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Purpose: F-FP-CIT [F-fluorinated N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) nortropane] has been well established and used for the differential diagnosis of atypical parkinsonian disorders. Recently, combined positron emission tomography (PET)/magnetic resonance (MR) was proposed as a viable alternative to PET/computed tomography (CT). The aim of this study was to compare the performances of conventional F-FP-CIT brain PET/CT and simultaneous PET/MR by visual inspection and quantitative analysis. Methods: Fifteen consecutive patients clinically suspected of having Parkinson's disease were recruited for the study.F-FP-CIT PET was performed during PET/CT and PET/MR. PET/CT image acquisition was started 90 min after intravenous injection of F-FP-CIT and then PET/MR images were acquired. Dopamine transporter (DAT) density in bilateral striatal subregions was assessed visually. Quantitative analyses were performed on bilateral striatal volumes of interest (VOIs) using average standardized uptake values (SUVmeans). Intraclass correlation coefficients (ICCs) and their 95 % confidence intervals (CIs) were assessed to compare PET/CT and PET/MR data. Bland-Altman plots were drawn to perform method-comparisons. Results: All subjects showed a preferential decrease in DAT binding in the posterior putamen (PP), with relative sparing of the ventral putamen (VP). Bilateral striatal subregional binding ratio (BR) determined PET/CT and PET/MR demonstrated close interequipment correspondence (BR - ICC, 0.944; 95 % CI, 0.835-0.981, BR - ICC, 0.917; 95 % CI, 0.753-0.972, BR - ICC, 0.976; 95 % CI, 0.929-0.992 and BR - ICC, 0.970; 95 % CI, 0.911-0.990, respectively), and Bland-Altman plots showed interequipment agreement between the two modalities. Conclusions: It is known that MR provides more information about anatomical changes associated with brain diseases and to enable the anatomical allocations of subregions than CT, though this was not observed in the present study. Although the subregional BR of simultaneous PET/MR was comparable to that of PET/CT in Parkinson's disease, our isocontouring method could make bias. A future automated method using standard template study or manual segmentation of putamen/caudate based on MR or CT is needed. [ABSTRACT FROM AUTHOR]

Purpose: In a whole-body 18F-FDG PET/CT, non-specific 18F-FDG uptake of the myocardium is a common finding and can be very variable, ranging from background activity to intense accumulation and inhomogeneity. We investigated the effect of energy substrates and plasma/serum hormones that may have an influence on myocardial 18F-FDG uptake. Methods: F-FDG PET/CT was performed on 100 normal volunteers from November 2007 to August 2008. Blood samples were taken just before 18F-FDG injection from all subjects. Myocardial 18F-FDG uptake was measured as the mean (SUVmean) and maximal (SUVmax) standardized uptake value. The myocardium was delineated on the PET/CT image by a manual volume of interest (VOI). We analyzed the influence of age, sex, presence of diabetes, fasting duration, insulin, glucagon, fasting glucose, lactate, free fatty acid (FFA), epinephrine (EPi), norepinephrine (NEp), free triiodothyronine (T3), free thyroxine (T4), thyroid-stimulating hormone (TSH) and body mass index (BMI). Results: Overall, 92 subjects (mean age 50.28 ± 8.30, male 57) were enrolled. The average of myocardial SUVmean was 2.08 and of myocardial SUVmax was 4.57, respectively and there was a strong linear correlation between SUVmean and SUVmax ( r = 0.98). FFA and fasting duration showed significant negative correlation with myocardial 18F-FDG uptake, respectively ( r = −0.40 in FFA; r = −0.41 in fasting duration). No significant relationships were observed between myocardial uptake and age, sex, presence of diabetics, insulin, glucagon, fasting glucose, lactate, EPi, NEp, free T3, free T4, TSH and BMI. Conclusion: Myocardial 18F-FDG uptake decreases with longer fasting duration and higher FFA level in normal humans. Modulating myocardial uptake could improve 18F-FDG PET/CT imaging for specific oncologic and cardiovascular indications. [ABSTRACT FROM AUTHOR]

Purpose: There is still no definite method to determine therapeutic response in pyogenic vertebral osteomyelitis (PVO). We analyzed the value of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for assessing therapeutic response in PVO. Methods: This retrospective study included 53 patients (32 men and 21 women) with lumbar PVO. The results of clinical assessments for therapeutic response were divided into "Cured" (group C) and "Non-cured" (group NC). The differences in clinical and radiological features of PVO lesions between the two groups were analyzed using clinical data and simultaneous FDG-PET/magnetic resonance imaging (MRI) obtained at each clinical assessment. Results: Clinical assessments and FDG-PET/MRIs were performed at 41.89 ± 16.08 (21–91) days of parenteral antibiotic therapy. There were 39 patients in group C and 14 in group NC. Diagnostic accuracies (DAs) of FDG uptake intensity-based interpretation and C-reactive protein (CRP) for residual PVO were as follows (p < 0.01): 84.9% of the maximum standardized uptake value of PVO lesion (PvoSUVmax), 86.8% of ΔPvoSUVmax−NmlSUVmax (SUVmax of normal vertebra), 86.8% of ΔPvoSUVmax−NmlSUVmean (SUVmean of normal vertebra), and 71.7% of CRP. DAs were better (92.5–94.3%) when applying FDG uptake intensity-based interpretation and CRP together. Under the FDG uptake distribution-based interpretation, FDG uptake was significantly limited to intervertebral structures in group C (p = 0.026). Conclusion: The interpretations of intensity and distribution of FDG uptake on FDG-PET are useful for detecting residual PVO in the assessment of therapeutic response of PVO. The combination of FDG-PET and CRP is expected to increase DA for detecting residual PVO. [ABSTRACT FROM AUTHOR]

Background and Objectives: This study investigated the usefulness of deep neural network (DNN) models based on 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) and blood inflammatory markers to assess the therapeutic response in pyogenic vertebral osteomyelitis (PVO). Materials and Methods: This was a retrospective study with prospectively collected data. Seventy-four patients diagnosed with PVO underwent clinical assessment for therapeutic responses based on clinical features during antibiotic therapy. The decisions of the clinical assessment were confirmed as 'Cured' or 'Non-cured'. FDG-PETs were conducted concomitantly regardless of the decision at each clinical assessment. We developed DNN models depending on the use of attributes, including C-reactive protein (CRP), erythrocyte sedimentation ratio (ESR), and maximum standardized FDG uptake values of PVO lesions (SUV max ), and we compared their performances to predict PVO remission. Results: The 126 decisions (80 'Cured' and 46 'Non-cured' patients) were randomly assigned with training and test sets (7:3). We trained DNN models using a training set and evaluated their performances for a test set. DNN model 1 had an accuracy of 76.3% and an area under the receiver operating characteristic curve (AUC) of 0.768 [95% confidence interval, 0.625-0.910] using CRP and ESR, and these values were 79% and 0.804 [0.674-0.933] for DNN model 2 using ESR and SUV max , 86.8% and 0.851 [0.726-0.976] for DNN model 3 using CRP and SUV max , and 89.5% and 0.902 [0.804-0.999] for DNN model 4 using ESR, CRP, and SUV max , respectively. Conclusions: The DNN models using SUV max showed better performances when predicting the remission of PVO compared to CRP and ESR. The best performance was obtained in the DNN model using all attributes, including CRP, ESR, and SUV max , which may be helpful for predicting the accurate remission of PVO.

Background and objectives: The clinical assessment of therapeutic response in pyogenic vertebral osteomyelitis (PVO) has been usually performed based on the changes of clinical symptoms and blood inflammatory markers. Recently, 18 F-fluorodeoxyglucose positron emission tomography ( 18 F-FDG-PET) has emerged as an alternative independent method. We analyzed the validity of the clinical assessment for detecting residual PVO based on 18 F-FDG-PET. Materials and Methods: This study was conducted with 53 patients confirmed as lumbar PVO under retrospective design. All patients underwent clinical assessment using clinical symptoms and C-reactive protein (CRP) for therapeutic response after parenteral antibiotic therapy, which led to the decision of placement in the uncontrolled (group UC) or controlled (group C) group. The validity of clinical assessment was analyzed based on the cut-off values of FDG uptake for detecting residual PVO as references, which are already established in the previous literature. Results : The mean duration of parenteral antibiotic therapy and recurrence rate were 42.19 ± 15.84 (21-89) days and 9.4% (5/53), respectively. 18 F-FDG-PETs were performed at 80 rounds of clinical assessment on 37.40 ± 13.15 (21-83) days of parenteral antibiotic therapy and divided: 31 into group UC and 49 into group C, according to the decisions of clinical assessment. Based on the cut-off values of FDG uptake, clinical assessment showed 48.4-58.1% of false positive for residual PVO in group UC. However, 18 F-FDG-PET showed 8.2% (4/49) of false negative for residual PVO in group C, which led to recurrences. Conclusions: Clinical assessment using clinical symptoms and CRP for evaluating therapeutic response in PVO is still a useful method in terms of similar recurrence rate compared to 18 F-FDG-PET. However, the high rate of false positive for residual PVO can prolong the use of unnecessary antibiotics and overall treatment period.

This study aimed to develop a prognosis-predicting model based on [ 18 F]fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) and clinicopathologic factors in locally advanced cervical cancer patients treated with concurrent chemoradiotherapy (CCRT). The medical records of 270 locally advanced cervical cancer patients who were treated with CCRT were collected from three institutions and reviewed retrospectively. A nomogram was used for predicting 2-year disease-free survival (DFS) and 5-year overall survival (OS) based on Cox proportional hazards regression. Predictor variables included nodal maximum standardized uptake value (SUVmax), primary tumor SUVmax, age, tumor size, stage, serum squamous cell carcinoma antigen level, and human papillomavirus status. Internal nomogram validation was performed. A nomogram for predicting the 2-year DFS and 5-year OS was constructed using six and seven parameters, respectively. With a focus on 2-year DFS, our model found nodal SUVmax to be the highest weighted negative prognostic factor. With a focus on 5-year OS, young age was the highest weighted negative prognostic factor. The concordance index was 0.75 and 0.78 for the 2-year DFS and 5-year OS, respectively. This nomogram is a predictive tool that can be used to counsel patients for predicting survival outcomes. Moreover, our prognosis-predicting model may make it possible to personalize treatment.

Objective: The Dixon sequence is acquired for attenuation correction (AC) of positron emission tomography (PET) data in integrated PET/magnetic resonance (MR). However it sometimes misclassifies soft tissue and fat in μ-map. In the present study, we investigated factors related to this misclassification and their clinical impacts., Subject and Methods: Forty-eight oncological patients (19 males and 29 females, mean age: 59±11 years old) underwent a single fluorine-18 fluorodeoxyglucose ((18)F-FDG) injection/dualimaging protocol on PET/computed tomography (CT) and subsequently PET/MR. Patients were assigned to either of two groups; group A with a misclassification in at least one bed position or group B with a correctly classified μ-map. We compared body mass index (BMI), lean body mass, fasting duration, volume of hydration and age between group A and group B. In addition, we analyzed the impact of PET quantification using standard uptake ratio (SUR) defined as uptake in volume of interest/uptake in thigh muscle. The Dixon-AC SUR was compared with CT-AC SUR in misclassified bed positions and correctly classified bed positions. All patients were scanned in four bed positions by PET/MR. Ten patients were assigned to group A; six showed misclassification in a bed position (5 in head and 1 in abdomen), three patients in 3 bed positions (head-thorax-abdomen), and one patient in partial bed position in neck., Results: Misclassification was observed in 21% of 48 patients. Group A and group B showed no statistically significant differences in BMI, lean body mass, fasting duration or age, however the volume of hydration in group A (245mL) was smaller than in group B (452.6mL) (P=0.027). In group A, we analyzed Dixon-AC SUR/CT-AC SUR ratios in 16 misclassified and 24 correctly classified regions, and ratios in these regions were significant different 0.80 and 0.93, respectively (P=0.046)., Conclusion: Because no corrective method has been devised after a scan, we recommend that Dixon images with μ-maps should be checked before interpreting PET/MR images and emphasize the importance of hydration, pre-examination. Misclassification errors do not change the presence of (18)F-FDG uptake but can have significant impacts on PET quantification in affected bed positions.