Biomedical subjects

D Perani

Publications and source records attributed to D Perani.

At least 91 records · Page 5Linked to original sources

PubMed1990

In vivo metabolism and kinetics of 99mTc-HMPAO.

The cerebral distribution of 99mTc-labeled d, l, hexamethyl-propylene-amine-oxime (99mTc-HMPAO) as a function of rCBF and time was examined in rats and in man. The results of this study confirm that 99mTc-HMPAO is distributed in brain in proportion to rCBF. However, the rapid systemic breakdown of the tracer in blood results in considerable difficulties in the assessment of the arterial concentration of the parent compound; incomplete extraction of 99mTc-HMPAO from blood to brain and significant efflux from brain represent further limitations in the use of this tracer for quantification of rCFB. Despite these limitations 99mTc-HMPAO is of potential interest for a qualitative assessment of rCBF in specific clinical conditions.

Animals↗

PubMed1990

Cerebral blood flow, blood volume and oxygen utilization. Normal values and effect of age.

Regional cerebral blood flow (CBF), oxygen extraction ratio (OER), oxygen utilization (CMRO2) and blood volume (CBV) were measured in a group of 34 healthy volunteers (age range 22-82 yrs) using the 15O steady-state inhalation method and positron emission tomography. Between subjects CBF correlated positively with CMRO2, although the interindividual variability of the measured values was large. OER was not dependent on CMRO2, but highly negatively correlated with CBF. CBV correlated positively with CBF. When considering the values of all the regions of interest within a single subject, a strict coupling between CMRO2 and CBF, and between CBF and CBV was found, while OER was constant and independent of CBF and CMRO2. In 'pure' grey and white matter regions CMRO2, CBF and CBV decreased with age approximately 0.50% per year. In other regions the decline was less evident, most likely due to partial volume effects. OER did not change or showed a slight increase with age (maximum in the grey matter region 0.35%/yr). The results suggest diminished neuronal firing or decreased dendritic synaptic density with age.

Adult↗

PubMed1989

Cortical pathophysiology and clinical neurologic abnormalities in acute cerebral ischemia. A serial study with single photon emission computed tomography.

We studied brain cortical radioactive tracer activity in a consecutive series of nine patients with acute hemispheric ischemic stroke at their first cerebral ischemic stroke at their first cerebral ischemic episode. Results from N,N,N'-trimethyl-N'- (2-hydroxy-3-methyl-5-[123-I]-iodobenzyl)-1,3 propanediamine-2HCl (four patients) and technetium Tc 99m hexamethylpropyleneamine oxime (five patients) single photon emission computed tomographic studies were compared with x-ray computed tomography (CT) and clinical findings within the first 48 hours, on day 10, and on day 30 after the clinical ictus. Cortical hypoactivity agreeing with the clinical findings was found on all initial scans but not in the follow-up studies. Cortical activity on the affected side in patients with stroke was significantly lower when compared with cortical activity in sex- and age-matched controls (n = 21). Computed tomography (with contrast) was less sensitive in detecting the ischemic lesions. These studies demonstrate that in the acute phase of stroke there is a single photon emission computed tomographic cortical disturbance that agrees with clinical findings, even when computed tomography scan infarction is limited to subcortical structures.

Adult↗

PubMed1988

Crossed aphasia: functional studies with single photon emission computerized tomography.

The correlation between clinical picture, CT scan and regional cerebral blood flow (rCBF) assessed by single photon emission computerized tomography (SPECT) was investigated in two patients with crossed aphasia. The presence and degree or right hemisphere dysfunction, beyond the areas affected by CT, closely paralleled the time course of language disturbances in both patients: transient aphasia in case 1 was associated with temporary reduction of perfusion in the right hemisphere, while in case 2 persistent aphasia and apraxia were found along with severe right hemisphere hypoperfusion three year after the onset of stroke.

Aged↗

PubMed1988

Remote effects of subcortical cerebrovascular lesions: a SPECT cerebral perfusion study.

The remote effects of small unilateral cerebrovascular lesions confined to subcortical structures were evaluated by single photon emission computerized tomography (SPECT) and a CBF tracer, I-123 HIPDM. A CBF study was performed in 34 patients presenting with subcortical stroke either in the acute or in the chronic stages. Twenty-one of the 34 patients showed areas of cortical hypoperfusion ipsilateral to the subcortical lesion. In 14 patients, asymmetry of perfusion was also observed at the cerebellar level, perfusion being significantly reduced in the cerebellar hemisphere contralateral to the lesion. There was no correlation between the degree and extension of these remote effects and the type of stroke (ischemic or hemorrhagic), the patency of cerebral arteries, or the size and site of the lesion by transmissive computerized tomography (TCT). Subcortical hematomas showed a correlation between occurrence of remote effects and time interval from the onset of stroke, occurring more frequently in the acute phase. A correlation was observed between cortical and cerebellar remote effects and the severity of clinical presentation. The causes of remote effects are still unclear and have been extensively debated. Our data indicate that there is a relationship of remote effect to the neurological status. It is possible to show, by noninvasive, low-cost methods, remote CBF effects after stroke that may contribute to the assessment of brain functional impairment.

Acute Disease↗

PubMed1988

Recovery from aphasia and neglect after subcortical stroke: neuropsychological and cerebral perfusion study.

Cortical regional cerebral perfusion was assessed by N, N, N1-trimethyl-N1-(2)-hydroxy-3-methyl-5-(I-123) iodobenzyl-1, 3-propanediamine 2 HCl I-123 (HIPDM) and single photon emission computerised tomography (SPECT) in six aphasic and two neglect patients with unilateral subcortical vascular lesions. Assessments were carried out both in the acute phase and after a period ranging from 1 to 6 months after stroke onset. In all patients an almost complete spontaneous recovery occurred and was associated with a significant improvement of cortical perfusion. A relationship between severity of aphasia and degree of cortical hypoperfusion was found, in both the acute and the follow up assessments, in the aphasic subgroup.

Adult↗

PubMed1988

Technetium-99m HM-PAO-SPECT study of regional cerebral perfusion in early Alzheimer's disease.

Regional cerebral perfusion was evaluated by single photon emission computed tomography (SPECT) using technetium-99m hexamethylpropyleneamine oxime ([99mTc]HM-PAO) in sixteen patients with Alzheimer's disease (AD) in early clinical phase and in 16 healthy elderly controls. In all patients transmission computed tomography (TCT) and/or magnetic resonance imaging (MRI) did not show focal brain abnormalities. Relative to normal subjects, AD patients showed significant reductions in cortical/cerebellar activity ratio: cortical perfusion was globally depressed with the largest reductions in frontal and posterior temporo-parietal cortices. Asymmetries of relative perfusion between cerebral hemispheres were also demonstrated when language was affected or visuospatial functions were unevenly impaired. In patients with early AD, SPECT provides functional information to be compared with clinical and psychometric data.

Aged↗

PubMed1987

Cerebellar diaschisis in pontine ischemia. A case report with single-photon emission computerized tomography.

Regional cerebral and cerebellar blood flows were studied by N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-[123I]iodobenzyl)-1,3- propanediamine 2 HCl (I-123 HIPDM) and single-photon emission computerized tomography (SPECT) in a patient with an ischemic lesion of the pons. An asymmetry of perfusion of the cerebellar hemispheres, normal on transmission computerized tomography scan, was demonstrated by SPECT studies in the early acute phase and confirmed 15 days after. This finding may be related to the interruption of the corticopontocerebellar pathways.

Aged↗

PubMed1987

Cerebral hemispheric and contralateral cerebellar hypoperfusion during a transient ischemic attack.

We studied a 79-year-old woman within 3 h of the onset of a motor aphasia and a right hemiparesis. Single photon emission computed tomography (SPECT) showed a 24% decrease in the perfusion of the left middle cerebral artery territory and a 16% reduction in the perfusion of the right cerebellum. A mild naming difficulty was the neurological deficit at the end of the SPECT examination, and complete recovery was achieved within 24 h. Repeated SPECT study 10 days later was normal. This is the first report of focal hemispheric and contralateral cerebellar hypoperfusion in transient cerebral ischemia.

Aged↗

PubMed1987

Aphasia and neglect after subcortical stroke. A clinical/cerebral perfusion correlation study.

Sixteen patients with unilateral subcortical haemorrhagic or ischaemic stroke, confirmed by CT, were evaluated for the presence of aphasia and neglect. Compared with patients without neuropsychological deficits, left brain-damaged aphasic and right brain-damaged neglect patients showed a significantly greater reduction of cortical perfusion on N,N,N1-trimethyl-N1-(2)-hydroxy-3-methyl-5-(I-123) iodobenzyl-1,3-propanediamine 2 HCl I-123 (HIPDM) and single photon emission computerized tomography (SPECT). These results suggest that major cortical derangement is the crucial factor for the appearance of aphasia or neglect after a subcortical stroke. These remote effects, which are related to the size of the subcortical lesion, are interpreted in terms of interruption of neural connections (diaschisis).

Adult↗

PubMed1987

Cerebral arterial spasm after subarachnoid hemorrhage. A case report with SPECT and iodine-123 HIPDM.

Cerebral arterial spasm following subarachnoid hemorrhage can be responsible for secondary neurological deficits and can influence history, prognosis, and results of surgical treatment. The demonstration of vasospasm can be important for therapy. The use of I-123 HIPDM and SPECT in evaluating regional cerebral blood flow showed the effects on cerebral perfusion of diffuse arterial spasm in a case of subarachnoid hemorrhage and its recovery. There was a parallel with clinical neurological status.

Female↗

PubMed1987

Long-term noninvasive single photon emission computed tomography monitoring of perfusional changes after EC-IC bypass surgery.

The rCBF was evaluated using I-123 HIPDM and single photon emission computed tomography (SPECT) on 14 patients undergoing extracranial-intracranial (EC-IC) bypass surgery because of internal carotid artery (ICA) occlusion. Before surgery, all patients showed cortical areas of hypoperfusion over the affected cerebral hemisphere. Shortly after EC-IC bypass a rCBF increase was observed in six patients. However, at the 6 and 12 month follow-ups, with angiographic control of bypass patency, rCBF studies did not show any significant rCBF change. Long-term noninvasive tomographic monitoring of perfusion changes occurring after EC-IC bypass surgery failed to show a long-lasting improvement in perfusion.

Adult↗

PubMed1986

The anatomy of unilateral neglect after right-hemisphere stroke lesions. A clinical/CT-scan correlation study in man.

The anatomical correlates of extrapersonal visual neglect were investigated in 110 right-handed stroke patients with lesions confined to the right hemisphere. Neglect is much more frequently associated with retrorolandic damage, as compared with frontal lesions. The inferior parietal lobule appears to be the area most frequently involved in patients with cortical lesions showing signs of neglect. When the cerebral lesion is confined to deep structures, neglect occurs much more frequently when grey nuclei such as the thalamus and the basal ganglia are damaged; a remarkable number of negative cases were, however, found. Conversely, lesions limited to the subcortical white matter are rarely associated with neglect. The relevance of these results to anatomophysiological models of directed attention and neglect is discussed.

Adult↗

PubMed1986

Unilateral neglect: personal and extra-personal.

Ninety-seven right brain-damaged patients were given two tasks aimed at assessing unilateral neglect in personal and in extra-personal space. The frequency of the two aspects of neglect, as well as their patterns of association with each other and with more elementary neurological disorders are reported and discussed. The results suggest a non-unitary frame of spatial reference for unilateral neglect, which may tentatively be interpreted in terms of a personal vs extra-personal dichotomy.

Animals↗

PubMed1986

Unawareness of disease following lesions of the right hemisphere: anosognosia for hemiplegia and anosognosia for hemianopia.

Unawareness of motor and visual-field defects was investigated in 97 right brain-damaged subjects. Both kinds of anosognosia were found to be double-dissociated from more elementary neurological disorders and from personal and extra-personal neglect. The relationships between anosognosia and unilateral neglect are discussed and allusion is made to the implications concerning the neurological organization of higher control functions.

Adult↗

PubMed1986

Sequential assessment of regional cerebral blood flow, regional cerebral blood volume, and blood-brain barrier in focal cerebral ischemia: a case report.

Regional CBF (rCBF) and regional cerebral blood volume (rCBV) were evaluated by N,N,N'-trimethyl-N'-(2)-hydroxy-3-methyl-5-[123I]iodobenzyl-1, 3-propanediamine-2 HCl- and 99mTC-labeled red blood cells, respectively, and single-photon emission computerized tomography (SPECT) in a patient with focal cerebral ischemia. Sequential transmission computerized tomography (TCT) and SPECT functional data were compared with clinical findings to monitor the pathophysiological events occurring in stroke. A lack of correlation between rCBF-rCBV distributions and blood-brain barrier (BBB) breakdown was found in the acute phase. In the face of more prolonged alteration of BBB, as seen by TCT enhancement, a rapid evolution of transient phenomena such as luxury perfusion was shown by SPECT studies. Follow-up of the patient demonstrated a correlation between the neurological recovery and a parallel relative improvement of the cerebral perfusion.

Adult↗

PubMed1984

Spontaneous CSF rhinorrhea through the lamina cribrosa associated with primary empty sella.

Spontaneous CSF rhinorrhea associated with primary empty sella is a recently recognized condition. Because of its surgical indication, the preoperative evaluation of the possible site of the fistulous tract could be of fundamental importance. Most cases of primary empty sella reported in the literature have shown evidence of leakage through the sellar floor into the sphenoid sinus, thus requiring a transphenoidal approach. Non-traumatic defects in the anterior fossa are rarely reported in the literature. We have collected three new cases in which CT cisternography with non-ionic water-soluble contrast medium ruled out the possibility of a transellar fistula, thus suggesting a possible leak in the area of the lamina cribrosa. This was confirmed by the surgical outcome and by the follow-up of each patient.

Adult↗

PubMed1984

Rapid size reduction of giant prolactinoma following medical treatment.

A giant macroprolactinoma causing hydrocephalus was demonstrated by computed tomography in a 13-year-old boy complaining of headache and visual disturbances. Three weeks after beginning of medical treatment with dopaminergic drugs, an impressive reduction of tumor size and disappearance of hydrocephalus was noted. The patient is doing well at 5 months follow-up.

Adolescent↗