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Background: Cephalohematomas (CH) are benign neonatal fluid collections that arise between the periosteum and skull due to birth trauma, and usually resolve spontaneously without intervention. CH may rarely become infected. Case Description: The authors report a case of sterile CH requiring surgical evacuation in a persistently febrile neonate treated with intravenous (IV) antibiotics for Escherichia coli urosepsis. Diagnostic tap of the CH yielded no pathogens, but given the persistence of fevers, surgical evacuation was performed. The patient demonstrated clinical improvement postoperatively. Conclusion: A systematic review of literature was conducted through a MEDLINE search using the keyword “cephalohematoma.” Articles were screened for cases of infected CH and their subsequent management. Clinicopathological characteristics and outcomes of the present case were reviewed and compared to those in the literature. Infected CH were reported in 25 articles describing 58 patients. Common pathogens included E. coli and Staphylococcal species. Treatment included a course of IV antibiotics (10 days–6 weeks) and often included percutaneous aspiration (n = 47) for diagnostic and therapeutic purposes. Surgical evacuation was performed in 23 cases. To the authors’ knowledge, the present case is the first documented report in which evacuation of a culture-negative CH resulted in resolution of the patient’s clinical symptoms of sepsis that persisted despite appropriate antibiotic treatment. This suggests that patients with CH should be evaluated through diagnostic tap of the collection if there are signs of local or persistent systemic infection. Surgical evacuation may be indicated if percutaneous aspiration does not result in clinical improvement.

BACKGROUND Hypertrophic cranial pachymeningitis is a rare inflammatory disorder characterized by thickening of the dura mater and multiple cranial neuropathies. Although an infectious etiology may be present, often no specific cause is discovered. OBSERVATIONS The authors described a 71-year-old man with progressive right eye vision loss, ptosis, and complete ophthalmoplegia with imaging findings suggestive of hypertrophic cranial pachymeningitis. Extensive studies, including cerebrospinal fluid studies, showed negative results. Blood serum, cell-free evaluation, and paraffin-embedded dural tissue testing had positive results for Pseudomonas aeruginosa, which allowed treatment tailored to the organism and a salutary clinical outcome. LESSONS The constellation of neurological and radiological findings may make a diagnosis difficult in an inflammatory setting. The most precise methodology for establishing a diagnosis involves sampling the dura and testing it for infectious pathology. However, if results are inconclusive, further cell-free serum sampling with next-generation sequencing is a viable option for identifying pathogens with infectious concerns. This case highlighted the importance of multimodality studies for identifying a targetable pathogen.

Background Parkinson’s Disease (PD) is a clinically diagnosed neurodegenerative disorder that affects both motor and non-motor neural circuits. Speech deterioration (hypokinetic dysarthria) is a common symptom, which often presents early in the disease course. Machine learning can help movement disorders specialists improve their diagnostic accuracy using non-invasive and inexpensive voice recordings. Method We used “Parkinson Dataset with Replicated Acoustic Features Data Set” from the UCI-Machine Learning repository. The dataset included 44 speech-test based acoustic features from patients with PD and controls. We analyzed the data using various machine learning algorithms including Light and Extreme Gradient Boosting, Random Forest, Support Vector Machines, K-nearest neighborhood, Least Absolute Shrinkage and Selection Operator Regression, as well as logistic regression. We also implemented a variable importance analysis to identify important variables classifying patients with PD. Results The cohort included a total of 80 subjects: 40 patients with PD (55% men) and 40 controls (67.5% men). Disease duration was 5 years or less for all subjects, with a mean Unified Parkinson’s Disease Rating Scale (UPDRS) score of 19.6 (SD 8.1), and none were taking PD medication. The mean age for PD subjects and controls was 69.6 (SD 7.8) and 66.4 (SD 8.4), respectively. Our best-performing model used Light Gradient Boosting to provide an AUC of 0.951 with 95% confidence interval 0.946–0.955 in 4-fold cross validation using only seven acoustic features. Conclusions Machine learning can accurately detect Parkinson’s disease using an inexpensive and non-invasive voice recording. Light Gradient Boosting outperformed other machine learning algorithms. Such approaches could be used to inexpensively screen large patient populations for Parkinson’s disease.

BACKGROUND: Conditions requiring cervical decompression and stabilization are commonly treated using anterior cervical discectomy and fusion using an anterior cage-plate construct. Anterior zero profile integrated cages are an alternative to a cage-plate construct, but literature suggests they may result in less motion reduction. Interfacet cages may improve integrated cage stability. This study evaluated the motion reduction of integrated cages with and without supplemental interfacet fixation. Motion reduction of integrated cages were also compared to published cage-plate results. METHODS: Seven cadaveric (C2-T1) spines were tested in flexion-extension, lateral bending, and rotation. Specimens were tested: 1) intact, 2) C6-C7 integrated cage, 3) C6-C7 integrated cage + interfacet cages, 4) additional integrated cages at C3-C4 and C4-C5, 5) C3-C4, C4-C5 and C6-C7 integrated cages + interfacet cages. Motion, lordosis, disc and neuroforaminal height were assessed. FINDINGS: Integrated cage at C6-C7 decreased flexion-extension by 37% (P=0.06) and C3-C5 by 54% (P

Background : Parkinson’s Disease (PD) is a clinically diagnosed neurodegenerative disorder that affects both motor and non-motor neural circuits. Speech deterioration (hypokinetic dysarthria) is a common symptom, which often presents early in the disease course. Machine learning can help movement disorders specialists improve their diagnostic accuracy using non-invasive and inexpensive voice recordings. Method : We used “Parkinson Dataset with Replicated Acoustic Features Data Set” from the UCI-Machine Learning repository. The dataset included 45 features including sex and 44 speech test based acoustic features from 40 patients with Parkinson’s disease and 40 controls. We analyzed the data using various machine learning algorithms including tree-based ensemble approaches such as random forest and extreme gradient boosting. We also implemented a variable importance analysis to identify important variables classifying patients with PD. Results : The cohort included total of 80 subjects; 40 patients with PD (55% men) and 40 controls (67.5% men). PD patients showed at least two of the three symptoms; resting tremor, bradykinesia, or rigidity. All patients were over 50 years old and the mean age for PD subjects and controls were 69.6 (SD 7.8) and 66.4 (SD 8.4), respectively. Our final model provided an AUC of 0.940 with 95% confidence interval 0.935-0.945in 4-folds cross validation using only six acoustic features including Delta3 (Run2), Delta0 (Run 3), MFCC4 (Run 2), Delta10 (Run 2/Run 3), MFCC10 (Run 2) and Jitter_Rap (Run 1/Run 2). Conclusions : Machine learning can accurately detect Parkinson’s disease using an inexpensive and non-invasive voice recording. Such technologies can be deployed into smartphones for screening of large patient populations for Parkinson’s disease.

BACKGROUND CONTEXT Elderly patients are increasingly meeting the indications for spinal fusion and are more likely to have suboptimal bone quality. Patients with suboptimal bone quality who have undergone posterior cervical fusion have increased risk of fixation failure of up to 5.4% and may require stronger forms of fixation. Adding supplemental fixation to lateral mass screws (LMS) can increase fixation as measured by pullout strength. PURPOSE This work addresses the question: can supplemental screw fixation of lateral mass screws improve pullout strength? STUDY DESIGN/SETTING Biomechanical cadaveric study. PATIENT SAMPLE Fifteen C3-C6 vertebral bodies and 15 additional motion segments (C3-C4 or C5-C6) (age: 49-67). OUTCOME MEASURES Lateral mass screw construct peak pullout strength. METHODS All specimens were CT scanned with a phantom to obtain bone mineral density (BMD). The individual vertebral bodies and the cranial body of the motion segments were implanted with bilateral lateral mass screws. Supplemental fixation was added on one side of the vertebral body using two 2.4mm diameter unicortical screws (length 8-12mm). One side of the cranial vertebral body of the motion segments was supplemented with a single 2.4mm diameter transfacet tricortical screw (length 12-16mm). Screw constructs were subjected to posterior pullout coincident with the axis of the lateral mass screw at a rate of 5mm/min until failure. RESULTS A paired comparison was made of the peak pullout force of the LMS alone and LMS with supplemental fixation. Analysis was also made comparing BMD and pullout force.In the vertebral bodies with two supplemental unicortical screws, pullout force was significantly higher in the supplemented screw side. The average pullout force was 48.2% higher with supplemental screws (865±213N vs 637±206N; p=0.0038). There was moderate correlation between pullout force and bone mineral density for both the supplemented and LMS alone (correlation coefficients of 0.34 and 0.45 respectively). In the motion segments, peak pullout force was significantly higher in the side supplemented with a tricortical transfacet screw. The pullout force was 25.9% higher with supplemental transfacet screw fixation (1055±521N vs 912±508N; p=0.047). The pullout strength of the LMS with transfacet fixation was highly correlated with BMD (correlation coefficient of 0.71) while the LMS pullout strength was moderately correlated with BMD (correlation coefficient of 0.64). CONCLUSIONS Our data confirms the hypotheses that the pullout strength of C3-C6 LMS fixation using LMS supplemented with two unicortical screws or LMS supplemented with one-tricortical transfacet screw is superior to LMS fixation alone. FDA DEVICE/DRUG STATUS Cervical Fusion System (Approved for this indication)

BACKGROUND CONTEXT The use of cervical disc arthroplasty (CDA) adjacent to an anterior cervical decompression and fusion (ACDF), a hybrid construct, is an attractive alternative to a multilevel cervical fusion operation. Consider a clinical scenario where a patient with a prior fusion at C6-C7 develops new radiculopathy and/or myelopathy at C5-C6. A surgeon considers a CDA at C5-C6, proximal to an existing C6-C7 ACDF, in hopes of reducing the risk of adjacent segment disease at C4-C5. Another clinical scenario is in the presence of two symptomatic adjacent cervical segments, a surgeon may consider fusing the segment with more severe spondylotic changes such as severe disc collapse and facet arthropathy while performing CDA at the adjacent, more mobile segment. While numerous studies have demonstrated excellent clinical outcomes of primary cervical disc replacement surgery, many questions regarding the biomechanics of CDA in a hybrid construct remain unanswered. PURPOSE (1) How is disc prosthesis motion response influenced by the presence of a fusion proximal or distal to the prosthesis? and (2) How does the number of fused levels in the hybrid construct affect the prosthesis motion? STUDY DESIGN/SETTING Biomechanical study using human cadaveric cervical spines. PATIENT SAMPLE Human cervical spine specimens (C2-T1, N=10, 46±16 years). OUTCOME MEASURES Segmental flexion-extension range of motion (ROM). METHODS Specimens were divided into two equal groups based on age, gender distribution, and preoperative mobility. Segmental motions were assessed under flexion and extension moments of 1.5 Newton-meters. In Group I, the arthroplasty was proximal to one- and two-level ACDF, while in Group 2, the arthroplasty was distal to one- and two-level ACDF. ACDF was performed using a PEEK cage and anterior plate and CDA was performed using the M6-C cervical disc prosthesis (Orthofix Medical, Inc). Within group comparisons were made using a repeated-measures ANOVA and paired-t test, whereas across group comparisons used 2-sample t-test. RESULTS Segment level of implantation: 20 segments underwent CDA. Ten discs were implanted at C4-C5, 5 at C5-C6, and 5 at C6-C7. The mean segmental ROM after CDA was 9.2±4.2 degrees. Segmental level of implantation did not influence the ROM (C4-C5: 8.6±3.7; C5-C6: 9.4±4.1; C6-C7: 10.0±6.1; p>0.7). Number of fused levels in the hybrid construct: The number of fused segments in the hybrid construct did not influence the ROM after CDA (1-level: 9.7±4.6 vs 2-level: 9.9±4.4; p=0.9). CDA proximal vs distal to fusion: CDA above a 1-level ACDF had ROM similar to CDA below a 1-level ACDF (9.4±4.1 degrees vs 10.0±6.1; p=0.76). This result also held for a prosthesis implanted above versus below a 2-level ACDF (9.9±4.6 vs 9.8±5.2; p=1.0). CDA in hybrid construct compared to intact: CDA in a hybrid construct had ROM similar to the ROM of the corresponding segment in the intact spine. This result held true for all hybrid constructs studied regardless of location of prosthesis above or below a fusion, and the number of fused levels. CONCLUSIONS This study simulated a scenario where the patient experiences the same moments before and after surgery. Some authors suggest patients maintain similar ROM before and after surgery. Likely, actual in vivo loading reflects a combination of the two approaches. Results of this study suggest that disc arthroplasty performed adjacent to a 1- or 2-level cervical fusion is likely to maintain the same degree of motion as a primary arthroplasty. These findings provide a cadaveric basis for future in vivo studies to validate these results. FDA DEVICE/DRUG STATUS M6C artificial cervical disc, Orthofix, Inc (Not approved for this indication)

INTRODUCTION Morphologic features of computed tomography (CT) scans of the brain can be used to estimate intracranial pressure (ICP) via an image-processing algorithm. Clinically, such estimations can be used to prognosticate outcomes and avoid placement of invasive intracranial monitors in certain patients with severe traumatic brain injury. Features on a CT scan that may correlate with measurements of low ICP are sought. METHODS A measure is proposed that is a function of the distribution of cerebrospinal fluid (CSF) in and around the brain. In our method, we present an algorithm that semiautomatically segments brain parenchyma from CSF, and apply standard image processing calculations. The ratio of CSF volume to the size of the intracranial vault (ICV) or volume inside the skull, csf(v) /icv(v) is calculated and then plotted against the actual recorded ICP, yielding a relationship between the image features and ICP. RESULTS We analyzed a total of 45 scans from 20 patients with severe traumatic brain injury (TBI). We showed that a ratio csf(v)/icv(v) > .034 correlates with an ICP < 20 mmHg (P = .0046). For csf(v)/icv(v) ≤ .034, a distinction between low and high ICP cannot be effectively estimated by this univariate measure. CONCLUSION This method permits a noninvasive means of identifying patients who are low risk for having elevated ICP; by following Brain Trauma Foundation guidelines strictly such a patient may be subjected to an unnecessary, invasive procedure. This work is a promising pilot study that will need to be analyzed for a larger population.

We seek a methodological approach to assess circadian processes in subjects who have recently experienced traumatic brain injury, using regularly gathered intracranial temperature data. The health effects of circadian regulation are profound, yet assessments of circadian processes are often infeasible in the neurotrauma intensive care unit (ICU). We assess circadian periodicity through the energy density spectrum, applying model-based and model-free methods: an extended Kalman filter (using the Kronauer model) in conjunction with a fast Fourier transform (FFT), and the Lomb–Scargle periodogram, respectively. We compute the change in relative energy in a narrow band of the spectrum, corresponding to a period of 23-25 h, over the first 48 and last 48 h of each subject's stay in the ICU. The change in relative energy in the spectrum increases in subjects with Good outcomes, and decreases in subjects with Poor outcomes, with statistical significance. For those subjects with Good outcome, we show evidence of regulation in circadian phase using an adaptive notch filter.

Aunque se considera que los aneurismas saculares de la aorta abdominal (AAA) son mas propensos a la rotura que los fusiformes, las tentativas para validar esta observacion han sido limitadas debido a la imposibilidad de definir cuantitativamente la morfologia tridimensional de la aorta. Un modelo cuantitativo de su estructura geometrica podria distinguir entre clases de morfologias y, en ultimo termino, ser util para identificar los aneurismas con riesgo de rotura. Se generaron datos tridimensionales de la superficie luminal de AAA a partir de imagenes tomograficas computarizadas (TC) de 15 pacientes con aneurismas de pequeno tamano (≤ 5,5 cm diametro transverso maximo). Se utilizo una linea central para producir una clasificacion de la morfologia basada en la proyeccion ortografica de la linea central alrededor de su eje central. Se cuantificaron la extension y direccion de las desviaciones individuales como areas en el plano de proyeccion para crear una clasificacion de la morfologia. Para verificar las diferentes clases de forma se uso un analisis de agrupacion jerarquica. Se calculo un indice de tortuosidad y se clasifico en diferentes clases desde mimima a maxima. La existencia de trombomural podria modificar el indice de tortuosidad o su clasificacion morfologica. En diversos pacientes con TC seriadas, el indice de tortuosidad cambio con el tiempo y se correlaciono con la rotura. En tres de ellos; en los que su AAA evoluciono hacia la rotura, la tortuosidad media aumento un 29% mientras que el diametro transverso medio aumento un 3,3%. Los AAA en expansion desarrollan morfologias especificas y cuantificables que pueden expresarse como un indice de tortuosidad cuantitativa que puede ser congruente con su historia natural. Las caracteristicas tridimensionales de este modelo morfologico proporcionan informacion complementaria a la simple medicion del diametro transverso maximo que puede resultar clinicamente adecuado. Se requieren estudios de mayor tamano para correlacionar el indice de tortuosidad con los modelos de elemento finito y la capacidad para predecir la rotura del aneurisma.

Alors que les anevrysmes de l'aorte abdominale (AAA) sacciformes sont consideres comme davantage enclins a la rupture que les anevrysmes fusiformes, les tentatives pour valider cette observation ont ete limitees par l'incapacite de definir quantitativement la forme tridimensionnelle d'une aorte. Un modele quantitatif tridimensionnel de forme pourrait permettre de distinguer les differentes formes et etre utile pour identifier les anevrysmes a risque de rupture. Les donnees tridimensionnelles d'AAA ont ete generees a partir d'images tomodensitometriques (TDM) chez 15 malades ayant des petits anevrysmes (≤ 5,5 cm de diametre transversal maximum). La ligne centrale a ete utilisee pour construire une classification morphologique basee sur la projection orthogonale de la ligne centrale suivant son axe. L'etendue et la direction des deviations individuelles ont ete quantifiees comme des zones du plan de projection pour creer une classification morphologique. Une analyse en groupes hierarchiques a ete utilisee pour verifier les differentes classes de forme. Un index de tortuosite a ete calcule en fonction de la projection de la ligne centrale. La forme de l'AAA a ete calculee comme un index de tortuosite et classee en differentes classes de tortuosite tridimensionnelle minime ou importante. La presence d'un thrombus pouvait modifier l'index de tortuosite ou la classification morphologique de l'anevrysme. Chez plusieurs malades ayant des TDM repetees, l'index de tortuosite a change au cours du temps et a ete correle a la rupture. Chez trois AAA qui se sont rompus, la tortuosite moyenne a augmente de 29 % alors que le diametre transversal moyen augmentait de 3,3 %. Les AAA en expansion developpent des formes specifiques quantifiables qui peuvent etre exprimees sous la forme d'un index quantitatif de tortuosite qui peut etre interessant pour etudier leur histoire naturelle. Les caracteristiques tridimensionnelles de ce modele de forme fournissent un element nouveau et sans doute interessant cliniquement par rapport au diametre maximum transversal. Des etudes plus larges sont necessaires pour correler l'index de tortuosite avec les modeles proposes et la capacite de prevenir la rupture d'anevrysme.

Morphologic features of computed tomography (CT) scans of the brain can be used to estimate intracranial pressure (ICP) via an image-processing algorithm. Clinically, such estimations can be used to prognosticate outcomes and avoid placement of invasive intracranial monitors in certain patients with severe traumatic brain injury. Features on a CT scan that may correlate with measurements of low ICP are sought.A measure is proposed that is a function of the distribution of cerebrospinal fluid (CSF) in and around the brain. In our method, we present an algorithm that semiautomatically segments brain parenchyma from CSF, and apply standard image processing calculations. The ratio of CSF volume to the size of the intracranial vault (ICV) or volume inside the skull, csf(v) /icv(v) is calculated and then plotted against the actual recorded ICP, yielding a relationship between the image features and ICP.We analyzed a total of 45 scans from 20 patients with severe traumatic brain injury (TBI). We showed that a ratio csf(v)/icv(v).034 correlates with an ICP20 mmHg (P = .0046). For csf(v)/icv(v) ≤ .034, a distinction between low and high ICP cannot be effectively estimated by this univariate measure.This method permits a noninvasive means of identifying patients who are low risk for having elevated ICP; by following Brain Trauma Foundation guidelines strictly such a patient may be subjected to an unnecessary, invasive procedure. This work is a promising pilot study that will need to be analyzed for a larger population.

Normal blood flow in the brain as a response to pressure fluctuations is commonly referred to as cerebral autoregulation. Linear, nonparametric models of cerebral autoregulation were estimated for 77 human subjects afflicted with brain injury, with mean arterial pressure used as input, and invasively measured regional cerebral blood flow used as output. The data were continuously monitored from the beginning of subject hospital stay. Mean transfer function gain as a function of frequency was calculated for each subject over a limited time window spanning 48 h, starting postsurgery. The mean transfer function gain of the cerebral autoregulation model provided a highly accurate, statistically significant, assessment of patient outcome. Subjects were accurately grouped by outcome, with a high significance (p

Historically, determination of the critical cerebral perfusion pressure (CPP) was done in animals by a progressive lowering of arterial pressure yielding a nominal critical CPP of 60 mmHg. Subsequently, it was shown that if the CPP was decreased by increasing intracranial pressure (ICP), critical CPP fell to 30 mmHg. This discrepancy was unexplained. We recently provided evidence that the decrease in critical CPP was due to microvascular shunting resulting in maintained cerebral blood flow (CBF) at a lower CPP. We demonstrated by a progressive increase in ICP in rats using two-photon laser scanning microscopy (2PLSM) that the transition from capillary to microvascular shunt flow is a pathological process. We surmise that the loss of CBF autoregulation revealed by decreasing arterial pressure occurs by dilation of normal cerebral blood vessels whereas that which occurs by increasing ICP is due to microvascular shunting. Our observations indicate that the loss of CBF autoregulation we observed in brain injured patients that changes on an hourly or daily basis reflects an important pathophysiological process impacting on outcome that remains to be determined.

A fundamental open problem in computer vision—determining pose and correspondence between two sets of points in space—is solved with a novel, fast, robust and easily implementable algorithm. The technique works on noisy 2D or 3D point sets that may be of unequal sizes and may differ by non-rigid transformations. Using a combination of optimization techniques such as deterministic annealing and the softassign , which have recently emerged out of the recurrent neural network/statistical physics framework, analog objective functions describing the problems are minimized. Over thirty thousand experiments, on randomly generated points sets with varying amounts of noise and missing and spurious points, and on hand-written character sets demonstrate the robustness of the algorithm.

Hyperemia in the infarcted brain has been ­suggested for years by “red veins” reported by neurosurgeons, shunt peaks in radioactive blood flow clearance curves, and quantitative cerebral blood flow using stable xenon CT. Histological characterization of infarcted brain revealed capillary rarefaction with prominent microvascular shunts (MVS). Despite abundant histological evidence, the presence of cerebrovascular shunts have been largely ignored, perhaps because of a lack of physiological evidence demonstrating the transition from capillary flow to MVS flow. Our studies have shown that high intracranial pressure induces a transition from capillary to microvascular shunt flow resulting in cerebral hypoperfusion, tissue hypoxia and brain edema, which could be delayed by increasing cerebral perfusion pressure. The transition from capillary to microvascular shunt flow provides for the first time a physiological basis for evaluating the optimal cerebral perfusion pressure with increased intracranial pressure. It also provides a physiological basis for evaluating the effectiveness of various drugs and therapies in reducing intracranial pressure and the development of brain edema and tissue hypoxia after brain injury and ischemia. In summary, the clear-cut demonstration of the transition from capillary to MVS flow provides an important method for evaluating various therapies for the treatment of brain edema and loss of autoregulation.

Objective The authors report a case of a large intracerebellar hemorrhage that occurred in a professional musician while playing the trumpet. This is the first report of such a complication. Clinical presentation A 60-year-old man presented with severe occipital headache accompanied by nausea, vomiting, and dizziness that occurred while he was practicing the trumpet. On presentation, he was hypertensive with a systolic blood pressure of 255 mmHg and was found to have a large left cerebellar hemorrhage. Intervention Magnetic resonance imaging and magnetic resonance angiography were performed but revealed no tumor or vascular abnormality. The patient was initially stable but, despite maximal medical therapy, deteriorated and was taken to the operating room for suboccipital craniectomy and evacuation of the hematoma. Conclusion This patient likely had chronic hypertension; however, the transient increase in systolic blood pressure associated with intensive trumpet playing and the Valsalva maneuver may have contributed to his risk of hemorrhage. We suggest that hypertensive screening and therapy may be especially important in this population and emphasize the importance for neurosurgeons to understand the physiology involved in the Valsalva maneuver.

While saccular abdominal aortic aneurysms (AAAs) are thought to be more prone to rupture than fusiform aneurysms, attempts to validate this observation have been limited by the inability to quantitatively define the three-dimensional shape of an aorta. A quantitative three-dimensional shape model may distinguish among shape classes and ultimately be useful in identifying aneurysms at risk for rupture. Three-dimensional luminal surface data of AAAs were generated from computed tomographic (CT) images of 15 patients with small aneurysms (or =5.5 cm maximal transverse diameter). The centerline was used to construct a shape classification based upon the orthographic projection of the centerline about its central axis. The extent and direction of the individual deviations were quantified as areas on the plane of projection to create a shape classification. Hierarchical cluster analysis was used to verify distinct shape classes. A tortuosity index was calculated as a function of the centerline projection. AAA shape was calculated as a tortuosity index and classified into distinct classes of minimal or increased three-dimensional tortuosity. Thrombus could change the tortuosity index or shape classification of an aneurysm. In several patients with serial CT scans, the tortuosity index changed over time and was correlated with rupture; in three AAAs that ruptured the mean tortuosity increased 29% whereas the mean transverse diameter increased 3.3%. Expanding AAAs develop specific, quantifiable shapes that can be expressed as a quantitative tortuosity index that may be relevant to their natural history. The three-dimensional features of this shape model provide a novel and potentially clinically relevant adjunct to maximal transverse diameter. Larger studies are needed to correlate the tortuosity index with finite element models and the ability to predict aneurysm rupture.

We present a novel method for the geometric alignment of autoradiographs of the brain. The method is based on finding the spatial mapping and the one-to-one correspondences (or homologies) between point features extracted from the images and rejecting non-homologies as outliers. In this way, we attempt to account for the local, natural and artifactual differences between the autoradiograph slices. We have used the resulting automated algorithm on a set of left prefrontal cortex autoradiograph slices, specifically demonstrated its ability to perform point outlier rejection, validated its robustness property using synthetically generated spatial mappings and provided an anecdotal visual comparison with the well-known iterated closest-point (ICP) algorithm. Visualization of a stack of aligned left prefrontal cortex autoradiograph slices is also provided.

Neuroimaging of the human brain has opened the way for a genuine understanding of human cognition; but the circuitry and cellular basis of the extraordinary information processing capacity of humans can be addressed only in experimental animals such as nonhuman primates by using the 2-DG autoradiographic method. This method requires sacrifice of the animal and sectioning of the brain into serial sections followed by production of autoradiographs of individual brain sections which are not in register. We have developed a new automated alignment method to reconstitute the autoradiographs. Our alignment method automatically finds the 2-D spatial mapping and the homologies between the slices and robustly accounts for the natural and artifactual differences by applying the powerful mechanism of outlier rejection adapted from the robust statistics literature.

A 3D computational fluid dynamics model of the human carotid bifurcation has been created to explore plaque excavation and plaque rupture. The model considers different degrees of atherosclerotic stenosis, the form of which is determined using computerised tomography scans of a patient with moderate plaque stenosis. The results suggest that 70% stenosis will diminish blood flow to the brain from 245 ml/min to 71 ml/min. Pressure in the 50% stenosis model is increased by only 3.3%, while pressure in the 70% and 80% stenosis models are increased by 8.8% and 15.4%, respectively. Starting at 30% stenosis, each increase of 10% stenosis increases the peak wall shear stress value by a factor of two. Severely elevated magnitudes in the product of the pressure and the wall shear stress gradient were found on the upstream face of the stenosis. In specific cases, these peaks can be correlated to excavation points observed clinically.

The sensitivity of sestamibi scanning techniques used for preoperative localization in primary hyperparathyroidism is a function of the parameters of image acquisition and processing.Criterion standard vs optimized technique.Tertiary referral center.One hundred forty-eight consecutive patients with primary hyperthyroidism were analyzed. Under the initial protocol, 97 patients underwent a preexisting standard sestamibi--single-photon emission computed tomographic scan and surgical exploration. The scanning technique was modified and in the revised protocol, 51 patients underwent imaging and surgical exploration.Image acquisition and processing revisions as follows: patient positioning standardized, collimator resolution adjusted, radioactive tracer delay extended, visualization field broadened, data extraction refined, and image processing filter modified.concordance among the scan and operative localization, lateralization, and cure rate.Initial protocol: 97 patients underwent surgery for primary hyperthyroidism with the initial sestamibi design. Eighty-one patients (83%) had a positive result, that is, at least 1 gland was identified; 77 patients (79%) had correct lateralization; and 49 patients (52%) had precise localization. Revised protocol: 51 patients underwent imaging under the optimized protocol. Forty-nine patients (96) had a positive result; 47 patients (92%) had correct lateralization; and 36 patients (70%) had precise localization. These improvements were significant, with P.05 for localization and P.01 for lateralization. Cure rates were 96% in both groups, confirmed by laboratory and pathologic findings.Sestamibi optimization in primary hyperparathyroidism can improve scan sensitivity. This may permit a focused minimally invasive operation.