Regional cerebral perfusion was evaluated by SPECT with technetium 99m hexamethylpropyleneamine oxime (99mTc HMPAO) as a tracer in 21 patients presenting with Parkinson's disease and in 11 normal controls. In the parkinsonian patients, scans were performed both off treatment, and after levodopa, and clinical dopaminergic responsiveness was evaluated. Uptake of HMPAO by the basal ganglia was significantly decreased in the parkinsonian subjects, compared with normal controls. This reduction was seen in both responders (n = 14) and non-responders (n = 7) to dopaminergic treatment. Uptake of HMPAO by the basal ganglia rose after treatment with levodopa, but the change was similar in both responders and non-responders. By contrast a striking difference in cortical HMPAO uptake was found between responders and non-responders, with significantly lower uptake in the medial temporal and posterior parietal cortex in the non-responders. This reduction was symmetrical. Basal ganglia perfusion assessed by this technique is unlikely to be of use in the diagnosis of Parkinson's disease that is responsive to dopaminergic treatment. The presence of extensive cortical involvement on a baseline scan correlates with a lack of dopaminergic responsiveness, however, and this may be useful diagnostically.
99mTc complex of hexamethylpropylene amine oxime (99mTc-HMPAO), which has been used as a tracer for regional cerebral blood flow (rCBF), has been shown to localize in primary brain tumors with wide spectrum of its uptake. The causes of the wide spectrum of tumor uptake, however, has not been understood in detail. We performed autoradiographic study with this agent to get further knowledge about HMPAO distribution in 10 cases of transplanted rat gliomas. Eight cases of rat gliomas without tumor necrosis, showed decreased uptake of 99mTc-HMPAO in the autoradiography (average tumor/normal (T/N) uptake ratio: 0.75, range: 0.40-0.90). On the other hand, two cases with tumor necrosis revealed increased uptakes of this agent in central necrotic area. T/N uptake ratios of these two cases were 1.23 and 1.42, respectively. In addition, three patients with histologically proven glioblastoma with tumor necrosis were studied after administration of 20mCi 99mTc-HMPAO. Two out of three patients showed higher uptake of 99mTc-HMPAO in tumor necrotic area than the contralateral area. Our findings suggest that the necrotic area of brain tumor may retain 99mTc-HMPAO and causes an increased uptake.
Background and purpose
Patients with internal carotid artery (ICA) occlusion can demonstrate impaired cerebral vascular reserve (CVR). The detection of CVR using single photon emission CT (SPECT) is nowadays widely accepted as a predictor in the diagnostic pathway in patients considered for cerebral revascularization. Recently perfusion CT (PCT) gained widely acceptance in stroke imaging The present study was aimed at comparing the results of perfusion CT (PCT) and 99mTc-HMPAO SPECT with acetazolamide challenge in patients with ICA occlusion.
13 patients were included in the prospective evaluation. Both PCT and 99mTc-HMPAO SPECT were performed before and after the administration of acetazolamide. In detail, regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), adapted time to peak (Tmax) and mean transit times (MTT) were compared with SPECT data.
99mTc-HMPAO SPECT demonstrated an impairment of CVR in six patients. A preserved CVR was present in seven patients. All patients with impaired CVR proven by SPECT had a delayed MTT (mean +2.98 s) and a delayed Tmax (mean + 5.9 s), (both p < 0.005 compared with the non occluded side). 66% of patients with impaired CVR in SPECT showed a complete correlation of Tmax measurements in PCT with a high positive predictive value (PPV: 88.8%).
The prospective study demonstrated a highly significant correlation of perfusion parameters as' detected by 99mTc-HMPAO SPECT and the Tmax as detected by PCT in patients with ICA occlusion. Therefore this easy-to-perform technique seems to be an adequate method for the evaluation of cerebral perfusion in patients with ICA occlusion.
cerebral vascular reserve; perfusion CT; SPECT; internal carotid artery occlusion
Blood flow interruption in a cerebral artery causes brain ischemia and induces dramatic changes of perfusion and metabolism in the corresponding territory. We performed in parallel positron emission tomography (PET) with [15O]H2O, single photon emission computed tomography (SPECT) with [99mTc]hexamethylpropylene-amino-oxime ([99mTc]HMPAO) and ultrasonic ultrafast shear wave imaging (SWI) during, immediately after, and 1, 2, 4, and 7 days after middle cerebral artery occlusion (MCAO) in rats. Positron emission tomography and SPECT showed initial hypoperfusion followed by recovery at immediate reperfusion, hypoperfusion at day 1, and hyperperfusion at days 4 to 7. Hyperperfusion interested the whole brain, including nonischemic areas. Immunohistochemical analysis indicated active angiogenesis at days 2 to 7, strongly suggestive that hyperperfusion was supported by an increase in microvessel density in both brain hemispheres after ischemia. The SWI detected elastic changes of cerebral tissue in the ischemic area as early as day 1 after MCAO appearing as a softening of cerebral tissue whose local internal elasticity decreased continuously from day 1 to 7. Taken together, these results suggest that hyperperfusion after cerebral ischemia is due to formation of neovessels, and indicate that brain softening is an early and continuous process. The SWI is a promising novel imaging method for monitoring the evolution of cerebral ischemia over time in animals.
middle cerebral artery occlusion; PET; shear wave imaging; SPECT; stroke; ultrasound
We combined behavioral testing with brain imaging using 99mTc-HMPAO (Amersham Health), to identify CNS structures reflecting alterations in pain perception in the streptozotocin (STZ) model of Type 1 diabetes. We induced diabetic hyperglycemia (blood glucose >300 mg/dl) by injecting male Sprague-Dawley rats with STZ (45 mg/kg i.p.). Four weeks after STZ, diabetic rats exhibited behaviors indicative of neuropathic pain (hypersensitivity thermal stimuli) and this hypersensitivity persisted for up to six weeks. Imaging data in STZ-diabetic rats revealed significant increases in the activation of brain regions involved in pain processing after six weeks duration of diabetes. These regions included secondary somatosensory cortex, ventrobasal thalamic nuclei and the basolateral amygdala. In contrast, the activation in habenular nuclei and the midbrain periaqueductal gray were markedly decreased in STZ rats. These data suggest that pain in diabetic neuropathy may be due in part to hyperactivity in somatosensory structures coupled with a concurrent deactivation of structures mediating antinociception.
The ideal imaging method in inflammatory bowel disease would reliably detect inflammation, identify the correct intestinal location, and assess the severity of the disease. The aim of this study was to compare scintigraphic methods of quantifying overall disease activity using both indium-111 (111In) and technetium-99M (99mTc) HMPAO labelled leucocyte scans. The four day faecal excretion of 111In was measured after 111In scintigraphy in 24 patients known to have inflammatory bowel disease. The same patients also underwent 99mTc HMPAO scanning. The scans were performed 10 days or less apart with no changes in treatment between scans. Bowel activity on the 99mTc HMPAO scans was assessed using a computer based method (scan score) and a visual grading method in a further 54 99mTc HMPAO. The results showed a close correlation between inflammatory activity defined by faecal 111In excretion and the scan score generated from the computer analysis of the 99mTc HMPAO image (Spearman rank correlation: rs = 0.78; p < 0.001). Accurate information to localise inflammatory activity could be obtained by simple visual assessment of both types of scan images, although image quality was superior with 99mTc HMPAO. Qualification of disease activity from 99mTc HMPAO images by visual grading was associated with a large variability, only 69% of scans had similar scores when graded by three observers. Computer generated image analysis was more reproducible. In conclusion, in inflammatory bowel disease 99mTc HMPAO scintigraphy and faecal 111In excretion correlated well. Either method can quantify and localise the inflammation. As 99mTc HMPAO scanning provides a quicker result, with a lower radiation dose, and avoids faecal collection, it may be the preferred method.
Functional activation protocols are widely applied for the study of brain-cognition relations. Only few take advantage of the intrinsic characteristics of SPECT, particularly those allowing cognitive assessment outside of the camera, in settings close to the standard clinical or laboratory ones. The purpose of the study was to assess the feasibility of a split-dose activation protocol with 99mTc-HMPAO using low irradiation dose.
Materials and methods
A two-scans protocol was applied to 12 healthy young volunteers using 270 MBq of 99mTc-HMPAO per scan, with each image associated to a particular experimental condition of the verbal n-back working memory task (0-back, 2-back). Subtraction method was used to identify regional brain activity related to the task.
Voxel-wise statistical analysis showed left lateralized activity associated with the 2-back task, compared to the 0-back task. Activated regions, mainly prefrontal and parietal, were similar to those observed in previous fMRI and 15O-PET studies.
The results support the use of 99mTc-HMPAO SPECT for the investigation of brain-cognition relations and demonstrate the feasibility of optimal quality images despite low radiopharmaceutical doses. The findings also acknowledge the use of HMPAO as a radioligand to capture neuro-energetic modulations linked to cognitive activity. They encourage extending the application of the described activation protocol to clinical populations.
99mTc-HMPAO SPECT; Brain imaging; Activation study; Working memory; Protocol validation
The study serves to optimise conditions for multi-pinhole SPECT small animal imaging of 123I- and 99mTc-labelled radiopharmaceuticals with different distributions in murine heart and brain and to investigate detection and dose range thresholds for verification of differences in tracer uptake.
A Triad 88/Trionix system with three 6-pinhole collimators was used for investigation of dose requirements for imaging of the dopamine D2 receptor ligand [123I]IBZM and the cerebral perfusion tracer [99mTc]HMPAO (1.2–0.4 MBq/g body weight) in healthy mice. The fatty acid [123I]IPPA (0.94 ± 0.05 MBq/g body weight) and the perfusion tracer [99mTc]sestamibi (3.8 ± 0.45 MBq/g body weight) were applied to cardiomyopathic mice overexpressing the prostaglandin EP3 receptor.
In vivo imaging and in vitro data revealed 45 kBq total cerebral uptake and 201 kBq cardiac uptake as thresholds for visualisation of striatal [123I]IBZM and of cardiac [99mTc]sestamibi using 100 and 150 s acquisition time, respectively. Alterations of maximal cerebral uptake of [123I]IBZM by >20% (116 kBq) were verified with the prerequisite of 50% striatal of total uptake. The labelling with [99mTc]sestamibi revealed a 30% lower uptake in cardiomyopathic hearts compared to wild types. [123I]IPPA uptake could be visualised at activity doses of 0.8 MBq/g body weight.
Multi-pinhole SPECT enables detection of alterations of the cerebral uptake of 123I- and 99mTc-labelled tracers in an appropriate dose range in murine models targeting physiological processes in brain and heart. The thresholds of detection for differences in the tracer uptake determined under the conditions of our experiments well reflect distinctions in molar activity and uptake characteristics of the tracers.
Electronic supplementary material
The online version of this article (doi:10.1007/s00259-009-1142-9) contains supplementary material, which is available to authorized users.
Brain; Heart; [123I]IBZM; Mice; Multi-pinhole SPECT; [99mTc]sestamibi
Arterial spin labelling (ASL) is increasingly available for noninvasive cerebral blood flow (CBF) measurement in stroke research. Here, a pseudo-continuous ASL technique (pCASL) was evaluated against 99mTc-D, L-hexamethylpropyleneamine oxime (99mTc-HMPAO) autoradiography in a rat stroke model. The 99mTc-HMPAO was injected (intravenously, 225 MBq) during pCASL acquisition. The pCASL and 99mTc-HMPAO autoradiography CBF measures, relative to the contralateral hemisphere, were in good agreement across the spectrum of flow values in normal and ischemic tissues. The pCASL-derived quantitative regional CBF values (contralateral: 157 to 177 mL/100 g per minute; ipsilateral: 9 to 104 mL/100 g per minute) were consistent with the literature values. The data show the potential utility of pCASL for CBF assessment in a rat stroke model.
ASL; CBF; stroke
with Alzheimer's disease (AD) showing a selective impairment of
episodic and semantic memory have recently been classified as affected
by focal temporal lobe dysfunction (FTLD) and considered as a distinct
subgroup of patients affected by a particular form of AD. The aim was
to compare the cerebral perfusion of patients with AD with FTLD and
patients with AD with the more typical profile of diffuse cognitive
patients with AD with FTLD, 14 patients with AD with dAD, and 12 normal
controls were studied. All the 24 patients with AD underwent a complete
neuropsychological assessment. SPECT examination with
[99mTc]-HMPAO, using a four head brain dedicated
tomograph, was performed in patients and controls. Tracer uptake was
quantified in 27 regions of interest (ROIs), including lateral and
mesial temporal areas. Mean counts in the 27 ROIs of controls, patients
with FTLD and those with dAD were compared using an ANOVA for repeated
measures with Bonferroni's correction. A logistic regression analysis, followed by a receiver operating characteristic (ROC) analysis, was
also applied to select SPECT patterns which significantly differentiated patients with FTLD and those with dAD.
scintigraphic patterns of abnormalities, shaping a double dissociation
between the FTLD and dAD groups, emerged: a bilateral mesial temporal
hypoperfusion, characteristic of FTLD and a posterior parietal (and
temporal parietal) hypoperfusion characteristic of patients with dAD.
scintigraphic findings provide further support to the hypothesis that
FTLD is not a mere stage but a distinct anatomoclinical form of AD. The
combination of neuropsychological tests and [99mTc]-HMPAO
SPECT may be very useful in identifying patients with FTLD from the
wider group of patients with dAD. This issue is particularly
worthwhile, as there is increasing evidence that patients with FTLD
have a slower rate of cognitive decline.
Loss of the α4β2 nicotinic receptor subtype is found at autopsy in Alzheimer's disease.
To investigate in vivo changes in this receptor using single‐photon‐emission CT (SPECT) with 123I‐5‐iodo‐3‐[2(S)‐2‐azetidinylmethoxy] pyridine (5IA‐85380), a novel nicotinic acetylcholine receptor ligand which binds predominantly to the α4β2 receptor.
32 non‐smoking subjects (16 with Alzheimer's disease and 16 normal elderly controls) underwent 123I‐5IA‐85380 and perfusion (99mTc‐hexamethylenepropyleneamine oxime (HMPAO)) SPECT scanning. Region of interest analysis was performed with cerebellar normalisation.
Significant bilateral reductions in nicotinic receptor binding were identified in frontal (left, p = 0.004; right, p = 0.002), striatal (left, p = 0.004; right, p = 0.003), right medial temporal (p = 0.04) and pons (p<0.001) in patients with AD compared to controls. There were no significant correlations with clinical or cognitive measures. The pattern of nicotinic binding significantly differed from that of perfusion in both patients with AD and controls. Both 123I‐5IA‐85380 and 99mTc‐HMPAO SPECT imaging demonstrated similar diagnostic performance in correctly classifying controls and patients with AD.
Using 123I‐5IA‐85380 SPECT we found changes consistent with significant reductions in the nicotinic α4β2 receptor in cortical and striatal brain regions. This method could facilitate diagnosis and may be useful for monitoring progression of the disease and response to treatment in patients with AD and related diseases.
Tc-99m ethyl cysteinate diethylester (ECD) and Tc-99m hexamethyl propylene amine oxime (HMPAO) are commonly used for single-photon emission computed tomography (SPECT) studies of a variety of neurologic disorders. Although these tracers have been very helpful in diagnosing and guiding treatment of neurologic disease, data describing the distribution and laterality of these tracers in normal resting brain are limited. Advances in quantitative functional imaging have demonstrated the value of using resting studies from control populations as a baseline to account for physiologic fluctuations in cerebral perfusion. Here, we report results from 30 resting Tc-99m ECD SPECT scans and 14 resting Tc-99m HMPAO scans of normal volunteers with no history of neurologic disease. Scans were analyzed with regions of interest and with statistical parametric mapping, with comparisons performed laterally (left vs. right), as well as for age, gender, and handedness. The results show regions of significant asymmetry in the normal controls affecting widespread areas in the cerebral hemispheres, but most marked in superior parietotemporal region and frontal lobes. The results have important implications for the use of normal control SPECT images in the evaluation of patients with neurologic disease.
brain asymmetry; brain imaging; SPECT
Tc-HMPAO isotope brain scans were performed in three patients who received hyperbaric oxygen treatment following carbon monoxide poisoning. Cerebral perfusion imaging provides an index of severity of the initial cerebral damage which correlated with outcome.
Objective: To compare the HMPAO SPECT cerebral perfusion patterns in early and late onset Alzheimer's disease.
Methods: Twenty patients with early onset disease (<65 years) and 44 patients with late onset disease (>65 years) were studied. All patients fulfilled NINCDS-ADRDA clinical criteria and had details of disease severity and length of history at the time of imaging. Technetium-99m HMPAO SPECT brain scans were acquired on a multi-detector gammacamera and analysed visually and with statistical parametric mapping (SPM99).
Results: Patients with early onset disease had significantly greater posterior cortical association area involvement whereas those with late onset disease had significantly greater medial temporal hypoperfusion. These findings were unchanged after controlling for disease severity and length of illness.
Discussion: These functional imaging findings of the differences between early and late onset Alzheimer's disease are supported by published findings that include histopathological and clinical evidence; namely late onset patients tend to present with the characteristic involvement of the medial temporal lobes producing marked memory loss whereas early onset patients present with predominant posterior cortical association area involvement. These age related findings should be borne in mind when clinically diagnosing, and interpreting functional brain imaging studies in, patients with suspected Alzheimer's disease.
Cranial CT and high resolution measurements of regional cerebral blood flow (rCBF) with brain dedicated single photon emission computer tomography (SPECT) and [99mTc]-d,l-hexamethylpropyleneamine oxime ([99mTc]-d,l-HMPAO) were performed before and after shunt operation in 14 consecutive patients with dementia and normal pressure hydrocephalus (NPH). When compared with a control group of 14 age matched healthy volunteers, the group of NPH patients was characterised by an enlarged subcortical low-flow region, significantly reduced rCBF and enhanced side-to-side asymmetry of rCBF in the central white matter, and enhanced side-to-side asymmetry in the inferior and mid-temporal cortex. Global CBF was normal. Shunt operation reduced the mean area of the ventricles on CT and of the subcortical low-flow region on SPECT. Global CBF was unchanged. All 14 patients had an abnormal pre-shunt rCBF pattern with enlargement of the subcortical low flow region, focal cortical blood flow deficits, or both. Shunt operation improved the clinical status in 11 patients, and the area of the subcortical low flow region correctly classified 3/3 unimproved and 10/11 improved patients. Shunt operation normalised or reduced the area of the subcortical low flow region in nine of 10 patients. It is concluded that SPECT with [99mTc]-d,l-HMPAO is a useful supplement in the diagnosis of NPH versus normal ageing, and that SPECT may help to identify patients not likely to benefit clinically from surgery.
The objective was to compare two neurophysiological variables in active amateur boxers with non-boxing sportsmen. 41 boxers and 27 controls were given psychometric tests: 34 boxers and 34 controls underwent technetium-99m hexamethylpropyleneamineoxime single photon emission computerised tomography (Tc-99m HMPAO SPECT) cerebral perfusion scans. The controls performed better at most aspects of the psychometric tests. Boxers who had fought fewer bouts had a tendency to perform better at psychometric tests than those boxers who had fought more bouts. Tc-99m HMPAO SPECT cerebral perfusion scanning showed that controls had less aberrations in cerebral perfusion than the boxers. In conclusion, significant differences were shown in two neurophysiological variables between young amateur sportsmen who box and those who do not. The long term effects of these findings remain unknown.
OBJECTIVES—To provide the clinician with a guide
to the clinical utility of 99mTc-HMPAO single photon
emission computed tomography (SPECT) and to the interpretation of
specific test results in the differential diagnosis of dementia.
METHODS—Three hundred and sixty three patients
with dementia were studied prospectively for a median three (range
1-6) years and classified into disease groups on the basis of
established clinical criteria. The degree to which different patterns
of cerebral blood flow (CBF) abnormality found on
99mTc-HMPAO SPECT imaging at the time of initial patient
presentation modified clinical diagnoses was determined by calculating
the likelihood ratios for pairwise disease group comparisons. The optimal clinical usage of 99mTc-HMPAO SPECT was determined
by calculating the percentage of significant test results for each
pairwise disease group comparison.
RESULTS—Bilateral posterior CBF abnormality was
found to significantly increase the odds of a patient having
Alzheimer's disease as opposed to vascular dementia or frontotemporal
dementia. Bilateral anterior CBF abnormality significantly increased
the odds of a patient having frontotemporal dementia as opposed to
Alzheimer's disease, vascular dementia, or Lewy body disease.
"Patchy" CBF changes significantly increased the odds of a patient
having vascular dementia as opposed to Alzheimer's disease. Unilateral
anterior, unilateral anterior plus unilateral posterior, and
generalised CBF abnormality failed to contribute to the differentiation
of any of these forms of dementia.
CONCLUSIONS—99mTc-HMPAO SPECT was
found to be most useful in distinguishing Alzheimer's disease from
vascular dementia and fronto temporal dementia, and least useful in
differentiating between Alzheimer's disease and Lewy body disease, and
between vascular dementia, frontotemporal dementia, and progressive
aphasia. It is suggested that CBF SPECT should be used selectively and
as an adjunct to clinical evaluation and CT.
recanalisation by thrombolysis is a conclusive therapy for acute
ischaemic stroke. But this therapy may increase the risk of
intracerebral haemorrhage or severe brain oedema. The purpose was to
evaluate usefulness of quantitative measurement of cerebral blood flow
by single photon emission computed tomography (SPECT) in predicting the
risk of haemorrhage or oedema, and determining the therapeutic options
in acute hemispheric ischaemic stroke.
was studied retrospectively between initial regional cerebral blood
flow (rCBF) quantitatively measured by technetium-99m-labelled hexamethylpropyleneamine oxime (99mTc-HMPAO) SPECT and
final clinical and radiological outcome in 20 patients who presented
hemispheric ischaemic stroke and were treated conservatively or
received early recanalisation by local intra-arterial thrombolysis. The
non-invasive Patlak plot method was used for quantitative measurement
of rCBF by SPECT.
residual rCBF was preserved over 35 ml/100 g/min had a low possibility
of infarction without recanalisation and regions where residual rCBF
was preserved over 25 ml/100 g/min could be recovered by early
recanalisation. However, regions where residual rCBF was severely
decreased (< 20 ml/100 g/min) had a risk of intracerebral haemorrhage
and severe oedema.
quantitative assessment of residual rCBF by 99mTc-HMPAO
SPECT is useful in predicting the risk of haemorrhage or severe oedema in acute ischaemic stroke. Therapeutic options should be determined based on the results of rCBF measurement.
Fifty patients with suspected intra-abdominal abscess were investigated prospectively with ultrasound and with 99mTc-hexamethylpropylene-amine oxime (HMPAO) isotope labelled mixed leucocytes, using 111-In tropolonate granulocyte scanning as the reference standard. Twenty five patients had inflammatory bowel disease (three were postoperative): 21 of these had Crohn's disease and four had ulcerative colitis. The remainder comprised nine with postoperative fever and 16 with fever and abdominal pain. An abscess was diagnosed when focal activity on serial 111-In tropolonate and 99m-Tc-HMPOA images at one, three, and 24 hours resulted in activity at least equal to liver activity at 24 hours. Thirteen abscesses were diagnosed using each type of white cell scanning, resulting in 100% sensitivity for 99m-Tc-HMPAO compared with 111-In tropolonate. Bowel inflammation was easily distinguished from abscess on serial images. Eight of these 13 abscesses were detected by ultrasound. Altogether 17 abscesses were found. Ultrasound detected 12, including four liver abscesses which were not purulent and had not been detected by white cell scanning. Ultrasound had a sensitivity of 71% (12 of 17) and a specificity of 87% (33 of 38) using all confirmed abscesses as the reference standard. White cell scanning showed a sensitivity of 76% (13 of 17: as a result of the four non-purulent liver abscesses) and a specificity of 100%. 99m-Tc-HMPAO scanning is as accurate as 111-In tropolonate scanning, and has several advantages including simplicity, availability, superior image quality, and reduced radiation dose. Both methods are more sensitive and specific than ultrasound for intra-abdominal abscess detection but ultrasound is advisable if a neutrophil infiltrate is not suspected.
OBJECTIVES—In mild Alzheimer's
disease, SPECT imaging of regional cerebral blood flow has highlighted
deficits in the posterior association cortex, and later in the disease
process, the deficit spreads to involve the frontal cortex. The ε4
allele of apolipoprotein E is a risk factor for Alzheimer's disease.
The effect of apolipoprotein E polymorphism on cerebral perfusion was
studied. The hypothesis was that those patients with Alzheimer's
disease who carry the ε4 allele would have more severe cerebral hypoperfusion.
METHODS—Thirty one patients with Alzheimer's
disease and eight age and sex matched control subjects were examined in
a three year longitudinal study. Patients with Alzheimer's disease
were divided into subgroups according to their number of ε4 alleles.
Regional cerebral blood flow ratios referred to the cerebellum were
examined by 99mTc-HMPAO SPECT. Apolipoprotein E genotypes
were determined by digestion of polymerase chain reaction products with
the restriction enzyme Hha1.
RESULTS—All patients with Alzheimer's disease had
bilateral temporoparietal hypoperfusion compared with control subjects.
The two ε4 allele subgroups had the lowest ratios at the baseline
assessment in the parietal and occipital cortices, and at the follow up
in the temporal, parietal, and occipital cortices. They had the highest reduction in percentage terms in the temporal and occipital cortices compared with the other subgroups. However, the global clinical severity did not differ at the baseline or follow up examinations between the subgroups.
CONCLUSION—Apolipoprotein E polymorphism is
involved in the pathogenesis and heterogeneity of Alzheimer's disease
as the most severe cerebral hypoperfusion was found in the ε4 allele
subgroups. This might have implications for therapeutic approaches in
To assess the regional cerebral blood flow (rCBF) in ischemic stroke, we analyzed the findings of single photon emission computed tomography (SPECT) using technetium-99m hexamethyl propyleneamine oxime (Tc-99m HMPAO). The SPECT images revealed abnormal areas of decreased perfusion in 29 out of 31 subjects (93.5%), which represented a higher detection rate than those for CT and MR (89.5%, respectively). Also, the areas of decreased perfusion were frequently larger than the lesions on CT and MR. Areas of decreased perfusion remote from the CT/MR lesions were found in 10 patients, including 8 with crossed cerebellar diaschisis (CCD). Thus, studies of rCBF by Tc-99m HMPAO SPECT can be useful in the assessment of ischemic stroke.
investigate the use of 99mTc-HMPAO (hexamethyl propylene
amine oxime) leucocyte scintigraphy as a non-invasive screening test for inflammatory bowel disease.
with suspected Crohn's disease, in whom routine investigation using
barium contrast radiology, upper gastrointestinal endoscopy,
colonoscopy, and mucosal biopsies had identified severe gastroduodenal
and/or jejunal involvement.
leucocyte scintigraphic studies performed in each of these cases were
assessed by a radiologist who was blinded to the disease distribution.
RESULTS—In nine cases
there was no scintigraphic evidence of inflammation in the proximal
gastrointestinal tract. The 10th child had both gastroduodenal and
jejunal involvement, but scintigraphy only revealed faint jejunal positivity.
leucocyte scintigraphy should not be depended upon as a screening test
for Crohn's disease. False negative results are likely in cases with
Crohn's disease confined to the proximal gastrointestinal tract.
To relate cerebral perfusion abnormalities to subsequent changes in clinical status among patients with mild cognitive impairment (MCI).
Perfusion single photon emission computed tomography (SPECT) images were acquired in 105 elderly patients without dementia with MCI, using 99mTc‐HMPAO. Clinical outcome after a 5‐year follow‐up period was heterogeneous.
Baseline SPECT data differed in those patients with MCI who were later diagnosed with Alzheimer's disease (the converter group) from those patients with MCI who experienced clinically evident decline but did not progress to a diagnosis of Alzheimer's disease within the follow‐up period (the decliner group), from patients with MCI who had no clinical evidence of progression (the stable group), and from a group of 19 normal subjects (the control group). The most consistent decreases in relative perfusion in converters compared with the normal, stable and decliner groups were observed in the caudal anterior cingulate, and in the posterior cingulate. In addition, converters showed increased relative perfusion in the rostral anterior cingulate in comparison to the stable and decliner groups. A group of patients with Alzheimer's disease were also included for purposes of comparison. The group of patients with Alzheimer's disease at baseline differed from each of the other groups, with temporoparietal regions showing the most significant reductions in perfusion.
These results suggest that clinical heterogeneity in MCI is reflected in SPECT perfusion differences, and that the pattern of perfusion abnormalities evolves with increasing clinical severity.
OBJECTIVES--To study the ability of technetium-99m hexamethyl propylene amineoxime (HMPAO) labelled lymphocyte scintigraphy to quantify synovial inflammation, and to analyse the kinetics of lymphocyte retention in the joints of patients with rheumatoid arthritis (RA). METHODS--After isolation of the lymphocytes, the cells were radiolabelled in vitro with 250 MBq 99mTc-HMPAO. The scans were performed 30 minutes, three hours and 20 hours after injection. RESULTS--An increase of the scintigram signal obtained at 20 hours was associated with a high joint swelling and joint pain score (F test = 3.07, p < 0.002), but not with the radiological score. A positive joint scintigram was predictive of active synovitis. Although the scintigram variation over time did not reach statistical significance, the kinetics of the scintigram signal tended to differ according to the disease duration: in early RA, active arthritis could be clearly imaged as early as 30 minutes, increased at three hours and the signal intensity persisted at 20 hours. In contrast, in long standing disease, the affected joints were imaged at 30 minutes, persisted unchanged at three hours, and the scintigram score decreased significantly at 20 hours. CONCLUSIONS--The study shows that 99mTc-HMPAO joint scintigraphy may be used to detect and to localise active rheumatoid arthritis.
The purpose of this study was to evaluate the effects of
various covariants on the distribution pattern of Tc-99m HMPAO in patients with Alzheimer's disease by correlation analysis. Twenty patients with Alzheimer's disease and 15 age matched normal subjects participated. Tc-99m HMPAO brain SPECT and x
ray computed tomography (CT) were acquired for each subject. SPECT
images were transformed to a standard size and shape by automated image
registration (AIR) and were used for group comparison by means of
SPM96. Voxel based covariance analysis was performed on standardised
images taking the age of patients, severity of disease (clinical
dementia rating scale, mini mental state examination, physical self
maintenance scale), and atrophy indices as variables. There was
significantly decreased regional cerebral blood flow (rCBF) in the
frontal, parietal, and temporal regions in the patient group
(p<0.001), more marked in those patients having severe dementia.
Covariance analysis disclosed that aging and severity of disease have a
pronounced effect on rCBF, especially that of the left parietal region.