Kimiichi Uno

Prognostic significance of [18F]fluorodeoxyglucose uptake on positron emission tomography in patients with pathologic stage I lung adenocarcinoma

[18F]Fluoro‐2‐deoxyglucose uptake on positron emission tomography (FDG‐PET) has been frequently used for diagnosis and staging of lung cancer. The prognostic significance of FDG uptake on PET was evaluated in patients with pathologic Stage I lung adenocarcinoma (tumor stages were based on the TNM classification of the International Union Against Cancer).

Long fasting is effective in inhibiting physiological myocardial 18F-FDG uptake and for evaluating active lesions of cardiac sarcoidosis

BackgroundF-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a promising modality for detecting active lesions of cardiac sarcoidosis (CS). However, determining whether 18F-FDG uptake in the myocardium is physiological is challenging due to metabolic shift in myocardial cells. Although methods for inhibiting physiological myocardial 18F-FDG uptake have been proposed, no standard methods exist. This study therefore aimed to compare the effect of an 18-h fast (long fasting (LF)) with heparin loading plus a 12-h fast (HEP) before 18F-FDG PET scan.MethodsWe analyzed the effects of LF and HEP on the inhibition of physiological myocardial 18F-FDG uptake in healthy subjects (18 in HEP and 19 in LF) and in patients with known or suspected CS (96 in HEP and 69 in LF). In CS, the lower uptake of 18F-FDG in the myocardium was evaluated. A visual four-point scale was used to assess myocardial 18F-FDG uptake in comparison with hepatic uptake (1 lower, 2 similar, 3 somewhat higher, 4 noticeably higher).ResultsMyocardial 18F-FDG uptake was 1.68 ± 1.06 in LF and 3.17 ± 1.16 in HEP in healthy subjects (p < 0.0001), whereas it was 1.48 ± 0.99 in LF and 2.48 ± 1.33 in HEP in CS patients (p < 0.0001). Logistic regression and regression trees revealed the LF was the most effective in inhibiting myocardial 18F-FDG uptake. In addition, serum free fatty acid levels on intravenous 18F-FDG injection were a possible biomarker.ConclusionsLF is effective in inhibiting myocardial 18F-FDG uptake, and consequently, it could be useful for evaluating active lesions of CS in 18F-FDG PET images.

FDG-PET for predicting the prognosis of malignant lymphoma

To evaluate the usefulness of FDG-PET as a predictor of prognosis, 34 patients with untreated malignant lymphoma in the head and neck region were studied. After FDG-PET and treatment, they were observed from 15 to 50 months. Tumors which were aggressive and resistant to treatment tended to show high uptake of FDG. The survival rate of patients with high uptake of FDG, DAR > 8, was lower than the rate of the other patients. It is considered to be useful to add FDG uptake of the tumor to other prognostic factors for predicting the prognosis.

Non-Hodgkin's lymphoma confined to the nasal cavity: Its relationship to the polymorphic reticulosis and results of radiation therapy

From 1975 through 1988, nine patients with locally confined nasal non-Hodgkins lymphoma (NHL) were treated with radiation therapy in the Department of Radiology, Chiba University Hospital. Immunohistochemical study disclosed that all NHLs have T-lineage. Additionally, unique histological pictures of polymorphism, angiodestruction, and necrosis were seen in most of cases. These three findings are the histological features of polymorphic reticulosis (PMR), which is the main cause of lethal midline granuloma and has recently been shown to belong to T-cell malignancy. Therefore, it is concluded that the nasal T-cell NHL and PMR are really a single disease entity. The predominance of the T-cell lymphoma in the nasal cavity as well as its histological distinctness clearly indicate that the head and neck extranodal NHL cannot be discussed together. Although the disorder was considered to be locally limited at presentation, only 3 of the 9 patients with nasal NHL could be induced into long-term remission with involved field radiotherapy. The distant extranodal spread was the primary cause of failure. Multimodality treatment using intensive chemotherapy might improve the prognosis of nasal NHL.

18F-fluorodeoxyglucose and 11C-acetate positron emission tomography are useful modalities for diagnosing the histologic type of thymoma

The objective of this study was to clarify the usefulness of positron emission tomography (PET) using18F‐fluorodeoxyglucose (FDG) and carbon 11‐labeled acetate (AC) for predicting the histologic types and tumor invasiveness of thymoma in a multicenter study.

Analysis of various malignant neoplasms detected by FDG-PET cancer screening program: based on a Japanese Nationwide Survey.

ObjectiveThe most distinctive feature of FDG-PET cancer screening program is the ability to find various kinds of malignant neoplasms in a single test. The aim of this survey is to clarify the range and frequency of various malignant neoplasms detected by FDG-PET cancer screening performed in Japan.Methods“FDG-PET cancer screening” was defined as FDG-PET or positron emission tomography and computed tomography (PET/CT) scan with or without other tests performed for cancer screening of healthy subjects. This survey was based on a questionnaire regarding FDG-PET cancer screening. We analyzed the situation of 9 less frequently found malignant neoplasms including malignant lymphoma, malignancy of head and neck, esophagus, hepatobiliary and gallbladder, pancreas, kidney, cervical and uterine, ovary, and bladder.ResultsThe detailed information of subjects with the suspected 9 kinds of malignant neoplasms mentioned above in the FDG-PET cancer screening program was studied in a total of 1,219 cases from 212 facilities. A statistical significance between PET/CT and PET was found in relative sensitivity and PPV for renal cell cancer. Malignant lymphoma was frequently of indolent type, suspected head and neck cancers had many false-positive results, and pancreatic cancer detected in this program was often in the advanced stage even in asymptomatic subjects. The recommendation of combined screening modality to PET or PET/CT was as follows: gastric endoscopy for assessing early esophageal cancer; abdominal ultrasound for screening hepatobiliary and gallbladder cancer; pelvic magnetic resonance imaging for assessing gynecological and pelvic cancers; and the CA125 blood test for screening ovarian cancer. Delayed image was helpful depending on the type of suspected malignant neoplasm.ConclusionWe analyzed various types of malignant neoplasms detected by the FDG-PET cancer screening program and presented recommended combination of examinations to cover FDG-PET and PET/CT.

Increased activity on radiocolloid scintigraphy in splenic hamartoma

A higher uptake of radiocolloid in a splenic tumor than in the rest of the spleen was observed in a 17-year-old boy. The pathologic diagnosis of the surgically resected tumor was hamartoma composed of anomalous mixtures of splenic elements, and radiocolloid was considered to be distributed to reticuloendothelial cells in the tumor. Radiocolloid scintigraphy, which can demonstrate the function of the reticuloendothelial system, is helpful in the diagnosis of splenic hamartoma.

11C-Acetate can be Used in Place of 18F-Fluorodeoxyglucose for Positron Emission Tomography Imaging of Non-small Cell Lung Cancer with Higher Sensitivity for Well-Differentiated Adenocarcinoma

Objectives: Although positron emission tomography (PET) using 18F-fluorodeoxy-glucose (FDG) frequently gives false-negative results for slow-growing tumors, 11C-acetate (AC)-PET has been reported to be able to detect them. To determine the usefulness of AC-PET for imaging non-small cell lung cancers (NSCLCs), the sensitivity and specificity were compared between the AC-PET and FDG-PET with a multicenter study. Materials and Methods: A total of 284 pulmonary lesions (227 NSCLCs and 57 benign lesions) were examined using both AC-PET and FDG-PET before surgery at seven Japanese institutes. The AC- or FDG-uptake in each lesion were quantitatively measured using the contrast ratio of the standard uptake value between the lesions and the contralateral lung. Results: The sensitivity of AC-PET for diagnosing NSCLC was 0.71, which was significantly higher than the value of 0.57 obtained by FDG-PET (p < 0.001). No significant difference in the specificity was seen between AC- and FDG-PET. For the 146 well-differentiated adenocarcinomas, the sensitivity of AC-PET was 0.62, which was significantly higher than the value of 0.37 obtained by FDG-PET (p < 0.001). Of the 51 moderately- or poorly-differentiated adenocarcinomas and 30 nonadenocarcinomas, there was no significant difference of sensitivity between AC- and FDG-PET. Conclusions: AC-PET could be used in place of FDG-PET for imaging NSCLC, with higher sensitivity for well-differentiated adenocarcinoma compared with FDG-PET.

FDG-PET for the evaluation of tumor viability after anticancer therapy.

To evaluate positron emission tomography with18F-fluorodeoxy glucose (FDG-PET) as an diagnostic tool to determine tumor viability after anticancer therapy, fourteen patients were examined by FDG-PET after the end of the treatment. The lesions with residual viable tumor cells showed higher uptake of FDG than surrounding normal soft tissue. The lesions, in which tumor viability was lost or very low, showed higher uptake of FDG in four cases and similar uptake to normal soft tissue in three cases. The residual increased uptake of FDG was considered to be caused by remaining tumor cells and/or inflammatory reaction to anticancer treatment. FDG-PET after anticancer treatment should be interpreted by considering the reaction due to the treatment and the partial volume artifact of PET caused by the limited spatial resolution.

Optimization of Butterworth filter for brain SPECT imaging

A method has been described to optimize the cutoff frequency of the Butterworth filter for brain SPECT imaging. Since a computer simulation study has demonstrated that separation between an object signal and the random noise in projection images in a spatial-frequency domain is influenced by the total number of counts, the cutoff frequency of the Butterworth filter should be optimized for individual subjects according to total counts in a study. To reveal the relationship between the optimal cutoff frequencies and total counts in brain SPECT study, we used a normal volunteer and99mTc hexamethyl-propyleneamine oxime (HMPAO) to obtain projection sets with different total counts. High quality images were created from a projection set with an acquisition time of 300-seconds per projection. The filter was optimized by calculating mean square errors from high quality images visually inspecting filtered reconstructed images. Dependence between total counts and optimal cutoff frequencies was clearly demonstrated in a nomogram. Using this nomogram, the optimal cutoff frequency for each study can be estimated from total counts, maximizing visual image quality. The results suggest that the cutoff frequency of Butterworth filter should be determined by referring to total counts in each study.