Neuropsychological correlates of single photon emission computed tomography (SPECT) in Alzheimer's disease.

Examined associations between regional cortical perfusion on SPECT scans and cognitive test performance in 15 patients (mean age 67.1 yrs) with probable Alzheimer's disease (AD) of mild to moderate severity. The degree and extent of decreased perfusion of SPECT scans was associated with severity of AD and neuropsychological test scores correlated with findings of lateralized perfusion deficits on SPECT scans. Perfusion deficits on SPECT scans were also associated with estimates of global changes in intellectual functioning. Instruments included the Wechsler Adult Intelligence Scale—Revised (WAIS—R), the Mini-Mental State Examination, the Aphasia Screening Test, and the Trail Making Test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early diagnosis of herpes simplex virus encephalitis by single photon emission computed tomography (SPECT) in patients with normal MRI

Since treatment of herpes simplex virus encephalitis (HSVE) is most effective when started early, a sensitive and specific method for early diagnosis would be of great benefit. MRI and CT are commonly used for this purpose. In this study, we presented two patients who had serologically confirmed HSVE and had normal CT and MRI, but were diagnosed as having HSVE by means of SPECT in the early stage. Case 1 was a 56-year-old man who suddenly developed alexia. On admission, physical and neurological examination were unremarkable except for alexia, agraphia, acalculia, and left-right disorientation. Brain CT, MRI, and cerebral angiography were all normal. However, SPECT showed hyperaccumulation of 99m Tc-HM-PAO in the right temporal-occipital area. On the 5th hospital day, he became comatose. CSF study revealed marked pleocytosis. Even then, MRI including Gd-enhanced study was normal while SPECT continued to show hyperaccumulation. Detection of herpes simplex virus DNA in CSF by polymerase chain reaction was negative. Anti-HSV antibody titer in CSF and serum confirmed intrathecal production of the antibody on the 14th hospital day. Abnormal accumulation of tracer in SPECT returned to normal on the 31st day when he was alert but still had a mild Gerstman syndrome. Case 2 was a 61-year-old man with disturbance of consciousness, mental dysfunction, and generalized convulsion. He was diagnosed as having HSVE by means of CSF pleocytosis, detection of HSV DNA in CSF by polymerase chain reaction, and presence of anti-HSV antibody in the CSF. CT and MRI again revealed no abnormality while SPECT clearly showed hyperaccumulation in the left temporal lobe in an early stage. Hyperaccumulation of lipophilic tracer on SPECT study, especially in the temporal lobes, has been reported in the early stage of HSVE by previous investigators. Unlike MRI or enhanced CT, the increased tracer accumulation in SPECT does not reflect disruption of the blood-brain-barrier or inflammatory edema, but reflects hyperperfusion or some other HSVE related abnormality which is currently unknown. From these observations, we suggest that local hyperperfusion occurs before local inflammation, and that SPECT is the most useful scanning method for early diagnosis of HSVE when this disease is clinically suspected.     

Neural control of micturition in man examined with single photon emission computed tomography using 99mTc-HMPAO

THE neural mechanisms of micturition in man were studied using single photon emission computed tomography (SPECT). The areas activated during micturition, relative to the resting state, were the upper pons, the left sensorimotor cortex, the right frontal cortex and the bilateral supplementary motor areas. Some of these regions have been established by clinical and experimental studies as the neural control centre for voiding. We confirmed the neural micturition centre in healthy men using SPECT for the first time.     

Ictal single photon emission computed tomography in occipital lobe seizures

PURPOSE: Ictal single photon emission computed tomography (SPECT) has been evaluated as an adjunctive localizing technique in temporal lobe epilepsies and, to a lesser degree, in some extratemporal epilepsies. The purpose of this study was to determine whether occipital lobe seizures are associated with distinctive ictal cerebral blood perfusion (rCP) patterns. METHODS: SPECT was used with the tracer 99mTc HMPAO to image ictal rCP in 6 patients in whom clinical, EEG, and imaging data indicated occipital lobe seizures. RESULTS: Two patterns of rCP were seen. Four patients had hyperperfusion that was restricted to the occipital lobe, and two patients had hyperperfusion of the occipital lobe and the ipsilateral mesial temporal lobe, with hypoperfusion of the lateral temporal lobe. The latter 2 patients had clinical and surface EEG evidence of temporal lobe involvement in the seizure discharge. CONCLUSIONS: Ictal rCP patterns in occipital lobe seizures are distinct from those in temporal lobe seizures and may vary according to whether or not ipsilateral temporal lobe structures are involved in the ictal discharge.     

Parathyroid detection in secondary hyperparathyroidism with 123I/99mTc-sestamibi subtraction single photon emission computed tomography

123I/99mTc-sestamibi subtraction single photon emission computed tomography (SPECT) has been proposed to detect hyperplastic parathyroid tissue, but the clinical usefulness of this technique in secondary hyperparathyroidism is uncertain. The purpose of this study was to evaluate preoperative parathyroid localization using 123I/99mTc-sestamibi subtraction SPECT in patients with renal failure and secondary hyperparathyroidism. Nineteen patients with chronic renal failure and secondary hyperparathyroidism underwent 123I/99mTc-sestamibi subtraction SPECT imaging preoperatively. None of these patients had undergone previous neck surgery. The location, weight, and histopathological results of all identified parathyroid glands were recorded. Surgery was considered successful in all patients, with resection of a total of 74 hyperplastic parathyroid glands. 123I/99mTc-sestamibi subtraction SPECT correctly identified 57 of these parathyroid glands (77% sensitivity). The mean weight among the true positive glands (n = 57) was 1031 mg (range, 45-7900 mg), and that among the false negative glands (n = 17) was 465 mg (range, 20-1800 mg). This difference between the mean weights was statistically significant (P = 0.018). There was a positive correlation between parathyroid weight and detectability with 123I/99mTc-sestamibi subtraction SPECT (Spearman correlation = 0.28; P = 0.0167). 123I/99mTc-sestamibi subtraction SPECT is able to correctly localize hyperplastic parathyroid glands in patients with renal failure and secondary hyperparathyroidism, but there is a fairly weak relationship between preoperative detection rate and anatomical parathyroid gland size.     

A study of cerebral perfusion using single photon emission computed tomography in neonates with brain lesions

In this study we used a single photon emission computed tomography technique (SPECT) with radiolabelled 99mTcHMPAO to assess cerebral perfusion in newborn infants with documented cerebral lesions and to determine to what extent brain SPECT might be useful in the neonatal period. A total of 15 newborn infants with the following cerebral pathologies were enrolled: severe parietal bilateral periventricular leucomalacia (PVL, n = 6); moderate parietal bilateral PVL (n = 2); intraventricular haemorrhage grade II with unilateral parietal parenchymal extension (IHV + PE, n = 3); cerebral infarction (CI, n = 2) in the zone of middle cerebral artery; and post-haemorrhagic hydrocephalus (n = 2). Follow-up was available in all infants. Alterations in cerebral perfusion were seen in only 12 of 15 infants and at the location of severe PVL, PE and CI. We have noted that the regions of diminished perfusion extended beyond the apparent extent of cerebral pathology delineated by ultrasound or magnetic resonance imaging. Markedly diminished perfusion was seen in 1 infant with hydrocephalus, which recovered following placement of ventriculo-peritoneal shunt. Regarding outcome, SPECT data failed to provide additional information than that of neuroradiological investigations. We conclude that the use of SPECT, under these conditions, to assess alteration of cerebral perfusion in the neonatal period will not provide any additional information than that of neuroradiological investigations.     

Significance of single photon emission computed tomography and akinetic mutism]

Akinetic mutism is a reactive status with permanent opening of the eyes. The accountable lesions are always bilateral. The injured cerebral structures include the frontal gyri, the thalami or the mesencephalic areas. In one case of a 44-year-old patient, magnetic resonance imaging and computed tomography were not contributive. Tc99m brain SPECT imaging was performed and displayed bilateral frontal hypoactivity. This case suggests that this technique could be helpful for diagnosis when clinical features and radiological pattern are opposite.     

PASAT performance and the pattern of uptake of 99mTc-exametazime in brain estimated with single photon emission tomography

The effect of the paced auditory serial addition test (PASAT) on the regional uptake of 99mTc-exametazime was determined by single photon emission computed tomography. Twenty insulin-treated diabetic outpatients were scanned at rest and during the performance of the PASAT task using split-dose injection of tracer. When resting and activation scans were compared there were significant decreases in tracer uptake in the right anterior cingulate and left posterior cingulate areas during PASAT activation. The findings are compared with previous studies which had implicated the anterior cingulate area in the mechanisms of attention in humans and other animals. The potentially confounding role of anxiety during attentional tasks is discussed.     

Anti-CEA immunoscintigraphy might be more useful than computed tomography in the preoperative thoracic evaluation of lung cancer. A comparison between planar immunoscintigraphy, single photon emission computed tomography (SPECT), and computed tomography

While a clinical, plain radiographic, and bronchoscopic assessment yields most of the essential information needed in lung cancer, computed tomography (CT) of the thorax provides diagnostic information previously unobtainable, potentially capable of reducing the number of explorative thoracotomies. In a few recent studies, immunoscintigraphy with anti-carcinoembryonic antigen (anti-CEA) monoclonal antibodies (MA) has shown remarkable staging potential. To compare the diagnostic accuracy of the two techniques, we photoscanned with indium-111 (111In)-labeled-F(ab')2 fragments of the murine anti-CEA MA FO23C5 45 patients, who were pathologically assessed for possible loco-regional extension of lung cancer. Both planar and single photo emission computed tomography (SPECT) images were obtained. Additionally, CT of the thorax (contiguous CT slices, 10 mm thick, from the lung apices to the upper abdomen), and other routine tests of preoperative evaluation were obtained. On the basis of 37 (N1, T3, and T4), 38 (N2), and 12 (N3) pathologically documented sites, an accuracy of 65, 76, 92, 78, and 86 percent (SPECT images), and 62, 68, 42, 78, and 84 percent (CT images) was calculated (figures are relevant to N1, N2, N3, T3, and T4 disease, respectively). Thus, both techniques shared a significant margin of error in almost all the categories of evaluation; however, immunoscintigraphy showed equivalent, and, in the lymph node assessment, superior results to CT. A marginal improvement of diagnostic accuracy was recorded combining the three techniques in one case (SPECT plus planar immunoscintigraphic images), while there was no benefit in any possible integration of CT and immunoscintigraphic images. In patients with peripheral nonsquamous cell cancers, the accuracy of anti-CEA immunoscintigraphy was of 90 percent or higher. Variations in the modality of performing immunoscintigraphy, such as changes in the dose of antibody fragments to be injected, in the percentage of radiolabeling, or in the time of imaging, affected the quality of immunoscintigraphic series, and the consequent interpretation of findings. At the present time, there are very few reliable tests capable of selecting patients to proceed directly to thoracotomy or to receive some intermediate surgical test, such as a prior mediastinoscopy. Traditionally, CT has been this type of "filter-test." If current findings will be confirmed in future studies, anti-CEA immunoscintigraphy might replace CT in the evaluation of particular subgroups of patients, such as patients with peripheral nonsquamous cell bronchogenic carcinoma.     

Usefulness of electrocardiogram gated 99mTc-methoxy isobutyl isonitrile (MIBI) single photon emission computed tomography for detection of wall motion abnormality of left ventricle

The safety, tolerance and clinical effects of immunization with irradiated, allogeneic melanoma cells that express high levels of HLA-A1 and -A2 and secrete IL-2 after transfection with the Interleukin-2 gene, will be assessed in HLA-A1 or HLA-A2 positive melanoma patients with metastatic disease. As a pilot, the first 5-10 patients, if no immediate regression of tumor lesions are observed, will in addition to immunization with these allogeneic tumor cells receive recombinant IL-2 in relatively low doses during three consecutive weeks on an outpatient basis. If no clinical remissions are induced in these first 5-10 patients, subsequent 5-10 patients will receive the same dose of melanoma cells without additional rIL-2. Thereafter the dose of injected melanoma cells will be increased in every following 5-10 patients, but all subsequent patients will receive only IL-2 producing, allogeneic tumor cells, without the addition of rIL-2.     

Single photon emission computed tomography (SPECT) in a patient with bilateral temporal seizures: correlation between ictal EEG and postictal/ictal SPECT

We report a patient with bilateral independent temporal lobe seizures in whom two [99mTc]HMPAO single photon emission computed tomograph (SPECT) scans were performed during two different seizures. In the first periictal SPECT, [99mTc]HMPAO was injected in the interval between two closely spaced seizures (one localized in the left temporal lobe and the other in the right temporal lobe). SPECT images showed hypoperfusion in the left lateral temporal lobe, hyperperfusion of the left mesial temporal region, and pronounced hyperperfusion in the right anterior temporal lobe. These results suggest both a postictal left temporal SPECT pattern and an ictal right temporal pattern. In the second periictal SPECT, [99mTc]HMPAO was injected immediately after a right temporal lobe seizure and showed right lateral temporal lobe hypoperfusion and right mesial hyperperfusion, suggesting a postictal right temporal SPECT pattern. Interpretation of the periictal SPECT should take into account EEG changes at the time or in the minutes immediately after injection of [99mTc]HMPAO.     

Hypofrontality revisited: a high resolution single photon emission computed tomography study in schizophrenia

Hypofrontality or reduced activity in the prefrontal cortex, measured as reduced frontal perfusion or glucose uptake, has gained the status of an established finding in the medical literature on schizophrenia. Many relevant studies, however, have potential sources of bias, such as small subject numbers, or unreliable performance of activation tasks by the patients during the scanning procedure. Seventy patients with non-affective and non-organic psychoses were recruited--most qualifying for DSM III-R schizophrenia or schizophreniform psychosis (n = 60)--together with 20 healthy volunteers. They underwent single photon emission computed tomography with 99mTc-exametazime, carried out at rest. Tracer uptake was normalised to the occipital cortex. Group differences in tracer uptake were predicted in anterior regions of interest (prefrontal cortex and mesial frontal/cingulate cortex). Actively psychotic (including schizophrenic) patients not taking any drugs showed increased uptake in the prefrontal cortex. Reduced tracer uptake occurred in the mesial frontal cortex of schizophrenic patients, particularly if they were taking drugs. Relatively increased prefrontal tracer uptake associated with relatively decreased mesial frontal uptake characterised the patients in comparison with the controls. Generalised hypofrontality is, therefore, not a feature of schizophrenic patients at rest whether taking drugs or not.     

Usefulness of ictal and interictal 99mTc ethyl cysteinate dimer single photon emission computed tomography in patients with refractory partial epilepsy

OBJECTIVE: The aim was to investigate the feasibility of recording the electrical auditory brain stem response (EABR) evoked by electrical stimulation at the promontory (Prom-EABR) as a tool to assist selection of the ear for cochlear implantation in young children. STUDY DESIGN: The study group consisted of young children for whom the decision to proceed with implantation with the Nucleus mini 22-channel cochlear implant (Cochlear (UK) Ltd., London, UK) had already been made. SETTING: The Prom-EABR was recorded after the children had been anesthetised, but before the start of surgery. PATIENTS: A group of 25 children (11 boys and 14 girls), whose age at implantation ranged from 2 years 11 months to 6 years 8 months (mean age, 4 years 5 months), were investigated. INTERVENTION: Recordings of the Prom-EABR were used to determine which ear would receive the cochlear implant, providing there were no preexisting contraindications regarding selection of the ear. MAIN OUTCOME MEASURE: It has been suggested from earlier studies that the characteristics of the amplitude input/output (I/O) function of the EABR are related to neuronal survival. If the ear with the "better" I/O function is chosen for implantation, it might be expected that these children will perform better on average than those in whom the ear has been selected at random. RESULTS: Reliable recordings of the Prom-EABR were achieved in 40 ears (80%) of the 50 ears in the study. In 20 of the 25 children the technique was actively employed for selection of the ear for implantation. CONCLUSIONS: Recording of the Prom-EABR in the operating theater is a viable technique. Future analysis of long-term outcome measures of performance with the implant will confirm or dispute the benefit of ear selection using the Prom-EABR.     

18F]fluorodeoxyglucose single photon emission computed tomography: can it replace PET and thallium SPECT for the assessment of myocardial viability?

BACKGROUND: New high-energy collimators for single photon emission computed tomography (SPECT) cameras have made imaging of positron-emitting tracers, such as [18F]fluorodeoxyglucose (18FDG), possible. We examined differences between SPECT and PET technologies and between 18FDG and thallium tracers to determine whether 18FDG SPECT could be adopted for assessment of myocardial viability. METHODS AND RESULTS: Twenty-eight patients with chronic coronary artery disease (mean left ventricular ejection fraction [LVEF]=33+/-15% at rest) underwent 18FDG SPECT, 18FDG PET, and thallium SPECT studies. Receiver operating characteristic curves showed overall good concordance between SPECT and PET technologies and thallium and 18FDG tracers for assessing viability regardless of the level of 18FDG PET cutoff used (40% to 60%). However, in the subgroup of patients with LVEF< or =25%, at 60% 18FDG PET threshold value, thallium tended to underestimate myocardial viability. In a subgroup of regions with severe asynergy, there were considerably more thallium/18FDG discordances in the inferior wall than elsewhere (73% versus 27%, P<.001), supporting attenuation of thallium as a potential explanation for the discordant observations. When uptake of 18FDG by SPECT and PET was compared in 137 segments exhibiting severely irreversible thallium defects (scarred by thallium), 59 (43%) were viable by 18FDG PET, of which 52 (88%) were also viable by 18FDG SPECT. However, of the 78 segments confirmed to be nonviable by 18FDG PET, 57 (73%) were nonviable by 18FDG SPECT (P<.001). CONCLUSIONS: Although 18FDG SPECT significantly increases the sensitivity for detection of viable myocardium in tissue declared nonviable by thallium (to 88% of the sensitivity achievable by PET), it will occasionally (27% of the time) result in falsely identifying as viable tissue that has been identified as nonviable by both PET and thallium.     

Technetium-99m hexamethylpropylene amine oxime single photon emission tomography of the brain in early Parkinson''s disease: correlation with dementia and lateralization

In order to assess the seroepidemiology of protective antibodies against rubella among women from León, Guanajuato, Mexico, a prospective study was done. The sample consisted in 176 serum samples from urban and rural women at reproductive age, drawn from June 1990 to June 1991. Samples were tested by the classic hemagglutination inhibition method, titers of 1:8 or higher were considered as positive. Global positivity was 71 per cent (125 sera). Seropositivity did not increase with women's age; the lowest values were seen at the rural zones (58.9%). This survey showed a lower seropositivity than the previously reported in Mexico, and confirms data from new official studies. With this information authors suggest that the utility and viability of a national vaccination program should be reviewed and propose that it could be risky that individual clinicians to recommend children vaccination because the lack of coordination could increase adult cases of rubella.     

Reverse redistribution during dipyridamole thallium-201 myocardial single photon emission computed tomography in coronary artery disease

Ninety-six of the consecutive 1100 patients who underwent dipyridamole thallium-201 myocardial single photon emission computed tomography (SPECT) demonstrated reverse redistribution (RR). Twenty-six of the 96 cases who had accepted coronary angiographies were included in this study. RR was present in 40 myocardial segments from the 26 patients. Seventeen segments were in the right coronary artery (RCA) distribution, 17 in the left anterior descending artery (LAD) distribution, and 6 in the left circumflex artery (LCX) distribution. Perfusion defects noted on the initial study became more severe in the delayed images in 22 segments and normal perfusion was present during the initial images in 18 segments. Seventeen segments with RR were in the distribution of coronary arteries with abnormal angiographic findings. Of the remaining 23 segments, the angiographic findings were normal. In conclusion, RR can happen in TI -201 SPECT after dipyridamole and easily appears in the territories of RCA and LAD. It does not absolutely indicate whether the arteries are significantly diseased or normal coronary arteries.     

Reduced brain serotonin transporter availability in major depression as measured by [123I]-2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane and single photon emission computed tomography

BACKGROUND: Prior research has suggested reductions in the density of serotonin transporter (SERT) binding sites in blood platelets and post-mortem brain tissue of depressed patients. We sought to determine whether patients with unipolar major depression have diminished SERT availability as assessed by both brainstem [123I] beta-CIT SPECT and platelet [3H]paroxetine binding. METHODS: Drug-free depressed and healthy subjects were injected with 211 +/- 22 MBq [123I] beta-CIT and imaged 24 +/- 2 h later under equilibrium conditions. A ratio of specific to nonspecific brain uptake (V3" = (brainstem-occipital)/occipital), a measure proportional to the binding potential (Bmax/Kd), was used for all comparisons. RESULTS: Results showed a statistically significant reduction in brainstem V3" values in depressed as compared to healthy subjects (3.1 +/- .9 vs. 3.8 +/- .8, p = .02). Platelet [3H]paroxetine binding was not altered (Bmax = 2389 +/- 484 vs. 2415 +/- 538 fmol/mg protein, p = .91) and was not significantly correlated with brainstem [123I] beta-CIT binding (r = -0.14, p = .48). CONCLUSIONS: These data are the first to suggest reductions in the density of brain SERT binding sites in living depressed patients. These findings provide further support for a preeminent role for alterations in serotonergic neurons in the pathophysiology of depression.     

Prediction of 6-year prognosis for cardiac event by thallium-201 single-photon emission computed tomography (SPECT) with treadmill exercise test

To examine thallium-201 single-photon emission computed tomography (SPECT) with a treadmill exercise test can predict the long-term prognosis of patients with coronary artery disease, 95 patients (71 men, 24 women) who underwent a treadmill exercise test with thallium-201 SPECT from April to December 1986 were followed for 6 years. Three short-axis slices at the apical, mid- and basal-level were selected, and each slice was divided into eight segments. Each segment count was assigned a score according to the count range in the slice (score 0, count range 76-100%; 1, 51-75%; 2, 26-50%; 3, 1-25%; 4, 0%) by evaluating the mean value of the slice. The total T1 defect score of each segment in 3 slices was summed (sigma T1 defect score). The 'early sigma T1 defect score' was the sigma T1 defect score 5 min after treadmill exercise, and the 'late sigma T1 defect score' was sigma T1 defect score measured 4 h after treadmill exercise. Cardiac events occurred in 27 of the 95 patients: cardiac death 3; myocardial infarction 1; percutaneous transluminal angioplasty 16; coronary artery bypass graft 5; congestive heart failure 3. Univariate analysis showed that previous myocardial infarction (p < 0.01), exercise work load (p < 0.05), early sigma T1 defect score (p < 0.01) and late sigma T1 defect score (p < 0.01) were independent predictors of the prognosis. These results suggest that thallium-201 SPECT with the treadmill exercise test could be applicable and useful to predict long term prognosis.     

In vivo imaging of brain nicotinic acetylcholine receptors with 5-[123I]iodo-A-85380 using single photon emission computed tomography

The distribution and kinetics of 5-[123I]iodo-A-85380, a novel ligand for brain nicotinic acetylcholine receptors (nAChRs), were evaluated in the Rhesus monkey using single photon emission computed tomography (SPECT). Peak levels of radioactivity were measured in brain at 90 min after injection of the tracer. Accumulation of radioactivity was highest in the thalamus, intermediate in the frontal cortex and basal ganglia, and lowest in the cerebellum. The ratio of specific to nonspecific binding (V3") in the thalamus, estimated from the (thalamic-cerebellar)/cerebellar radioactivity ratio, reached a value of 6 at 4 h post-injection. Specific binding was reduced by subcutaneous injection of 1 mg/kg cytisine at 2.25 h after injection of radiotracer. At 2.5 h after cytisine administration, radioactivity in the thalamus was reduced by 84%, in the frontal cortex, by 76%, and in the basal ganglia, by 57% of the level measured at the time of cytisine administration, demonstrating that the binding was reversible. On the basis of these findings, together with other data indicating high affinity, receptor subtype selectivity, low nonspecific binding and lack of toxicity in animals, 5-[123I]iodo-A-85380 appears to be a promising ligand for SPECT imaging of nAChRs in the human brain.