Quantitative assessment of cerebral hemodynamics using single photon emission computed tomography with venous blood sampling

Objective

Quantitative cerebral blood flow (CBF) measured by single photon emission computed tomography (SPECT) with arterial blood sampling is one of the most reliable methods to assess the hemodynamics in individual patients. SPECT with venous blood sampling is less invasive. The present study compared the measurement of CBF using N-isopropyl-p-(iodine-123)-iodoamphetamine SPECT with venous blood sampling and with arterial blood sampling in patients with major cerebral artery occlusive disease.

Methods

Two normal subjects and 14 patients with major cerebral artery occlusive disease underwent SPECT with arterial and venous blood sampling. The microsphere method was used for quantitative SPECT imaging. Whole brain radioactivity was corrected when the detectors rotated in the forward direction (F₁–F₇). Venous sampling was performed 30 min after radiotracer injection. Arterial blood radioactivity was estimated by multiple regression analysis from these parameters. The cerebrovascular reactivity to acetazolamide was also measured.

Results

Multiple regression analysis established the following formula:

Ca₁₀=−1.099F₁+1.629F₂−2.143F₃−2.766F₄−1.208F₅+2.113F₆+3.259F₇+1.241Cv₃₀+94.958${\text{Ca}}_{10}=-1.099{\text{F}}_1+1.629{\text{F}}_2-2.143{\text{F}}_3-2.766{\text{F}}_4-1.208{\text{F}}_5+2.113{\text{F}}_6+3.259{\text{F}}_7+1.241{\text{Cv}}_{30}+94.958$     

抑郁症患者局部脑血流灌注变化研究

目的 分析抑郁症患者单光子发射型计算机断层显像(SPECT)局部脑血流(SCBF)灌注变化的特点,并初步探讨rCBF显像在抑郁症患者中的诊断价值. 方法 对10例正常人及临床诊断为抑郁症的32例患者分别进行SPECT局部脑血流灌注显像,利用感兴趣区(ROI)法观察rCBF情况;11例患者同期行MRI普通扫描.结果 32例抑郁症患者中31例发现rCBF显像异常,共检出71个病灶,分别位于双侧额叶、颞叶、基底节、海马、扣带回及左侧岛叶,其中57个病灶位于颞叶、海马、扣带回及岛叶,即边缘系统,9个病灶位于额叶,5个病灶位于基底节;基底节区病灶局部脑血流灌注均增高,其他部位病灶均降低;双侧大脑半球rCBF病灶构成比差异无统计学意义(χ~2=409,P=0.790).11例患者同期做MRI扫描,3例发现异常(2例轻度脑萎缩,1例海马萎缩),而此11例患者rCBF显像均发现异常.1例正常人rCBF未发现异常显像.结论 大多数抑郁症患者存在脑边缘系统rCBF降低,部分患者存在基底节区rCBF增高.SPECT能敏感地发现抑郁症患者rCBF灌注的变化,对抑郁症的诊断具有一定的价值.     

99mTc-MIBI断层显像对脑胶质瘤的诊断价值研究

目的　探讨99mTc 甲氧基异丁基异腈 (MIBI)断层显像 (SPECT)对幕上脑胶质瘤的诊断价值。方法　 5 3例脑胶质瘤患者中 ,高度恶性脑胶质瘤 31例 ,低度恶性 2 2例 ,注射 740～ 930MBqMIBI 15分钟后行SPECT检查并重建冠状面、矢状面、横断面图像。MIBI的摄取指数计算为病灶区与对侧相同部位正常脑组织计数的比值。结果　高度恶性脑胶质瘤MIBI摄取指数为 1.9～ 6 .6 (平均 3.6± 1.4) ,低度恶性胶质瘤为 0 .8～1.7(1.1± 0 .2 ) ,两组比较P <0 .0 1。结论　99mTc MIBI断层显像对于幕上高度恶性和低度恶性脑胶质瘤的鉴别有一定的临床价值     

Single photon emission computerized tomography during and between seizures

Summary In three patients, patterns of brain activity were measured by ^99mTc-hexamethyl-propyleneamineoxime (^99mTc-HM-PAO) brain SPECT (single photon emission computerized tomography) in ictal and interictal states. Increased relative blood flow indicated the focus of partial seizures, its spreading to adjacent cortical regions and to distant brain structures via neuronal pathways. Ictal patterns of regional cerebral blood flow (rCBF) were in agreement with clinical symptomatology. Successive SPECT studies were performed after 3–7 days in the absence of electroencephalographic and clinical signs of seizures but still revealed increased relative blood flow in the focus of the seizures. SPECT studies, performed 2–6 weeks after the last clinically observable seizures, demonstrated the transition from increased to decreased relative blood flow in the focus of the seizures. In one patient, the EEG was complementary to and corresponded with the rCBF patterns in the ictal state. However, the dynamics of interictal changes could only be assessed by brain SPECT.     

Longitudinal study of cerebral blood flow in Alzheimer's disease using single photon emission tomography

Ten patients with probable Alzheimer's disease were assessed at baseline and a mean 2 years later using a battery of neuropsychological tests, CT scans and Tc99m-HMPAO SPECT scans. The subjects had declined significantly in their functional indices. Cerebral perfusion measures declined in the parietal lobes, left hemisphere and whole brain, but the overall decline did not reach statistical significance. The decline in brain perfusion did not correlate significantly with the decline in various indices of neuropsychological function, either globally or for specific brain regions. The index of cerebral perfusion correlated significantly with global indices of neuropsychological function at baseline but not at follow-up. No single perfusion index was a significant predictor of clinical progression of dementia.     

Ictal single photon emission computed tomography in seizures induced by eye closure

Ictal single photon emission computer tomography (SPECT) studies were performed on a 12 year old child with reflex seizures induced by eye closure. EEGs had shown generalised polyspike waves during eye closure. A magnetic resonance head scan was normal. There was no photosensitive induction of the seizure. Comparison between ideal and post treatment (ethosuximide) interictal SPECT revealed increased ictal perfusion in the basal ganglis, lateral frontal region and superior temporal lobe in the left hemisphere. It is suggested that the reflex epilepsy in this case was triggered by sensory afferents from the orbicularis oculi and mediated via the thalamus.     

应用单光子发射计算机体层摄影术研究药物滥用对人脑纹状体多巴胺转运体的损害

目的　在分子水平上研究摇头丸和海洛因滥用对人脑纹状体多巴胺转运体(DAT)的损害。方法　对健康对照组21名、摇头丸组12例、海洛因组43例进行单光子发射计算机体层摄影术检测。静脉注射显像剂99Tcm TRODAT 1剂量为740MBq/ml。计算纹状体的体积、质量、纹状体与全脑放射性比值(Ra% )和差值率(% )。结果　对照组双侧纹状体呈典型“熊猫眼”形,双侧尾状核和豆状核大致等大,DAT分布均匀、对称。摇头丸组和海洛因组纹状体的体积分别为(21 4±4 5)cm3 和(21 3±4 4)cm3,小于对照组[ ( 32 0±2 2 )cm3;P<0 01 ];质量分别为( 23 7±3 9 )g和( 22 4±3 2)g,低于对照组[ (33 6±2 6)g;P<0 01];Ra%分别为(5 9±0 8)%和(5 2±0 9)%,亦低于对照组[ (7 6±2 0)%;P<0 05],摇头丸组和海洛因组纹状体与全脑放射性比值与对照组的差值率分别是22 03%和30 74%。结论　滥用摇头丸和海洛因均破坏脑纹状体多巴胺能神经元的功能,DAT的数量、密度、分布和活性减低。     

Acute effect of electroconvulsive therapy on brain perfusion assessed by Tc99m-hexamethylpropyleneamineoxim and single photon emission computed tomography

Regional cerebral blood flow (rCBF) was measured in relative terms with Tc99m-hexamethylpropyleneamineoxim and single photon emission computed tomography in 11 patients undergoing electroconvulsive therapy (ECT). The patients suffered from major depressive disorder (n = 8) or schizoaffective disorders (n = 3). rCBF was measured under general anesthesia 3 days prior to the ECT treatment and coinciding with the ECT stimulation. ECT caused a redistribution of the tracers uptake. The uptake became more pronounced in frontal parts of the brain and in the basal ganglia than in posterior parts of the cortex, and the thalamus. This selective effect of ECT on rCBF may be related to catecholaminergic projections to anterior parts of the brain.     

Regional cerebral blood flow in patients with orally localized somatoform pain disorder: a single photon emission computed tomography study

Aim: Somatoform pain disorder is characterized by persistent and chronic pain at one or more sites without an associated general medical condition and in which psychological factors are thought to play a role. This study aimed to investigate the pathological features of somatoform pain disorder localized to the oral region by single photon emission computed tomography (SPECT). Methods: Ten patients (nine females and one male; average age 55.0 ± 14.4 years) having somatoform pain disorder with oral symptoms participated. SPECT was performed using N‐isopropyl‐4‐[¹²³I] iodoamphetamine intravenous injections, and regional cerebral blood flow (rCBF) was assessed by three‐dimensional stereotactic surface projections. We also selected 12 healthy individuals (seven females and five males; average age 61.8 ± 13.2 years) to act as controls. Results: Both the patient and control groups showed no atrophy or infarction on CT or magnetic resonance imaging. The patient group showed higher rCBF in the subcortical area, especially in the thalamus and cingulate gyri, than the control group. In contrast, the patient group showed lower rCBF in the bilateral frontal and occipital lobes as well as in the left temporal lobe. Conclusions: These results suggest that the biological process involved in somatoform pain disorder of the oral region is characterized by changes in limbic and cortical functions. The finding that somatoform pain disorder with oral symptoms is associated with brain functional changes will help to develop treatment regimes for this disorder and clarify the underlying pathology.     

Cerebral blood flow in spinocerebellar degenerations: a single photon emission tomography study in 28 patients

We used single photon emission tomography to study regional cerebral perfusion in patients with different forms of spinocerebellar degeneration: 6 patients with Friedreich’s ataxia (FA), 6 with early-onset cerebellar ataxia with retained tendon reflexes (EOCA), 5 with autosomal dominant cerebellar ataxia type 1 (ADCA I) and 11 with idiopathic late-onset cerebellar ataxia (ILOCA). The results were related to clinical and magnetic resonance imaging (MRI) findings. Cerebellar hypoperfusion was constant in ADCA I and frequent in patients with other spinocerebellar degenerations. Brain stem hypoperfusion was constant in ADCA I, frequent in ILOCA patients with pontocerebellar atrophy and absent in FA and EOCA. FA and EOCA often showed a reduction in the parietotemporal cortex blood flow, which was not related to cortical atrophy. ILOCA patients had an asymmetric pattern in the temporal areas with decreased blood flow in the right side only. Caudate hypoperfusion was found in ADCA I patients. Cerebral atrophy did not account for changes in regional blood flow, which probably indicate early involvement of cerebral structures. Received: 26 August 1997 Received in revised form: 22 January 1998 Accepted: 27 January 1998     

Cerebral perfusion inhomogeneities in schizophrenia demonstrated with single photon emission computed tomography and Tc99m-hexamethylpropyleneamineoxim

Cerebral blood flow was measured in relative terms with Tc99m-hexamethylpropyleneamineoxim (HMPAO) and single photon emission computed tomography (SPECT) in 28 female schizophrenic patients (20 acute and 8 chronic) classified according to DSM-III. Eleven normals served as controls. The acute patients were classified according to positive and negative symptoms. Patients with predominantly positive symptoms showed by and large normal and homogeneous cerebral isotope uptake. Those with negative symptoms, and the chronic patients, showed inhomogeneous tracer uptake with multiple regions of hypoperfusion in slices 4-6 cm above the orbitomeatal line. The findings support in principle the notion that schizophrenia with negative or chronic symptoms does not affect the whole brain homogeneously. Brain imaging with Tc99m-HMPAO and SPECT might be used to distinguish various types of schizophrenia.     

Cerebral blood flow changes in general paresis following penicillin treatment: a longitudinal single photon emission computed tomography study

Three cases of general paresis were successfully treated with high-dose penicillin. In all cases, cerebrospinal fluid cell counts decreased to normal and mental status improved rapidly. Cerebrospinal fluid protein concentrations decreased and IQ scores and overall levels of functioning improved gradually over 1 year. Regional cerebral blood flow (CBF) changes were analyzed longitudinally for 1 year using single photon emission computed tomography (SPECT). Autoradiography method and region of interest (ROI) analyses were used for quantitative CBF assessment and 3D stereotactic surface projections (3D-SSP) analyses were used for qualitative CBF pattern assessment. 3D-SSP could not reveal remarkable CBF pattern changes through the courses. The ROI analyses showed remarkable CBF decreases in all brain regions 1 month after the treatment, which recovered to normal levels 1 year after the treatment. These results suggest that remarkable decreases of quantitative CBF counts reflect the disappearance of encephalitis, while their gradual recovery reflects the gradual improvement of cerebral functional activity. As Treponema pallidum infection affects whole brain and CBF changes globally, quantitative CBF assessment may be more efficient than qualitative CBF pattern analyses for the purpose of understanding the pathophysiology of general paresis.     

Amlodipine lowers blood pressure without significant effect on cerebral blood flow in hypertensive patients with a history of stroke: a quantitative single photon emission computed tomography study

Appropriate antihypertensive therapy is important to prevent cerebrovascular disease. The purpose of the present study was to investigate the effect of such therapy on cerebral blood flow in stroke patients. Twenty hypertensive patients with a history of ischemic stroke received amlodipine 2.5 or 5 mg daily for 12 weeks. Blood pressure and cerebral blood flow as measured by ¹³³Xe single photon emission computed tomography at baseline and were compared at 12 weeks. There were statistically significant reductions in both systolic (167.0 to 140.9 mm Hg) and diastolic (97.8 to 81.8 mm Hg) blood pressures after 12 weeks of amlodipine treatment. No statistically significant effect was observed on cerebral blood flow (46.7 to 46.9 ml/100g brain/min). A weak but statistically significant change was observed in cerebellar blood flow (44.1 to 46.9 ml/100g brain/min). We concluded that amlodipine reduces blood pressure without affecting cerebral blood flow in hypertensive patients with a history of ischemic stroke. Investigation about its effect on cerebellar blood flow is mandatory.     

Establishment of a brain perfusion single photon emission computed tomography database in children by statistical imaging analysis

We made a 3-dimensional, 99mTc-ECD brain perfusion single photon emission computed tomography (SPECT) database in children by a statistical analysis. We selected 52 individuals between 1 and 15 years of age whose brain SPECT and brain MRI findings were normal, and divided them into three age groups: 1-5, 6-10 and 11-15 years. By comparing databases obtained for each group, an age-dependent change of regional cerebral blood flow was investigated. The results showed that the relative blood flow increases in the frontal lobe and cerebeller hemisphere and decrease in the occipital lobe with increasing age, findings consistent with those of previous reports. This database enabled us to easily find 3-dimensional brain perfusion abnormality in individual patient by SPECT, and may help elucidate the pathophysiology of many brain disorders.     

Iodine-123 labeled reboxetine analogues for imaging of noradrenaline transporter in brain using single photon emission computed tomography

Preliminary investigation of the radioiodinated (S,S)‐reboxetine analogue, ¹²³I‐INER, in baboons showed this tracer to have promise for imaging the noradrenaline transporter (NAT) using single photon emission computed tomography (SPECT). More recently, the radioiodinated (R,S)‐stereoisomer of ¹²³I‐INER, ¹²³I‐NKJ64, has been synthesized and preliminary evaluation in rats has been reported. This article reports the brain distribution and pharmacokinetic properties of ¹²³I‐NKJ64 in baboons and compares results with ¹²³I‐INER data in the same species. SPECT studies were conducted in two ovariectomized adult female baboons using two different protocols: (1) bolus of ¹²³I‐INER or ¹²³I‐NKJ64; and (2) bolus plus constant infusion of ¹²³I‐NKJ64 with reboxetine (2.0 mg/kg) administration at equilibrium. Following bolus injection, both radiotracers rapidly and avidly entered the baboon brain. The regional brain accumulation of ¹²³I‐NKJ64 did not match the known distribution of NAT in baboon brain, contrasting with previous results obtained in rats. Conversely, the regional distribution of ¹²³I‐INER was consistent with known distribution of NAT in baboon brain. No displacement of ¹²³I‐NKJ64 was observed following administration of reboxetine. This contrasts with previous data obtained for ¹²³I‐INER, where 60% of specific binding was displaced by a lower dose of reboxetine. These data suggest that ¹²³I‐NKJ64 may lack affinity and selectivity for NAT in baboon brain and ¹²³I‐INER is the most promising iodinated reboxetine analogue developed to date for in vivo imaging of NAT in brain using SPECT. This study highlights the importance of species differences during radiotracer development and the stereochemical configuration of analogues of reboxetine in vivo. Synapse 66:923–930, 2012. © 2012 Wiley Periodicals, Inc.     

强迫症与抑郁症的脑单光子发射计算机断层扫描对照研究

目的探讨强迫症、抑郁症局部脑血流量(rCBF)特点。方法应用单光子发射计算机断层扫描(SPECT)技术,对首发且未经治疗的39例强迫症患者、36例抑郁症患者和39名正常人于静息状态下行脑血流显像。以小脑皮质的放射性计数值为参考,对局部脑血流进行半定量分析。结果强迫症组两侧前额叶、前颞叶rCBF高于正常组(P<0.01);抑郁症组两侧前额叶、枕叶、扣带回及右前颞叶、右顶叶rCBF低于正常组(P<0.05);在两侧前额叶、前颞叶、顶叶、枕叶及右后额叶、扣带回,强迫症组rCBF高于抑郁症组(P<0.05)。结论强迫症组的前额叶及前颞叶呈高灌注改变,抑郁症组脑血流普遍低灌注,SPECT技术可望作为二者鉴别诊断的客观依据之一。     

Regional cerebral blood flow in chronic alcoholics measured by single photon emission computerized tomography

Regional cerebral blood flow (CBF) was measured by single photon emission computerized tomography of inhaled 133-Xe in 20 chronic alcoholic men. Mean CBF was 51 ml/(100 g x min) compared with 53 ml/(100 g x min) in 20 normals. Reduced cerebellar blood flow correlated both to structural abnormalities seen on CT scan and to cognitive dysfunction. Slight abnormalities of the regional CBF was observed in the alcoholics. They had a higher incidence of regional low flow areas than a control group. Low flow areas were found in frontal and posterior parts of the brain not only in patients with atrophia, but also in patients without CT abnormalities, suggesting neuronal dysfunction. The occurrence of regional low flow areas was associated with the severity of alcoholism, cerebral atrophy and intellectual impairment.     

Quantitative evaluation of regional cerebral blood flow changes during childhood using 123I-N-isopropyl-iodoamphetamine single-photon emission computed tomography

Objective

To quantitatively evaluate regional cerebral blood flow (rCBF) and regional developmental changes during childhood using ¹²³I-N-isopropyl-iodoamphetamine single-photon emission computed tomography (SPECT) and autoradiography.

Differential patterns of dopamine transporter loss in the basal ganglia of progressive supranuclear palsy and Parkinson's disease: analysis with [(123)I]IPT single photon emission computed tomography

The phase shift between oscillations of blood pressure (BP) and Doppler middle cerebral artery flow velocity (MCAFV) reflects continuous cerebral autoregulatory action. It is not known whether a similar phase shift exists for cortical hemodynamics (‘microvascular level’) assessed by near infrared spectroscopy (NIRS) and what the effects are of pathological conditions. This study investigates the phase relations between oscillations of BP, MCAFV and NIRS parameters in 38 healthy older adults and 28 patients with unilateral severe obstructive carotid disease. BP was recorded noninvasively by finger plethysmography. Stable 0.1 Hz oscillations of all hemodynamic parameters were induced by regular breathing at a rate of 6/min. Basic results were that: (1) BP-induced cortical microvascular oscillations (NIRS) follow those of macrovascular oscillations (MCAFV) with a phase of 80–90° (corresponding to 2–2.5 s at 0.1 Hz), most likely reflecting a transit time phenomenon; (2) oxy- and deoxyhemoglobin thereby oscillate in counterphase; (3) hemodynamic compromise in carotid obstruction leads to (a) delayed NIRS oscillations in comparison to BP which are highly correlated to a shorter phase lead of MCAFV against BP and (b) a decoupling of the oxy-/deoxyhemoglobin counterphase to 240°. Cortical hemodynamic responses to BP oscillations follow specific phase relationships due to cerebral autoregulatory action and circulatory transit times. With hemodynamic impairment, as in unilateral carotid obstruction, these phases are significantly changed reflecting disturbed autoregulation.     

Xenon-enhanced computed tomography cerebral blood flow measurements in acute cerebral ischemia: Review of 56 cases

Objective: Ischemic stroke must be diagnosed promptly if patients are to be treated with thrombolytic therapy. The diagnosis of acute cerebral ischemia, however, is usually based on clinical and computed tomography (CT) scan findings. CT scans are often normal in the first few hours after stroke. The purpose of this study was to determine whether Xenon-enhanced CT (XeCT) cerebral blood flow (CBF) studies could increase the sensitivity of stroke detection in the acute stage. Methods: CBF studies performed within 8 hours of symptom onset were evaluated in 56 patients who presented with hemispheric stroke symptoms. Mean CBF in the symptomatic vascular territory was calculated and compared with the corresponding contralateral area. CBF values below 18 mL/100g/min on 2 adjacent regions of interest were considered ischemic lesions. CT scans and angiograms were compared with the XeCt findings. Neurological condition on admission and discharge was evaluated by using National Institutes of Health Stroke Scale (NIHSS) scores. Results: The mean NIHSS score on admission was 12+/-5. Early CT scans were abnormal in 28 (50%) patients. There were 9 (16%) patients who had normal XeCT scans because of spontaneous reperfusion of the ischemic area. XeCT studies showed an ischemic lesion in 47 (84%) patients. In these patients, the mean CBF in the affected vascular territory was 16+/-8 mL/100g/min compared with 35+/-13 mL/100g/min in the contralateral specular territory (P<0.001). There were no false positive or negative XeCT studies, and the location of the perfusion defect corresponded with the CT and/or angiographic findings in all cases. Eight patients died (14%), and the 48 survivors (86%) had a mean NIHSS score of 9+/-6 on discharge. Conclusions: CBF measurements were correlated with the CT and angiographic results and greatly assisted in the diagnosis of acute ischemic stroke. XeCT studies used for estimating the location and extent of cerebral ischemia may be important in the triage of patients for acute stroke therapy.