Case Report: Arterial Spin Labeling Perfusion MRI Contribution for Clinical Implementation of Brain Disease

@#Currently, ASL is widely used as an additional breakthrough sequence in MRI due to acquiring reliable results. The case report aims to prove the efficacy and effectiveness of a quantitative method of ASL sequence through the calculation of the cerebral blood flow (CBF) on CBF maps in different cases. ASL sequence has been done on four patients with different cases. Then, the authors put 2 regions of interest (ROI) for measurement in normal and different regions on CBF maps and then calculated the average value result from CBF maps. ASL has been proven as a reliable and breakthrough sequence in MRI for detecting brain disease with a non-invasive method through the calculation of CBF value. ASL should be used as an additional protocol in brain examinations because it allows radiologists to assess the significance of CBF values using a quantitative method that is more reliable and non-invasiv

Functional Magnetic Resonance Imaging with Arterial Spin Labeling: Techniques and Potential Clinical and Research Applications

PURPOSE: To describe technical methods for functional magnetic resonance imaging (fMRI) study with arterial spin labeling (ASL) compared to blood oxygenation level-dependent (BOLD) technique and discuss the potential of ASL for research and clinical practice. MATERIALS AND METHODS: Task-based (n = 1) and resting-state fMRI (rs-fMRI) (n = 20) were performed using ASL and BOLD techniques. Results of both techniques were compared. RESULTS: For task-based fMRI with finger-tapping, the primary motor cortex of the contralateral frontal lobe and the ipsilateral cerebellum were activated by both BOLD and ASL fMRI. For rs-fMRI of sensorimotor network, functional connectivity showed similar results between BOLD and ASL. CONCLUSION: ASL technique has potential application in clinical and research fields because all brain perfusion imaging, CBF measurement, and rs-fMRI study can be performed in a single acquisition.

Functional Magnetic Resonance Imaging with Arterial Spin Labeling: Techniques and Potential Clinical and Research Applications

PURPOSE: To describe technical methods for functional magnetic resonance imaging (fMRI) study with arterial spin labeling (ASL) compared to blood oxygenation level-dependent (BOLD) technique and discuss the potential of ASL for research and clinical practice. MATERIALS AND METHODS: Task-based (n = 1) and resting-state fMRI (rs-fMRI) (n = 20) were performed using ASL and BOLD techniques. Results of both techniques were compared. RESULTS: For task-based fMRI with finger-tapping, the primary motor cortex of the contralateral frontal lobe and the ipsilateral cerebellum were activated by both BOLD and ASL fMRI. For rs-fMRI of sensorimotor network, functional connectivity showed similar results between BOLD and ASL. CONCLUSION: ASL technique has potential application in clinical and research fields because all brain perfusion imaging, CBF measurement, and rs-fMRI study can be performed in a single acquisition.

Comportamiento fractal espacial en la expansión de la distribución del flujo sanguíneo cerebral en Alzheimer / Spatial fractal behavior in the lengthening of cerebral bloodstream distribution in Alzheimer disease

El Alzheimer es una enfermedad neurodegenerativa que afecta a millones de personas alrededor del mundo. Las causas de esta aún son desconocidas. La geometría fractal es una teoría matemática que permite medir objetivamente la irregularidad de los objetos o procesos naturales; las estructuras y los comportamientos fisiológicos del cuerpo humano se pueden caracterizar matemáticamente a través de la dimensión fractal, la cual mide el grado de irregularidad o complejidad del fractal. La distribución del flujo sanguíneo cerebral en Alzheimer es notablemente irregular, por ello la dimensión fractal es una medida objetiva, la cual suponemos, cuantifica esta distribución. El coeficiente de expansión fractal se define para aquellos objetos dinámicos que poseen dimensión fractal y estima la expansión del fractal sobre su espacio circundante. Este coeficiente se asocia con el grado de conectividad que pueda poseer el fractal para expandirse. En el presente trabajo se determinaron los coeficientes de expansión fractal para la distribución del flujo sanguíneo cerebral en 21 pacientes con Alzheimer y en 11 sujetos normales en las zonas cerebrales posterior y anterior (tomados de la literatura). Los valores de los coeficientes resultaron ser mayores en Alzheimer respecto a los normales en las dos zonas, valores comparados respecto al espacio circundante en que sucede la expansión. Esto último sugiere el comportamiento de las conexiones neuronales en las zonas evaluadas.

Alzheimer disease is a neurodegenerative process affecting millions of persons at world scale. Even nowadays its causes are unknown. The fractal geometry is a mathematical theory allows to measure objectively the irregularity of objects or the natural processes; structures and physiologic behaviors of human body may be in a mathematical way be characterized through the fractal dimension, which to measure the irregularity or complexity degree of fractal. Distribution of cerebral blood flow in Alzheimer's disease is very irregular, thus the fractal dimension is an objective measure, which supposedly to quantify this distribution. The fractal expansion coefficient is defined for those dynamic objects having fractal dimension and estimates the fractal expansion on its surrounding space. This coefficient is associated with the connection that may to has the fractal for its expansion. The objective of present paperwas to determine the fractal expansion coefficients for the cerebral blood flow distribution in 21 patients presenting with Alzheimer's disease and in 11 normal subjects in the posterior and anterior cerebral zones, compared values regarding the surrounding space where expansion occur. This latter suggest the behavior of neuronal connections in assessed zones.

The variation of cerebral brain flow (CBF) and pathological characteristics in peripheral brain tissue of nidns after microsurgical resection of brain arterivanous malformations (BAVM) / 中华显微外科杂志

@#Objective To observe the variation of cerebral brain flow (CBF)and pathological characteristics in peripheral brain tissue of nidus after operation of brain arterivenous malformations (BAVM) and explore the mechanism and theaputic strategy of normal perfusion pressure breakdown (NPPB)after microsurgery. Methods 12 cases of BAVM that have received surgical resection were analyzed prospectively, and 8 cases of them were embolized with Onyx. The pathological characteristics of the nidus and peripheral brain tissue was observed with microscope and electron microscope. The variation of CBF in peripheral brain tissue of the nidus following microsurgical resection was observed by using Laser Doppuler Perfusion Imaging (LDPI) system. The monitering result of CBF in little meniugioma(n=6) during surgery was used as the control. Results There was small vessel expantion, neuron necrosis, gliocyte hyperplasia and blood brain barriar (BBB) destruction in peripheral brain tissue of BAVM nidus, the visibal brain tissue edema and inflammatory cell infiltration in peripheral brain tissue of the nidus and the revascularization in the emolized nidus vessels were observed after embolization with Onyx. There was significant change of CBF between pre-and post-operation (P<0.05),and after controlling depressurization during surgery was the increasing CBF step down (P<0.05). Conclusion The BBB breakdown and increasing CBF of peripheral brain tissue of the nidus may be the pathological foundation of brain hemorrhage and edema after BAVM microsurgical resection. So embolization before the operation, controlling depressuriation during and after surgery is the important methods for preventing and curing the NPPB of BAVM after microsurgery.

Usefulness of CT Perfusion in the Postoperative Evaluation of Ruptured Aneurysm / 대한뇌혈관외과학회지

OBJECTIVE: Our goal was to evaluate the usefulness of CT perfusion (CTP) in early detection of the post operative cerebral ischemia, alteration of treatment modality and patient prognosis in cerebral aneurysm patients. METHODS: 24 patients who underwent either surgical operation or endovascular coiling for ruptured aneurysms were selected. All patients undertook an angiogram, conventional CT, and CTP scan immediately following surgical operation or endovascular coiling. All patients performed a CT 2 weeks after treatment to evaluate possible development of a cerebral infarction. Postoperative CT results of patients with abnormal postoperative CTP scan findings were compared, and these results were compared with the CT results and clinical symptoms of patients who developed infarction or not. RESULTS: Of the 24 patients evaluated, 11 patients showed abnormal findings on CTP. 9 patients were diagnosed with cerebral infarction through a CT scan done 2 weeks after treatment; all exhibited abnormal CTP results immediately after treatment. Abnormal CTP findings were divided into two groups; patients with abnormal CBF and MTT maps, but with normal CBV maps, and patients with abnormal CBF, CBV and MTT maps. A correlation was seen between abnormality on CBV maps and cerebral infarction. Patients with abnormal CTP findings also exhibited poorer prognostic value. CONCLUSION: Postoperative CTP in ruptured aneurysm patients is a very useful and objective tool in evaluating abnormal cerebral hemodynamics. The CBV map of CTP is the most precisely predictable value of postoperative patient's status and alteration of treatement modality.

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.

Early Effect of Endotoxin on Cerebral Autoregulation / 대한마취과학회지

BACKGROUND: Under normal conditions, cerebral blood flow is regulated as cerebral perfusion pressure changes (autoregulation). Inflammatory conditions like bacterial meiningitis result in a loss of cerebral autoregulation several hours after exposure to bacterial endotoxin. Endotoxin appears to produce effects via the production of reactive oxygen species, such as the superoxide anion. METHODS: Cerebral blood flow (CBF) was measured by hydrogen clearance in anesthetized rats 30 minutes after intravenous endotoxin 5 mg/kg or normal saline (control). Mean arterial pressure was reduced from 100 mmHg to 80 mmHg and 60 mmHg by hemorragic hypotension, and cerebral blood flow was measured at each pressure. RESULTS: In the control group, CBF did not change when arterial pressure was reduced to 80 mmHg (113.9 ml vs 111.9 ml), but declined significantly at 60 mmHg (113.9 ml vs 88.4 ml). In the group treated with endotoxin, both a reduction of mean arterial pressure to 80 mmHg (129.8 ml vs 101.8 ml) and 60 mmHg (129.8 ml vs 78.4 ml) caused a significant reduction in CBF, indicating that autoregualtion had been abolished. CONCLUSIONS: The results of this study indicate that within minutes of endotoxin exposure, CBF markedly increased, and that the autoregualtion of CBF was inhibited.

Molecular mechanism of protective effects of estrogen on cerebral ischemia / 中国临床药理学与治疗学

Estrogen has the protective effect on cerebral ischemia in v ar ious ways. It not only can improve the regional cerebral blood flow during ische mia and rescue the remaining neurons alive, but also can reduce the injury of is chemia-reperfusion. In this article, we enumerate at the molecular level that e strogen has the properties of inhibiting the expression of VCAM and cytokines li ke TNF-? in the ischemia region, educing the overload of calcium and cytotoxic ity of EAA by modulating the calcium channels, and regulating related genes expr ession and anti-apoptosis. It is crucial for estrogen replacement therapy as a neutoprotectant clinically.