TITLE:
The Specificity of a Diagnostic FDG-PET Study Is a Function of the Patient and the Location
AUTHORS:
Michael L. Goris
KEYWORDS:
FDG-PET, Specificity, Prevalence and Location
JOURNAL NAME:
Open Journal of Medical Imaging,
Vol.8 No.4,
December
18,
2018
ABSTRACT: The present paper is based
on the observations that 1) there is reported variation in the specificities
according to the type of tumor targeted (target) by FDG PET and 2) that while
one can posit that the sensitivity of the tracer depends on the avidity for
glucose and the plasma supply of the target, even so that the targeting cannot
influence the avidity of unrelated tissues or lesions. The hypothesis to be
tested is twofold: 1) patients imaged for different types of lesions could have
a different prevalence of FDG avid tissues or lesions different from the target
and 2) that the target lesions could be generally located in body location
(sites) more likely to contain unrelated foci of increased uptake. Variance
analysis shows that the sensitivity varies according to the target (p = 0.022),
but not according to the location (p = 0.34); the specificity varies with the
location (p = 0.0012) and the target (p = 0.05). Specificities are
significantly different in different primary targets and target locations. The
former is assumed to be due to different comorbidities in patients with
different targets, the latter to the different locations of unrelated glucose
avid organs or structures. Conclusion: When specificities are recorded
or defined, the patient population characteristics and the organ or pathology
of the false positives should also be described.