Diagnostic performance of FDG PET/MRI for cervical lymph node metastasis in patients with clinically N0 head and neck cancer.

OBJECTIVE: Treatment management in cases of head and neck squamous cell cancer (HNSCC) that are clinically negative for lymph node metastases (cN0) is still an important topic of discussion. There is increasing interest in sensitive imaging modalities that can detect the risk of occult metastases at levels below 20%. This study aimed to examine the efficacy of integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) in determining neck nodal metastasis status in cN0 patients with HNSCC. PATIENTS AND METHODS: In this retrospective study, 44 patients who underwent neck dissection with the diagnosis of HNSCC between January 2018 and August 2020 were analyzed. Clinical examinations, including ultrasonography, were performed to identify cervical metastases in HNSCC patients with preoperative cN0. A nuclear medicine specialist visually evaluated the MRI, PET, and PET/MRI results. RESULTS: Histopathologically, 86.4% of patients were classified as N0. According to the histopathological results, MRI showed 50% sensitivity, 89.5% specificity, 91.8% negative predictive value (NPV), 42.8% positive predictive value (PPV) and 84% accuracy, while PET showed 83.3% sensitivity, 68.4% specificity, 96.2% NPV, 29.4% PPV and 70.4% accuracy. PET/MRI was more successful in distinguishing pathological N0 and N+ patients (83.3% sensitivity, 92.1% specificity, 97.2% NPV, 62.5% PPV and 90.9% accuracy). CONCLUSIONS: PET/MRI is more sensitive and has a higher NPV compared to MRI alone, while its sensitivity was found to be comparable to that of PET. In addition, with its ability to detect pathological N0 patients, PET/MRI may significantly decrease the number of unnecessary neck dissections.

Respiratory-gated 18F Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Imaging in Evaluation of Primary Gastric Lesions and Gastric Lymph Nodes in Patients with Gastric Cancer.

AIMS: To evaluate the added value of respiratory-gated positron emission tomography (PET) in 18F fluorodeoxyglucose (FDG) PET/magnetic resonance imaging (MRI) in the visual and semi-quantitative assessment of primary gastric lesions and gastric lymph nodes for patients with gastric cancer. MATERIALS AND METHODS: In total, 102 upper abdominal respiratory-gated and whole-body 18F FDG PET/MRI of 88 patients with gastric cancer were evaluated visually and semi-quantitatively. For 41 patients who underwent surgery, histopathological and PET findings were compared. Three PET images were obtained from upper abdominal PET data: non-Q static (non-QS) PET from all counts, respiratory-gated Q static (QS) PET from counts in the end-expiration phase of breathing, shortened 4 min (S4min) PET that was reconstructed to obtain similar counts to QS PET. The semi-quantitative parameters (standardised uptake values, metabolic tumour volume, total lesion glycolysis) of primary lesions for each PET image, the sizes of primary lesions and the patient's body mass index were recorded. According to lymph node stations, the presence and numbers of positive lymph nodes and visual scores of lymph nodes for each PET image were recorded. RESULTS: The patients with smaller gastric lesions (≤30 mm) or higher body mass index (>30) had significantly higher standardised uptake value percentage changes in QS PET compared with non-QS PET (all P < 0.05). The third (lesser curvature), fourth (greater curvature) and sixth (infra-pyloric) lymph node stations had significantly higher visual scores in the QS PET than in the others. The fourth lymph node station had a significantly higher number of FDG-positive lymph node in the QS PET than in the non-QS and the whole-body PET images. In the fourth station, sensitivity, positive predictive value, negative predictive value and accuracy increased in the QS PET compared with the others. CONCLUSION: Respiratory-gated PET/MRI was found to be significantly superior in the evaluation of especially the fourth lymph node station, smaller gastric lesions and in the patients with a higher BMI compared with the non-respiratory-gated PET images.

Texture features of primary tumor on 18F-FDG PET images in non-small cell lung cancer: The relationship between imaging and histopathological parameters. / Características de textura del tumor primario en imágenes de 18F-FDG PET en cáncer de pulmón de células no pequeñas: la relación entre parámetros de imágenes y parámetros histopatológicos.

OBJECTIVES: The aims of this study were to evaluate the relationships between textural features of the primary tumor on FDG PET images and clinical-histopathological parameters which are useful in predicting prognosis in newly diagnosed non-small cell lung cancer (NSCLC) patients. MATERIAL AND METHODS: PET/CT images of ninety (90) patients with NSCLC prior to surgery were analyzed retrospectively. All patients had resectable tumors. From the images we acquired data related to metabolism (SUVmax, metabolic tumor volume [MTV] and total lesion glycolysis [TLG]) and texture features of primary tumors. Histopathological tumor types and subgroups, degree of Ki-67 expression and necrosis rates of the primary tumor, mediastinal lymph node (MLN) status and nodal stages were recorded. RESULTS: Among the 2histologic tumor types (adenocarcinoma and squamous cell carcinoma) significant differences were present regarding metabolic parameters, Ki-67 index with higher values and kurtosis with lower values in the latter group. Textural heterogeneity was found to be higher in poorly differentiated tumors compared to moderately differentiated tumors in patients with adenocarcinoma. While Ki-67 index had significant correlations with metabolic parameters and kurtosis, tumor necrosis rate was only significantly correlated with textural features. By univariate and multivariate analyses of the imaging and histopathological factors examined, only gradient variance was significant predictive factor for the presence of MLN metastasis. CONCLUSIONS: Textural features had significant associations with histologic tumor types, degree of pathological differentiation, tumor proliferation and necrosis rates. Texture analysis has potential to differentiate tumor types and subtypes and to predict MLN metastasis in patients with NSCLC.

E-cadherin expression in endometrial malignancies: comparison between endometrioid and non-endometrioid carcinomas.

This study examined the frequency of E-cadherin expression in endometrial biopsy or hysterectomy specimens from patients diagnosed with endometrial adenocarcinoma and in normal endometrial tissue specimens. E-cadherin expression was detected by immunohistochemistry using monoclonal antibody to E-cadherin. Specimens were classified as positive when >or= 5% of the tumour cells showed staining for E-cadherin, irrespective of the pattern of staining. Twenty-three endometrioid carcinomas and nine non-endometrioid (four papillary serous and five clear cell) carcinomas were studied, along with 10 normal endometrial tissue specimens as controls. E-cadherin expression was significantly less frequent in non-endometrioid carcinomas compared with endometrioid carcinomas and controls. There was no statistically significant difference in the frequency of E-cadherin expression between endometrioid carcinomas and controls. In conclusion, this study demonstrated that uterine non-endometrioid (papillary serous and clear cell) carcinomas were less likely to express E-cadherin compared with endometrioid carcinomas and normal endometrial tissue. This may help to explain the more aggressive behaviour of non-endometrioid carcinomas.