Assessing the reproducibility of CBCT-derived radiomics features using a novel three-dimensional printed phantom.

Purpose: Radiomics modeling is an exciting avenue for enhancing clinical decision making and personalized treatment. Radiation oncology patients often undergo routine imaging for position verification, particularly using LINAC-mounted cone beam computed tomography (CBCT). The wealth of imaging data collected in modern radiation therapy presents an ideal use case for radiomics modeling.

Multitask Learning Based Three-Dimensional Striatal Segmentation of MRI: fMRI and PET Objective Assessments.

Background: Recent studies have established a clear topographical and functional organization of projections to and from complex subdivisions of the striatum. Manual segmentation of these functional subdivisions is labor-intensive and time-consuming, and automated methods are not as reliable as manual segmentation.

Purpose: To utilize multitask learning (MTL) as a method to segment subregions of the striatum consisting of pre-commissural putamen (prePU), pre-commissural caudate (preCA), post-commissural putamen (postPU), post-commissural caudate (postCA), and ventral striatum (VST).

Full-count PET recovery from low-count image using a dilated convolutional neural network.

Purpose: Positron emission tomography (PET) is an essential technique in many clinical applications that allows for quantitative imaging at the molecular level. This study aims to develop a denoising method using a novel dilated convolutional neural network (CNN) to recover full-count images from low-count images.

Methods: We adopted similar hierarchical structures as the conventional U-Net and incorporated dilated kernels in each convolution to allow the network to observe larger, more robust features within the image without the requirement of downsampling and upsampling internal representations.

The importance of identifying functional Val158Met polymorphism in catechol-O- Methyltransferase when assessing MRI-based volumetric measurements in major depressive disorder.

Many studies have shown volumetric differences in the hippocampus between COMT gene polymorphisms and other studies have shown differences between depressed patients and controls; yet, few studies have been completed to identify the volumetric differences when taking both factors into consideration. Using voxel-based morphology (VBM) we investigated, in major depressive disorder (MDD) patients and healthy controls, the relationship between COMT gene polymorphism and volumetric abnormalities. Data from 60 MDD patients and 25 healthy controls were included in this study.

Task-based assessment of a convolutional neural network for segmenting breast lesions for radiomic analysis.

Purpose: Radiomics allows for powerful data-mining and feature extraction techniques to guide clinical decision making. Image segmentation is a necessary step in such pipelines and different techniques can significantly affect results. We demonstrate that a convolutional neural network (CNN) segmentation method performs comparably to expert manual segmentations in an established radiomics pipeline.

Merging Orthovoltage X-Ray Minibeams spare the proximal tissues while producing a solid beam at the target.

Conventional radiation therapy of brain tumors often produces cognitive deficits, particularly in children. We investigated the potential efficacy of merging Orthovoltage X-ray Minibeams (OXM). It segments the beam into an array of parallel, thin (~0.

Prediction of Abnormal Bone Density and Osteoporosis From Lumbar Spine MR Using Modified Dixon Quant in 257 Subjects With Quantitative Computed Tomography as Reference.

Background: Bone marrow fat increases when bone mass decreases, which could be attributed to the fact that adipogenesis competes with osteogenesis. Bone marrow fat has the potential to predict abnormal bone density and osteoporosis.

Purpose: To investigate the predictive value of using vertebral bone marrow fat fraction(BMFF) obtained from modified Dixon(mDixon) Quant in the determination of abnormal bone density and osteoporosis.

Preoperative prediction of sentinel lymph node metastasis in breast cancer by radiomic signatures from dynamic contrast-enhanced MRI.

Background: Sentinel lymph node (SLN) status is an important prognostic factor for patients with breast cancer, which is currently determined in clinical practice by invasive SLN biopsy.

Purpose: To noninvasively predict SLN metastasis in breast cancer using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) intra- and peritumoral radiomics features combined with or without clinicopathologic characteristics of the primary tumor.

Study Type: Retrospective.

Synthesis of Patient-Specific Transmission Data for PET Attenuation Correction for PET/MRI Neuroimaging Using a Convolutional Neural Network.

Attenuation correction is a notable challenge associated with simultaneous PET/MRI, particularly in neuroimaging, where sharp boundaries between air and bone volumes exist. This challenge leads to concerns about the visual and, more specifically, quantitative accuracy of PET reconstructions for data obtained with PET/MRI. Recently developed techniques can synthesize attenuation maps using only MRI data and are likely adequate for clinical use; however, little work has been conducted to assess their suitability for the dynamic PET studies frequently used in research to derive physiologic information such as the binding potential of neuroreceptors in a region.

Breast lesion characterization using whole-lesion histogram analysis with stretched-exponential diffusion model.

Background: Diffusion-weighted imaging (DWI) has been studied in breast imaging and can provide more information about diffusion, perfusion and other physiological interests than standard pulse sequences. The stretched-exponential model has previously been shown to be more reliable than conventional DWI techniques, but different diagnostic sensitivities were found from study to study.

Purpose: This work investigated the characteristics of whole-lesion histogram parameters derived from the stretched-exponential diffusion model for benign and malignant breast lesions, compared them with conventional apparent diffusion coefficient (ADC), and further determined which histogram metrics can be best used to differentiate malignant from benign lesions.

Diffusion Entropy: A Potential Neuroimaging Biomarker of Bipolar Disorder in the Temporal Pole.

Despite much research, bipolar depression remains poorly understood, with no clinically useful biomarkers for its diagnosis. The paralimbic system has become a target for biomarker research, with paralimbic structural connectivity commonly reported to distinguish bipolar patients from controls in tractography-based diffusion MRI studies, despite inconsistent findings in voxel-based studies. The purpose of this analysis was to validate existing findings with traditional diffusion MRI metrics and investigate the utility of a novel diffusion MRI metric, entropy of diffusion, in the search for bipolar depression biomarkers.

Genetic covariation in low alcohol-sensitive and high alcohol-sensitive selected lines of rats: behavioral and electrophysiological sensitivities to the depressant effects of ethanol and the development of acute neuronal tolerance to ethanol in situ at generation eight.

Phenotypic differences in behavioral and initial neuronal sensitivities to acute ethanol (EtOH) administration were examined and compared among replicate lines of rats, which were selectively bred for low and high EtOH sensitivity. The eighth generation of HAS (EtOH-sensitive) and LAS (EtOH-insensitive) rats were significantly different in terms of sensitivity both to EtOH-induced loss of righting response (sleep time) and to EtOH-induced depressions of cerebellar Purkinje neuron firing rates. This study provides the first evidence for a significant correlation between behavioral and electrophysiological EtOH sensitivities among individual animals and between replicate selected rodent lines.

Selective breeding of rats differing in sensitivity to the effects of acute ethanol administration.

Selective breeding of rats for sensitivity to the anesthetic effects of ethanol is being carried out with rats derived from the genetically heterogeneous N/Nih stock. Thirteen generations of within family selection have been achieved with replicate high (HAS), low (LAS) and control alcohol sensitive (CAS) lines. Significant separation between lines on sleep time and blood ethanol concentration (BEC) at awakening following ethanol administration has been achieved.

gamma-Aminobutyric acid-activated chloride channels: relationship to genetic differences in ethanol sensitivity.

We demonstrated recently that low concentrations of ethanol enhanced the muscimol-stimulated chloride influx in cerebellar membranes from long sleep (LS-ethanol sensitive) mice, but had no effect on membranes from short sleep (SS-ethanol resistant) mice. The LS and SS were selected from a heterogeneous stock (HS) of mice for differential sensitivity to the hypnotic effects of ethanol as measured by the duration of the loss of the righting reflex (sleep time). In the present study, we tested 100 HS for ethanol sleep time.

Genetic risk for recombinant 8 syndrome and the transmission rate of balanced inversion 8 in the Hispanic population of the southwestern United States.

A rec(8) dup(q) syndrome, secondary to a pericentric inversion--inv(8)(p23q22)--has been identified in 26 probands from Hispanic kindreds in the southwestern United States. The clinical phenotype of the Hispanic rec(8) syndrome includes a dysmorphic facies, cardiovascular and urinary-tract malformations, and mental retardation. Segregation analysis utilizing pedigree and cytogenetic data from 31 kindreds including five additional kindreds from additional sources has provided computation of genetic risks for counseling.

CNS monoamine levels and the effect of DSP4 on ethanol sensitivity in LS and SS mice.

Brain area monoamine levels were determined in selectively-bred ethanol sensitive (LS) and insensitive (SS) mice. Norepinephrine, dopamine and serotonin were measured using high performance liquid chromatography coupled with electrochemical detection. Brain regions studied included cerebellum, brain stem, striatum, frontal cortex, hippocampus and hypothalamus.

Genetic correlation of ethanol-induced ataxia and cerebellar Purkinje neuron depression among inbred strains and selected lines of rats.

In the present study, we compared phenotypic differences in behavioral and neurophysiological responses to acute ethanol administration among six inbred rat strains. Genetic variation was found both for ataxia, as measured by loss of righting response (sleep time) after a hypnotic dose of ethanol, and for the depressant action of ethanol on the spontaneous discharge of cerebellar Purkinje neurons. Results from an analysis of covariance of these phenotypes, measured among the inbred strains, provided strong evidence for a high genetic correlation between sleep time and inhibition of cerebellar Purkinje neuron discharge in response to acute ethanol administration.

Genetic brain polypeptide variants in inbred mice and in mouse strains with high and low sensitivity to alcohol.

Twelve genetically determined brain polypeptide charge variants were identified by comparing cerebellar vermis of 7 inbred mouse strains and of mice selectively bred from 8 strains closely related to these 7 ancestral strains and one other for acute behavioral sensitivity to the sedative effects of ethanol. The selectively bred ethanol-sensitive (LS, long sleep) and insensitive (SS, short sleep) mice exhibited different allelic variants at 6 of these 12 gene loci expressed in the cerebellum. Variant polypeptide A1 (81 kdalton, pI 5.

Application of a high performance liquid chromatography method for screening of aldehyde dehydrogenase isozyme deficiency in hair roots from different ethnic groups.

A sensitive high performance liquid chromatography method has been used to measure aldehyde dehydrogenase (ALDH) activity in hair roots from Caucasian and Japanese subjects. Kinetic studies confirmed previous isoelectric focusing results that hair roots from Caucasians have two forms of ALDH, one low Km form and another high Km form, while hair roots from Japanese individuals who show a flushing reaction after ethanol intake lack, or have low activity of, the low Km form. By taking the ratio of the activities measured at a low (3 microM) and a high (75 microM) concentration of the substrate (3,4-dihydroxyphenylacetaldehyde), a suitable index for ALDH deficiency was obtained.

Correlative analysis of ethanol-related phenotypes in rat inbred strains.

As a summary presentation of the ethanol-related traits in the rat inbred strains, the responses to ethanol for various traits of the eight strains were analyzed. The intercorrelations among the means of the strains were computed and the interrelationships among the strain correlations were determined further by partial correlation and factor analysis. Sources of data on strain ethanol response included measures from laboratories of Drs.

Effects of phencyclidine, amphetamine and related compounds on dopamine release from and uptake into striatal synaptosomes.

The ability of phencyclidine (PCP), amphetamine and other substances to stimulate dopamine release from and inhibit dopamine uptake into rat striatal synaptosomes was examined in a continuous superfusion system. Inhibition of uptake was measured by determining inhibition of [3H]dopamine displacement by unlabeled dopamine ([1H]dopamine). The displacement of [3H]dopamine by 10(-7) M [1H]dopamine was temperature- and sodium-sensitive and calcium-independent.

Risk of Down syndrome among second- and third-degree relatives of a proband with trisomy 21.

Previous studies indicate that parents who have had one child with trisomy 21 have an increased risk of having another affected child. To establish whether sibs, aunts, uncles, and cousins of an index case with trisomy 21 are also at increased risk for having an affected child, 219 kindreds of trisomy 21 probands were surveyed and compared with a control group of 247 kindreds. Control kindreds were ascertained through a child with a nonchromosomal disorder.