Minimum Standardized Uptake Values Research Articles

A [18F]FDG PET based nomogram to predict cancer-associated cachexia and survival outcome: A multi-center study

ObjectivesCancer patients with cachexia face poor prognosis and shortened survival. Early diagnosis and accurate prognosis prediction remain challenging. This multi-center study aims to develop and externally validate a nomogram integrating [18F]fluoro-2-deoxy-D-glucose ([18F]FDG) PET findings and routine clinical biochemistry tests for predicting cancer-associated cachexia, while also assessing its potential prognostic value. Research Methods & ProceduresA retrospective analysis of 658 cancer patients (390 in the development cohort, 268 in the validation cohort) utilized [18F]FDG PET/CT data from two centers. Logistic regression identified organ-specific standardized uptake values (SUVs) and clinical variables associated with cancer-associated cachexia. Diagnostic accuracy, discriminative ability, and clinical effectiveness were assessed using area under the curve (AUC), calibration curve, and decision curve. Nomogram predictability for overall survival was evaluated through Cox regression and Kaplan–Meier curves. ResultsThe combined nomogram incorporating age (odds ratio [OR] = 1.893; P = 0.012), hemoglobin (OR = 2.591; P < 0.001), maximum SUV of the liver (OR = 3.646; P < 0.001), and minimum SUV of the subcutaneous fat (OR = 5.060; P < 0.001) achieved good performance in predicting cancer-associated cachexia (AUC = 0.807/0.726, development/validation). Calibration and decision curve analyses confirmed its clinical effectiveness. Kaplan–Meier curves analysis showed that overall survival can be categorized using the combined nomogram (P < 0.001). ConclusionCombining radiological information from clinical standard [18F]FDG PET data from cancer patients with biochemical results in their routine clinical blood tests through a well-constructed nomogram enables predicting cachexia and its effect on the prognosis of cancer patients.

Predictive Value of Quantitative Parameters of 18F-FDG PET/CT in Patients with Liposarcoma.

The purpose of this study was to evaluate the predictive features of baseline F-18-fluorodeoxy-D-glucose positron emission tomography (18F-FDG PET)/computed tomography (CT) parameters in patients with dedifferentiated liposarcomas (DDLPSs) and well-differentiated liposarcomas (WDLPSs) receiving systemic treatment. A total of 24 patients with liposarcoma who underwent longitudinal 18F-FDG PET/CT in systemic therapy were included. All volumetric segmentation of each tumor section and semiquantitative imaging parameters were extracted from the axial field of view from both PET and CT images. Maximum, mean, and minimum standardized uptake values (SUVmax, SUVmean, and SUVmin), Hounsfield units (HUs), and their respective changes from baseline and posttreatment were calculated. The voxel values from unenhanced CT images were correlated with PET-derived parameters. The 18F-FDG uptake decreased by more than 56% on average in responders for both SUVmax and SUVmean in DDLPS. There was a decrease in HUmax in DDLPS among responders. Using AUC > 0.8 as a reasonable predictor, we found that the ratios of SUVmaxD/HUmean, SUVmaxD/HUmedian, and SUVmeanD/HUmedian at baseline were significant indicators of the response to treatment in patients with liposarcoma. The changes in SUVmean and not just SUVmax parameters could be considered as accurate tumor response indicators. For the first time, we introduced baseline SUV/HU ratios as a valuable diagnostic tool in predicting liposarcoma treatment outcomes. This ability was not revealed by classic semiquantitative PET or CT parameters at baseline.

Correlation between L-amino acid transporter 1 expression and 4-borono-2-18 F-fluoro-phenylalanine accumulation in humans.

The correlation between L-type amino acid transporter 1 (LAT1) expression and 4-borono-2-18 F-fluoro-phenylalanine (18 F-FBPA) accumulation in humans remains unclear. This study aimed to investigate the correlation between LAT1 expression in tumor tissues and 18 F-FBPA accumulation in patients with head and neck cancer who participated in a clinical trial of 18 F-FBPA positron emission tomography (PET). Altogether, 28 patients with head and neck cancer who participated in a clinical trial of 18 F-FBPA PET at our institution between March 2012 and January 2018 were included. Correlations between standardized uptake values (SUVs); the maximum SUV (SUVmax ), the mean SUV within a 1 cm3 sphere centered at a single point, that is, the SUVmax (SUVpeak ), the minimum SUV (SUVmin ), and the intensity of LAT1 expression (maximum and minimum LAT1 expressions) were investigated. Weak correlations were identified between SUVmax and LAT1 maximum score, SUVmin and LAT1 maximum score, and SUVmin and LAT1 minimum score (ρ = 0.427, 0.362, and 0.330, respectively). SUVmax and LAT1 minimum score, SUVpeak and LAT1 maximum score, and SUVpeak and LAT1 minimum score demonstrated moderate correlations (ρ = 0.535, 0.556, and 0.661, respectively). Boron neutron capture therapy (BNCT) was performed in 2 of the 4 patients with discrepancies between 18 F-FBPA accumulation and intensity of LAT1 expression, and the intensity of LAT1 expression was a better predictor of treatment response. 18 F-FBPA accumulation and the intensity of LAT1 expression demonstrated a moderate correlation; however, LAT1 expression may be a better predictor of treatment response of BNCT in patients with discrepancies.

Radiomic signatures based on pretreatment 18F-FDG PET/CT, combined with clinicopathological characteristics, as early prognostic biomarkers among patients with invasive breast cancer.

The aim of this study was to investigate the predictive role of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the prognostic risk stratification of patients with invasive breast cancer (IBC). To achieve this, we developed a clinicopathologic-radiomic-based model (C-R model) and established a nomogram that could be utilized in clinical practice. We retrospectively enrolled a total of 91 patients who underwent preoperative 18F-FDG PET/CT and randomly divided them into training (n=63) and testing cohorts (n=28). Radiomic signatures (RSs) were identified using the least absolute shrinkage and selection operator (LASSO) regression algorithm and used to compute the radiomic score (Rad-score). Patients were assigned to high- and low-risk groups based on the optimal cut-off value of the receiver operating characteristic (ROC) curve analysis for both Rad-score and clinicopathological risk factors. Univariate and multivariate Cox regression analyses were performed to determine the association between these variables and progression-free survival (PFS) or overall survival (OS). We then plotted a nomogram integrating all these factors to validate the predictive performance of survival status. The Rad-score, age, clinical M stage, and minimum standardized uptake value (SUVmin) were identified as independent prognostic factors for predicting PFS, while only Rad-score, age, and clinical M stage were found to be prognostic factors for OS in the training cohort. In the testing cohort, the C-R model showed superior performance compared to single clinical or radiomic models. The concordance index (C-index) values for the C-R model, clinical model, and radiomic model were 0.816, 0.772, and 0.647 for predicting PFS, and 0.882, 0.824, and 0.754 for OS, respectively. Furthermore, decision curve analysis (DCA) and calibration curves demonstrated that the C-R model had a good ability for both clinical net benefit and application. The combination of clinicopathological risks and baseline PET/CT-derived Rad-score could be used to evaluate the prognosis in patients with IBC. The predictive nomogram based on the C-R model further enhanced individualized estimation and allowed for more accurate prediction of patient outcomes.

Could Maximum SUV be Used as Imaging Guidance in Large Lung Lesions Biopsies? Double Sampling Under PET-CT/XperGuide Fusion Imaging in Inhomogeneous Lung Uptaking Lesions to Show That it can Make a Difference.

Introduction: The purpose of this study is to evaluate the diagnostic value of positron emission computed tomography-cone beam computed tomography (PET/CT-CBCT) fusion guided percutaneous biopsy, targeted to the maximum standardized uptake value (SUVmax) and minimum standardized uptake value (SUVmin) of large lung lesions. Materials and Methods: Inside a larger cohort of PET/CT-CBCT guided percutaneous lung biopsies, 10 patients with large pulmonary lesions (diameter > 30 mm) were selected retrospectively. These patients have been subjected to double biopsy sampling respectively in the SUVmax area and in the SUVmin area of the lesion. Technical success has been calculated. For each sample, the percentage of neoplastic, inflammatory, and fibrotic cells was reported. Furthermore, the possibility of performing immunohistochemical or molecular biology investigations to specifically define the biomolecular tumor profile was analyzed. Results: Nine lesions were found to be malignant, one benign (inflammation). Technical success was 100% (10/10) in the SUVmax samples and 70% (7/10) in the SUVmin samples (P-value: .21). In the first group, higher percentages of neoplastic cells were found at pathologic evaluation, while in the second group areas of inflammation and fibrosis were more represented. The biomolecular profile was obtained in 100% of cases (9/9) of the first group, while in the second group only in 33.3% of cases (2/6), with a statistically significant difference between the 2 groups (P-value: .011). Conclusion: A correlation between the standardized uptake value value and the technical success of the biopsy sample has been identified. PET/CT-CBCT guidance allows to target the biopsy in the areas of the tumor which are richer in neoplastic cells, thus obtaining more useful information for the planning of patient-tailored cancer treatments.

Abnormal [18F]FDG uptake in liver and adipose tissue: a potential imaging biomarker for cancer-associated cachexia.

This study aims to investigate and develop imaging biomarkers for the diagnosis of cancer-associated cachexia based on the organ and tissue-specific abnormal metabolisms measured by fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT. FDG PET/CT data from 390 cancer patients were analyzed retrospectively. Patients were divided into a development cohort and a validation cohort. Cachexia was defined as weight loss > 5% in 6 months or BMI < 20 and weight loss > 2%. According to the above definitions, patients were divided into cachexia and non-cachexia groups. Results of the clinical laboratory tests for metabolic levels and organ and tissue-specific FDG uptake obtained from the cachexia and non-cachexia groups were compared statistically. Logistic regression analysis was performed to identify independent variables associated with cachexia in the development cohort for generating the regression model. The performance of the model was tested using the data from a validation cohort and evaluated by area under the receiver operating characteristic curve (AUC). Based on the data from the development cohort of 286 patients and a validation cohort of 104 patients, it is found that age, white blood cell count, peak standardized uptake value (SUV) of the liver, and minimum SUV of lean body mass of visceral fat and subcutaneous fat were independently associated with cachexia. The model incorporating these variables reached an AUC of 0.777 (95% confidence interval (CI): 0.721, 0.833) in the development cohort and an AUC of 0.729 (95% CI: 0.629, 0.829) in the validation cohort. Organ and tissue-specific abnormal glucose metabolism as measured by PET/CT can be used as a biomarker for cancer-associated cachexia. • Patients with cancer-associated cachexia have reduced FDG uptake in the liver and increased FDG uptake in visceral fat and subcutaneous fat. • FDG uptake of the liver, visceral fat, and subcutaneous fat can be independent risk factors for identifying cancer-associated cachexia. • Cancer-associated cachexia can be classified using the model that incorporates age, white blood cell count, FDG uptake of the liver, and visceral and subcutaneous fat can diagnose with an AUC of 0.729.

Prognostic Value of Axillary Lymph Node Texture Parameters Measured by Pretreatment 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Locally Advanced Breast Cancer with Neoadjuvant Chemotherapy.

Background: This study investigated the prognostic value of axillary lymph node (ALN) heterogeneity texture features through 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with locally advanced breast cancer (LABC). Methods: We retrospectively analyzed 158 LABC patients with FDG-avid, pathology-proven, metastatic ALN who underwent neoadjuvant chemotherapy (NAC) and curative surgery. Tumor and ALN texture parameters were extracted from pretreatment 18F-FDG PET/CT using Chang-Gung Image Texture Analysis software. The least absolute shrinkage and selection operator regression was performed to select the most significant predictive texture parameters. The predictive impact of texture parameters was evaluated for both progression-free survival and pathologic NAC response. Results: The median follow-up period of 36.8 months and progression of disease (PD) was observed in 36 patients. In the univariate analysis, ALN textures (minimum standardized uptake value (SUV) (p = 0.026), SUV skewness (p = 0.038), SUV bias-corrected Kurtosis (p = 0.034), total lesion glycolysis (p = 0.011)), tumor textures (low-intensity size zone emphasis (p = 0.045), minimum SUV (p = 0.047), and homogeneity (p = 0.041)) were significant texture predictors. On the Cox regression analysis, ALN SUV skewness was an independent texture predictor of PD (p = 0.016, hazard ratio 2.3, 95% confidence interval 1.16–4.58). Conclusions: ALN texture feature from pretreatment 18F-FDG PET/CT is useful for the prediction of LABC progression.

S-methyl-11C]-L-methionine positron emission tomography/computed tomography imaging parameters to evaluate early response for esophageal cancer with neoadjuvant carbon ion radiotherapy

This study aimed to evaluate the uptake of the clinical effectiveness of [S-methyl-11C]-L-methionine positron emission tomography/computed tomography (MET PET/CT) in patients with esophageal cancer and to investigate MET PET/CT imaging parameters to assess early response for esophageal cancer with neoadjuvant carbon ion radiotherapy (CIRT). MET PET/CT scans were performed in nineteen patients before and 3 weeks after completion of CIRT. After Surgery, the effect of neoadjuvant CIRT was investigated by examining the relationship between each parameter of MET uptake and the histological assessment (grade and tumor residual ratio). Four parameters of MET uptake were the maximum and minimum standardized uptake values of pre and post CIRT (pre-SUVmax, pre-SUVmean, post-SUVmax, and post-SUVmean). MET PET/CT imaging of esophageal cancer was clearly demonstrated. The post-SUVmax was the most suitable parameter. When the cutoff value was set as post-SUVmax = 6.21, the sensitivity, the specificity, and the accuracy of Grades 3 were 100.0%, 63.6%, and 78.9%, respectively. And there was a positive relationship between the tumor residual ratio and post-SUVmax (R2 = 0.38, p < 0.005). MET PET/CT is clinically useful for the assessment of early response to neoadjuvant CIRT in esophageal cancer. Particularly, post-SUVmax is considered a promising PET imaging parameter.

Positive-pressure breath-hold positron emission tomography/computed tomography is feasible for respiratory-induced artifact reduction in healthy dogs.

To perform qualitative and quantitative analysis of positron emission tomography (PET)/CT images using spontaneous ventilation (SV) and positive-pressure breath-hold (PPBH) techniques in order to demonstrate the feasibility of PPBH PET/CT to decrease respiration-induced artifacts. 5 healthy female mixed-breed dogs. 2-([18F]fluoro)-2-deoxy-D-glucose (was administered to each anesthetized dog. An SV PET/CT scan was performed from the head to the femur using 8 bed positions (3 min/bed) followed by a PPBH scan centered over the diaphragm with a single bed position (1.5 min/bed). PET image quality, the misalignment of organs between PET and CT images, and standardized uptake values (SUVs) of liver adjacent to diaphragm were compared between SV and PPBH. Overall image quality and conspicuity of anatomic structures were superior in PPBH than in SV PET images. PPBH induced significantly less misalignment of the liver and diaphragm in all planes compared to SV. For the gall bladder, PPBH showed significantly less misalignment than SV only in the transverse plane. The maximum SUV in all of the liver areas was significantly higher with PPBH compared to SV. PPBH exhibited significantly higher mean SUV in the liver adjacent to the left diaphragmatic dome and left lateral border and higher minimum SUV only in the liver adjacent to the left diaphragmatic dome. PPBH was demonstrated to be a feasible PET/CT protocol with higher PET image quality, less organ misalignment on fused PET/CT, and more accurate SUVs of the liver compared to SV PET/CT in healthy dogs.

Quantitative 99mTc-MDP SPECT/CT as an alternative to 18F-NaF PET/CT for objective assessment of osteoblastic bone metastases.

To investigate the correlation between the standardized uptake value (SUV) metrics derived from technetium-99m (99mTc) methylene diphosphonate (MDP) single photon emission computed tomography/computed tomography (SPECT/CT) and fluorine-18 (18F) sodium fluoride (NaF) positron emission tomography (PET)/CT. A total of 129 metastatic lesions from 14 patients who underwent both 99mTc-MDP SPECT/CT and 18F-NaF PET/CT within one month were included in the analyses. The lesions with markedly increased uptake were semi-automatically segmented into a volume of interest in both SPECT and PET images by taking the 42% of maximum uptake as a threshold. Maximum, average and minimum SUV (namely, SUVmax, SUVmean and SUVmin) were recorded for each lesion. The strength of correlation was evaluated with Pearson's correlation analysis. The correlation coefficitients for SUVmax, SUVmean and SUVmin derived SPECT and PET images were 0.652, 0.653 and 0.635, respectively (all P<0.001). Lesions with a volume of at least 5cm3 demonstrated a stronger correlation, increasing the correlation coefficients to 0.714, 0.724 and 0.686, respectively (all P<0.001). The strongest correlation was seen in the lesions of the appendicular skeleton, with coefficients for SUVmax, SUVmean and SUVmin being 0.769, 0.791 and 0.761, respectively (all P<0.001). The SUV metrics derived from 99mTc-MDP SPECT/CT strongly correlate with 18F-NaF PET, especially for relatively large lesions located in the appendicular skeleton. Technetium-99m-MDP SPECT/CT could potentially be used as an alternative method to 18F-NaF PET/CT for quantitative evaluation and objective follow-up of bone metastases.

Usefulness of Bone SPECT/CT for Predicting Avascular Necrosis of the Femoral Head in Children with Slipped Capital Femoral Epiphysis or Femoral Neck Fracture.

ObjectiveThis study aimed to investigate the usefulness of bone single-positron emission tomography/computed tomography (SPECT/CT) of the hip in predicting the later occurrence of avascular necrosis (AVN) after slipped capital femoral epiphysis (SCFE) or femoral neck fracture in pediatric patients. The quantitative parameters of SPECT/CT useful in predicting AVN were identified.Materials and MethodsTwenty-one (male:female, 10:11) consecutive patients aged < 18 years (mean age ± standard deviation [SD], 11.0 ± 2.7 years) who underwent surgery for SCFE or femoral neck fracture and postoperative bone SPECT/CT were included. The maximum standardized uptake value (SUV), mean SUV, and minimum SUV of the femoral head were measured. The ratios of the maximum SUV, mean SUV, and minimum SUV of the affected femoral head to the contralateral side were determined. Patients were followed up for > 1 year after the surgery. The SPECT/CT parameters were compared between patients who developed AVN and those who did not. The accuracy of SPECT/CT parameters for predicting AVN was assessed.ResultsSix patients developed AVN. There was a significant difference in the ratio of the mean SUV among patients who developed AVN (mean ± SD, 0.8 ± 0.3) and those who did not (1.1 ± 0.2, p = 0.018). However, there were no significant differences in the ratios of the maximum and minimum SUV between the groups (all p = 0.205). For the maximum, mean, and minimum SUVs, no significant differences were observed between the groups (p = 0.519, 0.733, and 0.470, respectively). The cutoff mean SUV ratio of 0.87 yielded a 66.7% sensitivity and 93.2% specificity for predicting AVN.ConclusionQuantitative bone SPECT/CT is useful for evaluating femoral head viability in pediatric patients with SCFE or femoral neck fractures. Clinicians should consider the high possibility of later AVN development in patients with a decreased mean SUV ratio.

18F-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography With Magnetic Resonance for Diagnosing Adult-Onset Still's Disease.

Objective: The objective of the study was to assess the advantages of 18F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography with magnetic resonance (PET/CT-MR) in diagnosing and monitoring patients with adult-onset Still's disease (AOSD).Methods: Participants in this retrospective case-control study underwent whole-body 18F-FDG-PET/CT-MR imaging. All PET scans were qualitatively and semiquantitatively analyzed using standardized uptake values (SUVs) normalized to liver uptake, i.e., we calculated the ratio (SUVr) between the minimum, maximum, and mean SUVs for different organs and tissues and the mean SUV for the liver. Disease activity scores were assessed using Pouchot's criteria.Results: Eighteen patients diagnosed with AOSD and 24 controls (non-AOSD patients diagnosed with solid tumors, excluding lymphomas) were considered. A total of 38 PET/MR and nine PET/CT scans were analyzed. AOSD patients had higher SUVr than controls. All SUVr differed significantly between the patient and control group for bone marrow, and for the spleen, the only difference lacking statistical significance concerned the ratio of the minimum SUV for spleen to the mean SUV for liver. Though limited in number, AOSD responders to therapy showed lower uptakes during the period monitored. No correlations were found between Pouchot's scores and SUVr.Conclusion: Our data revealed higher spleen and bone marrow 18F-FDG uptakes on PET/CT and PET/MR images in AOSD patients than in controls. Together with clinical examinations and laboratory data, PET/CT and PET/MR seemed more reliable than Pouchot's score in assessing disease activity.

Machine learning-based FDG PET-CT radiomics for outcome prediction in larynx and hypopharynx squamous cell carcinoma

To determine whether machine learning-based radiomic feature analysis of baseline integrated 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET) computed tomography (CT) predicts disease progression in patients with locally advanced larynx and hypopharynx squamous cell carcinoma (SCC) receiving (chemo)radiotherapy. Patients with larynx and hypopharynx SCC treated with definitive (chemo)radiotherapy at a specialist cancer centre undergoing pre-treatment PET-CT between 2008 and 2017 were included. Tumour segmentation and radiomic analysis was performed using LIFEx software (University of Paris-Saclay, France). Data were assigned into training (80%) and validation (20%) cohorts adhering to TRIPOD guidelines. A random forest classifier was created for four predictive models using features determined by recursive feature elimination: (A) PET, (B) CT, (C) clinical, and (D) combined PET-CT parameters. Model performance was assessed using area under the curve (AUC) receiver operating characteristic (ROC) analysis. Seventy-two patients (40 hypopharynx 32 larynx tumours) were included, mean age 61 (range 41-77) years, 50 (69%) were men. Forty-five (62.5%) had chemoradiotherapy, 27 (37.5%) had radiotherapy alone. Median follow-up 26 months (range 12-105 months). Twenty-seven (37.5%) patients progressed within 12 months. ROC AUC for models A, B, C, and D were 0.91, 0.94, 0.88, and 0.93 in training and 0.82, 0.72, 0.70, and 0.94 in validation cohorts. Parameters in model D were metabolic tumour volume (MTV), maximum CT value, minimum standardized uptake value (SUVmin), grey-level zone length matrix (GLZLM) small-zone low grey-level emphasis (SZLGE) and histogram kurtosis. FDG PET-CT derived radiomic features are potential predictors of early disease progression in patients with locally advanced larynx and hypopharynx SCC.

Evaluation of quantitative imaging parameters in head and neck squamous cell carcinoma.

Functional imaging such as 18F-fluoro-deoxy-glucose positron emission tomography/computed tomography (FDG-PET/CT), 18F-fluoro-misonidazole (F-MISO)-PET/CT, and diffusion-weighted magnetic resonance imaging (DW-MRI) can assess complex biological phenomena in tumors reflecting underlying disease biology. The aim of this prospective observational study was to correlate quantitative imaging parameters derived from pretreatment biological imaging such as FDG-PET/CT, F-MISO-PET/CT, and DW-MRI with each other and with clinical outcomes in patients with head and neck squamous cell carcinoma (HNSCC) treated with definitive radio(chemo)therapy. Twenty patients with pharyngo-laryngeal cancers underwent pretreatment biological imaging. Gross tumor volume (GTV) was delineated on axial planning CT (GTV<inf>CT</inf>). Quantitative FDG-PET/CT parameters included maximum, mean, minimum standardized uptake values (SUV<inf>max-FDG</inf>, SUV<inf>mean-FDG</inf>, SUV<inf>min-FDG</inf>); metabolic tumor volume (MTV); and total lesion glycolysis (TLG). F-MISO-PET/CT parameters included hypoxic tumor volume (HTV); maximum, mean, minimum SUV; and fractional hypoxic volume (FHV). Mean apparent diffusion coefficient (ADC<inf>mean</inf>) was derived from DW-MRI. There was moderately strong positive correlation (r=0.616, P=0.005) between GTV<inf>CT</inf> and MTV. HTV derived from F-MISO-PET/CT at 3-hours (HTV<inf>3hrs-F-MISO</inf>) showed strong positive correlation with GTV<inf>CT</inf> (r=0.753, P<0.0001) and MTV (r=0.796, P<0.0001) respectively. ADC<inf>mean</inf> showed strong positive correlations with SUV<inf>mean-5hrs-F-MISO</inf> (r=0.713, P=0.021) and SUV<inf>min-5hrs-F-MISO</inf> (r=0.731, P=0.016) respectively. A moderate negative correlation (r=-0.500, P=0.049) was observed between ADC<inf>mean</inf> and MTV. At a median follow up of 44 months, the 5-year Kaplan-Meier estimates of loco-regional control, disease-free survival, and overall survival were 53%, 43%, and 40% respectively. Larger volume of primary tumor (GTV<inf>CT</inf>>22cc and MTV>7.9cc) and increasing hypoxia (HTV<inf>3hr-F-MSO</inf>>4.9cc) were associated with worse outcomes. Functional imaging represents an attractive and non-invasive modality to assess complex biological phenomena in solid tumors. Larger tumor volume and increasing hypoxia emerged as putative prognostic imaging biomarkers in HNSCC.

Minimum Standardized Uptake Value from Quantitative Bone Single-Photon Emission Computed Tomography/Computed Tomography for Evaluation of Femoral Head Viability in Patients with Femoral Neck Fracture

Bone single-photon emission computed tomography/computed tomography (SPECT/CT) has been widely used for evaluation of femoral head viability in patients with femoral neck fracture. The current study aimed to investigate utility of standardized uptake value (SUV) from quantitative bone SPECT/CT for assessment of femoral head viability. From March 2015 to November 2018, quantitative bone SPECT/CT was performed in 9 patients with non-viable femoral head post femoral neck fracture and in 31 controls. Maximum (SUVmax), mean (SUVmean), and minimum standardized uptake values (SUVmin) were measured over femoral head and neck. Mann-Whitney U test with Bonferroni correction was used to compare SUVs of ipsilateral and contralateral femurs from femoral neck fracture patients with those of control femurs. As for femoral head viability, SUVmax and SUVmean were not significantly decreased in non-viable femoral heads compared to those in controls. Only the SUVmin was significantly reduced in non-viable femoral heads (mean ± standard deviation, 0.57 ± 0.38) than in controls (0.95 ± 0.26, p = 0.006) and contralateral femoral heads (1.36 ± 0.59, p = 0.008). The cutoff SUVmin of 0.61 (g/mL) yielded a sensitivity of 77.8% and specificity of 87.1% for detection of non-viable femoral heads (p = 0.006). Contralateral femoral necks of the femoral neck fracture patients showed significantly higher SUVmean and SUVmin (3.17 ± 1.20 and 1.64 ± 0.63) than those of controls (2.32 ± 0.53 and 1.04 ± 0.27; p = 0.021 and p = 0.002, respectively), which seemed to reflect weight bearing effect or metabolic derangement. The non-viable femoral heads from the femoral neck fracture showed significantly reduced SUVmin. Quantitative bone SPECT/CT holds promise for objective evaluation of femoral head viability.

High-Uptake Areas on &amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;F-FRP170 PET Image Necessarily Include Proliferating Areas in Glioblastoma: A Superimposed Image Study Combining &amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;F-FRP170 PET with &amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;C-methionine PET

Areas of uptake on positron emission tomography with 1-(2-[18F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole (FRP170 PET), a hypoxic cell radiotracer, can include regions retaining highly proliferative activity despite tissue hypoxia. The aim of this study was to clarify whether FRP170 image can detect densely populated hypoxic areas without proliferating potential in glioblastoma. We performed FRP170 PET scan and L-methyl-11C-methionine (MET) PET scan in eight patients with non-treated glioblastoma. Standardized uptake values (SUVs) within tumor and apparent normal brain were measured on each FRP170 and MET image for all patients. To visualize actively proliferative areas on MET image we initially extracted pixels showing a ratio of SUV in tumor to SUV in normal brain (T/N) > 1.6. For FRP170 image, we changed the thresholds between minimum SUV and maximum SUV in tumor. Pixels showing SUV above each threshold were extracted and superimposed on previously extracted pixels from MET image. We estimated whether pixels extracted with MET and FRP170 were visually separated on superimposed image for each pa-tient. When no threshold was established, uptake areas on MET image and FRP170 image overlapped widely on superimposed image in all patients. The higher threshold for FRP170 image diminished FRP170-extracted pixels, and shrunk overlapped areas on superimposed image. However, pixels extracted from FRP170 images could not be completely separated from pixels extracted from MET images in all patients, even with threshold raised to almost maximum SUV. The current findings suggest that uptake areas on FRP170 PET scan necessarily include proliferating areas in glioblastoma.

A Digital Reference Object to Analyze Calculation Accuracy of PET Standardized Uptake Value.

To determine the extent of variations in computing standardized uptake value (SUV) by body weight (SUV(BW)) among different software packages and to propose a Digital Imaging and Communications in Medicine (DICOM) reference test object to ensure the standardization of SUV computation between medical image viewing workstations. Research ethics board approval was not necessary because this study only evaluated images of a phantom. A synthetic set of positron emission tomographic (PET)/computed tomographic (CT) image data, called a digital reference object (DRO), with known SUV was created. The DRO was sent to 16 sites and evaluated on 21 different PET/CT display software packages. Users were asked to draw various regions of interest (ROIs) on specific features and report the maximum, minimum, mean, and standard deviation of the SUVs for each ROI. Numerical tolerances were defined for each metric, and the fraction of reported values within the tolerance was recorded, as was the mean, standard deviation, and range of the metrics. The errors in reported maximum SUV ranged from -37.8% to 0% for an isolated voxel with 4.11:1 target-to-background activity level, and errors in the reported mean SUV ranged from -1.6% to 100% for a region with controlled noise. There was also a range of errors in the less commonly used metrics of minimum SUV and standard deviation SUV. The variability of computed SUV(BW) between different software packages is substantial enough to warrant the introduction of a reference standard for medical image viewing workstations.

TU-F-12A-03: Using 18F-FDG-PET-CT and Deformable Registration During Head-And-Neck Cancer (HNC) Intensity Modulated Radiotherapy (IMRT) to Predict Treatment Response

Purpose: To evaluate the effect of deformable vs. rigid registration of pre-treatment 18F-FDG-PET-CT to intra-treatment 18F-FDG-PET-CT on different standardized uptake value (SUV) parameters and investigate which parameters correlate best with post-treatment response in patients undergoing IMRT for HNC. Methods: Pre-treatment and intra-treatment PET-CT (after 20Gy) scans were acquired, in addition to a 12 week post-treatment PET-CT to assess treatment response. Primary and lymph node gross tumor volumes (GTV_PRI and GTV_LN) were contoured on the pre-treatment CT. These contours were then mapped to intra-treatment PET images via rigid and deformable registration. Absolute changes from pre- to intra-treatment scans for rigid and deformable registration were extracted for the following parameters: SUV_MAX, SUV_MEAN, SUV_20%, SUV_40%, and SUV_60% (SUV_X% is the minimum SUV to the highest-intensity X% volume). Results: Thirty-eight patients were evaluated, with 27 available for classification as complete or incomplete response (CR/ICR). The pre-treatment average tumor volumes for the patients were 24.05cm3 for GTV_PRI and 23.4cm3 for GTV_LN. For GTV_PRI, there was no statistically significant difference between rigid vs. deformable registration across all ΔSUV parameters. For GTV_LN contours, all parameters were significantly different except for ΔSUV_MAX. For deformably-registered GTV_PRI, changes in the following metrics were significantly different for CR vs. ICR: SUV_MEAN(p=0.003), SUV_20%(p=0.02), SUV_40%(p=0.02), and SUV_60%(p=0.008). The following cutoff values separated CR from ICR with high sensitivity and specificity: ΔSUV_MEAN=1.49, ΔSUV_20%=2.39, ΔSUV_40%=1.80 and ΔSUV_60%=1.31. Corresponding areas under the Receiver Operating Characteristics curve were 0.90, 0.81, 0.81, and 0.85, respectively. Conclusion: Rigidly and deformably registered contours yielded statistically similar SUV parameters for GTV_PRI, but not GTV_LN. This implies that neither registration should be solely relied upon for nodal GTVs. Of the four SUV parameters found to be predictive of CR vs. ICR, SUV_MEAN was the strongest. Preliminary results show promise for using intra-treatment 18F-FDG-PET-CT with deformable registration to predict treatment response.

Postchemoradiotherapy Positron Emission Tomography Predicts Pathologic Response and Survival in Patients With Esophageal Cancer

To correlate the prechemoradiotherapy (CRT) and post-CRT metabolic tumor volume (MTV) on positron emission tomography (PET) scanning with the pathologic response and survival in patients receiving preoperative CRT for esophageal cancer. The medical records of 37 patients with histologically confirmed Stage I-IVA esophageal cancer treated with CRT with or without surgical resection were reviewed. Of the 37 patients, 21 received preoperative CRT (57%) and 16 received definitive CRT (43%). All patients had a pre-CRT and 32 had a post-CRT PET scan. The MTV was measured on the pre-CRT PET and post-CRT PET scan, respectively, using a minimum standardized uptake value (SUV) threshold x, where x = 2, 2.5, 3, or the SUV maximum × 50%. The total glycolytic activity (TGA(x)) was defined as the mean SUV × MTV(x). The MTV ratio was defined as the pre-CRT PET MTV/post-CRT MTV. The SUV ratio was defined similarly. A single pathologist scored the pathologic response using a tumor regression grade (TRG) scale. The median follow-up was 1.5 years (range, 0.4-4.9). No significant correlation was found between any parameters on the pre-CRT PET scan and the TRG or overall survival (OS). Multiple post-CRT MTV values and post-TGA values correlated with the TRG and OS; however, the MTV(2.5(Post)) and TGA(2.5(Post)) had the greatest correlation. The MTV(2) ratio correlated with OS. The maximum SUV on either the pre-CRT and post-CRT PET scans or the maximum SUV ratio did not correlate with the TRG or OS. Patients treated preoperatively had survival similar compared with those treated definitively with a good PET response (p = 0.97) and significantly better than that of patients treated definitively with a poor PET response (p < 0.0001). The maximum SUV was not a predictive or prognostic parameter. The MTV(2.5) and TGA(2.5) were useful markers for predicting the response and survival on the post-CRT PET scan. The MTV(2) ratio also correlated with survival. Post-CRT PET can potentially guide therapy after CRT.