SUVmax of 2.5 should not be embraced as a magic threshold for separating benign from malignant lesions

Abstract

Lesions of an indeterminate nature are often encountered in images such as those from CT and MRI. Examples include solitary pulmonary nodules and various incidentalomas that may be found in any body region. FDG PET can be useful in differentiating benign from malignant lesions, given the fact that malignant lesions generally have a higher glycolytic rate and consequently higher FDG uptake. Both visual image interpretation and (semiquantitative) standardized uptake value (SUV) measurements may be used for this purpose. Some clinicians advocate the use of a maximum SUV (SUV max ) threshold of 2.5 to separate benign from malignant lesions, which is based on the results of several old studies that were published more than 10 years ago [1,2]. However, this approach suffers from major shortcomings, which may lead to patient mismanagement. This communication aims to clarify several important issues on the validity of using an SUV max threshold of 2.5 to differentiate benign from malignant lesions.First, SUV measurements are affected by many parameters, including the equipment used, the physics, and biological factors. Partial volume and spillover effects, attenuation correction, the reconstruction method and parameters for scanner type, the count noise bias effect, radiotracer distribution time (i.e. the time between radiotracer injection and imaging), competing transport effects, and body size all affect SUV measurements considerably [3]. Because of the variability in PET acquisition in different institutions [4], interinstitutional SUV measurements are likely to vary too. Consequently, thresholds such as the SUV max of 2.5 that have been reported as diagnostically useful by research groups in some institutions [1, 2], may not be useful at all in other institutions if different FDG PET protocols are used. In this context, initiatives such as the "EANM procedure guidelines for tumour PET imaging", which have been shown to significantly reduce variability in SUV across different centres [5], are of crucial importance.One important factor that should not be overlooked is the effect of partial volume effects on SUV measurements [6,7]. Because of the relatively low spatial resolution of PET, significant averaging of pixel intensities of lesions with the surrounding tissues occurs. Motion blurring (e.g. due to patient, cardiac and respiratory motion, and peristalsis) further leads to undesired averaging of pixel intensities of lesions with the surrounding tissues. If not corrected for, partial volume effects may lead to inaccurate (underestimated) measures of the true FDG activity, especially in small lesions [8][9][10]. Several methods can be used for partial volume correction, and these can be divided into methods applied at the regional level (e.g. use of recovery coefficients, geometric transfer matrix approach, and deconvolution) and methods applied at the pixel level (e.g. partition-based correction, multiresolution approach, fitting method, the so-called "maximum a posteriori" approach, and kinetic modelling) [9]. Pa...

Association of PET Scan Parameters of Pulmonary Masses and Reticuloendothelial System with Hematologic Parameters

“…Nguyen stated that a common threshold value for different sites was not feasible, but also reported SUVmax threshold >3.6 as highly sensitive and specific for pulmonary nodules [51]. Besides these findings, in some studies, it has been shown that quantitative analysis by PET scan did not improve accuracy [52][53][54]. Lobrano et al [55] investigated the effect of SUV of pulmonary mass in differentiating whether the masses were benign or malignant.…”

Actinomicosis amigdalina imitando una recaída de un linfoma no Hodgkin

“…El FDG puede ser útil para distinguir entre lesiones benignas y malignas, ya que la evidencia de malignidad tiene generalmente una tasa glucolítica más alta y por consiguiente mayor captación del FDG 12 . Algunos usan el umbral máximo del valor de captación estandarizado (SUV) de 2,5 para distinguirlos 12 . Sin embargo, las mediciones SUV dependen de varios parámetros: equipo utilizado, la física (scanner de variabilidad, cambios de parámetros de reconstrucción, error de calibración entre el scanner y calibrador de dosis, desfase entre scanner y calibrador de dosis, uso de material de contraste en TEP/TC, variabilidad interobservador) y factores biológicos (composición de peso, medición de tamaño corporal, corrección de glucosa en la sangre, equipo de captación post inyección, movimiento respiratorio) 12,13 .…”

“…Algunos usan el umbral máximo del valor de captación estandarizado (SUV) de 2,5 para distinguirlos 12 . Sin embargo, las mediciones SUV dependen de varios parámetros: equipo utilizado, la física (scanner de variabilidad, cambios de parámetros de reconstrucción, error de calibración entre el scanner y calibrador de dosis, desfase entre scanner y calibrador de dosis, uso de material de contraste en TEP/TC, variabilidad interobservador) y factores biológicos (composición de peso, medición de tamaño corporal, corrección de glucosa en la sangre, equipo de captación post inyección, movimiento respiratorio) 12,13 . Además, los procesos infecciosos e inflamatorios pueden conducir a un aumento de captación del FDG mucho mayor que el SUV 2,5, principalmente en lesiones infecciosas agudas 12,13 .…”

“…Además, los procesos infecciosos e inflamatorios pueden conducir a un aumento de captación del FDG mucho mayor que el SUV 2,5, principalmente en lesiones infecciosas agudas 12,13 . Debido a tantas variables, un SUV mayor de 2,5 no debe ser decisivo para diferenciar entre lesiones benignas y malignas 12 . Por consiguiente, debe ser necesario un estudio histopatologico para confirmar el diagnóstico.…”

18F-FDG PET-derived parameters as prognostic indices in hepatic malignancies after 90Y radioembolization: is there a role?

“…It is well known that SUV measurements can be affected by many issues, such as the reconstruction algorithm, the scanner used, the interval between tracer injection and the acquisition, the partial volume effect and so on [14]. Furthermore, SUV concerns information only on tumour metabolic activity and does not consider the overall tumoural volume.…”