Marianna Jakab

An MRI study of temporal lobe abnormalities and negative symptoms in chronic schizophrenia

Previous magnetic resonance imaging (MRI) studies have reported various subtle brain abnormalities in schizophrenic patients, including temporal lobe abnormalities, which are of particular interest given the role of this brain region in auditory and language processing, and the characteristic deficits in these processes in schizophrenia. Subjects in this study were 16 male patients diagnosed with chronic schizophrenia and 15 healthy male comparison subjects. These patients were characterized by negative symptoms. High spatial resolution coronal MRI 1.5-mm-thick slices were used to measure the gray matter volume of the superior temporal gyrus, anterior and posterior amygdala/hippocampal complex, and parahippocampal gyrus. Patients, relative to normal comparison subjects, evinced a reduction of gray matter volume in bilateral superior temporal gyri and anterior amygdala/hippocampal complex. The reduction in gray matter of the superior temporal gyrus in patients with schizophrenia is consistent with previous findings, and is noteworthy in that it was found in this group of patients with predominantly negative symptoms. The reduction in the anterior amygdala/hippocampal complex was an additional temporal lobe finding. These results underscore the role of temporal lobe structures in the pathophysiology of schizophrenia.

Quantitative Follow-up of Patients With Multiple Sclerosis Using MRI: Reproducibility

The reproducibility of an automated method for estimating the volume of white matter abnormalities on brain magnetic resonance (MR) images of multiple sclerosis (MS) patients was evaluated. Twenty MS patients underwent MR imaging twice within 30 minutes. Measurement variability is introduced mainly by MRI acquisition and image registration procedures, which demonstrate significantly worse reproducibility than the image segmentation. The correction of partial volume artifacts is essential for sensitive measurements of overall lesion burden. The average lesion volume difference (bias) between two MR exams of the same MS patient (N = 20) was 0.05 cm3, with a 95% confidence interval between −0.17 and +0.28 cm3, suggesting that the proposed measurement system is suitable for clinical follow‐up trials, even in relatively small patient cohorts. The limits of agreement for lesion volume were between −1.3 and +1.5 cm3, implying that in individual patients changes in lesion load need to be at least this large to be detected reliably. This automated method for estimating lesion burden is a reliable tool for the evaluation of MS progression and exacerbation in patient cohorts and potentially also in individual patients. J. Magn. Reson. Imaging 1999; 9:509–518.

Towards improved ultrasound-based analysis and 3D visualization of the fetal brain using the 3D Slicer

Magnetic resonance imaging (MRI) provides useful three-dimensional (3D) information; however, there are some restrictions on its use during pregnancy due to safety concerns. In addition, fetal movements can create artifacts on MR images, as image quality depends on position of the fetus and placenta. In the past decade, 3D ultrasound imaging has been used in clinical practice to investigate the formation and volumetric size of critical anatomical structures of the fetus. However, current techniques rely mainly on analysis of sections of interest that do not integrate anatomical information concerning the shape of these structures. We provide a brief description of a workflow for semi-automated segmentation and 3D visualization of fetal ultrasound volumes in the second trimester using the 3D Slicer open source software1,2. Our workflow allowed quantitative image analysis of the choroid plexus and cerebrum from 3D ultrasound images. We acquired 3D ultrasound volumes from five healthy pregnant women at 12 (n=2), 14 (n=2) and 19 (n=1) weeks of gestation. Informed consent was obtained in each case. We used a Voluson E6 (GE Medical Systems, Zipf, Austria) ultrasound machine with a RAB4-8-D/OB D/4D 8-MHz transabdominal transducer. Our workflow consisted of four steps (Figure 1). Firstly, we imported DICOM (digital imaging and communications in medicine) ultrasound volumes into the 3D Slicer. We then used the ‘Grow Cut Segmentation’ algorithm3 of the interactive Editor module to extract critical structures from the ultrasound volumes. We reconstructed 3D surface models from segmented regions using the ‘Marching Cubes’ algorithm4, and finally computed the volume of 3D anatomical models using the ‘Label Statistics’ module of the software. Figure 1 Flowchart describing the 3D Slicer workflow used in this study. DICOM, digital imaging and communications in medicine. Figure 2 shows a 3D surface model of the choroid plexus and cerebrum reconstructed from the original 3D ultrasound volumes. The corresponding volumes of these structures at 12, 14 and 19 weeks’ gestation were, respectively: 431.1mm3, 698.9mm3 and 1203.3 mm3 for the choroid plexus and 183.6 mm3, 282.8 mm3 and 469.8 mm3 for the cerebrum. Figure 2 Result of ‘Grow Cut Segmentation’ of the fetal brain using the 3D Slicer. The blue structure represents the choroid plexus, and the yellow structure the cerebrum at 14 weeks of gestation (axial and coronal views). Using the 3D Slicer, we were able to obtain patient-specific quantitative information and 3D visualization of anatomical structures within the fetal brain. We anticipate being able to perform segmentation that accurately matches the anatomy using different methods. We believe this method, combined with ultrasound or MRI data, will be helpful in monitoring fetal development and detecting anomalies of the brain as well as other anatomical structures.

The National Alliance for Medical Image Computing, a roadmap initiative to build a free and open source software infrastructure for translational research in medical image analysis

The National Alliance for Medical Image Computing (NA-MIC), is a multi-institutional, interdisciplinary community of researchers, who share the recognition that modern health care demands improved technologies to ease suffering and prolong productive life. Organized under the National Centers for Biomedical Computing 7 years ago, the mission of NA-MIC is to implement a robust and flexible open-source infrastructure for developing and applying advanced imaging technologies across a range of important biomedical research disciplines. A measure of its success, NA-MIC is now applying this technology to diseases that have immense impact on the duration and quality of life: cancer, heart disease, trauma, and degenerative genetic diseases. The targets of this technology range from group comparisons to subject-specific analysis.

Holographic video display of time-series volumetric medical data

We describe an animated electro-holographic visualization of brain lesions due to the progression of multiple sclerosis. A research case study is used which documents the expression of visible brain lesions in a series of magnetic resonance imaging (MRI) volumes collected over the interval of one year. Some of the salient information resident within this data is described, and the motivation for using a dynamic spatial display to explore its spatial and temporal characteristics is stated. We provide a brief overview of spatial displays in medical imaging applications, and then describe our experimental visualization pipeline, from the processing of MRI datasets, through model construction, computer graphic rendering, and hologram encoding. The utility, strengths and shortcomings of the electro-holographic visualization are described and future improvements are suggested.