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1.
Diagn Interv Imaging ; 98(10): 699-706, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28645678

ABSTRACT

PURPOSE: The goal of this retrospective study was to investigate the differential diagnosis of endolymphatic hydrops in patients with Meniere's disease (MD) symptoms by using magnetic resonance imaging (MRI) with intravenous injection of gadolinium chelate and delayed acquisition. MATERIAL AND METHOD: Two hundred patients (133 women, 67 men; mean age=67.2±11 ([SD] years) with unilateral MD underwent MRI at 3-T, between 4.5 and 5.5hours after intravenous administration of gadoterate meglumine at a dose of 0.1mmol/kg. MR images were analyzed for the presence of saccular hydrops, perilymphatic fistulae, inner ear malformations, semicircular canal (SCC) abnormal enhancement and brain lesions. We also tested the potential relationship between past history of gentamicin intratympanic administration and perilymphatic fistula presence and SCC aspect. RESULTS: Saccular hydrops were found in 96/200 patients with MD (48%). Three patients (1.5%) had perilymphatic fistulas associated with saccular hydrops, as confirmed by surgery. There was a correlation between the presence of perilymphatic fistula and past history of intratympanic gentamicin administration (P=0.02). We detected inner ear malformations in 5 patients (2.5%), SCC local enhancement in 15 patients (7.5%) always on the same side than the clinical symptoms of MD. There was a correlation between the presence of SCC abnormal enhancement and past intratympanic gentamicin administration (P=0.001). Five patients (2.5%) had brain lesions along central cochleovestibular pathways. CONCLUSION: MRI may reveal brain lesions, SCC abnormalities and perilymphatic fistulae in patients with clinical MD.


Subject(s)
Endolymphatic Hydrops/diagnostic imaging , Magnetic Resonance Imaging , Meniere Disease/complications , Aged , Brain Diseases/diagnostic imaging , Case-Control Studies , Cochlear Diseases/diagnostic imaging , Contrast Media , Diagnosis, Differential , Ear, Inner/abnormalities , Ear, Inner/diagnostic imaging , Female , Fistula/diagnostic imaging , Humans , Male , Retrospective Studies , Semicircular Canals/abnormalities , Semicircular Canals/diagnostic imaging
2.
Oral Dis ; 23(5): 572-575, 2017 Jul.
Article in English | MEDLINE | ID: mdl-27422846

ABSTRACT

Surgical resection is currently the best treatment for salivary gland tumors. A reliable magnetic resonance imaging mapping, encompassing tumor grade, location, and extension may assist safe and effective tumor resection and provide better information for patients regarding potential risks and morbidity after surgical intervention. However, direct examination of the tumor grade and extension using conventional morphological MRI remains difficult, often requiring contrast media injection and complex algorithms on perfusion imaging to estimate the degree of malignancy. In addition, contrast-enhanced MRI technique may be problematic due to the recently demonstrated gadolinium accumulation in the dentate nucleus of the cerebellum. Significant developments in magnetic resonance diffusion imaging, involving voxel-based quantitative analysis through the measurement of the apparent diffusion coefficient, have enhanced our knowledge on the different histopathological salivary tumor grades. Other diffusion imaging-derived techniques, including high-order tractography models, have recently demonstrated their usefulness in assessing the facial nerve location in parotid tumor context. All of these imaging techniques do not require contrast media injection. Our review starts by outlining the physical basis of diffusion imaging, before discussing findings from diagnostic studies testing its usefulness in assessing salivary glands tumors with diffusion MRI.


Subject(s)
Diffusion Magnetic Resonance Imaging , Diffusion Tensor Imaging , Salivary Gland Neoplasms/diagnostic imaging , Contrast Media , Humans , Preoperative Period
3.
Eur Radiol ; 25(10): 3043-9, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25820480

ABSTRACT

OBJECTIVES: Recurrent peripheral vestibulopathy (RPV) is a public health problem, yet the aetiology remains unclear. Recent developments in MRI of endolymphatic hydrops (EH) allow for a better understanding of inner ear disorders. We intended to study the prevalence of EH in patients with RPV, in comparison to those with Meniere's disease (MD). METHODS: MRI examinations were performed 4 hours after intravenous injection of gadoteric acid in 132 patients with RPV (n = 64) and MD (n = 68). Two radiologists retrospectively studied the prevalence and localization of EH in RPV and MD groups. Patients were graded based on the number and localization of hydrops, between 1 (EH in either cochlea or vestibule on one side) and 4 (EH in cochlea and vestibule on both ears). RESULTS: We identified EH in 31 out of 64 patients and in 61 out of 68 patients in the RPV and MD groups, respectively. There was a significant difference regarding the number of subjects with EH between the two groups (p ≤ 0.01), with a higher average number of hydrops localization in MD group (p ≤ 0.01). CONCLUSION: MRI may reveal EH in some cases among patients with RPV, suggesting a similar pathophysiological mechanism in comparison with MD. KEY POINTS: • MRI may reveal endolymphatic hydrops in some patients with recurrent peripheral vestibulopathy. • We suggest a similar pathophysiological mechanism in recurrent vestibulopathy and Meniere's Disease. • MRI with delayed acquisition helps clinicians to assess patients with recurrent vestibulopathy. • The outcome would be to aid the development of adapted therapeutic strategies. • MRI of endolymphatic hydrops should probably be included in future diagnostic protocols.


Subject(s)
Endolymphatic Hydrops/diagnosis , Vestibular Diseases/diagnosis , Cochlea , Contrast Media , Diagnosis, Differential , Female , Humans , Injections, Intravenous , Magnetic Resonance Imaging/methods , Male , Meniere Disease/diagnosis , Middle Aged , Observer Variation , Physical Examination , Recurrence , Retrospective Studies
4.
Diagn Interv Imaging ; 94(12): 1259-78, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24011870

ABSTRACT

The functional imaging of perfusion enables the study of its properties such as the vasoreactivity to circulating gases, the autoregulation and the neurovascular coupling. Downstream from arterial stenosis, this imaging can estimate the vascular reserve and the risk of ischemia in order to adapt the therapeutic strategy. This method reveals the hemodynamic disorders in patients suffering from Alzheimer's disease or with arteriovenous malformations revealed by epilepsy. Functional MRI of the vasoreactivity also helps to better interpret the functional MRI activation in practice and in clinical research.


Subject(s)
Brain/blood supply , Cerebrovascular Circulation , Magnetic Resonance Imaging , Cerebrovascular Disorders/diagnosis , Humans
5.
J Neuroradiol ; 40(2): 94-100, 2013 May.
Article in English | MEDLINE | ID: mdl-22727617

ABSTRACT

High-field 3 T magnetic resonance imaging (MRI) has entered standard clinical practice over the past decade, and its advantages have already been suggested in areas such as neural, musculoskeletal, pelvic and angiographic imaging. However, high-field systems still pose challenges in terms of their specific absorption rate (SAR) and radiofrequency (RF) excitation uniformity. Thus, the aim of the present study was to evaluate the impact, on both these factors, of standard quadrature against parallel RF transmission technology (dual-source parallel RF excitation [DSPE]) in spinal examination at 3 T. The thoracolumbar spine was examined with three different sequences: T1-weighted (T1w); T2-weighted (T2w); and T2w short tau inversion recovery (STIR). Each was acquired with and without DSPE. The manufacturer's implementation of this technology has been associated with optimized handling of patient SAR exposure, resulting in a 38.4% reduction in acquisition time. On comparing sequences with equal repetition times (TRs), the acquisition time reduction was 44.4%. Thus, DSPE allows a reduction in acquisition time. This gain is accompanied by augmentation of the whole-body SAR and diminution of the local SAR. Image quality improvement due to more homogeneous effective transmit B1 was mainly observed at the junction of the thoracolumbar spine.


Subject(s)
Artifacts , Image Enhancement/methods , Lumbar Vertebrae/anatomy & histology , Magnetic Resonance Imaging/methods , Spinal Cord/anatomy & histology , Thoracic Vertebrae/anatomy & histology , Whole Body Imaging/methods , Adult , Algorithms , Female , Humans , Image Interpretation, Computer-Assisted/methods , Male , Middle Aged , Radiation Dosage , Reproducibility of Results , Sensitivity and Specificity
6.
Magn Reson Med ; 69(6): 1677-82, 2013 Jun.
Article in English | MEDLINE | ID: mdl-22829470

ABSTRACT

Quantification of cerebral blood flow using QUIPSSII pulsed arterial spin labeling requires that the QUIPSS saturation delay TI1 is shorter than the natural temporal bolus width. Yet the duration of the bolus of tagged spins entering the region of interest varies during vasoactive stimuli such as gaseous challenges or across subjects due to differences in blood velocity or vessel geometry. A new technique, bolus turbo sampling, to rapidly measure the duration of the inflowing bolus is presented. It allows to optimize the arterial spin labeling acquisition to ensure reliable quantification of perfusion while maximizing the arterial spin labeling signal by avoiding the use of unnecessarily short label durations. The average bolus width measured in the right and left middle cerebral artery territories using the bolus turbo sampling technique has a repeatability coefficient of 75 ms and correlates significantly with the TI1,max determined from a novel multi-TI1 protocol (R=0.65, P<0.05). The possibility to measure the bolus width under hypercapnia is demonstrated.


Subject(s)
Cerebrovascular Circulation/physiology , Contrast Media/pharmacokinetics , Magnetic Resonance Angiography/methods , Middle Cerebral Artery/physiology , Models, Cardiovascular , Adult , Blood Flow Velocity/physiology , Computer Simulation , Female , Humans , Male , Middle Cerebral Artery/anatomy & histology , Pulsatile Flow/physiology , Sample Size , Spin Labels , Young Adult
7.
Neuroimage ; 58(2): 579-87, 2011 Sep 15.
Article in English | MEDLINE | ID: mdl-21745581

ABSTRACT

OBJECTIVE: To evaluate the cerebral vasoreactivity using blood oxygenation level dependent functional MRI during carbogen inhalation with 7% CO(2) in Alzheimer's disease and amnestic mild cognitive impairment. PARTICIPANTS AND METHODS: Thirty nine subjects were included to be investigated using blood oxygenation level dependent (BOLD) functional MRI at 1.5T during a block-design carbogen inhalation paradigm, with a high concentration face-mask under physiological monitoring. Basal cerebral perfusion was measured using pulsed arterial spin labeling. Image analyses were conducted using Matlab® and SPM5 with physiological regressors and corrected for partial volume effect. RESULTS: Among selected participants, 12 subjects were excluded because of incomplete protocol, leaving for analysis 27 subjects without significant microangiopathy diagnosed for Alzheimer's disease (n=9), amnestic mild cognitive impairment (n=7), and matched controls (n=11). No adverse reaction related to the CO(2) challenge was reported. Carbogen inhalation induced a whole-brain signal increase, predominant in the gray matter. In patients, signal changes corrected for gray matter partial volume were decreased (0.36±0.13% BOLD/mmHg in Alzheimer's disease, 0.36±0.12 in patients with mild cognitive impairment, 0.62±0.20 in controls). Cerebral vasoreactivity impairments were diffuse but seemed predominant in posterior areas. The basal hypoperfusion in Alzheimer's disease was not significantly different from patients with mild cognitive impairment and controls. Among clinical and biological parameters, no effect of apoE4 genotype was detected. Cerebral vasoreactivity values were correlated with cognitive performances and hippocampal volumes. Among age and hippocampal atrophy, mean CVR was the best predictor of the mini-mental status examination. CONCLUSION: This BOLD functional MRI study on CO(2) challenge shows impaired cerebral vasoreactivity in patients with Alzheimer's disease and amnestic mild cognitive impairment at the individual level. These preliminary findings using a new MRI approach may help to better characterize patients with cognitive disorders in clinical practice and further investigate vaso-protective therapeutics.


Subject(s)
Alzheimer Disease/pathology , Alzheimer Disease/physiopathology , Carbon Dioxide/pharmacology , Cerebrovascular Circulation/drug effects , Oxygen/blood , Aged , Atrophy , Cognitive Dysfunction , Data Interpretation, Statistical , Female , Hemodynamics/drug effects , Hemodynamics/physiology , Hippocampus/pathology , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Neuropsychological Tests , Regression Analysis , Spin Labels
9.
Phys Med Biol ; 52(16): 4881-92, 2007 Aug 21.
Article in English | MEDLINE | ID: mdl-17671341

ABSTRACT

Synchrotron stereotactic radiotherapy (SSR) is a radiotherapy technique that makes use of the interactions of monochromatic low energy x-rays with high atomic number (Z) elements. An important dose-enhancement can be obtained if the target volume has been loaded with a sufficient amount of a high-Z element, such as iodine. In this study, we compare experimental dose measurements, obtained with normoxic polymer gel (nPAG), with Monte Carlo computations. Gels were irradiated within an anthropomorphic head phantom and were read out by magnetic resonance imaging. The dose-enhancement due to the presence of iodine in the gel (iodine concentration: 5 and 10 mg ml(-1)) was measured at two radiation energies (35 and 80 keV) and was compared to the calculated factors. nPAG dosimetry was shown to be efficient for measuring the sharp dose gradients produced by SSR. The agreement between 3D gel dosimetry and calculated dose distributions was found to be within 4% of the dose difference criterion and a distance to agreement of 2.1 mm for 80% of the voxels. Polymer gel doped with iodine exhibited higher sensitivity, in good agreement with the calculated iodine-dose enhancement. We demonstrate in this preliminary study that iodine-doped nPAG could be used for measuring in situ dose distributions for iodine-enhanced SSR treatment.


Subject(s)
Gels/radiation effects , Iodine/radiation effects , Polymers/radiation effects , Radiometry/methods , Radiosurgery/methods , Dose-Response Relationship, Radiation , Iodine/chemistry , Radiotherapy Dosage , Reproducibility of Results , Sensitivity and Specificity , Synchrotrons
10.
J Radiol ; 88(3 Pt 2): 444-71, 2007 Mar.
Article in French | MEDLINE | ID: mdl-17457257
11.
Rev Neurol (Paris) ; 162(12): 1204-20, 2006 Dec.
Article in French | MEDLINE | ID: mdl-17151513

ABSTRACT

INTRODUCTION: In a few years, magnetic resonance imaging (MRI) has evolved from a morphology-based examination to one that encompasses metabolism and function. STATE OF ART: MRI is a well-established tool for the initial evaluation of brain tumors, but conventional MR sequences have some limitations. Conventional MRI is unable to distinguish high-grade glioma from metastasis and abscess, to define precisely the histopathological grade of gliomas, to determine exactly the limits of tumor extension, to characterize meningeal tumors. Differentiation of tumor recurrence from treatment-related changes may be difficult with standard MR imaging because the interpretation is essentially based on volume analysis. PERSPECTIVES: 1H Spectroscopy, diffusion and perfusion imaging become possible with the development of MR imagers and can be routinely performed in clinical settings. They give complementary information about tumor metabolism and vascularity and allow a better analysis of post-treatment modifications. Functional and metabolic explorations should be used to characterize brain tumors.


Subject(s)
Magnetic Resonance Imaging/methods , Supratentorial Neoplasms/diagnosis , Adult , Astrocytoma/diagnosis , Astrocytoma/pathology , Glioblastoma/diagnosis , Glioblastoma/pathology , Glioma/diagnosis , Glioma/pathology , Humans , Oligodendroglioma/diagnosis , Oligodendroglioma/pathology , Supratentorial Neoplasms/pathology
12.
J Radiol ; 87(6 Pt 2): 807-21, 2006 Jun.
Article in French | MEDLINE | ID: mdl-16778749

ABSTRACT

Perfusion MR Imaging is useful for initial diagnosis and follow up of brain tumors. Dynamic susceptibility contrast MR imaging is described. The limitations and advantages of this technique are discussed with respect to quantification and interpretation of results.


Subject(s)
Brain Neoplasms/diagnosis , Magnetic Resonance Angiography , Humans , Male , Middle Aged
13.
J Radiol ; 87(6 Pt 1): 607-17, 2006 Jun.
Article in French | MEDLINE | ID: mdl-16788535

ABSTRACT

In the last decade, functional MRI (fMRI) has become one of the most widely used functional imaging technique in neurosciences. However, its clinical applications remain limited. Despite methodological and practical issues, fMRI data has been validated by different techniques (magnetoencephalography, Wada test, electrical and magnetic stimulations, and surgical resections). In neurosurgical practice, fMRI can identify eloquent areas involved in motor and language functions, and may evaluate characteristics of postoperative neurological deficit including its occurrence, clinical presentation and duration. This may help to inform patients and to prepare postoperative care. fMRI may also identify epileptic foci. In neurological practice, fMRI may help to determine prognosis of recovery after stroke, appropriate medication, and rehabilitation. fMRI may help to identify patients at risk of developing Alzheimer disease. Finally, cerebrovascular reactivity imaging is an interesting approach that might provide new radiological insights of vascular function.


Subject(s)
Brain Diseases/diagnosis , Magnetic Resonance Imaging , Brain/metabolism , Brain Diseases/metabolism , Humans , Magnetic Resonance Imaging/methods , Oxygen/blood
14.
Neurochirurgie ; 51(3-4 Pt 2): 287-98, 2005 Sep.
Article in French | MEDLINE | ID: mdl-16292173

ABSTRACT

OBJECT: To discuss the pertinency of perfusion MR imaging for initial diagnosis and follow up of brain tumors. METHODOLOGY: Dynamic susceptibility contrast MR imaging was applied. Images were thus obtained with intensities proportional to the cerebral blood volume (CBV). Relative cerebral blood volume (rCBV) maps were then generated by normalizing the signal intensities with respect to measurements made in healthy tissue. RESULTS: The method provided interesting data for establishing the differential diagnosis between different kinds of lesions, in particular between lymphoma and pilocytic astrocytoma, and for grading gliomas. DISCUSSION AND CONCLUSION: Limits of the approach are discussed, in particular with respect to quantification aspects and interpretation of the results. The approach could be particularly useful for grading oligodendrogliomas, for which histological diagnosis on biopsy is sometimes difficult.


Subject(s)
Brain Neoplasms/diagnosis , Oligodendroglioma/diagnosis , Astrocytoma/blood supply , Astrocytoma/diagnosis , Astrocytoma/surgery , Biopsy , Brain/diagnostic imaging , Brain/pathology , Brain/surgery , Brain Neoplasms/blood supply , Brain Neoplasms/surgery , Cerebrovascular Circulation , Diagnosis, Differential , Female , Follow-Up Studies , Glioma/blood supply , Glioma/diagnosis , Glioma/surgery , Humans , Lymphoma/diagnosis , Lymphoma/surgery , Magnetic Resonance Imaging , Male , Meningeal Neoplasms/blood supply , Meningeal Neoplasms/diagnosis , Meningeal Neoplasms/surgery , Meningioma/blood supply , Meningioma/diagnosis , Meningioma/surgery , Middle Aged , Neoplasm Staging , Oligodendroglioma/surgery , Tomography, Emission-Computed, Single-Photon
16.
MAGMA ; 17(3-6): 313-6, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15580376

ABSTRACT

Vessel size index (VSI) measurements have been validated on rats bearing a glioma with high doses of contrast agent. The aim of this study was to evaluate the impact of using a reduced dose of contrast agent, necessary for clinical trials. Experiments were performed on rats at three doses of AMI-227 and clearly show higher VSI values at lower doses, whatever the region of interest (contralateral, peritumoral and intratumoral tissue). These results are in good correlation with Monte-Carlo simulations on healthy brain and suggest that only relative values can be obtained at clinical contrast agent doses and magnetic fields.


Subject(s)
Brain Neoplasms/blood supply , Brain Neoplasms/pathology , Iron/administration & dosage , Magnetic Resonance Imaging/methods , Microcirculation/pathology , Neovascularization, Pathologic/pathology , Oxides/administration & dosage , Animals , Cell Line, Tumor , Contrast Media/administration & dosage , Corpus Striatum/blood supply , Corpus Striatum/pathology , Dextrans , Dose-Response Relationship, Drug , Ferrosoferric Oxide , Glioma/blood supply , Glioma/pathology , Image Enhancement/methods , Magnetite Nanoparticles , Male , Rats , Rats, Wistar , Reproducibility of Results , Sensitivity and Specificity
17.
Br J Cancer ; 91(2): 374-80, 2004 Jul 19.
Article in English | MEDLINE | ID: mdl-15188003

ABSTRACT

While morphological and molecular events during angiogenesis in brain glioma have been extensively studied, the functional properties of tumour vessels have yet received little attention. We have determined changes in regional blood volume (BV) during graded hypoxic hypoxia using susceptibility contrast magnetic resonance imaging in a model of rat brain glioma. Nine anaesthetised and ventilated rats with C6 glioma were subjected to incremental reduction in the fraction of inspired oxygen (FiO(2)): 0.35, 0.25, 0.15, 0.12, 0.10 and reoxygenation to 0.35. At each episode, BV was determined in peritumoral, intratumoral and contralateral regions. Baseline BV values (FiO(2) of 0.35) were higher in peritumoral than in the contralateral and intratumoral regions. Progressive hypoxia resulted in a graded increase in BV in contralateral and peritumoral regions. At FiO(2) of 0.10, BV increases were comparable between these two regions: 49+/-22% (s.d.) and 28+/-17% with respect of control values, respectively. These BV changes reversed during the reoxygenation episode. By contrast, the intratumoral region had a significant increase in BV at FiO(2) of 0.10 only, with no evidence of return to the basal value during reoxygenation. Immunohistochemical staining of alpha-smooth muscle actin confirmed reactivity of vessels in the peritumoral region. Our findings indicate that peritumoral vessels present a vascular reactivity to hypoxia, which is comparable to that of nontumoral vessels. A method is thus available for noninvasively demonstrating whether any particular vascular modifying strategy results in the desired outcome in terms of tumour blood volume changes.


Subject(s)
Blood Volume/physiology , Brain Neoplasms/blood supply , Cerebrovascular Circulation/physiology , Glioma/blood supply , Hypoxia, Brain/physiopathology , Animals , Brain Neoplasms/pathology , Female , Glioma/pathology , Magnetic Resonance Imaging , Oxygen/physiology , Rats , Rats, Wistar
18.
J Neuroradiol ; 31(2): 145-7, 2004 Mar.
Article in French | MEDLINE | ID: mdl-15094653

ABSTRACT

Although rare in non immunodeficient patients, the correct diagnosis of brain abscess is essential in order to initiate urgent medical and surgical treatment. We describe the imaging features including spectroscopy and diffusion MRI.


Subject(s)
Brain Abscess/diagnosis , Cerebral Cortex/pathology , Cerebral Cortex/diagnostic imaging , Diffusion Magnetic Resonance Imaging , Humans , Magnetic Resonance Imaging , Magnetic Resonance Spectroscopy , Male , Middle Aged , Radiography
19.
Magn Reson Med ; 51(3): 533-41, 2004 Mar.
Article in English | MEDLINE | ID: mdl-15004795

ABSTRACT

Vessel size imaging (VSI) for brain tumor characterization was evaluated and the vessel size index measured by MRI (VSIMRI) was correlated with VSI obtained by histology (VSIhisto). Blood volume (BV) and VSI maps were obtained on 12 rats by simultaneous measurements of R2* and R2, before and after the injection of a macromolecular contrast agent, AMI-227. Immunostaining of collagen IV in vessels was performed. An expression was derived for evaluating VSI from stereologic measurements on histology data (VSIhisto). On BV and VSI images obtained from large-size tumors (n = 9), three regions could be distinguished and correlated well with histological sections: a high BV region surrounding the tumor, a necrotic area where BV is very low, and a viable tumor tissue region showing lower BV but higher VSI than the normal rat cortex, with the presence of larger vessels. The quantitative analysis showed a good correlation (Spearman rank's rho = 0.74) between VSIhisto and VSIMRI with a linear regression coefficient of 1.17. The good correlation coefficient supports VSI imaging as a quantitative method for tumor vasculature characterization.


Subject(s)
Brain Neoplasms/blood supply , Glioma/blood supply , Magnetic Resonance Imaging , Neovascularization, Pathologic/pathology , Animals , Blood Volume/physiology , Brain Neoplasms/pathology , Collagen Type IV/analysis , Contrast Media , Dextrans , Disease Models, Animal , Ferrosoferric Oxide , Glioma/pathology , Image Enhancement , Image Processing, Computer-Assisted , Immunohistochemistry , Iron , Linear Models , Macromolecular Substances , Magnetite Nanoparticles , Male , Microcirculation/pathology , Necrosis , Oxides , Rats , Rats, Wistar , Statistics, Nonparametric
20.
Radiat Res ; 158(6): 763-70, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12452779

ABSTRACT

In this paper we describe the results of experiments using synchrotron radiation to trigger the Auger effect in living human cancer cells treated with a widely used chemotherapy drug: cis-diamminedichloroplatinum (II) (cisplatin). The experiments were carried out at the ID17 beamline of the European Synchrotron Radiation Facility, which produces a high-fluence monochromatic beam that is adjustable from 20 to 80 keV. Cisplatin was chosen as the carrier of platinum atoms in the cells because of its alkylating-like activity and the irradiation was done with monochromatic beams above and below the platinum K-shell edge (78.39 keV). Cell survival curves were comparable with those obtained for the same cells under conventional irradiation conditions. At a low dose of cisplatin (0.1 microM, 48 h), no difference was seen in survival when the cells were irradiated above and below the K-shell edge of platinum. Higher cisplatin concentrations were investigated to enhance the cellular platinum content. The results with 1 microM cisplatin for 12 h showed no difference when the cells were irradiated with beams above or below the platinum K-shell edge with the exception of the higher cell death resulting from drug toxicity. The intracellular content of platinum was significant, as measured macroscopically by inductively coupled plasma mass spectrometry. Its subcellular localization and particularly its presence in the cell nucleus were verified by microscopic synchrotron X-ray fluorescence. This was the first known attempt at K-shell edge photon activation of stable platinum in living cells with a platinum complex used for chemotherapy. Its evident toxicity in these cells leads us to put forth the hypothesis that cisplatin toxicity can mask the enhancement of cell death induced by the irradiation above the K-shell edge. However, K-shell edge photon activation of stable elements provides a powerful technique for the understanding of the biological effects of Auger processes. Further avenues of development are discussed.


Subject(s)
Cell Death , Cell Survival/drug effects , Cell Survival/radiation effects , Cisplatin/pharmacology , Particle Accelerators/instrumentation , Platinum/pharmacology , Radiation-Sensitizing Agents/pharmacology , X-Rays , Calibration , Cell Cycle , Cell Line , Colony-Forming Units Assay , Dose-Response Relationship, Radiation , Flow Cytometry , Head and Neck Neoplasms/radiotherapy , Humans , Photons , Tumor Cells, Cultured
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