Increased right ventricular glucose metabolism in patients with pulmonary arterial hypertension.

BACKGROUND AND AIMS: We aimed to assess the characteristics of glucose utilization in left and right ventricle (LV, RV) myocardium with F-18 fluorodeoxyglucose (FDG) on positron emission tomography in patients with pulmonary arterial hypertension (PAH), and to evaluate whether predominance of RV glucose metabolism as compared with that in LV relates to clinical, hemodynamic, echocardiographic, and neurohormonal parameters. METHODS: The study group comprised 23 patients with PAH and 16 healthy controls who underwent FDG positron emission tomography. The ratio of RV uptake (u) of FDG to those of LV was used as a marker for the glucose utilization by RV myocardium. Six-minute walking distance, plasma brain natriuretic peptide (BNP), planimetric echo measures of RV and LV areas, pulmonary arterial systolic pressure estimated by Doppler, Tei index, tricuspid annular excursion, and systolic tissue velocity (St) were used to assess the RV function. RESULTS: The patients with PAH had significantly higher FDG SUV ratios as compared with controls. The RV to LV FDGu ratio showed a high correlation with PAPs (r=0.87, P<0.05), BNP (r=0.63, P<0.05), and planimetric echo measures of RV to LV area ratio (r=0.61, P<0.05); a mild correlation with Tei index (r=0.47, P<0.05); and a high and inverse correlation with tricuspid annular excursion (r=-0.80, P<0.05), 6-minute walking distance (r=-0.74, P<0.05), and St (r=-0.68, P<0.05). CONCLUSIONS: Increased RV myocardium FDG accumulation indicates increased RV loading that correlates with prognostic markers in pulmonary hypertension including reduced exercise capacity, elevated BNP, and echo variables of tricuspid annular function. Moreover, identification of increased RV FDG accumulation predicts the presence but not the severity of elevated pulmonary systolic pressure.

Pulmonary BALT lymphoma successfully treated with eight cycles weekly rituximab: report of first case and F-18 FDG PET/CT images.

Extra marginal-zone lymphomas of the lung is a very rare tumor and it originates from bronchial-associated lymphoid tissue. A 68-yr-old woman presented with productive cough and dyspnea. A thorax computed tomography scan showed a 9 × 10 cm in size mass in the left lung and pleural effusion in the lower lobe of left lung. Positron emission tomography/computed tomography (PET/CT) revealed intense uptake foci at the upper and middle sites of left lung and slight uptake foci at the mediastinal lymph nodes which showed malignant involvement. After bronchoscopic biopsy, the diagnosis of pulmonary bronchial-associated lymphoid tissue (BALT) lymphoma was confirmed. At the end of the eight cycles weekly rituximab treatment, complete response was obtained by PET/CT findings. It is concluded that extended rituximab schedule is more effective and it would be beneficial to investigate the use of PET/CT in the diagnosis and evaluating of the treatment response of pulmonary BALT lymphoma.

The role of ¹8F-FDG PET/CT in the assessment of suspected recurrent gastric cancer after initial surgical resection: can the results of FDG PET/CT influence patients' treatment decision making?

PURPOSE: (18)F-fluorodeoxyglucose (FDG) PET/CT has been widely used for staging, re-staging and for monitoring therapy-induced changes and response to therapy in patients with various types of cancer, but its utilization for gastric cancer has been limited. The purpose of this study was to evaluate the clinical role of FDG PET/CT in the detection of gastric cancer recurrence as compared with diagnostic CT and to assess the impact of FDG PET/CT results on patients' treatment planning. METHODS: Thirty-four patients with suspected recurrent gastric cancer, who had previously undergone curative gastrectomy and lymph node dissection, were retrospectively analysed. The diagnostic CT and FDG PET/CT imaging were performed for all patients as clinically indicated. The results of FDG PET/CT were compared with the findings of the diagnostic CT. The changes in the clinical management of patients according to the results of FDG PET/CT were also evaluated. RESULTS: FDG PET/CT was performed in 19 patients (55.9%) due to the suspicion of distant metastasis at diagnostic CT. The remaining 15 patients were suspected to have local recurrence at diagnostic CT (n = 4) or gastroscopy (n = 1) and due to an increase in tumour markers or clinical manifestations (n = 10). The FDG PET/CT result was positive in 23 patients (67.6%) and negative in 11 patients (32.4%). In total, 24 (70.6%) of the 34 patients had documented recurrent disease by histopathology in 7 (29.1%) and by clinical follow-up in 17 (70.9%), while 11 patients had no evidence of recurrent disease. FDG PET/CT correctly confirmed recurrent disease in 23 of the patients with recurrence and it was classified as true-positive in these patients. However, FDG PET/CT was false-negative in one patient but recurrent disease was confirmed by histopathology. The overall sensitivity, specificity, accuracy, positive and negative predictive values of FDG PET/CT were significantly superior to those of diagnostic CT (95.8 vs 62.5%, 100 vs 10%, 97 vs 47%, 100 vs 62.5% and 90.9 vs 10%, respectively, p = 0.012) in the detection of recurrent gastric cancer after initial surgery. The FDG PET/CT results changed the patients' management in 18 (52.9%) cases by leading to the use of previously unplanned treatment procedures in 9 (50%) patients and the avoidance of previously planned therapeutic procedures in 9 (50%) patients. CONCLUSION: FDG PET/CT is a superior post-therapy surveillance modality for the diagnosis of recurrent gastric cancer compared with diagnostic CT imaging after initial surgery. In addition, integrated FDG PET/CT was specifically helpful in optimizing the treatment plan and it might play an important role in treatment stratification in the future.

The role of PET-CT in the differential diagnosis of thymic mass after treatment of patients with lymphoma.

Thymic hyperplasia is a common phenomenon in both children and young adults after chemotherapy and may explain the finding of a mediastinal mass in patients with malignant lymphoma after complete remission. In the present study, we report 5 cases with malignant lymphoma presenting with a mediastinal mass on CT scan after completion of chemotherapy diagnosed as thymic hyperplasia by PET-CT imaging. We retrospectively analyzed 5 patients who presented with anterior mediastinal masses a median of 4 months (range 3-6) after achieving complete remission following successful treatment for malignant lymphoma. Three patients were diagnosed with Hodgkin's lymphoma (HL) and the others with non-Hodgkin's lymphoma (NHL). The median age of the patients was 23 (range of 18-47). PET-CT was performed on these patients to determine the characteristics of a mass which had been detected on CT. PET-CT was performed for all patients, and the thymic masses demonstrated only mild FDG uptake considered to be consistent with thymic hyperplasia. During a median of 24 months of follow-up, all patients were recurrence-free with a median survival of 15 months (range 10-26 months). It is important to be aware of the possibility of thymic hyperplasia after chemotherapy to avoid misdiagnosis or over-staging of disease, as well as unnecessary biopsies, especially when the presenting anterior mediastinal mass was originally located near the thymus on CT scan. Mild FDG PET uptake was sufficient for the diagnosis of benign disease in the cases in this study.

Clinical value of FDG PET/CT in the diagnosis of suspected recurrent ovarian cancer: is there an impact of FDG PET/CT on patient management?

PURPOSE: The aim of this study was to evaluate the clinical value of FDG PET/CT in patients with suspected ovarian cancer recurrence as compared with diagnostic CT, and to assess the impact of the results of FDG PET/CT on treatment planning. METHODS: Included in this retrospective study were 60 patients with suspected recurrent ovarian cancer who had previously undergone primary debulking surgery and had been treated with adjuvant chemotherapy. Diagnostic CT and FDG PET/CT imaging were performed for all patients as clinically indicated. The changes in the clinical management of patients according to the results of FDG PET/CT were also analysed. RESULTS: FDG PET/CT was performed in 21 patients with a previously negative or indeterminate diagnostic CT scan, but an elevated CA-125 level, and provided a sensitivity of 95% in the detection of recurrent disease. FDG PET/CT revealed recurrent disease in 19 patients. In 17 of 60 patients, the indication for FDG PET/CT was an elevated CA-125 level and an abnormal diagnostic CT scan to localize accurately the extent of disease. FDG PET/CT scans correctly identified recurrent disease in 16 of the 17 patients, a sensitivity of 94.1%. Moreover, FDG PET/CT was performed in 18 patients with clinical symptoms of ovarian cancer recurrence, an abnormal diagnostic CT scan, but a normal CA-125 level. In this setting, FDG PET/CT correctly confirmed recurrent disease in seven patients providing a sensitivity of 100% in determining recurrence. In four patients, FDG PET/CT was carried out for the assessment of treatment response. Three of four scans were classified as true-negative indicating a complete response. In the other patient, FDG PET/CT identified progression of disease. In total, 45 (75%) of the 60 patients had recurrent disease, in 14 (31.1%) documented by histopathology and in 31 (68.9%) on clinical follow-up, while 15 (25%) had no evidence of recurrent disease. The overall sensitivity, specificity, accuracy, and positive and negative predictive value of FDG PET/CT were significantly superior to those of diagnostic CT (95.5% vs. 55.5%, 93.3% vs. 66.6%, 95% vs. 58.3%, 97.7% vs. 83.3%, 87.7% vs. 33.3%, respectively; p = 0.02) in the detection of recurrent ovarian cancer. FDG PET/CT changed the management in 31 patients (51.6%). It led to the use of previously unplanned treatment procedures in 19 patients (61.2%) and the avoidance of previously planned therapeutic procedures in 12 patients (38.8%). CONCLUSION: Our results confirm that FDG PET/CT is a superior posttherapy surveillance modality for the detection of recurrent ovarian cancer than diagnostic CT imaging. Furthermore, integrated FDG PET/CT was useful specifically in optimizing the treatment plan and it might play an important role in treatment stratification in the future.