http://incenter.medical.philips.com/doclib/enc/fetch/2000/4504/577242/577256/588821/5050628/5314862/6413113/FS40_WB-DWI_Leuven.pdf%3fnodeid%3d6412951%26vernum%3d1
Currently, after an initial diagnosis of primary cancer, routine
staging is performed on modalities such as CT, FDG-PET/(CT)
and bone scintigraphy, while MRI is often performed for problemsolving
or loco-regional staging. Diffusion weighted MRI (DWI) is
currently not commonly used for whole body staging because of
the relative immaturity of DWI applications and the time it takes
to fully evaluate lesions using ADC mapping. “This is not the case
with loco-regional DWI, where fewer lesions need to be evaluated,
making ADC-calculation less time consuming, and multiple b-values
can be used for ADC-calculation to assist in accurate lesion
characterization. However, such a time investment should be
avoided in whole body staging where finding suspicious lesions is
really the aim,” says Dr. Vandecaveye. “For this purpose, we accept
some loss in resolution and reduce the number of b-values to only
b0 and b1000. We also try to reduce the number of lesions that
require ADC calculation for characterization. Even though some
resolution is lost when going from localized to whole-body DWI,
we’re still able to see very small lesions down to 4 mm.
The challenge is to be able to assess from a single whole body scan
whether lesions need follow-up or not.”
Currently, after an initial diagnosis of primary cancer, routine
staging is performed on modalities such as CT, FDG-PET/(CT)
and bone scintigraphy, while MRI is often performed for problemsolving
or loco-regional staging. Diffusion weighted MRI (DWI) is
currently not commonly used for whole body staging because of
the relative immaturity of DWI applications and the time it takes
to fully evaluate lesions using ADC mapping. “This is not the case
with loco-regional DWI, where fewer lesions need to be evaluated,
making ADC-calculation less time consuming, and multiple b-values
can be used for ADC-calculation to assist in accurate lesion
characterization. However, such a time investment should be
avoided in whole body staging where finding suspicious lesions is
really the aim,” says Dr. Vandecaveye. “For this purpose, we accept
some loss in resolution and reduce the number of b-values to only
b0 and b1000. We also try to reduce the number of lesions that
require ADC calculation for characterization. Even though some
resolution is lost when going from localized to whole-body DWI,
we’re still able to see very small lesions down to 4 mm.
The challenge is to be able to assess from a single whole body scan
whether lesions need follow-up or not.”
