Isolated shoulder palsy due to cortical infarction: localisation and electrophysiological correlates of recovery.
Explore the source record for details and available documents.
Aged↗
Biomedical subjects
A Tartaro
Publications and source records attributed to A Tartaro.
Somatotopy of anterior cingulate cortex (ACC) and supplementary motor area (SMA) for electric stimulation of the median and tibial nerves: an fMRI study.
In this study, we tested whether there is a somatotopic sensory organization in human anterior cingulate cortex (ACC) and supplementary motor area (SMA), as a reflection of central feed-back sensory processing for motor control. To this aim, fMRI recordings were performed in 15 normal young adults during nonpainful and painful electric stimulation of median nerve at the wrist and tibial nerve at the medial malleolus. Results showed that the representation of median nerve area was more anterior in the ACC and more inferior in the SMA than the one of tibial nerve area. This was true for both nonpainful and painful stimulation intensities. These results point to a somatotopic sensory organization of human ACC and SMA.
Adult↗
"What" versus "where" in the audiovisual domain: an fMRI study.
Similar "what/where" functional segregations have been proposed for both visual and auditory cortical processing. In this fMRI study, we investigated if the same segregation exists in the crossmodal domain, when visual and auditory stimuli have to be matched in order to perform either a recognition or a localization task. Recent neuroimaging research highlighted the contribution of different heteromodal cortical regions during various forms of crossmodal binding. Interestingly, crossmodal effects during audiovisual speech and object recognition have been found in the superior temporal sulcus, while crossmodal effects during the execution of spatial tasks have been found over the intraparietal sulcus, suggesting an underlying "what/where" segregation. In order to directly compare the specific involvement of these two heteromodal regions, we scanned ten male right-handed subjects during the execution of two crossmodal matching tasks. Participants were simultaneously presented with a picture and an environmental sound, coming from either the same or the opposite hemifield and representing either the same or a different object. The two tasks required a manual YES/NO response respectively about location or semantic matching of the presented stimuli. Both group and individual subject analysis were performed. Task-related differences in BOLD response were observed in the right intraparietal sulcus and in the left superior temporal sulcus, providing a direct confirmation of the "what-where" functional segregation in the crossmodal audiovisual domain.
Acoustic Stimulation↗
Functional MRI study of diencephalic amnesia in Wernicke-Korsakoff syndrome.
Anterograde amnesia in Wernicke-Korsakoff syndrome is associated with diencephalic lesions, mainly in the anterior thalamic nuclei. Whether diencephalic and temporal lobe amnesias are distinct entities is still not clear. We investigated episodic memory for faces using functional MRI (fMRI) in eight controls and in a 34-year-old man with Wernicke-Korsakoff syndrome and diencephalic lesions but without medial temporal lobe (MTL) involvement at MRI. fMRI was performed with a 1.5 tesla unit. Three dual-choice tasks were employed: (i) face encoding (18 faces were randomly presented three times and subjects were asked to memorize the faces); (ii) face perception (subjects indicated which of two faces matched a third face); and (iii) face recognition (subjects indicated which of two faces belonged to the group they had been asked to memorize during encoding). All activation was greater in the right hemisphere. In controls both the encoding and recognition tasks activated two hippocampal regions (anterior and posterior). The anterior hippocampal region was more activated during recognition. Activation in the prefrontal cortex was greater during recognition. In the subject with Wernicke-Korsakoff syndrome, fMRI did not show hippocampal activation during either encoding or recognition. During recognition, although behavioural data showed defective retrieval, the prefrontal regions were activated as in controls, except for the ventrolateral prefrontal cortex. fMRI activation of the visual cortices and the behavioural score on the perception task indicated that the subject with Wernicke-Korsakoff syndrome perceived the faces, paid attention to the task and demonstrated accurate judgement. In the subject with Wernicke-Korsakoff syndrome, although the anatomical damage does not involve the MTL, the hippocampal memory encoding has been lost, possibly as a consequence of the hippocampal-anterior thalamic axis involvement. Anterograde amnesia could therefore be the expression of damage to an extended hippocampal system, and the distinction between temporal lobe and diencephalic amnesia has limited value. In the subject with Wernicke-Korsakoff syndrome, the preserved dorsolateral prefrontal cortex activation during incorrect recognition suggests that this region is more involved in either the orientation or attention at retrieval than in retrieval. The lack of activation of the prefrontal ventrolateral cortex confirms the role of this area in episodic memory formation.
Adult↗
Human brain activation during passive listening to sounds from different locations: an fMRI and MEG study.
Recent animal and human studies indicate the existence of a neural pathway for sound localization, which is similar to the "where" pathway of the visual system and distinct from the sound identification pathway. This study sought to highlight this pathway using a passive listening protocol. We employed fMRI to study cortical areas, activated during the processing of sounds coming from different locations, and MEG to disclose the temporal dynamics of these areas. In addition, the hypothesis of different activation levels in the right and in the left hemispheres, due to hemispheric specialization of the human brain, was investigated. The fMRI results indicate that the processing of sound, coming from different locations, activates a complex neuronal circuit, similar to the sound localization system described in monkeys known as the auditory "where" pathway. This system includes Heschl's gyrus, the superior temporal gyrus, the supramarginal gyrus, and the inferior and middle frontal lobe. The MEG analysis allowed assessment of the timing of this circuit: the activation of Heschl's gyrus was observed 139 ms after the auditory stimulus, the peak latency of the source located in the superior temporal gyrus was at 156 ms, and the inferior parietal lobule and the supramarginal gyrus peaked at 162 ms. Both hemispheres were found to be involved in the processing of sounds coming from different locations, but a stronger activation was observed in the right hemisphere.
Acoustic Stimulation↗
Topographic organization of the human primary and secondary somatosensory cortices: comparison of fMRI and MEG findings.
We studied MEG and fMRI responses to electric median and tibial nerve stimulation in five healthy volunteers. The aim was to compare the results with those of a previous study using only fMRI on the primary and secondary somatosensory cortices in which the somatotopic organization of SII was observed with fMRI. In the present work we focus on the comparison between fMRI activation and MEG equivalent current dipole (ECD) localizations in the SII area. The somatotopic organization of SII was confirmed by MEG, with the upper limb areas located more anteriorly and more inferiorly than the lower limb areas. In addition a substantial consistency of the ECD locations with the areas of fMRI activation was observed, with an average mismatch of about 1 cm. MEG ECDs and fMRI activation areas showed comparable differences in SI.
Adult↗
Diagnostic utility of an echo-contrast agent in patients with synovitis using power Doppler ultrasound: a preliminary study with comparison to contrast-enhanced MRI.
The purpose of this study was to first evaluate Levovist (Schering, Berlin, Germany), an echo-contrast agent, during power Doppler sonography (PDS) in patients with synovitis using asymptomatic joints as controls. Then we evaluated the accuracy of this technique against contrast-enhanced MRI. Forty patients (19 men and 21 women; mean age 40 years) were enrolled on the basis of clinical signs, laboratory tests, and radiographic findings positive for articular inflammatory disease. They were examined with conventional ultrasonography (US) and PDS techniques before and after intravenous contrast medium injection. Fourteen patients then underwent MRI with and without contrast medium 8-14 days after PDS studies. Three expert readers independently evaluated each examination. After contrast medium, synovium in inflammatory arthritis enhanced on PDS compared with normal joints in the same patient. Power Doppler sonography after contrast medium and MRI were concordant in all cases. Power Doppler sonography with contrast medium showed a qualitative increase in signal from synovial vessels, the first sign of synovial changes in inflammatory diseases.
Adolescent↗
Topographic organization of the human primary and secondary somatosensory areas: an fMRI study.
The topographical organization of SI and SII somatosensory areas was investigated using fMRI at 1.5 T and electrical sensory stimulation. Electrical stimuli were delivered unilaterally to the median nerve at the wrist and to the tibial nerve at the medial malleolus, during a block paradigm study. In all subjects, activation was observed, contralaterally to the stimulated side, in the post-central gyrus, in the posterior parietal cortex, in the mesial pre-frontal region and, bilaterally, in the supratemporal region at the level of the Sylvian fissure. The latter region, corresponding presumably to SII, showed a rough but clearcut topographical organization, with the median nerve areas located more posteriorly. In addition, weaker activations were observed in some subjects in the ipsilateral mesial prefrontal region and in the ipsilateral posterior parietal cortex. Information contained in the present study represent an interesting database for future investigations on the effects of sensorimotor learning in normal individuals on plastic reorganization following a lesion of the primary sensorimotor centers, i.e. in stroke patients, on the topography and balance between upper and lower limb representations in primary and secondary somatosensory cortices.
Adult↗
Frontal lobe syndrome reassessed: comparison of patients with lateral or medial frontal brain damage.
Examination of mood and behaviour changes after frontal damage may contribute to understanding the functional role of distinct prefrontal areas in depression and anxiety. Depression and anxiety disorders, symptoms, and behaviour were compared in eight patients with single lateral and eight patients with single medial frontal lesions matched for age, sex, race, education, socioeconomic status, side, and aetiology of lesion 2 weeks and 3 months after brain injury. DSM IV major depressive and generalised anxiety disorders were more frequent in patients with lateral compared with medial lesions at 2 weeks but not at 3 months. At 3 months, however, patients with lateral damage showed greater severity of depressive symptoms, and greater impairment in both activities of daily living and social functioning. At initial evaluation depressed mood and slowness were more frequent, whereas at 3 months slowness, lack of energy, and social unease were more frequent in the lateral than the medial group. Patients with lateral lesions showed greater reduction of emotion and motivation (apathy) during both examinations. Medial frontal injury may fail to produce emotional dysregulation or may inhibit experience of mood changes, anxiety, or apathy. Lateral prefrontal damage may disrupt mood regulation and drive while leaving intact the ability to experience (negative) emotions.
Activities of Daily Living↗
Long echo time STIR sequence MRI of optic nerves in optic neuritis.
MRI of the optic nerves was obtained in 13 patients with acute optic neuritis and 13 with a previous optic neuritis (ON), assessed by clinical features, visual fields and visual evoked potentials. Results of the conventional short tau inversion recovery (STIR) sequence obtained with a short echo time (STE-STIR; 22 ms) were compared with those of a long echo time (LTE-STIR: 80 ms) sequence. The conventional STE-STIR sequence revealed lesions in the optic nerves in 78.5% of acute and 58.8% of previous ON. The LTE-STIR sequence showed abnormalities in 92.8% of acutely symptomatic nerves and 94.1% of nerves with previous ON. The optic nerve lesions appeared significantly longer with the LTE-STIR sequence than with the conventional STE-STIR sequences, in both acute and previous ON.
Adult↗
Long time echo STIR sequence magnetic resonance imaging of optic nerves in optic neuritis.
Magnetic resonance images of optic nerves were obtained in 20 patients with acute optic neuritis (ON), and assessed by means of clinical, visual field and visual evoked potential evaluations; the imaging was repeated 1 year later. The results of the conventional Short Tau Inversion Recovery (STIR) sequence obtained using short time echo (STE-STIR: 22 msec) were compared with those of the long time echo sequence (LTE-STIR: 80 msec). The conventional STE-STIR sequence revealed lesions in 57.2% cases of acute ON and in 42.9% of the optic nerves affected by previous ON; the LTE-STIR sequence was diagnostic in 95.2% of acute ON cases and in 85% of patients with previous ON. The calculated length of the optic nerve lesions was significantly longer in the images obtained using the LTE-STIR sequence than in those obtained using conventional STE-STIR sequences.
Adult↗
Long time echo stir sequence magnetic resonance imaging of optic nerves in optic neuritis.
Magnetic resonance imaging of optic nerves was obtained in 13 patients with acute optic neuritis and in 13 patients with a previous history of optic neuritis (ON), assessed by clinical, visual fields and visual evoked potentials evaluations. Results of the conventional short tau inversion recovery (STIR) sequence obtained with short time echo (STE-STIR: 22 ms) were compared with long time echo (LTE-STIR: 80 ms) sequence. The conventional STE-STIR sequence revealed lesions in 78.5% of acute ON and in 58.8% of optic nerves affected by previous ON. The LTE-STIR sequence was diagnostic in 92.8% of acutely symptomatic nerves, in 94.1% of nerves with previous ON. The calculated length of optic nerve lesions was significantly longer in imaging obtained with the LTE-STIR sequence than with the conventional STE-STIR sequences, both in acute and previous ON.
Adult↗
Preoperative spinal angiography for lateral extracavitary approach to thoracic and lumbar spine.
Explore the source record for details and available documents.
Angiography↗
[Renal arteries: angiography with TOF 3D magnetic resonance with and without contrast media (Gd-DTPA)].
This work was aimed at investigating the value of Gd-DTPA to demonstrate distal renal artery branches with 3D TOF Magnetic Resonance angiography (MRA). Ten volunteers and two patients with proximal-distal renal artery stenoses were studied with MRA; all subjects were studied before and after Gd-DTPA. MRA was performed with a 1.5-T superconductive magnet (Magnetom Siemens); the FISP 3D sequence was used with the following setting: FA 25 degrees, TR 40 ms, TE 6 ms, slice thickness 64 mm with 64 partitions and MA 256 x 256. This setting was not changed from pre- to post-contrast scans. The images acquired on the z axis were rotated, according to the MIP, on the axial and the sagittal axes, from 0 degrees to 180 degrees, with a 15 degrees step. 0.2 ml/kg of Gd-DTPA were injected as bolus during 3D acquisitions; the injection was started half-way through acquisition. To evaluate and compare pre- and post-contrast MRA images, the signal-to-noise (S/N) ratio and the demonstration of the various renal artery segments were studied. Average S/N ratio was 2.3 in the right renal artery and 2.1 in the left renal artery on pre-contrast MRA images, while it was 0.9 in the left renal artery and 0.8 in the right renal artery on post-contrast MRA images. These differences were statistically significant (p < 0.01). As for the demonstration of the distal segments and of the bifurcations, enhanced MRA was no better than unenhanced MRA. As for the demonstration of distal segment stenoses, enhanced MRA proved no better than unenhanced MRA in both patients. To conclude, in our experience MRA after Gd-DTPA failed to allow the systematic demonstration of the distal segments and of the bifurcations of the renal arteries.
Adult↗
Abnormal length of respiratory cilia in a pig. An ultrastructural study.
The authors report the first case of abnormal length of respiratory cilia in a domestic animal (18 microns versus normal length about 5 microns). These cilia lie on the carpet of cilia of normal length. The width of some of these cilia is also abnormal, measuring 0.5-0.6 microns. Other cilia have hook-shaped tips that could be responsible for an effective beat. We suggest that the ineffective ciliary beat could also be due to the undulating movements of abnormally long cilia, and stress the need for further morphological and biochemical studies of respiratory cilia in pigs. Respiratory pathology is a very common finding in pigs and is responsible for remarkable economical losses.
Animals↗
Magnetic resonance angiography compared with basic magnetic resonance in intracranial vascular diseases.
The diagnostic value of magnetic resonance angiography (MR-Angio) in the study of intracranial vascular diseases was compared with that of basic magnetic resonance (MR) in 35 patients presenting with a total of 45 pathologies (13 vascular malformations, 17 aneurysms, 3 vascular stenoses, all also examined by standard angiography, and 12 cases of dolichobasilar artery). A joint reading of the results was carried out by two radiologists who evaluated the basic MR and MR-Angio separately and thereafter filled in a fixed-choice answer form. In the author's opinion, MR-Angio may be considered a complementary technique to basic MR, offering a greater capacity for identification and characterization of these intracranial lesions. In vascular malformations and aneurysms, MR-Angio may be performed as a preliminary to digital subtraction angiography.
Aneurysm↗
MRI alterations as an early finding in Creutzfeld-Jakob disease.
Two cases of Creutzfeldt-Jakob Disease (CJD) are reported. In both cases, pathologically confirmed, magnetic resonance imaging (MRI) showed bilateral altered signal areas in the basal ganglia, early in the course of the disease. The CT scan, although performed later than MRI, confirmed these findings. Only in one patient did electroencephalography (EEG) show typical triphasic sharp-waves, but this support to clinical diagnosis was obtained 1 month after the appearance of MRI alterations.
Brain↗
[Whole body MR angiography. Physiologic presaturation++ of the inferior vena cava].
Whole-body MRA, performed with the time-of-flight (TOF) technique requires presaturation pulses adequately positioned and to eliminate the arterial and/or venous signal (FRODO technique: "Flow Respiratory artifact Obliteration with Directed Orthogonal pulses"). Additional presaturation pulses involve an increase in the radiofrequency dose absorbed by the patient, frequently over 0.4 watt x kg, which is the threshold absorption per kg. In the present paper, the possible saturation of caval system exploiting the modulation of apnea in whole-body MRA was investigated. Ten volunteers and 10 patients with different diseases were studied. All subjects underwent abdominal MRA with the TOF 2D (FA 18 degrees, TR 22 ms, TE 10 ms) technique. Images were acquired with three modulations of apnea: maximum inspiration, expiration, Müller maneuver. With respect to the anteroposterior diameter of inferior vena cava in inspiration, the inferior cava was reduced by 21.7% in expiration and by 35.7% in Müller maneuver. The lower caliber of vena cava allowed selective angiogram of the aorta. Expiration maneuvers are suggested as an alternative to caval flow saturation by the FRODO technique. As for expiration maneuvers, the volunteers and patients studied preferred to modulate the apnea in forcible expiration. Müller maneuver, through more effective (in 4 cases total caval collapse was obtained) is nonetheless more difficult.
Aorta, Abdominal↗