99m Technetium-HMPAO-labeled platelet scan in practice: Preparation, quality control, and biodistribution studies

Abstract There is no biodistribution or imaging data on 99mtechnetium (Tc)-hexamethyl propylamine oxime (HMPAO)-labeled platelets in the literature. The current study aimed to present updated information about the clinical procedures for preparation and use of labeled platelets. Following two-step centrifugation at 1500 and 2500 rpm, the platelets were extracted from whole blood into platelet-rich plasma (PRP) above the buffy coat and then from PRP into a platelet pellet at the bottom of the tube. The 99mTc-HMPAO-labeled platelets were inspected for purity, viability, release of 99mTc from platelets, and sterility. Also, microscopic examination and thin layer chromatography (TLC) were performed. Biodistribution was assessed following necropsy in BALB/c mice and through imaging of New Zealand rabbits. The separation ratio was estimated at 98%, and radiochemical purity was measured to be 80%. The labeling efficiency was above 30% in more than half of the assays (range: 17-43%). The release of 99mTc from platelets was 9% per hour at 37ºC. After 24 hours, stability was estimated at 54% in the human serum. The target organs of mice included the spleen and liver. In rabbits, the imaging results indicated liver as the target organ. Thyroid uptake was negligible up to 90 minutes. Based on the findings, extraction of platelets and labeling them with 99mTc-HMPAO is a feasible and safe approach in routine practice.

Comparative Analysis of (99m)Tc-MDP Three-Phase Bone Scan with SPECT/CT and (99m)Tc-HMPAO-Labeled WBC SPECT/CT in the Differential Diagnosis of Clinically Suspicious Post-traumatic Osteomyelitis / 대한핵의학회잡지

PURPOSE: To identify differences between three-phase bone scan and SPECT/CT (TBS) and WBC SPECT/CT (WS) and compare diagnostic accuracies of each modality in patients with suspicious post-traumatic osteomyelitis (OM).METHODS: Twenty-one patients with suspicious post-traumatic OM were enrolled. All patients performed TBS and WS within 1 week. Foci ofMDP andWBC accumulation were divided into three categories: bone (OM), soft tissue (soft tissue inflammation; STI), negative for inflammation (NI). Confirmative diagnosis was made upon operative pathology or long-term clinical follow-up.RESULTS: Of 21 patients, four OM, eight STI, nine NI were finally diagnosed. TBS diagnosis was correct in three of four positive cases and nine of 17 negative cases. Sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV) of TBS were 75 %, 52.9 %, 57.1 %, 27.3 %, 90 %. WS diagnosis was correct in two of four positive cases and 17 of 17 negative cases. Sensitivity, specificity, accuracy, PPV, NPV were 50 %, 100 %, 81.0 %, 100 %, 89.5 %. Twelve of 21 cases showed agreement between TBS and WS. TBS misdiagnosed nine cases (six STI and two NI as eight OM; one OM as one STI), while WS misdiagnosed four cases (two OM as two STI; two STI as two NI). Combining results from TBS and WS led to better diagnostic accuracy (91.7 %) than either TBS or WS alone.CONCLUSION: TBS and WS showed moderate agreement in assessment of clinically suspected post-traumatic OM. WS better evaluated inflammation than TBS. WS tended to underestimate inflammation whereas TBS tended to overestimate inflammation. Combining TBS and WS enhanced diagnostic accuracy.

Clinical Usefulness of 99mTc-Hexamethyl Propylene Amine Oxime Perfusion Single Photon Emission Computed Tomography for Early Phase Multiple System Atrophy

BACKGROUND: Clinical diagnosis of multiple system atrophy (MSA) relays on signs and symptoms that are often difficult to identify particularly at early stage. Indeed neuropathological studies have demonstrated that Parkinson variant of MSA (MSA-P) is the first cause of misdiagnosis in a cohort of patients presenting with parkinsonian features. But accurate diagnosis of these disorders is important for deciding on treatment, appropriate advice and prognosis since atypical parkinsonian disorders are characterized by poor response to dopaminergic treatment and more rapid disease progression. Therefore, we conducted this study to investigate difference of perfusion Single Photon Emission Computed Tomography (SPECT) in patients with the early phase of MSA-P using SPM program. METHODS: We recruited consecutively 21 patients with MSA-P and 48 age-matched healthy controls. All subjects underwent Tc-99m HMPAO perfusion SPECT and this perfusion images were analyzed. RESULTS: For MSA-P, only hypoperfusion was seen in the middle frontal gyrus of left frontal lobe, superior frontal gyrus of right frontal lobe, precentral gyrus of left frontal lobe, middle frontal gyrus of right frontal lobe and precentral gyrus of right frontal lobe with respect to healthy subjects. CONCLUSIONS: We cautiously assume that perfusion SPECT may offer significant advantages compared to other imaging techniques in the assessment of neuronal degeneration in MSA-P and may help the clinician in the diagnostic characterization of patients presenting with atypical parkinsonism.

Efectos del consumo de marihuana en escolares sobre funciones cerebrales demostrados mediante pruebas neuropsicológicas e imágenes de neuro-SPECT / Effects of marihuana consumption in school children on brain functions demonstrated by means of neuropsychological tests and neuro-SPECT imaging

Comparative study based on 565 adolescent school children coming from four schools in the metropolitan area of Santiago, Chile. All were interviewed in order to select a sample that was stratified for sex, class and condition of consumer or non-consumer. The variables of intellectual coefficient and socioeconomical level were maintained constant. With this selection we conformed two groups: 40 consumers exclusively of marihuana and 40 non-consumers. We compared the results obtained in both groups in the neuropsychological tests while the neuroSPECT studies of consumers were compared against a normal database for the same age group. The adolescent consumers of marihuana demonstrate less cognitive capacity related to the process of learning such as attention, concentration, ranking, viso-spatial integration, immediate retention and visual memory. The differences between both groups are statistically significant. The findings of neuroSPECT demonstrate subgenual hypoperfusion bilaterally, more marked on the left side, in area 25 of Brodmann. This area controls mood. There is also frontal bilateral hypoperfusion (area 10 and area 32 of Brodmann). Area 32 is pre-anterior cingulate gyrus. Also hypoperfusion of the anterior cingulate gyrus (area 24 of Brodmann) and hypoperfusion of area 36 of Brodmann that projects over the hippocampus. Students that were consumers exclusively of marihuana demonstrate coincident abnormal findings of neuroimages and neuropsychological tests in areas of the brain related with learning and also significant differences between consumers with non-consumers in the neuropsychological tests.

Estudio comparativo basado en 565 escolares adolescentes pertenecientes a cuatro colegios de Santiago, Chile. Fueron encuestados todos para seleccionar una muestra estratificada por sexo, curso y condición de consumidores o no consumidores, manteniendo constante las variables coeficiente intelectual y nivel socioeconómico. Se conforman dos grupos: 40 consumidores exclusivos de marihuana y 40 no consumidores. Se comparan los resultados obtenidos en ambos grupos en los Test Neuropsicológios y del NeuroSPECT de consumidores con una base de datos considerados normales para el mismo grupo etario. Los adolescentes consumidores de marihuana evidencian menores habilidades cognitivas asociadas al proceso de aprendizaje, tales como atención, concentración, jerarquización, integración visoespacial, retención inmediata y memoria visual. Las diferencias entre ambos grupos son estadísticamente significativas. Los hallazgos del NeuroSPECT muestran hipoperfusión subgenual bilateral, más marcada en el hemisferio izquierdo (área 25 de Brodmann), hipoperfusión frontal bilateral (areas 10 y 32 de Brodmann), hipoperfusión del gyrus cingulado anterior (área 24 de Brodmann) e hipoperfusión del área 36 de Brodmann que proyecta sobre el hipocampo. Los estudiantes consumidores exclusivamente de marihuana muestran compromiso coincidente en neuroimágenes y test neuropsicológicos en áreas del cerebro relacionadas con el aprendizaje y se diferencian significativamente de los no-consumidores en las pruebas neuropsicológicas.

Cerebral Perfusion Abnormalities in Cases of Down Syndrome.

A SPECT (single photon emission computed tomography using Tc-99m HMPAO) study of brain with segmental quantitative analysis was conducted to access the cerebral perfusion in cases of Down’s syndrome (DS). Varying level of brain hypo-perfusion was documented, probably explaining the neurophysiologic basis of cognitive and neuropsychological deficits, which are not well understood in DS.

Changes in Cerebral Vascular Reserve Capacity after Carotid Artery Stenting: A 6-Month Follow-up Study

BACKGROUND: Assessment of cerebral vascular reserve capacity prior to carotid artery stenting is used for predicting hyperperfusion syndrome. However, the changes in vascular reserve capacity after carotid stenting are not fully understood. In this study we investigated the effects of carotid artery stenting on the restoration of vascular reserve capacity using (99m)TC-hexamethylpropylene amine oxime (HMPAO) single-photon-emission computed tomography (SPECT). METHODS: The study population comprised 29 patients who underwent carotid artery stenting. Patients were divided into groups according to occlusion of the contralateral internal carotid artery (unilateral group vs bilateral group) and according to the presence or absence of symptoms related to carotid stenosis (symptomatic group vs asymptomatic group). Pre- and postacetazolamide-activated (99m)TC-HMPAO SPECT were performed prior to stent insertion and at 1 and 6 months postoperatively. Vascular reserve capacity was assessed based on pre-, and 1- and 6-month postacetazolamide gamma count ratio (Post0, Post1, and Post6, respectively) and cerebrovascular reactivity (CVR0, CRV1, and CRV6, respectively). RESULTS: The postacetazolamide gamma count ratio and cerebrovascular reactivity tended to improve at 1 month after stenting, but tended to deteriorate at 6 months after stenting in the unilateral group compared with the bilateral group [Post0-Post1=0.045+/-0.078 (mean+/-SD), p=0.014; Post0-Post6=0.025+/-0.063, p=0.042; Post1-Post6=-0.020+/-0.047, p=0.102; CVR0-CVR1=0.043+/-0.071, p=0.008, CVR0-CVR6=0.019+/-0.063, p=0.097; CVR1-CVR6=-0.024+/-0.047, p=0.008] and in the symptomatic group compared with the asymptomatic group (Post0-Post1=0.058+/-0.106, p=0.038; Post0-Post6=0.048+/-0.103, p=0.061; Post1-Post6=-0.010+/-0.048, p=0.700; CVR0-CVR1=0.037+/-0.083, p=0.074; CVR0-CVR6=0.014+/-0.073, p=0.344; CVR1-CVR6=-0.023+/-0.054, p=0.055). CONCLUSIONS: The observed increases in postacetazolamide gamma count ratio and cerebrovascular reactivity at 1 month followed by decreases at 6 months may reflect the restoration of vascular reserve capacity. Carotid artery stenting can improve vascular reserve capacity, especially in patients with unilateral stenosis and with symptomatic stenosis.

Usefulness of hybrid SPECT/CT for the 99mTc-HMPAO-labeled leukocyte scintigraphy in a case of cranial osteomyelitis

Cranial osteomyelitis is a potentially fatal lesion. White blood cell scanning (WBC) with 99mTc-hexamethylpropylene amine oxime (HMPAO) has proven highly sensitive and specific in the diagnosis and follow-up of patients with suspected osteomyelitis. In this report we show the usefulness of SPECT and transmission CT performed simultaneously using a hybrid imaging device for the functional anatomic mapping of soft tissue and cranial bone infections. 99mTc-HMPAO-labeled leukocytes scintigraphy was performed on an elderly diabetic man with an intracranial mass lesion and with suspected temporal bone infection. Planar scans were acquired 30 min, 4 h, and 24 h after injection. SPECT/CT was obtained 6 h after tracer injection, using a dual-head camera coupled with a low-power X-ray tube. The scintigraphic results were matched with the results of surgery and of clinical follow-up. The planar images alone were true-positives for abscess in this patient. SPECT/CT improves the accuracy of99mTc-HMPAO scintigraphy especially in discriminating between soft-tissue and bone involvement. In fact, SPECT/CT also showed temporal bone osteomyelitis. This result indicates that SPECT/CT performed using a hybrid device can improve imaging with 99mTc-HMPAO-labeled leukocytes in patients with suspected osteomyelitis by providing accurate anatomic localization and precise definition of the extent of infection.

Characteristics of Brain Perfusion in Patients of Parkinson's Disease / 핵의학분자영상

PURPOSE: It was well known that cerebral blood perfusion is normal or diffusely decreased in the majority of patients with Parkinson's disease (PD). Actually we interpreted brain perfusion SPECT images of PD patients in the clinical situation, we observed various cerebral perfusion patterns in patients with PD. So we performed brain perfusion SPECT to know the brain perfusion patterns of PD patients and the difference of perfusion patterns according to the sex and the age. Also we classified PD patients into small groups based on the brain perfusion pattern. METHODS AND MATERIALS: Two hundred nineteen patients (M: 70, F: 149, mean age: 62.9+/-6.9 y/o) who were diagnosed as PD without dementia clinically and 55 patients (M: 15, F: 40, mean age: 61.4+/-9.2 y/o) as normal controls who had no past illness history were performed (99m)Tc-HMPAO brain perfusion SPECT and neuropsychological test. RESULTS: At first, we compared all patients with PD and normal controls. Brain perfusion in left inferior frontal gyrus, left insula, left transverse temporal gyrus, left inferior parietal lobule, left superior parietal lobule, right precuneus, right caudate tail were lower in patients with PD than normal controls. Secondly, we compared male and female patients with PD and normal controls, respectively. Brain perfusion SPECT showed more decreased cerebral perfusion in left hemisphere than right side in both male and female patients compared to normal controls. And there was larger hypoperfusion area in female patients compared with male. Thirdly, we classified patients with PD and normal controls into 4 groups according to the age and compared brain perfusion respectively. In patient below fifties, brain perfusion in both occipitoparietal and left temporal lobe were lower in PD group. As the patients with PD grew older, hypoperfusion area were shown in both frontal, temporal and limbic lobes. Fourthly, We were able to divide patients into small groups based on cerebral perfusion pattern. There was normal cerebral blood perfusion in 32 (14.7%) of 219 patients with PD, decreased perfusion on the frontal lobe in 45 patients (20.6%), the temporal lobe in 38 patients (17.4%), the parietal lobe in 39 patients (17.9%), the occipital lobe in 40 patients (18.3%), diffuse area in 14 patients (6.4%) and unclassified in 10 patients (4.6%). Fifthly, we compared the results of the neuropsychological test and cerebral perfusion pattern. There was no correlation between two tests except visuospatial function. CONCLUSION: Various perfusion state were found in patients with PD according to the age and sex. Also we were able to classify perfusion state into several groups and compare the neuropsychological test with cerebral perfusion.

The Value of (99m)Tc-HMPAO-WBC Scan in the Diagnosis of Infection after Total Knee Arthroplasty

PURPOSE: The early diagnosis and detection of prosthetic infection after TKA is very important and difficult for deter- mination of the plan in management and reduction of complications. In these reasons, this study was performed to evaluate the usefulness and limitation of (99m)Tc-HMPAO(Technetium (99m)-hexamethyl- propylene amine oxime)-labeled WBC scan in the patients with clinically suspicious prosthetic infection. MATERIALS AND METHODS: The study subjects were 25 patients(3 men and 19 women, mean age: 66.5 years) performed (99m)Tc-HMPAO WBC scan in the patients with clinically suspicious prosthesis infection after TKA from January, 2005 to May, 2007. And in 6 patients who had undergone bilateral arthroplasty, we regarded one patient as two cases. Thus, total 31 prostheses were included in this study. Final diagnosis of infection was based on bacteriological result by intrao- perative cultures, surgical findings, and histological evidence intraoperatively obtained in the suspicious site and clinical follow-up. RESULTS: In the final diagnosis, we confirmed that total 16 prosthetic joints were infected. Of these infected prostheses, increased (99m)Tc-HMPAO WBC scan uptake waspositive in 15, negative in 1. Finally, 15 cases were confirmed as nonin- fected prosthesis, 6 showed positive by (99m)Tc-HMPAO WBC scan uptake, 9 showed negative. Over all sensitivity, speci- ficity, and positive predictive value for diagnosisof infected TKA were 93.75, 60%, and 71.43%. CONCLUSION: (99m)Tc-HMPAO WBC scan was a highly sensitive method for the diagnosis of prosthetic infection after TKA. But low specificity and high false positive of (99m)Tc-HMPAO WBC scan demand more clinical follow-up for confirmed diagnosis. To increase specificity, additionally scan will be needed.

Application of SPM for Comparison of Striatal Dopamine Transporter Density between the Early Stage of the Parkinsonian Variant of Multiple System Atrophy and Parkinson's Disease

OBJECTIVE: Nigrostriatal dopaminergic neuronal degeneration is common to idiopathic Parkinson's disease(PD) and multiple system atrophy(MSA); although the topography of the nigral cell loss and striatal dopamine deficiency may differ. Currently, several functional neuroimaging techniques have been developed to differentiate between these two diseases. However, since the basal ganglia are usually poorly delineated in parkinsonian disorders on most functional neuroimaging techniques, most studies have failed to show the different pathologic changes among the parkinsonian disorders. In this study, we investigated alternation in regional loss of dopamine transporter binding using statistical parametric mapping(SPM) in patients with PD and the parkinsonian variant of MSA(MSA-P). METHODS: Ten PD and five MSA-P patients within 3 years of duration were studied with dual isotope brain SPECT following simultaneous injection of 370 MBq [99mTc] HMPAO and 111 MBq [123I] IPT. RESULTS: The basal ganglia were clearly visible on the fusion image, which was possible for quantitative and sta- tistical analysis. MSA-P patients showed significant loss of dopamine transporter binding in the left globus pallidus, anterior putamen and caudate nucleus in comparison to PD patients. CONCLUSION: This result may provide a useful tool to differentiate the pattern of loss of dopamine transporter bin- ding between PD and MSA-P.

A Case of Actinobacillus actinomycetemcomitans Bacteremia Associated with Permanent Pacemaker Lead Infection / 감염과화학요법

A 73-year-old man was admitted for intermittent episodes of fever and chills for 3 months. He had been implanted with a permanent pacemaker to control tachy-bradycardia syndrome 7 months before admission. Blood cultures were positive for Actinobacillus actinomycetemcomitans and a 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) WBC scan revealed inflammation on the pacemaker lead in extracardiac site. Oral examination revealed several dental caries. The patient was treated with intravenous ceftriaxone, followed by oral ciprofloxacin without removal of the infected pacemaker lead. He was doing well 10 months without febrile episodes after discontinuation of antibiotics. This report describes the first case of A. actinomycetemcomitans bacteremia associated with a pacemaker lead and localized by 99mTc-HMPAO WBC scan

A Case of Actinobacillus actinomycetemcomitans Bacteremia Associated with Permanent Pacemaker Lead Infection / 감염과화학요법

A 73-year-old man was admitted for intermittent episodes of fever and chills for 3 months. He had been implanted with a permanent pacemaker to control tachy-bradycardia syndrome 7 months before admission. Blood cultures were positive for Actinobacillus actinomycetemcomitans and a 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) WBC scan revealed inflammation on the pacemaker lead in extracardiac site. Oral examination revealed several dental caries. The patient was treated with intravenous ceftriaxone, followed by oral ciprofloxacin without removal of the infected pacemaker lead. He was doing well 10 months without febrile episodes after discontinuation of antibiotics. This report describes the first case of A. actinomycetemcomitans bacteremia associated with a pacemaker lead and localized by 99mTc-HMPAO WBC scan

Neurological Improvement after Cranioplasty in Patients with Surgical Bony Defects : The Usefulness of Acetazolamide Activated (99m)Tc-HMPAO SPECT

OBJECTIVE: The purpose of this study is to examine the influence of cranioplasty on dynamics of cerebral blood flow(CBF) and cerebrovascular reserve capacity(CVRC), and to investigate the usefulness of single photon emission computed tomography (SPECT) as a prognostic factor for neurological improvement after cranioplasty. METHODS: Between March 2003 and December 2005, a prospective study was performed on 24 patients who had undergone total 25 cranioplasty operations. Cerebral blood flow velocities in the middle cerebral artery(MCA) and internal carotid artery (ICA) were obtained by transcranial Doppler ultrasonography(TCD). The CVRC was assessed by SPECT in the natural state and after stimulation with 1g of acetazolamide. Neurological improvement after cranioplasty was compared between patients who showed hyperactivity to acetazolamide-activated SPECT (Group 1, n=7) and hypoactivity to acetazolamide-activated SPECT (Group 2, n=17). These measurements were obtained two weeks prior to and two weeks after cranioplasty. RESULTS: The blood flow velocities at the opposite site to the cranioplasty as well as at the cranioplasty site were significantly increased (P<0.05). Compared with Group 2, there was significant increase in CBF and neurological imrovement after cranioplasty in Group 1. CONCLUSION: Among patients with surgical bony defects, the patients who had normal reactivity of the CVRC showed a significant increase in CBF and neurological improvement after cranioplasty. The authors suggest that CVRC measurement prior to surgery may be an important prognostic factor for neurological improvement after cranioplasty.

Migration of 99mTc-Hexamethylpropylene Amine Oxime (HMPAO) Labeled Immature and Mature Dendritic Cells in the Mouse / 대한핵의학회잡지

PURPOSE: The purpose of this study is to evaluate migration of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labeled immature and mature dendritic cells (DC) in the mouse. METHODS: DC were collected from bone marrow (BM) of tibiae and femurs of mice. Immature and mature DC from BM cells were radiolabeled with 99mTc-HMPAO. To evaluate the functional and phenotypic changes of DC from radiolabeling, the allogeneic mixed lymphocyte reaction (MLR) and fluorescence-activated cell sorting (FACS) analysis were performed before and after labeling with 99mTc-HMPAO. Migration of intravenously injected DC (iv-DC) was assessed by serial gamma camera images of mice with or without subcutaneous tumor. Percent injected dose per gram (%ID/g) was calculated in lungs, liver, spleen, kidneys, and tumor through dissection of each mice after 24 hours of injection. RESULTS: Labeling efficiency of immature and mature DC were 60.4 +/- 5.4% and 61.8 +/- 6.7%, respectively. Iv-DC initially appeared in the lungs, then redistributed mainly to liver and spleen. Migration of mature DC to spleen was significantly higher than that of immature DC (38.3 +/- 4.0 % vs. 32.2 +/- 4.1 % in control group, 40.4 +/- 4.1% vs. 35.9 +/- 3.8 % in tumor group; p< 0.05). Migration to tumor was also significantly higher in mature DC than in immature DC (2.4 +/- 0.3% vs 1.7 +/- 0.2%; p=0.034). CONCLUSION: Assessment of migration pattern of DC in mice was possible using 99mTc-HMPAO labeled immature and mature DC. Migration of mature DC to spleen and tumor was higher than that of immature DC when they were i.v. injected.

A Case of Aorto-femoral bypass Graft Infection Complicated with Infective Endocarditis / 감염과화학요법

Prosthetic vascular graft infection (PVGI) is a relatively uncommon complication of peripheral vascular surgery and although rare, is the most severe complication in reconstructive vascular surgery. The early diagnosis of this complication can reduce the mortality. We report a case of aorto-femoral bypass graft infection, which was diagnosed by Tc-99m HMPAO WBC scan, complicated with infective endocarditis. A 60-year-old man had been operated with aortofemoral bypass graft because of aortojejunal fistula due to abdominal aortic aneurysm. Nine months later, he was admitted with fever of two months' duration. On echocardiolography, aortic regurgitation and vegetation were observed, and then he was diagosed with infective endocarditis. He was treated with antibiotics for 6 weeks. Recurrent bacteremia of unknown origin persisted despite antibiotic therapy. Multiple microorganisms were separately isolated from the blood cultures. He complained of intermittent right groin pain. Imaging study (CT, MRI, US) showed no definite evidence of graft infection. However, Tc-99m HMPAO WBC scan demonstrated uptake in the aortofemoral bypass graft site. The patient underwent emergent aortofemoral graft removal with axillobifemoral bypass and right femoropopliteal bypass.

A Case of Aorto-femoral bypass Graft Infection Complicated with Infective Endocarditis / 감염과화학요법

Prosthetic vascular graft infection (PVGI) is a relatively uncommon complication of peripheral vascular surgery and although rare, is the most severe complication in reconstructive vascular surgery. The early diagnosis of this complication can reduce the mortality. We report a case of aorto-femoral bypass graft infection, which was diagnosed by Tc-99m HMPAO WBC scan, complicated with infective endocarditis. A 60-year-old man had been operated with aortofemoral bypass graft because of aortojejunal fistula due to abdominal aortic aneurysm. Nine months later, he was admitted with fever of two months' duration. On echocardiolography, aortic regurgitation and vegetation were observed, and then he was diagosed with infective endocarditis. He was treated with antibiotics for 6 weeks. Recurrent bacteremia of unknown origin persisted despite antibiotic therapy. Multiple microorganisms were separately isolated from the blood cultures. He complained of intermittent right groin pain. Imaging study (CT, MRI, US) showed no definite evidence of graft infection. However, Tc-99m HMPAO WBC scan demonstrated uptake in the aortofemoral bypass graft site. The patient underwent emergent aortofemoral graft removal with axillobifemoral bypass and right femoropopliteal bypass.

Pharmacotherapy and Regional Cerebral Blood Flow in Children with Obsessive Compulsive Disorder

While regional cerebral blood flow (rCBF) studies on adults involving the caudate, prefrontal, orbitofrontal, and cingulated areas have been reported, no such published data on children exist. In this study, we aimed to determine the significance of pre- and post-treatment regional cerebral blood flow (rCBF) differences in children with obsessive compulsive disorder (OCD) and compared them with healthy controls. Eighteen drug-free obsessive compulsive children, aged 11 to 15, without comorbid states except for anxiety disorders - participated in this study. The control group consisted of 12 children, aged 11 to 15, with no medical or psychiatric illnesses. Using SPECT (Single Photon Emission Computerized Tomography) scans with Technetium-99m-HMPAO-hexamethly propyleneamine oxime (Tc99mHMPAO), the rCBF was calculated in 15 regions of the control group according to a standard protocol, while in the study group, it was measured at baseline and after 12 weeks of treatment with a fixed dose of paroxetine (20 mg qd). We compared the resulting pre- and post-treatment CBF values for the control group and study group. The right and left caudates, right and left dorsolateral prefrontals, and cingulate had significantly higher rCBF in children with obsessive compulsive disorder than in the control group. These areas, in addition to the right anteromedial temporal, showed significant rCBF reduction after treatment with paroxetine. The mean percentage of change in obsession scores during the treatment correlated significantly with the baseline and post- treatment rCBF level of the right caudate, post-treatment left caudate, and baseline left caudate. Our findings on children are consistent with adult studies and support the theory of a cortical-striatal-thalamic-cortical loop disturbance in OCD.

Effects of Hyperbaric Air Therapy on Cerebral Perfusion in Children with Cerebral Palsy

OBJECTIVE: To evaluate the effects of hyperbaric air therapy (HAT) on cerebral perfusion for children with cerebral palsy. METHOD: The protocol for HAT consisted of consecutive 10 days in which a child and his/her caregiver were held in 1.3 atm hyperbaric air chamber for 60 minutes per one day. Nine children with cerebral palsy underwent 99mTc-HMPAO single-photon emission computed tomography (SPECT) before and after HAT. The change of regional cerebral blood flow (rCBF) was evaluated by subtraction analysis using statistical parametric mapping. RESULTS: Average gestational age and birth weights were 34.0+/-5.1 months, and 2.3+/-1.2 kg, respectively. Two spastic quadriplegics, four spastic diplegics, two spastic hemiplegics, and one ataxic child were enrolled. In 3 out of 9 children, rCBF change was demonstrated; increased perfusion in right cerebellar hemisphere in child with diffuse brain atrophy and increased perfusion in diffuse cerebral cortex in child with left frontal leukoencephalopathy and decreased perfusion of right frontal cortex in child with right frontal leukoencephalopathy. CONCLUSION: These findings suggest that HAT may recruit less excitable neurons that was of functionally silent in motor cortex, previously. However, increased rCBF following HAT protocol could not be ruled out whether the result of learning effects or HAT.

Tc-99m HMPAO Brain Perfusion SPECT Findings in Acute Cerebellitis

Acute cerebellitis is an uncommon neurological complication that may occur following childhood viral infections, and is rarely reported in adults. Imaging studies show no abnormalities in the majority of cases. We experienced three cases of acute cerebellitis, which showed no abnormal findings on MRI, but revealed diffusely increased cerebellar per-fusions on brain perfusion SPECT, which normalized 5~6 months later. Therefore, brain perfusion SPECT is consid-ered to be useful in identifying acute cerebellitis and in monitoring its clinical course.

Synthesis of d- and l-Form of 99mTc-HMPAO, and Comparison of Brain Uptake / 대한핵의학회잡지

PURPOSE: 99mTc-HMPAO is a radiopharmaceutical for imaging cerebral blood flow. HMPAO (RR, SS)-4,8- diaza-3,6,6,9-tetramethylundecan-2,10- dione bisoxime) has three stereoismers such as, meso-, d-, and l-HMPAO. Techentium complexes of meso-HMPAO and d,l-HMPAO are known to have different in vivo brain uptakes. In this study, enantiomers of HMPAO (d-HMPAO and l-HMPAO) were separated from d,l-HMPAO. These enantiomers were labeled with 99mTc and the biodistribution studies were performed in mice. MATERIALS AND METHODS: An intermediate imine product was produced from 2,3-butanedione monooxime and 2,2-dimethyl- 1,3-propanediamine (54% yield) and was reduced into a mixture of three isomers (35% yield). The meso-isomer was separated from d,l-mixture by repeated fractional crystallization (11% yield). The d- and l-enantiomers were subsequently separated by co-crystallization with optical isomers of tartaric acid (25% and 5% yield, respectively). Each enantiomeric HMPAO was labeled with 99mTc by reacting with SnCl2 2H2O and 99mTc-pertechnetate. Biodistribution study was performed 1 hr after tail vein injection to ICR mice. RESULTS: Radiochemical purities of each compound were over 80%. In biodistribution study, the brain uptakes of d,l- d- and l-form were 1.34, 1.12 and 1.67% ID/g, respectively. In case of l-Isomer the brain uptake was higher (1.5 fold) than d-isomer. CONCLUSION: We successfully purified each enantiomeric HMPAO. In biodistribution study of stereoismers of 99mTc-HMPAO in mice, l-HMPAO may show better brain image than d,l-HMPAO which was supplied in a commercial kit.