Increased 18 F-FAPI-04 Uptake in Vertebral Hemangioma.

ABSTRACT: A 54-year-old man with a history of colectomy for colorectal cancer and subsequent liver metastasectomy underwent 18 F-FDG PET/CT and 18 F-FAPI-04 PET/CT scans to evaluate possible hepatic metastasis revealed by contrast-enhanced MRI. Both studies showed similarly increased uptake in liver metastases, and 18 F-FDG detected a metastatic lung nodule. Furthermore, the images showed an incidental finding of increased uptake of 18 F-FAPI-04 in the L3 vertebral, which was not 18 F-FDG-avid. A review of the patient's previous CT and MRI scans suggests vertebral hemangioma.

Development and validation of an MRI-based nomogram for the preoperative prediction of tumor mutational burden in lower-grade gliomas.

Background: High tumor mutational burden (TMB) is an emerging biomarker of sensitivity to immune checkpoint inhibitors. In this study, we aimed to determine the value of magnetic resonance (MR)-based preoperative nomogram in predicting TMB status in lower-grade glioma (LGG) patients. Methods: Overall survival (OS) data were derived from The Cancer Genome Atlas (TCGA) and then analyzed by using the Kaplan-Meier method and time-dependent receiver operating characteristic (tdROC) analysis. The magnetic resonance imaging (MRI) data of 168 subjects obtained from The Cancer Imaging Archive (TCIA) were retrospectively analyzed. The correlation was explored by univariate and multivariate regression analyses. Finally, we performed tenfold cross validation. TMB values were retrieved from the supplementary information of a previously published article. Results: The high TMB subtype was associated with the shortest median OS (high vs. low: 50.9 vs. 95.6 months, P<0.05). The tdROC for the high-TMB tumors was 74% (95% CI: 61-86%) for survival at 12 months, and 71% (95% CI: 60-82%) for survival at 24 months. Multivariate logistic regression analysis confirmed that three risk factors [extranodular growth: odds ratio (OR): 8.367, 95% CI: 3.153-22.199, P<0.01; length-width ratio ≥ median: OR: 1.947, 95% CI: 1.025-3.697, P<0.05; frontal lobe: OR: 0.455, 95% CI: 0.229-0.903, P<0.05] were significant independent predictors of high-TMB tumors. The nomogram showed good calibration and discrimination. This model had an area under the curve (AUC) of 0.736 (95% CI: 0.655-0.817). Decision curve analysis (DCA) demonstrated that the nomogram was clinically useful. The average accuracy of the tenfold cross validation was 71.6% for high-TMB tumors. Conclusions: Our results indicated that a distinct OS disadvantage was associated with the high TMB group. In addition, extranodular growth, nonfrontal lobe tumors and length-width ratio ≥ median can be conveniently used to facilitate the prediction of high-TMB tumors.

Langerhans cell histiocytosis presenting as an isolated brain tumour: A case report.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare proliferative histiocyte disorder. It can affect any organ or system, especially the bone, skin, lung, and central nervous system (CNS). In the CNS, the hypothalamic-pituitary is predominantly affected, whereas the brain parenchyma is rarely affected. LCH occurring in the brain parenchyma can be easily confused with glioblastoma or brain metastases. Thus, multimodal imaging is useful for the differential diagnosis of these intracerebral lesions and detection of lesions in the other organs. CASE SUMMARY: A 47-year-old man presented with a headache for one week and sudden syncope. Brain computed tomography (CT) and magnetic resonance imaging showed an irregularly shaped nodule with heterogeneous enhancement. On 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/CT, a nodule with 18F-FDG uptake and multiple cysts in the upper lobes of both lungs were noted, which was also confirmed by high-resolution CT. Thus, the patient underwent surgical resection of the brain lesion for further examination. Postoperative pathology confirmed LCH. The patient received chemotherapy after surgery. No recurrence was observed in the brain at the 12-mo follow-up. CONCLUSION: Multimodal imaging is useful for evaluating the systemic condition of LCH, developing treatment plans, and designing post-treatment strategies.

Combined PET/CT with thoracic contrast-enhanced CT in assessment of primary cardiac tumors in adult patients.

BACKGROUND: 18F-FDG PET/CT is a key molecular imaging modality to noninvasively assess and differentiate benign and malignant cardiac tumors. However, few benign cardiac tumors can be characterized by increased 18F-FDG uptake, which makes differential diagnosis difficult. This study sought to retrospectively evaluate whether combined 18F-FDG PET/CT with thoracic contrast-enhanced CT (CECT) helps in assessing primary cardiac tumors in adult patients, compared with CECT or PET/CT alone. METHODS: Forty-six consecutive patients who were diagnosed as primary cardiac tumors were enrolled. All patients underwent 18F-FDG PET/CT followed by thoracic CECT before biopsy or surgery. Visual qualitative interpretation and quantitative analysis were performed, and diagnostic performance was evaluated. RESULTS: More than half (16/29) of benign tumors exhibited with mild 18F-FDG uptake. There were significant differences in 18F-FDG uptake and the degree of absolute enhancement between benign and malignant tumors (P < 0.001). The combination of two modalities improved the specificity from 79 to 93%, the positive predictive value from 73 to 89%, and the accuracy of diagnosis from 85 to 93%. There were significant differences between PET/CT alone or thoracic CECT alone and combined modalities (P = 0.034 and P = 0.026, respectively). The combination with the optimal SUVmax cutoff value generated 94% sensitivity, 100% specificity, 97% negative predictive values, 100% positive predictive values, and 98% accuracy rates. CONCLUSIONS: Combining 18F-FDG PET/C with thoracic CECT significantly improved specificity and accuracy compared to CECT or PET/CT alone in detecting tumors. This combination of diagnostic imaging is effective in differentiating malignant from benign masses.

Adult Pancreatoblastoma With Liver Metastasis Diagnosed by 18F-FDG PET/CT and 2 Years' Postoperative Follow-up.

Pancreatoblastoma is an extremely rare malignant tumor of the pancreas. Most patients are infants and children; however, a few cases have been reported in adults. Herein, we present the case of a 49-year-old man with pancreatoblastoma and liver metastasis who underwent preoperative multimodal imaging, in which F-FDG PET/CT showed a markedly increased F-FDG uptake in the metastatic lesion and a slightly increased uptake in the primary lesion. Subsequently, the patient underwent complete resection of the primary and metastatic lesions. No recurrences or metastases were found in 2 years of follow-up.

FDG-PET/CT of invasive thymoma extending into the superior vena cava and right atrium.

We present FDG PET/CT findings of a rare case of invasive thymoma with intraluminal growth into the superior vena cava (SVC) and right atrium (RA).

18F-FDG PET/CT and contrast-enhanced CT findings of pulmonary cryptococcosis.

PURPOSE: Pulmonary cryptococcosis is an uncommon cause of pulmonary nodules in non-AIDS patients. This study reports the 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG PET/CT) and contrast-enhanced CT (CE-CT) findings of 42 patients with pulmonary cryptococcosis. MATERIALS AND METHODS: A retrospective review of the 18F-FDG PET/CT and CE-CT findings of 42 patients with histologically proven pulmonary cryptococcosis was conducted. All patients underwent PET/CT and CE-CT in the same session. The CT diagnosis was based on the location, morphological features, and enhancement of lesions. The PET/CT findings were recorded, and clinical data and surgical and histopathological findings were collected. RESULTS: The results of the PET scans revealed that 37 (88%) of 42 patients showed higher FDG uptake, and 5 (12%) patients demonstrated lower FDG uptake than the mediastinal blood pool. The maximum standardized uptake value (SUV) of pulmonary cryptococcosis ranged from 1.4 to 13.0 (average: 5.7±3.3, median 4.9). A single nodular pattern was the most prevalent pattern observed and was found in 29 (69%) patients. This pattern was followed by scattered nodular (n=4, 10%), clustered nodular (n=3, 7%), mass-like (n=3, 7%), and bronchopneumonic (n=3, 7%) patterns. The most frequent pattern of immunocompetent patients was the single nodular pattern (29 of 33, 88%). Immunocompromised patients most frequently pattern exhibited mass-like (3 of 9, 33%) and bronchopneumonic (3 of 9, 33%) patterns. CONCLUSION: Pulmonary cryptococcosis most commonly appears as single nodules in immunocompetent patients. Mass-like and bronchopneumonic patterns were common in immunocompromised patients. In 88% of patients, lung lesions showed high FDG uptake, thus mimicking a possible malignant condition.

FDG PET/CT of Intercostal Schwannoma.

Intercostal schwannoma is rare. We report FDG PET/CT findings of intercostal schwannoma in a 66-year-old woman. The tumor contains both solid and cystic components with intense FDG activity in the solid component. Postsurgical pathology diagnosis revealed schwannoma.