which can be effectively applied in living cells. We expect this bioorthogonal cleavage approach can be applied to several biomedical applications, including the development of antibody-drug conjugates, pretargeted prodrug release, and protein activation.

Nasal-Type NK/T-Cell Lymphoma Involvement of the Vocal Cord on FDG PET/CT.

ABSTRACT: Nasal-type extranodal natural killer/T-cell lymphoma (ENKTL) rarely involves the vocal cord. Herein, we present a case of an ENKTL patient with vocal cord involvement revealed by FDG PET/CT. Nasopharyngoscopy showed a neoplasm in the larynx, which was eventually confirmed as ENKTL by immunohistochemical results. PET/CT was subsequently performed for staging, and intense FDG uptake in the left side of vocal cord suggested ENKTL involvement.

Solitary Fibrous Tumor of the Bone Detected by FDG PET/CT.

ABSTRACT: Solitary fibrous tumor as a rare mesenchymal tumor can occur in a wide variety of body sites, including serosal membranes, liver, lung, and deep soft tissues; however, primary tumor arising in bone is rarely documented. Herein, we reported the MRI, bone scan, and FDG PET/CT findings of a primary spinal solitary fibrous tumor in a 39-year-old woman.

131I-Labeled Silk Fibroin Microspheres for Radioembolic Therapy of Rat Hepatocellular Carcinoma.

Transarterial radioembolization (TARE) is a promising technology in hepatocellular carcinoma (HCC) therapy, which utilizes radionuclide-labeled microspheres to achieve arterial embolization and internal irradiation. However, the therapeutic effect of liver cancer can be affected by low radionuclide labeling rate and stability, as well as poor biocompatibility, and non-biodegradability of microspheres. Here, 131I-labeled silk fibroin microspheres (131I-SFMs) were developed as radioembolization material for effective TARE therapy against HCC. Silk fibroin rich in 10.03% of tyrosine was extracted from silkworm cocoons and then emulsified and genipin-crosslinked to prepare SFMs. SFMs show a good settlement rate, biodegradability, hemocompatibility, and low cytotoxicity. Afterward, 131I-SFMs were obtained by radiolabeling 131I onto the SFMs through the chloramine-T method. 131I-SFMs possess a high 131I labeling rate of over 84% and good radioactive stability and are thus conducive to internal radiotherapy. Significantly, 131I-SFMs with diameters around 11 µm were successfully radioembolized at the hepatic artery. 131I-SFMs were diffused in the liver, indicating the favorable biodistribution and biosafety in vivo. Based on the combination of embolization and local radiotherapy, the administration of 131I-SFMs shows a favorable inhibitive effect against the progression of HCC. Overall, the newly developed 131I-SFMs as radioembolization microspheres provide a promising application for effective TARE therapy against liver cancer.