Tatsuo Torizuka

18F-FDG PET in the detection of extrahepatic metastases from hepatocellular carcinoma.

BackgroundPositron emission tomography (PET) with 18F-fluoro-2-deoxy-d-glucose (18F-FDG) is useful in detecting distant metastases from a variety of malignancies. However, its efficiency in detecting distant metastases from hepatocellular carcinoma (HCC) has not been investigated. The aim of this study was to evaluate the usefulness of 18F-FDG PET for the detection of extrahepatic metastases from HCC.MethodsNineteen patients suspected of having extrahepatic HCC underwent 18F-FDG PET. Fourteen patients (group A) had extrahepatic lesions, which were detected by conventional studies. In five patients (group B), conventional imaging showed no extra- or intrahepatic lesions, but the tumor marker levels were elevated. The PET results were compared with those obtained by histopathology or by clinical follow-up.ResultsThe detection rate of 18F-FDG PET was 83% (24 of 29 metastases) for extrahepatic metastases larger than 1 cm in greatest diameter and 13% (1 of 8 metastases) for lesions less than or equal to 1 cm. PET revealed two bone metastases not depicted by bone scan, and detected the nodal metastasis and intestinal metastases inconclusive on computed tomography. Extrahepatic lesions were resected in 5 patients of group A on the basis of PET findings. In all patients of group B, PET results were true negative for extrahepatic metastases, but HCCs were detected in the liver within 4 months in 4 patients. These were no false-positive lesions in either group.ConclusionsThis preliminary study suggested that 18F-FDG PET could provide additional information and contribute to the management of HCC patients suspected of having extrahepatic metastases.

Bronchial artery embolization for hemoptysis: Immediate and long-term results

The purpose of this study was to evaluate the immediate and long-term results in 63 patients who underwent transarterial embolization for control of hemoptysis. Overall immediate success rate was 86.1%. At long-term follow-up 50% of patients showed complete remission, 22% partial remission, and 28% recurrent hemoptysis. Hemoptysis remained controlled for a mean of 22 months and a median of 14 months. The long-term results among four disease groups differed substantially. Patients with bronchiectasis showed the best results, followed by those with idiopathic disease and with inflammation; patients with neoplasm showed the worst results.

Early therapy monitoring with FDG-PET in aggressive non-Hodgkin’s lymphoma and Hodgkin’s lymphoma

This study was designed to determine the value of 2-[fluorine-18]-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) in the early assessment of therapy response in lymphoma patients. We studied 20 patients with pathologically proven lymphoma, including 17 patients with aggressive non-Hodgkin’s lymphoma and three patients with Hodgkin’s lymphoma. All patients underwent whole-body FDG-PET imaging at baseline and after 1–2 cycles of chemotherapy. PET images were analysed visually and quantitatively by calculating the standardised uptake value (SUV). In each patient, we measured the SUV of the tumour demonstrating the highest FDG uptake at baseline study and the SUV of the same tumour after 1–2 cycles of therapy. The achievement of complete response was assessed on the basis of a combination of clinical findings and the results of conventional imaging modalities. Follow-up of progression-free survival (PFS) was obtained for the validation of PET data. Of the 20 patients, ten achieved complete remission at the completion of chemotherapy and the other ten did not respond to chemotherapy. Of the ten responders, four are still in remission (PFS 24–34 months) while the other six have relapsed (PFS 8–16 months). For the prediction of 24-month clinical outcome, visual analysis of PET after 1–2 cycles showed high sensitivity (87.5%) and accuracy (80%) but low specificity (50%). Comparison with the baseline SUVs revealed that the responders showed a significantly greater percent reduction in SUV after 1–2 cycles of therapy as compared with the non-responders (81.2%±9.5% vs 35.0%±20.2%, P<0.001). In addition, using 60% reduction as a cut-off value, the responders were clearly separated from the non-responders, with the exception of one non-responder. In conclusion, when performed early during chemotherapy, FDG-PET may be predictive of clinical outcome and allows differentiation of responders from non-responders in cases of aggressive lymphoma.

11C-Choline Positron Emission Tomography in Prostate Cancer: Primary Staging and Recurrent Site Staging

Objectives: To evaluate the usefulness of 11C-choline positron emission tomography (PET) for primary staging and re-staging of prostate cancer. Patients and Methods:11C-choline PET, a total of 22 scans, was performed on 13 patients with histologically proven prostate cancer in primary staging (n = 6) and recurrent site staging; following radical prostatectomy (n = 5) and following radiation therapy (n = 3). In 1 patient, 11C-choline PET was performed in both primary staging and re-staging. Also, 3 patients histologically proven to have no malignant prostate were included. Results: Because urinary 11C-choline activity was low, it did not interfere with the visualization of pelvic structures. 11C-choline PET visualized normal prostate with a mean SUV of 2.99 (range 2.27–3.68) and primary prostate cancer as a hot spot in 5/6 scans with a mean SUV of 4.21 (range 2.99–6.2). In re-staging, 11C-choline PET was true positive in 9/16 scans and true negative in 2/16 scans. 5/16 scans in 2 patients were false negative with negative conventional imaging. Conclusions: In primary staging, 11C-choline PET may not be of use because of no reliable differential 11C-choline uptake of BPH and prostate cancer. On the other hand, 11C-choline PET may be of value in recurrent site staging and monitoring for the prostate cancer.

Preoperative Positron Emission Tomography with Fluorine-18-Fluorodeoxyglucose is Predictive of Prognosis in Patients with Hepatocellular Carcinoma after Resection

Background:Hepatocellular carcinomas (HCCs) accumulate fluorine-18 fluorodeoxyglucose (FDG) to various degrees. The standardized uptake values (SUVs) of FDG-positron emission tomography (PET) in high-grade HCCs are significantly higher than those in low-grade HCCs.Aim:The aim of this study was to evaluate the possible usefulness of FDG-PET in predicting the prognosis of HCC patients after resection. We analyzed the relationship between the tumor to non-tumor SUV ratios (SUV ratio) and surgical outcome in 31 patients.Results:Of the 31 cases of HCC studied, seven (23%) exhibited SUV ratios greater than 2, as the cutoff value. The percentage of patients with poorly differentiated HCC was greater in the higher SUV ratio group (SUV ratio >2) than in the lower SUV ratio group (SUV ratio <2) (57 vs. 32%). The overall survival was significantly longer in the lower SUV ratio group than in the higher SUV ratio group (5-year-survival rate: 63 vs. 29% P = 0.006) (median survival time: 2310 vs.182 days).Conclusion:The SUV ratio was related significantly to disease-related death as well as other predictive factors, including the number of tumors, the size, stage, and involvement of vessels, and the involvement of the capsule. Consequently, we conclude that the SUV ratio provides information of prognostic relevance in patients with HCC before surgery.

Prognostic value of 18F-FDG PET in patients with head and neck squamous cell cancer.

OBJECTIVE This study was designed to assess whether tumor uptake of (18)F-FDG (FDG) expressed as the standardized uptake value (SUV) can be used to predict survival in patients with head and neck cancer. Furthermore, a prognostic maximum SUV was determined with univariate and bivariate analyses. CONCLUSION Low SUVs (</= 7.0) predicted significantly higher rates of 2-year local control (p = 0.0067) and disease-free survival (p = 0.0051) as compared with high SUVs (> 7.0). In the Cox proportional hazards model, tumor SUV was a significant and independent predictor of local control (p = 0.022) and disease-free survival (p = 0.019). In addition, in the group of high SUV, high T stage was more associated with poorer outcome than low T stage (p = 0.0502). Therefore, patients with higher tumor FDG uptake should be considered for a more aggressive treatment approach.

Presynaptic and postsynaptic dopaminergic binding densities in the nigrostriatal and mesocortical systems in early Parkinson's disease: a double-tracer positron emission tomography study.

To investigate changes in the relation between presynaptic and postsynaptic dopaminergic functions in vivo in both nigrostriatal and mesocortical systems in Parkinsons disease (PD), 10 drug‐naive early PD patients were studied twice using positron emission tomography with [11C]CFT (dopamine transporter probe) followed by [11C]SCH 23390 (D1 receptor probe). Regional binding potentials (k3/k4) of [11C]CFT and [11C]SCH 23390 in the striatum (nigrostriatal system) and the orbitofrontal cortex (mesocortical system) were estimated by compartment analyses. Levels of [11C]CFT k3/k4 in the two projection areas were shown to be significantly lower in PD, whereas [11C]SCH 23390 levels remained unchanged. Regression analysis showed that estimates of CFT k3/k4 were positively correlated with those of SCH 23390 k3/k4 in the striatum in normal control, whereas the two binding estimates were less positively correlated in the caudate and inversely correlated in the putamen in PD. No significant correlation was observed in the orbitofrontal cortex in both groups. These results indicated that dopamine transporters and D1 receptors change in parallel in the normal striatal synapses, but the association becomes asymmetrical because of reduction in presynaptic and relative elevation in postsynaptic markers in PD. Alterations in synaptic parallel regulation in the nigrostriatal system might reflect early pathophysiology in the parkinsonian brain.

Effect of Simple Motor Performance on Regional Dopamine Release in the Striatum in Parkinson Disease Patients and Healthy Subjects: A Positron Emission Tomography Study

To investigate changes in dopamine release in the striatum during motor exercise in human subjects with and without striatal dopamine denervation, eight healthy subjects and eight patients with Parkinson disease (PD) were measured during unilateral foot extension/flexion movement using positron emission tomography with [11C]raclopride. Five subjects in each group were later scanned in the resting condition. Estimation of binding potential (k3/k4) of [11C]raclopride was based on Logan plot method. Significant reductions in [11C]raclopride k3/k4 were found in the dorsal putamen contralateral to the exercise side in the healthy group and ipsilaterally in the PD group. Spearman rank correlation analysis showed that [11C]raclopride k3/k4 correlated inversely with the decrease in performance (velocity and motion range) in the dorsal putamen contralaterally in the healthy group and ipsilaterally in the PD group. These results suggest that simple but laborious motor exercise (motor stimulation) generates significant dopamine release in the dorsal striatum contralateral to the motor execution in humans. Lack of the crossed pattern and ipsilateral increase in dopamine release in the dorsal striatum during the unilateral limb movement may reflect the pathophysiology for hypokinetic and insufficient coordinating movement in PD.

Positron emission tomography with 18F-fluoro-2-deoxyglucose for the detection of recurrent ovarian cancer.

BackgroundRecurrent ovarian cancer is refractory and resistant to treatment in most patients, and no effective treatment for it has been established. Starting a treatment when tumors still consist of micro foci may contribute to improvement of prognosis. Therefore, the early diagnosis of relapse is important.MethodsAmong patients with epithelial ovarian cancer in whom initial treatment achieved remission between April 1998 and December 2003, those patients in whom the cancer-related antigen (CA)125 level was increased during the subsequent follow-up period, or those who showed abnormal computed tomography (CT)/magnetic resonance imaging (MRI) findings despite normal CA125 levels, were examined by 18F-fluoro-2-deoxyglucose – positron emission tomography (FDG-PET). We compared the rates of accurate diagnosis of recurrence achieved using CT/MRI, CA125, and FDG-PET in patients with a definitive diagnosis of relapse.ResultsWe investigated 29 patients with epithelial ovarian cancer. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of FDG-PET were 84.6% (22/26), 100% (3/3), 100% (22/22), 42.9% (3/7), and 86.2% (25/29), respectively. These values were higher than the corresponding values obtained using CT/MRI or CA125 levels.ConclusionFDG-PET may be very useful for identifying sites of recurrent ovarian cancer, although this procedure had a low NPV because of the high rate of false-negative findings for micro or cystic lesions.

Single 20-Second Acquisition of Deep-Inspiration Breath-Hold PET/CT: Clinical Feasibility for Lung Cancer

This study was designed to compare tumor 18F-FDG uptake between a single 20-s acquisition of deep-inspiration breath-hold PET/CT and free-breathing PET/CT for lung cancer. Methods: Before the clinical study, a phantom study was performed to determine the optimum breath-hold time for the PET scan. We studied 47 patients with lung cancer who underwent free-breathing PET/CT with the standard clinical protocol, followed by deep-inspiration breath-hold PET/CT of the thorax. In breath-hold PET/CT, the patients were asked to hold their breath in deep inspiration for 10 s during the CT scan and for 20 s during the PET scan. Maximum tumor 18F-FDG standardized uptake value (SUVmax) was measured in free-breathing PET and breath-hold PET, and the percentage difference between these 2 values was calculated. Results: Breath-hold PET showed a significant increase in SUVmax, as compared with free-breathing PET (8.26 ± 4.59 vs. 11.25 ± 7.24, P < 0.0001). The mean difference in SUVmax was 39.5% ± 43.4%, and the range was 2.9%−248.3%. The difference in SUVmax was significant when compared between tumors in the upper lung (n = 22) and tumors in the lower lung (n = 25) (24.4% ± 17.7% vs. 52.9% ± 54.3%, P = 0.0077). The mean tumor size of the group with a high SUVmax difference (n = 13) was significantly smaller than that of the group with a low SUVmax difference (n = 34) (2.45 ± 0.87 cm vs. 3.21 ± 1.22 cm, P = 0.043), using a cutoff of 39.5%. Conclusion: The single 20-s acquisition of breath-hold PET/CT enabled more precise measurement of SUVmax, especially in the lower lung field and for small tumors, which may be affected by respiratory motion. This technique is feasible in the clinical setting and requires only a minor increase in examination time.