Spurious leptomeningeal enhancement on immediate post-operative MRI for paediatric brain tumours.

Immediate post-operative MRI has been recommended as an accurate and robust method to assess residual brain tumour. Early enhancement at the resection margin and in the dura is well recognized, but we describe two cases of enhancement in the basal cisterns on immediate post-operative MRI that resolved on follow-up. The underlying cause of the enhancement remains to be elucidated, but it should be recognized that leptomeningeal enhancement may occur after surgery and that this does not necessarily imply tumour spread.

Entropy minimization and spectral dissimilarity curve resolution technique applied to nuclear magnetic resonance data sets.

The use of entropy minimization and spectral dissimilarity is applied to three nuclear magnetic resonance (NMR) data sets. The data sets contain 2, 2, and 3 observables each. It was found that without any a priori information the sets of pure component spectra underlying the NMR spectroscopic observations could be extracted.

Diffusion tensor imaging for the assessment of upper motor neuron integrity in ALS.

Background: High angular resolution diffusion tensor imaging (HARD) is an MRI technique that exploits the mobility of water molecules to yield maps of structural order and directionality of white matter tracts with greater precision than six-direction diffusion tensor imaging (DTI) schemes.

Objective: To assess whether HARD is more sensitive than conventional MRI or neurologic assessment in detecting the upper motor neuron (UMN) pathology of patients with ALS.

Methods: Twenty-five patients with definite UMN clinical signs and 23 healthy volunteers underwent conventional MRI.

Intracranial MR venography in children: normal anatomy and variations.

Background And Purpose: Little information is available regarding the anatomy of the intracranial veins and sinuses that can be shown on MR venograms of children. The aim of this study was to determine the normal venous anatomy and anatomic variants.

Methods: Fifty children who were referred for investigation of developmental delay and who had normal results of MR imaging of the brain were recruited into the study.

Ultrasound measured renal length versus low dose CT volume in predicting single kidney glomerular filtration rate.

Ultrasound measured renal length and CT measured renal volume are potential surrogate markers for single kidney glomerular filtration rate (SKGFR). The aims of this study are to determine: (1) the repeatability of ultrasound measured length and low radiation dose spiral CT measured volume; (2) the relationship between renal length and volume; and (3) whether length and/or volume is a predictor of SKGFR. 69 patients with suspected renal artery stenosis underwent ultrasound renal length measurement, CT evaluation of renal volume and assessment of SKGFR.

Band-target entropy minimization (BTEM) applied to hyperspectral Raman image data.

Band-target entropy minimization (BTEM) has been applied to extraction of component spectra from hyperspectral Raman images. In this method singular value decomposition is used to calculate the eigenvectors of the spectroscopic image data set. Bands in non-noise eigenvectors that would normally be used for recovery of spectra are examined for localized spectral features.

Band-target entropy minimization. A robust algorithm for pure component spectral recovery. Application to complex randomized mixtures of six components.

A newly developed self-modeling curve resolution method, band-target entropy minimization (BTEM), is described. This method starts with the data decomposition of a set of spectroscopic mixture data using singular value decomposition. It is followed by the transformation of the orthonormal basis vectors/loading vectors into individual pure component spectra one at a time.

Proton MR spectroscopy of polymicrogyria and heterotopia.

Background And Purpose: Proton MR spectroscopy of the brain allows noninvasive in vivo assessment of metabolites, which may be useful in understanding the biology of malformations of cortical development. The aim of this study was to determine the MR spectroscopic characteristics of polymicrogyria and heterotopia compared with those of normal frontal lobe white matter.

Methods: We recruited 22 patients with radiographic findings characteristic of polymicrogyria, nine patients with radiographic findings characteristic of heterotopia, and 10 control subjects into the study.

The Rh4(CO)12-catalyzed hydroformylation of 3,3-dimethylbut-1-ene promoted with HMn(CO)5. Bimetallic catalytic binuclear elimination as an origin for synergism in homogeneous catalysis.

The bimetallic origins of catalytic synergism were studied using unmodified rhodium and manganese carbonyls as catalyst precursors during the low-temperature hydroformylation of 3,3-dimethylbut-1-ene to 4,4-dimethylpentanal in n-hexane solvent (T approximately 298 K, P(CO) = 1.0-4.0 MPa, P(H2) = 0.

Can pre-operative computed tomography predict resectability of ovarian carcinoma at primary laparotomy?

Objective: To assess the ability of computed tomography in predicting whether suspected ovarian cancer could be fully excised at primary laparotomy.

Design: Retrospective analysis of patient notes and pre-operative computed tomography scans. Setting A UK NHS cancer centre.

Pure component spectral reconstruction from mixture data using SVD, global entropy minimization, and simulated annealing. Numerical investigations of admissible objective functions using a synthetic 7-species data set.

A combination of singular value decomposition, entropy minimization, and simulated annealing was applied to a synthetic 7-species spectroscopic data set with added white noise. The pure spectra were highly overlapping. Global minima for selected objective functions were obtained for the transformation of the first seven right singular vectors.

3D gadolinium-enhanced MRI venography: evaluation of central chest veins and impact on patient management.

Aim: To assess the value of a simplified 3D gadolinium-enhanced magnetic resonance imaging (MRI) venography for central chest veins.

Materials And Methods: In this retrospective study of 24 patients, the MRI findings and medical records were reviewed to determine whether MRI results correlated with subsequent findings, and to determine the effect on clinical management. 3D steady state gradient-echo sequence, fast imaging with steady state precession (FISP), was used.