[Classification of parkinsonian syndromes via factorial discriminant analysis of brain SPECT data]. / Intérêt de l'analyse factorielle discriminante pour classer les syndromes parkinsoniens à partir de la tomoscintigraphie d'émission monophotonique.

INTRODUCTION: The objective was to assess the value of single photon emission computerized tomography (SPECT) and factorial discriminant analysis (FDA) in the differential diagnosis of Parkinson's disease (PD), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD). PATIENTS AND METHODS: Sixty-two patients with clinical diagnoses of either CBD, PSP or PD were studied using brain HmPaO-SPECT. Thirteen pairs of regions of interest (ROIs) were drawn on the slices located 50mm and 90mm above the canthomeatal plane. Twenty-six uptake indices and 13 asymmetry indices were determined. FDA was performed in order to determine whether or not the patients could be classified into the correct clinical group on the basis of SPECT data alone. The most discriminant parameters were used to generate two predictive scores, which were tested in a second group of 15 patients. RESULTS: FDA of all 39 variables correctly classified all the patients. A subset of 10 variables was used to build predictive scores, which correctly classified 90% of PD patients, 100% of PSP patients and 86% of CBD patients. When tested in the validation group of 15 patients, these predictive scores correctly classified 87% of the individuals. The frontal medial, temporoparietal and parietal regions were the most discriminant. CONCLUSION: Using SPECT data alone, this study enabled us to distinguish between PD, PSP and CBD in patients with clear clinical presentations of the diseases in question. This novel, statistical approach provides reliable information. However, a prospective study dealing with de novo parkinsonian syndromes will be necessary.

[Positron emission tomography: current use in internal medicine and future perspectives]. / La tomographie d'émission de positons en médecine interne: applications actuelles et perspectives d'avenir.

PURPOSE: Fluorodeoxyglucose positron emission tomography (FDG-PET) is a promising imaging technique that has already proven effective in modifying patient care in oncology. Fluorodeoxyglucose still remains the main radiopharmaceutical agent routinely used for PET imaging. A growing interest has recently lead to broaden PET research on benign disorders. The field of inflammatory or immune diseases and globally the field of internal medicine could also be impacted by FDG-PET. MAIN POINTS: Great vessels vasculitides and fever of unknown origin have both been studied by several teams and could become indications for PET. In addition, current indications now extend to paraneoplastic syndromes. It is thus possible to foresee that the clinical applications for PET will continue to expand in these patients. PERSPECTIVES AND PROJECTS: In the future, inflammatory arthritis, chronic inflammatory bowel diseases, systemic erythematous lupus, histiocytosis, or pulmonary and retroperitoneal fibrosis might benefit from PET even if, available data remains scarce to this day. Although PET will probably alter the landscape of patient management in internal medicine in the near future, additional clinical research is still needed to ascertain the exact role of PET.

[18FDG PET: a new criterion for disease activity in Takayasu arteritis]. / La TEP au 18FDG au cours de l'artérite de Takayasu: un marqueur d'activité de la maladie.

INTRODUCTION: Takayasu arteritis (TA) is an inflammatory arteritis affecting large vessels, predominantly the aorta, its main branches, and the pulmonary arteries. Up to now, arteriography was considered as the "gold standard". But others exams are emerging in the management of TA: vascular ultrasound, angio-scanner, magnetic resonance imaging and 18FDG positron emission tomography (18FDG PET). Such investigations allow a study of the lumen but also of the arterial walls. However, at the time, no biological or radiological test is able to determine the activity of TA. 18FDG PET could be effective to estimate the disease activity. EXEGESIS: We report the case of a young woman for who 18FDG PET permit to assert a relapse of TA. CONCLUSION: 18FDG PET could be effective to estimate the disease activity.

Comparison between Leukoscan (Sulesomab) and Gallium-67 for the diagnosis of osteomyelitis in the diabetic foot.

OBJECTIVES: The diagnosis of osteomyelitis in patients with diabetic foot is difficult both clinically and radiologically. An early diagnosis is crucial to optimize therapeutic strategy. Among the diagnostic methods currently used, scintigraphy with ex-vivo labelled white blood cells is the gold standard, but cannot be performed in all centers; therefore 67Gallium citrate (67Ga) imaging in combination with a bone scintigraphy is still widely used. METHOD: The results of imaging 24 diabetic patients with 31 suspected osteomyelitic lesions using the antigranulocyte Fab' fragment (Sulesomab or LeukoScan or immunoscintigraphy) were prospectively compared with results from the bone scan coupled with 67Ga. The diagnosis of osteomyelitis was confirmed by either biopsy or follow-up, radiological imaging and clinical outcome. RESULTS AND CONCLUSION: Sulesomab correctly identified 12 of 18 osteomyelitic lesions while 67Ga was able to detect only 8 of 18. Therefore the sensitivity is 67% for Sulesomab and 44% for 67Ga. Among the 13 non-osteomyelitic lesions imaging with Sulesomab was able to rule out infection in 11 cases and 67Ga in 10 cases. The specificity is therefore 85% for Sulesomab and 77% for 67Ga. Image interpretation for Sulesomab in this group of patients is occasionally suboptimal when imaging is performed at 3 hours post injection. High vascular background in the early images may obscure infection especially in small bones. Practically, scintigraphy with Sulesomab is fast and simple due to ease of labeling, no ex-vivo handling of blood, low radiation and provides rapid diagnosis. The diagnosis of osteomyelitis obtained by the antibody fragment scintigraphy influences the management (guided biopsy) and therapy. In several patients, imaging with Sulesomab was able to rule out osteomyelitis, helping to avoid useless antibiotic therapy and its associated side effects.

Regional cerebral blood flow imaging: a quantitative comparison of 99mTc-bicisate with 133Xe using single photon emission computed tomography.

The aim of this study was to compare 99mTc-bicisate with 133Xe inhalation in regional CBF (rCBF) imaging. Five healthy volunteers and five patients were imaged with both techniques. Regional standardized values (SVs) of 99mTc-bicisate, uptake indexes (UIs), and asymmetry indexes (AIs) were compared quantitatively with, respectively, rCBF, flow indexes (FIs), and AIs. Areas with highest rCBF (sylvian and thalamic areas) appeared to be underestimated with 99mTc-bicisate, but significant correlations were found between SV and rCBF (n = 140, r = 0.468, p < 0.01) and for the 10 subjects between UI and FI and between AIs (p < 0.0001). There are therefore distinct regional differences in the cerebral distinction of 99mTc-bicisate and CBF, particularly in the thalamus and the temporal cortex. It is probable but not yet proved that an underestimation of high flow rates occurs with bicisate.

Periventricular and white matter magnetic resonance imaging hyperintensities do not differ between Alzheimer's disease and normal aging.

We studied normotensive and nondiabetic subjects, free of cardiac disorders, to determine whether Alzheimer's disease is a possible factor of magnetic resonance imaging (MRI) white matter or periventricular hyperintensities, and to investigate relationships between computed tomographic scan and MRI changes. We failed to reveal (1) any difference in the severity of MRI white matter and periventricular hyperintensities between patients and controls, (2) any correlation of MRI white matter and periventricular hyperintensities with either ages or Mini-Mental State Examination scores. We found (1) a poor interobserver agreement, and (2) a correlation between computed tomographic scan and MRI white matter changes but not between computed tomographic and MRI periventricular changes. We conclude that MRI periventricular and white matter hyperintensities are frequent incidental findings in the elderly and do not significantly differ between patients with Alzheimer's disease and healthy controls.

Remote regional cerebral blood flow consequences of focused infarcts of the medulla, pons and cerebellum.

UNLABELLED: The aim of this study was to evaluate regional and remote diaschisis of inferior brain stem or cerebellar infarcts in 25 patients presenting with relatively limited lesions. Patients presented with medullary, pontine or cerebellar infarction. METHODS: Lesions were evaluated on MRI (0.5 T). Regional cerebral blood flow (rCBF) was assessed by means of SPECT, after injection of 9rmTc-hexamethyl propyleneamine oxime (HMPAO) and, when possible, inhalation of 133Xe in the same session. For each method, asymmetry indices (Als), comparing contralateral to ipsilateral rCBF values, were calculated in four areas of each cerebral hemisphere and in the cerebellum and later compared with values obtained in healthy subjects (P = 0.05). RESULTS: Higher rCBF values were observed in the contralateral cerebellum in 2 of 7 patients with selective lateral medullary lesions, and cerebellar Als were significantly increased. When a cerebellar infarct was associated with a lateral medullary lesion, the cerebellar and contralateral hemispheric asymmetries were more severe. Unilateral paramedian pontine infarcts had more frequent consequences on the cerebellum (2 of 3 cases), with rCBF or tracer uptake being reduced in the ipsilateral or the contralateral lobe. Inverse cerebral hemispheric asymmetry could then be observed. Bilateral pontine lesions were difficult to evaluate. Using 99mTc-HMPAO, discrete cerebellar asymmetry was observed in 3 of 6 cases. Pure cerebellar infarcts in the posterior inferior cerebellar artery territory were always associated with a severe ipsilateral flow drop in the cerebellum, and contralateral hemispheric diaschisis was frequent (3 of 4 patients), predominating in the frontotemporal cortex and subcortical structures. This was also more obvious using 99mTC-HMPAO than 133Xe. Variance analysis showed that hemispheric diaschisis was more severe in mixed brain stem and cerebellar infarcts than in pure cerebellar or brain stem lesions. Furthermore, cerebellar and hemispheric AI values were not correlated with measurements of clinical deficits, disability or handicap. CONCLUSION: Unilateral and limited inferior brain stem lesions can have ipsi- or contralateral consequences on the cerebellum and cerebral hemispheres rCBF. These remote effects are related to lesions of the main pathways joining these structures, resulting in deactivation and, in some cases, overactivation. Contrary to what has been suggested, consequences on cerebral hemispheres are more severe in mixed cerebellar and brain stem infarcts than in pure cerebellar lesions.

Technetium HMPAO SPECT study in dementia with Lewy bodies, Alzheimer's disease and idiopathic Parkinson's disease.

UNLABELLED: The aim of this study was to compare the regional cerebral blood flow measurements studied by SPECT in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) to determine the contribution of SPECT to the differential diagnosis of these two diseases. METHODS: SPECT analysis with 99mTc-hexamethyl propyleneamine oxime (HMPAO) was performed in 20 patients with probable DLB, 20 patients with probable AD and 20 patients with idiopathic Parkinson's disease (IPD). Ten pairs of regions of interest were analyzed. Tracer uptake was expressed as a corticocerebellar activity ratio. RESULTS: Compared with IPD, in the DLB group there was a global decrease of HMPAO uptake in cortical regions of interest except in the posterior frontal and occipital regions; in the AD group there was limited left temporal and parietal hypoperfusion. In the DLB group, frontal HMPAO uptake was significantly lower than in the AD group. Two predictive scores were established by a factorial discriminant analysis from six left cortical indices (medial frontal, lateral frontal, posterior frontal, temporoparietal, parietal and parietooccipital) and the Mini-Mental State Examination, which correctly classified 53 of 60 patients (88%) (DLB, 18 of 20; AD, 16 of 20; IPD, 19 of 20). CONCLUSION: These findings indicate the presence of diffuse cortical abnormalities in DLB and suggest that SPECT may be useful in discriminating in vivo DLB from AD, revealing mainly frontal hypoperfusion in the former group. We estimate that SPECT study increases the possibility of separating DLB and AD because both disorders share different patterns of cerebral blood flow abnormality.

Cognitive and psychiatric impairment in herpes simplex virus encephalitis suggest involvement of the amygdalo-frontal pathways.

The long-term neuropsychological and psychiatric sequelae of herpes simplex virus encephalitis (HSVE) and their relationship to the volume of temporal lesions and to amygdala and hippocampus damage remain undefined. We have conducted a prospective study of long-term sequelae in 11 patients with clinically presumed HSVE and detection of HSV DNA in the cerebrospinal fluid by polymerase chain reaction. Six months after encephalitis, patients underwent neuropsychological and language assessment. At the same stage, single photon emission computed tomography (SPECT) evaluated the occurrence of hypoperfusion with an index of asymmetry. MRI was used for the measurement of amygdala, hippocampus and cerebral lesions by two blind neurologists. The volume of the amygdala and hippocampus was compared with those of five controls, matched for age and level of education. Long-term memory disorders were seen in 6 patients, associated with the larger lesions and damage of at least two structures. Long-term behavioural changes with emotionalism, irritability, anxiety or depression were prominent in 7. Left prefrontal hypoperfusion appeared in 8 patients, associated with psychiatric disorders in 7 and left amygdala damage in 6. The reduction of amygdala and hippocampus volume was correlated with the overall volume of lesions. Different patterns of mesial temporal lobe damage occurred, involving either amygdala alone, or amygdala and hippocampus, but never hippocampus alone. MRI volumetric measurements in HSVE could be a good indicator of long-term prognosis. Persistant behavioural changes could be related to an amygdala and frontal dysfunction.

A semiquantative rating scale for the assessment of signal hyperintensities on magnetic resonance imaging.

Differences in grading signal hyperintensities on magnetic resonance imaging may explain earlier reported conflicting results in studies of normal aging and dementia. We designed a new rating scale in which periventricular and white matter signal hyperintensities as well as basal ganglia and infratentorial signal hyperintensities are rated separately in a semiquantative way. In this study we compared the inter- and intra-observer agreements of this scale to the widely used rating scale of Fazekas. We confirmed the poor to reasonable intra- and inter-observer agreements of the Fazekas scale. The new scale, although more elaborate, provided good agreements with respect to the white matter, basal ganglia and infratentorial signal hyperintensities. In rating periventricular hyperintensities this scale yielded no advantage. It is concluded that this scale may be of use in studies especially focussing on deep white matter pathology on MRI, because it provides more detailed information, with good intra- and inter-observer reliability.

[The delusion of place: contribution of the measurement of cerebral deficit]. / Le délire des lieux: apport de la débitmétrie cérébrale.

The authors report the observation of a 61-year-old female patient who, following a right frontal-temporal ischemia, presented disorientation with respect to her surroundings. She was convinced during her hospital stay that her house had been transformed into a hospital. There was no evidence of intellectual confusion or deterioration, and the neuropsychological examination revealed visuo-spatial disturbances only. A low basal cerebral blood flow was found in the right anterior hemisphere which further decreased when the patient was asked where he was. It is hypothesized that confabulatory responses corresponded to a disinhibition of the left hemisphere from the control of the hemisphere dominant in dealing with visuo-spatial data.

Early and delayed distribution of N-isopropyl-[123I]-p-iodoamphetamine in haemorrhagic and ischaemic brain.

Single photon emission computed tomography (SPECT) was used to study redistribution of N-isopropyl-[123I]-p-iodoamphetamine (IAMP) in 10 patients with intracerebral haemorrhage and 7 with ischaemic stroke. Delayed/early IAMP uptake ratios (D/E) were calculated for four different cerebral zones: haematoma or infarct, perilesional, normal and crossed cerebellar diaschisis areas. Delayed uptake was observed in all areas, but there were no significant differences between the haematoma and infarct results nor between the lesional and perilesional results. Delayed redistribution of IAMP therefore did not seem to be associated with neuronal metabolic activity.

Cerebral blood flow in major depression and dysthymia.

Using single photon emission computerized tomography (SPECT) with a 99mTc-HMPAO perfusion technique, we studied the regional cerebral blood flow (rCBF) of 42 drug-free inpatients suffering from Major Depression' (n = 21) or dysthymia with the super-imposed diagnosis of a major depressive episode (n = 21). The patients with Major Depression had a significantly lower frontal and posterior rCBF ratio than those with Double Depression. Left frontal region indices showed a slight overlap between the two groups. There was no correlation between the severity of the illness and the rCBF indices. Different qualitative cerebral dysfunctions may be implicated in these two affective disorder sub-types.

Anxiety, emotion and cerebral blood flow.

Regional cerebral blood flow was measured by the xenon inhalation technique using a DSPECT system, during neutral and emotional auditory stimulations. Subjects were 10 high and 10 low trait anxiety, right-handed females. State anxiety was retrospectively assessed. Results indicated a lower rCBF in the high trait or state anxiety subjects who presented also a global rCBF asymmetry in the right > left direction. Additionally, the emotional content of the stimuli interacted significantly with the side of the brain in the thalamic area.

Pure sensory stroke revealing a complex malformation of extra- and intracranial cerebral arteries.

Pure sensory strokes (PSS) are usually due to thalamic lacunar infarcts. We report a case of PSS in a 34-year-old female suffering from migraine who complained of sudden isolated left-sided paresthesia involving face, upper and lower limbs. We found a complex vascular abnormality associating internal carotid artery occlusion, posterior cerebral artery agenesia, aneurysm at the posterior face of the carotid siphon and angiomatous rete at the top of the basilar artery. The acquired origin of the carotid artery occlusion by possible neonatal dissection is probable since this patient has a permeable carotid canal on CT scan.

A study of the behaviour of cobalt chloride during the labelling of leukocytes with 99Tcm-HMPAO stabilised in vitro by the addition of cobalt chloride solution.

The method described by Weisner et al. for stabilizing 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) with cobalt chloride hexahydrate solution is the most promising developed to date. The aim of our work was to study the behaviour of cobalt during the labelling of leukocytes with 99Tcm-HMPAO stabilized in vitro using this method. Three parallel labellings were carried out using six blood samples taken from polycythaemic patients. The first set of labellings was performed using 99Tcm-HMPAO, the second set using 99Tcm-HMPAO stabilized with cobalt chloride hexahydrate solution "spiked' with 57Co-chloride, and the third set using 57Co-chloride solution alone. Measurements of radioactivity content were made on the leukocyte pellets after washing at five time points post-labelling (t = 0, 30 min, 1 h, 2 h and 4 h). The data show that leukocytes do not retain cobalt during labelling with stabilized 99Tcm-HMPAO. Studies carried out in parallel demonstrated that the presence of cobalt in the cell-labelling medium had no effect on cell viability.

[Computerized tomography of the distribution of N-isopropyl-p-123 iodoamphetamine in cerebrovascular pathology. Comparison with studies using the 133-xenon inhalation method]. / Mesure tomographique de la distribution de la N-isopropyl-p-123 iodo-amphétamine en pathologie vasculaire cérébrale. Comparison avec la mesure par inhalation de Xéno133.

123Iodo-Amphetamine (IAMP) brain distribution was studied with a specially dedicated multilevel tomographic system in 30 patients with vascular ischemic (18) or hemorrhagic (12) disorders. Results were compared with clinical data, CT scan and rCBF measurement obtained by the 133Xe continuous inhalation method. Abnormalities with IAMP were found in 27 cases, in good agreement with the results obtained by the Xenon inhalation technique in 21 studies from the 22 where that method was possible. For 80% cases there was also a good agreement between the results obtained by the IAMP and CT scan: one case normal, and 23 observations with abnormalities. This is true for the localization of lesions, but IAMP appears able to shown remote abnormalities, i.e. crossed cerebellar diaschisis or functional deactivation, in the absence of CT scan lesions in the corresponding areas. This is of particular interest in the protracted regressive ischemic neurologic disorders (PRIND): CT scan were normal in all five observations but IAMP showed abnormalities in four cases. IAMP is however very expensive, so it has to be used only when 133Xe inhalation is technically impossible.

Mismatch between iodine-123 and xenon-133 SPECT rCBF measurement.

This report is concerned with the case of a man afflicted by multiple cerebral arteriovenous malformations. The rCBF measurement with Xe-133 inhalation was relatively elevated. However, I-123 iodoamphetamine imaging showed a relative reduction in radioactivity, and was a more accurate reflection of the clinical situation.

[Regional cerebral blood flow and its reactivity to acetazolamide in transient ischemic attacks. Study of 20 cases by gamma emission tomography]. / Le débit sanguin cérebral local et sa réactivité à l'acétazolamide dans les accidents ischémiques transitoires. Etude de 20 cas par tomographie d'émission gamma.

We have studied regional cerebral blood flow (= test) and reactivity of acetazolamide injection (= retest) in 20 patients who had presented transient ischemic attacks (TIA). The cerebral blood flow was measured by the atraumatic Xenon 133 inhalation method and single photon emission tomography using a specially dedicated tomograph (TOMOMATIC 64), allowing 3 tomographic levels (OM + 1, + 5, + 9 cm). Measurements were realized in a quiet, dark room. Acetazolamide (500 mg or 1000 mg) was injected intravenously immediately after the test, and the retest was performed 15 minutes after, in the same conditions. Results obtained from paired ROIS were analysed in terms of asymmetric index for the test, of relative reactivity for retest in regard of normal values established in a group of healthy volunteers. All patients had neurological examination, vascular explorations and CT scan. Six of the patients showed a bad reactivity (abolished or strongly decreased) which was evoked a significant hemodynamically stenosis, reflecting the loss of collateral capacity. In the other group results were diversified, and we classified these in 4 groups: "normal" (7), "luxury perfusion" (3), "limited infarction" (1), and "incomplete infarction" (3). When these groups were plotted versus duration of onset and delay between the last attack and the moment of the measurement, "incomplete infarction" clearly appears as a step between brief TIA (less of 1 hour) and "limited infarction". So rCBF and reactivity to acetazolamide are of major interest for the physiopathological classification of TIAs, but also for treatment and prognosis.

[Activation of deficient right cerebral blood flow by language after global aphasia]. / Activation du débit sanguin cérébral droit par le langage après une aphasie globale.

A 39-year old patient abruptly presented with global aphasia. Six years later a mild deficit of articulation and sentence comprehension persisted. A cerebral blood flow study showed that a) during verbal activations, the blood flow increased in the right hemisphere and decreased around the lesion in the left hemisphere; b) the activation was globally higher than in the control group. These data suggest that the right hemisphere plays a significant role in the recovery from aphasia in patients with severe left hemispheric lesions.