Flattening filter removal for improved image quality of megavoltage fluoroscopy.

Purpose: Removal of the linear accelerator (linac) flattening filter enables a high rate of dose deposition with reduced treatment time. When used for megavoltage imaging, an unflat beam has reduced primary beam scatter resulting in sharper images. In fluoroscopic imaging mode, the unflat beam has higher photon count per image frame yielding higher contrast-to-noise ratio.

Gated treatment delivery verification with on-line megavoltage fluoroscopy.

Purpose: To develop and clinically demonstrate the use of on-line real-time megavoltage (MV) fluoroscopy for gated treatment delivery verification.

Methods And Materials: Megavoltage fluoroscopy (MVF) image sequences were acquired using a flat panel equipped for MV cone-beam CT in synchrony with the respiratory signal obtained from the Anzai gating device. The MVF images can be obtained immediately before or during gated treatment delivery.

Compromised myelin integrity during psychosis with repair during remission in drug-responding schizophrenia.

Functional connection among the information-processing (grey-matter) centres within the CNS are necessary for the coordinated processing of perception, affect, thought and behaviour. Myelinated neuronal bundles provide the links among such processing centres. Magnetic resonance diffusion tensor imaging (DTI) can assess the physical integrity of myelin.

Computer automated detection of head orientation for prevention of wrong-side treatment errors.

A medical error can occur when a patient is positioned in a medical imaging device such as an MRI scanner if information regarding their orientation is improperly entered into the device control software. If such an error is not detected and corrected, the erroneous orientation data will be stored in the image header information and will propagate with the images throughout the medical enterprise. Presented here is a fully automated algorithm for computing patient head orientation from the image data and detecting errors in image orientation labeling.

Risk for early-onset schizophrenia assessed via gray-matter distributions.

Automated image analysis algorithms were used to measure regional gray matter volumes in children with early-onset schizophrenia. Logistic regression analysis of gray matter volumes within Brodman areas was used to test the ability to predict whether a subject was normal or schizophrenic. The ROC area-under-the-curve was 0.

Magnetic resonance imaging study of brain asymmetries in dyslexic patients.

Research studies suggest that the left hemisphere is involved in the pathophysiology of dyslexia. Thus far, the exact location and nature of the purported lesion(s) remain a matter of contention. The present study describes the distribution of structural abnormalities as related to brain symmetry in the brains of dyslexic individuals.

Volume increases in striatum associated with positive symptom reduction in schizophrenia: a preliminary observation.

Eleven drug-free patients with a DSM-IV diagnosis of schizophrenia who were in a period of psychotic exacerbation were treated with antipsychotics for 4 weeks. To evaluate treatment-associated changes in the basal ganglia and in psychotic symptomatology, the patients were studied with magnetic resonance imaging and with the Scale for the Assessment of Positive Symptoms. Serial assessments of striatal volumes and psychotic symptoms were performed at baseline and at 4 weeks of treatment; dual assessments of striatal volumes were also performed in 11 untreated normal controls.

Cerebral cortical gray expansion associated with two second-generation antipsychotics.

Background: Second-generation antipsychotics (SGAs) differ from first-generation antipsychotics (FGAs) with respect to induction of less extrapyramidal morbidity, partially reducing negative symptoms, and causing modest improvement in neurocognitive functioning in patients with schizophrenia. SGAs demonstrate 5-HT2a antagonism. Differential effects of SGAs and FGAs on cortical gray volumes are explored herein.

State-related thalamic changes during antipsychotic treatment in schizophrenia: preliminary observations.

Thalamic volumes and psychotic symptoms were assessed during psychotic exacerbation and during antipsychotic drug treatment. Reduction of psychotic symptoms (SAPS) during four weeks of treatment was highly correlated with volumetric expansion as measured by magnetic resonance imaging in both left and right thalamus [r(s)=0.75 and r(s)=0.

Normalization of brain magnetic resonance images using histogram even-order derivative analysis.

The even-ordered (2nd, 4th and 6th) derivatives of a brain MRI histogram were used to calculate a characteristic value for white matter, which was used to normalize the image intensity scale. Simulated image histograms were used to estimate the methodological error as a function of noise level, and the optimum derivative order was determined for each image type studied (T1-, T2- and density-weighted). The algorithm yielded highly reproducible results when used in conjunction with a threshold-sensitive brain segmentation algorithm.

Software-annotated, digitally photographed, and printed MR images: suitability for publication.

Rationale And Objectives: The authors performed this study to evaluate whether digitally photographed, computer-annotated MR images produced by clinical radiologists and printed with an inexpensive photo printer are suitable for publication.

Materials And Methods: Laser prints of 20 magnetic resonance images of the brain were photographed with a 3-megapixel digital camera and annotated with arrows, arrowheads, and asterisks by using graphics software that incorporates vector support. Then, 5 x 7-inch glossy prints with white borders were made by using an inexpensive photo printer.