Publications by authors named "Ioannis Stavrou"

18 Publications

  • Page 1 of 1

An extensive case study on the dispersion parameters of HI-assisted reduced graphene oxide and its graphene oxide precursor.

J Colloid Interface Sci 2020 Nov 11;580:332-344. Epub 2020 Jul 11.

Department of Electrical & Computer Engineering, Hellenic Mediterranean University, Heraklion 71410, Crete, Greece. Electronic address:

The formation of highly concentrated and stable graphene derivatives dispersions remains a challenge towards their exploitation in various applications, including flexible optoelectronics, photovoltaics, 3D-printing, and biomedicine. Here, we demonstrate our extensive investigation on the dispersibility of graphene oxide (GO) and reduced graphene oxide (RGO) in 25 different solvents, without the use of any surfactant or stabilizer. Although there is a significant amount of work covering the general field, this is the first report on the dispersibility of: a) RGO prepared by a HI/AcOH assisted reduction process, the method which yields RGO of higher graphitization degree than the other well-known reductants met in the literature, b) both GO and RGO, explored in such a great range of solvents, with some of them not previously reported. In addition, through calculation of their Hansen Solubility Parameters (HSP), we confirmed their dispersibility behavior in each solvent, while we indirectly validated the most advanced graphitization degree of the studied RGO compared to other reported RGOs, since its HSPs exhibit the highest similarity with the respective ones of pure graphene. Finally, high concentrations of up to 189 μg mL for GO and ~ 87.5 μg mL for RGO were achieved, in deionized water and o-Dichlorobenzene respectively, followed by flakes size distribution and polydispersity indices estimation, through dynamic light scattering as a quality control of the effect of a solvent's nature on the dispersion behavior of these graphene-based materials.
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http://dx.doi.org/10.1016/j.jcis.2020.07.040DOI Listing
November 2020

Synergistic enantioseparation systems with either cyclodextrins or cyclofructans and L-alanine Tert butyl ester lactate.

Electrophoresis 2019 02 27;40(4):539-546. Epub 2018 Nov 27.

Department of Chemistry, University of Cyprus, Nicosia, Cyprus.

The combined use of chiral ionic liquids (CILs) and conventional chiral selectors (CSs) in CE, to establish a synergistic system, has proven to be an effective approach for the separation of enantiomeric pairs. In this study, a new CE method was developed, employing a binary system of a CS, either a cyclodextrin (CD) or a cyclofructan (CF), and a chiral amino acid ester-based ionic liquid (AAIL), for the chiral separation of four basic, acidic and zwitterionic drug compounds. In particular, the enantioseparation of two anticoagulants, warfarin (WAR) and coumachlor (COU), a non-opioid analgesic, nefopam (NEF) and a third-generation antihistamine, fexofenadine (FXD), was examined, by supporting the BGE with a CS and the chiral AAIL L-alanine tert butyl ester lactate (L-AlaC Lac). Parameters, such as the type of the CS, the concentration of both the CS and L-AlaC Lac, and the BGE pH, were methodically examined in order to optimize the chiral separation of each analyte. It was observed that, in some cases, the addition of the AAIL into the BGE improved both resolution (R ) and efficiency (N) significantly. In other cases, the synergistic effect enabled baseline separation of analyte enantiomers, at a much lower concentration of the CS. Finally, after optimization of separation conditions, baseline separations (R >1.5) of all four analytes were achieved in less than 5 min.
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http://dx.doi.org/10.1002/elps.201800257DOI Listing
February 2019

Polyphenols in carobs: A review on their composition, antioxidant capacity and cytotoxic effects, and health impact.

Food Chem 2018 Dec 2;269:355-374. Epub 2018 Jul 2.

Department of Chemistry, University of Cyprus, 1678 Nicosia, Cyprus. Electronic address:

Carob (Ceratonia Siliqua L., tree of the pea family Fabaceae) and its products have recently attracted great interest due to their polyphenolic composition. This review summarizes the polyphenolic compounds that are contained in different carob parts (leaves, pod, seeds, barks) and products (syrup, flour, fiber). It also states the main differences of polyphenolic composition due to environmental and natural reasons, such as region, variety, and gender, and due to the processes used for preparation, extraction and analysis. The gender, along with the extraction procedure, proved to be the most important factors affecting the polyphenolic composition. Supercritical fluid extraction is the most efficient technique used because it protects polyphenols from decomposition. Due to the relatively low number of publications, it is concluded that further development of optimum methods for extraction, analysis and isolation of polyphenols should be carried over to assess their antioxidant capacity and their food technological and pharmaceutical industry.
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http://dx.doi.org/10.1016/j.foodchem.2018.06.152DOI Listing
December 2018

Chiral selectors in CE: Recent development and applications (mid-2014 to mid-2016).

Electrophoresis 2017 03 1;38(6):786-819. Epub 2017 Feb 1.

Department of Chemistry, University of Cyprus, Nicosia, Cyprus.

This report, which is a sequence of a series of reviews, records the most important chiral selectors (CSs) applied in CE. It highlights the CSs that were used during the period 2014 to mid-2016. In this review, method developments, validations, and pharmaceutical along with biomedical applications are presented. The different CSs include CDs, antibiotics, cyclofructants, linear and branched oligo- and polysaccharides, and polymeric surfactants. In addition, the advantages of these CSs, along with their chiral recognition mechanisms, and their performance, are discussed.
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http://dx.doi.org/10.1002/elps.201600322DOI Listing
March 2017

Enantioseparations in open-tubular capillary electrochromatography: Recent advances and applications.

J Chromatogr A 2016 Oct 19;1467:145-154. Epub 2016 Jul 19.

Department of Chemistry, University of Cyprus, 1678 Nicosia, Cyprus.

This review highlights recent advances and applications in open-tubular capillary electrochromatography (OT-CEC) for enantioseparations during the last decade. Although extensive research has been conducted in the area of separations by use of CEC, and a big number of reviews have been published, there is not a review on exclusively the use of chiral stationary phases (CSPs) in OT-CEC for enantioseparations. Therefore, in this review, the design and synthesis of different CSPs are presented, and their potential applications in OT-CEC for enantioseparations are discussed. The different approaches to CSP development include chiral nanomaterials, porous layers, molecular imprinting, sol-gel technique, polyelectrolyte multilayer coating, polymeric coating and others.
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http://dx.doi.org/10.1016/j.chroma.2016.07.039DOI Listing
October 2016

Stress-related phenomena and detoxification mechanisms induced by common pharmaceuticals in alfalfa (Medicago sativa L.) plants.

Sci Total Environ 2016 07 31;557-558:652-64. Epub 2016 Mar 31.

Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, 3603 Lemesos, Cyprus. Electronic address:

Pharmaceutically active compounds (PhACs) have been recently shown to exert phytotoxic effects. The present study explores the uptake, systemic translocation, and abiotic stress responses and detoxification mechanisms induced by the exposure of alfalfa plants grown in sand under greenhouse conditions to four common, individually applied PhACs (10μgL(-1)) (diclofenac, sulfamethoxazole, trimethoprim, 17a-ethinylestradiol) and their mixture. Stress physiology markers (lipid peroxidation, proline, H2O2 and NO content, antioxidant activity assays) and gene expression levels of key plant detoxification components (including glutathione S-transferases, GST7, GST17; superoxide dismutases, CuZnSOD, FeSOD; proton pump, H(+)-ATP, and cytochrome c oxidase, CytcOx), were evaluated. PhACs were detected in significantly higher concentrations in roots compared with leaves. Stress related effects, manifested via membrane lipid peroxidation and oxidative burst, were local (roots) rather than systemic (leaves), and exacerbated when the tested PhACs were applied in mixture. Systemic accumulation of H2O2 in leaves suggests its involvement in signal transduction and detoxification responses. Increased antioxidant enzymatic activities, as well as upregulated transcript levels of GST7, GST17, H(+)-ATPase and CytcOx, propose their role in the detoxification of the selected PhACs in plants. The current findings provide novel biochemical and molecular evidence highlighting the studied PhACs as an emerging abiotic stress factor, and point the need for further research on wastewater flows under natural agricultural environments.
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http://dx.doi.org/10.1016/j.scitotenv.2016.03.054DOI Listing
July 2016

Combined use of cyclofructans and an amino acid ester-based ionic liquid for the enantioseparation of huperzine A and coumarin derivatives in CE.

Electrophoresis 2015 Dec 7;36(24):3061-8. Epub 2015 Oct 7.

Department of Chemistry, University of Cyprus, Nicosia, Cyprus.

Cyclofructans (CFs) and their derivatives have recently been proven to be efficient chiral selectors (CSs) for the enantioseparation of several analytes in CE, HPLC, and GC. In this study, the chiral separation ability of a number of native and derivatized CFs was examined in CE. Particularly, six different CFs, with different derivatization groups and cavity sizes [native CF-6 and CF-7, isopropyl cyclofructan-6 (IPCF-6), IPCF-7, sulfated cyclofructan-6 (SCF-6), and SCF-7] were used as CSs for the enantioseparation of huperzine A, warfarin, and coumachlor. Almost all of the examined CFs, except from SCF-6 & -7, demonstrated relatively low and sometimes no chiral separation ability for huperzine A. In an effort to improve both resolution and efficiency, the chiral ionic liquid D-Alanine tert butyl ester lactate (D-AlaC4Lac) was added into the BGE. In most of the cases, the combination of CF with D-AlaC4Lac resulted in an improvement in peak efficiency and/or resolution. When CF-6 was utilized with D-AlaC4Lac, a resolution of 1.4 was obtained, while the use of IPCF-6/D-AlaC4Lac provided a baseline enantioseparation. Although the combination of SCF-7 and 40 mM D-AlaC4Lac did not affect resolution, it dramatically increased peak efficiency from 24,000 to 117,000. In the case of warfarin and coumachlor, IPCF-6 and IPCF-7 proved to be the most effective CSs. It is, therefore, concluded that the size of the cavity and the CF derivatization are the key parameters for the chiral separation capability. It is also clear from this study that D-AlaC4Lac is necessary for improved peak efficiencies and resolutions.
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http://dx.doi.org/10.1002/elps.201500367DOI Listing
December 2015

Chiral selectors in CE: recent developments and applications (2012-mid 2014).

Electrophoresis 2015 Jan 17;36(1):101-23. Epub 2014 Nov 17.

Department of Chemistry, University of Cyprus, Nicosia, Cyprus.

There is a large number of chiral selectors (CSs) that have, over the years, been synthesized and used in electrophoretic enantioseparations. This report highlights the most important CSs applied in CE during the period 2012 to mid-2014. It is mainly focused on method developments and validations, along with pharmaceutical and biomedical applications. Even though numerous publications have, through the years, reported the utilization of CSs in enantioseparations, only the ones applied in electrophoretic techniques the last approximately three years are demonstrated in this review article. In particular, cyclodextrins, cyclofructants, linear and branched oligo- and polysaccharides, antibiotics, and polymeric surfactants are presented, and their advantages, their chiral recognition mechanisms, and their performance are discussed.
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http://dx.doi.org/10.1002/elps.201400310DOI Listing
January 2015

Chiral ionic liquids in chromatographic and electrophoretic separations.

J Chromatogr A 2014 Oct 28;1363:2-10. Epub 2014 May 28.

Department of Chemistry, University of Cyprus, 1678 Nicosia, Cyprus.

This report provides an overview of the application of chiral ionic liquids (CILs) in separation technology, and particularly in capillary electrophoresis and both gas and liquid chromatography. There is a large number of CILs that have been synthesized and designed as chiral agents. However, only a few have successfully been applied in separation technology. Even though this application of CILs is still in its early stages, the scientific interest is increasing dramatically. This article is focused on the use of CILs as chiral selectors, background electrolyte additives, chiral ligands and chiral stationary phases in electrophoretic and chromatographic techniques. Different examples of CILs, which contain either a chiral cation, a chiral anion or both, are presented in this review article, and their major advantages along with their potential applications in chiral electrophoretic and chromatographic recognition are discussed.
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http://dx.doi.org/10.1016/j.chroma.2014.05.059DOI Listing
October 2014

Microsurgery and radiosurgery for brainstem cavernomas: effective and complementary treatment options.

World Neurosurg 2014 Mar-Apr;81(3-4):520-8. Epub 2014 Jan 16.

Department of Neurosurgery, Medical University Vienna, Vienna, Austria.

Objective: To evaluate treatment options for brainstem cavernous malformations (BSCMs) using the results from a center with long-standing experience in microsurgical resection and Gamma Knife radiosurgery (GKRS) treatment of BSCMs.

Methods: Study participants were 67 symptomatic patients with BSCMs who were treated either microsurgically (n = 29) or radiosurgically (n = 38). Patients were followed for a minimum of 2 years (median, 7.7 years). A recent follow-up was performed.

Results: Patients receiving surgical treatment had mainly large, superficially seated lesions and experienced preoperative hemorrhages more often and presented with higher preoperative modified Rankin Scale scores. Patients receiving GKRS harbored smaller, deep-seated lesions, reflecting a selection bias. In both treatment groups, patients presented with significantly better modified Rankin Scale scores at follow-up than before intervention. Overall annual preoperative hemorrhage rates were 3.2% in microsurgery patients and 2.3% in radiosurgery patients. In the preoperative observation period, the rehemorrhage rate was 25.1% for microsurgery patients and 7.2% for radiosurgery patients. Hemorrhage rate after GKRS decreased significantly to 0.6% after 2 years. The postoperative hemorrhage rate was 8.8% but only for microsurgery patients with residual lesions. Advancements in microsurgical techniques improved surgical outcomes, resulting in a high total excision rate in the modern era.

Conclusions: In the treatment of BSCM, patient selection and timing of surgery are crucial. If applied in a multidisciplinary neurosurgical center, microsurgery and radiosurgery are complementary treatment options that both result in reduced bleeding rates and improvement of clinical outcome.
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http://dx.doi.org/10.1016/j.wneu.2014.01.004DOI Listing
June 2014

Chiral separation of the clinically important compounds fucose and pipecolic acid using CE: determination of the most effective chiral selector.

Chirality 2013 Sep 11;25(9):556-60. Epub 2013 Jun 11.

Department of Chemistry, University of Cyprus, Nicosia, Cyprus.

In this study, simple electrophoretic methods were developed for the chiral separation of the clinically important compounds fucose and pipecolic acid. In recent years, these analytes, and particularly their individual enantiomers, have attracted considerable attention due to their role in biological functions and disorders. The detectability and sensitivity of pipecolic acid and fucose were improved by reacting them with fluorenylmethyloxycarbonyl chloride (FMOC-Cl) and 5-amino-2-naphthalene-sulfonic acid (ANSA), respectively. The enantioseparation conditions were optimized by initially investigating the type of the chiral selector. Different chiral selectors, such as polymeric surfactants and cyclodextrins, were used and the most effective ones were determined with regard to resolution and analysis time. A 10-mM β-cyclodextrin was able to separate the enantiomers of ANSA-DL-fucose and the polymeric surfactant poly(sodium N-undecanoyl-LL-leucine-valinate) was able to separate the enantiomers of FMOC-DL-pipecolic acid, with resolution values of 3.45 and 2.78, respectively. Additional parameters, such as the concentration and the pH of the background electrolyte (BGE), the concentration of the chiral selector, and the addition of modifiers were examined in order to optimize the separations. The addition of the chiral ionic liquid D-alanine tert-butyl ester lactate into the BGE was also investigated, for the first time, in order to improve resolution of the enantiomers.
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http://dx.doi.org/10.1002/chir.22170DOI Listing
September 2013

Facile preparation of polysaccharide-coated capillaries using a room temperature ionic liquid for chiral separations.

Electrophoresis 2013 May;34(9-10):1334-8

Department of Chemistry, University of Cyprus, Nicosia, Cyprus.

In this study, the dissolution of polysaccharides into an ionic liquid was investigated and applied as a coating onto the capillary walls of a fused-silica capillary in open-tubular CEC. The coating was evaluated by examining the chiral separation of two analytes (thiopental, sotalol) with three cellulose derivatives (cellulose acetate, cellulose acetate phthalate, and cellulose acetate butyrate). Baseline separation of thiopental enantiomers was achieved by use of each polysaccharide coating (Rs: 7.0, 8.1, 7.1), while sotalol provided partial resolution (Rs: 0.7, 1.0, 0.9). In addition, reproducibility of the cellulose-coated capillaries was evaluated by estimating the run-to-run and capillary-to-capillary RSD values of the EOF. Both stability and reproducibility were very good with RSD values of less than 7%.
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http://dx.doi.org/10.1002/elps.201200563DOI Listing
May 2013

Use of chiral amino acid ester-based ionic liquids as chiral selectors in CE.

Electrophoresis 2013 Feb;34(4):524-30

Department of Chemistry, University of Cyprus, Nicosia, Cyprus.

In this study, the applicability of a chiral ionic liquid (CIL) as the sole chiral selector in CE was investigated for the first time. In particular, five amino acid ester-based CILs were synthesized and used as additives in the BGE in order to evaluate their chiral recognition ability. The performance of these CILs as the sole chiral selectors was evaluated by using 1,1'-binaphthyl-2,2-diylhydrogenphosphate (BNP) as the analyte and by comparing the resolution values. Different parameters were examined, such as the alkyl group bulkiness and the configuration of the cation, the anion type of the CIL and its concentration, and the pH of the BGE, in order to optimize the separation of the enantiomers and to demonstrate the effect that each parameter has on the chiral-recognition ability of the CIL. Baseline separation of BNP within 13 min was achieved by using a BGE of 100 mM Tris/10 mM sodium tetraboratedecahydrate (pH 8) and a chiral selector of 60 mM l-alanine tert butyl ester lactate. The run-to-run and batch-to-batch reproducibilities were also evaluated by computing the %RSD values of the EOF and the two enantiomer peaks. In both cases, very good reproducibilities were observed, since all %RSD values were below 1%.
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http://dx.doi.org/10.1002/elps.201200469DOI Listing
February 2013

Long-term seizure control after resection of supratentorial cavernomas: a retrospective single-center study in 53 patients.

Neurosurgery 2008 Nov;63(5):888-96; discussion 897

Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.

Objective: The goal of this study was to examine the long-term outcomes of 53 epilepsy patients who were surgically treated for supratentorial cavernomas in a single-center study and to assess both the duration of epilepsy and the resection of the hemosiderin rim for their prognostic relevance during extended follow-up.

Methods: Fifty-three patients underwent microsurgical resection of radiologically diagnosed supratentorial cavernomas. For the outcome analysis, they were divided into 2 groups: Group A (33 patients) with a preoperative duration of epilepsy of less than 2 years, and Group B (20 patients) with a preoperative duration of epilepsy of 2 years or more. The natural history of the cavernomas, localization and size of the lesions, use of antiepileptic drugs, surgery timing, and technique (removal or not of the surrounding gliosis) were evaluated retrospectively. The outcome of epilepsy was based on Engel's classification and the International League Against Epilepsy classification.

Results: After a mean follow-up period of 8.1 years, 45 (84.9%) of the 53 patients were free from disabling seizures (Engel Class I), including 37 patients (69.8%) who were completely free of postoperative seizures (Engel Class IA); 43 patients (81.1%) were categorized as International League Against Epilepsy Class 1. Outcome was statistically significantly improved in the patient subgroup of our study in which patients underwent a resection of the surrounding gliosis after a preoperative duration of epilepsy of less than 2 years (Group A). There was no mortality, and only minor postoperative neurological deficits occurred in 7.5% of patients.

Conclusion: In a long-term follow-up period, 84.9% of the patients in the study could be evaluated as Engel Class I. The analysis of outcome showed that patients benefited significantly from early surgery and excision of the hemosiderin rim.
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http://dx.doi.org/10.1227/01.NEU.0000327881.72964.6EDOI Listing
November 2008

Improved preoperative evaluation of cerebral cavernomas by high-field, high-resolution susceptibility-weighted magnetic resonance imaging at 3 Tesla: comparison with standard (1.5 T) magnetic resonance imaging and correlation with histopathological findings--preliminary results.

Invest Radiol 2007 Jun;42(6):346-51

MR Centre of Excellence, Department of Radiology, Medical University Vienna, Vienna, Austria.

Objectives: To compare high-field, high-resolution, susceptibility-weighted magnetic resonance imaging (3 Tesla [T] HR-SW-MRI) and standard (1.5 Tesla [T]) MRI for the detection of cerebral cavernomas. To evaluate the ability of 3 T HR-SW-MRI to visualize intralesional structures compared with standard (1.5 T) MRI, in correlation with histopathologic findings.

Materials And Methods: Seventeen patients with cerebral cavernomas underwent both standard (1.5 T) MRI (T1-SE, T2-TSE, T2*-GRE) and 3 T HR-SW-MRI (TR/TE 43.3/9.1 millisecond; 512 x 384 x 48 matrix; FOV 250 mm; SI 72 mm) at our institution. All MR images were evaluated by 3 radiologists in consensus for detectability, size (1 cm), and conspicuity (good, acceptable, poor) of the lesions at both field strengths, and for the presence of hypointense intralesional tubular structures. In 7 patients, MR findings were correlated with histopathologic findings.

Results: Both 3 T HR-SW-MRI and standard (1.5 T) MRI detected 22 lesions in 17 patients; 3 T HR-SW-MRI detected an additional 7 lesions in 6 patients. On average, 3 T HR-SW-MRI detected 1.706 +/- 0.92 (median = 1) lesions per patient, whereas standard (1.5 T) MRI detected 1.235 +/- 0.664 lesions per patient (P = 0.016). Lesion conspicuity was good in all 3 T HR-SW-MR images and good in 68.2% and acceptable in 31.8% of standard (1.5 T) MR images (P = 0.016). In 22 lesions detected at both field strengths, 3 T HR-SW-MRI demonstrated intralesional tubular structures in 72.7% and standard (1.5 T) MRI demonstrated these structures in 31.8% (P = 0.001). Intralesional tubular structure correlated to conglomerates of cavernous vessel, as verified by histopathology.

Conclusion: Compared with standard (1.5 T) MRI, 3 T HR-SW-MRI allows superior detection and characterization of cerebral cavernomas. Despite increased susceptibility effects, ie, signal loss at higher magnetic field strengths, the visualization of intralesional tubular structures is feasible. This may be helpful in the diagnosis, presurgical planning, and noninvasive follow-up after gamma-knife radiosurgery.
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http://dx.doi.org/10.1097/01.rli.0000262744.85397.fcDOI Listing
June 2007

Globular radiopacity around the apex of an impacted maxillary third molar.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007 May 27;103(5):594-8. Epub 2007 Feb 27.

University of Athens, Athens, Greece.

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http://dx.doi.org/10.1016/j.tripleo.2006.11.050DOI Listing
May 2007

Are cerebral cavernomas truly nonenhancing lesions and thereby distinguishable from arteriovenous malformations? MRI findings and histopathological correlation.

Magn Reson Imaging 2006 Jun 13;24(5):631-7. Epub 2006 Feb 13.

Department of Radiology/MR Centre of Excellence, Medical University Vienna/General Hospital Vienna, 1090 Vienna, Austria.

Purpose: The aim of this study was to determine whether cerebral cavernomas are truly nonenhancing lesions on magnetic resonance imaging (MRI), whether they can be distinguished from arteriovenous malformations (AVM) on that basis and to evaluate the incidence of their association with developmental venous anomalies (DVA).

Patients And Methods: Thirty-two patients who underwent neurosurgical operation for a cerebral vascular malformation and had a standard MRI conclusive of cerebral cavernoma were retrospectively evaluated for size of the lesions, contrast enhancement of the lesion and the coexistence of DVA. The contrast uptake of these lesions was investigated, and contrast enhancement was classified as none, moderate or marked. The incidence of an associated DVA was also investigated. The radiological findings were subsequently correlated with neurohistopathological findings.

Results: No difference was found between the contrast enhancement of cavernomas and AVMs. Cross tables were calculated for contrast enhancement and size, which demonstrated no statistically significant correlation. Cross tables were calculated for contrast enhancement and histopathological diagnosis, which revealed that both entities presented variable degrees of contrast enhancement and were thereby not distinguishable from each other on the basis of contrast enhancement. We found an association of cavernoma with DVA in 30% of cases.

Conclusion: Neither a correlation between the absence of contrast enhancement and the histopathological diagnosis of cavernoma nor the size and contrast enhancement was found. We conclude that cavernomas present with variable degrees of contrast enhancement on MRI and, thus, are definitely not distinguishable from AVM on the basis of contrast enhanced MRI. We found an association between cavernomas and DVA in approximately one third of patients.
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http://dx.doi.org/10.1016/j.mri.2005.10.037DOI Listing
June 2006

Diffusion-weighted imaging in the assessment of brain abscesses therapy.

AJNR Am J Neuroradiol 2004 Sep;25(8):1310-7

Department of Radiology, Neuroradiology Section, University Hospital, Vienna, Austria.

Background And Purpose: Surgically or conservatively treated brain abscesses may resolve, or pus may re-accumulate, requiring further intervention or treatment change. We hypothesized that diffusion-weighted (DW) imaging is useful in depicting features of abscesses related to therapeutic success or failure.

Methods: Conventional contrast-enhanced T1- and T2-weighted imaging and DW imaging were performed in seven patients (aged 30-69 years) with proved pyogenic brain abscesses. The center of the abscess was qualitatively and quantitatively analyzed at initial and follow-up imaging in all patients. We correlated the signal intensity on trace DW images and the apparent diffusion coefficients (ADCs) with the clinical and laboratory data, particularly with respect to treatment failure and repeat therapy.

Results: Surgical drainage was performed in six patients; one patient was treated with only antibiotics. All abscess cavities initially had high signal intensity (restricted diffusion) on DW images, with a mean ADC value of 0.52 x 10 (-3)mm (2)/s. Low signal intensity at DW imaging with high ADC were seen on follow-up images in the patient receiving medication and in four patients in whom the abscesses were drained; this correlated with a good therapeutic response. Two patients underwent drainage; their second follow-up DW images showed areas of high signal intensity and low ADC values suggesting re-accumulation of pus. Increased C-reactive protein level and WBC count correlated well with DW image findings.

Conclusion: DW imaging was superior to conventional MR imaging in evaluating the success or failure of abscess therapy. Restricted diffusion in a drained abscess corresponded to pus.
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September 2004