Roger Bourne

Magnetic resonance spectroscopy detects biochemical changes in the brain associated with chronic low back pain: a preliminary report

Magnetic resonance (MR) spectroscopy is a noninvasive technique that can be used to detect and measure the concentration of metabolites and neurotransmitters in the brain and other organs. We used in vivo 1H MR spectroscopy in subjects with low back pain compared with control subjects to detect alterations in biochemistry in three brain regions associated with pain processing. A pattern recognition approach was used to determine whether it was possible to discriminate accurately subjects with low back pain from control subjects based on MR spectroscopy. MR spectra were obtained from the prefrontal cortex, anterior cingulate cortex, and thalamus of 32 subjects with low back pain and 33 control subjects without pain. Spectra were analyzed and compared between groups using a pattern recognition method (Statistical Classification Strategy). Using this approach, it was possible to discriminate between subjects with low back pain and control subjects with accuracies of 100%, 99%, and 97% using spectra obtained from the anterior cingulate cortex, thalamus, and prefrontal cortex, respectively. These results demonstrate that MR spectroscopy, in combination with an appropriate pattern recognition approach, is able to detect brain biochemical changes associated with chronic pain with a high degree of accuracy.

Digital tomosynthesis: A new future for breast imaging?

The aim of this article is to review the major limitations in current mammography and to describe how these may be addressed by digital breast tomosynthesis (DBT). DBT is a novel imaging technology in which an x-ray fan beam sweeps in an arc across the breast, producing tomographic images and enabling the production of volumetric, three-dimensional (3D) data. It can reduce tissue overlap encountered in conventional two-dimensional (2D) mammography, and thus has the potential to improve detection of breast cancer, reduce the suspicious presentations of normal tissues, and facilitate accurate differentiation of lesion types. This paper reviews the latest studies of this new technology. Issues including diagnostic efficacy, reading time, radiation dose, and level of compression; cost and new innovations are considered.

16 T Diffusion microimaging of fixed prostate tissue: Preliminary findings

Diffusion tensor microimaging was used to investigate the water diffusion properties of formalin‐fixed prostate tissue at spatial resolution approaching the cellular scale. Diffusion tensor microimaging was performed at 16.4 T with 40 μm isotropic voxels. Diffusion tensor microimaging clearly demonstrated distinct microscopic diffusion environments and tissue architecture consistent with that seen on light microscopy of the same tissue. The most restricted diffusion environment is the secretory epithelial cell layer (voxel bulk mean diffusivity, D = 0.4 ± 0.1 × 10−3 mm2/sec). Diffusion in the fibromuscular stromal matrix is relatively less restricted (D = 0.7 ± 0.1 × 10−3 mm2/sec). In tumor tissue (Gleason pattern 4+4) distinct glandular and ductal structures are absent in the diffusion‐weighted images and diffusivity is low (D = 0.5 ± 0.1 × 10−3 mm2/sec). Distinct stromal and epithelial diffusion compartments are the most likely origin of biexponential diffusion decay observed in vivo. Magn Reson Med, 2011.

Fundamentals of digital imaging in medicine

Digital Images.- Medical Images.- The Spatial and Frequency Domains.- Image Quality.- Contrast Adjustment.- Image Filters.- Spatial Transformation.- ImageJ.- A Note on Precision and Accuracy.- Complex Numbers.This article reviews Fundamentals of Digital Imaging in Medicine by Roger Bourne , London, Limited 2010, €79.95 (

Determination of Grade and Receptor Status from the Primary Breast Lesion by Magnetic Resonance Spectroscopy

99.00). ISBN 978-1-84882-086-9, 200 pp. (paperback).

Information Theoretic Ranking of Four Models of Diffusion Attenuation in Fresh and Fixed Prostate Tissue Ex Vivo

Magnetic resonance spectra (MRS) from fine needle aspiration biopsies (FNAB) from primary breast lesions were analysed using a pattern recognition method, Statistical Classification Strategy, to assess tumor grade and oestrogen receptor (ER) and progesterone receptor (PgR) status. Grade 1 and 2 breast cancers were separated from grade 3 cancers with a sensitivity and specificity of 96% and 95%, respectively. The ER status was predicted with a sensitivity of 91% and a specificity of 90%, and the PgR status with a sensitivity of 91% and a specificity of 86%. These classifiers provide rapid and reliable, computerized information and may offer an objective method for determining these prognostic indicators simultaneously with the diagnosis of primary pathology and lymph node involvement.

Microscopic diffusion anisotropy in formalin fixed prostate tissue: preliminary findings.

To compare the theoretical information content of four popular models of diffusion‐weighted signal attenuation.

Biexponential diffusion decay in formalin‐fixed prostate tissue: Preliminary findings

Diffusion tensor microimaging at 16.4 T with 40 μm isotropic voxels was used to investigate anisotropic water diffusion in prostate tissue at spatial resolution approaching the cellular scale. Nine normal glandular tissue samples were collected from the peripheral zone of six formalin fixed radical prostatectomy specimens. Fibromuscular stromal tissue exhibited microscopic diffusion anisotropy (mean fractional anisotropy range 0.47–0.66) significantly higher (P < 0.01, Students t‐test) than in epithelium‐containing voxels (mean fractional anisotropy range 0.31–0.54) in six of the seven normal tissue samples in which both compartments could be measured. Fiber tracking demonstrated principle stromal fiber directions consistent with myocyte orientation seen on light microscopy of the same sample. Diffusion tensor microimaging may be valuable for investigation of variable results from attempts to measure diffusion anisotropy in the prostate in vivo. Magn Reson Med, 2012.

Assessment of non-Gaussian diffusion with singly and doubly stretched biexponential models of diffusion-weighted MRI (DWI) signal attenuation in prostate tissue.

Magnetic resonance microimaging was used to measure diffusion decay over an extended b‐factor range in a formalin‐fixed normal prostate sample and a Gleason pattern 3+4 cancer tissue sample. The coefficients of biexponential fits to diffusion decay data from 1600 voxels of dimension 160 × 160 × 160 μm3 in each sample were correlated with underlying epithelial and stromal compartment partial volumes estimated from high‐resolution apparent diffusion coefficient (ADC) data (40 × 40 × 40 μm3 voxels) from the same tissue. In the normal tissue sample, the signal fractions of the low and high ADC components of the biexponential fits correlated linearly with partial volumes of epithelial tissue (R2 = 0.6) and stromal tissue (R2 = 0.5), respectively. Similar but weaker correlations were observed in the cancer sample. Epithelium‐containing high spatial resolution voxels appeared to be composed of ∼60% low ADC and ∼40% high ADC component. Stromal voxels appeared to be composed of ∼20% low ADC and ∼80% high ADC component. This preliminary report suggests that distinctly different diffusion properties in microscopically adjacent cell types contribute to the multiexponential diffusion decay phenomenon in prostate tissue. Magn Reson Med, 2012.

Effect of formalin fixation on biexponential modeling of diffusion decay in prostate tissue.

Non‐Gaussian diffusion dynamics was investigated in the two distinct water populations identified by a biexponential model of diffusion in prostate tissue. Diffusion‐weighted MRI (DWI) signal attenuation was measured ex vivo in two formalin‐fixed prostates at 9.4 T with diffusion times Δ = 10, 20 and 40 ms, and b values in the range 0.017–8.2 ms/µm2. A conventional biexponential model was compared with models in which either the lower diffusivity component or both of the components of the biexponential were stretched. Models were compared using Akaikes Information Criterion (AIC) and a leave‐one‐out (LOO) test of model prediction accuracy. The doubly stretched (SS) model had the highest LOO prediction accuracy and lowest AIC (highest information content) in the majority of voxels at Δ = 10 and 20 ms. The lower diffusivity stretching factor (α2) of the SS model was consistently lower (range ~0.3–0.9) than the higher diffusivity stretching factor (α1, range ~0.7–1.1), indicating a high degree of diffusion heterogeneity in the lower diffusivity environment, and nearly Gaussian diffusion in the higher diffusivity environment. Stretched biexponential models demonstrate that, in prostate tissue, the two distinct water populations identified by the simple biexponential model individually exhibit non‐Gaussian diffusion dynamics. Copyright