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PubMed2002

Comparison of spatial normalization procedures and their impact on functional maps.

The alignment accuracy and impact on functional maps of four spatial normalization procedures have been compared using a set of high resolution brain MRIs and functional PET volumes acquired in 20 subjects. Simple affine (AFF), fifth order polynomial warp (WRP), discrete cosine basis functions (SPM), and a movement model based on full multi grid (FMG) approaches were applied on the same dataset for warping individual volumes onto the Human Brain Atlas (HBA) template. Intersubject averaged structural volumes and tissue probability maps were compared across normalization methods and to the standard brain. Thanks to the large number of degrees of freedom of the technique, FMG was found to provide enhanced alignment accuracy as compared to the other three methods, both for the grey and white matter tissues; WRP and SPM exhibited very similar performances whereas AFF had the lowest registration accuracy. SPM, however, was found to perform better than the other methods for the intra-cerebral cerebrospinal fluid (mainly in the ventricular compartments). Limited differences in terms of activation morphology and detection sensitivity were found between low resolution functional maps (FWHM approximately 10 mm) spatially normalized with the four methods, which overlapped in 42.8% of the total activation volume. These findings suggest that the functional variability is much larger than the anatomical one and that precise alignment of anatomical features has low influence on the resulting intersubject functional maps. When increasing the spatial resolution to approximately 6 mm, however, differences in localization of activated areas appear as a consequence of the different spatial normalization procedure used, restricting the overlap of the normalized activated volumes to only 6.2%.

Adult↗

PubMed2000

Efficiency and accuracy of two computerized topography software systems for fitting rigid gas permeable contact lenses.

PURPOSE: The world of computerized videokeratoscopy is continually evolving. Computerized videokeratoscope contact lens programs boast the capability to accurately design final rigid gas permeable (RGP) lens parameters and simulate contact lens fluorescein patterns. We evaluated the EyeSys System 2000 Pro-Fit software (v. 4.0) and Humphrey Atlas MasterVue Contact Lens Module (v. A6) for efficiency and accuracy in fitting RGP contact lenses on normal subjects. METHODS: Balanced manifest refractions, slit lamp examinations, and computerized topographical analysis with RGP module lens fitting were performed and compared for all eyes. Lens parameters were chosen after an optimal simulated fluorescein pattern was achieved by either accepting the initially recommended default lens or a modification. Final lens parameters were based on clinical performance. RESULTS: With the Humphrey Atlas software, which uses a default topographic tear clearance fitting protocol set by the manufacturer, 24/50 (48%) eyes required modifications to the default fitting parameters based on the simulated fluorescein patterns. Nine of 50 eyes (18%) required further modifications once the RGP lens was dispensed. The EyeSys Pro-Fit software, which allows a custom tear clearance fitting protocol set by the user as default, required modifications to 20/35 eyes (57.1%) from default fittings provided by the system. Six of 35 eyes (17.1%) required subsequent modifications once the RGP lens was dispensed. Comparison of the EyeSys to Humphrey modules revealed no significant difference in efficiency (P=0.51), defined as any changes required to the default parameters; however, the user made more modifications to the EyeSys module from the default setting. There was no significant difference in final success rates between EyeSys (82.9%) and Humphrey (82%) systems (P=1.00). CONCLUSION: Although both topography guided contact lens modules offered accuracy in RGP fitting, a user programmed default (EyeSys) protocol did not improve efficiency in RGP lens parameter selection compared to a manufacturer programmed default module (Humphrey). The need for a knowledgeable contact lens fitter remains to guide the systems in achieving the optimal fit.

Contact Lenses↗

PubMed2001

Profiling of differential gene expression in Wilms tumor by cDNA expression array.

In order to identify genes or pathways involved in Wilms tumor etiology, we used the Atlas Cancer cDNA expression array to compare the gene expression profiles of five tumors, one Wilms tumor cell line (SK-NEP1), and normal mature and fetal kidneys. Of 588 genes tested, 153 had a different expression pattern in tumors compared with mature kidney. Ninety-six genes were differentially expressed in tumors compared with both normal mature and fetal kidney, and 57 genes had expression profiles similar to that of fetal kidney, which may reflect the developmental stage of the tumor cells. Comparison of the expression patterns of tumors shows that only 13% of the differentially expressed genes are constantly up- or downregulated in the five tumors tested, and this provides molecular evidence of tumor heterogeneity. We then confirmed the differential expression by an independent method, using quantitative reverse transcriptase polymerase chain reaction for two of the differentially expressed genes, MMP-14 and cyclin D2. Analysis of expression levels in a panel of 40 tumors showed that 30% overexpressed MMP-14 and 80% overexpressed cyclin D2. Profiling of gene expression using cDNA arrays in a large tumor panel will ultimately lead to the molecular classification of tumors, the identification of prognosis markers, and the design of targeted therapy.

Cyclin D2↗

PubMed2001

Regional cerebral blood flow as assessed by principal component analysis and (99m)Tc-HMPAO SPET in healthy subjects at rest: normal distribution and effect of age and gender.

The increasing implementation of standardisation techniques in brain research and clinical diagnosis has highlighted the importance of reliable baseline data from normal control subjects for inter-subject analysis. In this context, knowledge of the regional cerebral blood flow (rCBF) distribution in normal ageing is a factor of the utmost importance. In the present study, rCBF was investigated in 50 healthy volunteers (25 men, 25 women), aged 31-78 years, who were examined at rest by means of single-photon emission tomography (SPET) using technetium-99m d, l-hexamethylpropylene amine oxime (HMPAO). After normalising the CBF data, 27 left and 27 right volumes of interest (VOIs) were selected and automatically outlined by standardisation software (computerised brain atlas). The heavy load of flow data thus obtained was reduced in number and grouped in factors by means of principal component analysis (PCA). PCA extracted 12 components explaining 81% of the variance and including the vast majority of cortical and subcortical regions. Analysis of variance and regression analyses were performed for rCBF, age and gender before PCA was applied and subsequently for each single extracted factor. There was a significantly higher CBF on the right side than on the left side ( P<0.001). In the overall analysis, a significant decrease was found in CBF ( P=0.05) with increasing age, and this decrease was particularly evident in the left hemisphere ( P=0.006). When gender was specifically analysed, CBF was found to decrease significantly with increasing age in females ( P=0.037) but not in males. Furthermore, a significant decrease in rCBF with increasing age was found in the brain vertex ( P=0.05), left frontotemporal cortex ( P=0.012) and temporocingulate cortex ( P=0.003). By contrast, relative rCBF in central structures increased with age ( P=0.001). The ability of standardisation software and PCA to identify functionally connected brain regions might contribute to a better understanding of the relationships between rCBF at rest, anatomically defined brain structures, ageing and gender.

Adult↗

PubMed2003

Self-referred whole-body CT imaging: current implications for health care consumers.

PURPOSE: To conduct an empirical analysis of self-referred whole-body computed tomography (CT) and develop a profile of the geographic and demographic distribution of centers, types of services and modalities, costs, and procedures for reporting results. MATERIALS AND METHODS: An analysis was conducted of Web sites for imaging centers accepting self-referred patients identified by two widely used Internet search engines with large indexes. These Web sites were analyzed for geographic location, type of screening center, services, costs, and procedures for managing imaging results. Demographic data were extrapolated for analysis on the basis of center location. Descriptive statistics, such as frequencies, means, SDs, ranges, and CIs, were generated to describe the characteristics of the samples. Data were compared with national norms by using a distribution-free method for calculating a 95% CI (P <.05) for the median. RESULTS: Eighty-eight centers identified with the search methods were widely distributed across the United States, with a concentration on both coasts. Demographic analysis further situated them in areas of the country characterized by a population that consisted largely of European Americans (P <.05) and individuals of higher education (P <.05) and socioeconomic status (P <.05). Forty-seven centers offered whole-body screening; heart and lung examinations were most frequently offered. Procedures for reporting results were highly variable. CONCLUSION: The geographic distribution of the centers suggests target populations of educated health-conscious consumers who can assume high out-of-pocket costs. Guidelines developed from within the profession and further research are needed to ensure that benefits of these services outweigh risks to individuals and the health care system.

Humans↗

PubMed2001

Single- versus multi-detector row CT of the brain: quality assessment.

PURPOSE: To assess the quality of brain computed tomographic (CT) studies obtained with a four-channel multi-detector row CT scanner compared with those obtained with a single-detector row CT scanner. MATERIALS AND METHODS: Forty-seven patients referred for brain CT were imaged with both single- and multi-detector row scanners. Single-detector row CT images were acquired by using a 5-mm-collimated beam in the transverse mode. Multi-detector row CT images were acquired in four simultaneous 2.5-mm-thick sections, which were combined in projection space to create two contiguous 5-mm-thick sections. Two neuroradiologists blinded to the acquisition technique independently evaluated the CT image pairs, which were presented in a stacked mode on two adjacent monitors. Each study was graded by using a five-point scale for posterior fossa artifact, overall image quality, and overall preference. RESULTS: Multi-detector row CT studies were acquired 1.8 times faster than single-detector row CT studies (0.92 vs 0.52 section per second). Multi-detector row CT posterior fossa artifact was less than single-detector row CT posterior fossa artifact in 87 (93%) of 94 studies. Overall preference was expressed for multi-detector row CT in 84 (89%) of 94 studies. The differences in mean posterior fossa artifact scores (P <.001) and mean overall image quality scores (P =.001) were significant. CONCLUSION: Brain CT images obtained with multi-detector row CT resulted in significantly less posterior fossa artifact and were preferred to single-detector row CT images.

Artifacts↗

PubMed2001

MR-based statistical atlas of the Göttingen minipig brain.

Thedomestic pig is increasingly being used as an experimental model for brain imaging studies with positron emission tomography (PET). The recording of radiotracer uptake by PET gives functional and physiological information, but with poor spatial resolution. To date, anatomical regions of interest in pig brain have been defined in MR images obtained for each individual animal, because of the lack of a standard stereotaxic coordinate system for the pig brain. In order to define a stereotaxic coordinate system, we coregistered T1-weighted MR images from 22 male Göttingen minipigs and obtained a statistically defined surface rendering of the average minipig brain in which stereotaxic zero is defined by the position of the pineal gland. The average brain is now used as a target for registration of dynamic PET data, so that time-activity curves can be extracted from standard volumes of interest. In order to define these volumes, MR images from each individual pig were manually segmented into a total of 34 brain structures, including cortical regions, white matter, caudate and putamen, ventricular system, and cerebellum. The mean volumes of these structures had variances in the range of 10-20%. The 34 brain volumes were transformed into the common coordinate system and then used to generate surface renderings with probabilistic threshold greater than 50%. This probabilistic threshold gave nearly quantitative recovery of the mean volumes in native space. The probabilistic volumes in stereotaxic space are now being used to extract time-radioactivity curves from dynamic PET recordings.

Animals↗

PubMed2003

Measures of health-related quality of life for adults with acute sinusitis. A systematic review.

CONTEXT: Symptoms suggestive of acute sinusitis are a common reason for patients to visit primary care providers. Since objective measures of outcome have not been shown to be related to patient reported outcomes, measures of treatment success have focused on symptom relief and improved health-related quality of life (HRQL). Assessing the appropriate role of treatment - for example, antibiotics for patients with acute sinusitis - requires valid, reliable, and responsive measures of outcome. We identified symptom scores and HRQL instruments for adults with sinusitis and assessed their performance characteristics. DATA SOURCES: Articles identified through computer searches of the medline, premedline, and embase databases, the Cochrane Library, and internet documents; inquiries to experts in sinusitis and outcomes assessment; and review of reference lists. STUDY SELECTION: Studies that used HRQL instruments or evaluated the performance characteristics of symptom scores in adults with sinusitis, published in English after 1966. DATA EXTRACTION: Two reviewers independently extracted data on study design, setting, and patient characteristics; instrument length and format; and instrument validity, reliability, responsiveness to change, and interpretability. Study quality was assessed using a 10-point score. DATA SYNTHESIS: Of 1,340 articles in the original search, 29 articles using 16 HRQL instruments and 5 symptoms scores met inclusion and exclusion criteria. The overall quality of these studies was low; only 4 studies scored higher than 4 of 10 points. Four studies included patients with acute sinusitis, but only 2 included exclusively acute sinusitis patients. Three instruments have been shown to meet basic requirements for validity, reliability, and responsiveness: the Chronic Sinusitis Survey, the Rhinosinusitis Outcome Measure-31, and the Sinonasal Outcome Test-16. No instrument has been validated in a primary care setting or for patients with acute sinusitis. CONCLUSIONS: Few validated measures of sinusitis-specific HRQL are available. The 3 instruments shown to be valid, reliable, and responsive have been assessed in patients with chronic sinusitis. No measure has been validated in primary care settings or for patients with acute sinusitis. A lack of valid, responsive outcome measures may limit current treatment recommendations for patients with acute sinusitis.

Acute Disease↗

PubMed2005

Anatomic considerations for the pedicle screw placement in the first cervical vertebra.

STUDY DESIGN: Anatomic bony measurements were manually performed on 50 dry atlantoaxial vertebral complexes with an electronic digital caliper, and a reliable landmark for insertion of a pedicle screw in C1 vertebra was described and evaluated. OBJECTIVES: To investigate the feasibility of placing a screw in the C1 pedicle and evaluate the reliability of the C2 lateral mass as a landmark for determining the optimal site of screw entry. SUMMARY OF BACKGROUND DATA: The use of C1-C2 pedicle screws with the additional rods or plates has been an alternative method of stabilization for patients who are unsuitable for C1-C2 transarticular screw stabilization. However, the optimal portal of entry for the C1 pedicle screw is difficult to determine during surgery in the absence of reliable reference landmarks and sufficient relevant anatomic studies. METHODS: We manually measured 11 linear anatomic parameters related to the C1 lateral mass, its pedicle and posterior arch under the groove on 50 pairs of dry C1-C2 complexes harvested from cadavers. We also treated five patients with atlantoaxial instability with C1 and C2 pedicle screw fixation; the entry point of the C1 pedicle screw was ascertained by using C2 lateral mass as a landmark, and the position of the C1 pedicle screws in each case was evaluated with postoperative radiographs and computed tomography scans. RESULTS: The mean mediolateral width and rostrocaudal height of C1 pedicle were 8.57 and 5.83 mm, respectively. The mean rostrocaudal height of C1 posterior lamina at the reference entry point for the screw was 4.59 mm. The mean rostrocaudal height of the C1 posterior arch under the vertebral artery groove was 3.88 mm at its medial one-third and 4.25 mm at its lateral one-third. The thinnest external diameter of the screw tract that was recorded was <4 mm in six (12%) specimens of C1 vertebrae. The center of C2 lateral mass was 1.51 mm lateral to the sagittal plane of the mediolateral midpoint of the C1 pedicle. The distance from the suggested screw entry point to C1 posterior tubercle was 22.15 mm, and the mean length of the screw tract was 28.55 mm. Ten C1 pedicle screws were placed exactly, without neural or vascular injury in all five patients. CONCLUSION: The heights of the C1 pedicle, the posterior arch under the groove and the posterior lamina at the screw entry point are the major determinants for the possibility of placing pedicle screws in C1 of a given patient. This study indicates that it is feasible to place a 3.5-mm pedicle screw safely in C1 in most patients, and the lateral mass of C2 is a reliable anatomic landmark that can be easily identified to help the surgeon determine the optimal screw entry portal conveniently during surgery.

Adult↗

PubMed2005

Automated brain tissue assessment in the elderly and demented population: construction and validation of a sub-volume probabilistic brain atlas.

OBJECTIVES: To develop an automated imaging assessment tool that accommodates the anatomic variability of the elderly and demented population as well as the registration errors occurring during spatial normalization. METHODS: 20 subjects with Alzheimer's disease (AD), mild cognitive impairment, or normal cognition underwent MRI brain imaging and had their 3D volumetric datasets manually partitioned into 68 regions of interest (ROI) termed sub-volumes. Gray matter (GM), white matter (WM), and cerebral spinal fluid (CSF) voxel counts were then made in the subject's native space for comparison against automated volumetric measures within three sub-volume probabilistic atlas (SVPA) models. The three SVPAs were constructed using 12 parameter affine (12 p), 2nd order (2nd), and 6th order (6th) transforms derived from registering the manually partitioned scans into a Talairach compatible AD population-based target. The three SVPA automated measures were compared to the manually derived measures in the 20 subjects' native space with a "jack-knife" procedure in which each subject was assessed by an SVPA they did not contribute toward constructing. RESULTS: The mean left and right GM ratio (GM ratio = [GM + CSF] / CSF) "r values" for the 3 SVPAs compared to the manually derived ratios across the 68 ROIs were 0.85 for the 12p SVPA, 0.88 for the 2nd SVPA, and 0.89 for the 6th SVPA. The mean left and right WM ratio (WM ratio = [WM + CSF] / CSF) "r values" for the 3 SVPAs being 0.84 for the 12p SVPA, 0.86 for the 2nd SVPA, and 0.88 for the 6th SVPA. CONCLUSION: We have constructed, from an elderly and demented cohort, an automated brain volumetric tool that has excellent accuracy compared to a manual gold standard and is capable of regional hypothesis testing and individual patient assessment compared to a population.

Aged↗

PubMed2005

A human protein atlas for normal and cancer tissues based on antibody proteomics.

Antibody-based proteomics provides a powerful approach for the functional study of the human proteome involving the systematic generation of protein-specific affinity reagents. We used this strategy to construct a comprehensive, antibody-based protein atlas for expression and localization profiles in 48 normal human tissues and 20 different cancers. Here we report a new publicly available database containing, in the first version, approximately 400,000 high resolution images corresponding to more than 700 antibodies toward human proteins. Each image has been annotated by a certified pathologist to provide a knowledge base for functional studies and to allow queries about protein profiles in normal and disease tissues. Our results suggest it should be possible to extend this analysis to the majority of all human proteins thus providing a valuable tool for medical and biological research.

Antibodies↗

PubMed2006

Rapid and automatic localization of the anterior and posterior commissure point landmarks in MR volumetric neuroimages.

RATIONALE AND OBJECTIVE: Accurate identification of the anterior commissure (AC) and posterior commissure (PC) is critical in neuroradiology, functional neurosurgery, human brain mapping, and neuroscience research. Moreover, major stereotactic brain atlases are based on the AC and PC. Our goal is to provide an algorithm for a rapid, robust, accurate and automatic identification of AC and PC. MATERIALS AND METHOD: The method exploits anatomical and radiological properties of AC, PC and surrounding structures, including morphological variability. The localization is done in two stages: coarse and fine. The coarse stage locates the AC and PC on the midsagittal plane by analyzing their relationships with the corpus callosum, fornix, and brainstem. The fine stage refines the AC and PC in a well-defined volume of interest, analyzing locations of lateral and third ventricles, interhemispheric fissure, and massa intermedia. RESULTS: The algorithm was developed using simple operations, like histogramming, thresholding, region growing, 1D projections. It was tested on 94 diversified T1W and SPGR datasets. After the fine stage, 71 (76%) volumes had an error between 0-1 mm for the AC and 55 (59%) for the PC. The mean errors were 1.0 mm (AC) and 1.0 mm (PC). The accuracy has improved twice due to fine stage processing. The algorithm took about 1 second for coarse and 4 seconds for fine processing on P4, 2.5 GHz. CONCLUSION: The use of anatomical and radiological knowledge including variability in algorithm formulation aids in localization of structures more accurately and robustly. This fully automatic algorithm is potentially useful in clinical setting and for research.

Algorithms↗

PubMed2004

Pitfalls of magnetic resonance imaging of alar ligament.

An observational study of variations in the appearance of the alar ligament on magnetic resonance imaging (MRI) and the normal range of lateral flexion and rotation of the atlas was performed to validate some of the premises underlying the use of MRI for the detection of injuries to the alar ligament. Fifteen healthy volunteers were included. Three sets of coronal proton-density images, and axial T2-weighted images of the craniovertebral junction, were obtained at 0.5 T with the neck in neutral position and laterally flexed (coronal proton density) or rotated (axial T2). Five of the subjects also underwent imaging at 1.5 T. The scans were independently examined twice by two radiologists. The presence of alar ligaments was recorded and a three-point scale used to grade the extent of hyperintensity exhibited by the structures: the ligament were graded as 2 and 3 if, respectively, less or more of its cross-section was hyperintense, whereas grade 1 represented a hypointense ligament. The effect of lateral flexion on image quality was assessed. Concordance analysis of the data were performed before and after dichotomising the data on grading. The atlanto-axial angle and rotation of the atlas were measured. The magnitude of movement to right was normalised to that to the left to give, respectively, the flexion index and the rotation index. The alar ligaments were most reliably seen on coronal proton-density scans, with a Maxwell's RE of 0.96 as compared with 0.46 for sagittal images. Flexion of the neck improved definition of the ligaments in only rare instances. Inter-observer disagreement was marked with respect to grading of the ligament on both coronal [composite proportion of agreement (p0)=0.44; 95% confidence intervals: 0.26, 0.64)] and sagittal scans [p0=0.40 (0.19, 0.63)]. Dichotomising the data did not appreciably improve reliability [Maxwell's RE: -0.11 (coronal scans), -0.20 (sagittal scans)]: for ligaments which demonstrated hypertensive areas (grades 2 and 3) there was complete lack of agreement for both coronal [p2=0 (0, 0.25)] and sagittal scans [p2=0 (0-0.30)]. A large response bias was found in the reports of both readers albeit in opposite directions. There was poor concordance between scans obtained at different field strengths [RE (coronal images)=0.25; RE (sagittal images)=0.14). Mean flexion index and mean rotation index were 1.00 (SD 0.03) and 1.01 (SD 0.06), respectively. The MR imaging may not be the investigation of choice for the investigation of subtle injuries to the alar ligament. Whether it can be substituted by kinematic assessment of the occipito-atlanto-axial complex with MRI warrants investigation.

Adult↗

PubMed2026

Afirma genomic sequencing classifier performance in young patients with cytologically indeterminate thyroid nodules.

CONTEXT: The Afirma Genomic Sequencing Classifier (GSC) is validated in patients ≥ 21 years with a 96% negative predictive value for malignancy when GSC-(B)enign. Afirma GSC has not been formally studied in patients <21 years of age with indeterminate thyroid nodules (ITNs). OBJECTIVE: To evaluate Afirma GSC in young patients with ITNs. DESIGN: Retrospective analysis of Afirma GSC testing. SETTING: ITNs referred for molecular testing in a real-world setting. PARTICIPANTS: Forty-nine ITNs from 49 patients < 21 years of age who had histopathology or 2 years' clinical follow-up data ascertained. INTERVENTION: None. MAIN OUTCOME MEASURE: Afirma GSC test performance. RESULTS: In 49 ITNs from patients aged 9 to 20 years (median 18.5 [interquartile range, 17.3-19.8]), 30 were GSC-B and 19 GSC-(S)uspicious, among which 14 (73.7%) were malignant (ie, true positive) and 5 (26.3%) were benign (ie, false positive). All 30 Afirma GSC-B cases were either histologically (n = 9) or clinically benign (n = 21) (ie, true negative). All 14 malignancies were GSC-S (sensitivity 100% [95% CI, 77-100]); 30/35 clinically or histologically benign cases were GSC-B (specificity 86% [95% CI, 70-95]). Negative predictive value for an Afirma GSC-B result was 100% [95% CI, 88-100]. Genomic alterations were not detected in the 30 GSC-B samples. Among the 14 malignant samples, there were 9 papillary thyroid carcinomas, 1 oncocytic carcinoma, 1 noninvasive follicular thyroid neoplasm with papillary-like nuclear features, and 3 follicular thyroid carcinomas. CONCLUSION: In young patients with ITNs, the Afirma GSC demonstrated an excellent negative predictive value when defining a thyroid nodule result by histology or clinical follow-up.

Thyroid Nodule↗

PubMed1998

Use of significance image to determine patterns of cortical blood flow abnormality in pathological and at-risk groups.

UNLABELLED: The purpose of this work was to determine whether certain pathological groups and other groups at risk for neurological damage exhibited distinctive patterns of regional cerebral blood flow (rCBF) abnormality. METHODS: HMPAO SPECT images obtained from six groups of subjects were compared with a normal cortical rCBF atlas, based on multivariate, voxel-by-voxel methods. In each case, a significance image was outputted, highlighting voxels with deficits of > or =3 s.d. of normal. Abnormal patterns were examined for the six groups, which comprised a further 40 normal volunteers, 18 diver controls, 50 divers with decompression illness (DCI), 34 boxers, 23 schizophrenics and 21 subjects with Alzheimer's disease. RESULTS: The percentages of abnormal cortical voxels for each group were 0.41%, 0.53%, 1.38%, 1.05%, 0.56% and 2.24%, respectively. The percentages of images in each group with at least one lesion of 10 or more connected abnormal voxels and at least 10 lesions of two or more connected voxels, respectively, were 8% and 8% (normal volunteers), 17% and 11% (diver controls), 38% and 38% (divers with DCI), 41% and 29% (boxers), 26% and 13% (schizophrenics) and 90% and 48% (subjects with Alzheimer's disease). This suggests that multiple small lesions are as common as single large lesions for divers with DCI but not for patients with Alzheimer's disease or schizophrenia. Large lesions are located predominantly in the parietal and inferior temporal regions for Alzheimer's disease, in the parietal and occipital regions for divers with DCI and boxers and in the inferior frontal region for schizophrenia. CONCLUSION: It appears that the groups considered here do have different rCBF patterns and that the significance image is a useful way of demonstrating this fact.

Adult↗

PubMed1996

High-resolution random mesh algorithms for creating a probabilistic 3D surface atlas of the human brain.

Striking variations exist, across individuals, in the internal and external geometry of the brain. Such normal variations in the size, orientation, topology, and geometric complexity of cortical and subcortical structures have complicated the problem of quantifying deviations from normal anatomy and of developing standardized neuroanatomical atlases. This paper describes the design, implementation, and results of a technique for creating a three-dimensional (3D) probabilistic surface atlas of the human brain. We have developed, implemented, and tested a new 3D statistical method for assessing structural variations in a data-base of anatomic images. The algorithm enables the internal surface anatomy of new subjects to be analyzed at an extremely local level. The goal was to quantify subtle and distributed patterns of deviation from normal anatomy by automatically generating detailed probability maps of the anatomy of new subjects. Connected systems of parametric meshes were used to model the internal course of the following structures in both hemispheres: the parieto-occipital sulcus, the anterior and posterior rami of the calcarine sulcus, the cingulate and marginal sulci, and the supracallosal sulcus. These sulci penetrate sufficiently deeply into the brain to introduce an obvious topological decomposition of its volume architecture. A family of surface maps was constructed, encoding statistical properties of local anatomical variation within individual sulci. A probability space of random transformations, based on the theory of Gaussian random fields, was developed to reflect the observed variability in stereotaxic space of the connected system of anatomic surfaces. A complete system of probability density functions was computed, yielding confidence limits on surface variation. The ultimate goal of brain mapping is to provide a framework for integrating functional and anatomical data across many subjects and modalities. This task requires precise quantitative knowledge of the variations in geometry and location of intracerebral structures and critical functional interfaces. The surface mapping and probabilistic techniques presented here provide a basis for the generation of anatomical templates and expert diagnostic systems which retain quantitative information on intersubject variations in brain architecture.

Algorithms↗

PubMed1990

The results of radiotherapy for orbital pseudotumor.

Between January 1982 and March 1987, 23 patients (26 orbits) were treated for orbital pseudotumor with radiation therapy at the Department of Radiation Oncology, Hospital of the University of Pennsylvania. The patients were referred for clinical relapse after steroid taper in 70%, no response to steroids in 17%, and no steroid treatment (refused or contraindicated) in 13%. Presenting symptoms/signs included soft tissue swelling in 92% of orbits, pain in 92%, proptosis in 85%, and extraocular muscle dysfunction or ptosis in 69%. Decreased visual acuity was seen in only 19% of orbits. Biopsy was performed in nine patients. Treatment consisted of 2000 cGy in 2 weeks in 10 fractions for all patients. Median follow-up was 41 months, with a mean of 53 months, and a range of 21-92 months. Complete response was documented in 87% of orbits with soft tissue swelling, 82% with proptosis, 78% with extraocular muscle dysfunction, and 75% with pain. Of the five patients with visual acuity defects, three experienced complete recovery. There was no difference in complete response in patients biopsied versus those not biopsied. Overall, 17 orbits have remained in complete orbital response with no further steroid requirement (66%). Three orbits suffered local relapse at some point following radiation therapy and were retreated with steroids. These three orbits had durable local control off steroids at last follow-up (11%). Therefore, 77% of orbits attained durable local control and were steroid independent with radiation therapy alone or radiation therapy followed by steroids for relapse. Only one patient developed systemic lymphoma with follow-up. No pretreatment clinical factor reached statistical significance with respect to prognosis following radiation therapy at the less than or equal to .05 level. There were no significant acute or chronic side effects secondary to treatment. Steroids should continue to be first line treatment for orbital pseudotumor, but radiation therapy has a well-defined role in cases of steroid failure or in patients unable to tolerate steroid therapy.

Adolescent↗

PubMed2001

Quantification of F-18 FDG PET images in temporal lobe epilepsy patients using probabilistic brain atlas.

A probabilistic atlas of the human brain (Statistical Probabilistic Anatomical Maps: SPAM) was developed by the international consortium for brain mapping (ICBM). It is a good frame for calculating volume of interest (VOI) in many fields of brain images. After calculating the counts in VOI using the product of probability of SPAM images and counts in FDG images, asymmetric indices (AI) were calculated and used for finding epileptogenic zones in mesial temporal lobe epilepsy (mTLE). FDG PET images from 18 surgically confirmed mTLE patients and 22 age-matched controls were spatially normalized to the average brain MRI template of ICBM. Counts from normalized PET images were multiplied with the probability of 12 VOIs from SPAM images in both temporal lobes. Finally AI were calculated on each pair of VOIs, and compared with visual assessment. If AI of mTLE patients were not within 2.9 standard deviation from those of normal control group (P < 0.008; Bonferroni correction for P < 0.05), epileptogenic zones were considered to be found successfully. The counts of VOIs in the normal control group were symmetric (AI < 4.3%, paired t test P > 0.05) except for those of the inferior temporal gyrus (P < 0.001). By AIs in six pairs of VOIs, PET in mTLE had deficit on one side (P < 0.05). Lateralization was correct in only 14/18 of patients by AI, but 17/18 were consistent with visual inspection. In three patients with normal AI, PET images were symmetric on visual inspection. The asymmetric indices obtained by taking the product of the statistical probability anatomical map and FDG PET, correlated well with visual assessment in mTLE patients. SPAM is useful for the quantification of VOIs in functional images.

Adult↗