Cerebrovascular reactivity mapping for brain tumor presurgical planning

This article provides a review of Blood Oxygen Level Dependent functional magnetic resonance imaging(BOLD fMRI)applications for presurgical mapping in patients with brain tumors who are being considered for lesion resection.Initially,the physical principle of the BOLD effect is discussed,followed by a general overview of the aims of presurgical planning.Subsequently,a review of sensorimotor,language and visual paradigms that are typically utilized in clinical fMRI is provided,followed by a brief description of studies demonstrating the clinical impact of preoperative BOLD fMRI.After this thorough introduction to presurgical fMRI,a detailed explanation of the phenomenon of neurovascular uncoupling(NVU),a major limitation of fMRI,is provided,followed by a discussion of the different approaches taken for BOLD cerebrovascular reactivity(CVR)mapping,which is an effective method of detecting NVU.We then include one clinical case which demonstrates the value of CVR mapping in clinical preoperative fMRI interpretation.The paper then concludes with a brief review of applications of CVR mapping other than for presurgical mapping.

Presurgical Mapping of Brain Tumors Using Statistical Probabilistic Anatomical Maps

Purpose: Multi-tracer neuroimaging is widely used for the diagnosis, radiotherapy, and neuro-surgery of brain gliomas. Anatomical and functional information is important to avoid having neurological deficits induced during the resection or radiation therapy of brain gliomas. The aim of this study was to investigate presurgical anatomical labeling of brain gliomas on FLT and FET using statistical probabilistic anatomic maps (SPAM), which are images of cerebral cortical, cerebellar, and subcortical volumes of interest (VOIs). Methods: FDG, FLT, and FET PET scans were acquired. FLT and FET PET images were coregistered to the FDG PET images, which were then spatially normalized onto the target brain. An inverse spatial normalization parameter was calculated and applied to SPAM. For the anatomical labeling of brain glioma regions, the volumes of brain gliomason FLT and FET images were extracted using segmentation. Probabilistic information of the glioma region was then calculated using SPAM and the segmented glioma volumes. SPM and an in-house program were used for image processing. Results: The probability of SPAM labeling a brain glioma region could be extracted using the inverse normalized SPAM and segmented glioma regions. In a sample case, the probabilistic anatomical region of the glioma included 21% of the postcentral gyrus, 12% of the superior parietal gyrus, and 6% of the angular gyrus. Conclusion: Anatomical information about brain gliomas could be extracted using SPAM. This proposed method would be optional for presurgical mapping, to avoid an additional functional mapping study that might otherwise be necessary to avoid producing neurological deficits.

Finite element analysis application in presurgical planning:Treatment choise of temporomandibular joint ankylosis

Objective The aim of this study is to evaluate the applicable value of finite element analysis(FEA)for presurgical planning in the treatment of temporomandibular joint(TMJ)ankylosis.Methods CT image data of one patient with unilateral

Interictal and Ictal MEG in presurgical evaluation for epilepsy surgery

Although presurgical evaluation of patients with pharamacoresistent focal epilepsies provides essential information for successful epilepsy surgery,there is still a need for further improvement.Developments of noninvasive electrophysiological recording and analysis techniques offer additional information based on interictal and ictal epileptic activities.In this review,we provide an overview on the application of ictal magnetoencephalography(MEG).The results of a literature research for published interictal/ictal MEG findings and experiences with own cases are demonstrated and discussed.Ictal MEG may provide added value in comparison to interictal recordings.The results may be more focal and closer to the invasively determined seizure onset zone.In some patients without clear interictal findings,ictal MEG could provide correct localization.Novel recording and analysis techniques facilitate ictal recordings.However,extended recording durations,movement and artifacts still represent practical limitations.Ictal MEG may provide added value regarding the localization of the seizure onset zone but depends on the selection of patients and the application of optimal analysis techniques.

Clinical utility of cerebrovascular reactivity mapping in patients with low grade gliomas

AIM:To evaluate neurovascular uncoupling(NVU)associated with low grade gliomas(LGG)using blood oxygen level dependent(BOLD)cerebrovascular reactivity mapping.METHODS:Seven patients with low grade gliomas referred by neurosurgeons for presurgical mapping were included in this pilot study.Cerebrovascular reactivity(CVR)mapping was performed by acquiring BOLD images while patients performed a block-design breath-hold(BH)hypercapnia task.CVR mapping was expressed as BOLD percentage signal change(PSC)from baseline associated with performance of the BH hypercapnia task.Standard T2*Dynamic Susceptibility Contrast perfusion imaging was performed and relative cerebral blood volume(rCBV)and relative cerebral blood flow(rCBF)maps were generated.Structural T1 weighted MR images were also acquired.A correlation analysis between intratumoral normalized(via ratio with contralateral homologous regions)BOLD BH PSC[referred to as(nCVR)]and intratumoral normalized resting state rCBV(rCBF)values(i.e.,nCBV and nCBF,respectively)was performed.RESULTS:No significant correlation was seen between the normalized BOLD BH PSC(i.e.,nCBV)and nCBV or nCBF.However,the average nCVR(median=0.50,z=-2.28,P=0.01)was significantly less than 1.0,indicating abnormally reduced vascular responses in the tumor regions relative to normal contralesional homologous regions,whereas the average nCBV(median=0.94,z=-0.92,P=0.375)and nCBF(median=0.93,z=-1.16,P=0.25)were not significantly higher or lower than 1.0,indicating iso-perfusion in the tumor regions relative to normal contralesional homologous regions.These findings suggest that in LGG,hyperperfusion that is seen in high grade gliomas is not present,but,nevertheless,abnormally decreased regional CVR is present within and adjacent to LGG.Since the patients all demonstrated at least some residual function attributable to the cortical regions of impaired CVR,but were incapable of producing a BOLD response in these regions regardless of the tasks performed,such regionally decreased CVR is indicative of NVU.The low nCVR ratios indicate high prevalence of NVU in this LGG cohort,which is an important consideration in the interpretation of clinical presurgical mapping with functional magnetic resonance(MR)imaging.CONCLUSION:Our preliminary study shows that BH CVR mapping is clinically feasible and demonstrates an unexpectedly high prevalence of NVU in patients with LGG.

Computer-aided clinical image analysis as a predictor of sentinel lymph node positivity in cutaneous melanoma

BACKGROUND Delays in sentinel lymph node(SLN)biopsy may affect the positivity of non-SLNs.For these reasons,effort is being directed at obtaining reliable information regarding SLN positivity prior to surgical excision.However,the existing tools,e.g.,dermoscopy,do not recognize statistically significant predictive criteria for SLN positivity in melanomas.AIM To investigate the possible association of computer-assisted objectively obtained color,color texture,sharpness and geometry variables with SLN positivity.METHODS We retrospectively reviewed and analyzed the computerized medical records of all patients diagnosed with cutaneous melanoma in a tertiary hospital in Germany during a 3-year period.The study included patients with histologically confirmed melanomas with Breslow>0.75 mm who underwent lesion excision and SLN biopsy during the study period and who had clinical images shot with a digital camera and a handheld ruler aligned beside the lesion.RESULTS Ninety-nine patients with an equal number of lesions met the inclusion criteria and were included in the analysis.Overall mean(±standard deviation)age was 66(15)years.The study group consisted of 20 patients with tumor-positive SLN(SLN+)biopsy,who were compared to 79 patients with tumor-negative SLN biopsy specimen(control group).The two groups differed significantly in terms of age(61 years vs 68 years)and histological subtype,with the SLN+patients being younger and presenting more often with nodular or secondary nodular tumors(P<0.05).The study group patients showed significantly higher eccentricity(i.e.distance between color and geometrical midpoint)as well as higher sharpness(i.e.these lesions were more discrete from the surrounding normal skin,P<0.05).Regarding color variables,SLN+patients demonstrated higher range in all four color intensities(gray,red,green,blue)and significantly higher skewness in three color intensities(gray,red,blue),P<0.05.Color texture variables,i.e.lacunarity,were comparable in both groups.CONCLUSION SLN+patients demonstrated significantly higher eccentricity,higher sharpness,higher range in all four color intensities(gray,red,green,blue)and significantly higher skewness in three color intensities(gray,red,blue).Further prospective studies are needed to better understand the effectiveness of clinical image processing in SLN+melanoma patients.

Preoperative evaluation and surgical strategy for epileptic spasms in children

Epileptic spasm(ES)is one of the most common types of seizures in children.It is primarily characterized by brief axial contractions lasting less than 2 s and recurring in short clusters.It usually occurs in children of 3 to 12 months of age,although it can also occur after the age of 1 year.In general,children with ES develop other symptoms of epilepsy,such as tonic,tonic-clonic,or focal seizures,after 3 to 5 years of age.ES in children is often damaging and usually results in developmental regression.First-line treatments for spasm seizures include adrenocorticotropic hormone(ACTH)and vigabatrin.However,many patients fail to respond to these medications,and continued to have spasms associated with progressive neurodevelopmental degeneration.Therefore,it is important to consider whether children with drug resistance meet surgical indications to consider surgical treatment in such conditions.In this study,we reviewed and summarized the importance of preoperative evaluation in order to provide surgical options for treatment of children with ES.