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M C Henry-Feugeas

Publications and source records attributed to M C Henry-Feugeas.

At least 19 recordsLinked to original sources
PubMed2005

Changes in effective connectivity during incidental and intentional perception of fearful faces.

The present fMRI study examined effective connectivity within an emotional network composed of three brain areas: Amygdala (AMY), Anterior Cingulate Cortex (AAC) and Orbito-Frontal (OFC) in processing fearful faces. Two tasks: an incidental perception (gender identification) and an intentional detection (effortful discrimination) task were performed by 14 and 10 young healthy volunteers, respectively. Participants were scanned while viewing fearful, neutral and ambiguous facial expressions. Effective connectivity was assessed using Structural Equation Modeling (SEM). Results show that the hypothetical network fits the experimental data for both tasks and in both hemispheres. The comparison between Tasks 1 and 2 reveals significant differences in strength and direction of the connectivity patterns for the left and to a less stringent threshold for the right hemisphere. The path coefficients analysis suggests that the fearful information generated in AMY, reaches the OFC through the ACC in incidental perception, while in intentional perception, the route followed is in a reverse direction from OFC to ACC. Our findings confirm a differential brain connectivity between incidental and intentional processing of fearful faces.

Adult↗
PubMed2003

[Dementia: role of imaging].

This article summarizes the role of imaging in the evaluation of cognitive disorders of the elderly. The primary goal of imaging is to exclude potentially reversible dementia due to intracranial lesions such as tumor, subdural hematoma or normal pressure hydrocephalus. The value of neuroimaging in the diagnosis of degenerative disorders is then discussed: Alzheimer's disease, frontotemporal dementias, dementia with Lewy bodies, dementia associated with parkinsonian syndromes, vascular dementias and mild cognitive impairment.

Aged↗
PubMed2001

Cerebrospinal fluid flow waveforms: MR analysis in chronic adult hydrocephalus.

UNLABELLED: Henry-Feugeas MC, Idy-Peretti I, Baledent O, et al. Cerebrospinal fluid flow waveforms: MR analysis in chronic adult hydrocephalus. Invest Radiol 2001;36:146-154. RATIONALE AND OBJECTIVES: To analyze changes in cerebrospinal fluid (CSF) hydrodynamics in chronic adult hydrocephalus. METHODS: Phase-contrast cine-MR acquisitions were used to explore the ventricular system and the upper ventral cervical spaces of 16 patients. The aqueductal jet was explored in 32 control subjects. RESULTS: The duration of pulsatile caudal CSF flow (ie, CSF systole) was abnormally short in patients with active idiopathic and obstructive hydrocephalus. The duration of CSF cervical systole was normal in patients with stable hydrocephalus. The aqueductal stroke volume could be increased in stable communicating hydrocephalus. Patients who responded to shunting had shortened CSF systoles and hyperpulsatile ventricular patterns. Successful CSF diversion resulted in longer CSF systoles and CSF ventricular patterns that were no longer hyperpulsatile. CONCLUSIONS: Magnetic resonance analysis of CSF flow can show craniospinal dissociation and limitation of CSF outflow from the ventricles in both obstructive and communicating hydrocephalus; it should help determine the response to shunting in communicating hydrocephalus.

Adult↗
PubMed2001

Cerebrospinal fluid dynamics and relation with blood flow: a magnetic resonance study with semiautomated cerebrospinal fluid segmentation.

RATIONALE AND OBJECTIVES: To investigate and measure temporal and amplitude aspects of blood and cerebrospinal fluid (CSF) flow waveform relations. METHODS: A cine phase-contrast magnetic resonance imaging pulse sequence was used to measure blood and CSF flow in 16 healthy subjects aged 27 +/- 4 years. A semiautomated segmentation algorithm was developed to study CSF flow. RESULTS: Standard deviations of the aqueductal and cervical flow measurements carried out by five observers were 1% and 4%, respectively. The peak systolic arterial flow was 1087 +/- 169 mL/min, and the peak cervical CSF flush (173 +/- 59 mL/min) occurred at 5% +/- 3% of the cardiac cycle after the internal carotid systolic peak flow. Peak aqueductal flush flow (13 +/- 5 mL/min) occurred at 21% +/- 7% of the cardiac cycle after the internal carotid systolic peak flow. CONCLUSIONS: The CSF segmentation algorithm is reproducible. Brain expansion was quickly regulated by a major extracerebral CSF flush flow, whereas ventricular CSF made only a very small contribution.

Adolescent↗
PubMed2001

Imaging appearances of metastases from neuroendocrine tumours of the pancreas.

Endocrine tumours of the pancreas (ETPs) are rare neoplasms that are frequently malignant. Despite their usual slow growth, metastases do occur and have a major impact on prognosis. Metastases may be the first manifestation of disease, and recognition of particular radiological features of these hypervascular metastases should suggest their possible neuroendocrine origin. Although somatostatin receptor scintigraphy has changed the imaging strategy for these tumours and has become their principal imaging modality, radiological techniques are still required for precise localization of scintigraphic hot spots and monitoring of response to therapy. This pictorial review shows the typical radiological features of ETP metastases and emphasizes the role of different imaging modalities.

Bone Neoplasms↗
PubMed2000

Origin of subarachnoid cerebrospinal fluid pulsations: a phase-contrast MR analysis.

Cerebrospinal fluid (CSF) pulsations result from change of blood volume in the closed craniospinal cavity. We used cine phase contrast MR analysis to determine whether spinal CSF pulsations result from spinal vascular pulsations or intracranial subarachnoid pulsations, whether intracranial CSF pulsations result from intracranial large arteries pulsations or cerebrovascular bed changes. We performed a quantified physiological mapping of CSF velocity waveforms along the craniospinal axis. Thirty-six volunteers participated in the study. MR acquisitions were obtained at the intracranial level, the upper, midcervical, cervicothoracic, mid thoracic, and/or the thoracolumbar levels. The temporal velocity information were plotted as wave form and key temporal parameters were determined and analyzed; intervals from the R wave to the onset of CSF systole, to CSF systolic peak, to the end of systole, as well as duration of systole. Three kinds of dynamic channels could be differentiated along the spinal axis, the lateral, medioventral and mediodorsal channels. Lateral spinal CSF pulse waves show significant craniocaudal propagation. No such significant progression was detected through the medial channels along the spine. Through the medial channels, a cephalic progression was observed from the upper cervical level to the intracranial level. At the craniocervical junction, mediodorsal CSF systole appeared the earliest one whereas in the anterior intracranial basal cistern, CSF systole appeared delayed. In conclusion, spinal CSF pulsations seem to result mainly from intracranial pulsations in the lateral channels, whereas local vascular pulsations could modify CSF pulse wave mainly in the medial channels. At the craniocervical junction, our results suggest that blood volume change in the richly vascularised cerebellar tonsils is the main initiating factor of CSF systole; and that spinal vascular pulsations could be considered as an additional early and variable CSF pump.

Adolescent↗
PubMed2000

MRI analysis of brain atrophy after severe closed-head injury: relation to clinical status.

The purpose of this study was to determine the clinical correlates of supratentorial ventricular dilations and of corpus callosal atrophy at the subacute stage after a severe closed-head injury (CHI). Thirty-three CHI patients underwent MRI 2 months or more after injury. Morphometric measures were compared to clinical data (coma score, coma duration and Glasgow Outcome Scale). There were numerous significant correlations between clinical data and mid-third ventricle and frontal horns measurements. Fewer significant correlations were found with the lateral ventricle bodies and the corpus callosal body. There was no significant correlation with the posterior part of the corpus callosum and of the ventricles. Corpus callosum atrophy correlated significantly with anterior and deep ventricular dilatation. In conclusion, the best indicator of clinical status was ventriculomegaly, and particularly third ventricle enlargement, which probably reflects the extent of both anterior and deep white matter lesions.

Adult↗
PubMed1997

Body composition determined with MR in patients with Duchenne muscular dystrophy, spinal muscular atrophy, and normal subjects.

Magnetic resonance imaging was used to determine total fat mass of patients with neuromuscular disorders, accounting for intramuscular fat. Nineteen boys aged 9 to 12 (eight with Duchenne muscular dystrophy, three with type II spinal muscular atrophy and eight control subjects) underwent whole-body magnetic resonance imaging examination and anthropometric measurements. Whole-body fat mass was deduced from automated analysis of images normalized by a reference signal. Intramuscular and subcutaneous fat masses were deduced from manual analysis of twelve reference slices. Affected children significantly differed from control subjects for higher total fat mass, mostly related to intramuscular fat mass. Shorter protocols validated from whole-body data were shown to be more accurate than fat mass estimation derived from anthropometric measurements.

Adipose Tissue↗
PubMed1996

Screening of renal artery stenosis: assessment with magnetic resonance angiography at 1.0 T.

The results of MR angiography at 1.0 T with digital intraarterial angiography in the screening of patients with suspected renal hypertension were compared. In this first phase of the study, 10 volunteers underwent examination with both two-dimensional (2D) with traveling saturation time-of-flight (TOF) magnetic resonance angiography (MRA) with various parameters to develop a protocol for evaluation of the renal arteries. In the second phase, 36 patients with suspected renovascular hypertension underwent both 2D TOF MRA and intraarterial digital angiography to evaluate the clinical value of MRA. The degree of stenosis was graded with a two-point scale. In volunteers, using 2D acquisitions C/N ratios indicated the best flip angle as being 55 degrees (p = .02). MRA showed 100% (70/70) of all main arteries and 86% (6/7) of all accessory renal arteries seen on angiography. MRA had a sensitivity of 94% (15/16) and a specificity of 98% (60/61) for detection of stenoses of greater than 50% present in 14 patients. 2D-TOF MRA at 1.0 T shows promise in the noninvasive diagnosis of patients with suspected renovascular hypertension.

Adult↗
PubMed1996

Assessment of deep venous thrombosis in the lower limbs and pelvis: MR venography versus duplex Doppler sonography.

OBJECTIVE: This study was designed to compare the diagnostic value of MR venography and color Doppler sonography in the assessment of deep venous thrombosis. SUBJECTS AND METHODS: MR venograms and color Doppler examinations were obtained in 37 patients either with suspected deep venous thrombosis of the lower limbs or pelvis or with pulmonary embolism. Two-dimensional time-of-flight venography was used for all studies. MR and color Doppler data were collected prospectively and analyzed in a blinded manner. In a subset of 21 patients, MR venography and color Doppler sonography were prospectively compared with contrast-enhanced venography. RESULTS: When compared with contrast-enhanced venography, MR venography was 100% sensitive and 100% specific in the diagnosis of deep venous thrombosis above the knee. Color Doppler imaging depicted 13 of 15 cases of deep venous thrombosis and 5 of 6 venous examinations that had normal results, yielding a sensitivity and a specificity of 87% and 83%, respectively. The differences in sensitivity and specificity between MR venography and color Doppler sonography were not statistically significant. MR venography was 95% sensitive and 99% specific in detecting the extension of deep venous thrombosis, compared with the 46% sensitivity and 100% specificity of color Doppler sonography (differences in sensitivity, p < .01). MR images showed 29 collateral vessels, whereas only 21 were detected by contrast-enhanced venography (p < .04). CONCLUSION: MR venography seems to be more accurate than color Doppler sonography in detecting the extension of deep venous thrombosis. The positive diagnosis and extent of deep venous thrombosis can be easily detected and monitored by a noninvasive technique such as MR venography.

Adult↗
PubMed1996

[Magnetic resonance angiography of the cervical and superior mediastinal veins].

PURPOSE: To evaluate magnetic resonance venography (MRV) in the detection of cervical/mediastinal venous thrombosis (CMVT). METHODS: MR venograms were performed in 20 patients suspected for CMVT. 2D-TOF MR venography was used for all studies. MR and conventional venographic/surgical data were collected prospectively and analyzed in a blinded manner comparatively to other corroborative studies: venography (n = 8), color-Doppler studies (n = 15), CT (n = 12), and/or surgery (n = 6). RESULTS: MRV was 100% sensitive and 100% specific in the diagnosis of venous thrombosis (VT) of the cervical/mediastinal veins, present in fourteen patients, and 93% accurate in grading the extension of CMVT. MR images showed a greater number of collateral vessels than detected by contrast venography in case of complete cervical/mediastinal venous thrombosis. CONCLUSION: The positive diagnosis and extent of CMVT can be accurately diagnosed by a non-invasive method such as MRV.

Adult↗
PubMed1995

Pulmonary MR angiography at 1.0 T: early results with k-space segmented and post-contrast TurboFLASH two-dimensional time-of-flight sequences.

PURPOSE: To evaluate the combined performance of two time-of-flight methods in imaging the pulmonary arteries. MATERIALS AND METHODS: This study was prospectively conducted in 28 patients suspected for pulmonary embolism (PE). Sixteen patients were free of pulmonary vascular disease, and 12 had pulmonary vascular disease as demonstrated by pulmonary angiography. To reduce artifacts caused by cardiac and respiratory motion, MR images were acquired in all subjects using bi-dimensional (2D), gradient-recalled echo (GRE), breath-hold techniques. Sagittal thin (6-mm) sections obtained with ECG gating, k-space segmentation and incremented flip-angles (TONE), and coronal thick (15-mm) sections obtained after a unique injection of Gadolinium chelate were used. RESULTS: High quality images were obtained in all 16 (100%) subjects free of pulmonary disease with both techniques, and in 10 and 12 (87% and 100%) patients suspected for pulmonary artery disease with sagittal and coronal Gd-enhanced MRA, respectively. In patients free of pulmonary disease, TONE images exhibited distal pulmonary arteries with 2.1 subsegmental divisions on average, whereas Gd-enhanced TurboFLASH images were the most accurate to identify proximal pulmonary arteries within the mediastinum, even if only 0.8 subsegmental divisions were seen on average. A correct diagnosis of pulmonary embolism was obtained in all cases but one, with use of both MRA techniques, with an overall accuracy of 86%. CONCLUSION: The association of segmented sagittal GRE images and coronal first-pass Gd-enhanced GRE images can provide information upon normal and diseased pulmonary arteries within the mediastinum until subsegmental pulmonary branches, even in patients with short-breathing. Further studies of patients with various pulmonary artery diseases will confirm whether this technique makes pulmonary MRA feasible in clinical routine situations.

Adult↗
PubMed1995

Pulmonary time-of-flight MR angiography at 1.0 T: comparison between 2D and 3D tone acquisitions.

The purpose of this study was to compare the performance of 2D vs. 3D time-of-flight (TOF) methods in imaging the normal pulmonary arteries with commercially available 1.0 T equipment. The study was conducted in 20 volunteers and 7 patients with suspected pulmonary embolism (PE). To reduce artifacts caused by cardiac and respiratory motion, MR images were acquired in volunteers using two-dimensional (2D), gradient-recalled echo (GRE), breath-hold techniques, and three-dimensional (3D) acquisitions. Sagittal thin (6-MM) segmented k-space 2D sections obtained with cardiac gating during systole (turboFLASH, TR/TE9/6 ms, 14 segments of 9 lines) and incremented flip-angles (TONE), and 50-mm 3D volume TONE acquisitions with 32 partitions (FISP, TR/TE34/10ms) were successively performed. In the second phase of the study, patients were examined only with the 3D technique. Images of volunteers were qualitatively and quantitatively analyzed. S/N ratios were statistically compared by means of the paired-sample Wilcoxon ranked-signed test, a value of p < .05 being significant. In volunteers, 3D acquisitions displayed significantly more segment-order pulmonary arteries on average than did 2d acquisitions displayed significantly more segment-order pulmonary arteries on average than did 2D acquisitions (2.95 +/- 0.64 vs. 2.2 +/- 0.85, respectively; p < .01). Moreover, the signal intensity of arteries within the lungs was less homogeneous in the 2D than in the 3D technique, with a signal intensity ratio between peripheral and proximal arteries of 63% +/- 7% and 73% +/- 2%, respectively (p < .05). In patients, no erroneous diagnoses were obtained using the 3D technique. 3D images of normal lungs provide MR angiograms of better quality than do 2D images, and require less contribution from subjects because they are performed in free breathing. Ongoing improvements in MR sequences and further studies are now necessary to assess the value of 3D TONE MRA in the diagnosis of PE.

Adult↗
PubMed1995

Iliac artery patency before and immediately after percutaneous transluminal angioplasty: assessment with time-of-flight MR angiography.

PURPOSE: To assess the efficacy of magnetic resonance (MR) angiography of iliac arteries before and immediately after percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: In 14 patients with 22 diseased iliac artery segments (external or common), axial two-dimensional time-of-flight MR angiography was performed. Images were reconstructed with a maximum-intensity-projection (MIP) algorithm. MR angiography was performed 1-4 days after diagnostic digital angiography and 6-24 hours after PTA. Findings obtained before and immediately after PTA were compared for number and location of significant (ie, > 50%) stenoses, length and diameter of balloon to be employed, and diameter of the stenotic artery after PTA. Linear regression analysis was performed. RESULTS: Sensitivity and specificity of MR angiography for determination of significant stenoses were 95% and 97%, respectively. Before PTA, balloon dimensions depicted on MR angiograms and digital angiograms were well correlated (r = .76, P < .05). After PTA, MR angiograms and digital angiograms provided similar findings in all but one case. CONCLUSION: MR angiography helped determine if PTA is indicated and depicted iliac artery patency after PTA.

Adult↗
PubMed1995

[The diagnosis of primary cerebral lymphoma in AIDS. The contribution of imaging].

Apart from the very frequent HIV encephalitis, which lays the foundation for opportunistic infections, the most common diseases encountered in HIV-infected patients are toxoplasmosis and lymphoma; the percentage of cases of other diseases is very small. It is capital to diagnose cerebral lymphoma at an early stage in these patients who already are in a precarious general and neurological state since this type of lesion usually occurs late in the natural course of AIDS. In the differential diagnosis between toxoplasmosis and lymphoma only stereotaxic biopsy enables a positive diagnosis to be made, but imaging methods, such as CT and MRI, provide data that help guide to a diagnosis which sometimes may be definitive. Suggestive of lymphoma is a single infiltrating lesion wider than 4 cm, which is paraventricular or located in the posterior fossa, has little perilesional alteration and a short tumoral doubling time during the imaging follow-up. Suggestive of toxoplasmosis are multiple, small, annular or nodular lesions with an important perilesional inflammation and usually located in basal ganglia. In addition, in MRI the kinetics of enhancement after contrast injection is intense and occurs early in lymphoma, in contrast with the toxoplasmic abscesses, and this should provide a more specific differential diagnosis. Scintigraphic studies with somatostatin or positron emission tomography, using fluorodeoxyglucose (FDG-PET scintigraphy), also seem to be an interesting mean of making a specific diagnosis of cerebral lesion, according to a principle that is close to dynamic MRI. In lymphoma, capturing of the tracer is about 3 times greater than in infective lesions, notably the toxoplasmic ones. Imaging, therefore, is provided with tools which permit an increasingly specific approach to the primary cerebral lymphoma of AIDS, the definitive diagnosis of which rests on stereotaxic biopsy. This high specificity facilitates a better selection of patients requiring this procedure and shortens the delay in its execution.

AIDS-Related Opportunistic Infections↗
PubMed1994

MR imaging of posteromedial and posterolateral stabilisers of the knee: anatomic basis and patterns of lesions in knee injuries.

The angular points are the ligamentous and tendinous structures that reinforce the posteromedial and posterolateral capsule of the knee and share in fixation of the posterior horns of the menisci. They are often damaged in acute injuries and this is usually associated with ruptures of the cruciate and collateral ligaments and may add to the degree of laxity. We describe the normal appearance of these structures in terms of the sectional anatomy, correlated with the lesional appearances of complete and incomplete ruptures and associated meniscal detachments as shown by clinical testing and arthrotomy findings.

Collateral Ligaments↗
PubMed1993

Temporal and spatial assessment of normal cerebrospinal fluid dynamics with MR imaging.

The purpose of this study was to measure normal cerebrospinal fluid (CSF) pulsations within the intracranial and upper cervical subarachnoid spaces and the ventricular system. Phase contrast cine MR sequences were performed in sagittal and axial planes on 13 volunteers with flow encoding in the craniocaudal direction. CSF pulsations displayed considerable variations in healthy subjects, depending both on measurements localization and subjects, with CSF peak velocities ranging from 0 to 7 cm/s. In the subarachnoid spaces, the highest velocities occurred in the anterior location and increased from the cerebellar pontine angle cisterns towards the lower cervical spaces. In the ventricular system, the highest velocities occurred through the aqueduct of Sylvius. CSF flow within the third ventricle seemed to reflect a circular motion. There was a caudal net CSF flow in the aqueduct whereas in the upper cervical spaces net CSF flow was caudal anteriorly and cranial laterally. Velocity profiles of CSF pulsations demonstrated arterial morphology. After the R wave, caudal systolic motion was first observed in the posterior subarachnoid spaces, soon after in the anterior subarachnoid spaces and later in the ventricular system. Considering the morphology of CSF pathways, three successively initiated phenomena may explain the temporal course of CSF motion: the systolic expansion of the main arteries at the base of the brain, the systolic expansion of the cerebrospinal axis and, finally, the systolic expansion of the choroid plexuses.

Adult↗