scholarly journals Method to Determine the Statistical Technical Variability of SUV Parameters

2021 ◽  
Author(s):  
Giulia Maria Rita De Luca ◽  
Jan Habraken
Keyword(s):  
Standard Deviation ◽  
Activity Ratio ◽  
Background Activity ◽  
Standardized Uptake Value ◽  
Lesion Size ◽  
Full Length ◽  
Acquisition Time ◽  
Technical Variability ◽  
Positron Emission ◽  
Bed Position

Abstract Background: Some of the parameters used for the quantification of Positron Emission Tomography (PET) images are the Standardized Uptake Value (SUV)Max, SUVMean and SUVPeak. In order to assess the significance of an increasing or decreasing of these parameters for diagnostic purposes it is relevant to know their standard deviation. The sources of the standard deviation can be divided in biological and technical. In this study we present a method to determine the technical variation of the SUV in PET images.Results: This method was tested on images of a NEMA quality phantom with spheres of various diameters with full-length acquisition time of 150 s per bed position and foreground to background activity ratio of F18-2-fluoro-2-deoxy-D-glucose (FDG) of 10:1. Our method is based on dividing the full-length 150 s acquisition into subsets of shorter time length and reconstructing the images in the subsets. The SUVMax, Mean and Peak were calculated for each reconstructed image in a subset. The coefficient of deviation of the SUV parameters within each subset has then been used to estimate the expected standard deviation between images at 150 s reconstruction length. We report the largest technical variation of the SUV parameters for the smallest sphere, and the smallest variation for the largest sphere. The expected variation at 150 s reconstruction length does not exceed 6% for the smallest sphere and 2% for the largest sphere. Conclusions: With the presented method we are able to determine the technical variation of SUV. The method enables us to evaluate the effect of parameter selection and lesion size on the technical variation, and therefore to evaluate its relevance on the total variation of the SUV value between studies.

scholarly journals Method to determine the standard deviation of SUV parameters

2020 ◽  
Author(s):  
Giulia Maria Rita De Luca ◽  
Jan B.A. Habraken
Keyword(s):  
Standard Deviation ◽  
Activity Ratio ◽  
Standardized Uptake Value ◽  
Lesion Size ◽  
Acquisition Time ◽  
Diagnostic Purpose ◽  
Original Dataset ◽  
Single Voxel ◽  
Bed Position ◽  
Original Acquisition

Abstract Some of the parameters used for the quantification of PET images are the Standardized Uptake Value (SUV)Max, SUVMean and SUVPeak. In order to assess the significance of an increasing or decreasing of these parameters for diagnostic purpose it is relevant to determine their standard deviation. In this study we present a method to determine the standard deviation of the SUV. Our method is based on dividing an original dataset into subsets of shorter time length. The variation between the SUV parameters of the subsets is used to estimate the standard deviation of the of the original acquisition. This method was tested on images of a NEMA quality phantom with acquisition time of 150 s per bed position and foreground to background activity ratio of 10:1. This original dataset has been reconstructed with different reconstruction lengths, generating new data subsets. The SUVMax, Mean and Peak were calculated for each image in the subsets. Their standard deviation has been calculated per subset for the different spheres included in the phantom. The variation of each subset has then been used to estimate the expected variation between images at 150 s reconstruction length. We report the largest standard deviation of the SUV parameters for the smallest sphere, and the smallest variation for the largest sphere. The expected variation at 150 s reconstruction length does not exceed 6% for the smallest sphere and 2% for the largest sphere. We also report a larger variation in SUVMax then in SUVMean and SUVPeak. This is in line with expectations that the standard deviation of the SUV Mean or SUVPeak parameter is lower, since the value of more voxels is included in the calculation, as opposed to the SUVMax, where a single voxel is decisive. With the presented method we are able to determine the standard deviation of SUV parameters and to evaluate the effect of parameter selection and lesion size on the standard deviation, and therefore to evaluate its relevance on the total variation of the SUV value between studies.

scholarly journals Method to Determine the Standard Deviation of SUV Parameters

2020 ◽  
Author(s):  
Giulia Maria Rita De Luca ◽  
Jan Habraken
Keyword(s):  
Standard Deviation ◽  
Standardized Uptake Value ◽  
Lesion Size ◽  
Acquisition Time ◽  
Original Dataset ◽  
Statistical Variation ◽  
Positron Emission ◽  
Bed Position ◽  
Original Acquisition ◽  
Time Frames

Abstract Some of the parameters used for the quantification of Positron Emission Tomography (PET) images are the Standardized Uptake Value (SUV)Max, SUV Mean and SUV Peak. In order to assess the significance of an increasing or decreasing of these parameters for diagnostic purposes it is relevant to determine their standard deviation. In this study we present a method to determine the range of statistical variation of the SUV in PET images. Our method is based on dividing an original dataset into subsets of shorter time-frames. The variation between the SUV parameters of the subsets is used to estimate the standard deviation of the of the original acquisition. This method was tested on images of a NEMA quality phantom with acquisition time of 150 s per bed position and foreground to background activity ratio of F18-2-fluoro-2-deoxy-D-glucose (FDG) of 10:1. This original dataset has been reconstructed with different reconstruction lengths, generating new data subsets. The SUV Max, Mean and Peak were calculated for each image in the subsets. Their standard deviation has been calculated per subset for the different spheres included in the phantom. The variation of each subset has then been used to estimate the expected variation between images at 150 s reconstruction length. We report the largest standard deviation of the SUV parameters for the smallest sphere, and the smallest variation for the largest sphere. The expected variation at 150 s reconstruction length does not exceed 6% for the smallest sphere and 2% for the largest sphere, but we report an higher coefficient of variation (up to 30%) for shorter reconstruction lengths. We also report significant differences in the variation of SUV parameters for the larger spheres. With the presented method we are able to determine the standard deviation of SUV parameters only due to and the statistical variation. The method enables us to evaluate the effect of parameter selection and lesion size on the standard deviation, and therefore to evaluate its relevance on the total variation of the SUV value between studies.

scholarly journals Post-reconstruction enhancement of [18F]FDG PET images with a convolutional neural network

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
John Ly ◽  
David Minarik ◽  
Jonas Jögi ◽  
Per Wollmer ◽  
Elin Trägårdh
Keyword(s):  
Neural Network ◽  
Image Quality ◽  
Convolutional Neural Network ◽  
Fdg Pet ◽  
Standardized Uptake Value ◽  
Test Group ◽  
Acquisition Time ◽  
Positron Emission ◽  
Bed Position

Abstract Background The aim of the study was to develop and test an artificial intelligence (AI)-based method to improve the quality of [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) images. Methods A convolutional neural network (CNN) was trained by using pairs of excellent (acquisition time of 6 min/bed position) and standard (acquisition time of 1.5 min/bed position) or sub-standard (acquisition time of 1 min/bed position) images from 72 patients. A test group of 25 patients was used to validate the CNN qualitatively and quantitatively with 5 different image sets per patient: 4 min/bed position, 1.5 min/bed position with and without CNN, and 1 min/bed position with and without CNN. Results Difference in hotspot maximum or peak standardized uptake value between the standard 1.5 min and 1.5 min CNN images fell short of significance. Coefficient of variation, the noise level, was lower in the CNN-enhanced images compared with standard 1 min and 1.5 min images. Physicians ranked the 1.5 min CNN and the 4 min images highest regarding image quality (noise and contrast) and the standard 1 min images lowest. Conclusions AI can enhance [18F]FDG-PET images to reduce noise and increase contrast compared with standard images whilst keeping SUVmax/peak stability. There were significant differences in scoring between the 1.5 min and 1.5 min CNN image sets in all comparisons, the latter had higher scores in noise and contrast. Furthermore, difference in SUVmax and SUVpeak fell short of significance for that pair. The improved image quality can potentially be used either to provide better images to the nuclear medicine physicians or to reduce acquisition time/administered activity.

scholarly journals Evaluation of qualitative and quantitative data of Y-90 imaging in SPECT/CT and PET/CT phantom studies

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246848
Author(s):  
Agata Kubik ◽  
Anna Budzyńska ◽  
Krzysztof Kacperski ◽  
Maciej Maciak ◽  
Michał Kuć ◽  
...  
Keyword(s):  
Background Activity ◽  
Observer Agreement ◽  
Qualitative Assessment ◽  
Acquisition Time ◽  
Qualitative And Quantitative ◽  
Pet Ct ◽  
Time Extension ◽  
Good Concordance ◽  
Phantom Studies ◽  
Bed Position

Introduction We aimed to assess the feasibility of SPECT and PET Y-90 imaging, and to compare these modalities by visualizing hot and cold foci in phantoms for varying isotope concentrations. Materials and methods The data was acquired from the Jaszczak and NEMA phantoms. In the Jaszczak phantom Y-90 concentrations of 0.1 MBq/ml and 0.2 MBq/ml were used, while higher concentrations, up to 1.0 MBq/ml, were simulated by acquisition time extension with respect to the standard clinical protocol of 30 sec/projection for SPECT and 30 min/bed position for PET imaging. For NEMA phantom, the hot foci had concentrations of about 4 MB/ml and the background 0.1 or 0.0 MBq/ml. All of the acquired data was analysed both qualitatively and quantitatively. Qualitative assessment was conducted by six observers asked to identify the number of visible cold or hot foci. Inter-observer agreement was assessed. Quantitative analysis included calculations of contrast and contrast-to-noise ratio (CNR), and comparisons with the qualitative results. Results For SPECT data up to two cold foci were discernible, while for PET four foci were visible. We have shown that CNR (with Rose criterion) is a good measure of foci visibility for both modalities. We also found good concordance of qualitative results for the Jaszczak phantom studies between the observers (corresponding Krippendorf’s alpha coefficients of 0.76 to 0.84). In the NEMA phantom without background activity all foci were visible in SPECT/CT images. With isotope in the background, 5 of 6 spheres were discernible (CNR of 3.0 for the smallest foci). For PET studies all hot spheres were visible, regardless of the background activity. Conclusions PET Y-90 imaging provided better results than Bremsstrahlung based SPECT imaging. This indicates that PET/CT might become the method of choice in Y-90 post radioembolization imaging for visualisation of both necrotic and hot lesions in the liver.

scholarly journals A case of primary aortic sarcoma with tumor infarction after stent graft placement

2021 ◽  
Vol 10 (11) ◽  
pp. 205846012110633
Author(s):  
Hiroki Nakamura ◽  
Akihiko Kanki ◽  
Hiroyuki Watanabe ◽  
Kentarou Ono ◽  
Noriaki Kuwada ◽  
...  
Keyword(s):  
Stent Graft ◽  
Standardized Uptake Value ◽  
Lesion Size ◽  
Mass Lesion ◽  
Mesenchymal Tumors ◽  
Graft Placement ◽  
Positron Emission ◽  
Thoracoscopic Biopsy ◽  
Enhanced Computed Tomography ◽  
Aortic Sarcoma

Primary aortic sarcoma is a very rare disease, and most primary aortic tumors are malignant mesenchymal tumors. We present the case of a 62-year-old man with sudden epigastric and back pain. Contrast-enhanced computed tomography (CT) revealed a mass lesion about 33.8 mm in diameter, in contact with the left side of the abdominal aorta. Impending rupture of an abdominal aortic aneurysm was suspected, so cardiovascular surgery for stent graft placement was performed the same day. Symptoms immediately improved and CT at 3 months postoperatively showed a marked decrease in lesion size, but the lesion subsequently grew again. Fluorodeoxyglucose (FDG)-positron emission tomography/CT was performed due to the possibility of malignant solid tumor, revealing markedly increased FDG accumulation (maximum standardized uptake value, 36.95) in the mass lesion. Primary aortic sarcoma was diagnosed from thoracoscopic biopsy. Here, we report a primary aortic sarcoma that shrank due to tumor infarction after stent graft placement, followed by tumor regrowth.

scholarly journals Digital PET/CT allows for shorter acquisition protocols or reduced radiopharmaceutical dose in [18F]-FDG PET/CT

2021 ◽  
Vol 35 (4) ◽  
pp. 485-492
Author(s):  
Ian Alberts ◽  
Christos Sachpekidis ◽  
George Prenosil ◽  
Marco Viscione ◽  
Karl Peter Bohn ◽  
...  
Keyword(s):  
Fdg Pet ◽  
Standardized Uptake Value ◽  
Small Variation ◽  
Acquisition Time ◽  
Perfect Agreement ◽  
Pet Ct ◽  
Digital Pet ◽  
Scan Data ◽  
Bed Position ◽  
Fdg Pet Ct

Abstract Purpose To establish the feasibility of shorter acquisition times (and by analogy, applied activity) on tumour detection and lesion contrast in digital PET/CT. Methods Twenty-one randomly selected patients who underwent oncological [18F]-FDG PET/CT on a digital PET/CT were retrospectively evaluated. Scan data were anonymously obtained and reconstructed in list-mode acquisition for a standard 2 min/bed position (bp), 1 min/bp and 30 s/bp (100%, 50% and 25% time or applied activity, respectively). Scans were randomized and read by two nuclear medicine physicians in a consensus read. Readers were blind to clinical details. Scans were evaluated for the number of pathological lesions detected. Measured uptake for lesions was evaluated by maximum and mean standardized uptake value (SUVmax and SUVmean, respectively) and tumour-to-backround ratio (TBR) were compared. Agreement between the three acquisitions was compared by Krippendorf’s alpha. Results Overall n = 100 lesions were identified in the 2 min and 1 min/bp acquisitions and n = 98 lesions in the 30 s/bp acquisitions. Agreement between the three acquisitions with respect to lesion number and tumour-to-background ratio showed almost perfect agreement (K’s α = 0.999). SUVmax, SUVmean and TBR likewise showed > 98% agreement, with longer acquisitions being associated with slightly higher mean TBR (2 min/bp 7.94 ± 4.41 versus 30 s/bp 7.84 ± 4.22, p < 0.05). Conclusion Shorter acquisition times have traditionally been associated with reduced lesion detectability or the requirement for larger amounts of radiotracer activity. These data confirm that this is not the case for new-generation digital PET scanners, where the known higher sensitivity results in clinically adequate images for shorter acquisitions. Only a small variation in the semi-quantitative parameters SUVmax, SUVmean and TBR was seen, confirming that either reduction of acquisition time or (by analogy) applied activity can be reduced as much as 75% in digital PET/CT without apparent clinical detriment.

Analysis of Myocardial Time-Activity Curves of 123l-Heptadecanoic Acid II. The Acquisition Time

1987 ◽  
Vol 26 (06) ◽  
pp. 248-252 ◽  
Author(s):  
M. J. van Eenige ◽  
F. C. Visser ◽  
A. J. P. Karreman ◽  
C. M. B. Duwel ◽  
G. Westera ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Acquisition Time ◽  
Half Time ◽  
Constant Ratio ◽  
Time Activity ◽  
Time Activity Curve ◽  
Time Value ◽  
Activity Curve ◽  
Low Amplitude ◽  
Parameter Values

Optimal fitting of a myocardial time-activity curve is accomplished with a monoexponential plus a constant, resulting in three parameters: amplitude and half-time of the monoexponential and the constant. The aim of this study was to estimate the precision of the calculated parameters. The variability of the parameter values as a function of the acquisition time was studied in 11 patients with cardiac complaints. Of the three parameters the half-time value varied most strongly with the acquisition time. An acquisition time of 80 min was needed to keep the standard deviation of the half-time value within ±10%. To estimate the standard deviation of the half-time value as a function of the parameter values, of the noise content of the time-activity curve and of the acquisition time, a model experiment was used. In most cases the SD decreased by 50% if the acquisition time was increased from 60 to 90 min. A low amplitude/constant ratio and a high half-time value result in a high SD of the half-time value. Tables are presented to estimate the SD in a particular case.

Usefulness of positron emission tomography for differentiating gliomas according to the 2016 World Health Organization classification of tumors of the central nervous system

2020 ◽  
Vol 133 (4) ◽  
pp. 1010-1019 ◽  
Author(s):  
Hiroaki Takei ◽  
Jun Shinoda ◽  
Soko Ikuta ◽  
Takashi Maruyama ◽  
Yoshihiro Muragaki ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Pet Imaging ◽  
Who Classification ◽  
Standardized Uptake Value ◽  
Emission Tomography ◽  
World Health ◽  
Pet Tracers ◽  
Positron Emission ◽  
Significant Difference ◽  
The Mean

OBJECTIVEPositron emission tomography (PET) is important in the noninvasive diagnostic imaging of gliomas. There are many PET studies on glioma diagnosis based on the 2007 WHO classification; however, there are no studies on glioma diagnosis using the new classification (the 2016 WHO classification). Here, the authors investigated the relationship between uptake of 11C-methionine (MET), 11C-choline (CHO), and 18F-fluorodeoxyglucose (FDG) on PET imaging and isocitrate dehydrogenase (IDH) status (wild-type [IDH-wt] or mutant [IDH-mut]) in astrocytic and oligodendroglial tumors according to the 2016 WHO classification.METHODSIn total, 105 patients with newly diagnosed cerebral gliomas (6 diffuse astrocytomas [DAs] with IDH-wt, 6 DAs with IDH-mut, 7 anaplastic astrocytomas [AAs] with IDH-wt, 24 AAs with IDH-mut, 26 glioblastomas [GBMs] with IDH-wt, 5 GBMs with IDH-mut, 19 oligodendrogliomas [ODs], and 12 anaplastic oligodendrogliomas [AOs]) were included. All OD and AO patients had both IDH-mut and 1p/19q codeletion. The maximum standardized uptake value (SUV) of the tumor/mean SUV of normal cortex (T/N) ratios for MET, CHO, and FDG were calculated, and the mean T/N ratios of DA, AA, and GBM with IDH-wt and IDH-mut were compared. The diagnostic accuracy for distinguishing gliomas with IDH-wt from those with IDH-mut was assessed using receiver operating characteristic (ROC) curve analysis of the mean T/N ratios for the 3 PET tracers.RESULTSThere were significant differences in the mean T/N ratios for all 3 PET tracers between the IDH-wt and IDH-mut groups of all histological classifications (p < 0.001). Among the 27 gliomas with mean T/N ratios higher than the cutoff values for all 3 PET tracers, 23 (85.2%) were classified into the IDH-wt group using ROC analysis. In DA, there were no significant differences in the T/N ratios for MET, CHO, and FDG between the IDH-wt and IDH-mut groups. In AA, the mean T/N ratios of all 3 PET tracers in the IDH-wt group were significantly higher than those in the IDH-mut group (p < 0.01). In GBM, the mean T/N ratio in the IDH-wt group was significantly higher than that in the IDH-mut group for both MET (p = 0.034) and CHO (p = 0.01). However, there was no significant difference in the ratio for FDG.CONCLUSIONSPET imaging using MET, CHO, and FDG was suggested to be informative for preoperatively differentiating gliomas according to the 2016 WHO classification, particularly for differentiating IDH-wt and IDH-mut tumors.

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