Combination of MRI and dynamic FET PET for initial glioma grading

Summary Aim: MRI and PET with 18F-fluoro-ethyl-tyro- sine (FET) have been increasingly used to evaluate patients with gliomas. Our purpose was to assess the additive value of MR spectroscopy (MRS), diffusion imaging and dynamic FET-PET for glioma grading. Patients, methods: 38 patients (42 ± 15 aged, F/M: 0.46) with untreated histologically proven brain gliomas were included. All underwent conventional MRI, MRS, diffusion sequences, and FET-PET within 3±4 weeks. Performances of tumour FET time-activity-curve, early-to-middle SUVmax ratio, choline / creatine ratio and ADC histogram distribution pattern for gliomas grading were assessed, as compared to histology. Combination of these parameters and respective odds were also evaluated. Results: Tumour time-activity- curve reached the best accuracy (67%) when taken alone to distinguish between low and high-grade gliomas, followed by ADC histogram analysis (65%). Combination of time-activity-curve and ADC histogram analysis improved the sensitivity from 67% to 86% and the specificity from 63-67% to 100% (p < 0.008). On multivariate logistic regression analysis, negative slope of the tumour FET time-activity-curve however remains the best predictor of high-grade glioma (odds 7.6, SE 6.8, p = 0.022). Conclusion: Combination of dynamic FET-PET and diffusion MRI reached good performance for gliomas grading. The use of FET-PET/MR may be highly relevant in the initial assessment of primary brain tumours.

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

Nuklearmedizin ◽

10.1055/s-0038-1628898 ◽

1987 ◽

Vol 26 (06) ◽

pp. 248-252 ◽

Cited By ~ 3

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.

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Simulation study of a coincidence detection system for non-invasive determination of arterial blood time-activity curve measurements

EJNMMI Physics ◽

10.1186/s40658-020-00297-9 ◽

2020 ◽

Vol 7 (1) ◽

Author(s):

Yassine Toufique ◽

Othmane Bouhali ◽

Pauline Negre ◽

Jim O’ Doherty

Keyword(s):

Simulation Study ◽

Detection System ◽

Coincidence Detection ◽

Time Activity ◽

Time Activity Curve ◽

Non Invasive ◽

Arterial Blood ◽

Activity Curve

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Reliability of radionuclide gastroesophageal reflux studies using visual and time-activity curve analysis: inter-observer and intra-observer variation and description of minimum detectable reflux

Nuclear Medicine Communications ◽

10.1097/00006231-200304000-00012 ◽

2003 ◽

Vol 24 (4) ◽

pp. 421-428 ◽

Cited By ~ 7

Author(s):

M. CAGLAR ◽

B. VOLKAN ◽

R. ALPAR

Keyword(s):

Gastroesophageal Reflux ◽

Observer Variation ◽

Curve Analysis ◽

Time Activity ◽

Time Activity Curve ◽

Activity Curve

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Impulse-response function of splanchnic circulation with model-independent constraints: theory and experimental validation

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00054.2003 ◽

2003 ◽

Vol 285 (4) ◽

pp. G671-G680 ◽

Cited By ~ 15

Author(s):

Ole L. Munk ◽

Susanne Keiding ◽

Ludvik Bass

Keyword(s):

Portal Vein ◽

Impulse Response ◽

Response Function ◽

Mean Transit Time ◽

Impulse Response Function ◽

Parameter Estimates ◽

Time Activity ◽

Time Activity Curve ◽

Transit Times ◽

Activity Curve

Modeling physiological processes using tracer kinetic methods requires knowledge of the time course of the tracer concentration in blood supplying the organ. For liver studies, however, inaccessibility of the portal vein makes direct measurement of the hepatic dual-input function impossible in humans. We want to develop a method to predict the portal venous time-activity curve from measurements of an arterial time-activity curve. An impulse-response function based on a continuous distribution of washout constants is developed and validated for the gut. Experiments with simultaneous blood sampling in aorta and portal vein were made in 13 anesthetized pigs following inhalation of intravascular [15O]CO or injections of diffusible 3- O-[11C]methylglucose (MG). The parameters of the impulse-response function have a physiological interpretation in terms of the distribution of washout constants and are mathematically equivalent to the mean transit time ( T̄) and standard deviation of transit times. The results include estimates of mean transit times from the aorta to the portal vein in pigs: T̄ = 0.35 ± 0.05 min for CO and 1.7 ± 0.1 min for MG. The prediction of the portal venous time-activity curve benefits from constraining the regression fits by parameters estimated independently. This is strong evidence for the physiological relevance of the impulse-response function, which includes asymptotically, and thereby justifies kinetically, a useful and simple power law. Similarity between our parameter estimates in pigs and parameter estimates in normal humans suggests that the proposed model can be adapted for use in humans.

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