54
E. Liebenthal and T. Singhal
example, in brain receptor studies that require an assessment of changes in tracer
concentration over time to derive pharmacokinetic parameters.
From a surgical standpoint, the most common uses of brain PET imaging include
identification of a seizure focus and diagnostic and therapeutic planning in brain
tumour cases [113].
3.2 Clinical Applications of Brain Imaging for Image-Guided
Neurosurgery in Epilepsy and Brain Tumour Patients
The objective of presurgical and intrasurgical brain mapping is to obtain patientspecific structural and functional information that could facilitate maximal tumour
or epileptic tissue surgical resection while minimising damage to surrounding grey
and white matter structures supporting vital sensorimotor and cognitive functions.
Presurgical mapping of functional brain regions and their spatial relationship to a
brain lesion can help predict deficits in sensory, motor, or cognitive functions due
to surgery or due to continued lesion growth. Presurgical mapping can help guide
the decision for course of intervention (extent of resection, alternative treatment)
and the decision to conduct intrasurgical functional mapping. Presurgical mapping
is also valuable for planning of the surgical approach. Noninvasive neuroimaging
imposes less discomfort to the patient than invasive methods such as intra-arterial
amobarbital (Wada) testing, which requires a surgical procedure.
A limitation of presurgical mapping is that significant and difficult to predict
brain shifts, up to 20 mm in size, can occur during the surgery, primarily in
relation to craniotomy and tumour removal [41]. A variety of factors affect the
brain shift, including the tissue characteristics, intrasurgical patient positioning,
size of craniotomy, and the resected volume [85]. Presurgical information must
therefore be compensated for such brain shift throughout the surgery for accurate
registration to the intrasurgical space [83]. Estimation of intrasurgical brain shifts
can be achieved with intrasurgical ultrasound [53] or MRI [85, 110]. However,
accurate nonrigid registration of presurgical images to the intrasurgical space is
computationally expensive and time-consuming and therefore challenging for realtime implementation [6, 133]. Recent advances achieved in this field [32] are
discussed in detail in other chapters of this book.
A more recent application of MRI is for intrasurgical imaging, to detect residual
tumour or lesion tissue during surgery and minimise the need for corrective
surgery [18]. Intrasurgical MRI requires a dedicated intrasurgical MR scanner
or the adaptation of existing MRI scanner technology to the operating theatre
[3, 77]. Structural MRI is acquired in the operating room, usually after the
planned resection is completed, and sometimes also immediately after craniotomy
to estimate intrasurgical brain shifts. Intrasurgical MRI was shown to improve the
estimate of residual tumour burden compared to a subjective evaluation by the
operating neurosurgeon [15, 86, 106]. Presurgical structural and functional images
E. Liebenthal and T. Singhal
example, in brain receptor studies that require an assessment of changes in tracer
concentration over time to derive pharmacokinetic parameters.
From a surgical standpoint, the most common uses of brain PET imaging include
identification of a seizure focus and diagnostic and therapeutic planning in brain
tumour cases [113].
3.2 Clinical Applications of Brain Imaging for Image-Guided
Neurosurgery in Epilepsy and Brain Tumour Patients
The objective of presurgical and intrasurgical brain mapping is to obtain patientspecific structural and functional information that could facilitate maximal tumour
or epileptic tissue surgical resection while minimising damage to surrounding grey
and white matter structures supporting vital sensorimotor and cognitive functions.
Presurgical mapping of functional brain regions and their spatial relationship to a
brain lesion can help predict deficits in sensory, motor, or cognitive functions due
to surgery or due to continued lesion growth. Presurgical mapping can help guide
the decision for course of intervention (extent of resection, alternative treatment)
and the decision to conduct intrasurgical functional mapping. Presurgical mapping
is also valuable for planning of the surgical approach. Noninvasive neuroimaging
imposes less discomfort to the patient than invasive methods such as intra-arterial
amobarbital (Wada) testing, which requires a surgical procedure.
A limitation of presurgical mapping is that significant and difficult to predict
brain shifts, up to 20 mm in size, can occur during the surgery, primarily in
relation to craniotomy and tumour removal [41]. A variety of factors affect the
brain shift, including the tissue characteristics, intrasurgical patient positioning,
size of craniotomy, and the resected volume [85]. Presurgical information must
therefore be compensated for such brain shift throughout the surgery for accurate
registration to the intrasurgical space [83]. Estimation of intrasurgical brain shifts
can be achieved with intrasurgical ultrasound [53] or MRI [85, 110]. However,
accurate nonrigid registration of presurgical images to the intrasurgical space is
computationally expensive and time-consuming and therefore challenging for realtime implementation [6, 133]. Recent advances achieved in this field [32] are
discussed in detail in other chapters of this book.
A more recent application of MRI is for intrasurgical imaging, to detect residual
tumour or lesion tissue during surgery and minimise the need for corrective
surgery [18]. Intrasurgical MRI requires a dedicated intrasurgical MR scanner
or the adaptation of existing MRI scanner technology to the operating theatre
[3, 77]. Structural MRI is acquired in the operating room, usually after the
planned resection is completed, and sometimes also immediately after craniotomy
to estimate intrasurgical brain shifts. Intrasurgical MRI was shown to improve the
estimate of residual tumour burden compared to a subjective evaluation by the
operating neurosurgeon [15, 86, 106]. Presurgical structural and functional images