Isolated shoulder palsy due to cortical infarction: localisation and electrophysiological correlates of recovery.
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Aged↗
Biomedical subjects
M Caulo
Publications and source records attributed to M Caulo.
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↗
Long-term effects of stroke on neuronal rest activity in rolandic cortical areas.
To understand the relationship between neuronal function and clinical state in the framework of stroke, the long-term poststroke rolandic spontaneous neuronal activity was studied by means of magnetoencephalography. Fifty-six patients who had suffered a unilateral stroke within the middle cerebral artery were enrolled. Median time since stroke was 2.8 years. In association with lesion features and clinical picture, total and relative band powers and the spectral entropy were analyzed in the affected (AH) and unaffected (UH) hemispheres in comparison with an age-matched control group. An increase of absolute and relative slow band powers and a reduction of relative fast band powers were found in patients' AH with respect to both UH and control values. Absolute delta band was higher than in controls also in UH. New findings were the increase of rolandic rest activity power also in the alpha band and the decrease of spectral entropy in AH with respect to both UH and control values. Moreover, our results in chronic stroke patients indicate frequency-selective alterations related to specific dysfunctions: global clinical status was mostly impaired in patients with larger lesions and increased total and slow band activity powers, whereas hand functionality was mostly disrupted in patients with subcortical involvement and reduction of high-frequency rhythms and spectral entropy. Total power increase and spectral richness decrease are in agreement with a higher synchrony of local neuronal activity, a reduction of the intracortical inhibitory network's efficiency, and an increase of neuronal excitability.
Adolescent↗
Mononeuropathy following subcutaneous interferon-beta injection.
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Adult↗
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↗
Unusual ipsilateral hyperkinetic automatisms in SMA seizures.
PURPOSE: To describe repetitive movements of the right arm possibly originating from the ipsilateral SMA area in two drug-resistant epileptic patients. METHODS: Two epileptic patients (one female, one male, 35 and 36 years old, respectively) were submitted to pre-surgical evaluation including history, neurological examination, long-term video-EEG monitoring, interictal and ictal SPET, MRI and fMRI, neuropsychological assessment. Invasive recordings (stereoelectroencephalography) were also performed. RESULTS: In both patients ictal semiology was characterized by very stereotyped repetitive right arm movements, i.e. tapping towards the thorax (movement rate of 6-7 Hz and 3-4 Hz for the two subjects, respectively). Seizures in the first patient, whose epilepsy was cryptogenetic, originated from the right pre-SMA area, which was surgically removed. She is seizure free 2 years after the operation. In the second patient, in whom a right pre-frontal post-abscess porencephaly was disclosed, the epileptogenic zone included the lesion and surrounding areas, while the SMA area was involved less consistently. CONCLUSIONS: Even if, according to literature, SMA epilepsy is predominantly characterized by postural manifestations, ipsilateral repetitive movements could be a relevant sign in this kind of epilepsy, as showed in our first patient. The presence of similar semiology in the second patient, might suggest that the symptomatogenic zone involved SMA area.
Adult↗
Does cerebrovascular disease affect the coupling between neuronal activity and local haemodynamics?
The relationship between neurophysiological and cerebrovascular-metabolic findings in patients affected by severe cerebrovascular deficits was investigated by comparing magnetoencephalographic (MEG-evoked fields) and blood oxygen level-dependent functional MRI (BOLD fMRI) responses to median nerve electric stimulation. Despite the use of identical stimuli, the two techniques elicited always-detectable responses in the control group (10 subjects), but demonstrated uncorrelated activation properties in our patient sample (10 subjects). All patients showed clear MEG signals in both the affected and unaffected hemispheres, indicating well synchronized, stimulus-locked firing of neurons in the primary sensorimotor cortex, but some patients showed no fMRI activation in either the affected or the unaffected hemisphere. In order to clarify the origin of this uncoupling, we investigated the possible role of lesion site, white matter hyperintensities, current medication, risk factors, anatomy of the neck vessels, and cerebral vasomotor reactivity (VMR) as measured by transcranial Doppler (TCD) during CO2 inhalation. Neither neuronal activation properties nor any of the considered factors were related to the lack of fMRI activation, with the exception of altered vasomotor reactivity, which was, on the contrary, strongly related. Preserved VMR was paired with absent BOLD bilaterally in the only patient affected by microangiopathy. This finding suggests that BOLD contrast could be more sensitive than TCD to chronic microvascular impairments, measuring small- rather than large- vessel reactivity.
Adult↗
Neuroradiological findings in two cases of isolated amyloidoma of the central nervous system.
Neuroradiological findings in two cases of isolated cerebral amyloidoma are reported. Case 1: A 15-year-old male admitted because of left jacksonian seizure. Case 2: A 31-year-old man admitted because of temporal seizures. In both patients, CT scans showed spontaneously hyperdense and enhancing nodules. On MRI, lesions displayed signals isointense with surrounding edema on T1-weighted sequences and mildly hypointense on T2-weighted sequences if compared with edema; peripheral contrast enhancement after gadolinium administration was present. Histopathological examination of both specimens revealed the presence of acellular eosinophilic hyalinized material consistent with amyloid, forming confluent nodular masses in the white and gray matter.
Adolescent↗
Soft tissue liposarcoma: histological subtypes, MRI and CT findings.
PURPOSE: Liposarcoma is the second most common malignancy of soft tissues. The commonly accepted classification of liposarcoma includes five basic histological categories: well-differentiated, myxoid, round cell, dedifferentiated and pleomorphic liposarcoma. The clinical behaviour of liposarcoma closely reflects its histological appearance, so that to identify the histological subtypes is very important for both prognosis and therapy. The aim of this study was to ascertain whether the histological features of liposarcoma subtypes can be correlated with MRI (Magnetic Resonance Imaging) and CT (Computed Tomography) findings by retrospectively evaluating nineteen cases of histologically-proved liposarcoma. MATERIALS AND METHODS: The MRI examinations performed over the past eight years on nineteen patients affected by liposarcoma were retrospectively reviewed. All patients underwent ultrasound and MRI examination; T2 and T1-weighted sequences were available in all cases and fat-saturated sequences in 4 cases; all patients were administered paramagnetic contrast material. CT scans were obtained in twelve patients. All patients had a biopsy, surgical resection and histology. RESULTS: The study group had 7 well-differentiated, 8 myxoid, 3 pleomorphic and 1 round cell liposarcoma. Well-differentiated liposarcomas had largely lipomatous appearance on both CT and MRI, typically with septa and areas showing high signal intensity on T2w MR images and low signal intensity on T1w images, and slightly hypodense compared to the muscle in CT, representing the sarcomatous areas. Myxoid liposarcomas were mildly heterogeneous with typical high signal intensity on T2w images and isointense to the muscle in T1w images, with lacy or linear septa of fatty tissue in six cases. The pleomorphic and round-cell subtypes demonstrated marked heterogeneity on MR images, with areas of necrosis and heterogeneous contrast enhancement, indistinguishable from other high-grade sarcomas. DISCUSSION AND CONCLUSIONS: Well-differentiated liposarcoma may be distinguished from other types of liposarcoma by its largely lipomatous appearance. Myxoid liposarcoma may be distinguished on the basis of its homogeneous or mildly heterogeneous structure due to the large amounts of the extracellular myxoid material that give it its typical MR appearance. Both well-differentiated and myxoid liposarcomas, the most common types accounting for about 50% of all liposarcomas, have a more favourable clinical behaviour than the other histological types. Differentiation of these from the other histological types of liposarcoma therefore has a high significance for prognosis and therapeutical approach. On the basis of our experience and of the literature, we believe that diagnostic imaging and in particular the MR examination may lead to a correct diagnosis.
Adult↗
Acquired inflammatory white matter disease.
OBJECTS: During the last decades there have been various attempts to define the characteristics of white matter inflammatory diseases. Most of the authors concerned agree in considering Schilder's myelinoclastic diffuse sclerosis (SD), Devic's neuromyelitis optica (NMO) and Balo's concentric sclerosis to be variants of typical multiple sclerosis (MS). Moreover, in childhood even typical MS presents more aggressive behaviour, with frequent evidence of giant, tumefactive, necrotic or haemorrhagic plaques. METHODS: The authors review the literature and cite atypical cases that appear to be intermediate between MS and SD, NMO and SD. CONCLUSIONS: Finally, some critical revisions are proposed concerning cases with clinical presentation, history, laboratory and MR findings intermediate between those of acute disseminated encephalomyelitis and of MS.
Brain↗
[Staging and re-staging of soft tissue sarcoma using MRI. Usefulness of contrast media].
PURPOSE: This study aims to evaluate the usefulness of paramagnetic contrast medium (Gadolinium) in the staging and re-staging of soft tissue tumors using Magnetic Resonance Imaging (MRI). MATERIAL AND METHODS: Sixty patients affected by soft tissue sarcoma of different histotype were retrospectively evaluated. Age ranged from 23 to 78 years. Data were obtained from the musculoskeletal tumor database of our Department of Radiology and cases from the last 7 years (1993-1999) entered this study. All the patients were submitted to ultrasound (US) and to routine and enhanced MR examinations (SE T1-weighted and Fast-SE T1 and T2-weighted before and after fat saturation pulse; GE T2-weighted sequences). At least two different scan planes were obtained depending on the major axis of the lesion. Once imaging information had been obtained all the patients underwent surgery and histology. After surgery, the mean follow-up period was 18 months. Paramagnetic contrast medium (0,2mmol/Kg) was administered in all the MR follow-up examinations. RESULTS: Lesions included adipose histology in 15 cases; muscular histology in 12 cases; fibro-hystiocitic histology in 20 cases; synovial histology in 8 cases; mixed histology in 5 cases. Excluding lesions with mainly adipose content showing obvious high signal intensity on T1-weighted sequences, the other lesions rarely presented MR features specific to histological category also after contrast medium administration. In all the cases MRI allowed an accurate definition of the lesion boundaries to exclude or demonstrate neighbor region invasion. In 11 cases, MRI was able to demonstrate the presence of a recurrent tumor. In 2 out of 11 cases, recurrences were detected out only after intravenous administration of Gadolinium, plain MRI having failed to recognize them. DISCUSSION AND CONCLUSIONS: Despite the absence of specific MRI signs of the different soft tissue tumor histotypes also after Gadolinium administration, MRI remains the best imaging technique to establish the exact morphology of the lesions and to establish the invasion of the neighbor regions by the tumors. The presence of regional spreading of the tumor has to be considered a sign of malignancy. During the follow-up, the use of Gadolinium allows the MR examinations to reach high sensitivity levels and makes it also possible to recognize local recurrences of a very small size. Considering our experience we recommend, whenever a follow-up of resected soft tissue tumors is requested, to perform MRI examination before and after intravenous Gadolinium administration.
Adult↗
Cerebral amyloid angiopathy presenting as nonhemorrhagic diffuse encephalopathy: neuropathologic and neuroradiologic manifestations in one case.
A case of cerebral amyloid angiopathy is presented with MR imaging findings of high intense signal on T2-weighted sequences at the level of the white and gray matter of both hemispheres in the absence of neuroradiologic signs of cerebral hemorrhage. The biopsy specimen revealed deposition of amyloid in the walls of the intracranial arterial branches and focal ischemic changes and gliosis in the gray and white matter. We consider this presentation to be very unusual in patients affected by cerebral amyloid angiopathy.
Adult↗