Yukiko Arisaka

Detection of metastatic lesions from malignant pheochromocytoma and paraganglioma with diffusion-weighted magnetic resonance imaging: comparison with 18F-FDG positron emission tomography and 123I-MIBG scintigraphy

ObjectiveTo investigate the diagnostic features of whole-body diffusion-weighted magnetic resonance imaging (DWI) as compared with 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) and 123I-meta-iodo-benzyl guanidine scintigraphy (MIBG) on metastatic lesions of patients with malignant pheochromocytoma or paraganglioma.MethodsWe prospectively studied 11 patients with histologically confirmed pheochromocytoma/paraganglioma and possible metastatic lesions. FDG-PET, MIBG, and DWI examinations were performed within 1 week, and the images were visually interpreted. Abnormal positive uptake either on MIBG or on FDG-PET was considered as metastases. Abnormal high signal intensities on DWI were considered as metastases using conventional T1-and T2-weighted images as reference.ResultsFDG-PET and DWI demonstrated metastatic lesions in all 11 patients, but MIBG showed no metastatic lesions in two patients. The numbers of lymph node metastases depicted on FDG-PET, MIBG, and DWI were 19, 6, and 39; bone metastases were 50, 49, and 60; liver metastases were 9, 9, and 15; lung metastases were 5, 7, and 5, respectively. MIBG failed to demonstrate many metastatic lesions, which were demonstrated on FDG-PET or DWI, although two mediastinal lymph node metastases, three lung metastases, and six bone metastases, which were not seen on DWI, were clearly demonstrated on MIBG. DWI showed 15 liver metastases, but 6 of them were not seen on FDG-PET or MIBG.ConclusionsDWI may be particularly advantageous in depicting lymph node and liver metastases and may have a higher rate of detecting metastatic lesions when compared with MIBG or FDG-PET. The limitations of DWI were possible false-positive finding, and probable lower detectability of mediastinal lymph node and lung metastasis.

The assessment of biologic treatment in patients with rheumatoid arthritis using FDG-PET/CT

OBJECTIVES To evaluate whether there is a correlation between the differences in joint uptake of 2-[18F]-fluoro-2-deoxy-d-glucose ((18)F-FDG) and the improvement of clinical findings in RA patients undergoing anti-TNF therapies. METHODS Twenty-two patients who received anti-TNF therapies, including infliximab for 16 patients and etanercept for 6 patients, were assessed. PET with (18)F-FDG studies and clinical assessments were performed at baseline and 6 months after the initiation of therapy. The maximal standardized uptake value (SUV(max)) was used as a representative value for the assessment of the FDG uptake in the bilateral shoulder, elbow, wrist, hip, knee and ankle joints. Spearmans rank correlation test was applied to assess the correlation between the SUV and the clinical parameters. RESULTS The ΔSUV (12 joints), the difference in the SUV(max) of the affected 12 joints before and after treatment, was positively correlated with the ΔDAS28 (r = 0.609, P = 0.003), ΔDAS28-CRP (r = 0.656, P = 0.001) and Δtender joint count (TJC) (r = 0.609, P = 0.003). There were also significantly positive correlations between ΔSUV (8 joints); the difference in the SUV(max) of the bilateral shoulder, elbow, wrist and knee joints before and after treatment and the ΔDAS28 (r = 0.642, P = 0.001), ΔDAS28-CRP (r = 0.712, P < 0.001) and ΔTJC (r = 0.608, P = 0.003), respectively. CONCLUSION The FDG uptake observed in the inflamed RA joints may reflect disease activity. The FDG-PET response was correlated with the clinical response to the biologic treatment of RA.

Pulmonary artery intimal sarcoma: the role of 18 F-fluorodeoxyglucose positron emission tomography in monitoring response to treatment

We report the case of 58-year-old man with pulmonary artery intimal sarcoma. He initially presented with cough, right-sided chest pain, and shortness of breath. Although the diagnosis of pulmonary embolism had been considered, chest radiograph and pulmonary perfusion scintigraphy showed a mass in the right hilum and no perfusion in the right lung. 18F-fluorodeoxyglucose positron emission computed tomography (FDGPET) showed increased FDG uptake in the mass obstructing the right pulmonary artery. Fine-needle biopsy revealed a pathological diagnosis of pulmonary artery intimal sarcoma. The patient was successfully treated with radiotherapy and adjuvant chemotherapy. FDG-PET was used for monitoring the response to therapy.

Effects of Intratumoral Inflammatory Process on 18F-FDG Uptake: Pathologic and Comparative Study with 18F-Fluoro-α-Methyltyrosine PET/CT in Oral Squamous Cell Carcinoma

The accurate depiction of both biologic and anatomic profiles of tumors has long been a challenge in PET imaging. An inflammation, which is innate in the carcinogenesis of oral squamous cell carcinoma (OSCC), frequently complicates the image analysis because of the limitations of 18F-FDG and maximum standardized uptake values (SUVmax). New PET parameters, metabolic tumor volume (MTV) and total lesion glycolysis (TLG), as well as 18F-fluoro-α-methyltyrosine (18F-FAMT), a malignancy-specific amino acid–based PET radiotracer, are considered more comprehensive in tumor image analysis. Here, we showed the substantial effects of the intratumoral inflammatory process on 18F-FDG uptake and further study the possibility of MTV and TLG to predict both tumor biology (proliferation activity) and anatomy (pathologic tumor volume). Methods: 18F-FDG and 18F-FAMT PET images from 25 OSCC patients were analyzed. SUVmax on the tumor site was obtained. PET volume computerized-assisted reporting was used to generate a volume of interest to obtain MTV and TLG for 18F-FDG and total lesion retention (TLR) for 18F-FAMT. The whole tumor dissected from surgery was measured and sectioned for pathologic analysis of tumor inflammation grade and Ki-67 labeling index. Results: The high SUVmax of 18F-FDG was related to the high inflammation grade. The SUVmax ratio of 18F-FDG to 18F-FAMT was higher in inflammatory tumors (P < 0.05) whereas the corresponding value in tumors with a low inflammation grade was kept low. All 18F-FAMT parameters were correlated with Ki-67 labeling index (P < 0.01). Pathologic tumor volume predicted from MTV of 18F-FAMT was more accurate (R = 0.90, bias = 3.4 ± 6.42 cm3, 95% confidence interval = 0.77–6.09 cm3) than that of 18F-FDG (R = 0.77, bias = 8.1 ± 11.17 cm3, 95% confidence interval = 3.45–12.67 cm3). Conclusion: 18F-FDG uptake was overestimated by additional uptake related to the intratumoral inflammatory process, whereas 18F-FAMT simply accumulated in tumors according to tumor activity as evaluated by Ki-67 labeling index in OSCC.

CSF levels of Aβ1-38/Aβ1-40/Aβ1-42 and (11)C PiB-PET studies in three clinical variants of primary progressive aphasia and Alzheimer's disease.

Abstract Primary progressive aphasia (PPA) is a cognitive syndrome characterized by progressive and isolated language impairments due to neurodegenerative diseases. Recently, an international group of experts published a Consensus Classification of the three PPA clinical variants (naPPA, svPPA and lvPPA). We analyzed 24 patients with PPA by cognitive functions, neuroimaging (MRI, 99 mTc ECD-SPECT, 11C PiB-PET and FDG-PET) and cerebrospinal fluid (CSF) analysis (ptau-181, Aβ1-42, Aβ1-40 and Aβ1-38), to elucidate relationships between neuroimaging studies and biochemical findings in the three PPA clinical variants. Cognitive and speech functions were measured by mini-mental state examination and standard language test of aphasia. The patients with lvPPA showed significant decreases in CSF Aβ1-42 and ratios of Aβ1-42/Aβ1-40 and Aβ1-42/Aβ1-38, and significant increases in CSF ptau-181 and ratios of ptau-181/Aβ1-42 and ptau-181/Aβ1-38; these findings were similar to those of patients with Alzheimer’s disease (AD). We observed a higher frequency of the ApoE ε4 allele in the lvPPA patients relative to the two other PPA variants. In 11C PiB-PET of lvPPA patients, PiB positive findings were detected in cortices of frontal, temporal and parietal lobes and the posterior cingulate, where massive Aβ may accumulate due to AD. Our results of AD-CSF markers including Aβ1-38 and 11C PiB-PET in the lvPPA patients demonstrate a common pathological mechanism with the occurrence of AD.

Tumor-like accumulation on Tl-201 SPECT in subacute hemorrhagic cerebral infarction.

A 75-year-old woman was hospitalized for left hemiplegia. Intratumoral hematoma was considered likely based on the findings of computed tomographic (CT) images, and T1-201 SPECT was performed for further differentiation. Early SPECT images showed tumor-like accumulation in the right basal ganglia. However, the accumulation was washed out on delayed SPECT. Final diagnosis by a follow-up study was subacute hemorrhagic infarction. Although early T1-201 SPECT may show positive results for subacute hemorrhagic infarction, a delayed T1-201 SPECT can show a wash-out pattern that may be specific for this infarction. Early T1-201 SPECT may show tumor-like accumulation for subacute hemorrhagic infarction. This should be kept in mind in the analysis of T1-201 SPECT studies when cerebral infarction is being differentiated from brain tumor.

Correlation of tumor-related immunity with 18F-FDG-PET in pulmonary squamous-cell carcinoma

OBJECTIVES 2-Deoxy-2-[fluorine-18] fluoro-d-glucose with positron emission tomography (18F-FDG-PET) is a clinically useful tool for cancer evaluation. 18F-FDG accumulation in tumor cells is known to be correlated with the presence of glucose transporter 1 (GLUT1) and hypoxia-inducible factor-1α (HIF-1α). Although anti-programmed death-1 (PD-1) antibody treatments have been approved, no suitable predictor of significant responders has been identified. Based on the existing information, we investigated the relationship between tumor immunity (including PD-L1) and 18F-FDG uptake in patients with surgically resected pulmonary squamous-cell carcinoma (SQC). MATERIALS AND METHODS This study included 167 patients (153 men and 14 women) with SQC who underwent 18F-FDG PET. Tumor sections were stained by immunohistochemistry for GLUT1, HIF-1α, PD-L1, CD4, CD8, and Foxp3. The relationship between clinicopathological features and 18F-FDG uptake was analyzed. Students t-test, the χ2 test, non-parametric Spearmans rank test and the Kaplan-Meier method were used to show associations between variables. RESULTS The rate of positive PD-L1 expression was 79% (132/167), and PD-L1 expression was significantly associated with GLUT1 (P < 0.01), HIF-1α (P < 10-4), and CD8 (P < 1 × 10-3) expression. The SUVmax of 18F-FDG was significantly correlated with PD-L1 (P = 0.02) and GLUT1 (P < 0.01) expression. Multivariate analysis demonstrated that advanced stage, elevated PD-L1 expression, and elevated SUVmax were independent prognostic factors for predicting poor OS. Among patients with a high SUVmax, multivariate analysis confirmed that advanced stage and high PD-L1 expression were independent prognostic factors for poor OS; however, there was no significant difference among patients with a low SUVmax. CONCLUSION High SUVmax on 18F-FDG-PET is associated with PD-L1 expression but is an independent prognostic factor for OS in our population of surgically resected pulmonary squamous-cell carcinoma.

Preoperative Evaluation of Sellar and Parasellar Macrolesions by [18F]Fluorodeoxyglucose Positron Emission Tomography

OBJECTIVE Various diseases can occur in the sellar and suprasellar regions. The potential of [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) for the preoperative evaluation of sellar and parasellar lesions was investigated. METHODS A total of 49 patients aged 8-82 years with sellar and parasellar macroscopic lesions (≥10 mm) underwent FDG PET. Twenty-two patients had pituitary adenomas, including 14 nonfunctioning and 8 growth hormone-secreting adenomas. Eleven patients had craniopharyngiomas, including 5 adamantinomatous and 6 squamous-papillary types. Eight patients had chordoma, 4 had meningioma, and 4 had a Rathke cleft cyst. The maximum standardized uptake value (SUVmax), and the ratio of the SUVmax in the tumor to the mean standardized uptake value in the normal cortex (T/N ratio) or in the normal white matter (T/W ratio) were calculated. The relationships between SUVmax, T/N ratio, and T/W ratio, and lesion disease were evaluated. RESULTS Uptakes of FDG, including SUVmax, T/N ratio, and T/W ratio, were lower in chordoma and Rathke cleft cyst compared with pituitary adenoma. SUVmax, T/N ratio, and T/W ratio of nonfunctioning adenoma were significantly higher than those of growth hormone-secreting adenoma. SUVmax, T/N ratio, and T/W ratio of squamous-papillary type were significantly higher than those of the adamantinomatous type of craniopharyngioma. CONCLUSIONS FDG PET is useful for the preoperative diagnosis of sellar and parasellar macrolesions. High uptake in nonfunctioning pituitary adenoma, and low uptake in chordoma are significant. The difference in FDG uptake dependent on the histologic subtype may be related to the specific genetics of the craniopharyngioma subtype.

Clinical value of fluorine-18α-methyltyrosine PET in patients with gliomas: comparison with fluorine-18 fluorodeoxyglucose PET

BackgroundWe investigated the relationship between metabolic activity and histological features of gliomas using fluorine-18α-methyltyrosine (18F-FAMT) positron emission tomography (PET) compared with fluorine-18 fluorodeoxyglucose (18F-FDG) PET in 38 consecutive glioma patients. The tumor to normal brain ratios (T/N ratios) were calculated, and the relationships between T/N ratio and World Health Organization tumor grade or MIB-1 labeling index were evaluated. The diagnostic values of T/N ratios were assessed using receiver operating characteristic (ROC) curve analyses to differentiate between high-grade gliomas (HGGs) and low-grade gliomas (LGGs).ResultsMedian T/N ratio of 18F-FAMT PET was 2.85, 4.65, and 4.09 for grade II, III, and IV gliomas, respectively, with significant differences between HGGs and LGGs (p = 0.006). Both T/N ratio (p = 0.016) and maximum standardized uptake value (p = 0.033) of 18F-FDG PET showed significant differences between HGGs and LGGs. ROC analysis yielded an optimal cut-off of 3.37 for the T/N ratio of 18F-FAMT PET to differentiate between HGGs and LGGs (sensitivity 81%, specificity 67%, accuracy 76%, area under the ROC curve 0.776). Positive predictive value was 84%, and negative predictive value was 62%. T/N ratio of 18F-FAMT PET was not correlated with MIB-1 labeling index in all gliomas, whereas T/N ratio of 18F-FDG PET was positively correlated (rs = 0.400, p = 0.013). Significant positive correlation was observed between T/N ratios of 18F-FDG and 18F-FAMT (rs = 0.454, p = 0.004), but median T/N ratio of 18F-FAMT PET was significantly higher than that of 18F-FDG PET in all grades of glioma.ConclusionsThe T/N ratio of 18F-FAMT uptake has high positive predictive value for detection of HGGs. 18F-FAMT PET had higher T/N ratio, with better tumor-normal brain contrast, compared to 18F-FDG PET in both LGGs and HGGs. Therefore, 18F-FAMT is a useful radiotracer for the preoperative visualization of gliomas.