Simulation of supply chain disruptions considering establishments and power outages.

In this paper, we simulate the economic loss resulting from supply chain disruptions triggered by the Great East Japan Earthquake (GEJE) in 2011, applying data from firm-level supply chains and establishment-level attributes to an agent-based model. To enhance the accuracy of the simulation, we extend data and models in previous studies in four ways. First, we identify the damage to production facilities in the disaster-hit regions more accurately by using establishment-level census and survey data and geographic information system (GIS) data on the damages caused by the GEJE and subsequent tsunami. Second, the use of establishment-level data enables us to capture supply chains between non-headquarter establishments in disaster-hit regions and establishments in other regions. Third, we incorporate the effect of power outages after the GEJE on production reduction, which exacerbated the effect of the supply chain disruption, particularly in the weeks immediately after the GEJE. Finally, our model incorporates sectoral heterogeneity by employing sector-specific parameters. Our findings indicate that the extended method can significantly improve the accuracy of predicting the domestic production after the GEJE, particularly due to the first three improvements utilizing various data sources, not because of the use of more sector-specific parameters. Our method can be applied to predict the economic effect of future disasters, such as the Nankai Trough earthquake, on each region more precisely.

Open source code for behavior analysis in rodents.

AIM: We have conducted a series of behavioral tests, which cover a broad range of behavioral domains, on various strains of genetically engineered mice. For the behavioral screening, we have been using Image J plugins that we developed for most of the tests in the battery. Our behavioral analysis system with the plugins enables systematic and automated image analysis of behavior. The plugins are freely available on the "Mouse Phenotype Database" website (http://www.mouse-phenotype.org/software.html). Here, we release the source code of the plugins in a Git repository with the aim of promoting their use and expanding their functionality. METHODS: We published the source code of the Image J plugins for behavioral analysis at Git repository (https://github.com/neuroinformatics). The source code for light/dark transition, elevated plus maze, open filed, T-maze, and fear conditioning tests was made publicly available in the repository. CONCLUSIONS: The source code of the plugins for the behavioral tests as well as the pre-compiled binaries can be freely obtained. The open source code could promote the development and modification of the plugins for additional behavioral indices in these tests and for other behavioral tests.

ViBrism DB: an interactive search and viewer platform for 2D/3D anatomical images of gene expression and co-expression networks.

Understanding anatomical structures and biological functions based on gene expression is critical in a systemic approach to address the complexity of the mammalian brain, where >25 000 genes are expressed in a precise manner. Co-expressed genes are thought to regulate cell type- or region-specific brain functions. Thus, well-designed data acquisition and visualization systems for profiling combinatorial gene expression in relation to anatomical structures are crucial. To this purpose, using our techniques of microtomy-based gene expression measurements and WebGL-based visualization programs, we mapped spatial expression densities of genome-wide transcripts to the 3D coordinates of mouse brains at four post-natal stages, and built a database, ViBrism DB (http://vibrism.neuroinf.jp/). With the DB platform, users can access a total of 172 022 expression maps of transcripts, including coding, non-coding and lncRNAs in the whole context of 3D magnetic resonance (MR) images. Co-expression of transcripts is represented in the image space and in topological network graphs. In situ hybridization images and anatomical area maps are browsable in the same space of 3D expression maps using a new browser-based 2D/3D viewer, BAH viewer. Created images are shareable using URLs, including scene-setting parameters. The DB has multiple links and is expandable by community activity.

Percutaneous radiofrequency ablation for patients with malignant lung tumors: a phase II prospective multicenter study (JIVROSG-0702).

PURPOSE: This prospective multicenter study aimed to evaluate the efficacy and safety of percutaneous radiofrequency (RF) ablation for lung cancer. MATERIALS AND METHODS: From May 2008 to April 2012, 33 patients (26 men, 7 women; mean age 70.5 years) were enrolled. RF ablation was performed using an internally cooled or expandable multitined electrode. The primary endpoint was complete response (CR) determined using (18)F fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) performed 6 months after RF ablation. The secondary endpoint was the incidence and grade of adverse events (AEs) evaluated using the Common Toxicity Criteria for Adverse Events, version 3.0. RESULTS: All patients underwent RF ablation and had efficacy analyses evaluated; however, FDG-PET/CT images before RF ablation were not available for two patients. The CR rate was 68 % (21 of 31 patients). One patient had a grade 5 AE unrelated to RF ablation. Grade ≥3 AEs occurred in 12 % of patients. During the follow-up period (median 37 months; range 1-55 months), five patients developed local tumor progression and nine (29 %) died. Overall survival at 1, 2, and 3 years was 97, 82, and 74 %, respectively. CONCLUSION: Percutaneous RF ablation is a safe, feasible, and effective treatment for small malignant lung tumors.

MRI Findings of Inverted Urothelial Papilloma of the Bladder.

OBJECTIVE: The objective of this study was to characterize MRI findings of inverted urothelial papilloma of the bladder. MATERIALS AND METHODS: Data pertaining to 16 patients with 18 pathologically proven inverted urothelial papillomas of the bladder who had undergone MRI were retrospectively collected from seven institutions. The shape and surface characteristics of the tumors were evaluated using T2-weighted MR images. In addition, the signal intensity of inverted urothelial papillomas was visually assessed on T1-weighted, T2-weighted, and DW images and on early and delayed phase contrast-enhanced images. RESULTS: The shape of the 18 inverted urothelial papillomas of the bladder was classified as polypoid with a stalk for 16 tumors (89%) and polypoid without a stalk for two tumors (11%). All stalks were surrounded by urine in the bladder. A total of 15 of the tumor surfaces (83%) were nonpapillary and three (17%) were papillary. All 12 of the inverted urothelial papillomas for which evaluable T1-weighted images were available were isointense with the bladder wall. The lesions had a slightly higher signal intensity than the bladder wall in 15 of the patients (83%) and showed isointensity with the bladder wall in three patients (17%). A total of three patients (17%) had tiny hyperintense foci noted on T2-weighted images. All 16 of the inverted urothelial papillomas examined by DWI had very high signal intensity. All 13 of the lesions for which early phase images were obtained using dynamic contrast-enhanced MRI showed strong enhancement. When compared with early phase images, delayed phase images of the same 13 lesions showed that enhancement was stronger in two lesions (15%), similar in six lesions (46%), and weaker in five lesions (38%). CONCLUSION: On MRI, the typical appearance of inverted urothelial papillomas of the bladder is a polypoid shape with a nonpapillary surface and a thin short stalk surrounded by urine. Cystic foci are also occasionally seen within the tumor.

The Maximum standardized uptake value is more reliable than size measurement in early follow-up to evaluate potential pulmonary malignancies following radiofrequency ablation.

We retrospectively evaluated the accumulation of fluorodeoxy glucose (FDG) in pulmonary malignancies without local recurrence during 2-year follow-up on positron emission tomography (PET)/computed tomography (CT) after radiofrequency ablation (RFA). Thirty tumors in 25 patients were studied (10 non-small cell lung cancers;20 pulmonary metastatic tumors). PET/CT was performed before RFA, 3 months after RFA, and 6 months after RFA. We assessed the FDG accumulation with the maximum standardized uptake value (SUVmax) compared with the diameters of the lesions. The SUVmax had a decreasing tendency in the first 6 months and, at 6 months post-ablation, FDG accumulation was less affected by inflammatory changes than at 3 months post-RFA. The diameter of the ablated lesion exceeded that of the initial tumor at 3 months post-RFA and shrank to pre-ablation dimensions by 6 months post-RFA. SUVmax was more reliable than the size measurements by CT in the first 6 months after RFA, and PET/CT at 6 months post-RFA may be more appropriate for the assessment of FDG accumulation than that at 3 months post-RFA.

Detectability of colorectal neoplasia with fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography (FDG-PET/CT).

BACKGROUND: The purpose of this study was to analyze the detectability of colorectal neoplasia with fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT). METHODS: Data for a total of 492 patients who had undergone both PET/CT and colonoscopy were analyzed. After the findings of PET/CT and colonoscopy were determined independently, the results were compared in each of the six colonic sites examined in all patients. The efficacy of PET/CT was determined using colonoscopic examination as the gold standard. RESULTS: In all, 270 colorectal lesions 5 mm or more in size, including 70 pathologically confirmed malignant lesions, were found in 172 patients by colonoscopy. The sensitivity and specificity of PET/CT for detecting any of the colorectal lesions were 36 and 98%, respectively. For detecting lesions 11 mm or larger, the sensitivity was increased to 85%, with the specificity remaining consistent (97%). Moreover, the sensitivity for tumors 21 mm or larger was 96% (48/50). Tumors with malignant or high-grade pathology were likely to be positive with PET/CT. A size of 10 mm or smaller [odds ratio (OR) 44.14, 95% confidence interval (95% CI) 11.44-221.67] and flat morphology (OR 7.78, 95% CI 1.79-36.25) were significant factors that were associated with false-negative cases on PET/CT. CONCLUSION: The sensitivity of PET/CT for detecting colorectal lesions is acceptable, showing size- and pathology-dependence, suggesting, for the most part, that clinically relevant lesions are detectable with PET/CT. However, when considering PET/CT for screening purposes caution must be exercised because there are cases of false-negative results.

The usefulness of pre-radiofrequency ablation SUV(max) in 18F-FDG PET/CT to predict the risk of a local recurrence of malignant lung tumors after lung radiofrequency ablation.

The aim of the present study was to assess the diagnostic usefulness of Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in the prediction of local recurrence of malignant lung tumors by analyzing the pre-radiofrequency ablation (RFA) maximal standardized uptake value (SUV(max)). We performed a historical cohort study of consecutive malignant lung tumors treated by RFA from January 2007 to May 2008 at Okayama University Hospital. We selected only lung tumors examined by PET/CT within 90 days before RFA and divided them (10 primary and 29 metastatic) into 3 groups according to their tertiles of SUV(max). We calculated recurrence odds ratios in the medium group and the high group compared to the low group using multivariate logistic analysis. After we examined the relationship between SUV(max) and recurrence in a crude model, we adjusted for some factors. Tumors with higher SUV(max) showed higher recurrence odds ratios (medium group; 1.84, high group; 4.14, respectively). The tumor size also increased the recurrence odds ratio (2.67); we thought this was mainly due to selection bias because we excluded tumors less than 10mm in diameter. This study demonstrated the pre-RFA SUV(max) in PET/CT may be a prognostic factor for local recurrence of malignant lung tumors.

F-18 FDG PET/CT contributes to more accurate detection of lymph nodal metastasis from actively proliferating esophageal squamous cell carcinoma.

PURPOSE: Evaluating the status of disease progression is critical for planning a therapeutic strategy for esophageal cancer. In this regard, F-18 fluorodeoxyglucose-labeled positron emission tomography (PET) is one of the most useful diagnostic modalities. However, there is room to improve its diagnostic performance, such as distinguishing lymph nodal metastases from false positives. In this study, we examined the diagnostic accuracy of fluorodeoxyglucose PET accompanied by computed tomography imaging (PET/CT) to detect regional lymph nodal metastasis from esophageal squamous cell carcinoma (ESCC). METHODS: A total of 102 patients diagnosed as ESCC were subjected to this study. These patients had a preoperative PET/CT examination to evaluate the existence of metastasis. The values of maximum standardized uptake value (SUVmax) in primary tumors and in metastasized lymph nodes were measured to analyze their relationship with various clinicopathologic characteristics including the status of tumor cell proliferation, which was assessed by immunohistochemistry for Ki-67. RESULTS: The SUVmax of the primary tumor was positively correlated with tumor size and vessel invasion, and was positively related with the SUVmax of lymph nodal metastasis, especially in cases of poorly differentiated ESCC. The SUVmax of metastasized lymph nodes was higher in larger-sized metastasized lymph nodes, whereas the Ki-labeling index of lymph nodal metastasis was positively related with the SUVmax per unit area (SUVmax/mm). The diagnostic accuracy of PET/CT (87.3%) was higher than that of conventional CT scans (78.4%). CONCLUSIONS: The improved diagnostic accuracy of PET/CT can be explained by its ability to detect actively progressive metastasis at an early phase regardless of size.

Reprint of: Simulation Platform: a cloud-based online simulation environment.

For multi-scale and multi-modal neural modeling, it is needed to handle multiple neural models described at different levels seamlessly. Database technology will become more important for these studies, specifically for downloading and handling the neural models seamlessly and effortlessly. To date, conventional neuroinformatics databases have solely been designed to archive model files, but the databases should provide a chance for users to validate the models before downloading them. In this paper, we report our on-going project to develop a cloud-based web service for online simulation called "Simulation Platform". Simulation Platform is a cloud of virtual machines running GNU/Linux. On a virtual machine, various software including developer tools such as compilers and libraries, popular neural simulators such as GENESIS, NEURON and NEST, and scientific software such as Gnuplot, R and Octave, are pre-installed. When a user posts a request, a virtual machine is assigned to the user, and the simulation starts on that machine. The user remotely accesses to the machine through a web browser and carries out the simulation, without the need to install any software but a web browser on the user's own computer. Therefore, Simulation Platform is expected to eliminate impediments to handle multiple neural models that require multiple software.

Preoperative graft volume assessment with 3D-CT volumetry in living-donor lobar lung transplantations.

To determine the effectiveness of living-donor lobar lung transplantation (LDLLT), it is necessary to predict the recipient's postoperative lung function. Traditionally, Date's formula, also called the segmental ratio, has used the number of lung segments to estimate the forced vital capacity (FVC) of grafts in LDLLT. To provide a more precise estimate of graft FVC, we calculated the volumes of the lower lobe and total lung using three-dimensional computed tomography (3D-CT) and the volume ratio between them. We calculated the volume ratio in 52 donors and tested the difference between the segmental volume ratios with a one-tailed t-test. We also calculated the predicted graft FVC in 21 LDLLTs using the segmental ratio pFVC(c) and the volume ratio pFVC(v), and then found the Pearson's correlation coefficients for both pFVC(c) and pFVC(v) with the recipients' actual FVC (rFVC) measured spirometrically 6 months after surgery. Significant differences were found between the segmental ratio and the average volume ratio for both sides (right, p＝0.03;left, p＝0.0003). Both pFVC(c) and pFVC(v) correlated significantly with rFVC at 6 months after surgery (p＝0.007 and 0.006). Both the conventional and the volumetric methods provided FVC predictions that correlated significantly with measured postoperative FVC.

Simulation Platform: a cloud-based online simulation environment.

For multi-scale and multi-modal neural modeling, it is needed to handle multiple neural models described at different levels seamlessly. Database technology will become more important for these studies, specifically for downloading and handling the neural models seamlessly and effortlessly. To date, conventional neuroinformatics databases have solely been designed to archive model files, but the databases should provide a chance for users to validate the models before downloading them. In this paper, we report our on-going project to develop a cloud-based web service for online simulation called "Simulation Platform". Simulation Platform is a cloud of virtual machines running GNU/Linux. On a virtual machine, various software including developer tools such as compilers and libraries, popular neural simulators such as GENESIS, NEURON and NEST, and scientific software such as Gnuplot, R and Octave, are pre-installed. When a user posts a request, a virtual machine is assigned to the user, and the simulation starts on that machine. The user remotely accesses to the machine through a web browser and carries out the simulation, without the need to install any software but a web browser on the user's own computer. Therefore, Simulation Platform is expected to eliminate impediments to handle multiple neural models that require multiple software.

The local efficacy of I-131 for F-18 FDG PET positive lesions in patients with recurrent or metastatic thyroid carcinomas.

PURPOSE: The aim of this study was to evaluate the local efficacy of I-131 for F-18 fluorodeoxyglucose positron emission tomography (FDG PET)-positive lesions. METHODS: Whole-body FDG PET/CT was performed on 37 patients (55 cases: 16 men, 21 women; age range: 24-82 years; mean age ± standard deviation: 60.5 ± 16.0 years) with differentiated thyroid cancer after total thyroidectomy. The metastatic or recurrent lesions were divided into 5 categories: primary tumor bed, lymph node, lung, bone, and other. The well-defined lesions were measured on CT, and the sizes were compared before and after radioactive iodine therapy. RESULTS: The analysis was performed on 37 patients with 44 lesions (lymph node:24, lung:16, bone:4). Sixteen lesions (70%) were increased and 7 (30%) showed no change or reduction when there was positive accumulation on FDG PET/CT and negative accumulation on I-131 (F(+)I(-)) group. In the positive accumulation for both FDG PET/CT and I-131 (F(+)I(+)) group, 5 lesions (63%) were increased and 3 (37%) showed no change or reduction. There was no significant difference for the tendency to increase in size between the F(+)I(-) and the F(+)I(+) groups. CONCLUSIONS: Lesions which show positive accumulations on FDG PET/CT have a greater tendency to increase in size. FDG-avid lesions are resistant to radioactive iodine therapy with or without I-131 uptake.

Interruption of the aortic arch: diagnosis with multidetector computed tomography.

PURPOSE: We investigated retrospectively the usefulness of multidetector computed tomography (MDCT) in the preoperative diagnosis of interruption of the aortic arch (IAA). MATERIALS AND METHODS: Seven neonates with IAA underwent enhanced MDCT before a surgical repair operation between April 2006 and March 2010. The MDCT procedures were performed using either a 16- or 64-MDCT scanner without electrocardiographic gating or respiratory arrest. RESULTS: High-quality CT images were obtained in all cases. One patient was diagnosed to be IAA type A, and 6 were diagnosed to be IAA type B (Celoria and Patton classification). The Celoria and Patton classification of IAA types and subtype classification by MDCT were confirmed by surgery. CONCLUSION: Our results show that the information from MDCT was sufficient for a preoperative diagnosis of IAA and allowed omission of a cardiac catheter examination before surgery.

The predictive value of measurement of SUVmax and SCC-antigen in patients with pretreatment of primary squamous cell carcinoma of cervix.

OBJECTIVE: Use of positron emission tomography/computed tomography (PET/CT) and serum squamous cell carcinoma (SCC) antigen (SCC-ag) as predictors for poor prognosis of pretreatment of primary SCC of cervix. METHODS: The distribution of cases that scored positive for each of the biological parameters examined was correlated with maximum SUV (SUVmax) of PET/CT and serum SCC-ag for 52 participants prior to radiotherapy (RT) with or without concurrent chemotherapy (CCRT) with pretreatment of primary SCC of cervix. RESULTS: There were significant correlations between the SUVmax of the primary tumor and tumor maximum size (P=0.027), and the lymph node metastasis (P=0.039). The serum SCC-ag had a statistically significant association with the clinicopathological parameters such as FIGO stage (P=0.045) and tumor maximum size (P=0.008), although there was no correlation noted between the SUVmax of the primary tumor and the serum SCC-ag (R=0.155). The high SUVmax of the primary tumor (≥ 15.6) plus lymph node metastasis (a short-axis diameter of over 10mm with a SUVmax ≥ 3.5) were significant predictors for poor prognosis when compared with the low SUVmax of the primary tumor (<15.6) or the high SUVmax of the primary tumor plus negative lymph node metastasis (a short-axis diameter of under 10mm or SUVmax <3.5) (overall survival rate; P=0.0211). CONCLUSIONS: The present findings indicate that the high SUVmax of the primary tumor plus lymph node metastasis with pretreatment of primary SCC of cervix may be associated with a poor prognosis.

The SUVmax of 18F-FDG PET correlates with histological grade in endometrial cancer.

OBJECTIVES: The objectives of this study were to assess the maximum standardized uptake value (SUVmax) of F-fluorodeoxyglucose (F-FDG) by a primary tumor of endometrial cancer with the use of positron emission tomography/computed tomography (PET/CT) and to assess its association with the clinical importance of the disease. METHODS: F-fluorodeoxyglucose PET/CT scan was performed on 44 participants within 2 weeks before surgery. F-fluorodeoxyglucose uptake was quantified by calculating the SUVmax. The distribution of cases that scored positive for each of the biological parameters examined was correlated with the SUVmax of the F-FDG PET/CT and the glucose transporter-1 expression status obtained by immunohistochemistry. RESULTS: The mean SUVmax of the primary endometrial cancer tumors was 17.6 (range, 3.04-34.74). There were significant correlations between the SUVmax of the primary tumor and the International Federation of Gynecology and Obstetrics (FIGO) grade (P < 0.001), maximum tumor size (P < 0.001), and glucose transporter-1 expression (P < 0.001). Furthermore, multivariate analysis showed that the FIGO grade was most significantly identified as a relation factor of SUVmax (> or =17.6) for endometrial cancer (P = 0.017). The present findings indicate that a significant relationship was seen between the SUVmax and the FIGO grade in endometrial cancer. CONCLUSION: We propose that the primary tumor's SUVmax obtained from F-FDG PET/CT may be associated with aggressive biological characteristics in endometrial cancer.

Positron emission tomography/computed tomography after immunocytochemical and clonal diagnosis of intraocular lymphoma with vitrectomy cell blocks.

The purpose of this study is to report the role of whole-body 2-[(18)F] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography fused with computed tomography (PET/CT) after immunocytochemical and clonal diagnosis of intraocular lymphoma with vitrectomy cell blocks. Eleven patients with intraocular lymphoma were involved in this study: 6 patients presented with vitreous opacity in both eyes and 5 patients presented with unilateral involvement. The concurrent retinal lesions were present in 6 eyes of 5 patients. Brain lymphoma was diagnosed in 7 of the 11 patients : simultaneous with eye lesions in one patient, following the eye lesions in 3, and prior to the eye lesions in 3. Vitrectomy was done in 17 eyes of the 11 patients, and vitrectomy cell blocks were processed for immunocytochemical staining and clonality analysis by polymerase chain reaction amplification of the immunoglobulin heavy chain gene. The 7 most recent patients were evaluated with fluorodeoxyglucose whole-body PET/CT. Immunocytochemical staining of vitrectomy cell blocks in all patients showed large cells which were positive for CD20 and Ki-67 but negative for CD3, consistent with diffuse large B-cell lymphoma. The size and sequence of amplified fragments of the immunoglobulin heavy chain gene were different between the lesions of both eyes in one patient while they were the same in another patient. PET/CT after the diagnosis by vitrectomy revealed abnormal uptake in the cerebellum of two patients, in the eye as a recurrent lesion of one patient, and in both eyes as residual retinal lesions of one patient. In conclusion, PET/CT could be considered as a method to confirm brain lymphoma or as a reference for initiating additional therapy in the case of eye recurrence or residual lesions after vitrectomy. The clonality of lymphoma cells was variable between the lesions in both eyes.

Dual-time-point F-18 FDG PET/CT for evaluation of intrathoracic lymph nodes in patients with non-small cell lung cancer.

PURPOSE: The aim of this study was to evaluate the diagnostic capacity of F-18 fluorodeoxyglucose dual-time-point (DTP) positron emission tomography (PET)/computed tomography (CT) for intrathoracic lymph node (LN) metastases in patients with nonsmall cell lung cancer (NSCLC). MATERIALS AND METHODS: Thirty-four patients had DTP PET/CT, with 60 minutes and 2-hour scans (n=19, NSCLC; n=15, benign pulmonary disease). LN diagnoses were confirmed by surgery or clinical follow-up (n=14, metastatic LNs; n=45, nonmetastatic LNs; n=39, inflammatory LNs). RESULTS: The maximum standardized uptake value (SUVmax) in the metastatic group was significantly higher than those in the nonmetastatic and inflammatory groups on both early- and delayed-phase imaging (each P<0.0001). The retention index (RI) of SUVmax (RI-SUVmax) in the metastatic group was significantly higher than in the nonmetastatic (P=0.0008) and inflammatory groups (P=0.0074). No significant difference was found between SUVmax values of the nonmetastatic and inflammatory groups on early- (P=0.6461) or delayed-phase (P=0.6913), or between RI-SUVmax values of the nonmetastatic and inflammatory groups (P=0.5717). For early-phase SUVmax, the cut-off value for highest accuracy with metastatic LNs was 3.61, yielding a sensitivity of 86.67% and a specificity of 88.00%. For delayed-phase SUVmax, the cut-off value was 4.00, yielding a sensitivity of 91.6% and specificity of 92.9%. For RI-SUVmax, the cut-off value was 20.91%, yielding a sensitivity of 73.6% and specificity of 75.9%. CONCLUSIONS: DTP PET/CT with a semiquantitative technique may improve diagnostic capacity for nodal staging of NSCLC.

Preliminary retrospective investigation of FDG-PET/CT timing in follow-up of ablated lung tumor.

OBJECTIVE: The aim of this study was to clarify the most appropriate follow-up initiation time point for positron emission tomography (PET)/computed tomography (CT) following radio frequency ablation (RFA) of lung tumors, and the cutoff values of maximum standard uptake value (SUV(max)) to evaluate local tumor progression. METHODS: We enrolled 15 patients (8 men, median age 62 years) with 60 tumors, who were treated with RFA of lung tumors and underwent fluorodeoxyglucose (FDG)-PET/CT following RFA. Local tumor progression was assessed by periodic chest CT images prior to and following intravenous administration of a contrast medium. The SUV(max) of three periods, namely, 0-3 months, 3-6 months, and 6-9 months after RFA, was evaluated. The appropriate time point for follow-up initiation and the cutoff value of SUV(max) were determined using receiver-operating characteristic (ROC) analysis. RESULTS: The median follow-up period was 357 days. Of 60 tumors, 10 showed local progression. The area under the ROC curve (Az) for the 6-9 months (P = 0.044) was the largest and almost equal to that of the 3-6 months (P = 0.024). Az for the 0-3 months was the smallest and statistically insignificant (P = 0.705). The cutoff value of 1.5 of SUV(max) at 3-9 months after RFA showed 77.8% sensitivity and 85.7-90.5% specificity. CONCLUSIONS: The appropriate follow-up initiation time point is at least 3 months following RFA. Thus, SUV(max) is a useful and reliable predictive indicator.

Inter-observer variations in FDG-PET interpretation for cancer screening.

BACKGROUND: Diagnostic guidelines for the use of 2-(fluorine 18) fluoro-2 deoxy-D-glucose (FDG)-positron emission tomography (PET) in cancer screening have yet to be established. We assessed inter-observer variability in screening FDG-PET. METHODS: Subjects comprised 40 individuals who underwent FDG-PET and computed tomography (CT) for cancer screening. To assess various patterns of FDG uptakes, three subsets of the cases were selected: 'Cancer', 15 cases with cancer; 'Not malignant', 15 cases with suspected cancer by FDG-PET who were confirmed as cancer-free; and 'Normal', 10 cases without remarkable FDG uptake who were confirmed as cancer-free. A total of 68 lesions made up of malignancy (n = 18), benign (n = 21), and physiological FDG uptake (n = 29) were interpreted by six physicians. Each observer reviewed each case three times. Step 1 involved interpretation of PET images alone, Step 2 involved side-by-side reading of PET and CT images, and Step 3 involved re-evaluation of findings with the results of other screening tests. We assessed inter-observer agreement for each step. RESULTS: Inter-observer agreement for all lesions at each step was moderate, compared to fair agreement for 'Normal' subjects. Inter-observer agreement of 'Cancer' and 'Not malignant' subjects in Step 1 were better than those in Step 2 and 3; however, the differences were not statistically significant. CONCLUSION: The interpretation of FDG-PET is adequately reproducible, while that of 'Normal' subjects is less reproducible. Improvement of inter-observer variability in assessing physiological FDG uptakes requires universal reporting criteria in FDG-PET. Correlative interpretation of PET, CT and other information may require standardization in subjects with suspected cancer by FDG-PET.