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.     

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.     

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.     

Diagnosis and monitoring of cerebral hyperfusion after carotid endarterectomy with single photon emission computed tomography: case report

OBJECTIVE AND IMPORTANCE: Aortitis syndrome is a systemic vasculitis of unknown etiology, affecting mainly the major branches of the aorta and leading to stenosis or occlusion. Intracranial aneurysms are rarely associated with this syndrome. Only 15 cases have been previously reported. CLINICAL PRESENTATION: A 54-year-old woman with a 10-year history of aortitis syndrome demonstrated nonruptured cerebral aneurysms in the left internal carotid and anterior communicating arteries, with decreased flow in the right internal carotid artery and ipsilateral A1 segment. INTERVENTION: The patient underwent clipping of the aneurysms through a left pterional craniotomy and transsylvian approach. CONCLUSION: In our review of 16 reported cases, including the present case (13 with ruptured aneurysms and 3 with nonruptured aneurysms), there were 25 saccular aneurysms, and we noted the following clinical characteristics: 1) patient age was 26 to 64 years, with an average of 50.2 years; 2) aneurysms arose predominantly along the course of collateral flow, especially in the vertebrobasilar system (13 of 25 aneurysms, 52.0%); 3) there was a high incidence of multiplicity (7 of 16 cases, 43.8%). These characteristics suggest that increased hemodynamic stress, produced by stenosis or occlusion of the major branches of the aorta and systemic hypertension, plays an important role in the development of cerebral aneurysms in patients with this syndrome.     

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)     

The resting and activation issue of hypofrontality: a single photon emission computed tomography study in neuroleptic-naive and neuroleptic-free schizophrenic female patients

BACKGROUND: Functional neuroimaging findings of "hypofrontality" in schizophrenic patients is still controversial, due to the heterogeneity of methods and patient samples. This study tries to prevent some of these concerns by studying neuroleptic-naive (NN) and neuroleptic-free (NF) young female patients both in resting conditions and during a frontal cognitive activation task. METHODS: Regional cerebral blood flow (rCBF) was studied at rest and during the Wisconsin Card Sorting Test (WCST) in 25 young acute unmedicated schizophrenic female patients (14 NN and 11 NF) and 15 female controls, using single photon emission computed tomography. RESULTS: The schizophrenic and control groups did not differ in rCBF during the baseline condition, but the schizophrenic group failed to activate the frontal lobe during the WCST condition. In addition, the left anterior temporal rCBF at rest correlated with the Scale for the Assessment of Positive Symptoms total score. CONCLUSIONS: The results suggest that hypofrontality in young acute unmedicated schizophrenic patients is a result of an inability to activate frontal regions during cognition, rather than a baseline decrease in frontal activity. Furthermore, positive symptoms seem to be associated with left temporal cortex activity.     

Quantitative gated single photon emission computed tomography imaging: a counts-based method for display and measurement of regional and global ventricular systolic function

There is a considerable amount of data indicating that several major unfavorable cerebrovascular events are not randomly distributed over time, but show a peculiar distribution along the day, the week, and the months of the year. The authors review the available evidence on the chronobiological (circadian, weekly, and seasonal) patterns of onset of acute cerebrovascular diseases and variations in their possible triggering mechanisms. The existence of a peculiar chronobiological pattern in the onset of acute cerebrovascular disease, characterized by both circadian (morning and evening occurrence), circaseptan (last and first days of the week), and circannual (especially in winter) is confirmed, although differences depending on biological (gender, age), pathological (diabetes, hypertension, smoke, alcohol), cultural, social, and environmental factors exist. A deeper knowledge of the underlying pathophysiologic mechanisms could provide more effective insights for both preventive strategies and optimization of therapeutic approach.     

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.     

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.     

Tc-99m-HMPAO single photon emission computed tomography (SPECT) as an ancillary test in the diagnosis of brain death

Lipomatosis has not previously been reported in minor salivary glands. Its occurrence in the parotid gland is well recognized. We present the first reported case of lipomatosis of the minor salivary glands in the nasal cavity. We also review the tumours of the minor salivary glands, lipomas and lipomatosis of the parotid, and the few reported cases of lipomas of the sinonasal tract.     

201Tl single photon emission tomography in the evaluation of residual and recurrent astrocytoma

Twenty-five patients with malignant astrocytoma, either postoperatively (15 cases) or with recurrent tumour versus gliosis (10 cases) were included in this study. 201Tl single photon emission computed tomography (SPECT) was performed with the calculation of early and delayed uptake values and retention index. A high mean value of early and delayed uptake correlated with a low retention index in patients with high-grade astrocytoma in both postoperative residual and recurrent groups, versus a lower mean value of early and delayed uptake with a high retention index in patients with low-grade tumours. All postoperative cases with high-grade astrocytoma had high 201Tl uptake > 1.5, whereas 66.6% of cases with low-grade astrocytoma had low 201Tl uptake < 1.5. There was a correlation between retention index of 201Tl and tumour grade with r = 0.47. Also, recurrent cases showed remarkable differences in early and delayed 201Tl uptake (P < 0.05) and retention index (P < 0.001) compared with postradiation gliosis. There was a higher sensitivity in detection of tumour viability by 201Tl SPECT of 100% versus 80% using computed tomographic scanning and in the differentiation between recurrent tumour and postradiation gliosis.     

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.     

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.     

Utility of stress single-photon emission computed tomography (SPECT) perfusion imaging in predicting outcome after coronary artery bypass grafting

Previous studies have examined the predictors of outcome in medically treated patients with coronary artery disease (CAD). There is limited information on predictors of outcome after coronary artery bypass grafting (CABG). This study examined the predictors of outcome of 255 patients with CAD, at a mean time of 5 years after CABG for angina pectoris. The 255 patients underwent coronary angiography and stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging after CABG. During a mean follow-up of 41 +/- 28 months after stress testing, there were 34 hard events (24 cardiac deaths and 10 nonfatal myocardial infarctions). The hemodynamics during stress testing, and age and gender were not predictors of events. The SPECT variables of multivessel perfusion abnormality, perfusion deficit size, and increased lung thallium uptake were predictors of death and total events by uni- and multivariate survival analysis. There were 14 events in 45 patients (31%) with multivessel abnormality and increased lung thallium uptake, 14 events in 101 patients (14%) with either multivessel abnormality or increased lung uptake, and 6 events in 109 patients (6%) with neither of these 2 variables (p = 0.0001). The annual mortality and total event rates were 7.5% and 9.5% with both variables, 3.4% and 4.3% with either variable, and 0.6% and 1.7% with neither of the variables (p = 0.01). Thus, stress SPECT perfusion imaging is useful to stratify patients after CABG into low, intermediate, and high risk groups for future cardiac events.     

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.     

Demonstration of dose-dependent global and regional cocaine-induced reductions in brain blood flow using a novel approach to quantitative single photon emission computerized tomography

OBJECTIVE: To compare the effect of restoration of duodenal continuity by a Roux-en-Y oesophagojejunostomy with or without a pouch on nutritional state, growth, and morphology after total gastrectomy in pigs. DESIGN: Experimental study. SETTING: Teaching hospital, Sweden. MATERIAL: 60 Swedish domestic pigs. INTERVENTIONS: 54 pigs underwent total gastrectomy and 6 had sham operations. 20 pigs had reconstruction by a Roux-en-Y oesophagojejunostomy, 21 had a jejunal loop interposed between the oesophagus and the duodenum, as 13 had a oesophagojejunostomy with jejunal pouch on a Roux-en-Y loop. MAIN OUTCOME MEASURES: Weight, laboratory indicators of nutritional state, and histological appearance of the gut. RESULTS: Growth was significantly retarded in those pigs that had had gastrectomies (p < 0.001) but there were no differences among the experimental groups. Haemoglobin, albumin, and calcium concentrations were significantly lower in the experimental groups than in the control group (p=0.006, 0.02, and 0.002, respectively). Histological examination showed subtotal villous atrophy in the experimental groups, most obvious in the pouch group. Colonic mucosal height was reduced in the experimental groups. CONCLUSION: This study failed to show any advantage in growth rate when restoration of duodenal continuity or a small bowel pouch were compared with a conventional Roux-en-Y oesophagojejunostomy after total gastrectomy. However, restored duodenal passage seemed to benefit calcium homeostasis.